Performance Analysis of Telecommunication Systems

Publications

2013 - 2012 - 2011 - 2010 - 2009 - 2008 - 2007 - 2006 - 2005 - 2004 - 2003 - 2002 - 2001 - 2000 - 1999 - 1998 - 1997 - Theses

2013

• ARRL: A Criterion for Composable Safety and Systems Engineering
  Eric Verhulst, Jose Luis de la Vara, Bernhard H.C. Sputh & Vincenzo De Florio
  Proc. of the SAFECOMP 2013 Workshop on Generation of System Assurance Approaches for Safety-Critical Systems (SASSUR 2013), 2013.
  BibTeX
  
  Bibtex:
  @INPROCEEDINGS{VdlVSDF,
  author = {Eric Verhulst and Jose {Luis de la Vara} and
  Bernhard H.C. Sputh and Vincenzo {De Florio}},
  title = {{ARRL}: A Criterion for Composable Safety and Systems Engineering},
  booktitle = {Proc. of the SAFECOMP 2013 Workshop on
  Next Generation of System Assurance Approaches
  for Safety-Critical Systems (SASSUR 2013)},
  address = {Toulouse, France},
  tages = {},
  month = {September},
  day = {24--27},
  year = {2013},
  UURL = {http://www.pats.ua.ac.be/content/publications/2013/tobeadded},
  }
  
  Abstract:
  Not available

• The impact of dampening demand variability in a production/inventory system with multiple retailers
  B. Van Houdt & J.F. Perez
  Matrix-Analytic Methods in Stochastic Models, Springer Proceedings in Mathematics & Statistics, pp. 227-250, 2013.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{MAM7,
  author = {B. Van Houdt and J.F. Perez},
  title = {The impact of dampening demand variability in a production/inventory system with multiple retailers},
  booktitle = {Matrix-Analytic Methods in Stochastic Models, Springer Proceedings in Mathematics & Statistics},
  year = {2013},
  pages ={227-250},
  URL = {content/publications/2013/MAM7v2_Springer.pdf}
  }
  
  Abstract:
  Not available

• On the Constituent Attributes of Software and Organisational Resilience
  Vincenzo De Florio
  Interdisciplinary Science Reviews, Vol. 38, No. 2, Maney Publishing, 2013.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @ARTICLE{DF13a,
  author = {Vincenzo {De Florio}},
  title = {On the Constituent Attributes of Software and Organisational Resilience},
  journal = {Interdisciplinary Science Reviews},
  year = {2013},
  abstract = {Our societies are increasingly dependent on the services supplied by our computers and their software. Forthcoming new technology is only exacerbating this dependence by increasing the number, the performance, and the degree of autonomy and inter-connectivity of software-empowered computers and cyber-physical “things”, which translates into unprecedented scenarios of interdependence. As a consequence, guaranteeing the persistence-of-identity of individual and collective software systems and software-backed organisations becomes an increasingly important prerequisite towards sustaining the safety, security, and quality of the computer services supporting human societies. Resilience is the term used to refer to the ability of a system to retain its functional and non-functional identity. In the present article we conjecture that a better understanding of resilience may be reached by decomposing it into a number of ancillary constituent properties, the same way as a better insight in system dependability was obtained by breaking it down into safety, availability, reliability, and other sub-properties. Three of the main sub-properties of resilience proposed here refer respectively to the ability to perceive environmental changes; to understand the implications introduced by those changes; and to plan and enact adjustments intended to improve the system-environment fit. A fourth property characterises the way the above abilities manifest themselves in computer systems. The four properties are then analyzed in three families of case studies, each consisting of three software systems that embed different resilience methods. Our major conclusion is that reasoning in terms of our resilience sub-properties may help revealing the characteristics—and in particular the limitations—of classic methods and tools meant to achieve system and organisational resilience. We conclude by suggesting that our method may prelude to meta-resilient systems—systems, that is, able to adjust optimally their own resilience with respect to changing environmental conditions.},
  volume = {38},
  number = {2},
  month = {June},
  year = {2013},
  nopagesyet = {185--197},
  publisher = {Maney Publishing},
  URL = {content/publications/2013/otcaosr-v2.4.pdf}
  }
  
  Abstract:
  Our societies are increasingly dependent on the services supplied by our computers and their software. Forthcoming new technology is only exacerbating this dependence by increasing the number, the performance, and the degree of autonomy and inter-connectivity of software-empowered computers and cyber-physical “things”, which translates into unprecedented scenarios of interdependence. As a consequence, guaranteeing the persistence-of-identity of individual and collective software systems and software-backed organisations becomes an increasingly important prerequisite towards sustaining the safety, security, and quality of the computer services supporting human societies. Resilience is the term used to refer to the ability of a system to retain its functional and non-functional identity. In the present article we conjecture that a better understanding of resilience may be reached by decomposing it into a number of ancillary constituent properties, the same way as a better insight in system dependability was obtained by breaking it down into safety, availability, reliability, and other sub-properties. Three of the main sub-properties of resilience proposed here refer respectively to the ability to perceive environmental changes; to understand the implications introduced by those changes; and to plan and enact adjustments intended to improve the system-environment fit. A fourth property characterises the way the above abilities manifest themselves in computer systems. The four properties are then analyzed in three families of case studies, each consisting of three software systems that embed different resilience methods. Our major conclusion is that reasoning in terms of our resilience sub-properties may help revealing the characteristics—and in particular the limitations—of classic methods and tools meant to achieve system and organisational resilience. We conclude by suggesting that our method may prelude to meta-resilient systems—systems, that is, able to adjust optimally their own resilience with respect to changing environmental conditions.

2012

• Vehicular ad hoc networking based on the incorporation of geographical information in the IPv6 header
  Wim Vandenberghe, Erwin Van de Velde, Chris Blondia, Ingrid Moerman & Piet Demeester
  EURASIP Journal on Wireless Communications and Networking, 2012.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @Article{,
  author = {Wim Vandenberghe, Erwin Van de Velde, Chris Blondia, Ingrid Moerman, Piet Demeester},
  title = {Vehicular ad hoc networking based on the incorporation of geographical information in the IPv6 header},
  journal = {EURASIP Journal on Wireless Communications and Networking},
  year = {2012},
  month = {October},
  issn = {1687-1499},
  abstract = {Abstract
  Several approaches can be identified in the domain of vehicular ad hoc networks (VANET).
  Internet Protocol version 6 (IPv6) networking and non-IP geographical networking can each
  fulfill a subset of the application requirements. In general, a combination of both techniques
  is proposed to meet all of the application requirements. In this case, packets of one VANET
  routing protocol are encapsulated inside packets of another. This tunneling, together with
  the position service required for non-IP geographical unicasting, makes such a combined
  solution rather complex, and hence more challenging to implement, debug, and maintain. In
  this article, a new VANET approach is presented that relies on the key assumptions that
  geo-anycast functionality is not required by the applications, and that geographic unicasting
  is not needed when IP-based unicasting is provided. This enables the adoption of an
  IPv6-only VANET solution, removing the need for tunneling and position services. New
  techniques are required to support IPv6-based geo-broadcasting. In this article, it is
  described how addresses should be assigned, how geographical data can be incorporated in
  the IPv6 address, how the other IPv6 header fields can be used to contain additional VANET
  information, and how routing should be handled to guarantee that no modifications are
  required to the application units. The implementation of the proposed techniques is
  described, and the correct functionality of the solutions is experimentally demonstrated.
  },
  keywords = {Vehicular ad hoc networks, VANET, IPv6, Geographical networking}
  url = {URL = {content/publications/2012/IPv6Addressing.pdf}
  }
  
  Abstract:
  Abstract approaches can be identified in the domain of vehicular ad hoc networks (VANET). Protocol version 6 (IPv6) networking and non-IP geographical networking can each a subset of the application requirements. In general, a combination of both techniques proposed to meet all of the application requirements. In this case, packets of one VANET protocol are encapsulated inside packets of another. This tunneling, together with position service required for non-IP geographical unicasting, makes such a combined rather complex, and hence more challenging to implement, debug, and maintain. In article, a new VANET approach is presented that relies on the key assumptions that functionality is not required by the applications, and that geographic unicasting not needed when IP-based unicasting is provided. This enables the adoption of an VANET solution, removing the need for tunneling and position services. New are required to support IPv6-based geo-broadcasting. In this article, it is how addresses should be assigned, how geographical data can be incorporated in IPv6 address, how the other IPv6 header fields can be used to contain additional VANET and how routing should be handled to guarantee that no modifications are to the application units. The implementation of the proposed techniques is and the correct functionality of the solutions is experimentally demonstrated.

• A fast Newton s iteration for M/G/1-type and GI/M/1-type Markov chains
  J.F. Perez, M. Telek & B. Van Houdt
  Stochastic Models, Vol. 28, No. 4, pp. 557-583, 2012.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{sm2012,
  author = {J.F. Perez, M. Telek and B. Van Houdt},
  title = {A fast Newton's iteration for M/G/1-type and GI/M/1-type Markov chains},
  journal= {Stochastic Models},
  volume = {28},
  number = {4},
  pages = {557-583},
  year = {2012},
  URL = {content/publications/2012/PerezTelekVanHoudt_NewtonMG1.pdf}
  }
  
  Abstract:
  Not available

• Pull versus Push Mechanism in Large Distributed Networks: Closed Form Results
  W. Minnebo & B. Van Houdt
  Proceedings of ITC 2012 (Best Paper Award), Krakau, Poland, 2012.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{qest2012,
  author = {W. Minnebo and B. Van Houdt},
  title = {Pull versus Push Mechanism in Large Distributed Networks: Closed Form Results },
  booktitle = {Proceedings of ITC 2012 (Best Paper Award)},
  year = {2012},
  location = {Krakau, Poland},
  URL = {content/publications/2012/ITC2012.pdf}
  }
  
  Abstract:
  Not available

• A multi-layer fluid queue with boundary phase transitions and its application to the analysis of multi-type queues with general customer impatience
  G. Horvath & B. Van Houdt
  Proceedings of QEST 2012, London, UK, 2012.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{qest2012,
  author = {G. Horvath and B. Van Houdt},
  title = {A multi-layer fluid queue with boundary phase transitions and its application to the analysis of multi-type queues with general customer impatience },
  booktitle = {Proceedings of QEST 2012},
  year = {2012},
  location = {London, UK},
  URL = {content/publications/2012/QEST2012.pdf}
  }
  
  Abstract:
  Not available

• Multimedia multicast performance analysis for 802.11n network cards
  N. Letor, W. Torfs & C. Blondia
  Proc. of Wireless Days 2012 (WD 12), 2012.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @ARTICLE{nletor12a,
  author = {N. Letor, W. Torfs, C. Blondia},
  title = {Multimedia multicast performance analysis for 802.11n network cards},
  abstract = {The technical evolution of Wi-Fi networks has made it possible to attain very high speeds for delivering content to users. However multicast transmissions never received the same level of attention as unicast transmissions in the IEEE802.11n standard. In this paper, we experimentally assess the viability of employing commercially available IEEE802.11n hardware to multicast multimedia content, which requires high bandwidth and low delay. Since the leader based multicast scheme is an improvement to the standard multicast scheme and can be implemented with commercially available hardware, this method and a variation thereof are compared to the standard multicast method.},
  booktitle = {Proc. of Wireless Days 2012 (WD'12)},
  year = {2012},
  month = {November}
  URL = {content/publications/2012/PID2561205.pdf}
  }
  
  Abstract:
  The technical evolution of Wi-Fi networks has made it possible to attain very high speeds for delivering content to users. However multicast transmissions never received the same level of attention as unicast transmissions in the IEEE802.11n standard. In this paper, we experimentally assess the viability of employing commercially available IEEE802.11n hardware to multicast multimedia content, which requires high bandwidth and low delay. Since the leader based multicast scheme is an improvement to the standard multicast scheme and can be implemented with commercially available hardware, this method and a variation thereof are compared to the standard multicast method.

• An Eco-Friendly Hybrid Urban Computing Network Encompassing Community-Based Wireless LAN Access and Wireless Sensor Networking
  Maarten Wijnants, Wim Lamotte, Nicolas Letor, Chris Blondia, Eli De Poorter, Dries Naudts, Stijn Verstichel, Nelson Matthys & Christophe Huygens
  Proc. of The IEEE International Conference on Cyber, Physical and Social Computing (CPSCOM 2012), 2012.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @ARTICLE{greenwecan12a,
  author = {Maarten Wijnants, Wim Lamotte, Nicolas Letor, Chris Blondia, Eli De Poorter, Dries Naudts, Stijn Verstichel, Nelson Matthys, Christophe Huygens},
  title = {An Eco-Friendly Hybrid Urban Computing Network Encompassing Community-Based Wireless LAN Access and Wireless Sensor Networking},
  abstract = {Computer-enhanced smart environments, dis- tributed environmental monitoring, wireless communication, energy conservation and sustainable technologies, user mobil- ity, ubiquitous access to Internet-located data and services, and innovation as a tool for service differentiation are all significant contemporary research subjects and societal developments. This position paper presents the design of a hybrid municipal network infrastructure that, to a lesser or greater degree, incorporates aspects from each of these topics by integrat- ing a community-based Wi-Fi access network with Wireless Sensor Network (WSN) functionality. The former component provides free wireless Internet connectivity by harvesting the Internet subscriptions of city inhabitants. To minimize session interruptions for mobile clients, this subsystem incorporates technology that achieves (near-)seamless handover between Wi- Fi access points. The WSN component on the other hand renders it feasible to sense physical properties and to realize the Internet of Things (IoT) paradigm. This in turn scaffolds the development of value-added end-user applications that are consumable through the community-based access network. The WSN subsystem invests substantially in ecological considera- tions by means of a green sensor middleware and a distributed reasoning framework that collaboratively aim to minimize the network’s global energy consumption. Via the discussion of two illustrative applications that are currently being developed as part of a concrete smart city deployment, we offer a taste of the myriad of innovative digital services in an extensive spectrum of application domains that is unlocked by the proposed platform.},
  booktitle = {Proc. of The IEEE International Conference on Cyber, Physical and Social Computing (CPSCOM 2012) },
  year = {2012},
  month = {November}
  URL = {content/publications/2012/gwc2012.pdf}
  }
  
  Abstract:
  Computer-enhanced smart environments, dis- tributed environmental monitoring, wireless communication, energy conservation and sustainable technologies, user mobil- ity, ubiquitous access to Internet-located data and services, and innovation as a tool for service differentiation are all significant contemporary research subjects and societal developments. This position paper presents the design of a hybrid municipal network infrastructure that, to a lesser or greater degree, incorporates aspects from each of these topics by integrat- ing a community-based Wi-Fi access network with Wireless Sensor Network (WSN) functionality. The former component provides free wireless Internet connectivity by harvesting the Internet subscriptions of city inhabitants. To minimize session interruptions for mobile clients, this subsystem incorporates technology that achieves (near-)seamless handover between Wi- Fi access points. The WSN component on the other hand renders it feasible to sense physical properties and to realize the Internet of Things (IoT) paradigm. This in turn scaffolds the development of value-added end-user applications that are consumable through the community-based access network. The WSN subsystem invests substantially in ecological considera- tions by means of a green sensor middleware and a distributed reasoning framework that collaboratively aim to minimize the network’s global energy consumption. Via the discussion of two illustrative applications that are currently being developed as part of a concrete smart city deployment, we offer a taste of the myriad of innovative digital services in an extensive spectrum of application domains that is unlocked by the proposed platform.

• Service-oriented Communities: Models and Concepts towards Fractal Social Organizations
  Vincenzo De Florio, Antonio Coronato, Mohamed Bakhouya & Giovanna Di Marzo Serugendo
  Proceedings of the 8th International Conference on signal, image technology and internet based systems (SITIS 2012), Sorrento, Italy, IEEE, 2012.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{DFCBD12,
  author = {Vincenzo {De Florio} and Antonio Coronato and Mohamed Bakhouya and Giovanna {Di Marzo Serugendo}},
  title = {Service-oriented Communities: Models and
  Concepts towards Fractal Social Organizations},
  booktitle = {Proceedings of the 8th International Conference on signal, image technology and internet based systems (SITIS 2012)},
  year = {2012},
  publisher = {IEEE},
  location = {Sorrento, Italy},
  abstract={It is described an abstract model for the defini-
  tion and the dynamic evolution of “communities of actants”
  originating from a given reference society of roles. Multiple
  representations are provided, showing how communities evolve
  with respect to their reference societies. In particular we show
  how such representations are self-similar and factorisable into
  “prime” constituents. An operating model is then introduced
  that describes the life-cycle of the communities of actants. After
  this a software component is presented—the service-oriented
  community—and its features are described in terms of the above
  mentioned models. Finally it is shown how such component can
  constitute the building block of a novel architecture for the design
  of fractal social organizations.},
  date = {25--29 November, 2012},
  url = {content/publications/2012/SoC12b.pdf}
  }
  
  Abstract:
  It is described an abstract model for the defini- and the dynamic evolution of “communities of actants” from a given reference society of roles. Multiple are provided, showing how communities evolve respect to their reference societies. In particular we show such representations are self-similar and factorisable into constituents. An operating model is then introduced describes the life-cycle of the communities of actants. After a software component is presented—the service-oriented its features are described in terms of the above models. Finally it is shown how such component can the building block of a novel architecture for the design of fractal social organizations.

• Existing challenges and new opportunities in context-aware systems
  Waltenegus Dargie, Juha Plosila & Vincenzo De Florio
  Proceedings of the 2012 ACM Conference on Ubiquitous Computing, Pittsburgh, Pennsylvania, ACM, 2012.
  BibTeX
  
  Bibtex:
  @INPROCEEDINGS{DPDF12,
  author = {Waltenegus Dargie and Juha Plosila and Vincenzo {De Florio}},
  title = {Existing challenges and new opportunities in context-aware systems},
  booktitle = {Proceedings of the 2012 ACM Conference on Ubiquitous Computing},
  year = {2012},
  publisher = {ACM},
  location = {Pittsburgh, Pennsylvania},
  date = {5--8 September, 2012},
  }
  
  Abstract:
  Not available

• MultiMAC: A Multiple MAC Network Stack Architecture for TinyOS
  Daniel van den Akker & Chris Blondia
  Computer Communications and Networks (ICCCN), 2012 21st International Conference on, pp. 1 -5, 2012.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{dvdakker_ICCCN12,
  author={Daniel van den Akker and Chris Blondia},
  title={MultiMAC: A Multiple MAC Network Stack Architecture for TinyOS},
  booktitle={Computer Communications and Networks (ICCCN), 2012 21st International Conference on},
  year={2012},
  month={30 2012-aug. 2},
  pages={1 -5},
  keywords={},
  doi={10.1109/ICCCN.2012.6289210},
  abstract={Due to the extreme energy requirements often found in sensor networks and the fact that these sensor networks are being used for an increasingly wide variety of applications, there currently exist many different sensor network MAC protocols each optimised for a different set of application requirements. Since these MAC protocols are not compatible with each other, there is generally no interoperability between sensor networks. This lack of interoperability becomes a severe problem when connectivity between sensor networks is required. In this paper, we demonstrate the feasibility of using Virtual Gateways, sensor nodes running multiple MAC protocols simultaneously on top of a single radio interface, to enable connectivity between sensor networks. To this end we have developed MultiMAC, a network stack for TinyOS capable of running multiple MAC protocols at the same time. We show that the architecture of the MultiMAC stack is flexible and extensible enough to support a wide variety of MAC protocols and that the overhead of this network stack is minimal.},
  URL = {content/publications/2012/dvdakker2012ICCCN.pdf}
  }
  
  Abstract:
  Due to the extreme energy requirements often found in sensor networks and the fact that these sensor networks are being used for an increasingly wide variety of applications, there currently exist many different sensor network MAC protocols each optimised for a different set of application requirements. Since these MAC protocols are not compatible with each other, there is generally no interoperability between sensor networks. This lack of interoperability becomes a severe problem when connectivity between sensor networks is required. In this paper, we demonstrate the feasibility of using Virtual Gateways, sensor nodes running multiple MAC protocols simultaneously on top of a single radio interface, to enable connectivity between sensor networks. To this end we have developed MultiMAC, a network stack for TinyOS capable of running multiple MAC protocols at the same time. We show that the architecture of the MultiMAC stack is flexible and extensible enough to support a wide variety of MAC protocols and that the overhead of this network stack is minimal.

• A matrix geometric representation for the queue length distribution of multitype semi-Markovian queues
  B. Van Houdt
  Performance Evaluation, Vol. 69, No. 7-8, pp. 299-314, 2012.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{perf2012,
  author = {B. Van Houdt},
  title = {A matrix geometric representation for the queue length distribution of multitype semi-Markovian queues },
  booktitle = {Performance Evaluation},
  volume = {69},
  number = {7-8},
  pages = {299-314},
  year = {2012},
  URL = {content/publications/2012/Perf2012_multitype.pdf}
  }
  
  Abstract:
  Not available

• Fluid limit of an asynchronous optical packet switch with shared per link full range wavelength conversion
  B. Van Houdt & L. Bortolussi
  Performance Evaluation Review (Sigmetrics 2012), Vol. 40, No. , pp. 113-124, 2012.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{sigmetrics2012,
  author = {B. Van Houdt and L. Bortolussi},
  title = {Fluid limit of an asynchronous optical packet switch with shared per link full range wavelength conversion},
  booktitle = {Performance Evaluation Review (Sigmetrics 2012)},
  volume = {40},
  number = {},
  pages = {113-124},
  year = {2012},
  URL = {content/publications/2012/Sigmetrics12.pdf}
  }
  
  Abstract:
  Not available

• Analysis of the adaptive MMAP[K]/PH[K]/1 queue: a multi-type queue with adaptive arrivals and general impatience
  B. Van Houdt
  European Journal of Operational Research (EJOR), Vol. 220, No. 3, pp. 695-704, 2012.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{ejor2012,
  author = {B. Van Houdt},
  title = {Analysis of the adaptive MMAP[K]/PH[K]/1 queue: a multi-type queue with adaptive arrivals and general impatience},
  booktitle = {European Journal of Operational Research (EJOR)},
  volume = {220},
  number = {3},
  pages = {695-704},
  year = {2012},
  URL = {content/publications/2012/EJOR2012.pdf}
  }
  
  Abstract:
  Not available

• Towards Parsimonious Resource Allocation in Context-Aware n-Version Programming
  Jonas Buys, Vincenzo De Florio & Chris Blondia
  Proceedings of the 7th IET System Safety Conference, The Institute of Engineering and Technology, 2012.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{Buys2012c,
  author = {Jonas Buys, Vincenzo {De Florio} and Chris Blondia},
  title = {Towards Parsimonious Resource Allocation in Context-Aware n-Version
  Programming},
  booktitle = {Proceedings of the 7th IET System Safety Conference},
  year = {2012},
  publisher = {The Institute of Engineering and Technology},
  url = {http://euterpe.cmi.ua.ac.be/~jbuys/papers/ietss2012.pdf}}
  }
  
  Abstract:
  Not available

• Safety Enhancement Through Situation-aware User Interfaces
  Vincenzo De Florio & Chris Blondia
  Proceedings of the 7th International IET System Safety Conference, Edinburgh, UK, IET, 2012.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{DFB12,
  author = {Vincenzo {De Florio} and Chris Blondia},
  title = {Safety Enhancement Through
  Situation-aware User Interfaces},
  booktitle = {Proceedings of the 7th International IET System Safety Conference},
  year = {2012},
  publisher = {IET},
  location = {Edinburgh, UK},
  date = {15--18 October, 2012},
  abstract={Due to their privileged position halfway between the physical and the
  cyber universe, user interfaces may play an important role in
  learning, preventing, and tolerating scenarios affecting the
  safety of the mission and the user's quality of experience. This
  vision is embodied here in the main ideas and a proof-of-
  concepts
  implementation of user interfaces combining
  dynamic profiling with context- and situation-awareness and
  autonomic software adaptation.},
  url = {content/publications/2012/ss12.pdf}
  }
  
  Abstract:
  Due to their privileged position halfway between the physical and the universe, user interfaces may play an important role in preventing, and tolerating scenarios affecting the of the mission and the user s quality of experience. This is embodied here in the main ideas and a proof-of- of user interfaces combining profiling with context- and situation-awareness and autonomic software adaptation.

• Formal Modeling of Socio-technical Collective Adaptive Systems
  Antonio Coronato, Vincenzo De Florio, Mohamed Bakhouya & Giovanna Di Marzo Serugendo
  Proceedings of the first International Workshop on Adaptive Service Ecosystems: Nature and Socially Inspired Solutions (ASENSIS 2012), Lyon, France, IEEE, 2012.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{CDFBD12,
  author = {Antonio Coronato and Vincenzo {De Florio} and Mohamed Bakhouya and Giovanna {Di Marzo Serugendo}},
  title = {Formal Modeling of Socio-technical Collective Adaptive Systems},
  booktitle = {Proceedings of the first International Workshop on Adaptive Service Ecosystems: Nature and Socially Inspired Solutions (ASENSIS 2012)},
  year = {2012},
  publisher = {IEEE},
  location = {Lyon, France},
  abstract={Socio-technical collective adaptive systems (CAS)
  are composed of different heterogeneous parts or entities
  (e.g., individuals, groups, computers, robots, agents, devices,
  software, services, sensors) that interact collectively in a complex
  and largely unpredictable manner. Their ability to be
  adaptive requires incorporating mechanisms that allow entities
  to interact and perform actions favoring the emergence of
  a global desired behavior or service. Therefore, analyzing
  and discovering new emerging behaviors and/or unexpected
  abnormal behaviors, as well as new opportunities of services
  emergence, require methods and tools for formally specifying,
  verifying, and validating foundational properties at design
  time and while running (runtime verification). In this paper,
  three emerging formal methods—situation calculus, ambient
  calculus, and bigraphical reactive systems—are first studied
  to shed more light on their appropriateness for specifying
  and verifying socio-technical CAS. A case study is used and
  its formal model using these methods is presented to show
  their fundamental features and limitations for modeling these
  systems.
  },
  date = {10 September, 2012},
  url = {content/publications/2012/fmoscas12.pdf}
  }
  
  Abstract:
  Socio-technical collective adaptive systems (CAS) composed of different heterogeneous parts or entities individuals, groups, computers, robots, agents, devices, services, sensors) that interact collectively in a complex largely unpredictable manner. Their ability to be requires incorporating mechanisms that allow entities interact and perform actions favoring the emergence of global desired behavior or service. Therefore, analyzing discovering new emerging behaviors and/or unexpected behaviors, as well as new opportunities of services require methods and tools for formally specifying, and validating foundational properties at design and while running (runtime verification). In this paper, emerging formal methods—situation calculus, ambient and bigraphical reactive systems—are first studied shed more light on their appropriateness for specifying verifying socio-technical CAS. A case study is used and formal model using these methods is presented to show fundamental features and limitations for modeling these

• Towards Meta-Adaptation support with Reusable and Composable Adaptation Components
  Ning Gui & Vincenzo De Florio
  Proceedings of the sixth IEEE International Conference on Self-Adaptive and Self-Organizing Systems (SASO 2012), Lyon, France, IEEE, 2012.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{GDF12,
  author = {Ning Gui and Vincenzo {De Florio}},
  title = {Towards Meta-Adaptation support with Reusable and Composable Adaptation Components},
  booktitle = {Proceedings of the sixth IEEE International Conference on Self-Adaptive and Self-Organizing Systems (SASO 2012)},
  year = {2012},
  publisher = {IEEE},
  abstract = {Software systems today are increasingly used in
  changing environments and expected to adapt with variable
  adaptation concerns. This requirement demands a systematic
  approach to efficiently construct system global adaptation
  behaviour according to the dynamic adaptation requirements.
  This paper presents Transformer---a framework for
  adaptation behaviour composition support based on reusable
  and composable adaptation components. Rather than using
  one adaptation module for all possible contexts, Transformer
  constructs system global adaptation behaviour by contextually
  fusing adaptation plans from multiple adaptation components.
  Explicit conflict resolution is provided to handle possible
  conflicts raised in the fusion process. In addition to the
  description of the Transformer framework, this paper also
  presents its implementation and its application to a video
  conferencing system. Qualitative analysis and simulation
  results show that our framework exhibits significant advantage
  over traditional approaches in light of flexibility and
  reusability of the adaptation components with little
  performance overhead.},
  location = {Lyon, France},
  url = {content/publications/2012/saso2012.pdf},
  date = {10--14 September, 2012},
  }
  
  Abstract:
  Software systems today are increasingly used in environments and expected to adapt with variable concerns. This requirement demands a systematic to efficiently construct system global adaptation according to the dynamic adaptation requirements. paper presents Transformer---a framework for behaviour composition support based on reusable composable adaptation components. Rather than using adaptation module for all possible contexts, Transformer system global adaptation behaviour by contextually adaptation plans from multiple adaptation components. conflict resolution is provided to handle possible raised in the fusion process. In addition to the of the Transformer framework, this paper also its implementation and its application to a video system. Qualitative analysis and simulation show that our framework exhibits significant advantage traditional approaches in light of flexibility and of the adaptation components with little performance overhead.

• WSDM-enabled Autonomic Augmentation of Classical Multi-Version Software Fault-Tolerance Mechanisms
  Roeland Dillen, Jonas Buys, Vincenzo De Florio & Chris Blondia
  Proceedings of the SAFECOMP 2012 Workshops, Lecture Notes in Computer Science, Magdeburg, Germany, Lecture Notes in Computer Science (LNCS), Vol. 7613, pp. 294-306, Springer, F. Ortmeier and P. Daniel, 2012.
  Presented at the 1st Workshop on DEpendable and SEcure Computing for Large-scale Complex Critical Infrastructures (DESEC4LCCI2012)
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{Buys2012b,
  author = {Roeland Dillen and Jonas Buys and Vincenzo {De Florio} and Chris Blondia},
  title = {WSDM-enabled Autonomic Augmentation of Classical Multi-Version Software Fault-Tolerance Mechanisms},
  booktitle = {Proceedings of the SAFECOMP 2012 Workshops, Lecture Notes in Computer Science},
  year = {2012},
  editor = {F. Ortmeier and P. Daniel},
  volume = {7613},
  series = {Lecture Notes in Computer Science (LNCS)},
  pages = {294--306},
  publisher = {Springer},
  note = {Presented at the 1st Workshop on DEpendable and SEcure Computing for Large-scale Complex Critical Infrastructures (DESEC4LCCI2012)},
  location = {Magdeburg, Germany},
  abstract = {Web services are increasingly deployed in many enterprise
  applications. For this type of applications, dependability issues are usually resolved by introducing some form of redundancy in the system.
  Whereas hardware redundancy schemes have traditionally been defined
  through static congurations based on worst-case analysis, the enhanced
  flexibility and interoperability of web services allows for dynamic (self-)
  management of redundancy at the application layer. Combining this advantage with service-oriented platforms such as OSGi facilitates the replication of software components and their integration within redundancy
  schemes. The application of such redundancy schemes inevitably comes
  at a price though---primarily due to the allocation of additional system resources. It is often unknown to the service provider how much
  redundancy and management complexity is required. Furthermore, the
  degree of redundancy and the dependability strategy to be employed
  may be restricted by the budget and requirements of the client, both
  of which may vary. In this paper, we propose a solution to allow the
  client to express a trade-off between its dependability requirements and
  its available budget at request level. A dedicated service provider will
  then attempt to honour these objectives---failing to do so would obviously result in failure from the client point of view. Furthermore, we
  show how classical multi-version software fault-tolerance techniques can
  be augmented with advanced redundancy management leveraging the
  Web Services Distributed Management standard.},
  url = {http://euterpe.cmi.ua.ac.be/~jbuys/papers/desec4lcci2012.pdf}}
  
  Abstract:
  Web services are increasingly deployed in many enterprise For this type of applications, dependability issues are usually resolved by introducing some form of redundancy in the system. hardware redundancy schemes have traditionally been defined static congurations based on worst-case analysis, the enhanced and interoperability of web services allows for dynamic (self-) of redundancy at the application layer. Combining this advantage with service-oriented platforms such as OSGi facilitates the replication of software components and their integration within redundancy The application of such redundancy schemes inevitably comes a price though---primarily due to the allocation of additional system resources. It is often unknown to the service provider how much and management complexity is required. Furthermore, the of redundancy and the dependability strategy to be employed be restricted by the budget and requirements of the client, both which may vary. In this paper, we propose a solution to allow the to express a trade-off between its dependability requirements and available budget at request level. A dedicated service provider will attempt to honour these objectives---failing to do so would obviously result in failure from the client point of view. Furthermore, we how classical multi-version software fault-tolerance techniques can augmented with advanced redundancy management leveraging the Web Services Distributed Management standard.

• Overhead Analysis of Embedded Wireless Testbeds
  Nathan Samson, Glenn Daneels, Bart Braem & Chris Blondia
  The 1st International Workshop on Community Networks and Bottom-up-Broadband (CNBuB 2012), Barcelona, Spain, pp. 651-658, IEEE Computer Society, 2012.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{bbraem2012CNBuB,
  author = {Nathan Samson and Glenn Daneels and Bart Braem and Chris Blondia},
  title = {Overhead Analysis of Embedded Wireless Testbeds},
  booktitle = {The 1st International Workshop on Community Networks
  and Bottom-up-Broadband (CNBuB 2012)},
  publisher = {IEEE Computer Society},
  year = {2012},
  month = {October},
  location = {Barcelona, Spain},
  pages = {651-658},
  URL = {content/publications/2012/bbraem2012cnbub.pdf},
  abstract = {As community networks are being deployed more often, interest in using them as testbeds is growing too. Frame- works like the cOntrol and Management Framework (OMF) are helpful software tools to organize, control and instrument the testbeds deployed on those networks. However, community networks have a very heterogeneous infrastructure in which less powerful, embedded devices will play an important role due to their low cost. This work will analyze the overhead generated by the OMF framework when deployed on embedded devices. Possible performance hits introduced by the overhead on both desktop and embedded systems will be pre- sented and compared.}
  
  Abstract:
  As community networks are being deployed more often, interest in using them as testbeds is growing too. Frame- works like the cOntrol and Management Framework (OMF) are helpful software tools to organize, control and instrument the testbeds deployed on those networks. However, community networks have a very heterogeneous infrastructure in which less powerful, embedded devices will play an important role due to their low cost. This work will analyze the overhead generated by the OMF framework when deployed on embedded devices. Possible performance hits introduced by the overhead on both desktop and embedded systems will be pre- sented and compared.

• Transformer: an adaptation framework with contextual adaptation behavior composition support
  Ning Gui , Vincenzo De Florio & Tom Holvoet
  Software: Practice & Experience, Vol. 46, No. 8, Wiley, 2012.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{GDFB12a,
  author = {Ning Gui and Vincenzo {De Florio} and Tom Holvoet},
  title = {Transformer: an adaptation framework with contextual adaptation behavior composition support},
  journal = {Software: Practice & Experience},
  year = {2012},
  volume = {46},
  number = {8},
  nopagesyet = {185--197},
  publisher = {Wiley},
  URL = {content/publications/2012/spe12.pdf}
  }
  
  Abstract:
  Not available

• Innovations and Approaches for Resilient and Adaptive Systems
  Vincenzo De Florio (editor)
  pp. 343, IGI Global, Vincenzo De Florio, 2012.
  Available at http://www.igi-global.com/book/innovations-approaches-resilient-adaptive-systems/66376,
  BibTeX | PDF Available
  
  Bibtex:
  @Book{D12b,
  editor = {Vincenzo De Florio},
  author = {Vincenzo De Florio (editor)},
  title = {Innovations and Approaches for Resilient and Adaptive Systems},
  publisher = {IGI Global},
  address = {Hershey, PA 17033, USA},
  year = {2012},
  pages = {343},
  url = {content/publications/2012/InnovationsAndApproachesForResilientAndAdaptiveSystems.pdf},
  note = {Available at http://www.igi-global.com/book/innovations-approaches-resilient-adaptive-systems/66376},
  }
  
  Abstract:
  Not available

• On the Role of Perception and Apperception in Ubiquitous and Pervasive Environments
  Vincenzo De Florio
  Proceedings of the 3rd Workshop on Service Discovery and Composition in Ubiquitous and Pervasive Environments (SUPE 2012), Niagara Falls, Ontario, Canada, Elsevier, 2012.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{DF12b,
  author = {Vincenzo De Florio},
  title = {On the Role of Perception and Apperception in Ubiquitous and Pervasive Environments},
  booktitle = {Proceedings of the 3rd Workshop on Service Discovery and Composition in Ubiquitous and Pervasive Environments (SUPE'2012)},
  address = {Niagara Falls, Ontario, Canada},
  location = {Niagara Falls, Ontario, Canada},
  tages = {unknown},
  month = {August},
  day = {27--29},
  year = {2012},
  publisher = {Elsevier},
  abstract = {Building on top of classic work on the perception of natural systems this paper addresses the role played by such quality
  in environments where change is the rule rather than the exception. As in natural systems, perception in software systems
  takes two major forms: sensory perception and awareness (also known as apperception). For each of these forms we
  introduce semi-formal models that allow us to discuss and characterize perception and apperception failures in software
  systems evolving in environments subjected to rapid and sudden changes—such as those typical of ubiquitous and
  pervasive computing. Our models also provide us with two partial orders to compare such software systems with one
  another as well as with reference environments. When those environments evolve or change, or when the software
  themselves evolve after their environments, the above partial orders may be used to compute new environmental fits and
  different strategic fits and gain insight on the degree of resilience achieved through the current adaptation steps.},
  URL = {content/publications/2012/SUPE_99_DeFlorio.pdf}
  }
  
  Abstract:
  Building on top of classic work on the perception of natural systems this paper addresses the role played by such quality environments where change is the rule rather than the exception. As in natural systems, perception in software systems two major forms: sensory perception and awareness (also known as apperception). For each of these forms we semi-formal models that allow us to discuss and characterize perception and apperception failures in software evolving in environments subjected to rapid and sudden changes—such as those typical of ubiquitous and computing. Our models also provide us with two partial orders to compare such software systems with one as well as with reference environments. When those environments evolve or change, or when the software evolve after their environments, the above partial orders may be used to compute new environmental fits and different strategic fits and gain insight on the degree of resilience achieved through the current adaptation steps.

• Design and Prototype of a Train-to-Wayside Communication Architecture
  Johan Bergs, Erwin Van de Velde, Daan Pareit, Dries Naudts, Milos Rovcanin, Ivan De Baere, Walter Van Brussel, Chris Blondia, Ingrid Moerman & Piet Demeester
  Nets4Cars/Nets4Trains 2012, LNCS, Vol. 7266 (To be published), pp. 137-150, Springer-Verlag, A. Vinel and others, 2012.
  The original publication is available at www.springerlink.com
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @inproceedings{bergs12,
  author = {{Johan Bergs} and {Erwin Van de Velde} and {Daan Pareit} and {Dries Naudts} and {Milos Rovcanin} and {Ivan De Baere} and {Walter Van Brussel} and {Chris Blondia} and {Ingrid Moerman} and {Piet Demeester}},
  title = {Design and Prototype of a Train-to-Wayside Communication Architecture},
  booktitle={Nets4Cars/Nets4Trains 2012},
  editor={A. Vinel and others},
  publisher={Springer-Verlag},
  series={{LNCS}},
  volume={7266 (To be published)},
  pages={137-150},
  year={2012},
  abstract = {Telecommunication has become very important in modern society and seems to be almost omnipresent, making daily life easier, more pleasant and connecting people everywhere. It does not only con- nect people, but also machines, enhancing the efficiency of automated tasks and monitoring automated processes. In this context the IBBT (Interdisciplinary Institute for BroadBand Technology) project TRACK (TRain Applications over an advanced Communication networK), sets the definition and prototyping of an end-to-end train-to-wayside commu- nication architecture as one of the main research goals. The architecture provides networking capabilities for train monitoring, personnel appli- cations and passenger Internet services. In the context of the project a prototype framework was developed to give a complete functioning demonstrator. Every aspect: tunneling and mobility, performance en- hancements, and priority and quality of service were taken into consider- ation. In contrast to other research in this area, which has given mostly high-level overviews, TRACK resulted in a detailed architecture with all different elements present.},
  URL={content/publications/2012/nets4trains2012.pdf},
  note={The original publication is available at www.springerlink.com}
  }
  
  Abstract:
  Telecommunication has become very important in modern society and seems to be almost omnipresent, making daily life easier, more pleasant and connecting people everywhere. It does not only con- nect people, but also machines, enhancing the efficiency of automated tasks and monitoring automated processes. In this context the IBBT (Interdisciplinary Institute for BroadBand Technology) project TRACK (TRain Applications over an advanced Communication networK), sets the definition and prototyping of an end-to-end train-to-wayside commu- nication architecture as one of the main research goals. The architecture provides networking capabilities for train monitoring, personnel appli- cations and passenger Internet services. In the context of the project a prototype framework was developed to give a complete functioning demonstrator. Every aspect: tunneling and mobility, performance en- hancements, and priority and quality of service were taken into consider- ation. In contrast to other research in this area, which has given mostly high-level overviews, TRACK resulted in a detailed architecture with all different elements present.

• An Analysis of Requirements to Supporting Mobility in Body Area Networks
  Bart Braem & Chris Blondia
  ICNC 12: 2012 International Conference on Computing, Networking and Communications (ICNC), Maui, USA, pp. 89-94, IEEE Computer Society, 2012.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{bbraem2012ICNC,
  author = {Bart Braem and Chris Blondia},
  title = {An Analysis of Requirements to Supporting Mobility in Body Area Networks},
  booktitle = {ICNC'12: 2012 International Conference on Computing, Networking and Communications (ICNC)},
  publisher = {IEEE Computer Society},
  year = {2012},
  month = {February},
  location = {Maui, USA},
  pages = {89-94},
  URL = {content/publications/2012/bbraem2012ICNC.pdf},
  abstract = {Body Area Networks (BANs) form a strongly growing research field, motivated by increasing need for remote and improved patient healthcare solutions and driven by the development of the IEEE 802.15.6 standard. While most research focuses on single hop star topologies, more studies point towards multi-hop topologies as more preferable. Related with this multi-hop topology however, comes the cost of supporting mobile nodes. Initial research shows the feasibility of adapting protocols to support mobility. This work analyzes two requirements to fulfill mobility support, more specifically location independence and increased clock drifting resiliency. Simulations show the need to fulfill both requirements and motivate that location independence should always be strived for, while clock drift resiliency is shown to be required in larger networks.}
  
  Abstract:
  Body Area Networks (BANs) form a strongly growing research field, motivated by increasing need for remote and improved patient healthcare solutions and driven by the development of the IEEE 802.15.6 standard. While most research focuses on single hop star topologies, more studies point towards multi-hop topologies as more preferable. Related with this multi-hop topology however, comes the cost of supporting mobile nodes. Initial research shows the feasibility of adapting protocols to support mobility. This work analyzes two requirements to fulfill mobility support, more specifically location independence and increased clock drifting resiliency. Simulations show the need to fulfill both requirements and motivate that location independence should always be strived for, while clock drift resiliency is shown to be required in larger networks.

• A novel network architecture for train-to-wayside communication with Quality of Service over heterogeneous wireless networks
  Daan Pareit, Erwin Van de Velde, Dries Naudts, Johan Bergs, Jan Keymeulen, Ivan De Baere, Walter Van Brussel, Christophe Vangeneugden, Patrick Hauspie, Gerd De Vos, Ingrid Moerman, Chris Bondia & Piet Demeester
  EURASIP Journal on Wireless Communications and Networking, No. 114, 2012.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @article{pareit12,
  author = {{Daan Pareit} and {Erwin Van de Velde} and {Dries Naudts} and {Johan Bergs} and {Jan Keymeulen} and {Ivan De Baere} and {Walter Van Brussel} and {Christophe Vangeneugden} and {Patrick Hauspie} and {Gerd De Vos} and {Ingrid Moerman} and {Chris Bondia} and {Piet Demeester}},
  title = {A novel network architecture for train-to-wayside communication with Quality of Service over heterogeneous wireless networks},
  journal = {EURASIP Journal on Wireless Communications and Networking},
  year = {2012},
  number = {114},
  abstract = {In the railway industry, there are nowadays different actors who would like to send or receive data from the wayside to an onboard device or vice versa. These actors are e.g. the Train Operation Company, the Train Constructing Company, a Content Provider, etc. This requires a communication module on each train and at the wayside. These modules interact with each other over heterogeneous wireless links. This system is referred to as the Train-to-Wayside Communication System (TWCS). While there are already a lot of deployments using a TWCS, the implementation of Quality of Service (QoS), Performance Enhancing Proxies (PEP) and the network mobility functions have not yet been fully integrated in TWCS systems. Therefore, we propose a novel and modular IPv6-enabled TWCS architecture in this article. It jointly tackles these functions and considers their mutual dependencies and relationships. DiffServ is used to differentiate between service classes and priorities. Virtual Local Area Networks (VLANs) are used to differentiate between different Service Level Agreements (SLAs). In the PEP, we propose to use a distributed TCP accelerator to optimize bandwidth usage. Concerning net- work mobility, we propose to use the SCTP protocol (with Dynamic Address Reconfiguration and PR-SCTP extensions) to create a tunnel per wireless link, in order to support the reliable transmission of data between the accelerators. We have analyzed different design choices, pinpointed the main implementa- tion challenges and identified candidate solutions for the different modules in the TWCS system. As such, we present an elaborated framework that can be used for prototyping a fully featured TWCS.},
  url = {http://jwcn.eurasipjournals.com/content/pdf/1687-1499-2012-114.pdf}
  }
  
  Abstract:
  In the railway industry, there are nowadays different actors who would like to send or receive data from the wayside to an onboard device or vice versa. These actors are e.g. the Train Operation Company, the Train Constructing Company, a Content Provider, etc. This requires a communication module on each train and at the wayside. These modules interact with each other over heterogeneous wireless links. This system is referred to as the Train-to-Wayside Communication System (TWCS). While there are already a lot of deployments using a TWCS, the implementation of Quality of Service (QoS), Performance Enhancing Proxies (PEP) and the network mobility functions have not yet been fully integrated in TWCS systems. Therefore, we propose a novel and modular IPv6-enabled TWCS architecture in this article. It jointly tackles these functions and considers their mutual dependencies and relationships. DiffServ is used to differentiate between service classes and priorities. Virtual Local Area Networks (VLANs) are used to differentiate between different Service Level Agreements (SLAs). In the PEP, we propose to use a distributed TCP accelerator to optimize bandwidth usage. Concerning net- work mobility, we propose to use the SCTP protocol (with Dynamic Address Reconfiguration and PR-SCTP extensions) to create a tunnel per wireless link, in order to support the reliable transmission of data between the accelerators. We have analyzed different design choices, pinpointed the main implementa- tion challenges and identified candidate solutions for the different modules in the TWCS system. As such, we present an elaborated framework that can be used for prototyping a fully featured TWCS.

• Optimization of WS-BPEL Workflows through Business Process Re-Engineering Patterns
  Jonas Buys, Vincenzo De Florio & Chris Blondia
  Technological Innovations in Adaptive and Dependable Systems: Advancing Models and Concepts, pp. 345-361, IGI Global, Vincenzo De Florio, 2012.
  BibTeX
  
  Bibtex:
  @INBOOK{Buys2012a,
  author = {Jonas Buys and Vincenzo {De Florio} and Chris Blondia},
  editor = {Vincenzo {De Florio}},
  title = {Optimization of WS-BPEL Workflows through Business Process Re-Engineering
  Patterns},
  chapter = {20},
  pages = {345--361},
  year = {2012},
  publisher = {IGI Global},
  isbn = {9781466602557},
  booktitle = {Technological Innovations in Adaptive and Dependable Systems: Advancing
  Models and Concepts},
  doi = {10.4018/978-1-4666-0255-7.ch020}
  }
  
  Abstract:
  Not available

• Signalling minimizing handover parameter optimization algorithm for LTE networks
  Irina-Mihaela Balan, Ingrid Moerman, Bart Sas & Piet Demeester
  WIRELESS NETWORKS, 2012.
  BibTeX | PDF Available
  
  Bibtex:
  @article{balan12,
  author = {{Irina-Mihaela Balan} and {Ingrid Moerman} and {Bart Sas} and {Piet Demeester}},
  title = {Signalling minimizing handover parameter optimization algorithm for LTE networks},
  journal = {WIRELESS NETWORKS},
  year = {2012},
  url={content/publications/2011/balan11signalingminimizinghandovers.pdf}
  }
  
  Abstract:
  Not available

• Technological Innovations in Adaptive and Dependable Systems: Advancing Models and Concepts
  Vincenzo De Florio (editor)
  pp. 475, IGI Global, Vincenzo De Florio, 2012.
  BibTeX | PDF Available
  
  Bibtex:
  @Book{D12,
  editor = {Vincenzo De Florio},
  author = {Vincenzo De Florio (editor)},
  title = {Technological Innovations in Adaptive and Dependable Systems: Advancing Models and Concepts},
  publisher = {IGI Global},
  address = {Hershey, PA 17033, USA},
  year = {2012},
  pages = {475},
  url = {content/publications/2012/TechnologicalInnovationsInAdaptiveAndDependableSystems.pdf}
  }
  
  Abstract:
  Not available

• Robust and Tuneable Family of Gossiping Algorithms
  Vincenzo De Florio & Chris Blondia
  Proceedings of the 20th Euromicro International Conference on Parallel, Distributed, and Network-Based Processing (PDP 2012), Garching, Germany, pp. 154-161, IEEE Comp. Soc., 2012.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{DFB12a,
  author = {Vincenzo De Florio and Chris Blondia},
  title = {Robust and Tuneable Family of Gossiping Algorithms},
  booktitle = {Proceedings of the 20th Euromicro International Conference
  on Parallel, Distributed, and Network-Based Processing (PDP 2012)},
  address = {Garching, Germany},
  location = {Garching, Germany},
  tages = {unknown},
  month = {February},
  day = {15--17},
  year = {2012},
  pages = {154--161},
  url = {content/publications/2012/pdp12.pdf},
  publisher = {IEEE Comp. Soc.},
  abstract = {We present a family of gossiping algorithms whose members share the same
  structure though they vary their performance in function of a combinatorial parameter.
  We show that such parameter may be considered as a ``knob'' controlling
  the amount of communication parallelism characterizing the algorithms.
  After this we introduce procedures to operate the knob and choose parameters
  matching the amount of communication channels currently
  provided by the available communication system(s). In so doing we
  provide a robust mechanism to tune the production of requests for communication
  after the current operational conditions of the consumers of such
  requests. This can be used to achieve high performance
  and programmatic avoidance of undesirable events such as message collisions.},
  }
  
  Abstract:
  We present a family of gossiping algorithms whose members share the same though they vary their performance in function of a combinatorial parameter. show that such parameter may be considered as a knob controlling amount of communication parallelism characterizing the algorithms. this we introduce procedures to operate the knob and choose parameters the amount of communication channels currently by the available communication system(s). In so doing we a robust mechanism to tune the production of requests for communication the current operational conditions of the consumers of such This can be used to achieve high performance and programmatic avoidance of undesirable events such as message collisions.

2011

• Load Balancing and the power of preventive probing
  B. Van Houdt
  Performance Evaluation Review, Vol. 39, No. 2, pp. 65-67, 2011.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{perf11,
  author = {B. Van Houdt},
  title = {Load Balancing and the power of preventive probing},
  booktitle = {Performance Evaluation Review},
  volume = {39},
  number = {2},
  pages = {65-67},
  year = {2011},
  URL = {content/publications/2011/Perf2011.pdf}
  }
  
  Abstract:
  Not available

• An analytical model to study the impact of time-varying cell capacity in LTE networks
  Bart Sas, Elena Bernal-Mor, Kathleen Spaey, Vicent Pla, Chris Blondia & Jorge Martinez-Bauset
  Proceedings of the 4th Joint IFIP Wireless and Mobile Networking Conference (WMNC), 2011.
  BibTeX | PDF Available
  
  Bibtex:
  @inproceedings{sas11,
  author = {{Bart Sas} and {Elena Bernal-Mor} and {Kathleen Spaey} and {Vicent Pla} and {Chris Blondia} and {Jorge Martinez-Bauset}},
  title = {An analytical model to study the impact of time-varying cell capacity in LTE networks},
  booktitle = {Proceedings of the 4th Joint IFIP Wireless and Mobile Networking Conference (WMNC)},
  year = {2011},
  month = {October}
  URL = {content/publications/2011/sas11varyingcellcapacity.pdf}
  }
  
  Abstract:
  Not available

• Data traffic differentiation and QoS on the train, in fast parameter varying, heterogeneous wireless networks
  Milos Rovcanin, Daan Pareit, Dries Naudts, Erwin Van de Velde, Johan Bergs, Ingrid Moerman & Chris Blondia
  18th IEEE Symposium on Communications and Vehicular Technology in the Benelux, Ghent, Belgium, 2011.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{bergsvdv2011SCVT,
  author = { Milos Rovcanin and Daan Pareit and Dries Naudts and Erwin Van de Velde and Johan Bergs and Ingrid Moerman and Chris Blondia},
  title = {Data traffic differentiation and QoS on the train, in fast parameter varying, heterogeneous wireless networks},
  booktitle = {18th IEEE Symposium on Communications and Vehicular Technology in the Benelux},
  year = {2011},
  month = {November},
  location = {Ghent, Belgium},
  URL = {content/publications/2011/bergsvdv2011SCVT.pdf}
  abstract={Although Internet on the train and train to wayside communication in general becomes more and more available for train operators, there are still a lot of challenges for future research. We previously developed a network platform that is responsible for an uninterrupted and seamless connectivity from the train to the wayside through heterogeneous wireless access technologies. This paper mainly focuses on the concept for providing sufficient Quality of Service (QoS) guarantees in a dynamic train environment. Within this network platform, IPv6 strategies are adopted for QoS, exploiting multi-homing and intelligent aggregation techniques. The implementation that has been done in the Click Modular Router programming environment will also be presented in details.}
  
  Abstract:
  Although Internet on the train and train to wayside communication in general becomes more and more available for train operators, there are still a lot of challenges for future research. We previously developed a network platform that is responsible for an uninterrupted and seamless connectivity from the train to the wayside through heterogeneous wireless access technologies. This paper mainly focuses on the concept for providing sufficient Quality of Service (QoS) guarantees in a dynamic train environment. Within this network platform, IPv6 strategies are adopted for QoS, exploiting multi-homing and intelligent aggregation techniques. The implementation that has been done in the Click Modular Router programming environment will also be presented in details.

• Supporting Mobility in Wireless Body Area Networks: an Analysis
  Bart Braem & Chris Blondia
  invited paper at 18th IEEE Symposium on Communications and Vehicular Technology in the Benelux, Ghent, Belgium, 2011.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{bbraem2011SCVT,
  author = { Bart Braem and Chris Blondia},
  title = {Supporting Mobility in Wireless Body Area Networks: an Analysis},
  booktitle = {invited paper at 18th IEEE Symposium on Communications and Vehicular Technology in the Benelux},
  year = {2011},
  month = {November},
  location = {Ghent, Belgium},
  URL = {content/publications/2011/bbraem2011SCVT.pdf},
  abstract = {In a world with a growing elderly population, Wireless Body Area Networks (WBANs) are considered an opportunity to supply healthcare to a growing number of patients requiring continuous medical care. A large number of WBAN sensors, radios, medium access and routing protocols have already been developed and is actively being developed. Together with an increasing number of applications and field trials, this illustrates how promising WBANs are, both to academia and industry.
  Currently, WBANs are almost always assumed to have a singlehop topology, where all nodes on the body are in range of the central sink device. However, to conserve energy and to limit exposure of the human body to radiation, research indicates the need to support multi-hop topologies. In those small-scale topologies, a small body movement can cause a complete topology reorganization or more general node mobility.
  This work analyzes three algorithm variants to support these mobile WBANs, with respect to channel utilization and energy efficiency, in both a static and a mobile scenario.}
  
  Abstract:
  In a world with a growing elderly population, Wireless Body Area Networks (WBANs) are considered an opportunity to supply healthcare to a growing number of patients requiring continuous medical care. A large number of WBAN sensors, radios, medium access and routing protocols have already been developed and is actively being developed. Together with an increasing number of applications and field trials, this illustrates how promising WBANs are, both to academia and industry. WBANs are almost always assumed to have a singlehop topology, where all nodes on the body are in range of the central sink device. However, to conserve energy and to limit exposure of the human body to radiation, research indicates the need to support multi-hop topologies. In those small-scale topologies, a small body movement can cause a complete topology reorganization or more general node mobility. work analyzes three algorithm variants to support these mobile WBANs, with respect to channel utilization and energy efficiency, in both a static and a mobile scenario.

• An enhanced weighted performance based handover parameter optimization algorithm for LTE networks
  Irina Mihaela Balan, Bart Sas, Thomas Jansen, I. Moerman, Kathleen Spaey & Piet Demeester
  EURASIP Journal on Wireless Communications and Networking, No. EURASIP JWCN/858631, 2011.
  BibTeX | PDF Available
  
  Bibtex:
  @article{balan11-2,
  author = {{Irina Mihaela Balan} and {Bart Sas} and {Thomas Jansen} and {I. Moerman} and {Kathleen Spaey} and {Piet Demeester}},
  title = {An enhanced weighted performance based handover parameter optimization algorithm for LTE networks},
  journal = {EURASIP Journal on Wireless Communications and Networking},
  year = {2011},
  number = {EURASIP JWCN/858631},
  month = {February},
  url = {content/publications/2011/balan11enhancedparameteroptimization.pdf}
  }
  
  Abstract:
  Not available

• Enhanced Weighted Performance based Handover Optimization in LTE
  Irina Balan, Thomas Jansen, Bart Sas, Ingrid Moerman & Thomas Kürner
  Future Network and MobileSummit 2011 Conference Proceedings, IIMC International Information Management Corporation, Paul Cunningham and Miriam Cunningham, 2011.
  BibTeX | PDF Available
  
  Bibtex:
  @inproceedings{balan11,
  author = {{Irina Balan} and {Thomas Jansen} and {Bart Sas} and {Ingrid Moerman} and {Thomas K{\"u}rner}},
  title = {Enhanced Weighted Performance based Handover Optimization in LTE},
  booktitle = {Future Network and MobileSummit 2011 Conference Proceedings},
  year = {2011},
  editor = {{Paul Cunningham} and {Miriam Cunningham}},
  organization = {IIMC International Information Management Corporation},
  publisher = {IIMC International Information Management Corporation},
  month = {June},
  url = {content/publications/2011/balan11enhancedweightedhandover.pdf}
  }
  
  Abstract:
  Not available

• Models for wireless data communications in indoor train environment
  Luc Verstrepen, Wout Joseph, Emmeric Tanghe, Daan Pareit, Dries Naudts, Jan Keymeulen, Peter De Cleyn, Chris Blondia, Luc Martens & Ingrid Moerman
  Accepted in Wireless Personal Communications, 2011.
  BibTeX
  
  Bibtex:
  @article{decleyn2011,
  author = {Luc Verstrepen and Wout Joseph and Emmeric Tanghe and Daan Pareit and Dries Naudts and Jan Keymeulen and Peter De Cleyn and Chris Blondia and Luc Martens and Ingrid Moerman},
  title = {Models for wireless data communications in indoor train environment},
  journal = {Accepted in Wireless Personal Communications},
  year = {2011}
  }
  
  Abstract:
  Not available

• The effect of Partial Conversion and Fiber Delay Lines in an OBS switch with a large number of wavelengths
  J.F. Perez & B. Van Houdt
  Photonic Network Communications, Vol. 21, No. 1, pp. 64-77, 2011.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{pnet,
  author = {J.F. Perez and B. Van Houdt},
  title = {The effect of Partial Conversion and Fiber Delay Lines in an OBS switch with a large number of wavelengths},
  booktitle = {Photonic Network Communications},
  volume = {21},
  number = {1},
  pages = {64-77},
  year = {2011},
  URL = {content/publications/2011/PerezVanHoudt_PhotonicNetwork_2011.pdf}
  }
  
  Abstract:
  Not available

• Quasi-Birth-and-Death processes with restricted transitions and its applications
  J.F. Perez & B. Van Houdt
  Performance Evaluation, Vol. 68, No. 3, pp. 126-141, 2011.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{peis,
  author = {J.F. Perez and B. Van Houdt},
  title = {Quasi-Birth-and-Death processes with restricted transitions and its applications },
  booktitle = {Performance Evaluation},
  volume = {68},
  number = {3},
  pages = {126-141},
  year = {2011},
  URL = {content/publications/2011/PEVA2011QEST.pdf}
  }
  
  Abstract:
  Not available

• The M/G/1-type Markov chain with restricted transitions and its application to queues with batch arrivals
  J.F. Perez & B. Van Houdt
  Probability in the Engineering and Informational Sciences, Vol. 25, No. 4, pp. 487-517, 2011.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{peis,
  author = {J.F. Perez and B. Van Houdt},
  title = {The M/G/1-type Markov chain with restricted transitions and its application to queues with batch arrivals},
  booktitle = {Probability in the Engineering and Informational Sciences},
  volume = {25},
  number = {4},
  pages = {487-517},
  year = {2011},
  URL = {content/publications/2011/PerezVanHoudtPEIS.pdf}
  }
  
  Abstract:
  Not available

• Triangular M/G/1-type and tree-like QBD Markov chains
  B. Van Houdt & J. S.H. van Leeuwaarden
  INFORMS Journal on Computing, Vol. 23, No. 1, pp. 165-171, 2011.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{total,
  author = {B. Van Houdt and J. S.H. van Leeuwaarden},
  title = {Triangular M/G/1-type and tree-like QBD Markov chains},
  booktitle = {INFORMS Journal on Computing},
  volume = {23},
  number = {1},
  pages = {165-171},
  year = {2011},
  URL = {content/publications/2011/INFORMS2011.pdf}
  }
  
  Abstract:
  Not available

• Performance Comparison of Aggressive Push and Traditional Pull Strategies in Large Distributed Systems
  B. Van Houdt
  Proceedings of QEST 2011, Aachen, Germany, pp. 265-274, 2011.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{dagstuhl,
  author = {B. Van Houdt},
  title = Performance Comparison of Aggressive Push and Traditional Pull Strategies in Large Distributed Systems},
  booktitle = {Proceedings of QEST 2011},
  pages = {265-274},
  year = {2011},
  month = {SEPT},
  location = {Aachen, Germany},
  URL = {content/publications/2011/CRC_Pullpush.pdf}
  }
  
  Abstract:
  Not available

• Robust-and-evolvable Resilient Software Systems: Open Problems and Lessons Learned
  Vincenzo De Florio
  Proceedings of the ESEC/FSE 2011 Workshop on Assurances for Self-Adaptive Systems (ASAS 2011), ACM, 2011.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{DF11b,
  author = {Vincenzo De Florio},
  title = {Robust-and-evolvable Resilient Software Systems: Open Problems and Lessons Learned},
  booktitle = {Proceedings of the ESEC/FSE 2011 Workshop on Assurances for Self-Adaptive Systems (ASAS 2011)},
  address = {Szeged, Hungary},
  tages = {594--607},
  month = {September},
  publisher = {ACM},
  year = {2011},
  day = {4},
  abstract = {How to build robust-and-evolvable resilient software systems? On the one hand, evolvability implies a system’s
  ability to reach autonomously new, possibly unprecedented
  conditions and states; on the other hand, resilience and robustness refer to feature persistence in the face of perturbations and changes such as the ones brought about by system
  evolution. How to address such problem? How to make sure
  that a software system shall exhibit emerging properties such
  as reliability or safety irrespective of its environmental conditions and whatever its new configuration may be? In this
  paper we discuss these problems leveraging from three cases
  of adaptive software and systems designs. Our conclusions
  are that the complexity and characteristics of the system
  components in control of evolution as well as the forms of
  interaction of the systems with their environments play a
  key role in the ultimate emergence of sought properties and
  behaviours. Moreover we highlight how social eco-systems
  in heterarchical organisation appear to have a stronger resilience and robustness throughout their evolutions.},
  url={content/publications/2011/asas13d-deflorio.pdf}
  }
  
  Abstract:
  How to build robust-and-evolvable resilient software systems? On the one hand, evolvability implies a system’s to reach autonomously new, possibly unprecedented and states; on the other hand, resilience and robustness refer to feature persistence in the face of perturbations and changes such as the ones brought about by system How to address such problem? How to make sure a software system shall exhibit emerging properties such reliability or safety irrespective of its environmental conditions and whatever its new configuration may be? In this we discuss these problems leveraging from three cases adaptive software and systems designs. Our conclusions that the complexity and characteristics of the system in control of evolution as well as the forms of of the systems with their environments play a role in the ultimate emergence of sought properties and Moreover we highlight how social eco-systems in heterarchical organisation appear to have a stronger resilience and robustness throughout their evolutions.

• Trading off Complexity for Expressiveness in Programming Languages for Embedded Devices: Visions and Experiences
  Vincenzo De Florio & Chris Blondia
  Proceedings of the 3rd International Conference on Advanced Communication and Networking (ACN 2011), Springer, 2011.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{DFB11b,
  author = {Vincenzo De Florio and Chris Blondia},
  title = {Trading off Complexity for Expressiveness in Programming Languages for Embedded Devices: Visions and Experiences},
  booktitle = {Proceedings of the 3rd International Conference on Advanced Communication and Networking (ACN 2011)},
  address = {Brno University, Czech Republic},
  tages = {594--607},
  month = {August},
  year = {2011},
  publisher = {Springer},
  abstract = {When programming resource-scarce embedded smart devices
  the designer requires both the low-level system programming features of
  a language such as C and higher level capability typical of a language like
  Java. The choice of a particular language often implies trade offs between
  conflicting design goals such as performance, costs, time-to-market, and
  overheads. The large variety of languages, virtual machines, and translators provides the designer with a dense trade off space, ranging from
  minimalistic to rich full-fledged approaches, but once a choice is made it
  is often difficult and tricky for the designer to revise it. In this work we
  propose a different approach based on the principles of language-oriented
  programming. A system of light-weighted and modular extensions is proposed as a method to adaptively reshape the target programming language as needed, adding only those application layer features that match
  the current design goals. By doing so complexity is made transparent,
  but not hidden: While the programmer can benefit from higher level
  constructs, the designer and the deployer can deal with modular building blocks each characterized by a certain algorithmic complexity and
  therefore each accountable for a given share of the overhead. As a result
  the designer is provided with finer control on the amount of computing
  resources that are consumed by the run-time executive of the chosen
  programming language.},
  URL = {content/publications/2011/acn11.pdf}
  }
  
  Abstract:
  When programming resource-scarce embedded smart devices designer requires both the low-level system programming features of language such as C and higher level capability typical of a language like The choice of a particular language often implies trade offs between design goals such as performance, costs, time-to-market, and The large variety of languages, virtual machines, and translators provides the designer with a dense trade off space, ranging from to rich full-fledged approaches, but once a choice is made it often difficult and tricky for the designer to revise it. In this work we a different approach based on the principles of language-oriented A system of light-weighted and modular extensions is proposed as a method to adaptively reshape the target programming language as needed, adding only those application layer features that match current design goals. By doing so complexity is made transparent, not hidden: While the programmer can benefit from higher level the designer and the deployer can deal with modular building blocks each characterized by a certain algorithmic complexity and each accountable for a given share of the overhead. As a result designer is provided with finer control on the amount of computing that are consumed by the run-time executive of the chosen programming language.

• On the Effects of Interference between Heterogeneous Sensor Network MAC Protocols
  Daniel van den Akker, Bart Braem & Chris Blondia
  Mobile Ad-Hoc and Sensor Systems, IEEE International Conference on, Vol. 0, pp. 560-569, IEEE Computer Society, 2011.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @article{10.1109/MASS.2011.59,
  author = {Daniel van den Akker and Bart Braem and Chris Blondia},
  title = {On the Effects of Interference between Heterogeneous Sensor Network MAC Protocols},
  journal ={Mobile Ad-Hoc and Sensor Systems, IEEE International Conference on},
  volume = {0},
  isbn = {978-0-7695-4469-4},
  year = {2011},
  pages = {560-569},
  doi = {http://doi.ieeecomputersociety.org/10.1109/MASS.2011.59},
  publisher = {IEEE Computer Society},
  address = {Los Alamitos, CA, USA},
  URL = {content/publications/2011/dvdakker2011hetMACint.pdf},
  abstract = {The growing popularity of sensor networks
  has resulted in the creation of various MAC protocols,
  each optimized for a different set of application requirements.
  However, all of these heterogeneous MAC
  protocols are designed under the assumption that all
  nodes in the wireless environment use a common MAC
  protocol. When multiple sensor networks are deployed
  in the same wireless environment, this assumption no
  longer holds since different sensor networks will most
  likely make use of different MAC protocols. This paper
  investigates the effect of interference between sensor
  networks using heterogeneous MAC protocols, based on
  the network performance of these sensor networks. The
  network performance of TDMA, CSMA/CA, T-MAC and
  LPL-MAC, a variant of B-MAC, is examined. Test results
  show that depending on the interfering MAC protocol,
  the amount of interference and the load of the network,
  the average energy consumption can increase by 17%
  for contention-based protocols and 62% for TDMA based
  protocols. Moreover this interference can cause the endto-
  end data loss to more than double for contention-based
  protocols while for TDMA protocols the end-to-end data
  loss can increase from 0.1% to more than 40%.}
  
  Abstract:
  The growing popularity of sensor networks resulted in the creation of various MAC protocols, optimized for a different set of application requirements. all of these heterogeneous MAC are designed under the assumption that all in the wireless environment use a common MAC When multiple sensor networks are deployed the same wireless environment, this assumption no holds since different sensor networks will most make use of different MAC protocols. This paper the effect of interference between sensor using heterogeneous MAC protocols, based on network performance of these sensor networks. The performance of TDMA, CSMA/CA, T-MAC and a variant of B-MAC, is examined. Test results that depending on the interfering MAC protocol, amount of interference and the load of the network, average energy consumption can increase by 17% contention-based protocols and 62% for TDMA based Moreover this interference can cause the endto- data loss to more than double for contention-based while for TDMA protocols the end-to-end data can increase from 0.1% to more than 40%.

• Bonded deficit round robin scheduling for multi-channel networks
  Dessislava Nikolova & Chris Blondia
  Computer Networks, Vol. 55, No. 15, pp. 3503 - 3516, Elsevier, 2011.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @article{dessie2011cn,
  author = {Dessislava Nikolova and Chris Blondia},
  title = {Bonded deficit round robin scheduling for multi-channel networks},
  journal = {Computer Networks},
  publisher = {Elsevier},
  volume = {55},
  number = {15},
  pages = {3503 - 3516},
  year = {2011},
  issn = {1389-1286},
  URL = {content/publications/2011/dessie2011cn.pdf},
  doi = {DOI: 10.1016/j.comnet.2011.07.007},
  abstract = {In order to increase the link capacity in telecommunication networks the bandwidth of multiple channels can be aggregated by transmitting on them simultaneously. The latest data-over-cable service interface specification (DOCSIS 3.0) for hybrid fiber coax networks defines a mechanism for channel bonding at the link layer. Thus, the scheduler at the cable modem termination system, which distributes the packets on the network, not only has to support per-flow queuing but also has to distribute the packets to one modem over possibly several channels.
  In this article we propose two downstream multi-channel packet scheduling algorithms designed to support scheduling amongst flows possibly using different numbers of channels. Both algorithms are based on the deficit round robin (DRR) scheduler. The bonded deficit round robin (BDRR) algorithm, has complexity dependent only on the number of the channels and requires only one queue per flow. It is shown that the algorithm is a latency-rate server and the latency is derived. Furthermore, BDRR bounds the packet reordering and the maximum bounds on the packet delay and the reorder buffer needed at the receiver are calculated. The paper explores also a second algorithm which has more similarities with load balancing algorithms. It uses fully independent channel schedulers thus avoiding the need for modification in the single channel DRR algorithm. The transmission channel for a packet is selected upon its arrival. However, the algorithm does not bound the latency and packet reorder for flows assigned to receive on multiple channels. Flows for which such bound is needed should be assigned on a single channel.}
  }
  }
  
  Abstract:
  In order to increase the link capacity in telecommunication networks the bandwidth of multiple channels can be aggregated by transmitting on them simultaneously. The latest data-over-cable service interface specification (DOCSIS 3.0) for hybrid fiber coax networks defines a mechanism for channel bonding at the link layer. Thus, the scheduler at the cable modem termination system, which distributes the packets on the network, not only has to support per-flow queuing but also has to distribute the packets to one modem over possibly several channels. this article we propose two downstream multi-channel packet scheduling algorithms designed to support scheduling amongst flows possibly using different numbers of channels. Both algorithms are based on the deficit round robin (DRR) scheduler. The bonded deficit round robin (BDRR) algorithm, has complexity dependent only on the number of the channels and requires only one queue per flow. It is shown that the algorithm is a latency-rate server and the latency is derived. Furthermore, BDRR bounds the packet reordering and the maximum bounds on the packet delay and the reorder buffer needed at the receiver are calculated. The paper explores also a second algorithm which has more similarities with load balancing algorithms. It uses fully independent channel schedulers thus avoiding the need for modification in the single channel DRR algorithm. The transmission channel for a packet is selected upon its arrival. However, the algorithm does not bound the latency and packet reorder for flows assigned to receive on multiple channels. Flows for which such bound is needed should be assigned on a single channel.

• Self-optimisation of admission control and handover parameters in LTE
  Bart Sas, Kathleen Spaey, Irina Balan, Kristina Zetterberg & Remco Litjens
  2011 IEEE 73rd Vehicular Technology Conference, 2011.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{
  author = {Bart Sas and Kathleen Spaey and Irina Balan and Kristina Zetterberg and Remco Litjens},
  title = {Self-optimisation of admission control and handover parameters in LTE},
  booktitle = {2011 IEEE 73rd Vehicular Technology Conference},
  year = {2011},
  month = {May},
  abstract = {In mobile cellular networks the handover (HO) algorithm is responsible for determining when calls of users that are moving from one cell to another are handed over from the former to the latter. The admission control (AC) algorithm, which is the algorithm that decides whether new (fresh or HO) calls that enter a cell are allowed to the cell or not, often tries to facilitate HO by prioritising HO calls in favour of fresh calls. In this way, a good quality of service (QoS) for calls that are already admitted to the network is pursued. In this paper, the effect of self-optimisation of AC parameters on the HO performance in a long term evolution (LTE) network is studied, both with and without the self-optimisation of HO parameters. Simulation results show that the AC parameter optimisation algorithm considerably improves the HO performance by reducing the amount of calls that are dropped prior to or during HO.}
  url={content/publications/2011/sas11selfoptimisationac.pdf}
  }
  
  Abstract:
  In mobile cellular networks the handover (HO) algorithm is responsible for determining when calls of users that are moving from one cell to another are handed over from the former to the latter. The admission control (AC) algorithm, which is the algorithm that decides whether new (fresh or HO) calls that enter a cell are allowed to the cell or not, often tries to facilitate HO by prioritising HO calls in favour of fresh calls. In this way, a good quality of service (QoS) for calls that are already admitted to the network is pursued. In this paper, the effect of self-optimisation of AC parameters on the HO performance in a long term evolution (LTE) network is studied, both with and without the self-optimisation of HO parameters. Simulation results show that the AC parameter optimisation algorithm considerably improves the HO performance by reducing the amount of calls that are dropped prior to or during HO.

• Analysis of TDMA scheduling by means of Egyptian Fractions for real-time WSNs
  Wim Torfs & Chris Blondia
  EURASIP Journal on Wireless Communications and Networking 2011, 2011.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{
  author = {Wim Torfs and Chris Blondia},
  title = {Analysis of TDMA scheduling by means of Egyptian Fractions for real-time WSNs},
  booktitle = {EURASIP Journal on Wireless Communications and Networking 2011},
  year = {2011},
  month = {JUL},
  url = {content/publications/2011/wtorfs_blondia_1687-1499-2011-37.pdf},
  abstract = {In Wireless Sensor Networks (WSNs), Time Division Multiple Access (TDMA) is a well-studied subject. TDMA has, however, the reputation of being a rigid access method and many TDMA protocols have issues regarding the entering or leaving of sensors or have a predetermined upper limit on the number of nodes in the network. In this article, we present a flexible TDMA access method for passive sensors, that is, sensors that are constant bitrate sources. The presented protocol poses no bounds on the number of nodes, yet provides a stable framing that ensures proper operation, while it fosters that every sensor gets its data on time at the sink and this in a fair fashion. Even more, the latency of the transmission is deterministic and thereby enabling real-time communication. The protocol is developed, keeping in mind the practical limitations of actual hardware, limiting the memory usage and the communication overhead. The schedule that determines when a sensor can send can be encoded in a very small footprint and needs to be sent only once. As soon as the sensor has received its schedule, it can calculate for the rest of its lifetime when it is allowed to send.}
  }
  
  Abstract:
  In Wireless Sensor Networks (WSNs), Time Division Multiple Access (TDMA) is a well-studied subject. TDMA has, however, the reputation of being a rigid access method and many TDMA protocols have issues regarding the entering or leaving of sensors or have a predetermined upper limit on the number of nodes in the network. In this article, we present a flexible TDMA access method for passive sensors, that is, sensors that are constant bitrate sources. The presented protocol poses no bounds on the number of nodes, yet provides a stable framing that ensures proper operation, while it fosters that every sensor gets its data on time at the sink and this in a fair fashion. Even more, the latency of the transmission is deterministic and thereby enabling real-time communication. The protocol is developed, keeping in mind the practical limitations of actual hardware, limiting the memory usage and the communication overhead. The schedule that determines when a sensor can send can be encoded in a very small footprint and needs to be sent only once. As soon as the sensor has received its schedule, it can calculate for the rest of its lifetime when it is allowed to send.

• Towards Context-Aware Adaptive Fault Tolerance in SOA Applications
  Jonas Buys, Vincenzo De Florio & Chris Blondia
  Proceedings of the 5th ACM International Conference on Distributed Event-Based Systems (DEBS), New York, USA, pp. 63-74, Association for Computing Machinery, Inc. (ACM), 2011.
  BibTeX | PDF Available | Presentation
  
  Bibtex:
  @INPROCEEDINGS{Buys2011,
  author = {Jonas Buys and Vincenzo {De Florio} and Chris Blondia},
  title = {Towards Context-Aware Adaptive Fault Tolerance in SOA Applications},
  booktitle = {Proceedings of the 5th ACM International Conference on Distributed Event-Based Systems (DEBS)},
  year = {2011},
  publisher = {Association for Computing Machinery, Inc. (ACM)},
  location = {New York, USA},
  pages = {63--74},
  doi = {http://dx.doi.org/10.1145/2002259.2002271},
  url = {http://dl.acm.org/authorize?448355},
  presentation = {http://euterpe.cmi.ua.ac.be/~jbuys/presentations/debs2011-jb.ppt}
  }
  
  Abstract:
  Not available

• IMEC Academy / SSET seminar Cost-effective software reliability through autonomic tuning of system resources
  Vincenzo De Florio
  IMEC Academy series, IMEC, Leuven, Belgium, 2011.
  Available online through "http://mediasite.imec.be/mediasite/SilverlightPlayer/Default.aspx?peid" "a66bb1768e184e86b5965b13ad24b7dd"
  BibTeX | Abstract | Presentation
  
  Bibtex:
  @Misc{De11IMEC,
  author = {Vincenzo De Florio},
  title = {IMEC Academy / SSET seminar Cost-effective software reliability through autonomic tuning of system resources},
  booktitle = {IMEC Academy series},
  location = {IMEC, Leuven, Belgium},
  year = {2011},
  month = {May},
  day = {4},
  presentation = {http://mediasite.imec.be/mediasite/SilverlightPlayer/Default.aspx?peid=a66bb1768e184e86b5965b13ad24b7dd},
  note = {Available online through "http://mediasite.imec.be/mediasite/SilverlightPlayer/Default.aspx?peid" = "a66bb1768e184e86b5965b13ad24b7dd"},
  abstract = {Often the systems our societies depend upon are built in such a way as to result too inflexible and intolerant to changes. The deployment of such systems in environments where change is the rule rather than the exception leads to situations where reliability and performance are strongly and negatively affected. In particular, upper bounds and worst-case analyses do not match those environments. Truly effective software reliability approaches require a precise characterization of the allocation of resources over time. In other words, unwanted emergent behaviors can only be avoided if the systems are built with a finer-grained control of the redundancy degree. Here we discuss this problem, summarize the lessons we learned by investigating it, and provide an example of a compliant system - adaptively redundant data structures. We show in particular how such systems allow software reliability to be guaranteed cost-effectively through autonomic tuning of the employed redundancy. Available online through mediasite.imec.be/mediasite/SilverlightPlayer/Default.aspx?peid=a66bb1768e184e86b5965b13ad24b7dd},
  }
  
  Abstract:
  Often the systems our societies depend upon are built in such a way as to result too inflexible and intolerant to changes. The deployment of such systems in environments where change is the rule rather than the exception leads to situations where reliability and performance are strongly and negatively affected. In particular, upper bounds and worst-case analyses do not match those environments. Truly effective software reliability approaches require a precise characterization of the allocation of resources over time. In other words, unwanted emergent behaviors can only be avoided if the systems are built with a finer-grained control of the redundancy degree. Here we discuss this problem, summarize the lessons we learned by investigating it, and provide an example of a compliant system - adaptively redundant data structures. We show in particular how such systems allow software reliability to be guaranteed cost-effectively through autonomic tuning of the employed redundancy. Available online through mediasite.imec.be/mediasite/SilverlightPlayer/Default.aspx?peida66bb1768e184e86b5965b13ad24b7dd,

• System Structure for Dependable Software Systems
  Vincenzo De Florio & Chris Blondia
  Proceedings of the 11th International Conference on Computational Science and Its Applications (ICCSA 2011), Lecture Notes in Computer Science vol.6784, 2011.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{DFB11a,
  author = {Vincenzo De Florio and Chris Blondia},
  title = {System Structure for Dependable Software Systems},
  booktitle = {Proceedings of the 11th International Conference on Computational Science and Its Applications (ICCSA 2011), Lecture Notes in Computer Science vol.6784},
  address = {Santander, Spain},
  tages = {594--607},
  month = {June},
  year = {2011},
  abstract = {Truly dependable software systems should be built with structuring techniques able to decompose the software complexity without hiding important hypotheses and assumptions such as those regarding their
  target execution environment and the expected fault- and system models.
  A judicious assessment of what can be made transparent and what should
  be translucent is necessary. This paper discusses a practical example of a
  structuring technique built with these principles in mind: Reflective and
  refractive variables. We show that our technique offers an acceptable degree of separation of the design concerns, with limited code intrusion; at
  the same time, by construction, it separates but does not hide the complexity required for managing fault-tolerance. In particular, our technique
  offers access to collected system-wide information and the knowledge extracted from that information. This can be used to devise architectures
  that minimize the hazard of a mismatch between dependable software and
  the target execution environments.},
  URL = {content/publications/2011/sepa11.pdf}
  }
  
  Abstract:
  Truly dependable software systems should be built with structuring techniques able to decompose the software complexity without hiding important hypotheses and assumptions such as those regarding their execution environment and the expected fault- and system models. judicious assessment of what can be made transparent and what should translucent is necessary. This paper discusses a practical example of a technique built with these principles in mind: Reflective and variables. We show that our technique offers an acceptable degree of separation of the design concerns, with limited code intrusion; at same time, by construction, it separates but does not hide the complexity required for managing fault-tolerance. In particular, our technique access to collected system-wide information and the knowledge extracted from that information. This can be used to devise architectures minimize the hazard of a mismatch between dependable software and the target execution environments.

• Design of Energy Efficient Topologies for Wireless On-Body Channel
  Wout Joseph, Bart Braem, Elisabeth Reusens, Benoît Latré, Luc Martens & Chris Blondia
  invited at 17th European Wireless Conference, Vienna, Austria, pp. 82-88, IEEE Computer Society, 2011.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{bbraem2011europeanwireless,
  author = {Wout Joseph and Bart Braem and Elisabeth Reusens and Beno{\^i}t Latr{\'e} and Luc Martens and Chris Blondia},
  title = {Design of Energy Efficient Topologies for Wireless On-Body Channel},
  booktitle = {invited at 17th European Wireless Conference},
  abstract = {Advanced applications in the area of remote health monitoring can be realized by Wireless Body Area Networks (WBANs). This paper investigates the physical propagation channel at 2.45 GHz near real humans and presents an ap- plication for cross-layer design in order to optimize the energy consumption of single-hop and multi-hop network topologies. The characterization of the physical layer is an important element in the development of a WBAN. Propagation measurements are performed on real humans in a multipath environment and propagation models are proposed. As a cross-layer application, the proposed path loss models are used to evaluate the energy efficiency of different network topologies. The paper investigates which topology is the most energy efficient in WBANs: single-hop or multi-hop communication.},
  location = {Vienna, Austria},
  publisher={IEEE Computer Society},
  pages = {82-88},
  month={april}
  year={2011},
  url={content/publications/2011/bbraemEWSN11.pdf}
  }
  
  Abstract:
  Advanced applications in the area of remote health monitoring can be realized by Wireless Body Area Networks (WBANs). This paper investigates the physical propagation channel at 2.45 GHz near real humans and presents an ap- plication for cross-layer design in order to optimize the energy consumption of single-hop and multi-hop network topologies. The characterization of the physical layer is an important element in the development of a WBAN. Propagation measurements are performed on real humans in a multipath environment and propagation models are proposed. As a cross-layer application, the proposed path loss models are used to evaluate the energy efficiency of different network topologies. The paper investigates which topology is the most energy efficient in WBANs: single-hop or multi-hop communication.

• Run-time Compositional Software Platform for Autonomous NXT Robots
  Ning Gui, Vincenzo De Florio & Chris Blondia
  International Journal of Adaptive, Resilient and Autonomic Systems, special ADAMUS issue, Vol. 2, No. 2, Marcello Cinque and Tim Stevens, Editors, 2011.
  BibTeX | PDF Available
  
  Bibtex:
  @Article{GDeB11a,
  author = {Ning Gui and Vincenzo De Florio and Chris Blondia},
  title = {Run-time Compositional Software Platform for Autonomous NXT Robots},
  journal = {International Journal of Adaptive, Resilient and Autonomic Systems, special ADAMUS issue},
  editor = {Marcello Cinque and Tim Stevens, Editors},
  volume = {2},
  number = {2},
  month = {April},
  year = {2011},
  url = {content/publications/2011/ijaras11ning1.pdf}
  }
  
  Abstract:
  Not available

• Toward Architecture-based Context-Aware Deployment and Adaptation
  Ning Gui , Vincenzo De Florio & Chris Blondia
  Journal of Systems and Software, Vol. 84, Elsevier, 2011.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{GDFB11a,
  author = {Ning Gui and Vincenzo De Florio and Chris Blondia},
  title = {Toward Architecture-based Context-Aware Deployment and Adaptation},
  journal = {Journal of Systems and Software},
  year = {2011},
  volume = {84},
  tages = {185--197},
  publisher = {Elsevier},
  URL = {content/publications/2011/accadajss.pdf}
  }
  
  Abstract:
  Not available

• Software Assumptions Failure Tolerance: Role, Strategies, and Visions
  Vincenzo De Florio
  Chapter in Architecting Dependable Systems, Vol. 7, (Antonio Casimiro, Rogério de Lemos, and Cristina Gacek, Eds.), Lecture Notes in Computer Science, Vol. 6420, Springer, 2011.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @article{DF2011a,
  author = {Vincenzo De Florio},
  title = {Software Assumptions Failure Tolerance: Role, Strategies, and Visions},
  journal = {Chapter in Architecting Dependable Systems, Vol. 7, (Antonio Casimiro, Rogério de Lemos, and Cristina Gacek, Eds.), Lecture Notes in Computer Science},
  volume = {6420},
  year = {2011},
  publisher={Springer},
  url = {content/publications/2011/ads7_deflorio.pdf},
  abstract = {At our behest or otherwise, while our software is being
  executed, a huge variety of design assumptions is
  continuously matched with the truth of the current condition. While
  standards and tools exist to express and verify some of these
  assumptions, in practice most of them end up being either sifted off or
  hidden between the lines of our codes. Across the system layers, a
  complex and at times obscure web of assumptions determines the
  quality of the match of our software with its deployment platforms and
  run-time environments. Our position is that it becomes increasingly
  important being able to design software systems with architectural and
  structuring techniques that allow software to be decomposed to reduce its complexity,
  but without hiding in the process vital hypotheses and assumptions.
  In this paper we discuss this problem, introduce
  three potentially dangerous consequences of its denial,
  and propose three strategies to facilitate their treatment.
  Finally we propose our vision towards a new holistic approach
  to software development to overcome the shortcomings offered
  by fragmented views to the problem of assumption failures.}
  }
  
  Abstract:
  At our behest or otherwise, while our software is being a huge variety of design assumptions is matched with the truth of the current condition. While and tools exist to express and verify some of these in practice most of them end up being either sifted off or between the lines of our codes. Across the system layers, a and at times obscure web of assumptions determines the of the match of our software with its deployment platforms and environments. Our position is that it becomes increasingly being able to design software systems with architectural and techniques that allow software to be decomposed to reduce its complexity, without hiding in the process vital hypotheses and assumptions. this paper we discuss this problem, introduce potentially dangerous consequences of its denial, propose three strategies to facilitate their treatment. we propose our vision towards a new holistic approach software development to overcome the shortcomings offered fragmented views to the problem of assumption failures.

2010

• Interference Cancellation Tree Algorithms with k-Signal Memory Locations
  G. T. Peeters & B. Van Houdt
  IEEE Transactions on Communications, Vol. 58, No. 11, pp. 3056-3061, 2010.
  BibTeX | PDF Available
  
  Bibtex:
  @article{gpeeters2010,
  author = {G. T. Peeters and B. Van Houdt},
  title = {Interference Cancellation Tree Algorithms with k-Signal Memory Locations},
  journal = {IEEE Transactions on Communications},
  year = {2010},
  volume = {58},
  number = {11},
  month = nov,
  pages = {3056-3061},
  URL = {content/publications/2009/kmemory.pdf}
  }
  
  Abstract:
  Not available

• An Architecture-based Adaptation for Soft Real-time Applications
  Ning Gui, Hong Sun & Chris Blondia
  International Journal of Adaptive, Resilient and Autonomic Systems, Vol. 1, No. 4, 2010.
  BibTeX
  
  Bibtex:
  @Article{GSB10,
  author = {Ning Gui and Hong Sun and Chris Blondia},
  title = {An Architecture-based Adaptation
  Framework for Soft Real-time
  Applications},
  journal = {International Journal of Adaptive, Resilient and Autonomic Systems},
  volume = {1},
  number = {4},
  month = {December},
  year = {2010}
  }
  
  Abstract:
  Not available

• Delay and throughput analysis of tree algorithms for random access over noisy collision channels
  B. Van Houdt & R. Block
  Proceedings of NETCOOP 2010, Ghent, Belgium, pp. 25-32, 2010.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{dagstuhl,
  author = {B. Van Houdt and R. Block},
  title = {Delay and throughput analysis of tree algorithms for random access over noisy collision channels},
  booktitle = {Proceedings of NETCOOP 2010},
  pages = {25-32},
  year = {2010},
  month = {NOV},
  location = {Ghent, Belgium},
  URL = {content/publications/2010/NETCOOP2010_VanHoudt.pdf}
  }
  
  Abstract:
  Not available

• A Mean Field Model for an Optical Switch with a Large Number of Wavelengths and Centralized Partial Conversion
  J. F. Perez & B. Van Houdt
  Performance Evaluation, Vol. 67, No. 11, pp. 1044-1058, 2010.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{perez,
  author = {J. F. Perez and B. Van Houdt},
  title = {A Mean Field Model for an Optical Switch with a Large
  Number of Wavelengths and Centralized Partial Conversion},
  booktitle = {Performance Evaluation},
  volume = {67},
  number = {11},
  pages = {1044--1058},
  year = {2010},
  month = {NOV},
  URL = {content/publications/2010/PerezVanHoudt_Performance2010.pdf}
  }
  
  Abstract:
  Not available

• Cross-layer tuning of the neighbor sensing mechanism in mobile ad hoc networks
  N. Letor & C. Blondia
  Proc. Second IEEE International Workshop on Mobile Computing and Networking Technologies (WMCNT2010) in conjunction with ICUMT 2010, 2010.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @ARTICLE{nletor10a,
  author = {N. Letor, C. Blondia},
  title = {Cross-layer tuning of the neighbor sensing mechanism in mobile ad hoc networks},
  abstract = {The mobility of an ad hoc network can severely degrade the performance of the wireless network, as a direct consequence of frequently occurring link break events. An ad hoc routing protocol must react swiftly to these events by recomputing the forwarding table. Typical routing protocols rely on a timeout mechanism to notify a failing link. This causes a gap between the link failure and the detection of this event, resulting in packet loss for data streams passing over the failing link.
  In this paper we present a new cross-layer neighbor sensing mechanism for an ad hoc routing protocol in mobile ad hoc networks. By tuning the cross-layer transmission parameters of the neighbor sensing signaling packets, we divide the communi- cation range of the mobile node into two zones: a smaller virtual range for the ad hoc routing protocol and a larger effective communication range for data streams.
  When a neighboring node moves away, the larger range enables a mobile node to continue to receive data packets from that node, while the routing protocol is reacting to the virtual link break by recomputing the forwarding table. This enables the routing protocol to find an alternative route before the neighboring node moves out of the communication range.},
  booktitle = {Proc. Second IEEE International Workshop on Mobile Computing and Networking Technologies (WMCNT2010) in conjunction with ICUMT 2010},
  year = {2010},
  month = {October}
  URL = {}
  }
  
  Abstract:
  The mobility of an ad hoc network can severely degrade the performance of the wireless network, as a direct consequence of frequently occurring link break events. An ad hoc routing protocol must react swiftly to these events by recomputing the forwarding table. Typical routing protocols rely on a timeout mechanism to notify a failing link. This causes a gap between the link failure and the detection of this event, resulting in packet loss for data streams passing over the failing link. this paper we present a new cross-layer neighbor sensing mechanism for an ad hoc routing protocol in mobile ad hoc networks. By tuning the cross-layer transmission parameters of the neighbor sensing signaling packets, we divide the communi- cation range of the mobile node into two zones: a smaller virtual range for the ad hoc routing protocol and a larger effective communication range for data streams. When a neighboring node moves away, the larger range enables a mobile node to continue to receive data packets from that node, while the routing protocol is reacting to the virtual link break by recomputing the forwarding table. This enables the routing protocol to find an alternative route before the neighboring node moves out of the communication range.

• Analyzing M/G/1-type Markov chains with low-rank downward transitions
  J. F. Pérez & B. Van Houdt
  Proceedings of the 6th International Workshop on the Numerical Solution of Markov Chains (NSMC), Williamsburg, Virginia (USA), pp. 75-78, 2010.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{dagstuhl,
  author = {J. F. P{\'e}rez and B. Van Houdt},
  title = {Analyzing M/G/1-type Markov chains with low-rank downward transitions},
  booktitle = {Proceedings of the 6th International Workshop on the Numerical Solution of Markov Chains (NSMC)},
  pages = {75--78},
  year = {2010},
  month = {SEP},
  location = {Williamsburg, Virginia (USA)},
  URL = {content/publications/2010/Perez_VanHoudt_NSMC2010.pdf}
  }
  
  Abstract:
  Not available

• A phase-type representation for the queue length distribution of a semi-Markovian queue
  B. Van Houdt
  Proc of QEST 2010, Williamsburg, Virginia (USA), pp. 49-58, 2010.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{QEST2010,
  author = B. Van Houdt},
  title = {A phase-type representation for the queue length
  distribution of a semi-Markovian queue},
  booktitle = {Proc of QEST 2010},
  pages = {49--58},
  year = {2010},
  month = {SEP},
  location = {Williamsburg, Virginia (USA)},
  URL = {content/publications/2010/QEST2010_Vanhoudt.pdf}
  }
  
  Abstract:
  Not available

• Numerical Solution of Polling Systems for Analyzing Networks on Chips
  B. Van Houdt
  Proc of NSMC 2010, Williamsburg, Virginia (USA), pp. 90-93, 2010.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{dagstuhl,
  author = {B. Van Houdt},
  title = {Numerical Solution of Polling Systems for
  Analyzing Networks on Chips},
  booktitle = {Proc of NSMC 2010},
  pages = {90--93},
  year = {2010},
  month = {SEP},
  location = {Williamsburg, Virginia (USA)},
  URL = {content/publications/2010/NSMC2010_Vanhoudt.pdf}
  }
  
  Abstract:
  Not available

• Design and Analysis of Multi-carrier Multiple Access Systems without Feedback
  G.T. Peeters & B. Van Houdt
  Amsterdam, The Netherlands, Proc of ITC-22, 2010.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{ITC22,
  author = {G.T. Peeters and B. Van Houdt},
  title = {Design and Analysis of Multi-carrier Multiple Access Systems without Feedback},
  series = {Proc of ITC-22},
  year = {2010},
  month = {September},
  location = {Amsterdam, The Netherlands},
  URL = {content/publications/2010/ITC22_PeetersVanHoudt.pdf}
  }
  
  Abstract:
  Not available

• Service-oriented Communities: Visions and Contributions towards Social Organizations
  Vincenzo De Florio & Chris Blondia
  Proceedings of the Fifth International Workshop on MObile and NEtworking Technologies for social applications (MONET 2010), Lecture Notes in Computer Science vol.6428, 2010.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{DFB10c,
  author = {Vincenzo De Florio and Chris Blondia},
  title = {Service-oriented Communities: Visions and Contributions towards Social Organizations},
  booktitle = {Proceedings of the Fifth International Workshop on MObile and NEtworking Technologies for social applications (MONET 2010), Lecture Notes in Computer Science vol.6428},
  address = {Crete, Greece},
  tages = {319--328},
  month = {October},
  url = {content/publications/2010/cr.pdf},
  year = {2010},
  abstract = {With the increase of the populations, resources are becoming scarcer, and a smarter way to make use of them becomes a vital necessity of our societies. On the other hand, resource management is traditionally carried out through well established organizations, policies, and regulations that are often considered as impossible to restructure. Our position is that merely expanding the traditional approaches might not be enough. Systems must be radically rethought in order to achieve a truly effective and rational use of the available resources. Classical concepts such as demand and supply need to be rethought as well, as they operate artificial classifications that limit the true potential of systems and organizations. Here we propose our vision to future, 'smarter' systems able to overcome the limitations of the status quo. An example of such systems is the social organization that we call Service-oriented Community, which we briefly describe. We believe that such organizations---in heterarchical coexistence with traditional systems---provide the features necessary to prevent societal lock-ins like the ones we are experiencing in assisting our elderly ones.},
  }
  
  Abstract:
  With the increase of the populations, resources are becoming scarcer, and a smarter way to make use of them becomes a vital necessity of our societies. On the other hand, resource management is traditionally carried out through well established organizations, policies, and regulations that are often considered as impossible to restructure. Our position is that merely expanding the traditional approaches might not be enough. Systems must be radically rethought in order to achieve a truly effective and rational use of the available resources. Classical concepts such as demand and supply need to be rethought as well, as they operate artificial classifications that limit the true potential of systems and organizations. Here we propose our vision to future, smarter systems able to overcome the limitations of the status quo. An example of such systems is the social organization that we call Service-oriented Community, which we briefly describe. We believe that such organizations---in heterarchical coexistence with traditional systems---provide the features necessary to prevent societal lock-ins like the ones we are experiencing in assisting our elderly ones.,

• Wireless Sensor Network Interconnection Protocol
  Kurt Smolderen, Peter De Cleyn & Chris Blondia
  IEEE Globecom 2010 Workshop on Heterogeneous, Multi-hop Wireless and Mobile Networks (HeterWMN 2010), 2010.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{Anon1012:Wireless,
  AUTHOR = {Kurt Smolderen and Peter De Cleyn and Chris Blondia},
  TITLE = {Wireless Sensor Network Interconnection Protocol},
  BOOKTITLE = {IEEE Globecom 2010 Workshop on Heterogeneous, Multi-hop Wireless and Mobile Networks (HeterWMN 2010)},
  ADDRESS = {Miami, Florida, USA},
  DAYS = 6,
  MONTH = 12,
  YEAR = 2010,
  KEYWORDS = {gateway design, integration, internet protocol, protocol architecture, wireless sensor networks},
  ABSTRACT = {Wireless Sensor Networks (WSNs) are at high speed gaining in popularity. Because of this increased adoption, the need for integration with existing technologies becomes more prominent. In practice, a WSN is often deployed in environments were both wired and wireless data networks are also present. Consider for instance a WSN which acts as a climate monitoring or fire detection system in a large office building. As WSNs are typically networks with high constraints regarding resource efficiency, it would be beneficial if they could use the available data networks as additional transport medium for its internal data. In this paper we describe an interconnection protocol and associated sensor gateway design which enables the transparent use of both wired and wireless data networks by WSNs. Through this setup, the WSN will detect the non-sensor devices as virtual sensor nodes and consider them when determining the optimal routing paths.}
  URL = {content/publications/2010/HeterWMN2010_Smolderen_DeCleyn.pdf}
  }
  
  Abstract:
  Wireless Sensor Networks (WSNs) are at high speed gaining in popularity. Because of this increased adoption, the need for integration with existing technologies becomes more prominent. In practice, a WSN is often deployed in environments were both wired and wireless data networks are also present. Consider for instance a WSN which acts as a climate monitoring or fire detection system in a large office building. As WSNs are typically networks with high constraints regarding resource efficiency, it would be beneficial if they could use the available data networks as additional transport medium for its internal data. In this paper we describe an interconnection protocol and associated sensor gateway design which enables the transparent use of both wired and wireless data networks by WSNs. Through this setup, the WSN will detect the non-sensor devices as virtual sensor nodes and consider them when determining the optimal routing paths.

• On the link between Markovian trees and tree-structured Markov chains
  S. Hautphenne & B. Van Houdt
  European Journal of Operations Research, Vol. 201, No. 3, pp. 791-798, 2010.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{total,
  author = {S. Hautphenne and B. Van Houdt},
  title = {On the link between Markovian trees and tree-structured Markov chains},
  booktitle = {European Journal of Operations Research},
  volume = {201},
  number = {3},
  pages = {791--798},
  year = {2010},
  URL = {content/publications/2009/EJOR2010final.pdf}
  }
  
  Abstract:
  Not available

• On the Dual Relationship between Markov Chains of GI/M/1 and M/G/1 type
  P. G. Taylor & B. Van Houdt
  Stochastic Models, Vol. 42, No. 1, pp. 210-225, 2010.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{total,
  author = {P. G. Taylor and B. Van Houdt},
  title = {On the Dual Relationship between Markov Chains of GI/M/1 and M/G/1 type},
  booktitle = {Stochastic Models},
  volume = {42},
  number = {1},
  pages = {210--225},
  year = {2010},
  URL = {content/publications/2010/TaylorVanHoudtRevision.pdf}
  }
  
  Abstract:
  Not available

• Sensitivity Analysis of the Optimal Parameter Settings of an LTE Packet Scheduler
  I.F. Diaz, R. Litjens, H. van den Berg, D. Dimitrova & K. Spaey
  Proceedings of VTC2010-Spring, Taipei, Taiwan, 2010.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{VTCSpring2010,
  author = {I.F. Diaz, R. Litjens, H. van den Berg, D. Dimitrova and K. Spaey},
  title = {Sensitivity Analysis of the Optimal Parameter Settings of an LTE Packet Scheduler},
  booktitle = {Proceedings of VTC2010-Spring},
  year = {2010},
  month = may,
  location = {Taipei, Taiwan},
  URL = {content/publications/2010/SOCRATES_2010_VTCSpring PS.pdf}
  }
  
  Abstract:
  Not available

• Markovian approximations for a grid computing network with a ring structure
  J. F. Pérez & B. Van Houdt
  Stochastic Models, Vol. 26, No. 3, pp. 357-383, 2010.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @ARTICLE{perevanh10ring,
  author = {J. F. P{\'e}rez and B. {Van Houdt}},
  title = {Markovian approximations for a grid computing network with a ring structure},
  booktitle = {Stochastic Models},
  volume = {26},
  number = {3},
  pages = {357--383},
  year = {2010},
  month = {JUL},
  URL = {content/publications/2010/perevanh10ring.pdf},
  abstract = {Optical grid networks allow many computing sites to share their resources by connecting them through high-speed links, providing a more efficient use of the resources and a timely response for incoming jobs. These jobs originate from users connected to each of the sites and, in contrast to traditional queueing networks, a particular job does not have to be processed in a predefined site. Furthermore, a job is always processed locally if there is an available local server. In this paper we propose two different methods to approximate the performance of an optical grid network with a ring topology. The first method is based on approximating the inter-overflow time process, while the second separately characterizes the periods where jobs are overflowed and the periods where they are served locally. Both approaches rely on a marked Markovian representation of the overflow process at each station and on reducing this representation by moment-matching methods. The results show that the methods accurately approximate the rate of locally processed jobs, one of the main performance measures.}
  }
  
  Abstract:
  Optical grid networks allow many computing sites to share their resources by connecting them through high-speed links, providing a more efficient use of the resources and a timely response for incoming jobs. These jobs originate from users connected to each of the sites and, in contrast to traditional queueing networks, a particular job does not have to be processed in a predefined site. Furthermore, a job is always processed locally if there is an available local server. In this paper we propose two different methods to approximate the performance of an optical grid network with a ring topology. The first method is based on approximating the inter-overflow time process, while the second separately characterizes the periods where jobs are overflowed and the periods where they are served locally. Both approaches rely on a marked Markovian representation of the overflow process at each station and on reducing this representation by moment-matching methods. The results show that the methods accurately approximate the rate of locally processed jobs, one of the main performance measures.

• A Comprehensive Survey of Wireless Body Area Networks: On PHY, MAC, and Network Layers solutions
  Sana Ullah, Henry Higgins, Bart Braem, Benoit Latre, Chris Blondia, Ingrid Moerman, Shahnaz Saleem & Kyung Sup Kwak
  Journal of Medical Systems, pp. 1-30, Springer Netherlands, 2010.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @article{bbraem10comprehensivewbansurvey,
  author = {Sana Ullah and Henry Higgins and Bart Braem and Benoit Latre and Chris Blondia and Ingrid Moerman and Shahnaz Saleem and Kyung Sup Kwak},
  title = {A Comprehensive Survey of Wireless Body Area Networks: On PHY, MAC, and Network Layers solutions},
  journal = {Journal of Medical Systems},
  publisher = {Springer Netherlands},
  issn = {0148-5598},
  pages = {1-30},
  url = {content/publications/2010/bbraem10wbansurvey.pdf},
  year = {2010},
  abstract = {Recent advances in microelectronics and integrated circuits, system-on-chip design, wireless com- munication and intelligent low-power sensors have allowed the realization of a Wireless Body Area Network (WBAN). A WBAN is a collection of low-power, miniaturized, invasive/non-invasive lightweight wireless sensor nodes that monitor the human body functions and the surrounding environment. In addition, it supports a number of innovative and interesting applications that include ubiquitous healthcare, entertainment, interactive gaming, and military applications. In this paper, the fundamental mechanisms of WBAN including architecture and topology, wireless implant communication, low-power Medium Access Control (MAC) and routing protocols are reviewed. A comprehensive study of proposed technologies for WBAN at physical (PHY), MAC, and Network layers is presented and many useful solutions are discussed for each layer. Finally, numerous WBAN applications are highlighted.}
  }
  
  Abstract:
  Recent advances in microelectronics and integrated circuits, system-on-chip design, wireless com- munication and intelligent low-power sensors have allowed the realization of a Wireless Body Area Network (WBAN). A WBAN is a collection of low-power, miniaturized, invasive/non-invasive lightweight wireless sensor nodes that monitor the human body functions and the surrounding environment. In addition, it supports a number of innovative and interesting applications that include ubiquitous healthcare, entertainment, interactive gaming, and military applications. In this paper, the fundamental mechanisms of WBAN including architecture and topology, wireless implant communication, low-power Medium Access Control (MAC) and routing protocols are reviewed. A comprehensive study of proposed technologies for WBAN at physical (PHY), MAC, and Network layers is presented and many useful solutions are discussed for each layer. Finally, numerous WBAN applications are highlighted.

• Binary TDMA Schedule by Means of Egyptian Fractions for Real-time WSNs on TMotes
  Wim Torfs & Chris Blondia
  Proceedings of Med-Hoc-Net 2010, Juan-les-Pins, France, 2010.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{
  author = {Wim Torfs and Chris Blondia},
  title = {Binary TDMA Schedule by Means of Egyptian Fractions for Real-time WSNs on TMotes},
  booktitle = {Proceedings of Med-Hoc-Net 2010},
  year = {2010},
  month = {JUN},
  location = {Juan-les-Pins, France},
  url = {content/publications/2010/wtorfs_medhocnet_2010.pdf},
  abstract = {In Wireless Sensor Networks (WSNs), the user
  should not be bothered with configuring the network, depending
  on the kind of sensors that he/she is using. It should only be a
  matter of deploying the sensors and they should do the necessary
  effort to construct a network. Since most of these networks use
  low power devices, the energy consumption is vital. The most
  suited medium access method in order to waste as few energy as
  possible, is Time Division Multiple Access (TDMA). TDMA has
  however the reputation of being a rigid access method. In this
  paper, we present a TDMA access method for passive sensors,
  i.e. sensors are constant bitrate sources. The presented protocol
  does not only take into account the energy, but it also ensures
  that every sensor gets its data on time at the sink and this
  in a fair fashion. Even more, the latency of the transmission
  is deterministic. We could say that real-time communication is
  possible. The protocol is developed keeping in mind the practical
  limitations of actual hardware by limiting the memory usage
  and the communication overhead. The schedule that determines
  which sensor can send when, which can be encoded in a very
  small footprint, and needs to be sent only once. To prove our
  statement, we implemented our scheduling protocol on TMotes.}
  }
  
  Abstract:
  In Wireless Sensor Networks (WSNs), the user not be bothered with configuring the network, depending the kind of sensors that he/she is using. It should only be a of deploying the sensors and they should do the necessary to construct a network. Since most of these networks use power devices, the energy consumption is vital. The most medium access method in order to waste as few energy as is Time Division Multiple Access (TDMA). TDMA has the reputation of being a rigid access method. In this we present a TDMA access method for passive sensors, sensors are constant bitrate sources. The presented protocol not only take into account the energy, but it also ensures every sensor gets its data on time at the sink and this a fair fashion. Even more, the latency of the transmission deterministic. We could say that real-time communication is The protocol is developed keeping in mind the practical of actual hardware by limiting the memory usage the communication overhead. The schedule that determines sensor can send when, which can be encoded in a very footprint, and needs to be sent only once. To prove our we implemented our scheduling protocol on TMotes.

• Node Mobility Support in Body Sensor Networks
  Bart Braem, Peter De Cleyn & Chris Blondia
  ICST BodyNets2010: 5th International ICST Conference on Body Area Networks, Corfu, Greece, ACM, 2010.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{bbraem10bodynets,
  author = {Bart Braem and Peter De Cleyn and Chris Blondia},
  title = {Node Mobility Support in Body Sensor Networks},
  booktitle = {ICST BodyNets2010: 5th International ICST Conference on Body Area Networks},
  year = {2010},
  publisher={ACM},
  month = {September},
  location = {Corfu, Greece},
  abstract = {Body Sensor Networks (BSNs) form a promising technology to supply healthcare to an ageing population. Current solutions all assume single-hop networks, while research indicates the need for support of multi-hop topologies. A small movement in a network with small radio ranges, causes frequent node mobility. This work presents the first three algorithms to support Mobile BSNs. It is shown that the algorithms support mobility while being energy efficient.},
  url = {content/publications/2010/bbraem10bsn.pdf}
  }
  
  Abstract:
  Body Sensor Networks (BSNs) form a promising technology to supply healthcare to an ageing population. Current solutions all assume single-hop networks, while research indicates the need for support of multi-hop topologies. A small movement in a network with small radio ranges, causes frequent node mobility. This work presents the first three algorithms to support Mobile BSNs. It is shown that the algorithms support mobility while being energy efficient.

• Run-time Reconfiguration Software Platform for Autonomous Robots
  Ning Gui, Pieter-Jan Pintens, Vincenzo De Florio & Chris Blondia
  Proceedings of the 4th International workshop on and DependAble Mobile Ubiquitous (ADAMUS 2010), held in the framework of 7th ACM International Conference on Pervasive Services (ACM ICPS 2010), Berlin, Germany, 2010.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{GuiDF10a,
  author = {Ning Gui and Pieter-Jan Pintens
  and Vincenzo De Florio and Chris Blondia},
  title = {Run-time Reconfiguration Software Platform for
  Autonomous Robots},
  booktitle = {Proceedings of the 4th International workshop on
  Adaptive and DependAble Mobile Ubiquitous
  Systems (ADAMUS 2010), held in the framework of
  the 7th ACM International Conference on
  Pervasive Services (ACM ICPS 2010)},
  year = {2010},
  month = {July},
  day = {13--15},
  location = {Berlin, Germany},
  abstract = {},
  URL = {content/publications/2011/ijaras11ning.pdf}
  }
  
  Abstract:
  

• Interference Cancellation Tree Algorithms with k-Signal Memory Locations
  Gino T. Peeters & Benny Van Houdt
  Accepted for publication in IEEE Transactions on Communications, 2010.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @article{gpeeters2010tcom,
  author = {Gino T. Peeters and Benny Van Houdt},
  title = {Interference Cancellation Tree Algorithms with k-Signal Memory Locations,
  journal = {Accepted for publication in IEEE Transactions on Communications },
  year = {2010},
  abstract = {Recently, tree algorithms have been combined with successive interference cancellation to achieve a substantially higher maximum stable throughput (MST). All previous work assumed either a single or an unbounded number of signal memory locations, with MSTs of 0.662 and 0.693, respectively. In this paper, we address the gap between these two algorithms by designing and analyzing two novel general k-signal memory location algorithms.},
  url={content/publications/2010/peeters_tcom2010.pdf}
  }
  
  Abstract:
  Recently, tree algorithms have been combined with successive interference cancellation to achieve a substantially higher maximum stable throughput (MST). All previous work assumed either a single or an unbounded number of signal memory locations, with MSTs of 0.662 and 0.693, respectively. In this paper, we address the gap between these two algorithms by designing and analyzing two novel general k-signal memory location algorithms.

• Mean Field Calculation for Optical Grid Dimensioning
  B. Van Houdt, C. Develder, J. F. Pérez, M. Pickavet & B. Dhoedt
  IEEE/OSA Journal of Optical Communications and Networking, Vol. 2, No. 6, pp. 355-367, 2010.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @ARTICLE{vanh10gridmeanfield,
  author = {B. {Van Houdt} and C. Develder and J. F. P{\'e}rez and M. Pickavet and B. Dhoedt},
  title = {Mean Field Calculation for Optical Grid Dimensioning},
  booktitle = {IEEE/OSA Journal of Optical Communications and Networking},
  volume = {2},
  number = {6},
  pages = {355--367},
  year = {2010},
  month = {JUN},
  URL = {content/publications/2010/vanh10gridmeanfield.pdf},
  abstract = {For traditional optical network dimensioning, a plethora of algorithms exists to design the amount of network resources required to accommodate a given amount of traffic, expressed as a (source,destination)-based traffic matrix. In optical Grid dimensioning however, the anycast principle applies: Grid users do not really care where exactly their tasks (Grid jobs) end up being executed. Thus,
  the destination of traffic is not known beforehand and traditional dimensioning algorithms are not applicable. In this paper we propose a mean field calculation method to analytically derive the traffic matrix for given job arrival intensities at the originating Grid sites (the sources). We also indicate how it can be integrated in a step-wise dimensioning approach to compute not only the amount of network resources, but also Grid resources (computational and/or storage). Hence it forms part of a solution for Grid dimensioning: determining how many servers to provide, where to place them, and which network to install for interconnecting server sites and users generating Grid jobs.}
  }
  
  Abstract:
  For traditional optical network dimensioning, a plethora of algorithms exists to design the amount of network resources required to accommodate a given amount of traffic, expressed as a (source,destination)-based traffic matrix. In optical Grid dimensioning however, the anycast principle applies: Grid users do not really care where exactly their tasks (Grid jobs) end up being executed. Thus, destination of traffic is not known beforehand and traditional dimensioning algorithms are not applicable. In this paper we propose a mean field calculation method to analytically derive the traffic matrix for given job arrival intensities at the originating Grid sites (the sources). We also indicate how it can be integrated in a step-wise dimensioning approach to compute not only the amount of network resources, but also Grid resources (computational and/or storage). Hence it forms part of a solution for Grid dimensioning: determining how many servers to provide, where to place them, and which network to install for interconnecting server sites and users generating Grid jobs.

• Supporting Mobility in Body Sensor Networks
  Bart Braem, Peter De Cleyn & Chris Blondia
  BSN2010: Wearable and Implantable Body Sensor Networks, International Workshop on, Singapore, Singapore, pp. 52-55, IEEE Computer Society, 2010.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{bbraem10bsn,
  author = {Bart Braem and Peter De Cleyn and Chris Blondia},
  title = {Supporting Mobility in Body Sensor Networks},
  isbn = {978-0-7695-4065-8},
  year = {2010},
  pages = {52-55},
  doi = {http://doi.ieeecomputersociety.org/10.1109/BSN.2010.16},
  publisher = {IEEE Computer Society},
  address = {Los Alamitos, CA, USA},
  booktitle = {BSN2010: Wearable and Implantable Body Sensor Networks, International Workshop on},
  month = {June},
  location = {Singapore, Singapore},
  URL = {content/publications/2010/bbraem10bsn.pdf},
  abstract = {Body Sensor Networks (BSNs) form a promising technology to supply healthcare to an ageing population. A large number of sensor devices, radios and MAC protocols are being developed. However, because of the small scale of a BSN, node mobility will arise frequently. This work presents the first algorithm to support such Mobile BSNs, while remaining energy efficient.}
  }
  
  Abstract:
  Body Sensor Networks (BSNs) form a promising technology to supply healthcare to an ageing population. A large number of sensor devices, radios and MAC protocols are being developed. However, because of the small scale of a BSN, node mobility will arise frequently. This work presents the first algorithm to support such Mobile BSNs, while remaining energy efficient.

• A Survey on Wireless Body Area Networks
  Benoît Latré, Bart Braem, Chris Blondia, Ingrid Moerman & Piet Demeester
  Wireless Networks, pp. 1-18, Springer Netherlands, 2010.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @article{bbraem10wbansurvey,
  author = {Beno{\^i}t Latr{\'e} and Bart Braem and Chris Blondia and Ingrid Moerman and Piet Demeester},
  title = {A Survey on Wireless Body Area Networks},
  journal = {Wireless Networks},
  publisher = {Springer Netherlands},
  year = {2010},
  pages = {1-18},
  url = {content/publications/2010/bbraem10wbansurvey.pdf},
  abstract = {The increasing use of wireless networks and the constant miniaturization of electrical devices has empowered the development of Wireless Body Area Networks (WBANs). In these networks various sensors are attached on clothing or on the body or even implanted under the skin. The wireless nature of the network and the wide variety of sensors offer numerous new, practical and innovative applications to improve health care and the Quality of Life. The sensors of a WBAN measure for example the heartbeat, the body temperature or record a prolonged electrocardiogram. Using a WBAN, the patient experiences a greater physical mobility and is no longer compelled to stay in the hospital. This paper offers a survey of the concept of Wireless Body Area Networks. First, we focus on some applications with special interest in patient monitoring. Then the communication in a WBAN and its positioning between the different technologies is discussed. An overview of the current research on the physical layer, existing MAC and network protocols is given. Further, cross layer and quality of service is discussed. As WBANs are placed
  on the human body and often transport private data, security is also considered. An overview of current and past projects is given. Finally, the open research issues and challenges are pointed out.
  }
  }
  
  Abstract:
  The increasing use of wireless networks and the constant miniaturization of electrical devices has empowered the development of Wireless Body Area Networks (WBANs). In these networks various sensors are attached on clothing or on the body or even implanted under the skin. The wireless nature of the network and the wide variety of sensors offer numerous new, practical and innovative applications to improve health care and the Quality of Life. The sensors of a WBAN measure for example the heartbeat, the body temperature or record a prolonged electrocardiogram. Using a WBAN, the patient experiences a greater physical mobility and is no longer compelled to stay in the hospital. This paper offers a survey of the concept of Wireless Body Area Networks. First, we focus on some applications with special interest in patient monitoring. Then the communication in a WBAN and its positioning between the different technologies is discussed. An overview of the current research on the physical layer, existing MAC and network protocols is given. Further, cross layer and quality of service is discussed. As WBANs are placed the human body and often transport private data, security is also considered. An overview of current and past projects is given. Finally, the open research issues and challenges are pointed out.

• The ADAMO Project: Architecture to Support Communication for Emergency Services
  J. Bergs, D. Naudts, N. Van den Wijngaert, C. Blondia, I. Moerman, P. Demeester, J. Paquay, F. De Reymaeker & J. Baekelmans
  Proceedings of the Eighth Annual IEEE International Conference on Pervasive Computing and Communications Workshops (PerCom Workshops), Mannheim, Germany, 2010.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{pernem,
  author = {J. Bergs and D. Naudts and N. Van den Wijngaert and C. Blondia and I. Moerman and P. Demeester and J. Paquay and F. De Reymaeker and J. Baekelmans},
  title = {The ADAMO Project: Architecture to Support Communication for Emergency Services},
  booktitle = {Proceedings of the Eighth Annual IEEE International Conference on Pervasive Computing and Communications Workshops (PerCom Workshops)},
  year = {2010},
  month = {MAR},
  location = {Mannheim, Germany},
  URL = {content/publications/2010/johanbergs10PerNEM.pdf},
  abstract = { When emergency services are in a crisis situation, their greatest need is to have good communication. Every person involved needs to have the most up-to-date and relevant information at all times and needs to be able to communicate with his colleagues effectively. In order to support this, it is of great importance that the network used by the emergency services supports all necessary communication flows to make this communication as fluently as possible. In this paper, we will describe the architecture we developed in the IBBT project ADAMO - Advanced Disaster Architecture with Mobility Optimizations. }
  }
  
  Abstract:
  When emergency services are in a crisis situation, their greatest need is to have good communication. Every person involved needs to have the most up-to-date and relevant information at all times and needs to be able to communicate with his colleagues effectively. In order to support this, it is of great importance that the network used by the emergency services supports all necessary communication flows to make this communication as fluently as possible. In this paper, we will describe the architecture we developed in the IBBT project ADAMO - Advanced Disaster Architecture with Mobility Optimizations.

• Impact of cross-layer adaptations of Mobile IP on IEEE 802.11 networks on video streaming.
  Peter De Cleyn & Chris Blondia
  Accepted for publication in the International Journal of Adaptive, Resilient and Autonomic Systems, IGI Publishing, 2010.
  BibTeX
  
  Bibtex:
  @Article{pdecleyniaras10,
  author = {Peter De Cleyn and Chris Blondia},
  title = {{Impact of cross-layer adaptations of Mobile IP on IEEE 802.11 networks on video streaming.}},
  journal = { Accepted for publication in the International Journal of Adaptive, Resilient and Autonomic Systems},
  year = {2010}
  publisher = {IGI Publishing}
  }
  
  Abstract:
  Not available

• Optimization of WS-BPEL Workflows through Business Process Re-engineering Patterns
  Jonas Buys, Vincenzo De Florio & Chris Blondia
  International Journal of Adaptive, Resilient and Autonomic Systems, Vol. 1, No. 3, pp. 25-41, 2010.
  BibTeX | PDF Available
  
  Bibtex:
  @Article{BDB10,
  author = {Jonas Buys and Vincenzo {De Florio} and Chris Blondia},
  title = {Optimization of WS-BPEL Workflows through Business Process Re-engineering
  Patterns},
  journal = {International Journal of Adaptive, Resilient and Autonomic Systems},
  year = {2010},
  volume = {1},
  pages = {25--41},
  number = {3},
  month = {July-September},
  url = {content/publications/2010/Buys2010.pdf}
  }
  
  Abstract:
  Not available

• Cost-effective software reliability through autonomic tuning of system resources
  Vincenzo De Florio & Chris Blondia
  invited presentation at the 2010 International Applied Reliability Symposium in Europe, Berlin, Germany, 2010.
  BibTeX
  
  Bibtex:
  @Misc{De10ARS,
  author = {Vincenzo De Florio and Chris Blondia},
  title = {Cost-effective software reliability through autonomic tuning of system resources},
  booktitle = {invited presentation at the 2010 International Applied Reliability Symposium in Europe},
  location = {Berlin, Germany},
  year = {2010},
  month = {April},
  day = {7--9},
  }
  
  Abstract:
  Not available

• Building Mutual Assistance Living Community for Elderly People
  Hong Sun, Vincenzo De Florio, Ning Gui & Chris Blondia
  in Jeffrey Soar, Ed., Intelligent Technologies for the Aged: The Grey Digital Divide, 2010.
  BibTeX | PDF Available
  
  Bibtex:
  @Article{SDGB10,
  author = {Hong Sun and Vincenzo De Florio and Ning Gui and Chris Blondia},
  title = {Building Mutual Assistance Living Community for Elderly People},
  journal = {in Jeffrey Soar, Ed., Intelligent Technologies for the Aged: The Grey Digital Divide},
  year = {2010},
  url = {content/publications/2010/bamac10.pdf}
  }
  
  Abstract:
  Not available

• Design Tool To Express Failure Detection Protocols
  Vincenzo De Florio & Chris Blondia
  accepted for publication in IET Software, 2010.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @Article{DeFBl10b,
  author = {Vincenzo De Florio and Chris Blondia},
  title = {Design Tool To Express Failure Detection Protocols},
  journal = {accepted for publication in IET Software},
  year = {2010},
  abstract = {Failure detection protocols---a fundamental building block for crafting
  fault-tolerant distributed systems---are in many cases
  described by their authors making use
  of informal pseudo-codes of their conception. Often these pseudo-codes
  use syntactical constructs that are not available in
  COTS programming languages such as C or C++. This translates into
  informal descriptions that call for ad hoc interpretations and implementations.
  Being informal, these descriptions cannot be tested by their authors, which
  may translate into insufficiently detailed or even faulty specifications.
  This paper tackles this problem introducing a formal syntax
  for those constructs and a C library that implements them---a tool-set
  to express and reason about failure detection protocols.
  The resulting specifications are longer but non ambiguous, and
  eligible for becoming a standard form.},
  url = {content/publications/2010/IET_Software.pdf},
  }
  
  Abstract:
  Failure detection protocols---a fundamental building block for crafting distributed systems---are in many cases by their authors making use informal pseudo-codes of their conception. Often these pseudo-codes syntactical constructs that are not available in programming languages such as C or C++. This translates into descriptions that call for ad hoc interpretations and implementations. informal, these descriptions cannot be tested by their authors, which translate into insufficiently detailed or even faulty specifications. paper tackles this problem introducing a formal syntax those constructs and a C library that implements them---a tool-set express and reason about failure detection protocols. resulting specifications are longer but non ambiguous, and eligible for becoming a standard form.

• TinySPOTComm: Facilitating Communication over IEEE 802.15.4 between Sun SPOTs and TinyOS-Based Motes
  Daniel van den Akker, Kurt Smolderen, Peter De Cleyn, Bart Braem & Chris Blondia
  Sensor Applications, Experimentation, and Logistics, Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, Vol. 29, pp. 177-194, Springer Berlin Heidelberg, 2010.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @inproceedings{vdAkker2010,
  title = {{TinySPOTComm}: Facilitating Communication over {IEEE} 802.15.4 between Sun {SPOTs} and {TinyOS-Based} Motes},
  author = {Daniel van den Akker and Kurt Smolderen and Peter De Cleyn and Bart Braem and Chris Blondia},
  booktitle = {Sensor Applications, Experimentation, and Logistics},
  publisher = {Springer Berlin Heidelberg},
  issn = {1867-8211 (Print) 1867-822X (Online)},
  isbn = {978-3-642-11869-2 (Print) 978-3-642-11870-8 (Online)},
  url = {content/publications/2009/dvdakker09tinyspotcomm.pdf},
  abstract = {The increasing popularity of sensor network has spawned a wide range of platforms and frameworks for sensor network development. While in theory nodes based on different frameworks should provide radio stack compatibility, in practice this is rarely the case. We explore this problem by providing a case study and introduce TinySPOTComm, a customized radio stack for the Sun SPOT platform which allows for radio communication between IEEE 802.15.4 based TinyOS motes and Sun SPOTs. The TinySPOTComm radio stack remains fully compatible with the Sun SPOT radio stack and its network performance is only marginally affected in comparison to the default Sun SPOT radio stack. Performance tests have shown good results when communicating between TinyOS motes and Sun SPOTs. The round trip time, when measured between a Sun SPOT and a TinyOS mote, is affected by no more than 15%, in comparison to the RTT between two TinyOS motes. In the same scenario an increase in throughput of more than 50% has been measured.},
  volume = {29},
  series = {Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering},
  year = {2010},
  keywords = {Sun SPOT - TinyOS - 802.15.4 - compatibility - sensor network},
  pages = {177--194},
  subject_collection = {Computer Science},
  doi = {10.1007/978-3-642-11870-8_12},
  }
  
  Abstract:
  The increasing popularity of sensor network has spawned a wide range of platforms and frameworks for sensor network development. While in theory nodes based on different frameworks should provide radio stack compatibility, in practice this is rarely the case. We explore this problem by providing a case study and introduce TinySPOTComm, a customized radio stack for the Sun SPOT platform which allows for radio communication between IEEE 802.15.4 based TinyOS motes and Sun SPOTs. The TinySPOTComm radio stack remains fully compatible with the Sun SPOT radio stack and its network performance is only marginally affected in comparison to the default Sun SPOT radio stack. Performance tests have shown good results when communicating between TinyOS motes and Sun SPOTs. The round trip time, when measured between a Sun SPOT and a TinyOS mote, is affected by no more than 15%, in comparison to the RTT between two TinyOS motes. In the same scenario an increase in throughput of more than 50% has been measured.

• Adaptation and dependability and their key role in modern software engineering
  Vincenzo De Florio & Chris Blondia
  International Journal of Adaptive, Resilient and Autonomic Systems, special ADAMUS issue, Vol. 1, No. 2, Marcello Cinque and Luca Foschini, Editors, 2010.
  BibTeX | PDF Available
  
  Bibtex:
  @Article{DeFBl10a,
  author = {Vincenzo De Florio and Chris Blondia},
  title = {Adaptation and dependability and their key role in modern software engineering},
  journal = {International Journal of Adaptive, Resilient and Autonomic Systems, special ADAMUS issue},
  editor = {Marcello Cinque and Luca Foschini, Editors},
  volume = {1},
  number = {2},
  month = {April},
  year = {2010},
  url = {content/publications/2010/ijaras1-2.pdf.pdf}
  }
  
  Abstract:
  Not available

• The Missing Ones: Key Ingredients Towards Effective Ambient Assisted Living Systems
  Hong Sun, Vincenzo De Florio, Ning Gui & Chris Blondia
  accepted for publication in the Journal of Ambient Intelligence and Smart Environments, 2010.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @Article{SDGB10b,
  author = {Hong Sun and Vincenzo De Florio and Ning Gui and Chris Blondia},
  title = {The Missing Ones: Key Ingredients Towards
  Effective Ambient Assisted Living Systems},
  journal = {accepted for publication in the Journal of Ambient Intelligence and Smart Environments},
  year = {2010},
  abstract={The population of elderly people keeps increasing rapidly, which becomes a predominant aspect of our societies. As
  such, solutions both efficacious and cost-effective need to be sought. Ambient Assisted Living (AAL) is a new approach which
  promises to address the needs from elderly people. In this paper, we claim that human participation is a key ingredient towards
  effective AAL systems, which not only saves social resources, but also has positive relapses on the psychological health of the
  elderly people. Challenges in increasing the human participation in ambient assisted living are discussed in this paper and solutions
  to meet those challenges are also proposed. We use our proposed mutual assistance community, which is built with service
  oriented approach, as an example to demonstrate how to integrate human tasks in AAL systems. Our preliminary simulation
  results are presented, which support the effectiveness of human participation.},
  url = {content/publications/2010/MissingOnes10.pdf}
  }
  
  Abstract:
  The population of elderly people keeps increasing rapidly, which becomes a predominant aspect of our societies. As solutions both efficacious and cost-effective need to be sought. Ambient Assisted Living (AAL) is a new approach which to address the needs from elderly people. In this paper, we claim that human participation is a key ingredient towards AAL systems, which not only saves social resources, but also has positive relapses on the psychological health of the people. Challenges in increasing the human participation in ambient assisted living are discussed in this paper and solutions meet those challenges are also proposed. We use our proposed mutual assistance community, which is built with service approach, as an example to demonstrate how to integrate human tasks in AAL systems. Our preliminary simulation results are presented, which support the effectiveness of human participation.

• A Secure Cross-layer Protocol for Multi-hop Wireless Body Area Networks
  Dave Singelée, Benoît Latré, Bart Braem, Michael Peeters, Marijke De Soete, Peter De Cleyn, Bart Preneel, Ingrid Moerman & Chris Blondia
  Ad-Hoc and Sensor Wireless Networks, Vol. 9, No. 1, pp. 53-72, Old City Publishing, 2010.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @ Article{bbraem08securewbanprotocol,
  author = {Dave Singel{\'e}e and Beno{\^i}t Latr{\'e} and Bart Braem and Michael Peeters and Marijke De Soete and Peter De Cleyn and Bart Preneel and Ingrid Moerman and Chris Blondia},
  title = {A Secure Cross-layer Protocol for Multi-hop Wireless Body Area Networks},
  journal = {Ad-Hoc and Sensor Wireless Networks},
  year = {2010},
  pages = {53-72},
  volume = {9},
  number ={1},
  publisher = {Old City Publishing},
  URL = {content/publications/2008/bbraem08securewbanprotocoljournal.pdf},
  abstract = {The development of Wireless Body Area Networks (WBANs) for
  wireless sensing and monitoring of a person's vital functions, is
  an enabler in providing better personal health care whilst
  enhancing the quality of life. A critical factor in the acceptance
  of WBANs is providing appropriate security and privacy protection
  of the wireless communication. This paper first describes a
  general health care platform and pinpoints the security challenges
  and requirements. Further it proposes and analyzes the CICADA-S
  protocol, a secure cross-layer protocol for WBANs. It is an
  extension of CICADA, which is a cross-layer protocol that handles
  both medium access and the routing of data in WBANs. The CICADA-S
  protocol is the first integrated solution that copes with threats
  that occur in this mobile medical monitoring scenario. It is shown
  that the integration of key management and secure, privacy
  preserving communication techniques within the CICADA-S protocol
  has low impact on the power consumption and throughput.},
  }
  
  Abstract:
  The development of Wireless Body Area Networks (WBANs) for sensing and monitoring of a person s vital functions, is enabler in providing better personal health care whilst the quality of life. A critical factor in the acceptance WBANs is providing appropriate security and privacy protection the wireless communication. This paper first describes a health care platform and pinpoints the security challenges requirements. Further it proposes and analyzes the CICADA-S a secure cross-layer protocol for WBANs. It is an of CICADA, which is a cross-layer protocol that handles medium access and the routing of data in WBANs. The CICADA-S is the first integrated solution that copes with threats occur in this mobile medical monitoring scenario. It is shown the integration of key management and secure, privacy communication techniques within the CICADA-S protocol has low impact on the power consumption and throughput.

2009

• Impact of introducing road charging on supporting mobile data networks
  W. Vandenberghe, J. Bergs, D. Carels, N. Van den Wijngaert, E. Van de Velde, C. Blondia, I. Moerman, P. Demeester & N. Dedene
  Proceedings of the Ninth International Conference on ITS Telecommunications, Lille, France, 2009.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{itst2009,
  author = {W. Vandenberghe, J. Bergs, D. Carels, N. Van den Wijngaert, E. Van de Velde, C. Blondia, I. Moerman, P. Demeester and N. Dedene},
  title = {Impact of introducing road charging on supporting mobile data networks},
  booktitle = {Proceedings of the Ninth International Conference on ITS Telecommunications},
  year = {2009},
  month = {OCT},
  location = {Lille, France},
  URL = {content/publications/2009/ITST2009.pdf},
  abstract = {}
  }
  
  Abstract:
  

• Models for capacity demand estimation in a TV broadcast network with variable bit rate TV channels
  Z. Avramova, D. De Vleeschauwer, K. Spaey, S. Wittevrongel, H. Bruneel & C. Blondia
  Revised Selected Papers of FITraMEn 2008, Lecture Notes in Computer Science, Vol. 5464, pp. 1-15, Springer, 2009.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{LNCS5464,
  author = {Z. Avramova and D. De Vleeschauwer and K. Spaey and S. Wittevrongel and H. Bruneel and C. Blondia},
  title = {Models for capacity demand estimation in a TV broadcast network with variable bit rate TV channels},
  booktitle = {Revised Selected Papers of FITraMEn 2008},
  volume = {5464},
  pages = {1--15},
  year = {2009},
  publisher = {Springer},
  series = {Lecture Notes in Computer Science},
  URL = {content/publications/2009/spaey_2009_LNCS5464.pdf}
  }
  
  Abstract:
  Not available

• Autoconfiguração de redes sem fio
  M. Amirijoo, R. Litjens, K. Spaey, M. Döttling, T. Jansen, N. Scully & U. Türke
  RTI (Redes, Telecom e Instalações) magazine, Vol. X, No. 111, pp. 58-63, 2009.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{RTI2009,
  author = {M. Amirijoo, R. Litjens, K. Spaey, M. D{\"o}ttling, T. Jansen, N. Scully and U. T{\"u}rke},
  title = {Autoconfigura{\cc}{\~a}o de redes sem fio},
  booktitle = {RTI (Redes, Telecom e Instala{\cc}{\~o}es) magazine},
  volume = {X},
  number = {111},
  pages = {58--63},
  year = {2009},
  month = {AUG},
  URL = {content/publications/2009/SOCRATES_2009_RTI.pdf}
  }
  
  Abstract:
  Not available

• System and Method for Adapting Software Architecture
  Ning Gui & Vincenzo De Florio
  request for grant of European patent EP09174712.1, 2009.
  BibTeX | PDF Available
  
  Bibtex:
  @Misc{DeGu09,
  author = {Ning Gui and Vincenzo De Florio},
  title = {System and Method for Adapting Software Architecture},
  booktitle = {request for grant of European patent EP09174712.1},
  year = {2009},
  month = {October},
  day = {30},
  url = {content/publications/2009/sysmeth.pdf}
  }
  
  Abstract:
  Not available

• Architecture and Scalable Testbed for Cooperative Systems in the NextGenITS Project
  D. Carels, W. Vandenberghe, J. Bergs, H. Capelle, E. Van de Velde, N. Van den Wijngaert, L. Van der Perre, I. Moerman, C. Blondia & P. Demeester
  Proc. The 16th World Congress and Exhibition on Intelligent Transport Systems and Services, Stockholm, Sweden, 2009.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{itsworld,
  author = { D. Carels and W. Vandenberghe and J. Bergs and H. Capelle and E. Van de Velde and N. Van den Wijngaert and L. Van der Perre and I. Moerman and C. Blondia and P. Demeester},
  title = {Architecture and Scalable Testbed for Cooperative Systems in the NextGenITS Project},
  booktitle = {Proc. The 16th World Congress and Exhibition on Intelligent Transport Systems and Services},
  year = {2009},
  month = {SEP},
  location = {Stockholm, Sweden},
  URL = {content/publications/2009/johanbergs09ITSWorld.pdf},
  abstract = { In the past research has been done on cooperative systems resulting in, among others, the CALM architecture which is used in NextGenITS. The project focuses on the scalability issues of routing protocols and energy optimizations for cooperative vehicular ad hoc network (VANET) systems. The resulting solutions will be simulated using TraNS and Nsclick. Afterwards the architecture and routing protocols will be tested in real life on small and large scale. }
  }
  
  Abstract:
  In the past research has been done on cooperative systems resulting in, among others, the CALM architecture which is used in NextGenITS. The project focuses on the scalability issues of routing protocols and energy optimizations for cooperative vehicular ad hoc network (VANET) systems. The resulting solutions will be simulated using TraNS and Nsclick. Afterwards the architecture and routing protocols will be tested in real life on small and large scale.

• anyMAC: adapting the Sun SPOT architecture for MAC development
  Daniel van den Akker, Bart Braem & Chris Blondia
  16th Annual Symposium on Communications and Vehicular Technology in the Benelux, Louvain-la-Neuve, Belgium, 2009.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{ieee_cvt_16,
  author = { Daniel van den Akker and Bart Braem and Chris Blondia},
  title = {anyMAC: adapting the Sun SPOT architecture for MAC development},
  booktitle = {16th Annual Symposium on Communications and Vehicular Technology in the Benelux},
  year = {2009},
  month = {NOV},
  location = {Louvain-la-Neuve, Belgium},
  URL = {content/publications/2009/dvdakker09anyMAC.pdf},
  abstract = {The Sun SPOT platform allows sensor network nodes to be programmed in Java and is therefore well suited for prototyping new sensor network protocols. The design of the Sun SPOT network stack however, makes it hard to replace the default IEEE 802.15.4 based MAC implementation. We therefore introduce the `anyMAC project': a number of alterations to the default Sun SPOT network stack. The resulting `anyMAC network stack' allows MAC implementations to be easily interchanged and provides the exibility needed to allow new MAC implementations to be developed, as demonstrated by a proof of concept `DemoMAC' MAC implementation. Performance tests show that this exibility is achieved with a very acceptable performance loss. At MAC level, the round trip time of the anyMAC network stack differs by only 12% from that of the Sun SPOT network stack, while the throughput is only marginally
  affected.}
  }
  
  Abstract:
  The Sun SPOT platform allows sensor network nodes to be programmed in Java and is therefore well suited for prototyping new sensor network protocols. The design of the Sun SPOT network stack however, makes it hard to replace the default IEEE 802.15.4 based MAC implementation. We therefore introduce the anyMAC project : a number of alterations to the default Sun SPOT network stack. The resulting anyMAC network stack allows MAC implementations to be easily interchanged and provides the exibility needed to allow new MAC implementations to be developed, as demonstrated by a proof of concept DemoMAC MAC implementation. Performance tests show that this exibility is achieved with a very acceptable performance loss. At MAC level, the round trip time of the anyMAC network stack differs by only 12% from that of the Sun SPOT network stack, while the throughput is only marginally

• A Unified Model for Synchronous and Asynchronous FDL Buffers allowing Closed-Form Solution
  W. Rogiest, J. Lambert, D. Fiems, B. Van Houdt, H. Bruneel & C. Blondia
  Performance Evaluation, Vol. 66, No. 7, pp. 343-355, 2009.
  BibTeX | PDF Available
  
  Bibtex:
  @article{jlambert2009performance,
  author = {W. Rogiest and J. Lambert and D. Fiems and B. Van Houdt and H. Bruneel and C. Blondia},
  title = {A Unified Model for Synchronous and Asynchronous FDL Buffers allowing Closed-Form Solution},
  journal = {Performance Evaluation },
  year = {2009},
  volume = {66},
  number = {7},
  pages = {343-355},
  URL = {content/publications/2009/jlambert2009performance.pdf}
  }
  
  Abstract:
  Not available

• Designing replenishment rules in a two-echelon supply chain with a flexible or an inflexible capacity strategy
  R.N. Boute, S.M. Disney, M.R. Lambrecht & B. Van Houdt
  International Journal of Production Economics, Vol. 119, No. 1, pp. 187-198, 2009.
  BibTeX | PDF Available
  
  Bibtex:
  @article{bvhoudt2009rboute,
  author={R.N. Boute and S.M. Disney and M.R. Lambrecht and B. Van Houdt },
  title = {Designing replenishment rules in a two-echelon supply chain with a flexible or an inflexible capacity strategy},
  journal = {International Journal of Production Economics },
  volume = {119},
  number = {1},
  pages = {187-198},
  year = {2009},
  URL = {content/publications/2009/bvhoudt2009rboute.pdf}
  }
  
  Abstract:
  Not available

• Mutual Assistance Community for AAL
  V. De Florio & Hong Sun
  invited presentation at the ACCESS-IT 2009 workshop ICT for Aging, London, 2009.
  BibTeX
  
  Bibtex:
  @Misc{DeSu09,
  author = {V. De Florio, Hong Sun},
  title = {Mutual Assistance Community for AAL},
  booktitle = {invited presentation at the ACCESS-IT 2009 workshop ICT for Aging},
  location = {London},
  year = {2009},
  month = {September},
  day = {23},
  }
  
  Abstract:
  Not available

• Exploiting restricted transitions in Quasi-Birth-and-Death processes
  J. F. Pérez & B. Van Houdt
  Proceedings of the QEST 2009, Budapest, Hungary, pp. 123-132, 2009.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{perevanh09qest,
  author = {J. F. P{\'e}rez and B. {Van Houdt}},
  title = {Exploiting restricted transitions in Quasi-Birth-and-Death processes},
  booktitle = {Proceedings of the QEST 2009},
  pages ={123--132},
  year = {2009},
  month = {SEP},
  location = {Budapest, Hungary},
  URL = {content/publications/2009/PerezVanHoudt_QEST2009.pdf},
  abstract = {In this paper we consider Quasi-Birth-and-Death (QBD) processes where the upward (resp. downward) transitions are restricted to occur only from (resp. to) a subset of the phase space. This property is exploited to reduce the computation time to find the matrix R or G of the process. The reduction is done through the definition of a censored process which can be of the M/G/1- or GI/M/1-type. The approach is illustrated through examples that show the applicability and benefits of making use of the additional structure. The examples also show how these special structures arise naturally in the analysis of queuing systems. Even more substantial gains can be realized when we further restrict the class of QBD processes under consideration.}
  }
  
  Abstract:
  In this paper we consider Quasi-Birth-and-Death (QBD) processes where the upward (resp. downward) transitions are restricted to occur only from (resp. to) a subset of the phase space. This property is exploited to reduce the computation time to find the matrix R or G of the process. The reduction is done through the definition of a censored process which can be of the M/G/1- or GI/M/1-type. The approach is illustrated through examples that show the applicability and benefits of making use of the additional structure. The examples also show how these special structures arise naturally in the analysis of queuing systems. Even more substantial gains can be realized when we further restrict the class of QBD processes under consideration.

• Characterization of On-Body Communication Channel and Energy Efficient Topology Design for Wireless Body Area Networks
  Elisabeth Reusens, Wout Joseph, Benoît Latré, Bart Braem, Günter Vermeeren, Luc Martens, Ingrid Moerman & Chris Blondia
  IEEE Transactions on Information Technology in Biomedicine, Vol. 13, No. 6, pp. 933-945, IEEE Press, 2009.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @article{bbraem2009titb,
  author = {Elisabeth Reusens and Wout Joseph and
  Beno{\^i}t Latr{\'e} and Bart Braem and G{\"u}nter Vermeeren and Luc Martens and Ingrid Moerman and Chris Blondia},
  title = {Characterization of On-Body Communication Channel and Energy Efficient Topology Design for Wireless Body Area Networks},
  journal = {IEEE Transactions on Information Technology in Biomedicine },
  abstract = {Wireless Body Area Networks (WBAN) offer many promising new applications in the area of remote health monitoring. An important element in the development of a WBAN is the characterization of the physical layer of the network, including an estimation of the delay spread and the path loss between two nodes on the body. This paper discusses the propagation channel between two half-wavelength dipoles at 2.45~GHz, placed near a human body and presents an application for cross-layer design in order to optimize the energy consumption of different topologies. Propagation measurements are performed on real humans in a multipath environment, considering different parts of the body separately. In addition, path loss has been numerically investigated with an anatomically correct model of the human body in free space using a 3D electromagnetic solver.
  Path loss parameters and time domain channel characteristics are extracted from the measurement and simulation data. A semi-empirical path loss model is presented for an antenna height above the body of 5~mm and antenna separations from 5~cm up to 40~cm. A time domain analysis is performed and models are presented for the mean excess delay and the delay spread.
  As a cross-layer application, the proposed path loss models are used to evaluate the energy efficiency of single-hop and multi-hop network topologies.
  },
  volume={13},
  number={6},
  pages={933--945},
  year={2009},
  publisher={IEEE Press},
  URL = {content/publications/2009/bbraem2009IEEE_TITB.pdf}
  }
  
  Abstract:
  Wireless Body Area Networks (WBAN) offer many promising new applications in the area of remote health monitoring. An important element in the development of a WBAN is the characterization of the physical layer of the network, including an estimation of the delay spread and the path loss between two nodes on the body. This paper discusses the propagation channel between two half-wavelength dipoles at 2.45~GHz, placed near a human body and presents an application for cross-layer design in order to optimize the energy consumption of different topologies. Propagation measurements are performed on real humans in a multipath environment, considering different parts of the body separately. In addition, path loss has been numerically investigated with an anatomically correct model of the human body in free space using a 3D electromagnetic solver. loss parameters and time domain channel characteristics are extracted from the measurement and simulation data. A semi-empirical path loss model is presented for an antenna height above the body of 5~mm and antenna separations from 5~cm up to 40~cm. A time domain analysis is performed and models are presented for the mean excess delay and the delay spread. a cross-layer application, the proposed path loss models are used to evaluate the energy efficiency of single-hop and multi-hop network topologies.

• ACCADA: A Framework for Continuous Context-Aware Deployment and Adaptation
  N. Gui, H. Sun, V. De Florio, & C. Blondia
  Proceedings of the 11th International Symposium on Stabilization, Safety, and Security of Distributed Systems (SSS 2009), Lecture Notes in Computer Science, Springer, 2009.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{NDFHB09d,
  author = {N. Gui, H. Sun, V. De Florio, and C. Blondia},
  title = {ACCADA: A Framework for Continuous Context-Aware Deployment and Adaptation},
  booktitle = {Proceedings of the 11th International Symposium on Stabilization, Safety, and Security of Distributed Systems (SSS 2009), Lecture Notes in Computer Science},
  address = {Lyon, France},
  year = {2009},
  month = {November},
  day = {3--6},
  publisher = {Springer},
  url = {http://euterpe.cmi.ua.ac.be/~vincenz/sssv2.01.pdf}
  }
  
  Abstract:
  Not available

• An Architecture-based Framework for Managing Adaptive Real-time Applications
  N. Gui, H. Sun, V. De Florio, & C. Blondia
  Proceedings of the 35th EUROMICRO Conference on Software Engineering and Advanced Applications (SEAA), IEEE, 2009.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{NDFHB09c,
  author = {N. Gui, H. Sun, V. De Florio, and C. Blondia},
  title = {An Architecture-based Framework for Managing Adaptive Real-time Applications},
  booktitle = {Proceedings of the 35th EUROMICRO Conference on Software Engineering and Advanced Applications (SEAA)},
  address = {Patras, Greece},
  year = {2009},
  month = {August},
  day = {27--29},
  publisher = {IEEE},
  url = {http://euterpe.cmi.ua.ac.be/~vincenz/SEEA2009.pdf}
  }
  
  Abstract:
  Not available

• Self-organisation in wireless networks - use cases and their interrelations
  L.C. Schmelz, J.L. van den Berg, R. Litjens, K. Zetterberg, M. Amirijoo, K. Spaey, I. Balan, N. Scully & S. Stefanski
  Proceedings of Wireless World Research Forum Meeting 22, Paris, France, 2009.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{WWRF22,
  author = {L.C. Schmelz, J.L. van den Berg, R. Litjens, K. Zetterberg, M. Amirijoo, K. Spaey, I. Balan, N. Scully, S. Stefanski},
  title = {Self-organisation in wireless networks - use cases and their interrelations},
  booktitle = {Proceedings of Wireless World Research Forum Meeting 22},
  year = {2009},
  month = may
  location = {Paris, France},
  URL = {content/publications/2009/SOCRATES_2009_WWRF-22.pdf}
  }
  
  Abstract:
  Not available

• On the Maximum Stable Throughput of Tree Algorithms with Free Access
  G. T. Peeters & B. Van Houdt
  IEEE Transactions on Information Theory, Vol. 55, No. 11, pp. 5087-5099, 2009.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @article{gpeeters2009tit,
  author = {G. T. Peeters and B. Van Houdt},
  title = {On the Maximum Stable Throughput of Tree Algorithms with Free Access},
  journal = {IEEE Transactions on Information Theory },
  year = {2009},
  volume = {55},
  number = {11},
  month = nov,
  pages = {5087--5099},
  URL = {content/publications/2009/gpeeters2009tit.pdf},
  abstract = {A simple numerical procedure is presented to determine the maximum stable throughput (MST) of various tree algorithms with free access
  by defining an associated multitype branching process such that the criticality of the branching process corresponds
  to the stability of the tree algorithm. More precisely, a bisection algorithm is proposed that only requires the computation
  of the dominant eigenvalue of the expectation matrix of the branching process, the size of which is typically below 20, at each step.
  Using this novel approach, many existing results on free access tree algorithms are reproduced without much effort
  (e.g., channels with/without noise, variable length packets, interference cancellation, etc.).
  Furthermore, in an almost plug-and-play manner, the MST of the free access equivalent
  of many existing results on tree algorithms with blocked access is established (e.g., channels with capture, control signals, multi reception
  capabilities, etc.). The method can be applied to the class of independent and identically distributed arrival processes, which includes the
  Poisson process as a special case. Apart from determining the MST, the probability that a size i collision is resolved in a finite amount
  of time when the arrival rate exceeds the MST, can also be computed.
  Some limitations of the proposed methodology are discussed as well.
  }
  }
  
  Abstract:
  A simple numerical procedure is presented to determine the maximum stable throughput (MST) of various tree algorithms with free access defining an associated multitype branching process such that the criticality of the branching process corresponds the stability of the tree algorithm. More precisely, a bisection algorithm is proposed that only requires the computation the dominant eigenvalue of the expectation matrix of the branching process, the size of which is typically below 20, at each step. this novel approach, many existing results on free access tree algorithms are reproduced without much effort channels with/without noise, variable length packets, interference cancellation, etc.). in an almost plug-and-play manner, the MST of the free access equivalent many existing results on tree algorithms with blocked access is established (e.g., channels with capture, control signals, multi reception etc.). The method can be applied to the class of independent and identically distributed arrival processes, which includes the process as a special case. Apart from determining the MST, the probability that a size i collision is resolved in a finite amount time when the arrival rate exceeds the MST, can also be computed. limitations of the proposed methodology are discussed as well.

• On the Design of Adaptive-and-dependable Systems---Lessons learned and experiences at the University of Antwerp
  V. De Florio & Chris Blondia
  invited talk at DSN 2009 Workshop on Architecting Dependable Systems, Theme: Architectures for Mobile and Ubiquitous Systems, Estoril, Lisboa --- Portugal, 2009.
  BibTeX | PDF Available
  
  Bibtex:
  @Misc{DeBl09a,
  author = {V. De Florio, Chris Blondia},
  title = {On the Design of Adaptive-and-dependable Systems---Lessons learned and experiences at the University of Antwerp},
  booktitle = {invited talk at DSN 2009 Workshop on
  Architecting Dependable Systems, Theme: Architectures for Mobile and Ubiquitous Systems},
  howpublished= {http://www.cs.kent.ac.uk/events/conf/2009/wads/Slides/deflorio.pdf},
  url = {http://www.cs.kent.ac.uk/events/conf/2009/wads/Slides/deflorio.pdf},
  location = {Estoril, Lisboa --- Portugal},
  year = {2009},
  month = {June},
  day = {29},
  }
  
  Abstract:
  Not available

• Analyzing and Improving Reliability in Multi-hop Body Sensor Networks
  Bart Braem, Benoît Latré, Chris Blondia, Ingrid Moerman & Piet Demeester
  International Journal On Advances in Internet Technology, ISSN 1942-2652, pp. 152-162, 2009.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{bbraem09improvingreliabilityinbsns,
  author = {Bart Braem and Beno{\^i}t Latr{\'e} and Chris Blondia and Ingrid Moerman and Piet Demeester},
  title = {Analyzing and Improving Reliability in Multi-hop Body Sensor Networks},
  booktitle = {International Journal On Advances in Internet Technology, ISSN 1942-2652},
  year = {2009
  pages = {152--162},
  URL = {content/publications/2009/bbraem09improvingreliabilityinbsns.pdf},
  abstract = {Body Sensor Networks are an interesting emerging application of wireless sensor networks to improve healthcare and the Quality of Life. Current research has mainly focused on single-hop networks, although some works clearly show advantages of multi-hop architectures. In this paper, we model probabilistic connectivity in such multi-hop body sensor networks. Instead of using a circular coverage area, a more accurate model is defined based on the path loss along the human body. Further, we propose improvements to CICADA, a cross-layer multi-hop protocol that handles both medium access and the routing of data in BSNs. CICADA is slot-based and uses schemes to allocate these slots. Results for two reliability improvements are given: randomization of the schemes and repeating the schemes received from a parent node. We show that these improvements positively affect the throughput of the network and lead to fewer retransmissions while the energy consumption of the nodes is hardly influenced.},
  }
  
  Abstract:
  Body Sensor Networks are an interesting emerging application of wireless sensor networks to improve healthcare and the Quality of Life. Current research has mainly focused on single-hop networks, although some works clearly show advantages of multi-hop architectures. In this paper, we model probabilistic connectivity in such multi-hop body sensor networks. Instead of using a circular coverage area, a more accurate model is defined based on the path loss along the human body. Further, we propose improvements to CICADA, a cross-layer multi-hop protocol that handles both medium access and the routing of data in BSNs. CICADA is slot-based and uses schemes to allocate these slots. Results for two reliability improvements are given: randomization of the schemes and repeating the schemes received from a parent node. We show that these improvements positively affect the throughput of the network and lead to fewer retransmissions while the energy consumption of the nodes is hardly influenced.,

• Adaptation Strategies for Performance Failure Avoidance
  H. Sun, V. De Florio, N. Gui, & C. Blondia
  Proceedings of the 3rd IEEE International Conference on Secure Software Integration and Reliability Improvement (SSIRI 2009), IEEE, 2009.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{SDFB09b,
  author = {H. Sun, V. De Florio, N. Gui, and C. Blondia},
  title = {Adaptation Strategies for Performance Failure Avoidance},
  booktitle = {Proceedings of the 3rd IEEE International Conference on Secure Software Integration and Reliability Improvement (SSIRI 2009)},
  address = {Shanghai, China},
  year = {2009},
  month = {July},
  day = {8--10},
  publisher = {IEEE},
  url = {content/publications/2009/adas09.pdf}
  }
  
  Abstract:
  Not available

• Dimensioning an OBS switch with Partial Wavelength Conversion and Fiber Delay Lines via a Mean Field Model
  J. F. Pérez & B. Van Houdt
  Proceedings of the IEEE Infocom 2009, Rio de Janeiro, Brazil, pp. 2651-2655, 2009.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{perevanh09infocom,
  author = {J. F. P{\'e}rez and B. {Van Houdt}},
  title = {Dimensioning an OBS switch with Partial Wavelength Conversion and Fiber Delay Lines via a Mean Field Model},
  booktitle = {Proceedings of the IEEE Infocom 2009},
  pages = {2651--2655},
  year = {2009},
  month = {APR},
  location = {Rio de Janeiro, Brazil},
  URL = {content/publications/2009/Infocom09.pdf},
  abstract = {In this paper we introduce a mean field model to analyze an optical switch equipped with both wavelength converters (WCs) and fiber delay lines (FDLs) to resolve contention in OBS networks. Under some very general conditions, that is, a general burst size distribution and any Markovian burst arrival process at each wavelength, this model
  determines the minimum number of WCs required to achieve a zero loss rate as the number of wavelengths becomes large.
  The mean field result is exact as the number of wavelengths goes to infinity and
  turns out to be very accurate for systems with (a few) hundred wavelengths, commonly occurring when using wavelength division multiplexing (WDM).
  Moreover, we show that if the number of WCs is underdimensioned, (i) periodic system behavior may occur (with the period being the greatest common divisor
  of the burst lengths) and (ii) increasing the number of WCs may even worsen the loss rate under the often studied minimum horizon allocation policy
  (as opposed to the minimum gap policy). Finally, we further demonstrate that in terms of the loss rate, including (more) FDLs may have little or no effect on the
  number of WCs required to achieve a near-zero loss, especially for high loads.}
  }
  
  Abstract:
  In this paper we introduce a mean field model to analyze an optical switch equipped with both wavelength converters (WCs) and fiber delay lines (FDLs) to resolve contention in OBS networks. Under some very general conditions, that is, a general burst size distribution and any Markovian burst arrival process at each wavelength, this model the minimum number of WCs required to achieve a zero loss rate as the number of wavelengths becomes large. mean field result is exact as the number of wavelengths goes to infinity and out to be very accurate for systems with (a few) hundred wavelengths, commonly occurring when using wavelength division multiplexing (WDM). we show that if the number of WCs is underdimensioned, (i) periodic system behavior may occur (with the period being the greatest common divisor the burst lengths) and (ii) increasing the number of WCs may even worsen the loss rate under the often studied minimum horizon allocation policy opposed to the minimum gap policy). Finally, we further demonstrate that in terms of the loss rate, including (more) FDLs may have little or no effect on the of WCs required to achieve a near-zero loss, especially for high loads.

• Wavelength Allocation in an Optical Switch with a Fiber Delay Line Buffer and Limited-Range Wavelength Conversion
  J. F. Pérez & B. Van Houdt
  Telecommunication Systems, Vol. 41, No. 1, pp. 37-49, 2009.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @ARTICLE{perevanh09limited,
  author = {J. F. P{\'e}rez and B. {Van Houdt}},
  title = {Wavelength Allocation in an Optical Switch with a Fiber Delay Line Buffer and Limited-Range Wavelength Conversion},
  booktitle = {Telecommunication Systems},
  volume = {41},
  number = {1},
  pages = {37--49},
  year = {2009},
  month = {MAY},
  URL = {content/publications/2009/perevanh09limited.pdf},
  abstract = {This paper presents an approach to evaluate the performance of an optical switch equipped with both limited-range wavelength conversion and Fiber Delay Lines to resolve contention. We propose an analytical model that allows a general behavior for the packet size distribution while the inter-arrival times are assumed to be of Phase-Type and can easily be relaxed to be generally distributed if needed. As the set of reachable wavelengths is a major issue in limited-range wavelength conversion, we first focus on a simple wavelength set configuration that allows the comparison of different policies and their effect on the loss rate of the system. In addition, a linear association between the loss rate of the simple and a more complex set configuration is identified. Using this association and the results from the analytical model, we derive an approximation for the more complex case, where the interactions among adjacent wavelengths play an important role. The approximation works well for different parameter instances and is particularly useful for the mid load case, when simulations become computationally prohibitive.}
  }
  
  Abstract:
  This paper presents an approach to evaluate the performance of an optical switch equipped with both limited-range wavelength conversion and Fiber Delay Lines to resolve contention. We propose an analytical model that allows a general behavior for the packet size distribution while the inter-arrival times are assumed to be of Phase-Type and can easily be relaxed to be generally distributed if needed. As the set of reachable wavelengths is a major issue in limited-range wavelength conversion, we first focus on a simple wavelength set configuration that allows the comparison of different policies and their effect on the loss rate of the system. In addition, a linear association between the loss rate of the simple and a more complex set configuration is identified. Using this association and the results from the analytical model, we derive an approximation for the more complex case, where the interactions among adjacent wavelengths play an important role. The approximation works well for different parameter instances and is particularly useful for the mid load case, when simulations become computationally prohibitive.

• Adaptive Robot Design and Applications in Flexible Manufacturing Environments
  Ning Gui, Vincenzo De Florio, Hong Sun & Chris Blondia
  13th IFAC Symposium on Information Control Problems in Manufacturing (INCOM 09), 2009.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{GDSB09a,
  author = {Ning Gui, Vincenzo De Florio, Hong Sun, Chris Blondia},
  title = {Adaptive Robot Design and Applications in Flexible
  Manufacturing Environments},
  year = {2009},
  booktitle = {13th IFAC Symposium on Information Control
  Problems in Manufacturing (INCOM '09)},
  address = {Moskow, Russia},
  month = {June},
  day = {3--5},
  url = {content/publications/2009/adrod09.pdf}
  }
  
  Abstract:
  Not available

• Multiple Access Algorithms without Feedback using Combinatorial Designs
  G. T. Peeters, R. Bocklandt & B. Van Houdt
  IEEE Transactions on Communications, Vol. 57, No. 9, pp. 2724-2733, 2009.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @article{gpeeters2009tcom,
  author = {G. T. Peeters and R. Bocklandt and B. Van Houdt},
  title = {Multiple Access Algorithms without Feedback using Combinatorial Designs},
  journal = {IEEE Transactions on Communications },
  volume = {57},
  number = {9},
  year = {2009},
  month = sep,
  pages = { 2724--2733},
  URL = {content/publications/2009/Peeters_ToC_42_REVISED_VERSION.pdf},
  abstract = {A new class of multiple access algorithms for systems without feedback is introduced and analyzed. A finite population of users is assumed, where each user transmits a packet R times within the next N time slots (and all packets have an equal length of one slot). To improve the performance achieved by randomly selecting these R slots, user codes are invokedsuch that any two users will only transmit simultaneously in at most one slot, i.e., 2-(N,R,1) designs.
  We argue that in most cases, the set of user codes can be generated easily using cyclic designs and provide a method to select T user codes from the set of user codes S_{N,R} incase the user population consists of T<|S_{N,R}| users. We further demonstrate how larger populations, with T>|S_{N,R}|, can still benefit from these user codes in two different manners. Closed formulas that express the success probability of a packet are provided for all population setups.
  Finally, a comparison with the random selection strategy demonstrates the performance gain realized by the new multiple access algorithms and some engineering rules to optimize the performance are provided.
  }
  }
  
  Abstract:
  A new class of multiple access algorithms for systems without feedback is introduced and analyzed. A finite population of users is assumed, where each user transmits a packet R times within the next N time slots (and all packets have an equal length of one slot). To improve the performance achieved by randomly selecting these R slots, user codes are invokedsuch that any two users will only transmit simultaneously in at most one slot, i.e., 2-(N,R,1) designs. argue that in most cases, the set of user codes can be generated easily using cyclic designs and provide a method to select T user codes from the set of user codes S_N,R incase the user population consists of T<|S_N,R| users. We further demonstrate how larger populations, with T>|S_N,R|, can still benefit from these user codes in two different manners. Closed formulas that express the success probability of a packet are provided for all population setups. a comparison with the random selection strategy demonstrates the performance gain realized by the new multiple access algorithms and some engineering rules to optimize the performance are provided.

• WBAN implementation on Magnetic Induction Radio IC for medical remote monitoring
  Wim Torfs, Peter De Cleyn & Chris Blondia
  Accepted at the 1st International Workshop on Medical Applications Networking, Dresden, Germany, 2009.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{im309,
  author = {Wim Torfs, Peter De Cleyn and Chris Blondia},
  title = {WBAN implementation on Magnetic Induction Radio IC for medical remote monitoring},
  booktitle = {Accepted at the 1st International Workshop on Medical Applications Networking},
  year = {2009},
  month = {JUN},
  location = {Dresden, Germany},
  url = {content/publications/2009/im3_impl_man_2009.pdf},
  abstract = {The medical service environment is changing. There is a need for automatization of collecting medical data remotely from the patient. Telecare is the continuous remote monitoring of the health of the patient. The IM3 (Interactive Mobile Medical Monitoring) project focuses on developing and implementing such end-to-end service. We implemented the WBAN (Wireless Body Area Network) protocol on the Magnetic Induction Radio IC (Integrated Circuit), which is designed by NXP Semiconductors. We show in this paper that we have a working setup, where nodes form autonomously the network and send ECG data to the sink.},
  }
  
  Abstract:
  The medical service environment is changing. There is a need for automatization of collecting medical data remotely from the patient. Telecare is the continuous remote monitoring of the health of the patient. The IM3 (Interactive Mobile Medical Monitoring) project focuses on developing and implementing such end-to-end service. We implemented the WBAN (Wireless Body Area Network) protocol on the Magnetic Induction Radio IC (Integrated Circuit), which is designed by NXP Semiconductors. We show in this paper that we have a working setup, where nodes form autonomously the network and send ECG data to the sink.,

• Promises and Challenges of Ambient Assisted Living Systems
  Hong Sun, Vincenzo De Florio, Ning Gui & Chris Blondia
  Proceedings of the 6th International Conference on Information Technology: New Generations (ITNG 2009), Las Vegas, Nevada, USA, 2009.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{SDGB09a,
  author = {Hong Sun, Vincenzo De Florio, Ning Gui, Chris Blondia},
  title = {Promises and Challenges of Ambient Assisted Living Systems},
  booktitle = {Proceedings of the 6th International Conference on Information Technology: New Generations (ITNG 2009)},
  year = {2009},
  month = {April},
  day = {27--29},
  location = {Las Vegas, Nevada, USA},
  URL = {content/publications/2009/prochaAAL.pdf}
  }
  
  Abstract:
  Not available

• Application-layer Fault-tolerance Protocols
  Vincenzo De Florio
  pp. 378, IGI Global, 2009.
  BibTeX | PDF Available
  
  Bibtex:
  @Book{D09,
  author = {Vincenzo De Florio},
  title = {Application-layer Fault-tolerance Protocols},
  publisher = {IGI Global},
  address = {Hershey, PA 17033, USA},
  year = {2009},
  pages = {378},
  url = {http://www.igi-global.com/downloads/pdf/32917.pdf}
  }
  
  Abstract:
  Not available

• Quality of Service through Bandwidth Reservation on Multirate Ad-hoc Wireless Networks
  M. Voorhaen, C. Blondia, R. Guimarães, L. Cerdà, J.M. Barceló & J. García
  Ad Hoc Networks Journal, Volume 7 Issue 2, p. 388-400, 2009.
  BibTeX | Abstract
  
  Bibtex:
  @JOURNAL{mvhaen08adhoc,
  author = {M. Voorhaen and C. Blondia and R. Guimar{\^a}es and L. Cerd{\`a} and J.M. Barcel{\'o} and J. Garc{\'i}a},
  title = {Quality of Service through Bandwidth Reservation on Multirate Ad-hoc Wireless Networks},
  booktitle = {Ad Hoc Networks Journal, Volume 7 Issue 2, p. 388-400},
  year = {2009},
  abstract = {Achieving QoS (Quality of Service) in Ad-hoc Wireless Networks (AWNs) has been a research topic in the last years. In this paper we describe a QoS reservation mechanism for Multirate AWNs that allows bandwidth allocation on a per flow basis. By multirate we refer to those networks where wireless nodes are able to dynamically switch among several link rates. This allows nodes to select the highest possible transmission rate for exchanging data, independently for each neighbor.
  }
  }
  
  Abstract:
  Achieving QoS (Quality of Service) in Ad-hoc Wireless Networks (AWNs) has been a research topic in the last years. In this paper we describe a QoS reservation mechanism for Multirate AWNs that allows bandwidth allocation on a per flow basis. By multirate we refer to those networks where wireless nodes are able to dynamically switch among several link rates. This allows nodes to select the highest possible transmission rate for exchanging data, independently for each neighbor.

2008

• A Hessenberg Markov chain for fast Fibre Delay Line length optimization
  J. Lambert, W. Rogiest, B. Van Houdt, D. Fiems, C. Blondia & H. Bruneel
  Lecture Notes in Computer Science (LNCS 5055): Analytical and stochastic modeling techniques and applications, ASMTA 2008, Nicosia (Cyprus), pp. 101-113, 2008.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{asmta2008,
  author = {J. Lambert, W. Rogiest, B. Van Houdt, D. Fiems, C. Blondia, H. Bruneel},
  title = {A Hessenberg Markov chain for fast Fibre Delay Line length optimization},
  booktitle = {Lecture Notes in Computer Science (LNCS 5055): Analytical and stochastic modeling techniques and applications, ASMTA 2008},
  pages = {101-113},
  year = {2008},
  location = {Nicosia (Cyprus)},
  URL = {content/publications/2008/ASMTA2008.pdf}
  }
  
  Abstract:
  Not available

• Towards longer, better and more active lives: mutual assisted living community for older people
  Hong Sun, Vincenzo De Florio, Ning Gui & Chris Blondia
  Journal of the Institute of Telecommunications Professionals, Vol. 2, No. 4, 2008.
  BibTeX | PDF Available
  
  Bibtex:
  @Article{SDGB08z,
  author = {Hong Sun and Vincenzo De Florio and Ning Gui and Chris Blondia},
  title = {Towards longer, better and more active lives: mutual assisted living community for older people},
  journal = {Journal of the Institute of Telecommunications Professionals},
  volume = {2},
  number = {4},
  year = {2008},
  url = {content/publications/2008/fitce08.pdf}
  }
  
  Abstract:
  Not available

• SCTP as mobility protocol for enhancing Internet on the train
  Daan Pareit, Ingrid Moerman, Piet Demeester, Wim Torfs, Peter De Cleyn & Chris Blondia
  Proceedings of the 8th International Conference on ITS Telecommunications, Hilton Phuket, Thailand, 2008.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{trains08,
  author = {Daan Pareit, Ingrid Moerman, Piet Demeester, Wim Torfs, Peter De Cleyn and Chris Blondia},
  title = {SCTP as mobility protocol for enhancing
  Internet on the train},
  booktitle = {Proceedings of the 8th International Conference on ITS Telecommunications},
  year = {2008},
  month = {OKT},
  location = {Hilton Phuket, Thailand},
  url = {content/publications/2008/wtorfs_ITST2008.pdf},
  abstract = {Internet-on-the-train is a rising concept in the last few years. Several trials in different countries have proved the feasibility of offering Internet access to train commuters, but none of them combines broadband access, scalability, seamless handover and quality of service guarantees in one solution. In this paper, we look at the features of SCTP and its extensions which could overcome these shortcomings and which were successfully demonstrated.},
  }
  
  Abstract:
  Internet-on-the-train is a rising concept in the last few years. Several trials in different countries have proved the feasibility of offering Internet access to train commuters, but none of them combines broadband access, scalability, seamless handover and quality of service guarantees in one solution. In this paper, we look at the features of SCTP and its extensions which could overcome these shortcomings and which were successfully demonstrated.,

• QoS support for a MAC with a TDMA tree topology on the Magnetic Induction Radio IC
  Wim Torfs & Chris Blondia
  Proceedings of 29th Real-Time Systems Symposium (RTSS 2008), Barcelona, Spain, 2008.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{wtorfs08RTSS,
  author = {Wim Torfs and Chris Blondia},
  title = {QoS support for a MAC with a TDMA tree
  topology on the Magnetic Induction Radio IC},
  booktitle = {Proceedings of 29th Real-Time Systems Symposium (RTSS'2008) },
  year = {2008},
  location = {Barcelona, Spain},
  url = {content/publications/2008/wtorfs_rtss_wip2008.pdf},
  abstract = {In our previous work, we implemented a TDMA tree
  based protocol on the Magnetic Induction Radio IC. The protocol was designed for Body Area Networks (BANs). The result was a protocol that worked for that specific situation, but could not be extended to other applications. The protocol needed some mechanism that would provide extra flexibility to the network. In this work, we add QoS to the protocol, which results in the protocol that can be used in several kinds of applications. The resulting protocol has the capability to be configured at runtime for the kind of sensors that are being used, in order to optimize the throughput and efficiency.}
  }
  
  Abstract:
  In our previous work, we implemented a TDMA tree protocol on the Magnetic Induction Radio IC. The protocol was designed for Body Area Networks (BANs). The result was a protocol that worked for that specific situation, but could not be extended to other applications. The protocol needed some mechanism that would provide extra flexibility to the network. In this work, we add QoS to the protocol, which results in the protocol that can be used in several kinds of applications. The resulting protocol has the capability to be configured at runtime for the kind of sensors that are being used, in order to optimize the throughput and efficiency.

• Use Cases, Requirements and Assessment Criteria for Future Self-organising Radio Access Networks
  M. Amirijoo, R. Litjens, K. Spaey, M. Döttling, T. Jansen, N. Scully & U. Türke
  Proceedings of 3rd International Workshop on Self-Organizing Systems (IWSOS 2008), Vienna, Austria, Lecture Notes in Computer Science, Vol. 5343, pp. 275-280, Springer, 2008.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{IWSOS2008,
  author = {M. Amirijoo, R. Litjens, K. Spaey, M. D{\"o}ttling, T. Jansen, N. Scully and U. T{\"u}rke},
  title = {Use Cases, Requirements and Assessment Criteria for Future Self-organising Radio Access Networks},
  booktitle = {Proceedings of 3rd International Workshop on Self-Organizing Systems (IWSOS 2008)},
  pages = {275--280},
  year = {2008},
  month = dec,
  location = {Vienna, Austria},
  series = {Lecture Notes in Computer Science},
  volume = {5343},
  publisher = {Springer},
  URL = {content/publications/2008/SOCRATES IWSOS 2008 CRC.pdf}
  }
  
  Abstract:
  Not available

• Capacity Planning in a Mobile TV Broadcast Network with Variable Bit Rate Channels: Comparison of Simulcast and SVC
  Z. Avramova, D. De Vleeschauwer, K. Spaey, S. Wittevrongel, H. Bruneel & C. Blondia
  Proceedings of International Workshop on Traffic Management and Traffic Engineering for the Future Internet (FITraMEn 08), Porto, Portugal, 2008.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{FITraMEn,
  author = {Z. Avramova, D. De Vleeschauwer, K. Spaey, S. Wittevrongel, H. Bruneel and C. Blondia},
  title = {Capacity Planning in a Mobile TV Broadcast Network with Variable Bit Rate Channels: Comparison of Simulcast and SVC},
  booktitle = {Proceedings of International Workshop on Traffic Management and Traffic Engineering for the Future Internet (FITraMEn 08)},
  year = {2008},
  month = dec,
  location = {Porto, Portugal},
  URL = {content/publications/2008/FITraMEn_S2_CR.pdf}
  }
  
  Abstract:
  Not available

• Applying Business Process Re-engineering Patterns to optimize WS-BPEL Workflows
  Jonas Buys, Vincenzo De Florio & Chris Blondia
  Proceedings of IT Revolutions 2008, Lecture Notes of ICST, Venice, Italy, Springer, 2008.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{BDB08a,
  author = {Jonas Buys, Vincenzo De Florio, Chris Blondia},
  title = {Applying Business Process Re-engineering Patterns to optimize WS-BPEL Workflows},
  booktitle = {Proceedings of IT Revolutions 2008, Lecture Notes of ICST},
  year = {2008},
  month = {December},
  day = {17--19},
  location = {Venice, Italy},
  publisher = {Springer},
  url = {content/publications/2008/Buys2008.pdf}
  }
  
  Abstract:
  Not available

• Q-MAM: A Tool for Solving Infinite Queues using Matrix-Analytic Methods
  J. F. Pérez, J. Van Velthoven & B. Van Houdt
  Proceedings of the SMCTools 2008, Athens, Greece, 2008.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{dagstuhl,
  author = {J. F. P{\'e}rez and J. Van Velthoven and B. Van Houdt},
  title = {Q-MAM: A Tool for Solving Infinite Queues using
  Matrix-Analytic Methods},
  booktitle = {Proceedings of the SMCTools 2008},
  year = {2008},
  month = {OCT},
  location = {Athens, Greece},
  URL = {content/publications/2008/Perez_VanVelthoven_VanHoudt_QMAM.pdf},
  abstract = {In this paper we propose a novel MATLAB tool, called Q-MAM, to compute queue length, waiting time and sojourn time distributions of various discrete and continuous time queuing systems with an underlying structured Markov chain/process. The underlying paradigms include M/G/1- and GI/M/1-type, quasi-birth-death and non-skip-free Markov chains (implemented by the SMCSolver tool), as well as Markov processes with a matrix exponential distribution. We consider various single server queueing systems with phase-type, matrix exponential, Markovian, rational and semi-Markovian arrival and service processes; queues with multiple customer types, where the service depends on the customer type and where consecutive customer types may be correlated; and queues with multiple servers for which the typical dimensionality problem can be avoided. Apart from implementing various classical and more advanced solution techniques, the tool also extends and improves some of the existing solution techniques in a number of cases.}
  }
  
  Abstract:
  In this paper we propose a novel MATLAB tool, called Q-MAM, to compute queue length, waiting time and sojourn time distributions of various discrete and continuous time queuing systems with an underlying structured Markov chain/process. The underlying paradigms include M/G/1- and GI/M/1-type, quasi-birth-death and non-skip-free Markov chains (implemented by the SMCSolver tool), as well as Markov processes with a matrix exponential distribution. We consider various single server queueing systems with phase-type, matrix exponential, Markovian, rational and semi-Markovian arrival and service processes; queues with multiple customer types, where the service depends on the customer type and where consecutive customer types may be correlated; and queues with multiple servers for which the typical dimensionality problem can be avoided. Apart from implementing various classical and more advanced solution techniques, the tool also extends and improves some of the existing solution techniques in a number of cases.

• A cluster driven channel assignment mechanism for wireless mesh networks
  N. Letor, S. Bouckaert, C. Blondia, I. Moerman & P. Demeester
  Proc. Second IEEE International Workshop on Enabling Technologies and Standards for Wireless Mesh Networking (MeshTech 2008) in conjunction with IEEE MASS 2008, 2008.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @ARTICLE{nletor08a,
  author = {N. Letor, S. Bouckaert, C. Blondia, I. Moerman and P. Demeester},
  title = {A cluster driven channel assignment mechanism for wireless mesh networks},
  abstract = {In this paper we present a cross layer topology preserving channel selection protocol for a two interface wireless mesh network. The presented protocol is a cluster driven channel selection protocol, preserving a single interface to maintain connectivity and using the other interface to participate in small clusters. The clusters are organized by an independent set clustering algorithm, in which the cluster head dictates the operating channel for the local cluster. We show that the channel selection algorithm doubles the capacity for both a regular grid and a random topology.},
  booktitle = {Proc. Second IEEE International Workshop on Enabling Technologies and Standards for Wireless Mesh Networking (MeshTech 2008) in conjunction with IEEE MASS 2008},
  year = {2008},
  month = {September}
  URL = {content/publications/2008/nletor08mwis.pdf}
  }
  
  Abstract:
  In this paper we present a cross layer topology preserving channel selection protocol for a two interface wireless mesh network. The presented protocol is a cluster driven channel selection protocol, preserving a single interface to maintain connectivity and using the other interface to participate in small clusters. The clusters are organized by an independent set clustering algorithm, in which the cluster head dictates the operating channel for the local cluster. We show that the channel selection algorithm doubles the capacity for both a regular grid and a random topology.

• A Low-Delay Protocol for Multihop Wireless Body Area Networks
  Benoît Latré, Bart Braem, Ingrid Moerman, Chris Blondia & Piet Demeester
  KEIO and Gent University G-COE Joint workshop for future network, Ghent, Belgium, pp. 38-45, 2008.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{Latre08Keio,
  author = {Beno{\^i}t Latr{\'e} and Bart Braem and Ingrid Moerman and Chris Blondia and Piet Demeester},
  title = {A Low-Delay Protocol for Multihop Wireless Body Area Networks},
  booktitle = {KEIO and Gent University G-COE Joint workshop for future network},
  year = {2008},
  pages = {38--45},
  location = {Ghent, Belgium},
  month = {26-27 September},
  URL = {content/publications/2007/bbraem07cicada.pdf},
  abstract = {Wireless Body Area Networks (WBANs) form a new and interesting area in the world of remote health monitoring. An important concern in such networks is the communication between the sensors. This communication needs to be energy efficient and highly reliable while keeping delays low. Mobility also has to be supported as the nodes are positioned on different parts of the body that move with regard to each other. In this paper, we present a new cross-layer communication protocol for WBANs: CICADA or Cascading Information retrieval by Controlling Access with Distributed slot Assignment. The protocol sets up a network tree in a distributed manner. This tree structure is subsequently used to guarantee collision free access to the medium and to route data towards the sink. The paper analyzes CICADA and shows simulation results. The protocol offers low delay and good resilience to mobility. The energy usage is low as the nodes can sleep in slots where they are not transmitting or receiving.}
  }
  
  Abstract:
  Wireless Body Area Networks (WBANs) form a new and interesting area in the world of remote health monitoring. An important concern in such networks is the communication between the sensors. This communication needs to be energy efficient and highly reliable while keeping delays low. Mobility also has to be supported as the nodes are positioned on different parts of the body that move with regard to each other. In this paper, we present a new cross-layer communication protocol for WBANs: CICADA or Cascading Information retrieval by Controlling Access with Distributed slot Assignment. The protocol sets up a network tree in a distributed manner. This tree structure is subsequently used to guarantee collision free access to the medium and to route data towards the sink. The paper analyzes CICADA and shows simulation results. The protocol offers low delay and good resilience to mobility. The energy usage is low as the nodes can sleep in slots where they are not transmitting or receiving.

• On the Requirements of New Software Development
  Vincenzo De Florio & Chris Blondia
  International Journal of Business Intelligence and Data Mining, Vol. 3, No. 3, Inderscience, 2008.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @Article{DeFl08,
  author = {Vincenzo De Florio, Chris Blondia},
  title = {On the Requirements of New Software Development},
  journal = {International Journal of Business Intelligence and Data Mining},
  year = {2008},
  volume = {3},
  number = {3},
  publisher={Inderscience},
  url = {content/publications/2008/adidrds.pdf},
  abstract={Changes, they use to say, are the only constant in life. Everything changes rapidly around us, and more and
  more key to survival is the ability to rapidly adapt to changes. This consideration applies to many aspects of
  our lives. Strangely enough, this nearly self-evident truth is not always considered by software engineers with the
  seriousness that it calls for: The assumptions we draw for our systems often do not take into due account that e.g.,
  the run-time environments, the operational conditions, or the available resources will vary. Software is especially
  vulnerable to this threat, and with today’s software-dominated systems controlling crucial services in nuclear plants,
  airborne equipments, health care systems and so forth, it becomes clear how this situation may potentially lead to
  catastrophes. This paper discusses this problem and defines some of the requirements towards its effective solution,
  which we call “New Software Development” as a software equivalent of the well-known concept of New Product
  Development. The paper also introduces and discusses a practical example of a software tool designed taking those
  requirements into account—an adaptive data integrity provision in which the degree of redundancy is not fixed once
  and for all at design time, but rather it changes dynamically with respect to the disturbances experienced during
  the run time.}
  }
  
  Abstract:
  Changes, they use to say, are the only constant in life. Everything changes rapidly around us, and more and key to survival is the ability to rapidly adapt to changes. This consideration applies to many aspects of lives. Strangely enough, this nearly self-evident truth is not always considered by software engineers with the that it calls for: The assumptions we draw for our systems often do not take into due account that e.g., run-time environments, the operational conditions, or the available resources will vary. Software is especially to this threat, and with today’s software-dominated systems controlling crucial services in nuclear plants, equipments, health care systems and so forth, it becomes clear how this situation may potentially lead to This paper discusses this problem and defines some of the requirements towards its effective solution, we call “New Software Development” as a software equivalent of the well-known concept of New Product The paper also introduces and discusses a practical example of a software tool designed taking those into account—an adaptive data integrity provision in which the degree of redundancy is not fixed once for all at design time, but rather it changes dynamically with respect to the disturbances experienced during run time.

• A framework for adaptive real-time applications: the declarative real-time OSGi component model
  Ning Gui, Vincenzo De Florio, Hong Sun, & Chris Blondia
  Proceedings of the 7th Workshop on Adaptive and Reflective Middleware (ARM 08), ACM/IFIP/USENIX, 2008.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{GDSB08b,
  author = {Ning Gui, Vincenzo De Florio, Hong Sun, and Chris Blondia},
  title = {A framework for adaptive real-time applications: the declarative real-time OSGi component model},
  booktitle = {Proceedings of the 7th Workshop on Adaptive and Reflective Middleware (ARM'08)},
  address = {Leuven, Belgium},
  year = {2008},
  month = {December},
  day = {1},
  publisher = {ACM/IFIP/USENIX},
  url = {content/publications/2008/adm2008.pdf}
  }
  
  Abstract:
  Not available

• Cross layer PHY-MAC protocol for wireless static and mobile ad hoc networks
  Sylwia Romaszko & Chris Blondia
  To appear in the EURASIP Journal on Advances in Signal processing, the special issue: "Cross-Layer Design for the Physical, MAC, and Link Layer in Wireless Systems", , 2008.
  BibTeX | Abstract
  
  Bibtex:
  @INPROCEEDINGS{sromaszko08Eurasip,
  author = {Sylwia Romaszko and Chris Blondia},
  title = {Cross layer PHY-MAC protocol for
  wireless static and mobile ad hoc networks},
  booktitle = {To appear in the EURASIP Journal on Advances in Signal processing, the special issue: "Cross-Layer Design for the Physical, MAC, and Link Layer in Wireless Systems"},
  year = {2008},
  location = {},
  abstract = {Multihop mobile wireless networks have
  drawn a lot of attention in recent years thanks to their
  wide applicability in civil and military environments.
  Since the existing 802.11 DCF standard does not
  provide satisfactory access to the wireless medium
  in multihop mobile networks, we have designed a
  cross layer protocol, (CroSs layer Noise Aware Power
  driven MAC (SNAPdMac)), which consists of two
  parts. The protocol first concentrates on the flexible
  adjustment of the upper and lower bounds of the
  ContentionWindow to lower the number of collisions.
  In addition, it uses a power control scheme, triggered
  by the MAC layer, to limit the waste of energy and
  also to decrease the number of collisions. Thanks
  to a noticeable energy conservation and decrease
  of the number of collisions, it prolongs significantly
  the lifetime of the network and delays the death of
  the first node while increasing both the throughput
  performance and the sending bit rate/throughput
  fairness among contending flows.}
  }
  
  Abstract:
  Multihop mobile wireless networks have a lot of attention in recent years thanks to their applicability in civil and military environments. the existing 802.11 DCF standard does not satisfactory access to the wireless medium multihop mobile networks, we have designed a layer protocol, (CroSs layer Noise Aware Power MAC (SNAPdMac)), which consists of two The protocol first concentrates on the flexible of the upper and lower bounds of the to lower the number of collisions. addition, it uses a power control scheme, triggered the MAC layer, to limit the waste of energy and to decrease the number of collisions. Thanks a noticeable energy conservation and decrease the number of collisions, it prolongs significantly lifetime of the network and delays the death of first node while increasing both the throughput and the sending bit rate/throughput among contending flows.

• Self-Organisation in Future Mobile Communication Networks
  J.L. van den Berg, R. Litjens, A. Eisenblätter, M. Amirijoo, O. Linnell, C. Blondia, T. Kürner, N. Scully, J. Oszmianski & L.C. Schmelz
  Proceedings of ICT - Mobile Summit 2008, Stockholm, Sweden, 2008.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{MobileSummit2008,
  author = {J.L. van den Berg, R. Litjens, A. Eisenbl{\"a}tter, M. Amirijoo, O. Linnell, C. Blondia, T. K{\"u}rner, N. Scully, J. Oszmianski, L.C. Schmelz},
  title = {Self-Organisation in Future Mobile Communication Networks},
  booktitle = {Proceedings of ICT - Mobile Summit 2008},
  year = {2008},
  month = jun
  location = {Stockholm, Sweden},
  URL = {content/publications/2008/SOCRATES_2008_ICT Mobile Summit.pdf}
  }
  
  Abstract:
  Not available

• Self-configuration, -optimisation and -healing in wireless networks
  L.C. Schmelz, J.L. van den Berg, R. Litjens, A. Eisenblätter, M. Amirijoo, O. Linnell, C. Blondia, T. Kürner, N. Scully & J. Oszmianski
  Proceedings of Wireless World Research Forum Meeting 20, Ottawa, Canada, 2008.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{WWRF20,
  author = {L.C. Schmelz, J.L. van den Berg, R. Litjens, A. Eisenbl{\"a}tter, M. Amirijoo, O. Linnell, C. Blondia, T. K{\"u}rner, N. Scully, J. Oszmianski},
  title = {Self-configuration, -optimisation and -healing in wireless networks},
  booktitle = {Proceedings of Wireless World Research Forum Meeting 20},
  year = {2008},
  month = apr
  location = {Ottawa, Canada},
  URL = {content/publications/2008/SOCRATES_2008_WWRF-20.pdf}
  }
  
  Abstract:
  Not available

• Towards Longer, Better, and More Active Lives - Building Mutual Assisted Living Community for Elder People
  H. Sun, V. De Florio, N. Gui, & C. Blondia
  Proceedings of the 47th European FITCE Congress, FITCE,, 2008.
  BibTeX
  
  Bibtex:
  @InProceedings{HoFITCE08,
  author = {H. Sun, V. De Florio, N. Gui, and C. Blondia},
  title = {Towards Longer, Better, and More Active Lives - Building Mutual Assisted Living Community for Elder People},
  booktitle = {Proceedings of the 47th European FITCE Congress},
  address = {Logan Hall, Bloomsbury, London},
  year = {2008},
  month = {September},
  day = {21--24},
  publisher = {FITCE},
  }
  
  Abstract:
  Not available

• Improved High Maximum Stable Throughput FCFS Tree Algorithms with Interference Cancellation
  G. T. Peeters & B. Van Houdt
  Proceedings of the 3rd International Conference on Performance Evaluation Methodologies and Tools, VALUETOOLS 2008., Athens, Greece, 2008.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{gpeeters_valuetools2008,
  author = {G. T. Peeters and B. Van Houdt},
  title = {Improved High Maximum Stable Throughput FCFS Tree Algorithms with Interference Cancellation},
  booktitle = {Proceedings of the 3rd International Conference on Performance Evaluation Methodologies and Tools, VALUETOOLS 2008.},
  year = {2008},
  month = {OCT},
  location = {Athens, Greece},
  abstract = {Tree algorithms form a well researched class of collision resolution algorithms for solving multiple access control problems. Signal interference cancellation, which allows one to
  recover additional information from otherwise lost collision signals, has recently been combined with tree algorithms, providing substantially higher maximum stable throughputs (MSTs), up to 0.693 (Yu and Giannakis, IEEE Transactions on Information Theory, Vol. 53(12), 2007).
  We propose two novel First-Come-First-Served tree algorithms, the operation of which is similar to the well-known tree splitting algorithms, that exploit interference cancellation and derive their MST. Furthermore, these algorithms are also designed such that, at all times, it suffices to store only one signal. },
  url = {content/publications/2008/gpeeters08valuetools.pdf}
  }
  
  Abstract:
  Tree algorithms form a well researched class of collision resolution algorithms for solving multiple access control problems. Signal interference cancellation, which allows one to additional information from otherwise lost collision signals, has recently been combined with tree algorithms, providing substantially higher maximum stable throughputs (MSTs), up to 0.693 (Yu and Giannakis, IEEE Transactions on Information Theory, Vol. 53(12), 2007). We propose two novel First-Come-First-Served tree algorithms, the operation of which is similar to the well-known tree splitting algorithms, that exploit interference cancellation and derive their MST. Furthermore, these algorithms are also designed such that, at all times, it suffices to store only one signal.

• Improving Reliability in Multi-hop Body Sensor Networks
  Bart Braem, Benoît Latré, Chris Blondia, Ingrid Moerman & Piet Demeester
  Sensor Technologies and Applications, 2008. SENSORCOMM 08. Second International Conference on, Cap Esterel, France, pp. 342-347, 2008.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{bbraem08improvingreliabilityinbsns,
  author = {Bart Braem and Beno{\^i}t Latr{\'e} and Chris Blondia and Ingrid Moerman and Piet Demeester},
  title = {Improving Reliability in Multi-hop Body Sensor Networks},
  booktitle = {Sensor Technologies and Applications, 2008. {SENSORCOMM} '08. Second International Conference on},
  year = {2008},
  pages = {342--347},
  location = {Cap Esterel, France},
  month = {AUG},
  day = {25--31},
  URL = {content/publications/2008/bbraem08improvingreliabilityinbsns.pdf},
  abstract = {Body Sensor Networks are an interesting emerging application of wireless sensor networks to improve healthcare and the Quality of Life. Current research has mainly focused on singlehop~networks, although some works clearly show advantages of multihop~architectures. In this paper, we model probabilistic connectivity in such multihop~body sensor networks. Instead of using a circular coverage area, a more accurate model is defined based on the path loss along the human body. Further, we propose improvements to CICADA, a cross-layer multihop protocol that handles both medium access and the routing of data in BSNs. CICDA is slot-based and uses schemes to allocate these slots. Preliminary results for two reliability improvements are given: randomization of the schemes and repeating the schemes received from a parent node. We show that these improvements positively affect the throughput of the network and lead to fewer retransmissions. In both cases, the energy consumption of the nodes is hardly influenced.},
  doi = {10.1109/SENSORCOMM.2008.47},
  }
  
  Abstract:
  Body Sensor Networks are an interesting emerging application of wireless sensor networks to improve healthcare and the Quality of Life. Current research has mainly focused on singlehop~networks, although some works clearly show advantages of multihop~architectures. In this paper, we model probabilistic connectivity in such multihop~body sensor networks. Instead of using a circular coverage area, a more accurate model is defined based on the path loss along the human body. Further, we propose improvements to CICADA, a cross-layer multihop protocol that handles both medium access and the routing of data in BSNs. CICDA is slot-based and uses schemes to allocate these slots. Preliminary results for two reliability improvements are given: randomization of the schemes and repeating the schemes received from a parent node. We show that these improvements positively affect the throughput of the network and lead to fewer retransmissions. In both cases, the energy consumption of the nodes is hardly influenced.

• A Secure Cross-layer Protocol for Multi-hop Wireless Body Area Networks
  Dave Singelée, Benoît Latré, Bart Braem, Michael Peeters, Marijke De Soete, Peter De Cleyn, Bart Preneel, Ingrid Moerman & Chris Blondia
  Ad-hoc, Mobile and Wireless Networks, Sophia Antipolis, France, Lecture Notes in Computer Science, Vol. 5198, pp. 94-107, Springer Berlin / Heidelberg, 2008.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @inproceedings{bbraem08securewbanprotocol,
  author = {Dave Singel{\'e}e and Beno{\^i}t Latr{\'e} and Bart Braem and Michael Peeters and Marijke De Soete and Peter De Cleyn and Bart Preneel and Ingrid Moerman and Chris Blondia},
  title = {A Secure Cross-layer Protocol for Multi-hop Wireless Body Area Networks},
  booktitle = {Ad-hoc, Mobile and Wireless Networks},
  publisher = {Springer Berlin / Heidelberg},
  issn = {0302-9743 (Print) 1611-3349 (Online)},
  isbn = {978-3-540-85208-7},
  abstract = {The development of Wireless Body Area Networks (WBANs) for wireless sensing and monitoring of a persons vital functions, is an enabler in providing better personal health care whilst enhancing the quality of life. A critical factor in the acceptance of WBANs is providing appropriate security and privacy protection of the wireless communication. This paper first describes a general health care platform and pinpoints the security challenges and requirements. Further it proposes and analyzes the CICADA-S protocol, a secure cross-layer protocol for WBANs. It is an extension of CICADA, which is a cross-layer protocol that handles both medium access and the routing of data in WBANs. The CICADA-S protocol is the first integrated solution that copes with threats that occur in this mobile medical monitoring scenario. It is shown that the integration of key management and secure, privacy preserving communication techniques within the CICADA-S protocol has low impact on the power consumption and throughput.},
  volume = {5198},
  series = {Lecture Notes in Computer Science},
  year = {2008},
  month = {SEP},
  pages = {94--107},
  location = {Sophia Antipolis, France},
  subject_collection = {Computer Science},
  doi = {10.1007/978-3-540-85209-4_8},
  URL = {content/publications/2008/bbraem08securewbanprotocol.pdf}
  }
  
  Abstract:
  The development of Wireless Body Area Networks (WBANs) for wireless sensing and monitoring of a persons vital functions, is an enabler in providing better personal health care whilst enhancing the quality of life. A critical factor in the acceptance of WBANs is providing appropriate security and privacy protection of the wireless communication. This paper first describes a general health care platform and pinpoints the security challenges and requirements. Further it proposes and analyzes the CICADA-S protocol, a secure cross-layer protocol for WBANs. It is an extension of CICADA, which is a cross-layer protocol that handles both medium access and the routing of data in WBANs. The CICADA-S protocol is the first integrated solution that copes with threats that occur in this mobile medical monitoring scenario. It is shown that the integration of key management and secure, privacy preserving communication techniques within the CICADA-S protocol has low impact on the power consumption and throughput.

• FCFS tree algorithms with interference cancellation and single signal memory requirements
  B. Van Houdt & G.T. Peeters
  Proceedings of the International Workshop on Multiple Access Communications (MACOM2008), 2008.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @InProceedings{gpeeters2008macom,
  author = {B. Van Houdt, G.T. Peeters},
  title = {FCFS tree algorithms with interference cancellation and single signal memory requirements},
  booktitle = {Proceedings of the International Workshop on Multiple Access Communications (MACOM2008)},
  year = {2008},
  URL = {content/publications/2008/gpeeters08macom.pdf},
  abstract = {Tree algorithms are a well studied class of collision resolution algorithms for solving multiple access control problems. Signal interference cancellation, which allows one to
  recover additional information from otherwise lost collision signals, has recently been combined with tree algorithms, providing substantially higher maximum stable throughputs (MST).
  We propose two novel First-Come-First-Served tree algorithms, the operation of which is similar to the well-known 0.4871 FCFS tree algorithm, that exploit interference cancellation and derive their MST.
  Both these algorithms are also designed such that, at all times, at most one signal must be stored.
  }
  }
  
  Abstract:
  Tree algorithms are a well studied class of collision resolution algorithms for solving multiple access control problems. Signal interference cancellation, which allows one to additional information from otherwise lost collision signals, has recently been combined with tree algorithms, providing substantially higher maximum stable throughputs (MST). propose two novel First-Come-First-Served tree algorithms, the operation of which is similar to the well-known 0.4871 FCFS tree algorithm, that exploit interference cancellation and derive their MST. these algorithms are also designed such that, at all times, at most one signal must be stored.

• A Hybrid realtime component model for reconfigurable embedded systems
  N. Gui, V. De Florio, H. Sun & C. Blondia
  Proceedings of the 23rd Annual ACM Symposium on Applied Computing (SAC2008), ACM, 2008.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{GDSB08a,
  author = {N. Gui, V. De Florio, H. Sun and C. Blondia},
  title = {A Hybrid realtime component model for reconfigurable embedded systems},
  booktitle = {Proceedings of the 23rd Annual ACM Symposium on Applied Computing (SAC2008)},
  address = {Fortaleza, Ceará, Brazil},
  year = {2008},
  month = {March},
  day = {16--20},
  publisher = {ACM},
  url = {content/publications/2008/sac08.pdf}
  }
  
  Abstract:
  Not available

• Adaptive Data Integrity through Dynamically Redundant Data Structures
  V. De Florio & C. Blondia
  Proceedings of the Third International Conference on Availability, Reliability and Security - ARES 2008, 2008.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{DB08b,
  author = {V. De Florio and C. Blondia},
  title = {Adaptive Data Integrity through Dynamically Redundant Data Structures},
  booktitle = {Proceedings of the Third International Conference on Availability, Reliability and Security - ARES 2008},
  address = {Barcelona, Spain},
  year = {2008},
  url = {http://euterpe.cmi.ua.ac.be/~vincenz/ares08.pdf},
  month = {March},
  day = {4--7},
  }
  
  Abstract:
  Not available

• QBD Markov chains on binomial-like trees and its application to multilevel feedback queues
  B. Van Houdt, J. Van Velthoven & C. Blondia
  Annals of Operations Research, Vol. 160, pp. 3-18, 2008.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @ARTICLE{vanvelthoven6,
  author={B. Van Houdt and J. Van Velthoven and C. Blondia},
  title={QBD Markov chains on binomial-like trees and its application to multilevel feedback queues},
  journal = {Annals of Operations Research},
  volume={160},
  pages = {3-18},
  year = {2008},
  URL = {content/publications/2008/JVV_MAM6.pdf},
  abstract = {A matrix analytic paradigm, termed Quasi-Birth-Death Markov chains on binomial-like trees,
  is introduced and a quadratically converging algorithm to assess its steady state is presented.
  In a bivariate Markov chain (X_t,N_t), the values of the variable X_t
  are nodes of a binomial-like tree of order d, where the i-th child has i children of its own. We demonstrate that it suffices to
  solve d quadratic matrix equations to yield the steady state vector, the form
  of which is matrix geometric.
  We apply this framework to analyze the multilevel
  feedback scheduling discipline, which forms an essential part in contemporary operating systems.}
  
  Abstract:
  A matrix analytic paradigm, termed Quasi-Birth-Death Markov chains on binomial-like trees, introduced and a quadratically converging algorithm to assess its steady state is presented. a bivariate Markov chain (X_t,N_t), the values of the variable X_t nodes of a binomial-like tree of order d, where the i-th child has i children of its own. We demonstrate that it suffices to d quadratic matrix equations to yield the steady state vector, the form which is matrix geometric. apply this framework to analyze the multilevel scheduling discipline, which forms an essential part in contemporary operating systems.

• A Survey of Linguistic Structures for Application-level Fault-Tolerance
  Vincenzo De Florio & Chris Blondia
  ACM Computing Surveys, Vol. 40, No. 2, 2008.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @ARTICLE{DeBl08a,
  author = {Vincenzo De Florio and Chris Blondia},
  title = {A Survey of Linguistic Structures for Application-level Fault-Tolerance},
  journal = {ACM Computing Surveys},
  volume = {40},
  number = {2},
  year = {2008},
  month = {April},
  burl = {http://euterpe.cmi.ua.ac.be/~vincenz/alft.pdf},
  url = {http://dl.acm.org/authorize?942886},
  abstract = {Structures for the expression of fault-tolerance provisions in application software comprise the central topic of this article. Structuring techniques answer questions as to how to incorporate fault tolerance in the application layer of a computer program and how to manage the fault-tolerant code. As such, they provide the means to control complexity, the latter being a relevant factor for the introduction of design faults. This fact and the ever-increasing complexity of today's distributed software justify the need for simple, coherent, and effective structures for the expression of fault-tolerance in the application software. In this text we first define a “base” of structural attributes with which application-level fault-tolerance structures can be qualitatively assessed and compared with each other and with respect to the aforementioned needs. This result is then used to provide an elaborated survey of the state-of-the-art of application-level fault-tolerance structures.}
  }
  
  Abstract:
  Structures for the expression of fault-tolerance provisions in application software comprise the central topic of this article. Structuring techniques answer questions as to how to incorporate fault tolerance in the application layer of a computer program and how to manage the fault-tolerant code. As such, they provide the means to control complexity, the latter being a relevant factor for the introduction of design faults. This fact and the ever-increasing complexity of today s distributed software justify the need for simple, coherent, and effective structures for the expression of fault-tolerance in the application software. In this text we first define a “base” of structural attributes with which application-level fault-tolerance structures can be qualitatively assessed and compared with each other and with respect to the aforementioned needs. This result is then used to provide an elaborated survey of the state-of-the-art of application-level fault-tolerance structures.

• Queues in DOCSIS cable modem networks
  J. Lambert, B. Van Houdt & C. Blondia
  Computers and Operations Research, Special Issue on Queues in Practice, Vol. 35, pp. 2482-2496, 2008.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @ARTICLE{CORQP051125b,
  author = {J. Lambert, B. Van Houdt and C. Blondia},
  title = {Queues in DOCSIS cable modem networks},
  booktitle = {Computers and Operations Research, Special Issue on Queues in Practice},
  year = {2008},
  volume = {35},
  pages = {2482--2496},
  URL = {content/publications/2008/CAOR1951LambertJoke2008.pdf},
  abstract = {In this paper we determine the optimal fraction of the uplink channel capacity that
  should be dedicated to the contention channel in a DOCSIS cable network in order to
  minimize its mean response time. For this purpose, we have developed an open queueing
  network with a non-standard form of blocking consisting of tens to hundreds of nodes.
  The network contains several types of customers that enter the network at various points
  according to a Markovian arrival process with marked customers. One of the main building
  blocks of the model exists in capturing the behavior of the conflict resolution algorithm
  by means of a single processor sharing queue. To assess the performance characteristics
  of this open queueing network we rely on an advanced decomposition technique that is
  specifically designed to deal with the Markovian nature of the arrival pattern. Several
  simulations are run to confirm the accuracy of the decomposition technique. We also
  explore the impact of a variety of systems parameters, e.g., the number of cable modems,
  the initial backoff window size, the correlation structure of the arrival process, the mean
  packet sizes, etc. , on the optimal fraction}
  }
  
  Abstract:
  In this paper we determine the optimal fraction of the uplink channel capacity that be dedicated to the contention channel in a DOCSIS cable network in order to its mean response time. For this purpose, we have developed an open queueing with a non-standard form of blocking consisting of tens to hundreds of nodes. network contains several types of customers that enter the network at various points to a Markovian arrival process with marked customers. One of the main building of the model exists in capturing the behavior of the conflict resolution algorithm means of a single processor sharing queue. To assess the performance characteristics this open queueing network we rely on an advanced decomposition technique that is designed to deal with the Markovian nature of the arrival pattern. Several are run to confirm the accuracy of the decomposition technique. We also the impact of a variety of systems parameters, e.g., the number of cable modems, initial backoff window size, the correlation structure of the arrival process, the mean sizes, etc. , on the optimal fraction

2007

• Service Matching in Online Community for Mutual Assisted Living
  Hong Sun, Vincenzo De Florio, Ning Gui & Chris Blondia
  Proceedings of the 3rd Int.l Conference on Signal-Image Technology & Internet based Systems (SITIS 2007), Shanghai, China, 2007.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{Sitis07,
  author = {Hong Sun, Vincenzo De Florio, Ning Gui, Chris Blondia},
  title = {Service Matching in Online Community for Mutual Assisted Living},
  booktitle = {Proceedings of the 3rd Int.l Conference on Signal-Image Technology & Internet based Systems (SITIS' 2007)},
  year = {2007},
  month = {December},
  day = {16--19},
  location = {Shanghai, China},
  URL = {content/publications/2007/Sitis07.pdf}
  }
  
  Abstract:
  Not available

• Comparison of Simulcast and Scalable Video Coding in Terms of the Required Capacity in an IPTV Network
  Z. Avramova, D. De Vleeschauwer, K. Spaey, S. Wittevrongel, H. Bruneel & C. Blondia
  Proceedings of 16th International Packet Video Workshop (PV2007), Lausanne, Switzerland, 2007.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{PV2007,
  author = {Z. Avramova and D. De Vleeschauwer and K. Spaey and S. Wittevrongel and H. Bruneel and C. Blondia},
  title = {Comparison of Simulcast and Scalable Video Coding in Terms of the Required Capacity in an IPTV Network},
  booktitle = {Proceedings of 16th International Packet Video Workshop (PV2007)},
  year = {2007},
  month = nov,
  location = {Lausanne, Switzerland},
  URL = {content/publications/2007/15-1569053891.pdf}
  }
  
  Abstract:
  Not available

• Last-Backlogged First-Served Deficit Round Robin (LBFS-DRR) Packet Scheduling Algorithm
  Dessislava Nikolova & C. Blondia
  Proceedings of the 15th International Conference on Networks (ICON2007), Adelaide, Australia, 2007.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{ICON,
  author = {Dessislava Nikolova and C. Blondia},
  title = {Last-Backlogged First-Served Deficit Round Robin (LBFS-DRR) Packet Scheduling Algorithm},
  booktitle = {Proceedings of the 15th International Conference on Networks (ICON2007)},
  year = {2007},
  month = {NOV},
  location = {Adelaide, Australia},
  URL = {content/publications/2007/LBFS-DRR.pdf},
  abstract = {In this article we present a novel packet scheduling algorithm LBFS-DRR, which combines features from the Last-Come First-Served scheduling discipline and the Deficit Round Robin (DRR) algorithm. In comparison with DRR it provides lower average packet delay, while preserving the advantageous feature like O(1) complexity, fairness, bandwidth guarantee. The lower mean delay is realized by giving service in a round first to flows transmitting bellow their (weighted) fair share. The algorithm exploits the high variability in the typical user traffic pattern resulting in lower mean file transfer delay. }
  }
  
  Abstract:
  In this article we present a novel packet scheduling algorithm LBFS-DRR, which combines features from the Last-Come First-Served scheduling discipline and the Deficit Round Robin (DRR) algorithm. In comparison with DRR it provides lower average packet delay, while preserving the advantageous feature like O(1) complexity, fairness, bandwidth guarantee. The lower mean delay is realized by giving service in a round first to flows transmitting bellow their (weighted) fair share. The algorithm exploits the high variability in the typical user traffic pattern resulting in lower mean file transfer delay.

• Adaptive REACT Protocol for Emergency Applications in Vehicular Networks
  Erwin Van de Velde & Chris Blondia
  Proc. of First IEEE LCN Workshop On User MObility and VEhicular Networks (ON-MOVE), Dublin, Ireland, 2007.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{VdVelde07,
  author = { Erwin Van de Velde and Chris Blondia},
  title = {Adaptive REACT Protocol for Emergency Applications in Vehicular Networks},
  booktitle = {Proc. of First IEEE LCN Workshop On User MObility and VEhicular Networks (ON-MOVE)},
  year = {2007},
  month = {October},
  location = {Dublin, Ireland},
  URL = {content/publications/2007/adaptive_react.pdf},
  abstract = {Vehicular communication is gaining more and more interest from big consortia and companies in the car industry. Wireless communication in a vehicular environment creates unique opportunities but poses also its own challenges. Therefore we proposed in previous work a new routing protocol, REACT, which uses geographical information and is able to react to a fast changing environment. In this paper, we will look at a few optimizations for this protocol in order to make it more adaptive to the current network conditions. As vehicles move very fast, link breaks occur more often. We attempt to predict this behavior, trying to use a link as long as possible but not longer than it really exists. Another important part of the REACT protocol consists of beaconing as means of exchanging position information with neighbors. The interval between two consecutive beacons is an important parameter in determining the end-to-end delay and we propose an algorithm that adapts this parameter in order to speed up neighbor discovery without generating too much beaconing overhead. The two optimizations were implemented and tested in a simulator and the results show a performance amelioration in the end-to-end delay in scenarios with sparse and dense road traffic.}
  }
  
  Abstract:
  Vehicular communication is gaining more and more interest from big consortia and companies in the car industry. Wireless communication in a vehicular environment creates unique opportunities but poses also its own challenges. Therefore we proposed in previous work a new routing protocol, REACT, which uses geographical information and is able to react to a fast changing environment. In this paper, we will look at a few optimizations for this protocol in order to make it more adaptive to the current network conditions. As vehicles move very fast, link breaks occur more often. We attempt to predict this behavior, trying to use a link as long as possible but not longer than it really exists. Another important part of the REACT protocol consists of beaconing as means of exchanging position information with neighbors. The interval between two consecutive beacons is an important parameter in determining the end-to-end delay and we propose an algorithm that adapts this parameter in order to speed up neighbor discovery without generating too much beaconing overhead. The two optimizations were implemented and tested in a simulator and the results show a performance amelioration in the end-to-end delay in scenarios with sparse and dense road traffic.

• Controlling the contention-based medium access in mobile ad hoc networks
  Sylwia Romaszko & Chris Blondia
  Accepted at the International Conference on the Latest Advances in Networks (ICLAN 2007), Paris, France, December 2007, 2007.
  BibTeX | Abstract
  
  Bibtex:
  @INPROCEEDINGS{sromaszko07iclanpar,
  author = {Sylwia Romaszko and Chris Blondia},
  title = {Controlling the contention-based medium access in mobile ad hoc networks},
  booktitle = {Accepted at the International Conference on the Latest Advances in Networks (ICLAN'2007) },
  year = {2007},
  location = {Paris, France, December 2007},
  abstract = {We propose a novel MAC protocol for wireless mobile ad hoc LANs. The first part of our protocol takes care of the adjustment of the lower and upper bound of the Contention Window interval considering the number of 1-hop active neighbors, the number of retransmission attempts and the energy level of the battery. The second part of our protocol is involved in the resetting Contention Window (CW) issue regarding the network load, the channel conditions and mobility. The protocol provides solutions to the CW resetting and the static adoption of the lower and upper bounds. Our protocol clearly outperforms the 802.11 DCF in terms of throughput, lifetime and delay performance. }
  }
  
  Abstract:
  We propose a novel MAC protocol for wireless mobile ad hoc LANs. The first part of our protocol takes care of the adjustment of the lower and upper bound of the Contention Window interval considering the number of 1-hop active neighbors, the number of retransmission attempts and the energy level of the battery. The second part of our protocol is involved in the resetting Contention Window (CW) issue regarding the network load, the channel conditions and mobility. The protocol provides solutions to the CW resetting and the static adoption of the lower and upper bounds. Our protocol clearly outperforms the 802.11 DCF in terms of throughput, lifetime and delay performance.

• Distributed On Demand Channel Selection in Multi Channel, Multi Interface Wireless Mesh Networks
  S. Bouckaert, N. Letor, C. Blondia, I. Moerman & P. Demeester
  Proc. Globecom 2007, 2007.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @ARTICLE{bouck07a,
  author = {S. Bouckaert, N. Letor, C. Blondia, I. Moerman and P. Demeester},
  title = {Distributed On Demand Channel Selection in Multi Channel, Multi Interface Wireless Mesh Networks},
  abstract = {In this paper we present a protocol performing on demand distributed channel selection in multi channel, multi interface wireless mesh networks, based on the exchange of control messages. The link based channel reservation happens almost instantly when data traffic is sent through the network, and does not require long-term traffic profiles or measurements.
  The protocol is both simulated and implemented using the IEEE 802.11b/g protocol. We show that in a raster topology, the protocol successfully optimizes the local spectrum usage at 87% of the nodes, and that globally, an equal amount of links is allocated to each of the channels used for the transport of data packets.},
  booktitle = {Proc. Globecom 2007},
  year = {2007},
  month = {November},
  URL = {content/publications/2007/bouckaert07fresme.pdf}
  }
  
  Abstract:
  In this paper we present a protocol performing on demand distributed channel selection in multi channel, multi interface wireless mesh networks, based on the exchange of control messages. The link based channel reservation happens almost instantly when data traffic is sent through the network, and does not require long-term traffic profiles or measurements. The protocol is both simulated and implemented using the IEEE 802.11b/g protocol. We show that in a raster topology, the protocol successfully optimizes the local spectrum usage at 87% of the nodes, and that globally, an equal amount of links is allocated to each of the channels used for the transport of data packets.

• Connection Management over an Ethernet based Wireless Mesh Network
  W. Vandenberghe, K. Lamont, I. Moerman, P. Demeester, J. Avonts & C. Blondia
  Accepted at IEEE Conference on Wireless Rural and Emergency Communications, 2007.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @ARTICLE{total,
  author = {W. Vandenberghe, K. Lamont, I. Moerman, P. Demeester, J. Avonts, C. Blondia},
  title = {Connection Management over an Ethernet based Wireless Mesh Network},
  booktitle = {Accepted at IEEE Conference on Wireless Rural and Emergency Communications},
  abstract={In this paper we discuss the Wireless Mesh Network
  developed in the scope of the IBBT Wireless Building Automation
  project. This WMN is designed as a high datarate wireless
  backbone interconnection between the other wireless networks
  used in the WBA architecture. We will demonstrate that switched
  Ethernet is a technology that, with minimal effort, can be used
  as a base for WMNs. We will also talk about the distributed
  optimizations that were implemented and combined to boost
  network performance. We will introduce the novel concept
  of Connection Management, introducing network engineering
  techniques in the Wireless Mesh domain for the first time. Finally,
  the testbed used for deployment will be explained, and some
  results of tests performed in a real-life environment will we
  discussed.
  },
  year = {2007},
  month = {AUG},
  URL = {content/publications/2007/Connection_Management_wba.pdf}
  }
  
  Abstract:
  In this paper we discuss the Wireless Mesh Network in the scope of the IBBT Wireless Building Automation This WMN is designed as a high datarate wireless interconnection between the other wireless networks in the WBA architecture. We will demonstrate that switched is a technology that, with minimal effort, can be used a base for WMNs. We will also talk about the distributed that were implemented and combined to boost performance. We will introduce the novel concept Connection Management, introducing network engineering in the Wireless Mesh domain for the first time. Finally, testbed used for deployment will be explained, and some of tests performed in a real-life environment will we

• A policy iteration algorithm for Markov decision processes skip-free in one direction
  J. Lambert, B. Van Houdt & C. Blondia
  Proceedings of the International Workshop on Tools for solving Structured Markov Chains (SMCtools 2007), Nantes, France, 2007.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{SMCtools 2007,
  author={J. Lambert and B. Van Houdt and C. Blondia},
  title={A policy iteration algorithm for Markov decision processes skip-free in one direction},
  booktitle = {Proceedings of the International Workshop on Tools for solving Structured Markov Chains (SMCtools 2007), Nantes, France},
  year = {2007},
  URL = {content/publications/2007/LambertSMCTools2007.pdf},
  abstract = {In this paper we present a new algorithm for policy iteration for Markov decision processes (MDP) skip-free in one direction. This algorithm, which is based on matrix analytic methods, is in the same spirit as the algorithm of White (Stochastic Models, 21:785-797, 2005) which was limited to matrices that are skip-free in both directions.
  Optimization problems that can be solved using Markov decision processes arise in the domain of optical buffers, when trying to improve loss rates of fibre delay line (FDL) buffers. Based on the analysis of such an FDL buffer we present a comparative study between the different techniques available to solve an MDP. The results illustrate that the exploitation of the structure of the transition matrices places us in a position to deal with larger systems, while reducing the computation times.}
  }
  
  Abstract:
  In this paper we present a new algorithm for policy iteration for Markov decision processes (MDP) skip-free in one direction. This algorithm, which is based on matrix analytic methods, is in the same spirit as the algorithm of White (Stochastic Models, 21:785-797, 2005) which was limited to matrices that are skip-free in both directions. problems that can be solved using Markov decision processes arise in the domain of optical buffers, when trying to improve loss rates of fibre delay line (FDL) buffers. Based on the analysis of such an FDL buffer we present a comparative study between the different techniques available to solve an MDP. The results illustrate that the exploitation of the structure of the transition matrices places us in a position to deal with larger systems, while reducing the computation times.

• A wireless network for emergency services: a multi-channel ad-hoc approach
  J. Bergs, D. Naudts, C. Blondia, N. Van den Wijngaert, I. Moerman & P. Demeester
  Proc. The Wireless Rural and Emergency Communications Conference, Rome, Italy, 2007.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{jbergs07OTGCI,
  author = {J. Bergs and D. Naudts and C. Blondia and N. Van den Wijngaert and I. Moerman and P. Demeester},
  title = {A wireless network for emergency services: a multi-channel ad-hoc approach},
  booktitle = {Proc. The Wireless Rural and Emergency Communications Conference},
  year = {2007},
  month = {OCT},
  location = {Rome, Italy},
  URL = {content/publications/2007/jbergs07AWirelessNetworkforEmergencyServices.pdf},
  abstract = {Deploying ad-hoc wireless mesh networks for emergency services is a popular topic. One of the main challenges in these networks is to overcome the performance hit due to the interference that is inherent to 802.11 wireless technology. A possible solution is to use multiple interfaces and multiple channels throughout the network in order to minimize this interference. In this paper, we will describe the approach used in a project focused on deploying an emergency ad-hoc network.}
  }
  
  Abstract:
  Deploying ad-hoc wireless mesh networks for emergency services is a popular topic. One of the main challenges in these networks is to overcome the performance hit due to the interference that is inherent to 802.11 wireless technology. A possible solution is to use multiple interfaces and multiple channels throughout the network in order to minimize this interference. In this paper, we will describe the approach used in a project focused on deploying an emergency ad-hoc network.

• Enabling cross layer design: adding the MadWifi extensions to Nsclick
  N. Letor & P. De Cleyn & C. Blondia
  Proc. First International Workshop on Network Simulation Tools 2007 in conjunction with Valuetools 2007, 2007.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @ARTICLE{nsmadwifi,
  author = {N. Letor, P. De Cleyn & C. Blondia},
  title = {Enabling cross layer design: adding the MadWifi extensions to Nsclick},
  booktitle = {Proc. First International Workshop on Network Simulation Tools 2007 in conjunction with Valuetools 2007},
  abstract={Simulations have always been a very useful and powerful tool to study and develop networking protocols. ns-2 is one of the most commonly used open-source network simulators and many protocols have been evaluated with this tool. In order to bridge the gap between simulation and implementation on a real testbed, Nsclick was developed. Nsclick makes it possible to entirely reuse code between the ns-2 simulator and a testbed, based on the Click Modular Router. In the quest for high performance wireless networks, researchers have found that the layered architecture networks did not perform well enough. Therefore they focused their research on cross layer design techniques. Although using Click and the Mad-Wifi driver gives us many possibilities to design and evaluate cross layer optimizations in a testbed set up, the Nsclick platform does not support these extensions. In this paper we will introduce an extension to ns-2 which overcomes these shortcomings of the Nsclick platform. This extension makes the wireless features of the Click Modular Router available in Nsclick platform, eliminating the differences between the ns-2 simulator, within the Nsclick platform, and a real world set up.},
  year = {2007},
  month = {October},
  URL = {content/publications/2007/nletor07nsmadwifi.pdf}
  }
  
  Abstract:
  Simulations have always been a very useful and powerful tool to study and develop networking protocols. ns-2 is one of the most commonly used open-source network simulators and many protocols have been evaluated with this tool. In order to bridge the gap between simulation and implementation on a real testbed, Nsclick was developed. Nsclick makes it possible to entirely reuse code between the ns-2 simulator and a testbed, based on the Click Modular Router. In the quest for high performance wireless networks, researchers have found that the layered architecture networks did not perform well enough. Therefore they focused their research on cross layer design techniques. Although using Click and the Mad-Wifi driver gives us many possibilities to design and evaluate cross layer optimizations in a testbed set up, the Nsclick platform does not support these extensions. In this paper we will introduce an extension to ns-2 which overcomes these shortcomings of the Nsclick platform. This extension makes the wireless features of the Click Modular Router available in Nsclick platform, eliminating the differences between the ns-2 simulator, within the Nsclick platform, and a real world set up.

• Optimal batch scheduling in DVB-S2 satellite networks
  G. T. Peeters, B. Van Houdt & C. Blondia
  IEEE Global Telecommunications Conference, 2007. GLOBECOM 07, pp. 4607-4612, 2007.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{gpeeters2007globecom,
  author={G. T. Peeters and B. Van Houdt and C. Blondia},
  title={Optimal batch scheduling in DVB-S2 satellite networks},
  booktitle={IEEE Global Telecommunications Conference, 2007. GLOBECOM '07},
  year={2007},
  pages={4607-4612},
  URL = {content/publications/2007/gpeeters2007globecom.pdf},
  abstract = {In this paper we present a new theoretical model to assess the performance of a class of batch scheduling orders in a forward DVB-S2 satellite link. The scheduling order in a DVB-S2 link will determine the order in which IP packets are transmitted to the receivers and thus determines the amount of required padding and sub-optimal transmissions. The validity of the model is investigated by various simulation runs which show a very close agreement with the theoretical model.
  Using this model we also identify the optimal scheduling order within this class of orders, given that some mild and realistic conditions on the modulation and
  coding schemes apply.}
  
  Abstract:
  In this paper we present a new theoretical model to assess the performance of a class of batch scheduling orders in a forward DVB-S2 satellite link. The scheduling order in a DVB-S2 link will determine the order in which IP packets are transmitted to the receivers and thus determines the amount of required padding and sub-optimal transmissions. The validity of the model is investigated by various simulation runs which show a very close agreement with the theoretical model. this model we also identify the optimal scheduling order within this class of orders, given that some mild and realistic conditions on the modulation and schemes apply.

• Distributed Channel Allocation In Multi-Radio Wireless Mesh Networks
  J. Avonts & N. Van den Wijngaert & C. Blondia
  Accepted at The First International Workshop on Wireless Mesh and Ad Hoc Networks in conjunction with ICCCN 2007, 2007.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @ARTICLE{total,
  author = {J. Avonts, N. Van den Wijngaert & C. Blondia},
  title = {Distributed Channel Allocation In Multi-Radio Wireless Mesh Networks},
  booktitle = {Accepted at The First International Workshop on Wireless Mesh and Ad Hoc Networks in conjunction with ICCCN 2007},
  abstract={One of the major advantages of wireless communication over wired is the flexibility when creating links between
  nodes. But this comes at a price as influences from outside the
  mesh network can distort communication between the nodes
  and even the nodes themselves interfere with each other. By
  carefully selecting channels where each link transmits data on,
  the interference can be minimized causing the throughput and
  end-to-end delay to be improved. We propose an algorithm that
  only uses locally distributed information to find the best channel
  selection for each link. The algorithm is independent of the
  used routing algorithm and scales well. Using simulations we
  will demonstrate scalability, convergence and finding an optimal
  solution.},
  year = {2007},
  month = {MAY},
  URL = {content/publications/2007/200609CA_WiMAN2007.pdf}
  }
  
  Abstract:
  One of the major advantages of wireless communication over wired is the flexibility when creating links between But this comes at a price as influences from outside the network can distort communication between the nodes even the nodes themselves interfere with each other. By selecting channels where each link transmits data on, interference can be minimized causing the throughput and delay to be improved. We propose an algorithm that uses locally distributed information to find the best channel for each link. The algorithm is independent of the routing algorithm and scales well. Using simulations we demonstrate scalability, convergence and finding an optimal solution.

• A System Structure for Adaptive Services
  V. De Florio
  presented at KU.Leuven/DistriNet/AgentWise, Leuven, Belgium, 2007.
  BibTeX | PDF Available
  
  Bibtex:
  @Misc{DeFl07b,
  author = {V. De Florio},
  title = {A System Structure for Adaptive Services},
  booktitle = {presented at KU.Leuven/DistriNet/AgentWise},
  howpublished= {http://www.win.ua.ac.be/~vincenz/distritalk20070704.pdf},
  url = {http://www.win.ua.ac.be/~vincenz/distritalk20070704.pdf},
  location = {Leuven, Belgium},
  year = {2007},
  month = {July},
  day = {4},
  }
  
  Abstract:
  Not available

• A wireless mesh monitoring and planning tool for emergency services
  D. Naudts, S. Bouckaert, J. Bergs, A. Schoutteet, C. Blondia, I. Moerman & P. Demeester
  Proc. The 5th IEEE Workshop on End-to-End Monitoring Techniques and Services, Munich, Germany, 2007.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{jbergs07OTGCI,
  author = {D. Naudts and S. Bouckaert and J. Bergs and A. Schoutteet and C. Blondia and I. Moerman and P. Demeester},
  title = {A wireless mesh monitoring and planning tool for emergency services},
  booktitle = {Proc. The 5th IEEE Workshop on End-to-End Monitoring Techniques and Services},
  year = {2007},
  month = {MAY},
  location = {Munich, Germany},
  URL = {content/publications/2007/jbergs07OTGCI.pdf},
  abstract = {During a crisis situation, it is essential for emergency services to have a reliable communication network. Because one cannot trust on existing infrastructure, wireless mesh technology can be a good networking mechanism to provide high broadband communication while performing rescue operations. In this paper, we will describe the concept and implementation of a monitoring and planning tool that can assist an intervention team in deploying the network and providing a real-time overview of the status of the network. To minimize overhead on the network, we use the packet pair probing technique for the estimation of the link capacity. The information is disseminated throughout the network to estimate end-to-end throughput. Our distributed monitoring technique is based on a layer 3 approach, which is transparent to underlying layers. To assist the intervention team in determining the best location for adding new nodes, our planning tool will continuously monitor signal strength in the environment. The applicability of the system is proven by experiment in a real testing environment.}
  }
  
  Abstract:
  During a crisis situation, it is essential for emergency services to have a reliable communication network. Because one cannot trust on existing infrastructure, wireless mesh technology can be a good networking mechanism to provide high broadband communication while performing rescue operations. In this paper, we will describe the concept and implementation of a monitoring and planning tool that can assist an intervention team in deploying the network and providing a real-time overview of the status of the network. To minimize overhead on the network, we use the packet pair probing technique for the estimation of the link capacity. The information is disseminated throughout the network to estimate end-to-end throughput. Our distributed monitoring technique is based on a layer 3 approach, which is transparent to underlying layers. To assist the intervention team in determining the best location for adding new nodes, our planning tool will continuously monitor signal strength in the environment. The applicability of the system is proven by experiment in a real testing environment.

• A multiaccess tree algorithm with free access, interference cancellation and single signal memory requirements
  G. T. Peeters, B. Van Houdt & C. Blondia
  Perform. Eval., Vol. 64, No. 9-12, pp. 1041-1052, Elsevier Science Publishers B. V., 2007.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @article{gpeeters2007sic,
  author = {G. T. Peeters and B. Van Houdt and C. Blondia},
  title = {A multiaccess tree algorithm with free access, interference cancellation and single signal memory requirements},
  journal = {Perform. Eval.},
  volume = {64},
  number = {9-12},
  year = {2007},
  issn = {0166-5316},
  pages = {1041--1052},
  doi = {http://dx.doi.org/10.1016/j.peva.2007.06.009},
  publisher = {Elsevier Science Publishers B. V.},
  address = {Amsterdam, The Netherlands, The Netherlands},
  URL = {content/publications/2007/gpeeters2007sic.pdf},
  abstract = {Tree algorithms are a well studied class of collision resolution algorithms for solving multiple access control problems. Successive interference cancellation, which allows one to
  recover additional information from otherwise lost collision signals, has recently been combined with tree algorithms with blocked access (Yu and Giannakis, Infocom 2005, pp. 1908-1916), providing a substantially higher maximum stable throughput (MST): 0.693 for Poisson arrivals, given an infinite number of memory locations for storing signals. We propose a novel tree algorithm for a similar problem, but with two relaxed model assumptions: free access is supported and a single signal memory location suffices. A study of the maximal stable throughput of this algorithm is provided using matrix analytic methods; as a result, an MST of 0.5698 for Poisson arrivals is achieved. Our methodology also allows us to investigate the MST
  when the multiple access channel is subject to Markovian arrival processes.}
  }
  
  Abstract:
  Tree algorithms are a well studied class of collision resolution algorithms for solving multiple access control problems. Successive interference cancellation, which allows one to additional information from otherwise lost collision signals, has recently been combined with tree algorithms with blocked access (Yu and Giannakis, Infocom 2005, pp. 1908-1916), providing a substantially higher maximum stable throughput (MST): 0.693 for Poisson arrivals, given an infinite number of memory locations for storing signals. We propose a novel tree algorithm for a similar problem, but with two relaxed model assumptions: free access is supported and a single signal memory location suffices. A study of the maximal stable throughput of this algorithm is provided using matrix analytic methods; as a result, an MST of 0.5698 for Poisson arrivals is achieved. Our methodology also allows us to investigate the MST the multiple access channel is subject to Markovian arrival processes.

• Simultaneous Transient Analysis of QBD Markov Chains for all Initial Configurations using a Level Based Recursion
  J. Van Velthoven, B. Van Houdt & C. Blondia
  Proceedings of QEST 2007, Edinburgh (UK), IEEE Computer Society, pp. 79-88, 2007.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{vanvelthoven5,
  author={J. Van Velthoven and B. Van Houdt and C. Blondia},
  title={Simultaneous Transient Analysis of QBD Markov Chains for all Initial Configurations using a Level Based Recursion},
  booktitle = {Proceedings of QEST 2007, Edinburgh (UK), IEEE Computer Society},
  pages={79--88}
  year = {2007},
  month = {SEP},
  URL = {content/publications/2007/JVV_QEST07.pdf},
  abstract = {A new algorithm to assess transient performance measures for every possible initial configuration of a Quasi-Birth-and-Death (QBD) Markov chain is introduced. We make use of the framework termed QBDs with marked time epochs that transforms the transient problem into a stationary one by applying a discrete Erlangization and constructing a reset Markov chain. To avoid the need to repeat all computations for each initial configuration, we propose a level based recursive algorithm that uses intermediate
  results obtained for initial states belonging to levels 0,...,r-1 to compute the transient measure when the initial state is part of level r. Also, the computations for all states belonging to
  level r are performed simultaneously. A key property of our approach lies in the exploitation
  of the internal structure of the block matrices involved, avoiding any need to store large
  matrices. A flexible Matlab implementation of the proposed algorithm is available online.}
  
  Abstract:
  A new algorithm to assess transient performance measures for every possible initial configuration of a Quasi-Birth-and-Death (QBD) Markov chain is introduced. We make use of the framework termed QBDs with marked time epochs that transforms the transient problem into a stationary one by applying a discrete Erlangization and constructing a reset Markov chain. To avoid the need to repeat all computations for each initial configuration, we propose a level based recursive algorithm that uses intermediate obtained for initial states belonging to levels 0,...,r-1 to compute the transient measure when the initial state is part of level r. Also, the computations for all states belonging to r are performed simultaneously. A key property of our approach lies in the exploitation the internal structure of the block matrices involved, avoiding any need to store large A flexible Matlab implementation of the proposed algorithm is available online.

• The Need for Cooperation and Relaying in Short-Range High Path Loss Sensor Networks
  B. Braem, B. Latré, I. Moerman, C. Blondia, E. Reusens, W. Joseph, L. Martens & P. Demeester
  Sensor Technologies and Applications, 2007. SensorComm 2007. International Conference on, Valencia, Spain, pp. 566-571, 2007.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{bbraem07needcooperationrelaying,
  author = {B. Braem and B. Latr{\'e} and I. Moerman and C. Blondia and E. Reusens and W. Joseph and L. Martens and P. Demeester},
  title = {The Need for Cooperation and Relaying in Short-Range High
  Path Loss Sensor Networks},
  booktitle = {Sensor Technologies and Applications, 2007. SensorComm 2007. International Conference on},
  year = {2007},
  month = {OCT},
  location = {Valencia, Spain},
  pages = {566-571},
  URL = {content/publications/2007/bbraem07needcooperationrelaying.pdf},
  abstract = {This paper focuses on the energy efficiency of communication in small-scale sensor networks experiencing high path loss. In particular, a sensor network on the human body or BASN is considered. The energy consumption or network lifetime of a single-hop network and a multi-hop network are compared. We derive a propagation model and a radio model for communication along the human body. Using these models, energy efficiency was studied analytically for a line and a tree topology. Calculations show that single-hop communication is inefficient, especially for nodes far away from the sink. There however, multi-hop proves to be more efficient but closer to the sink hotspots arise. Based on these findings, we propose to exploit the performance difference by either introducing extra nodes in the network, i.e. dedicated relay devices, or by using a cooperative approach or by a combination of both. We show that these solutions increase the network lifetime significantly.},
  }
  
  Abstract:
  This paper focuses on the energy efficiency of communication in small-scale sensor networks experiencing high path loss. In particular, a sensor network on the human body or BASN is considered. The energy consumption or network lifetime of a single-hop network and a multi-hop network are compared. We derive a propagation model and a radio model for communication along the human body. Using these models, energy efficiency was studied analytically for a line and a tree topology. Calculations show that single-hop communication is inefficient, especially for nodes far away from the sink. There however, multi-hop proves to be more efficient but closer to the sink hotspots arise. Based on these findings, we propose to exploit the performance difference by either introducing extra nodes in the network, i.e. dedicated relay devices, or by using a cooperative approach or by a combination of both. We show that these solutions increase the network lifetime significantly.,

• QoS-enabled internet-on-train network architecture: interworking by MMP-SCTP versus MIP
  Daan Pareit, Nele Gheysens, Tom Van Leeuwen, Ingrid Moerman, Walter Van Brussel, Ines Clenjans, Wim Torfs, Peter De Cleyn & Chris Blondia
  Accepted at the 7th International Conference on ITS Telecommunications, Sophia Antipolis,France, 2007.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{torfsdecleyn07,
  author = {Daan Pareit, Nele Gheysens, Tom Van Leeuwen, Ingrid Moerman, Walter Van Brussel, Ines Clenjans, Wim Torfs, Peter De Cleyn and Chris Blondia},
  title = {QoS-enabled internet-on-train network architecture: interworking by MMP-SCTP versus MIP},
  booktitle = {Accepted at the 7th International Conference on ITS Telecommunications},
  year = {2007},
  month = {JUL},
  location = {Sophia Antipolis,France},
  URL = {content/publications/2007/sctpvsmip.pdf},
  abstract = {Internet-on-the-train is a rising concept in the last few years. Several trials in different countries have proved the feasibility of offering Internet access to train commuters, but none of them combines broadband access, scalability, seamless handover and quality of service guarantees in one solution. In this paper, we propose a new architecture to satisfy these needs. Using real handover measurement data of several common broadband wireless technologies, we compare two possible inter-working mobility solutions: Mobile Multi-Path SCTP (MMP-SCTP) and Mobile IP (MIP). },
  }
  
  Abstract:
  Internet-on-the-train is a rising concept in the last few years. Several trials in different countries have proved the feasibility of offering Internet access to train commuters, but none of them combines broadband access, scalability, seamless handover and quality of service guarantees in one solution. In this paper, we propose a new architecture to satisfy these needs. Using real handover measurement data of several common broadband wireless technologies, we compare two possible inter-working mobility solutions: Mobile Multi-Path SCTP (MMP-SCTP) and Mobile IP (MIP). ,

• Global Adaptation Framework for Quality of Experience of Mobile Services
  H. Sun, V. De Florio, N. Gui & C. Blondia
  Proceedings of the 2007 IEEE Three-Rivers Workshop on Soft Computing in Industrial Applications, 2007.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{SDGB07b,
  author = {H. Sun, V. De Florio, N. Gui and C. Blondia},
  title = {Global Adaptation Framework for Quality of Experience of Mobile Services},
  booktitle = {Proceedings of the 2007 IEEE Three-Rivers Workshop on Soft Computing in Industrial Applications},
  address = {Passau, Germany},
  year = {2007},
  month = {August},
  day = {1--3},
  url = {content/publications/2007/glaf07.pdf}
  }
  
  Abstract:
  Not available

• A Low-delay Protocol for Multihop Wireless Body Area Networks
  B. Latré, B. Braem, I. Moerman, C. Blondia, E. Reusens, W. Joseph & P. Demeester
  MOBIQUITOUS 07: Proceedings of the 2007 Fourth Annual International Conference on Mobile and Ubiquitous Systems: Networking & Services (MobiQuitous), Philadelphia, Pennsylvania, USA, pp. 1-8, IEEE Computer Society, 2007.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{bbraem07cicada,
  author = {B. Latr{\'e} and B. Braem and I. Moerman and C. Blondia and E. Reusens and W. Joseph and P. Demeester},
  title = {A Low-delay Protocol for Multihop Wireless Body Area Networks},
  booktitle = {MOBIQUITOUS '07: Proceedings of the 2007 Fourth Annual International Conference on Mobile and Ubiquitous Systems: Networking & Services (MobiQuitous)},
  year = {2007},
  month = {AUG},
  location = {Philadelphia, Pennsylvania, USA},
  isbn = {978-1-4244-1024-8},
  pages = {1--8},
  doi = {http://dx.doi.org/10.1109/MOBIQ.2007.4451060},
  publisher = {IEEE Computer Society},
  address = {Washington, DC, USA},
  URL = {content/publications/2007/bbraem07cicada.pdf},
  abstract = {Wireless Body Area Networks (WBANs) form a new and interesting area in the world of remote health monitoring. An important concern in such networks is the communication between the sensors. This communication needs to be energy efficient and highly reliable while keeping delays low. Mobility also has to be supported as the nodes are positioned on different parts of the body that move with regard to each other. In this paper, we present a new cross-layer communication protocol for WBANs: CICADA or Cascading Information retrieval by Controlling Access with Distributed slot Assignment. The protocol sets up a network tree in a distributed manner. This tree structure is subsequently used to guarantee collision free access to the medium and to route data towards the sink. The paper analyzes CICADA and shows simulation results. The protocol offers low delay and good resilience to mobility. The energy usage is low as the nodes can sleep in slots where they are not transmitting or receiving.},
  }
  
  Abstract:
  Wireless Body Area Networks (WBANs) form a new and interesting area in the world of remote health monitoring. An important concern in such networks is the communication between the sensors. This communication needs to be energy efficient and highly reliable while keeping delays low. Mobility also has to be supported as the nodes are positioned on different parts of the body that move with regard to each other. In this paper, we present a new cross-layer communication protocol for WBANs: CICADA or Cascading Information retrieval by Controlling Access with Distributed slot Assignment. The protocol sets up a network tree in a distributed manner. This tree structure is subsequently used to guarantee collision free access to the medium and to route data towards the sink. The paper analyzes CICADA and shows simulation results. The protocol offers low delay and good resilience to mobility. The energy usage is low as the nodes can sleep in slots where they are not transmitting or receiving.,

• (NIAMac) Neighbor and Interference -Aware MAC Protocol for Wireless Ad Hoc Networks
  Sylwia Romaszko & Chris Blondia
  Proceedings of the 16th IST Mobile and Wireless Communications Summit, Budapest, Hungary, July 2007, 2007.
  BibTeX | Abstract
  
  Bibtex:
  @INPROCEEDINGS{sromaszko07istmwcs,
  author = {Sylwia Romaszko and Chris Blondia},
  title = {(NIAMac) Neighbor and Interference -Aware MAC Protocol for Wireless Ad Hoc Networks},
  booktitle = {Proceedings of the 16th IST Mobile and Wireless Communications Summit},
  year = {2007},
  location = {Budapest, Hungary, July 2007},
  abstract = {The IEEE 802.11 currently used as the WLAN standard, specifies the Distributed Coordination Function (DCF), which is based on CSMA/CA, where the Carrier Sense is a fundamental part of most wireless networking stacks in WLANs and WSNs. The DCF provides the Contention Window (CW) value which is doubled after each collision and reset to the minimum value after each successful packet transmission or dropped packet. The CW is reset to the minimum (CWmin) independently of the network load, but successful packet transmission does not mean that the contention level is dropped only that a convenient CW value has been chosen. In this paper, we propose a Neighbor and Interference -Aware MAC protocol (NIAMac), which takes into account the number of near and far neighbors and the channel condition probability while resetting the Contention Window value. The NIAMac protocol decreases the number of collisions significantly which leads to a better throughput and First and Last Node Died performance than the IEEE 802.11 DCF standard. }
  }
  
  Abstract:
  The IEEE 802.11 currently used as the WLAN standard, specifies the Distributed Coordination Function (DCF), which is based on CSMA/CA, where the Carrier Sense is a fundamental part of most wireless networking stacks in WLANs and WSNs. The DCF provides the Contention Window (CW) value which is doubled after each collision and reset to the minimum value after each successful packet transmission or dropped packet. The CW is reset to the minimum (CWmin) independently of the network load, but successful packet transmission does not mean that the contention level is dropped only that a convenient CW value has been chosen. In this paper, we propose a Neighbor and Interference -Aware MAC protocol (NIAMac), which takes into account the number of near and far neighbors and the channel condition probability while resetting the Contention Window value. The NIAMac protocol decreases the number of collisions significantly which leads to a better throughput and First and Last Node Died performance than the IEEE 802.11 DCF standard.

• Analysis of the Influence of Video-Aware Traffic Management on the Performance of the Dejittering Mechanism
  K. Spaey & C. Blondia
  Proceedings of 20th International Teletraffic Congress (ITC20 2007), Ottawa, Canada, Lecture Notes in Computer Science, Vol. 4516, pp. 30-41, Springer, 2007.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{ITC2007,
  author = {K. Spaey and C. Blondia},
  title = {Analysis of the Influence of Video-Aware Traffic Management on the Performance of the Dejittering Mechanism},
  booktitle = {Proceedings of 20th International Teletraffic Congress (ITC20 2007)},
  pages = {30--41},
  year = {2007},
  month = jun,
  location = {Ottawa, Canada},
  series = {Lecture Notes in Computer Science},
  volume = {4516},
  publisher = {Springer},
  URL = {content/publications/2007/spaey_ITC2007.pdf}
  }
  
  Abstract:
  Not available

• Teaching Resilient Computing in Antwerp: Report, Considerations, and Vision
  V. De Florio
  presented at the EWICS-ReSIST Joint Workshop on Teaching Resilient Computing, Erlangen, Germany, 2007.
  BibTeX | PDF Available
  
  Bibtex:
  @Misc{DeFl07a,
  author = {V. De Florio},
  title = {Teaching Resilient Computing in Antwerp: Report, Considerations, and Vision},
  booktitle = {presented at the EWICS-ReSIST Joint Workshop on Teaching Resilient Computing},
  howpublished= {http://resist.isti.cnr.it/JWTRC},
  url = {http://resist.isti.cnr.it/JWTRC},
  location = {Erlangen, Germany},
  year = {2007},
  month = {May},
  day = {2},
  }
  
  Abstract:
  Not available

• Adaptive Feedback-loop Control System for Inter-reality Management
  V. De Florio, J. van Vaerenbergh & C. Blondia
  Proceedings of the 2007 IEEE Three-Rivers Workshop on Soft Computing in Industrial Applications, 2007.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{DB07e,
  author = {V. De Florio, J. van Vaerenbergh and C. Blondia},
  title = {Adaptive Feedback-loop Control System for Inter-reality Management},
  booktitle = {Proceedings of the 2007 IEEE Three-Rivers Workshop on Soft Computing in Industrial Applications},
  address = {Passau, Germany},
  year = {2007},
  URL = {content/publications/2007/SMCia07.pdf},
  month = {August},
  day = {1--3},
  }
  
  Abstract:
  Not available

• Reflective and Refractive Variables: A Model for Effective and Maintainable Adaptive-and-Dependable Software
  V. De Florio & C. Blondia
  Proceedings of the 33rd Euromicro Conference on Software Engineering and Advanced Applications (SEEA 2007), Software Process and Product Improvement track (SPPI), Luebeck, Germany, IEEE Computer Society, 2007.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{DB07d,
  author = {V. De Florio and C. Blondia},
  title = {Reflective and Refractive Variables: A Model for Effective and Maintainable Adaptive-and-Dependable Software},
  booktitle = {Proceedings of the 33rd Euromicro Conference on Software Engineering and Advanced Applications (SEEA 2007), Software Process and Product Improvement track (SPPI)},
  location = {Luebeck, Germany},
  publisher = {IEEE Computer Society},
  year = {2007},
  URL = {content/publications/2007/SPPI07.pdf},
  month = {August},
  day = {27--31},
  }
  
  Abstract:
  Not available

• Adaptation as a New Requirement for Software Engineering
  V. De Florio & C. Blondia
  Proceedings of the First IEEE WoWMoM Workshop on Adaptive and DependAble Mission- and bUsiness-critical mobile Systems (ADAMUS 2007), Helsinki, Finland, 2007.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{DB07c,
  author = {V. De Florio and C. Blondia},
  title = {Adaptation as a New Requirement for Software Engineering},
  booktitle = {Proceedings of the First IEEE WoWMoM Workshop on Adaptive and DependAble Mission- and bUsiness-critical mobile Systems (ADAMUS 2007)},
  location = {Helsinki, Finland},
  year = {2007},
  url = {http://euterpe.cmi.ua.ac.be/~vincenz/ADAMUS_paper003.pdf},
  month = {June},
  day = {18},
  }
  
  Abstract:
  Not available

• A Service-oriented Infrastructure Approach for Mutual Assistance Communities
  N. Gui, H. Sun, V. De Florio, & C. Blondia
  Proc. of the First IEEE WoWMoM Workshop on Adaptive and DependAble Mission- and bUsiness-critical mobile Systems (ADAMUS 2007), IEEE Computer Society, 2007.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{,
  author = {N. Gui, H. Sun, V. De Florio, and C. Blondia},
  title = {A Service-oriented Infrastructure Approach for Mutual Assistance Communities},
  booktitle = {Proc. of the First IEEE WoWMoM Workshop on Adaptive and DependAble Mission- and bUsiness-critical mobile Systems (ADAMUS 2007)},
  publisher = {IEEE Computer Society},
  year = {2007},
  month = {June},
  day = {18},
  URL = {content/publications/2007/A%20Service-oriented%20Infrastructure%20for%20Ambient%20Assisted%20Living%20Communities.pdf},
  address = {Helsinki, Finland},
  }
  
  Abstract:
  Not available

• Path-Loss Models for Wireless Communication Channel along Arm and Torso: Measurements and Simulations
  E. Reusens, W. Joseph, G. Vermeeren, L. Martens, B. Latré, B. Braem, C. Blondia & I. Moerman
  2007 IEEE Antennas and Propagation Society International Symposium, Sheraton Waikiki, Honolulu, Hawaii, USA, pp. 345-348, 2007.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{reusens07aps,
  author = { E. Reusens and W. Joseph and G. Vermeeren and L. Martens and B. Latr{\'e} and B. Braem and C. Blondia and I. Moerman},
  title = {Path-Loss Models for Wireless Communication Channel along Arm and Torso: Measurements and Simulations},
  booktitle = {2007 IEEE Antennas and Propagation Society International Symposium},
  year = {2007},
  month = {JUN},
  day = {10-15},
  isbn = {ISBN 1-4244-0878-4},
  pages = {345-348},
  location = {Sheraton Waikiki, Honolulu, Hawaii, USA},
  url = {content/publications/2007/bbraem07APSReusens.pdf},
  abstract = { A Wireless Body Area Network (WBAN) connects independent nodes (e.g., sensors and actuators) that are situated in the clothes, on the body or under the skin of a person. The network typically expands over the whole body and the nodes are connected through a wireless communication channel. A WBAN offers many promising new applications in home/health care, medicine, sports, and many other areas. An important step in the development of a WBAN is the characterization of the physical layer and the description of the electromagnetic wave propagation and antenna behavior near the human body. Propagation near flat, homogeneous and layered phantoms has been investigated in [2]. In this paper, measurements are performed on a real human using two half-wavelength dipoles, considering different parts of the human body separately. Path-loss models are developed for the on-body channels along the arm and torso. The measurement results are verif{}ied with FDTD (Finite-Difference Time-Domain) simulations, using an anatomically correct conf{}iguration of the arms.
  }
  }
  
  Abstract:
  A Wireless Body Area Network (WBAN) connects independent nodes (e.g., sensors and actuators) that are situated in the clothes, on the body or under the skin of a person. The network typically expands over the whole body and the nodes are connected through a wireless communication channel. A WBAN offers many promising new applications in home/health care, medicine, sports, and many other areas. An important step in the development of a WBAN is the characterization of the physical layer and the description of the electromagnetic wave propagation and antenna behavior near the human body. Propagation near flat, homogeneous and layered phantoms has been investigated in [2]. In this paper, measurements are performed on a real human using two half-wavelength dipoles, considering different parts of the human body separately. Path-loss models are developed for the on-body channels along the arm and torso. The measurement results are verified with FDTD (Finite-Difference Time-Domain) simulations, using an anatomically correct configuration of the arms.

• Participant: A New Concept for Optimally Assisting the Elder People
  H. Sun, V. De Florio, N. Gui & C. Blondia
  Proceedings of the 20th IEEE International Symposium on Computer-Based Medical Systems (CBMS-2007), IEEE Computer Society, 2007.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{SDGB07a,
  author = {H. Sun, V. De Florio, N. Gui and C. Blondia},
  title = {Participant: A New Concept for Optimally Assisting the Elder People},
  booktitle = {Proceedings of the 20th IEEE International Symposium on Computer-Based Medical Systems (CBMS-2007)},
  publisher = {IEEE Computer Society},
  year = {2007},
  month = {June},
  day = {20--22},
  address = {Maribor, Slovenia},
  URL = {content/publications/2007/participant.pdf}
  }
  
  Abstract:
  Not available

• Bounds Selection - Dynamic Reset Protocol for Wireless Ad Hoc LANs
  Sylwia Romaszko & Chris Blondia
  Accepted at the IEEE Wireless Communications & Networking Conference (WCNC 2007), Hong Kong, China, 2007.
  BibTeX | Abstract
  
  Bibtex:
  @INPROCEEDINGS{sromaszko07wcnc,
  author = {Sylwia Romaszko and Chris Blondia},
  title = {Bounds Selection - Dynamic Reset Protocol for Wireless Ad Hoc LANs},
  booktitle = {Accepted at the IEEE Wireless Communications & Networking Conference (WCNC 2007)},
  year = {2007},
  location = {Hong Kong, China},
  abstract = {We propose the "Bounds selection - Dynamic Reset Algorithm" (sB-DRA) protocol for wireless ad hoc LANs. The sB-DRA consists of the selection/adjustment of the Contention Window (CW) interval (selection Bounds algorithm - sB from our previous work) and the resetting of the Contention Window value dynamically after a dropped packet or successful transmission (enhanced Dynamic Resetting Algorithm - DRA). The sB algorithm allows to adjust the lower and upper bounds of the CW interval taking into account the number of 1-hop active neighbors and the number of transmission attempts during the recovery mechanism. The DRA considers the number of 1-hop neighbors and their change (fast/slow increase/decrease) during recovery process. The enhanced DRA algorithm can be tuned dynamically depending on the channel conditions. The sB-DRA protocol achieves better throughput and significantly reduces the number of collisions and packet loss compared to the IEEE 802.11 DCF standard. We have also shown that the sB algorithm outperforms the basic (without resetting the Backoff ranges mechanism) "Deterministic Contention Window Algorithm" (DCWA) [ksen] in mobile ad hoc networks.}
  }
  
  Abstract:
  We propose the "Bounds selection - Dynamic Reset Algorithm" (sB-DRA) protocol for wireless ad hoc LANs. The sB-DRA consists of the selection/adjustment of the Contention Window (CW) interval (selection Bounds algorithm - sB from our previous work) and the resetting of the Contention Window value dynamically after a dropped packet or successful transmission (enhanced Dynamic Resetting Algorithm - DRA). The sB algorithm allows to adjust the lower and upper bounds of the CW interval taking into account the number of 1-hop active neighbors and the number of transmission attempts during the recovery mechanism. The DRA considers the number of 1-hop neighbors and their change (fast/slow increase/decrease) during recovery process. The enhanced DRA algorithm can be tuned dynamically depending on the channel conditions. The sB-DRA protocol achieves better throughput and significantly reduces the number of collisions and packet loss compared to the IEEE 802.11 DCF standard. We have also shown that the sB algorithm outperforms the basic (without resetting the Backoff ranges mechanism) "Deterministic Contention Window Algorithm" (DCWA) [ksen] in mobile ad hoc networks.

• A Tool for the Expression of Failure Detection Protocols
  V. De Florio & C. Blondia
  Proceedings of the 15th EUROMICRO Conference on Parallel, Distributed and Network-based Processing (PDP 2007), pp. 199-204, IEEE Computer Society, 2007.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @InProceedings{,
  author = {V. De Florio and C. Blondia},
  title = {A Tool for the Expression of Failure Detection Protocols},
  booktitle = {Proceedings of the 15th EUROMICRO Conference on Parallel, Distributed and Network-based Processing (PDP 2007)},
  publisher = {IEEE Computer Society},
  year = {2007},
  month = {February},
  day = {7--9},
  pages = {199--204},
  URL = {http://euterpe.cmi.ua.ac.be/~vincenz/papers/2007/pdp07.pdf},
  abstract = {Failure detection protocols---an important building block of fault-tolerant distributed systems---are often described by their authors making use of informal pseudo-codes of their own devising. Often these pseudo-codes use syntactical constructs that are not available in COTS programming languages such as C or C++. This translates into informal descriptions that require ad hoc interpretations and implementations. Being informal, these descriptions cannot be tested by their authors, which may translate into insufficiently detailed or even faulty specifications. Being non-standard, they require the reader to understand each time a different lingo. This paper tackles the above problem introducing a formal syntax for the expression of failure detection protocols and a C library that implements that syntax: a toolset to express and reason about failure detection protocols. The resulting specifications are more diffuse but non ambiguous and eligible for becoming a standard form among researchers and practitioners.}
  address = {Naples, Italy},
  }
  
  Abstract:
  Failure detection protocols---an important building block of fault-tolerant distributed systems---are often described by their authors making use of informal pseudo-codes of their own devising. Often these pseudo-codes use syntactical constructs that are not available in COTS programming languages such as C or C++. This translates into informal descriptions that require ad hoc interpretations and implementations. Being informal, these descriptions cannot be tested by their authors, which may translate into insufficiently detailed or even faulty specifications. Being non-standard, they require the reader to understand each time a different lingo. This paper tackles the above problem introducing a formal syntax for the expression of failure detection protocols and a C library that implements that syntax: a toolset to express and reason about failure detection protocols. The resulting specifications are more diffuse but non ambiguous and eligible for becoming a standard form among researchers and practitioners.

2006

• Structured Markov chains solver: software tools
  D. Bini, B. Meini, S. Steffe & B. Van Houdt
  Proceedings of SMCtools 06, ACM Press, Pisa, Italy, 2006.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{bini2,
  author = {D. Bini, B. Meini, S. Steffe and B. Van Houdt},
  title = {Structured Markov chains solver: software tools},
  booktitle = {Proceedings of SMCtools'06, ACM Press},
  year = {2006},
  location = {Pisa, Italy},
  URL = {content/publications/2006/bmsv2_acm.pdf}
  }
  
  Abstract:
  Not available

• Structured Markov chains solver: algorithms
  D. Bini, B. Meini, S. Steffe & B. Van Houdt
  Proceedings of SMCtools 06, ACM Press, Pisa, Italy, 2006.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{bini1,
  author = {D. Bini, B. Meini, S. Steffe and B. Van Houdt},
  title = {Structured Markov chains solver: algorithms },
  booktitle = {Proceedings of SMCtools'06, ACM Press},
  year = {2006},
  location = {Pisa, Italy},
  URL = {content/publications/2006/bmsv1_acm.pdf}
  }
  
  Abstract:
  Not available

• A preventive conversion mechanism for conflict resolution in Optical Burst Switched Networks
  J. Lambert, B. Van Houdt & C. Blondia
  Proceedings of 10th Conference on Optical Network Design and Modelling (ONDM 2006), Copenhagen, Denmark, 2006.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{ONDM2006,
  author={J. Lambert and B. Van Houdt and C. Blondia},
  title={A preventive conversion mechanism for conflict resolution in Optical Burst Switched Networks},
  booktitle = {Proceedings of 10th Conference on Optical Network Design and Modelling (ONDM 2006), Copenhagen, Denmark},
  year = {2006},
  URL = {content/publications/2006/ondm2006_Lambert.Joke.pdf},
  abstract = {In this paper we present an algorithm, called the Wavelength
  before Time with Preventive Conversion (WTPC)
  algorithm, that aims at reducing the loss rate in an optical
  burst switched network. The algorithm resolves contention
  in both the time and wavelength domain and uses a preventive
  conversion mechanism for some optical bursts that
  cause large voids. Without this mechanism our algorithm
  coincides with the Wavelength before Time (WT) algorithm
  of Muretto [7]. We explore two variants of WTPC that differ
  in the Wavelength and Delay Selection algorithm used:
  the minimum Gap and the minimum Length approach, both
  proposed by [2]. A detailed simulation study is included that
  shows the impact of the preventive conversion mechanism on
  the loss and the influence of a variety of parameters, e.g.,
  the number of wavelengths, the number of FDLs and the
  load on the WTPC algorithm.}
  }
  
  Abstract:
  In this paper we present an algorithm, called the Wavelength Time with Preventive Conversion (WTPC) that aims at reducing the loss rate in an optical switched network. The algorithm resolves contention both the time and wavelength domain and uses a preventive mechanism for some optical bursts that large voids. Without this mechanism our algorithm with the Wavelength before Time (WT) algorithm Muretto [7]. We explore two variants of WTPC that differ the Wavelength and Delay Selection algorithm used: minimum Gap and the minimum Length approach, both by [2]. A detailed simulation study is included that the impact of the preventive conversion mechanism on loss and the influence of a variety of parameters, e.g., number of wavelengths, the number of FDLs and the on the WTPC algorithm.

• Dynamic Distributed Contention Window Control in Wireless Ad Hoc LANs
  Sylwia Romaszko & Chris Blondia
  Accepted at the Australian Telecommunication Networks and Applications Conference (ATNAC 06), Melbourne, Australia, 2006.
  BibTeX | Abstract
  
  Bibtex:
  @INPROCEEDINGS{sromaszko06atnac,
  author = {Sylwia Romaszko and Chris Blondia},
  title = {Dynamic Distributed Contention Window Control in Wireless Ad Hoc LANs},
  booktitle = {Accepted at the Australian Telecommunication Networks and Applications Conference (ATNAC'06)},
  year = {2006},
  location = {Melbourne, Australia},
  abstract = {The IEEE DCF 802.11 is currently used as WLAN standard. The standard specifies the contention-based MAC mechanism, Distributed Coordination Function (DCF), which allows to share the wireless channel. In the DCF each node picks a random contention slot from the uniform distribution over the [lower bound, upper bound] interval, where the lower bound always equals 0 and the upper bound equals an integer called Contention Window (CW). We propose three algorithms that modify the distribution of the CW size (lower bound, upper bound and both) based on the number of 1-hop neighbours and the number of transmission attempts. All algorithms achieve a better throughput and significantly reduce the number of collisions and prolong the lifetime of the network compared to the IEEE 802.11 DCF standard.
  }
  }
  
  Abstract:
  The IEEE DCF 802.11 is currently used as WLAN standard. The standard specifies the contention-based MAC mechanism, Distributed Coordination Function (DCF), which allows to share the wireless channel. In the DCF each node picks a random contention slot from the uniform distribution over the [lower bound, upper bound] interval, where the lower bound always equals 0 and the upper bound equals an integer called Contention Window (CW). We propose three algorithms that modify the distribution of the CW size (lower bound, upper bound and both) based on the number of 1-hop neighbours and the number of transmission attempts. All algorithms achieve a better throughput and significantly reduce the number of collisions and prolong the lifetime of the network compared to the IEEE 802.11 DCF standard.

• A Mobile Crisis Management System for Emergency Services: from Concept to Field Test
  S. Bouckaert, J. Bergs, D. Naudts, E. De Kegel, J. Baekelmans, N. Van den Wijngaert, C. Blondia, I. Moerman & P. Demeester
  Proc. The First International Workshop on "Wireless Mesh: Moving towards Applications", Waterloo, Ontario, Canada, 2006.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{Qshine2006,
  author = { S. Bouckaert and J. Bergs and D. Naudts and E. De Kegel and J. Baekelmans and N. Van den Wijngaert and C. Blondia and I. Moerman and P. Demeester},
  title = {A Mobile Crisis Management System for Emergency Services: from Concept to Field Test},
  booktitle = {Proc. The First International Workshop on "Wireless Mesh: Moving towards Applications"},
  year = {2006},
  month = {AUG},
  location = {Waterloo, Ontario, Canada},
  URL = {content/publications/2006/jbergs06mobile.pdf},
  abstract = {During crisis situations, emergency services have to make a lot of crucial decisions, sometimes inevitably based on incomplete or outdated information caused by a lack of means of communication. Wireless ad hoc and mesh networks are a good solution for setting up emergency networks, as they do not rely on f{}ixed infrastructure, can be set up quickly, and provide the necessary communication bandwidth. This paper introduces the GeoBIPS crisis management system architecture, which enables emergency services to collect and combine dynamic on-scene data with static information stored at local or distant servers, using a wireless mesh network. The usability of GeoBIPS has been proven by implementing the architecture on actual hardware which already has been evaluated positively by f{}iremen during a real-life demonstration at a simulated house f{}ire.
  }
  }
  
  Abstract:
  During crisis situations, emergency services have to make a lot of crucial decisions, sometimes inevitably based on incomplete or outdated information caused by a lack of means of communication. Wireless ad hoc and mesh networks are a good solution for setting up emergency networks, as they do not rely on fixed infrastructure, can be set up quickly, and provide the necessary communication bandwidth. This paper introduces the GeoBIPS crisis management system architecture, which enables emergency services to collect and combine dynamic on-scene data with static information stored at local or distant servers, using a wireless mesh network. The usability of GeoBIPS has been proven by implementing the architecture on actual hardware which already has been evaluated positively by firemen during a real-life demonstration at a simulated house fire.

• Performance of Constant Quality Video Applications using the DCCP Transport Protocol
  J. Van Velthoven, K. Spaey & C. Blondia
  Proceedings of the 31st IEEE Conference on Local Computer Networks (LCN 06), Tampa, Florida, USA, pp. 511-512, 2006.
  BibTeX | Abstract | PDF Available | Technical report (extended version)
  
  Bibtex:
  @INPROCEEDINGS{vanvelthoven4,
  author={J. Van Velthoven and K. Spaey and C. Blondia},
  title={Performance of Constant Quality Video Applications using the DCCP Transport Protocol},
  booktitle = {Proceedings of the 31st IEEE Conference on Local Computer Networks (LCN'06)},
  pages = {511--512},
  location = {Tampa, Florida, USA},
  year = {2006},
  month = nov,
  URL = {content/publications/2006/JVV_KS_CB_qualityDCCP_short.pdf},
  techreport = {content/publications/2006/JVV_KS_CB_qualityDCCP.pdf},
  abstract = {In this paper we study the influence the DCCP transport protocol has on the end-user quality of video applications. We consider an application that aims to provide a video of constant quality to the user and introduce a model for such a source. The end-user quality of the application is evaluated in a variety of simulation scenarios.}
  }
  
  Abstract:
  In this paper we study the influence the DCCP transport protocol has on the end-user quality of video applications. We consider an application that aims to provide a video of constant quality to the user and introduce a model for such a source. The end-user quality of the application is evaluated in a variety of simulation scenarios.

• Optimized large file access in storage clusters using common TCP/IP-based file transfer protocols
  S. Eeckhaut, M. Mertens, S. De Smet, B. Vermeulen, L. Andries, M. Peltomaki, N. Van Den Wijngaert, C. Blondia & P. Demeester
  Accepted at SC06, Tampa, FL USA, 2006.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @InProceedings{,
  author = {S. Eeckhaut, M. Mertens, S. De Smet, B. Vermeulen, L. Andries, M. Peltomaki, N. Van Den Wijngaert, C. Blondia, P. Demeester},
  title = {Optimized large file access in storage clusters using
  common TCP/IP-based file transfer protocols},
  year = {2006},
  month = {},
  organization = { },
  booktitle = {Accepted at SC06},
  location = {Tampa, FL USA},
  abstract = {In this paper we took a close look at the
  performance of the TCP/IP stack and some common
  file transfer protocols. Before any real life tests were
  performed, models were created to predict what to expect
  of these protocols. Afterwards, all protocols were
  extensively tested on real setups using some of the latest
  hardware available. Tuning the protocols, OS parameters
  and hardware often improved throughput and diminished
  processing power.
  Out of the current test results, the usability of an IP based
  access network between user terminals and central file
  cluster servers is demonstrated. All tests were performed
  on a scaled setup, including clients, file servers, storage
  controllers and disks, and the architecture was designed
  to be fully scalable. Hence the results presented in this
  paper can immediately be used to design and dimension
  a file-based environment for digital media production.},
  URL = {content/publications/2006/mmertens_IPProtocols.pdf}
  }
  
  Abstract:
  In this paper we took a close look at the of the TCP/IP stack and some common transfer protocols. Before any real life tests were models were created to predict what to expect these protocols. Afterwards, all protocols were tested on real setups using some of the latest available. Tuning the protocols, OS parameters hardware often improved throughput and diminished power. of the current test results, the usability of an IP based network between user terminals and central file servers is demonstrated. All tests were performed a scaled setup, including clients, file servers, storage and disks, and the architecture was designed be fully scalable. Hence the results presented in this can immediately be used to design and dimension a file-based environment for digital media production.

• Evaluation of Surplus Round Robin Scheduling Algorithm
  Dessislava Nikolova & C. Blondia
  Proceedings of the 2006 International Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS 06), Calgary, Alberta, Canada, 2006.
  BibTeX | Abstract
  
  Bibtex:
  @INPROCEEDINGS{SPECTS'06,
  author = { Dessislava Nikolova and C. Blondia},
  title = {Evaluation of Surplus Round Robin Scheduling Algorithm},
  booktitle = {Proceedings of the 2006 International Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS'06)},
  year = {2006},
  month = {AUG},
  location = {Calgary, Alberta, Canada},
  abstract = { In multi-service packet networks the packet scheduling algorithm plays a key role in delivering guaranteed service to different flows. In this article we evaluate surplus round robin (SRR) scheduling algorithm. We apply the Latency-Rate (LR) servers theory in order to obtain bounds on the latency and delay provided by the algorithm. We compare the performance characteristics of SRR with the popular deficit round robin (DRR) algorithm to conclude that SRR can provide better performance than DRR.}
  }
  
  Abstract:
  In multi-service packet networks the packet scheduling algorithm plays a key role in delivering guaranteed service to different flows. In this article we evaluate surplus round robin (SRR) scheduling algorithm. We apply the Latency-Rate (LR) servers theory in order to obtain bounds on the latency and delay provided by the algorithm. We compare the performance characteristics of SRR with the popular deficit round robin (DRR) algorithm to conclude that SRR can provide better performance than DRR.

• The impact of buffer finiteness on the loss rate in a priority queueing system
  J. Van Velthoven, B. Van Houdt & C. Blondia
  EPEW 2006, Lecture Notes in Computer Science, Vol. LNCS 4054, pp. 211-225, 2006.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{vanvelthoven3,
  author={J. Van Velthoven and B. Van Houdt and C. Blondia},
  title={The impact of buffer finiteness on the loss rate in a priority queueing system},
  booktitle = {EPEW 2006},
  series = {Lecture Notes in Computer Science},
  volume = {LNCS 4054},
  pages = {211--225},
  year = {2006},
  month = {JUN},
  URL = {content/publications/2006/Priority_VV_VH_B.pdf},
  abstract = {This paper discusses five different ways to approximate the loss rate in a fundamental two class priority system, where each class has its own finite capacity buffer, as well as an exact approach. We identify the type of error one can expect by assuming that one, or both buffers are of infinite size. Furthermore, we investigate whether asymptotic based results can achieve the same level of accuracy as those based on the actual steady state probabilities. Three novel priority queueing models are introduced and efficient algorithms, relying on matrix analytic methods, are developed within this context. A comparative study based on numerical examples is also included.}
  }
  
  Abstract:
  This paper discusses five different ways to approximate the loss rate in a fundamental two class priority system, where each class has its own finite capacity buffer, as well as an exact approach. We identify the type of error one can expect by assuming that one, or both buffers are of infinite size. Furthermore, we investigate whether asymptotic based results can achieve the same level of accuracy as those based on the actual steady state probabilities. Three novel priority queueing models are introduced and efficient algorithms, relying on matrix analytic methods, are developed within this context. A comparative study based on numerical examples is also included.

• A Design Tool to Reason about Ambient Assisted Living Systems
  H. Sun, V. De Florio & C. Blondia
  Proceedings of the International Conference on Intelligent Systems Design and Applications (ISDA 06), IEEE Computer Society, 2006.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{SDFB06,
  author = {H. Sun and V. De Florio and C. Blondia},
  title = {A Design Tool to Reason about Ambient Assisted Living Systems},
  booktitle = {Proceedings of the International Conference on Intelligent Systems Design and Applications (ISDA'06)},
  publisher = {IEEE Computer Society},
  year = {2006},
  month = {October},
  day = {16--18},
  address = {Jinan, Shandong, P. R. China},
  URL = {content/publications/2006/Isda06.pdf}
  }
  
  Abstract:
  Not available

• Neighbour -Aware, Collision Avoidance MAC Protocol (NCMac) for Mobile Ad Hoc Networks
  Sylwia Romaszko & Chris Blondia
  Third International Symposium on Wireless Communications Systems (ISWCS 06), Valencia, Spain, 2006.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @InProceedings{romaszko06icws,
  author = {Sylwia Romaszko and Chris Blondia},
  title = {Neighbour -Aware, Collision Avoidance MAC Protocol (NCMac) for Mobile Ad Hoc Networks },
  year = {2006},
  booktitle = { Third International Symposium on Wireless Communications Systems (ISWCS'06)},
  location = {Valencia, Spain },
  URL = {content/publications/2006/sromaszko06icws.pdf},
  abstract = {IEEE 802.11 has become the standard for Wireless LAN's both in infrastructure and in ad hoc mode. The standard specifies the medium access control mechanism, Distributed Coordination Function (DCF). Deploying the 802.11 DCF in wireless multi-hop networks leads to inefficient utilization of the bandwidth and energy due to many unnecessary collisions. To attenuate these problems we propose a Neighbour -aware Collision avoidance MAC protocol (NCMac). The NCMac protocol defines algorithms to estimate minimum and maximum Contention Window (CW) sizes (CWmin, CWmax) taking into account the number of neighbours in the one-hop neighbourhood and the energy level of the battery. A novel resetting algorithm applied both after a successful and unsuccessful transmission has been also designed. In [3] we have already proposed a similar algorithm to calculate the CWmin (but not CWmax). However, the resetting algorithm of the NCMac is enhanced and unified and the NCMac does not modify the backoff algorithm defined in [1]. The NCMac protocol achieves a better throughput and noticeably reduces the number of collisions resulting in a longer network lifetime and a later dead of the first node as compared with the IEEE 802.11 DCF standard.
  }
  }
  
  Abstract:
  IEEE 802.11 has become the standard for Wireless LAN s both in infrastructure and in ad hoc mode. The standard specifies the medium access control mechanism, Distributed Coordination Function (DCF). Deploying the 802.11 DCF in wireless multi-hop networks leads to inefficient utilization of the bandwidth and energy due to many unnecessary collisions. To attenuate these problems we propose a Neighbour -aware Collision avoidance MAC protocol (NCMac). The NCMac protocol defines algorithms to estimate minimum and maximum Contention Window (CW) sizes (CWmin, CWmax) taking into account the number of neighbours in the one-hop neighbourhood and the energy level of the battery. A novel resetting algorithm applied both after a successful and unsuccessful transmission has been also designed. In [3] we have already proposed a similar algorithm to calculate the CWmin (but not CWmax). However, the resetting algorithm of the NCMac is enhanced and unified and the NCMac does not modify the backoff algorithm defined in [1]. The NCMac protocol achieves a better throughput and noticeably reduces the number of collisions resulting in a longer network lifetime and a later dead of the first node as compared with the IEEE 802.11 DCF standard.

• A System Architecture for Wireless Building Automation
  W. Vandenberghe, B. Latré, F. D K. Lamont, I. Moerman, M. Mertens, J. Avonts, C. Blondia & G. Impens
  Accepted at IST Mobile & Wireless Communication Summit, Myconos, Greece, 2006.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @InProceedings{,
  author = {W. Vandenberghe, B. Latr{\'e}, F. De Greve, P. De Mil, S. Van den Berghe,
  K. Lamont, I. Moerman, M. Mertens, J. Avonts, C. Blondia, G. Impens},
  title = {A System Architecture for Wireless Building
  Automation},
  year = {2006},
  month = {June},
  organization = {IST },
  booktitle = {Accepted at IST Mobile & Wireless Communication Summit},
  location = {Myconos, Greece},
  abstract = {Wireless Building Automation is a complex problem
  dealing with a lot of trade offs: on one hand sensors and actuators
  have to be as energy-efficient as possible, while on the other hand
  the overall network should be performant and resilient enough
  to extend or even replace a wired backbone. In addition, the
  network should be able to serve existing IEEE 802.11 devices
  such as PDAs, cameras and laptops. Furthermore, surveillance,
  fire detection and other critical building automation applications
  require end-to-end Quality of Service support to ensure the bandwidth
  and delay requirements also in the case of high network
  loads. A networking technology that simultaneously fulfills all
  those requirements does not exist. This paper introduces a system
  architecture that combines heterogeneous technologies into an
  appropriate networking solution.},
  URL = {content/publications/2006/WBA_IST2006_WVDB_final.pdf}
  }
  
  Abstract:
  Wireless Building Automation is a complex problem with a lot of trade offs: on one hand sensors and actuators to be as energy-efficient as possible, while on the other hand overall network should be performant and resilient enough extend or even replace a wired backbone. In addition, the should be able to serve existing IEEE 802.11 devices as PDAs, cameras and laptops. Furthermore, surveillance, detection and other critical building automation applications end-to-end Quality of Service support to ensure the bandwidth delay requirements also in the case of high network A networking technology that simultaneously fulfills all requirements does not exist. This paper introduces a system that combines heterogeneous technologies into an appropriate networking solution.

• The Algorithm of Pipelined Gossiping
  V. De Florio & C. Blondia
  Journal of Systems Architecture, Vol. 52, No. 4, pp. 235-256, Elsevier, 2006.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @Article{DeFl06b,
  author = {V. De Florio, C. Blondia},
  title = {The Algorithm of Pipelined Gossiping},
  journal = {Journal of Systems Architecture},
  year = {2006},
  volume={52},
  number={4},
  pages={235--256},
  publisher={Elsevier},
  abstract={A family of gossiping algorithms depending on a parameter permutation is introduced, formalized, and discussed. Several of its members are analyzed and their asymptotic behaviour is revealed, including a member whose model and performance closely follows the one of hardware pipelined processors. This similarity is exposed. An optimizing algorithm is finally proposed and discussed as
  a general strategy to increase the performance of the base algorithms.},
  URL={http://euterpe.cmi.ua.ac.be/~vincenz/jsa-010-02.pdf}
  }
  
  Abstract:
  A family of gossiping algorithms depending on a parameter permutation is introduced, formalized, and discussed. Several of its members are analyzed and their asymptotic behaviour is revealed, including a member whose model and performance closely follows the one of hardware pipelined processors. This similarity is exposed. An optimizing algorithm is finally proposed and discussed as a general strategy to increase the performance of the base algorithms.

• Dynamics of a Time-outs Management System
  V. De Florio & C. Blondia
  Complex Systems, Vol. 16, No. 3, pp. 209-223, Complex Systems Publications, Champaign, IL, 2006.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @Article{DeFl06,
  author = {V. De Florio, C. Blondia},
  title = {Dynamics of a Time-outs Management System},
  journal = {Complex Systems},
  year = {2006},
  volume={16},
  number={3},
  URL={http://euterpe.cmi.ua.ac.be/~vincenz/cosy.pdf},
  pages={209--223},
  publisher={Complex Systems Publications, Champaign, IL},
  abstract={We call ``time-out'' a software entity that postpones a function call by a given amount of time expressed as local clock ticks. The subject of this paper is a simple software system managing lists of time-outs. We briefly describe that system and discuss its dynamics. We show some experimental results that prove the emergence of complex behaviors.}
  }
  
  Abstract:
  We call time-out a software entity that postpones a function call by a given amount of time expressed as local clock ticks. The subject of this paper is a simple software system managing lists of time-outs. We briefly describe that system and discuss its dynamics. We show some experimental results that prove the emergence of complex behaviors.

• The Wireless Autonomous Spanning Tree Protocol for Multihop Wireless Body Area Networks
  B. Braem, B. Latré, I. Moerman, C. Blondia & P. Demeester
  Mobile and Ubiquitous Systems: Networking & Services, 2006 Third Annual International Conference on, San Jose, California, USA, pp. 1-8, 2006.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{bbraem06wasp,
  author = { B. Braem and B. Latr{\'e} and I. Moerman and C. Blondia and P. Demeester},
  title = {The Wireless Autonomous Spanning Tree Protocol for Multihop Wireless Body Area Networks},
  booktitle = {Mobile and {U}biquitous {S}ystems: {N}etworking & {S}ervices, 2006 {T}hird {A}nnual {I}nternational {C}onference on},
  pages = {1--8},
  year = {2006},
  month = {JUL},
  location = {San Jose, California, USA},
  URL = {content/publications/2006/bbraem06wasp.pdf},
  abstract = {Wireless body area networks (WBANs) have gained a lot of interest in the world of medical monitoring. Current implementations generally use a large single hop network to connect all sensors to a personal server. However recent research pointed out that multihop networks are more energy-efficient and even necessary when applied near the human body with inherent severe propagation loss. In this paper we present a slotted multihop approach to medium access control and routing in wireless body area networks, the Wireless Autonomous Spanning tree Protocol or WASP. It uses crosslayer techniques to achieve efficient distributed coordination of the separated wireless links. Traffic in the network is controlled by setting up a spanning tree and by broadcasting scheme messages over it that are used both by the parent and the children of each node in the tree. We analyze the performance of WASP and show the simulation results.},
  doi = {10.1109/MOBIQ.2006.340421}
  }
  
  Abstract:
  Wireless body area networks (WBANs) have gained a lot of interest in the world of medical monitoring. Current implementations generally use a large single hop network to connect all sensors to a personal server. However recent research pointed out that multihop networks are more energy-efficient and even necessary when applied near the human body with inherent severe propagation loss. In this paper we present a slotted multihop approach to medium access control and routing in wireless body area networks, the Wireless Autonomous Spanning tree Protocol or WASP. It uses crosslayer techniques to achieve efficient distributed coordination of the separated wireless links. Traffic in the network is controlled by setting up a spanning tree and by broadcasting scheme messages over it that are used both by the parent and the children of each node in the tree. We analyze the performance of WASP and show the simulation results.

• Dimensioning of a Dejittering Buffer for Variable Bit Rate Video Streams
  K. Spaey & C. Blondia
  Proceedings of the 13th International Conference on Analytical and Stochastic Modelling Techniques and Applications (ASMTA 2006), Bonn, Germany, pp. 61-68, 2006.
  BibTeX | PDF Available
  
  Bibtex:
  @InProceedings{ASMTA2006,
  author = {K. Spaey, C. Blondia},
  title = {Dimensioning of a Dejittering Buffer for Variable Bit Rate Video Streams},
  booktitle = {Proceedings of the 13th International Conference on Analytical and Stochastic Modelling Techniques and Applications (ASMTA 2006)},
  pages = {61--68},
  year = {2006},
  month = may,
  location = {Bonn, Germany},
  URL = {content/publications/2006/ASMTA2006.pdf}
  }
  
  Abstract:
  Not available

• REACT: Routing Protocol for Emergency Applications in Car-to-Car Networks using Trajectories
  Erwin Van de Velde, Chris Blondia & Luca Campelli
  Proceedings of Mediterranean Ad Hoc Networking Workshop, Lipari, Italy, 2006.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @InProceedings{medhoc2006,
  author = {Erwin Van de Velde, Chris Blondia, Luca Campelli},
  title = {REACT: Routing Protocol for Emergency Applications in Car-to-Car Networks using Trajectories},
  year = {2006},
  month = {June},
  organization = {MedHoc},
  booktitle = {Proceedings of Mediterranean Ad Hoc Networking Workshop},
  location = {Lipari, Italy},
  abstract = {Traffic safety is a very important issue in modern society and the last couple of years researchers have started looking at telecommunication solutions to enhance traffic safety. More specifically researchers are looking at emergency alert services, enabling cars to warn eachother for incidents (slippery road, accident, \ldots). Existing forwarding protocols for vehicular networks often use an approach based on geographical information as a topology based forwarding protocol fails to adapt to the quick movement of the vehicles. A geographical based approach however uses only a part of the information available to the system. In this paper a new routing algorithm, REACT, will be proposed, using not only geographical information, for both position and speed, but also road map information. Using the knowledge of both neighbors and road maps, a node that wants to send a packet can choose the best forwarder along a given trajectory.},
  URL = {content/publications/2006/medhoc2006.pdf}
  }
  
  Abstract:
  Traffic safety is a very important issue in modern society and the last couple of years researchers have started looking at telecommunication solutions to enhance traffic safety. More specifically researchers are looking at emergency alert services, enabling cars to warn eachother for incidents (slippery road, accident, \ldots). Existing forwarding protocols for vehicular networks often use an approach based on geographical information as a topology based forwarding protocol fails to adapt to the quick movement of the vehicles. A geographical based approach however uses only a part of the information available to the system. In this paper a new routing algorithm, REACT, will be proposed, using not only geographical information, for both position and speed, but also road map information. Using the knowledge of both neighbors and road maps, a node that wants to send a packet can choose the best forwarder along a given trajectory.

• Transient analysis of tree-like processes and its application to random access systems
  J. Van Velthoven, B. Van Houdt & C. Blondia
  ACM Sigmetrics Performance Evaluation Review, Vol. 34, No. 1, pp. 181-190, 2006.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{vanvelthoven_sigm,
  author = {J. Van Velthoven, B. Van Houdt and C. Blondia},
  title = {Transient analysis of tree-like processes and its application to random access systems},
  booktitle = { ACM Sigmetrics Performance Evaluation Review},
  pages= {181--190},
  volume={34},
  number={1}
  year = {2006},
  month = {JUN},
  url = {content/publications/2006/Treelike_marked.pdf},
  abstract = {A new methodology to assess transient performance measures of tree-like processes is proposed by introducing the concept of tree-like processes with marked time epochs. As opposed to the standard tree-like process, such a process marks part of the time epochs by following a set of Markovian rules.
  Our interest lies in obtaining the system state at the n-th marked time epoch as well as the mean time at which this n-th marking occurs. The methodology transforms the transient problem into a stationary one by applying a discrete Erlangization and constructing a reset Markov chain. A fast algorithm, with limited memory usage, that exploits the block structure of the reset Markov
  chain is developed and is based, among others, on Sylvester matrix equations and fast Fourier transforms. The theory of tree-like processes generalizes the well-known paradigm of Quasi-Birth-Death Markov chains and has various applications. We demonstrate our approach on the celebrated Capetanakis-Tsybakov-Mikhailov (CTM) random access protocol yielding new insights on its initial behavior both in normal and overload conditions. }
  }
  
  Abstract:
  A new methodology to assess transient performance measures of tree-like processes is proposed by introducing the concept of tree-like processes with marked time epochs. As opposed to the standard tree-like process, such a process marks part of the time epochs by following a set of Markovian rules. interest lies in obtaining the system state at the n-th marked time epoch as well as the mean time at which this n-th marking occurs. The methodology transforms the transient problem into a stationary one by applying a discrete Erlangization and constructing a reset Markov chain. A fast algorithm, with limited memory usage, that exploits the block structure of the reset Markov is developed and is based, among others, on Sylvester matrix equations and fast Fourier transforms. The theory of tree-like processes generalizes the well-known paradigm of Quasi-Birth-Death Markov chains and has various applications. We demonstrate our approach on the celebrated Capetanakis-Tsybakov-Mikhailov (CTM) random access protocol yielding new insights on its initial behavior both in normal and overload conditions.

• On the Generality of Binary Tree-like Markov Chains
  K. Spaey, B. Van Houdt & C. Blondia
  Proceedings of MAM 2006: Markov Aniversary Meeting, Charleston, USA, pp. 79-88, Boston Books, 2006.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{markovMeeting,
  author = {K. Spaey and B. Van Houdt and C. Blondia},
  title = {On the Generality of Binary Tree-like Markov Chains},
  booktitle = {Proceedings of MAM 2006: Markov Aniversary Meeting},
  pages = {79--88},
  year = {2006},
  month = jun,
  location = {Charleston, USA},
  publisher = {Boston Books},
  URL = {content/publications/2006/binary_tree2.pdf}
  }
  
  Abstract:
  Not available

• Analyzing priority queues with 3 classes using tree-like processes
  B. Van Houdt & C. Blondia
  To appear in Queueing Systems, 2006.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{vanhoudtQUEST2006,
  author = {B. Van Houdt and C. Blondia},
  title = {Analyzing priority queues with 3 classes using tree-like processes},
  booktitle = {To appear in Queueing Systems},
  year = {2006},
  URL = {content/publications/2006/stack.pdf}
  }
  
  Abstract:
  Not available

• An integrated production and inventory model to dampen upstream demand variability in the supply chain
  R.N. Boute, S.M. Disney, M.R. Lambrecht & B. Van Houdt
  To appear in European Journal of Operational Research, 2006.
  BibTeX | PDF Available
  
  Bibtex:
  @ATRICLE{vanhoudtEJOR2006,
  AUTHOR={R.N. Boute and S.M. Disney and M.R. Lambrecht and B. Van Houdt },
  TITLE={An integrated production and inventory model to dampen upstream demand variability in the supply chain},
  JOURNAL={To appear in European Journal of Operational Research},
  YEAR={2006},
  URL = {content/publications/2006/EJOR2006.pdf}}
  
  Abstract:
  Not available

• Linking priority queues and tree-like processes
  B. Van Houdt & C. Blondia
  AEU International Journal of Electronics and Communications, Vol. 60, pp. 2, 2006.
  BibTeX | PDF Available
  
  Bibtex:
  @ATRICLE{vanhoudtAEU,
  AUTHOR={B. Van Houdt and C. Blondia},
  TITLE={Linking priority queues and tree-like processes},
  JOURNAL={AEU International Journal of Electronics and Communications},
  VOLUME={60},
  PAGES={2},
  ISSUE={131-135},
  YEAR={2006},
  URL = {content/publications/2006/AEU_vhb.pdf}}
  
  Abstract:
  Not available

• An L2 Transmission Feedback based buffering scheme for Mobile IP handovers in an IEEE 802.11 wireless network.
  P. De Cleyn & C. Blondia
  WSEAS Transactions on communications, Vol. 5, No. 6, pp. 1055-1060, 2006.
  BibTeX
  
  Bibtex:
  @ARTICLE{feedback,
  author = {P. De Cleyn and C. Blondia},
  title = {An L2 Transmission Feedback based buffering scheme for Mobile IP handovers in an IEEE 802.11 wireless network.},
  booktitle = {WSEAS Transactions on communications},
  volume = {5},
  number = {6},
  pages = {1055--1060},
  year = {2006},
  month = {JUN}
  }
  
  Abstract:
  Not available

• On the probability of abandonment in queues with limited sojourn and waiting times
  J. Van Velthoven, B. Van Houdt & C. Blondia
  Operations and Research Letters, Vol. 34, No. 3, pp. 333-338, 2006.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @ARTICLE{total,
  author = {J. Van Velthoven, B. Van Houdt and C. Blondia},
  title = {On the probability of abandonment in queues with limited sojourn and waiting times},
  booktitle = {Operations and Research Letters},
  volume = {34},
  number = {3},
  pages = {333--338},
  year = {2006},
  URL = {content/publications/2006/OR_impatient.pdf},
  abstract = {Consider the Geo/Geo/1 queue with impatient customers and let X reflect the patience distribution. We show that systems with a smaller patience distribution X in the convex-ordering sense give rise to fewer abandonments (due to impatience), irrespective of whether customers become patient when entering the service facility.}
  }
  
  Abstract:
  Consider the Geo/Geo/1 queue with impatient customers and let X reflect the patience distribution. We show that systems with a smaller patience distribution X in the convex-ordering sense give rise to fewer abandonments (due to impatience), irrespective of whether customers become patient when entering the service facility.

• Neighbour and Energy -Aware Contention Avoidance MAC Protocol for Wireless Ad Hoc Networks
  Sylwia Romaszko & Chris Blondia
  To appear in the Proceedings of 2nd IEEE International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob 2006), Montreal, Canada, 2006.
  BibTeX | Abstract
  
  Bibtex:
  @INPROCEEDINGS{romaszko06neighbour,
  author = {Sylwia Romaszko and Chris Blondia},
  title = {Neighbour and Energy -Aware Contention Avoidance MAC Protocol for Wireless Ad Hoc Networks},
  booktitle = {To appear in the Proceedings of 2nd IEEE International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob 2006)},
  year = {2006},
  location = {Montreal, Canada},
  abstract = {The IEEE DCF 802.11, currently used as wireless local area networking standard, wastes bandwidth capacity and energy resources due to many collisions. To attenuate these problems we propose a Neighbour and Energy aWare Contention Avoidance MAC protocol (NEWCAMac). The NEWCAMac protocol defines novel algorithms to estimate a minimum and maximum Contention Window size taking into account the number of neighbours in the one-hop neighbourhood and the energy level of the battery. It also exploits a new backoff algorithm based on the number of currently active neighbours and the probability of successful transmission. Our novel protocol achieves better throughput and noticeably reduces the number of collisions resulting in longer network lifetime as compared with the IEEE 802.11 DCF standard.}
  }
  
  Abstract:
  The IEEE DCF 802.11, currently used as wireless local area networking standard, wastes bandwidth capacity and energy resources due to many collisions. To attenuate these problems we propose a Neighbour and Energy aWare Contention Avoidance MAC protocol (NEWCAMac). The NEWCAMac protocol defines novel algorithms to estimate a minimum and maximum Contention Window size taking into account the number of neighbours in the one-hop neighbourhood and the energy level of the battery. It also exploits a new backoff algorithm based on the number of currently active neighbours and the probability of successful transmission. Our novel protocol achieves better throughput and noticeably reduces the number of collisions resulting in longer network lifetime as compared with the IEEE 802.11 DCF standard.

• Analyzing the Impact of Neighbor Sensing on the Performance of the OLSR protocol
  M. Voorhaen & C. Blondia
  Proceedings of 4th Intl. Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt06), Boston, Massachusetts, 2006.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{voorhaen06wioptimpact,
  author = {M. Voorhaen and C. Blondia},
  title = {Analyzing the Impact of Neighbor Sensing on the Performance of the OLSR protocol},
  booktitle = {Proceedings of 4th Intl. Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt06)},
  year = {2006},
  month = {APRIL},
  location = {Boston, Massachusetts},
  abstract = {This paper presents an analysis of several neighbor sensing approaches for the OLSR routing protocol. While several performance studies of OLSR proceed this work, few attention has been paid to the impact of neighbor sensing on the performance of ad hoc routing protocols. The goal of this article is to better understand how neighbor sensing can contribute to packet loss in an OLSR network and thus degrade the overall performance. Three neighbor sensing schemes are compared: the OLSR HELLO messaging protocol, Fast-OLSR and a link layer feedback scheme that uses information of the 802.11 MAC to determine lost links. To allow more detailed analysis of the events occuring in the network we initially limit our simulation setup to simple scenarios. As a result we are able to seperate the loss of packets into loss due to the the neighbor sensing mechanism used and loss due to the impact of neighbor sensing on the other protocol operations.},
  notes = {Still working on the camera ready.},
  url = {content/publications/2006/mvhaen06wiopt.pdf}
  }
  
  Abstract:
  This paper presents an analysis of several neighbor sensing approaches for the OLSR routing protocol. While several performance studies of OLSR proceed this work, few attention has been paid to the impact of neighbor sensing on the performance of ad hoc routing protocols. The goal of this article is to better understand how neighbor sensing can contribute to packet loss in an OLSR network and thus degrade the overall performance. Three neighbor sensing schemes are compared: the OLSR HELLO messaging protocol, Fast-OLSR and a link layer feedback scheme that uses information of the 802.11 MAC to determine lost links. To allow more detailed analysis of the events occuring in the network we initially limit our simulation setup to simple scenarios. As a result we are able to seperate the loss of packets into loss due to the the neighbor sensing mechanism used and loss due to the impact of neighbor sensing on the other protocol operations.

• Queues with correlated inter-arrival and service times and its application to optical buffers
  J. Lambert, B. Van Houdt & C. Blondia
  Stochastic Models, Vol. 22, No. 2, pp. 233-251, 2006.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @ARTICLE{SM1447,
  author = {J. Lambert, B. Van Houdt and C. Blondia},
  title = {Queues with correlated inter-arrival and service times and its application to optical buffers},
  booktitle = {Stochastic Models},
  year = {2006},
  volume = {22},
  pages = {233--251}
  number = {2},
  URL = {content/publications/2005/SM1447.pdf}
  abstract = {This paper presents an algorithmic procedure to calculate the queue length and delay
  distribution of customers in a discrete time D-MAP/PH/1 queue, where the service time
  distribution of a customer depends on the inter-arrival time between himself and his
  predecessor. Setting up a Markov chain that keeps track of the contents of such a queue
  will result in a state space explosion as the inter-arrival times of all customers present in
  the system must be remembered. We avoid these difficulties by making use of the age
  process. This process keeps track of the "age" of the customer in the service facility.
  From this process, which we solve by means of matrix analytic methods, we compute the
  queue length and sojourn time distribution by means of a simple formula and obtain an
  expression for the stability of the system. We also demonstrate that the D-MAP arrival
  process can be easily replaced by the more general semi-Markovian arrival process, without
  any additional computational costs. Queueing systems of this type arise in the domain of
  synchronous optical buffers. Based on the numerical analysis of such a queueing system,
  some guidelines for the design of optical buffers are presented. We also show the impact
  on the numerical results when the cross-correlation that exists between the service and
  inter-arrival times is neglected.}
  }
  
  Abstract:
  This paper presents an algorithmic procedure to calculate the queue length and delay of customers in a discrete time D-MAP/PH/1 queue, where the service time of a customer depends on the inter-arrival time between himself and his Setting up a Markov chain that keeps track of the contents of such a queue result in a state space explosion as the inter-arrival times of all customers present in system must be remembered. We avoid these difficulties by making use of the age This process keeps track of the "age" of the customer in the service facility. this process, which we solve by means of matrix analytic methods, we compute the length and sojourn time distribution by means of a simple formula and obtain an for the stability of the system. We also demonstrate that the D-MAP arrival can be easily replaced by the more general semi-Markovian arrival process, without additional computational costs. Queueing systems of this type arise in the domain of optical buffers. Based on the numerical analysis of such a queueing system, guidelines for the design of optical buffers are presented. We also show the impact the numerical results when the cross-correlation that exists between the service and times is neglected.

2005

• Enhancements of the IEEE 802.11, a MAC Protocol for Ad Hoc Network with History of Power Adjustment
  Sylwia Romaszko & Chris Blondia
  Proceedings of the 3rd IEEE International Workshop on Mobility Management and Wireless Access (MobiWac 2005), Maui, Hawaii, USA, 2005.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{romaszko05mobiwac,
  author = {Sylwia Romaszko and Chris Blondia},
  title = {Enhancements of the IEEE 802.11, a MAC Protocol for Ad Hoc Network with History of Power Adjustment},
  booktitle = {Proceedings of the 3rd IEEE International Workshop on Mobility Management and Wireless Access (MobiWac 2005)},
  year = {2005},
  location = {Maui, Hawaii, USA},
  abstract = {We propose a MAC protocol which improves disadvantages of the IEEE 802.11 DCF standard, like the blocking problem, scheduling concurrent transmissions (the hidden and exposed problem). Our protocol also achieves better spatial reuse of the spectrum thanks to the power control taking into consideration the number of neighbors in the one-hop neighborhood and the history of power changes. Through many simulations we show that our algorithm outperforms the IEEE 802.11 standard both in the static and dynamic network and also in high interference environments.},
  url={content/publications/2005/1568962678.pdf}
  }
  
  Abstract:
  We propose a MAC protocol which improves disadvantages of the IEEE 802.11 DCF standard, like the blocking problem, scheduling concurrent transmissions (the hidden and exposed problem). Our protocol also achieves better spatial reuse of the spectrum thanks to the power control taking into consideration the number of neighbors in the one-hop neighborhood and the history of power changes. Through many simulations we show that our algorithm outperforms the IEEE 802.11 standard both in the static and dynamic network and also in high interference environments.

• QoS Management in WIDENS Terminodes
  L. Cerdà, R. Guimarães, J.Morillo, J.M. Barceló, J. García, A. Perez-Neira, M. Realp, M. Voorhaen, C. Blondia, R. Knopp & N. Nikaein
  2nd EVEREST Workshop on Trends in Radio Resource Management, Barcelona, Spain, 2005.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{mvhaen05everest,
  author = {L. Cerd{\`a} and R. Guimar{\^a}es and J.Morillo and J.M. Barcel{\'o} and J. Garc{\'i}a and A. Perez-Neira and M. Realp and M. Voorhaen and C. Blondia and R. Knopp and N. Nikaein},
  title = {QoS Management in WIDENS Terminodes},
  booktitle = {2nd EVEREST Workshop on Trends in Radio Resource Management},
  year = {2005},
  month = {NOV},
  location = {Barcelona, Spain},
  URL = {content/publications/2005/mvhaen05everest.pdf},
  abstract = {The paper has two parts: First, we present an
  overview of the IST WIreless DEployable Network System
  (WIDENS) Project. This project aims to define an easily deployable communication system to be used by emergency services and public safety in general. In this context, users require a communication system that should not depend on pre-existent infrastructure, and could support real time applications, so that firefighters, policemen, doctors (and others) can collaborate efficiently. In order to meet these requirements, WIDENS implements a wireless ad-hoc network with Quality of Service (QoS) support. Second, the paper focuses on the QoS approach used in WIDENS. This approach is based on a bandwidth reservation scheme. Additionally, we give some simulation results showing the advantages of the reservation scheme.}
  }
  
  Abstract:
  The paper has two parts: First, we present an of the IST WIreless DEployable Network System Project. This project aims to define an easily deployable communication system to be used by emergency services and public safety in general. In this context, users require a communication system that should not depend on pre-existent infrastructure, and could support real time applications, so that firefighters, policemen, doctors (and others) can collaborate efficiently. In order to meet these requirements, WIDENS implements a wireless ad-hoc network with Quality of Service (QoS) support. Second, the paper focuses on the QoS approach used in WIDENS. This approach is based on a bandwidth reservation scheme. Additionally, we give some simulation results showing the advantages of the reservation scheme.

• QBDs with marked time epochs: a framework for transient measures
  B. Van Houdt & C. Blondia
  Proc. of QEST 2006, Torino - Italy, pp. 210-219, IEEE Computer Society, 2005.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{vanhoudtQEST,
  AUTHOR=B. Van Houdt, C. Blondia,
  TITLE={QBDs} with marked time epochs: a framework for transient
  performance measures,
  BOOKTITLE=Proc. of QEST 2006,
  PUBLISHER=IEEE Computer Society,
  LOCATION=Torino - Italy,
  PAGES=210-219,
  YEAR=2005,
  URL = {content/publications/2005/QEST05.pdf}
  }
  
  Abstract:
  Not available

• Single-wavelength optical buffers: non-equidistant structures and preventive drop mechanisms
  J. Lambert, B. Van Houdt & C. Blondia
  Proceedings of the 2005 Networking and Electronic Commerce Research Conference (NAEC 2005), Riva Del Garda, pp. 545-555, 2005.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @ARTICLE{Lamb_VanH_Blon_NAEC2005,
  author = {J. Lambert, B. Van Houdt and C. Blondia},
  title = {Single-wavelength optical buffers: non-equidistant structures and preventive drop mechanisms},
  booktitle = {Proceedings of the 2005 Networking and Electronic Commerce Research Conference (NAEC 2005)},
  year = {2005},
  pages = {545-555},
  month = {OCT},
  location = {Riva Del Garda},
  URL = {content/publications/2005/Lamb_VanH_Blon_NAEC2005.pdf}
  abstract={We present two approaches that aim at reducing the loss rates in an optical
  buffer having access to a single outgoing channel. As opposed to a
  conventional electronic buffer, such a system - consisting of a number of
  fibre delay lines (FDLs) - can only realize a discrete set of delay values to
  resolve contention. This leads to voids on the outgoing channel, which increases
  the losses. Traditionally the FDL lengths are equidistant. Our first
  approach distinguishes itself by allowing more flexibility on the delay line
  lengths. Conditions on which improvements can be achieved are discussed.
  These conditions are obtained by defining several heuristic algorithms. The
  second approach tries to reduce channel losses by preliminary discards of
  optical burst that cause large voids. To perform this analysis we make use
  of a Markov Decision Process. Moreover we present a comparative study
  between these two approaches and the traditional situation.}
  }
  
  Abstract:
  We present two approaches that aim at reducing the loss rates in an optical having access to a single outgoing channel. As opposed to a electronic buffer, such a system - consisting of a number of delay lines (FDLs) - can only realize a discrete set of delay values to contention. This leads to voids on the outgoing channel, which increases losses. Traditionally the FDL lengths are equidistant. Our first distinguishes itself by allowing more flexibility on the delay line Conditions on which improvements can be achieved are discussed. conditions are obtained by defining several heuristic algorithms. The approach tries to reduce channel losses by preliminary discards of burst that cause large voids. To perform this analysis we make use a Markov Decision Process. Moreover we present a comparative study these two approaches and the traditional situation.

• The Response Time in a Tandem Queue with Blocking, Markovian Arrivals and Phase-Type Services
  B. Van Houdt & A.S. Alfa
  Operations Research (OR) Letters, Vol. 33, No. 4, pp. 373-381, 2005.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{OPERES,
  author = {B. Van Houdt and A.S. Alfa},
  title = {The Response Time in a Tandem Queue with Blocking, Markovian Arrivals and Phase-Type Services},
  booktitle = {Operations Research (OR) Letters},
  volume = {33},
  number = {4},
  year = {2005},
  pages = {373-381},
  month = {JUL},
  URL = {content/publications/2005/OPERES.pdf}
  }
  
  Abstract:
  Not available

• MORHE: A Transparant Multi-level Routing Scheme for Ad Hoc Networks
  M. Voorhaen, E. Van de Velde & C. Blondia
  Proceedings of the Fourth Annual Mediterranean Ad Hoc Networking Workshop (MED-HOC-NET 2005), Île de Porquerolles, France, 2005.
  BibTeX | Abstract | PDF Available | Technical report (extended version)
  
  Bibtex:
  @INPROCEEDINGS{med_hoc_morhe,
  author = {M. Voorhaen, E. Van de Velde and C. Blondia},
  title = {MORHE: A Transparant Multi-level Routing Scheme for Ad Hoc Networks},
  booktitle = { Proceedings of the Fourth Annual Mediterranean Ad Hoc Networking Workshop (MED-HOC-NET 2005)},
  year = {2005},
  month = {JUN},
  location = {{\^I}le de Porquerolles, France},
  URL = {content/publications/2005/med_hoc_morhe.pdf},
  techreport = {content/publications/2005/technical_report_morhe.pdf},
  abstract = {This paper presents a transparent multi-level routing scheme, named MORHE, that improves the scalability of the OLSR protocol by exploiting the heterogeneous nature of nodes in the network. While ad hoc networks have been an active research topic over the past few years, the majority of the studies have focused on the homogeneous nature of the network. In our work we try to take a different approach by focusing on scenarios where ad hoc technology can be applied, but where we also find nodes in the network with varying capacity. The MORHE protocol makes use of nodes which have a large capacity (e.g. more energy, larger transmission range) to build something that could best be described as an ad hoc infrastructure. Nodes are grouped in clusters that need to be interconnected by specific nodes.This implies that a node no longer needs to know the entire network topology as is the case of the OLSR protocol, but only needs to maintain routes to the nodes inside its own cluster and to the other clusters.Using this approach the signalling overhead - which is one of the main reasons why OLSR is not scalable - is greatly reduced. We also introduce a simple mobility management scheme to allow nodes to roam the different ad hoc clusters.}
  }
  Abstract: We propose a MAC protocol which achieves better spatial reuse of spectrum thanks to power adjustments based on the number of neighbors in the one-hop neighborhood. Through many simulations we show that our algorithm outperforms the IEEE 802.11 standard, also in high interference environments.
  
  Abstract:
  This paper presents a transparent multi-level routing scheme, named MORHE, that improves the scalability of the OLSR protocol by exploiting the heterogeneous nature of nodes in the network. While ad hoc networks have been an active research topic over the past few years, the majority of the studies have focused on the homogeneous nature of the network. In our work we try to take a different approach by focusing on scenarios where ad hoc technology can be applied, but where we also find nodes in the network with varying capacity. The MORHE protocol makes use of nodes which have a large capacity (e.g. more energy, larger transmission range) to build something that could best be described as an ad hoc infrastructure. Nodes are grouped in clusters that need to be interconnected by specific nodes.This implies that a node no longer needs to know the entire network topology as is the case of the OLSR protocol, but only needs to maintain routes to the nodes inside its own cluster and to the other clusters.Using this approach the signalling overhead - which is one of the main reasons why OLSR is not scalable - is greatly reduced. We also introduce a simple mobility management scheme to allow nodes to roam the different ad hoc clusters. We propose a MAC protocol which achieves better spatial reuse of spectrum thanks to power adjustments based on the number of neighbors in the one-hop neighborhood. Through many simulations we show that our algorithm outperforms the IEEE 802.11 standard, also in high interference environments.

• A Reservation Scheme Satisfying Bandwidth QoS Constraints for Multirate Ad-Hoc Networks
  L. Cerdà, M. Voorhaen, R. Guimarães, J.M. Barceló, J. García & C. Blondia
  Proceedings of the IST Mobile & Wireless Communications Summit 2005, Dresden, Germany, 2005.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{ist_multirate,
  author = {L. Cerd{\`a} and M. Voorhaen and R. Guimar{\^a}es and J.M. Barcel{\'o} and J. Garc{\'i}a and C. Blondia},
  title = {A Reservation Scheme Satisfying Bandwidth QoS Constraints for Multirate Ad-Hoc Networks},
  booktitle = {Proceedings of the IST Mobile & Wireless Communications Summit 2005},
  year = {2005},
  month = {JUN},
  location = {Dresden, Germany},
  URL = {content/publications/2005/ist_multirate.pdf},
  abstract = { Achieving QoS (Quality of Service) in Mobile Ad-hoc NETworks (MANET) has been a research topic in the last years. In this paper we describe a QoS reservation mechanism for Multirate Ad-hoc Networks. By multirate we refer to those networks where the mobile nodes can dynamically switch between several link rates. This allows the mobile nodes to select the transmission rate with better performance for every neighbor. The mechanism is targeted for sources requiring a bandwidth allocation. The mechanism is based on the knowledge of the bandwidth requirements of the neighbors of a node and the interferent nodes in the coverage area of each node. We describe as the protocol could be integrated in AODV and OLSR. We also give simulation results showing the advantages of our reservation scheme.}
  }
  
  Abstract:
  Achieving QoS (Quality of Service) in Mobile Ad-hoc NETworks (MANET) has been a research topic in the last years. In this paper we describe a QoS reservation mechanism for Multirate Ad-hoc Networks. By multirate we refer to those networks where the mobile nodes can dynamically switch between several link rates. This allows the mobile nodes to select the transmission rate with better performance for every neighbor. The mechanism is targeted for sources requiring a bandwidth allocation. The mechanism is based on the knowledge of the bandwidth requirements of the neighbors of a node and the interferent nodes in the coverage area of each node. We describe as the protocol could be integrated in AODV and OLSR. We also give simulation results showing the advantages of our reservation scheme.

• WIDENS: Advanced Wireless Ad-Hoc Networks for Public Safety
  H. Aïache, V. Conan, G. Guibé, J. Leguay, C. Le Martret, J.M. Barceló, L. Cerdà, J. García, R. Knopp, N. Nikaein, X. Gonzalez, A. Zeini, O. Apilo, A. Boukalov, J. Karvo, H. Koskinen, L. Bergonzi, J. Diaz, J. Meessen, C. Blondia, P. De Cleyn, E. Van de Velde & M. Voorhaen
  Proceedings of the IST Mobile & Wireless Communications Summit 2005, Dresden, Germany, 2005.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{ist_widens,
  author = {H. A{\"i}ache and V. Conan and G. Guib{\'e} and J. Leguay and C. Le Martret and J.M. Barcel{\'o} and L. Cerd{\`a} and J. Garc{\'i}a and R. Knopp and N. Nikaein and X. Gonzalez and A. Zeini, O. Apilo and A. Boukalov and J. Karvo and H. Koskinen and L. Bergonzi and J. Diaz and J. Meessen and C. Blondia and P. De Cleyn and E. Van de Velde and M. Voorhaen},
  title = {WIDENS: Advanced Wireless Ad-Hoc Networks for Public Safety},
  booktitle = {Proceedings of the IST Mobile & Wireless Communications Summit 2005},
  year = {2005},
  month = {JUN},
  location = {Dresden, Germany},
  URL = {content/publications/2005/ist_widens.pdf},
  abstract= {This paper provides an overview of the on-going European Project called WIreless DEployable Network System (WIDENS) which aims at defining a rapidly deployable communication system for public safety or emergency services. In this context, users expect a highly reliable communication system that can support real time applications to allow teams to collaborate in an efficient way. They also want the system to work in a spontaneous fashion and with no pre-installed infrastructures. To fit all the requirements, WIDENS takes advantage of the technology of wireless ad hoc networks to establish high data rate communication links on the fly. In this paper we describe the overall architecture of the WIDENS network and highlight the design of its major components.}
  }
  
  Abstract:
  This paper provides an overview of the on-going European Project called WIreless DEployable Network System (WIDENS) which aims at defining a rapidly deployable communication system for public safety or emergency services. In this context, users expect a highly reliable communication system that can support real time applications to allow teams to collaborate in an efficient way. They also want the system to work in a spontaneous fashion and with no pre-installed infrastructures. To fit all the requirements, WIDENS takes advantage of the technology of wireless ad hoc networks to establish high data rate communication links on the fly. In this paper we describe the overall architecture of the WIDENS network and highlight the design of its major components.

• A System Structure for Adaptive Mobile Applications
  V. De Florio & C. Blondia
  Proceedings of the IEEE International Symposium on a World of Wireless, Mobile and Multimedia Networks 2005 (WOWMOM 2005), Giardini Naxos, Italy, 2005.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{wowmom,
  author = {V. De Florio and C. Blondia},
  title = {A System Structure for Adaptive Mobile Applications},
  booktitle = {Proceedings of the IEEE International Symposium on a World of Wireless, Mobile and Multimedia Networks 2005 (WOWMOM 2005)},
  year = {2005},
  month = {JUN},
  location = {Giardini Naxos, Italy},
  URL = {content/publications/2005/wowmom.pdf}
  }
  
  Abstract:
  Not available

• A MAC Protocol for Wireless Ad Hoc Networks with Power Control
  Sylwia Romaszko & Chris Blondia
  Proceedings of the International Workshop on Wireless Ad-hoc Networks 2005 (IWWAN 2005), London, UK, No. 54, 2005.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{romaszko,
  author = {Sylwia Romaszko and Chris Blondia},
  title = {A MAC Protocol for Wireless Ad Hoc Networks with Power Control},
  booktitle = { Proceedings of the International Workshop on Wireless Ad-hoc Networks 2005 (IWWAN 2005)},
  number = {54},
  year = {2005},
  month = {MAY},
  location = {London, UK},
  abstract = {We propose a MAC protocol which achieves better spatial reuse of spectrum thanks to power adjustments based on the number of neighbors in the one-hop neighborhood. Through many simulations we show that our algorithm outperforms the IEEE 802.11 standard, also in high interference environments.},
  URL = {content/publications/2005/romaszko.pdf}
  }
  
  Abstract:
  We propose a MAC protocol which achieves better spatial reuse of spectrum thanks to power adjustments based on the number of neighbors in the one-hop neighborhood. Through many simulations we show that our algorithm outperforms the IEEE 802.11 standard, also in high interference environments.

• Dimensioning the Contention Channel of DOCSIS Cable Modem Networks
  J. Lambert, B. Van Houdt & C. Blondia
  Proceedings of Networking 2005, Waterloo, Canada, Lecture Notes in Computer Science, Vol. 3462, pp. 342-357, 2005.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{LambVhBNetw2005,
  author = {J. Lambert and B. Van Houdt and C. Blondia},
  title = {Dimensioning the Contention Channel of DOCSIS Cable Modem Networks},
  booktitle = {Proceedings of Networking 2005},
  series = {Lecture Notes in Computer Science},
  volume = {3462},
  pages = {342--357},
  year = {2005},
  month = {APR},
  location = {Waterloo, Canada},
  URL = {content/publications/2005/LambVhBNetw2005.pdf}
  abstract = {This paper presents an open queueing model with blocking that enables us to
  determine the optimal fraction of the uplink channel capacity that should be dedicated
  to the contention channel in order to minimize the mean response time in a DOCSIS cable
  network. To assess the performance of this queueing network we make use of a decomposition
  technique. One of the key components of the model exists in capturing the behavior of the
  conflict resolution algorithm by means of a single processor sharing queue. The model is
  validated in three successive steps by means of several simulation programs. We also explore
  the impact of a variety of systems parameters, e.g., the number of cable modems, the initial
  backoff window size, etc. , on the optimum.}
  }
  
  Abstract:
  This paper presents an open queueing model with blocking that enables us to the optimal fraction of the uplink channel capacity that should be dedicated the contention channel in order to minimize the mean response time in a DOCSIS cable To assess the performance of this queueing network we make use of a decomposition One of the key components of the model exists in capturing the behavior of the resolution algorithm by means of a single processor sharing queue. The model is in three successive steps by means of several simulation programs. We also explore impact of a variety of systems parameters, e.g., the number of cable modems, the initial window size, etc. , on the optimum.

• Throughput of Q-ary Splitting Algorithms for Contention Resolution in Communication Networks
  B. Van Houdt & C. Blondia
  Communications in Information and Systems, Vol. 4, No. 2, pp. 135-164, 2005.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{total,
  author = {B. Van Houdt and C. Blondia},
  title = {Throughput of Q-ary Splitting Algorithms for Contention Resolution in Communication Networks},
  booktitle = {Communications in Information and Systems},
  volume = {4},
  number = {2},
  pages = {135--164},
  year = {2005},
  month = {MAR},
  URL = {content/publications/2005/total.pdf}
  }
  
  Abstract:
  Not available

• A Reservation Scheme Satisfying Bandwidth QoS Constraints for Ad-Hoc Networks
  L. Cerdà, M. Voorhaen, R. Guimarães, J.M. Barceló, J. García & C. Blondia
  Revised Selected Papers of Wireless Systems and Mobility in Next Generation Internet: First International Workshop of the EURO-NGI Network of Excellence, Dagstuhl Castle, Germany, Lecture Notes in Computer Science, Vol. 3427, pp. 176-188, 2005.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{dagstuhl,
  author = { L. Cerd{\`a} and M. Voorhaen and R. Guimar{\^a}es and J.M. Barcel{\'o} and J. Garc{\'i}a and C. Blondia},
  title = {A Reservation Scheme Satisfying Bandwidth QoS Constraints for Ad-Hoc Networks},
  booktitle = {Revised Selected Papers of Wireless Systems and Mobility in Next Generation Internet: First International Workshop of the EURO-NGI Network of Excellence},
  series = {Lecture Notes in Computer Science},
  volume = {3427},
  pages = {176--188},
  year = {2005},
  month = {FEB},
  location = {Dagstuhl Castle, Germany},
  URL = {content/publications/2005/dagstuhl.pdf},
  abstract = { Achieving QoS (Quality of Service) in Mobile Ad-hoc NETworks (MANET) has been a research topic in the last years. In this paper we describe a QoS reservation mechanism for Routing Ad-hoc Networks. The mechanism is targeted for sources requiring a bandwidth allocation. The mechanism is based on the knowledge of the bandwidth requirements of the neighbors of a node and the interferent nodes in the cover area of each node. We describe as the protocol could be integrated in AODV and OLSR. We also give simulation results showing the advantages of our reservation scheme.}
  }
  
  Abstract:
  Achieving QoS (Quality of Service) in Mobile Ad-hoc NETworks (MANET) has been a research topic in the last years. In this paper we describe a QoS reservation mechanism for Routing Ad-hoc Networks. The mechanism is targeted for sources requiring a bandwidth allocation. The mechanism is based on the knowledge of the bandwidth requirements of the neighbors of a node and the interferent nodes in the cover area of each node. We describe as the protocol could be integrated in AODV and OLSR. We also give simulation results showing the advantages of our reservation scheme.

• Dynamic Bandwidth Allocation for EPON with Threshold Reporting
  D. Nikolova, B. Van Houdt & C. Blondia
  Telecommunication Systems, Vol. 28, No. 1, pp. 31-52, 2005.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{TS2005,
  author = {D. Nikolova, B. Van Houdt and C. Blondia},
  title = {Dynamic Bandwidth Allocation for EPON with Threshold Reporting},
  booktitle = {Telecommunication Systems},
  volume = {28},
  number = {1},
  pages = {31--52},
  year = {2005},
  month = {JAN},
  URL = {content/publications/2005/TS2005.pdf}
  }
  
  Abstract:
  Not available

• Approximated Transient Queue Length and Waiting Time Distributions via Steady State Analysis
  B. Van Houdt & C. Blondia
  Stochastic Models, Vol. 21, No. 2-3, pp. 725-744, 2005.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{SM_transient,
  author = {B. Van Houdt and C. Blondia},
  title = {Approximated Transient Queue Length and Waiting Time Distributions via Steady State Analysis},
  booktitle = {Stochastic Models},
  volume = {21},
  number = {2-3},
  pages = {725--744},
  year = {2005},
  URL = {content/publications/2005/SM_transient.pdf}
  }
  
  Abstract:
  Not available

• Response Time Distribution in a D-MAP/PH/1 Queue with General Customer Impatience
  J. Van Velthoven, B. Van Houdt & C. Blondia
  Stochastic Models, Vol. 21, No. 2-3, pp. 745-765, 2005.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @ARTICLE{SM_impatient,
  author = {J. Van Velthoven and B. Van Houdt and C. Blondia},
  title = {Response Time Distribution in a D-MAP/PH/1 Queue with General Customer Impatience},
  booktitle = {Stochastic Models},
  volume = {21},
  number = {2-3},
  pages = {745--765},
  year = {2005},
  URL = {content/publications/2005/SM_impatient.pdf},
  abstract = {This paper presents two methods to calculate the response time distribution of impatient customers in a discrete-time queue with Markovian arrivals and phase-type services, in which the customers' patience is generally distributed (i.e., the D-MAP/PH/1 queue). The key construction in order to obtain the response time distribution is to set up a GI/M/1-type Markov chain based on the age of the customer being served, together with the state of the D-MAP process immediately after the arrival of this customer. As a by-product, we can also easily obtain the queue length distribution from the steady state of this Markov chain. We consider three different situations: (i) customers leave the system due to impatience regardless of whether they are being served or not, possibly wasting some service capacity, (ii) a customer is only allowed to enter the server if he is able to complete his service before reaching his critical age and (iii) customers become patient as soon as they are allowed to enter the server. In the second part of the paper, we reduce the GI/M/1 type Markov chain to a Quasi-Birth-Death (QBD) process. As a result, the time needed, in general, to calculate the response time distribution is reduced significantly, while only a relatively small amount of additional memory is needed in comparison with the GI/M/1 approach. We also include some numerical examples in which we apply the procedures being discussed.}
  }
  
  Abstract:
  This paper presents two methods to calculate the response time distribution of impatient customers in a discrete-time queue with Markovian arrivals and phase-type services, in which the customers patience is generally distributed (i.e., the D-MAP/PH/1 queue). The key construction in order to obtain the response time distribution is to set up a GI/M/1-type Markov chain based on the age of the customer being served, together with the state of the D-MAP process immediately after the arrival of this customer. As a by-product, we can also easily obtain the queue length distribution from the steady state of this Markov chain. We consider three different situations: (i) customers leave the system due to impatience regardless of whether they are being served or not, possibly wasting some service capacity, (ii) a customer is only allowed to enter the server if he is able to complete his service before reaching his critical age and (iii) customers become patient as soon as they are allowed to enter the server. In the second part of the paper, we reduce the GI/M/1 type Markov chain to a Quasi-Birth-Death (QBD) process. As a result, the time needed, in general, to calculate the response time distribution is reduced significantly, while only a relatively small amount of additional memory is needed in comparison with the GI/M/1 approach. We also include some numerical examples in which we apply the procedures being discussed.

2004

• Quality and performance research on a MPEG video transcoding technique.
  De Neve P., Mertens M., Van Quickenborne F., Moerman I. & Demeester P.
  Accepted at the 11th Symposium on Communications and Vehicular Technology in the Benelux 2004., Gent, Belgium, 2004.
  BibTeX | Abstract
  
  Bibtex:
  @InProceedings{Proceedings of the 11th Symposium on Communications and Vehicular Technology in the Benelux 2004.,
  author = {De Neve P. and Mertens M. and Van Quickenborne F. and Moerman I. and Demeester P.},
  title = {Quality and performance research on a MPEG video transcoding technique.},
  year = {2004},
  month = {November},
  organization = {SCVT },
  booktitle = {Accepted at the 11th Symposium on Communications and Vehicular Technology in the Benelux 2004.},
  location = {Gent, Belgium},
  abstract = {Real-time Mpeg streaming over an IP-based network requires sufficient bandwidth to service all users with a minimal guaranteed quality. If not, video packets will be dropped due to congestion in a fixed network or limited resources in a wireless network, hereby deteriorating the quality substantially. However, in the case of multicasting, an active IP-node, which performs transcoding, could reduce bandwidth requirements and alleviate the load on the video server. However, classical transcoding in real-time requires much processing power. Therefore we propose a new transcoding technique based on the removal of high frequency (high detail) components from the frames of a video sequence. We examined the resulting video quality and the performance of such a trancoding technique}
  }
  
  Abstract:
  Real-time Mpeg streaming over an IP-based network requires sufficient bandwidth to service all users with a minimal guaranteed quality. If not, video packets will be dropped due to congestion in a fixed network or limited resources in a wireless network, hereby deteriorating the quality substantially. However, in the case of multicasting, an active IP-node, which performs transcoding, could reduce bandwidth requirements and alleviate the load on the video server. However, classical transcoding in real-time requires much processing power. Therefore we propose a new transcoding technique based on the removal of high frequency (high detail) components from the frames of a video sequence. We examined the resulting video quality and the performance of such a trancoding technique

• Performance Evaluation of Layer 3 Low Latency Handoff Mechanisms
  C. Blondia, O. Casals, L. Cerdà, N. Van den Wijngaert & G. Willems
  Mobile Networks and Applications, Vol. 9, No. 6, pp. 633-645, 2004.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{monet2004,
  author = {C. Blondia and O. Casals and L. Cerd{\`a} and N. Van den Wijngaert and G. Willems},
  title = {Performance Evaluation of Layer 3 Low Latency Handoff Mechanisms},
  booktitle = {Mobile Networks and Applications},
  volume = {9},
  number = {6},
  pages = {633--645},
  year = {2004},
  month = {DEC},
  URL = {content/publications/2004/monet2004.pdf}
  }
  
  Abstract:
  Not available

• Channel Utilization and Loss Rate in a Single-Wavelength Fibre Delay Line (FDL) Buffer
  B. Van Houdt, K. Laevens, J. Lambert, C. Blondia & H. Bruneel
  Proceedings of IEEE Globecom 2004, paper OC05-07, Dallas, USA, pp. 23-33, 2004.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{GlobeO4,
  author = {B. Van Houdt and K. Laevens and J. Lambert and C. Blondia and H. Bruneel},
  title = {Channel Utilization and Loss Rate in a Single-Wavelength Fibre Delay Line (FDL) Buffer},
  booktitle = {Proceedings of IEEE Globecom 2004, paper OC05-07},
  location = {Dallas, USA},
  pages = {23--33}
  year = {2004},
  month = {NOV},
  URL = {content/publications/2004/Globe04.pdf}
  abstract = {We present a detailed analysis of the maximum
  channel utilization and loss performance in an optical buffer
  having access to a single outgoing channel. As opposed to a
  conventional electronic buffer, such a system - consisting of a
  number of fiber delay lines - can only realize a discrete set
  of delays to resolve output port contention. This leads to an
  underutilization of the channel capacity, which reduces overall
  performance.
  The framework considered in this paper greatly simplifies the
  assumptions made in previous work, which allows us to study
  the impact of a variety of new parameters on the performance,
  e.g., the burstiness of the arrival process and the correlation
  of consecutive burst lengths. Moreover, we present exact results
  for both the channel utilization and loss rate in such a system,
  this in contrast with all prior work which provided accurate
  approximations for the loss rate.
  Matrix analytic methods are used to perform this analysis. To
  the best of our knowledge, this is the first time that such an
  approach is used to analyze an optical buffer. We show, amongst
  others, that carefully choosing the granularity parameter can, in
  some cases, make a substantial difference when trying to realize
  lower buffer losses or a high channel utilization. Optimal values
  of the granularity parameter are shown to be closely related to
  the optical burst length distribution.}
  }
  
  Abstract:
  We present a detailed analysis of the maximum utilization and loss performance in an optical buffer access to a single outgoing channel. As opposed to a electronic buffer, such a system - consisting of a of fiber delay lines - can only realize a discrete set delays to resolve output port contention. This leads to an of the channel capacity, which reduces overall framework considered in this paper greatly simplifies the made in previous work, which allows us to study impact of a variety of new parameters on the performance, the burstiness of the arrival process and the correlation consecutive burst lengths. Moreover, we present exact results both the channel utilization and loss rate in such a system, in contrast with all prior work which provided accurate for the loss rate. analytic methods are used to perform this analysis. To best of our knowledge, this is the first time that such an is used to analyze an optical buffer. We show, amongst that carefully choosing the granularity parameter can, in cases, make a substantial difference when trying to realize buffer losses or a high channel utilization. Optimal values the granularity parameter are shown to be closely related to optical burst length distribution.

• Improving MIP Handover Latency Using Location Information
  N. Van den Wijngaert & C. Blondia
  Information Processing Society of Japan (IPSJ) Journal, Vol. 45, No. 10, pp. 2246-2253, 2004.
  BibTeX
  
  Bibtex:
  @ARTICLE{nvdw04ipsj,
  author = {N. Van den Wijngaert and C. Blondia},
  title = {Improving MIP Handover Latency Using Location Information},
  booktitle = {Information Processing Society of Japan (IPSJ) Journal},
  volume = {45},
  number = {10},
  pages = {2246--2253},
  year = {2004},
  month = {OCT}
  }
  
  Abstract:
  Not available

• Analytical MMAP-Based Bounds for Packet Loss in Optical Packet Switching with Recirculating FDL Buffers
  C. Develder, B. Van Houdt, M. Pickavet, C. Blondia & P. Demeester
  Photonic Network Communications, Vol. 8, No. 2, pp. 149-161, 2004.
  BibTeX
  
  Bibtex:
  @ARTICLE{dev04ana,
  author = {C. Develder and B. Van Houdt and M. Pickavet and C. Blondia and P. Demeester},
  title = {Analytical MMAP-Based Bounds for Packet Loss in Optical Packet Switching with Recirculating FDL Buffers},
  booktitle = {Photonic Network Communications},
  volume = {8},
  number = {2},
  pages = {149--161},
  year = {2004},
  month = {SEP}
  }
  
  Abstract:
  Not available

• A Survey of MAC protocols for Ad Hoc Networks and IEEE 802.11
  Sylwia Romaszko & Chris Blondia
  Proceedings of the 4th National Conference MiSSI 2004, Poland, pp. 23-33, 2004.
  BibTeX | Abstract | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{vdw_onw04_predpost,
  author = {Sylwia Romaszko and Chris Blondia},
  title = {A Survey of MAC protocols for Ad Hoc Networks and IEEE 802.11},
  booktitle = {Proceedings of the 4th National Conference MiSSI 2004},
  location = {Poland},
  pages = {23--33}
  year = {2004},
  month = {SEP},
  abstract = {This article explains limitations of the IEEE 802.11 standard [1] and most of the typical problems in ad hoc networks where the standard is applied. There have been many possible solutions and bservations proposed in many papers. This paper summarizes new techniques and schemes that are not based on the standard. The article is a compendium of knowledge about problems and new approaches in ad hoc networks. It also includes the classification of MAC protocols used in ad hoc networks.},
  URL = {content/publications/2004/Nissi.pdf}
  }
  
  Abstract:
  This article explains limitations of the IEEE 802.11 standard [1] and most of the typical problems in ad hoc networks where the standard is applied. There have been many possible solutions and bservations proposed in many papers. This paper summarizes new techniques and schemes that are not based on the standard. The article is a compendium of knowledge about problems and new approaches in ad hoc networks. It also includes the classification of MAC protocols used in ad hoc networks.

• An Urban Mobility Model and Predictive Handover Scheme for Mobile IP: OPNET Modeling and Simulation
  N. Van den Wijngaert & C. Blondia
  Proceedings of OPNETWORK 2004, Washington DC, USA, 2004.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{vdw_onw04_predpost,
  author = {N. Van den Wijngaert and C. Blondia},
  title = {An Urban Mobility Model and Predictive Handover Scheme for Mobile IP: OPNET Modeling and Simulation},
  booktitle = {Proceedings of OPNETWORK 2004},
  location = {Washington DC, USA},
  year = {2004},
  month = {AUG},
  URL = {content/publications/2004/nvdw_onw04_predpost_final.pdf}
  }
  
  Abstract:
  Not available

• Robustness of Q-ary Collision Resolution Algorithms in Random Access Systems
  B. Van Houdt & C. Blondia
  Performance Evaluation, Vol. 57, No. 3, pp. 357-377, 2004.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{peva1104,
  author = {B. Van Houdt and C. Blondia},
  title = {Robustness of Q-ary Collision Resolution Algorithms in Random Access Systems},
  booktitle = {Performance Evaluation},
  volume = {57},
  number = {3},
  pages = {357--377},
  year = {2004},
  month = {JUL},
  URL = {content/publications/2004/peva1104.pdf}
  }
  
  Abstract:
  Not available

• Implementation and Evaluation of an IEEE802.11 Assisted Mobile IP Handover Scheme
  P. De Cleyn, C. Blondia & I. Moerman
  Proceedings of the 9th European Conference on Networks and Optical Communications (NOC 2004), Session on Mobile Networks, Eindhoven, The Netherlands, pp. 245-252, 2004.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{NOC2004,
  author = {P. De Cleyn and C. Blondia and I. Moerman},
  title = {Implementation and Evaluation of an IEEE802.11 Assisted Mobile IP Handover Scheme},
  booktitle = {Proceedings of the 9th European Conference on Networks and Optical Communications (NOC 2004), Session on Mobile Networks},
  pages = {245--252},
  location = {Eindhoven, The Netherlands},
  year = {2004},
  month = {JUN},
  URL = {content/publications/2004/NOC2004.pdf}
  }
  
  Abstract:
  Not available

• A Smooth Handoff Scheme using IEEE802.11 Triggers - Design and Implementation
  P. De Cleyn, N. Van den Wijngaert, L. Cerdà & C. Blondia
  Computer Networks, Vol. 45, No. 3, pp. 345-361, 2004.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{SmoothHandoff,
  author = {P. De Cleyn and N. Van den Wijngaert and L. Cerd{\`a} and C. Blondia},
  title = {A Smooth Handoff Scheme using IEEE802.11 Triggers - Design and Implementation},
  booktitle = {Computer Networks},
  volume = {45},
  number = {3},
  pages = {345--361},
  year = {2004},
  month = {JUN},
  URL = {content/publications/2004/SmoothHandoff.pdf}
  }
  
  Abstract:
  Not available

• Transient Analysis of the D-BMAP/G/1 Queue with an Application to the Dimensioning of a Playout Buffer for VBR Video
  T. Hofkens, K. Spaey & C. Blondia
  Proceedings of Third International IFIP-TC6 Networking Conference (Networking 2004), Athens, Greece, Lecture Notes in Computer Science, Vol. 3042, pp. 1338-1343, Springer, 2004.
  BibTeX | PDF Available | Technical report (extended version)
  
  Bibtex:
  @INPROCEEDINGS{netw2004,
  author = {T. Hofkens and K. Spaey and C. Blondia},
  title = {Transient Analysis of the D-BMAP/G/1 Queue with an Application to the Dimensioning of a Playout Buffer for VBR Video},
  booktitle = {Proceedings of Third International IFIP-TC6 Networking Conference (Networking 2004)},
  series = {Lecture Notes in Computer Science},
  pages = {1338--1343},
  volume = {3042}
  location = {Athens, Greece},
  year = {2004},
  month = may,
  publisher = {Springer},
  URL = {content/publications/2004/netw2004.pdf},
  techreport = {content/publications/2004/netw2004_ev.pdf}
  }
  
  Abstract:
  Not available

• Optimization of a Packet Video Receiver under Different Levels of Delay Jitter: an Analytical Approach
  N. Laoutaris, B. Van Houdt & I. Stravrakakis
  Performance Evaluation, Yokosuka, Japan, Vol. 55, No. 3-4, pp. 251-257, 2004.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{peva_nikos,
  author = {N. Laoutaris and B. Van Houdt and I. Stravrakakis},
  title = {Optimization of a Packet Video Receiver under Different Levels of Delay Jitter: an Analytical Approach},
  booktitle = {Performance Evaluation},
  volume = {55},
  number = {3-4},
  pages = {251--257},
  location = {Yokosuka, Japan},
  year = {2004},
  month = {FEB},
  URL = {content/publications/2004/peva_nikos.pdf}
  }
  
  Abstract:
  Not available

• A Location Augmented Low Latency Handoff Scheme for Mobile IP
  N. Van den Wijngaert & C. Blondia
  Proceedings of the First International Conference on Mobile Computing and Ubiquitous Networking (ICMU 2004), Yokosuka, Japan, pp. 180-185, 2004.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{ICMU2004-008,
  author = {N. Van den Wijngaert and C. Blondia},
  title = {A Location Augmented Low Latency Handoff Scheme for Mobile IP},
  booktitle = {Proceedings of the First International Conference on Mobile Computing and Ubiquitous Networking (ICMU 2004)},
  pages = {180--185},
  location = {Yokosuka, Japan},
  year = {2004},
  month = {JAN},
  URL = {content/publications/2004/ICMU2004-008.pdf}
  }
  
  Abstract:
  Not available

• On the Sustainable Load of Fibre Delay Line Buffers
  K. Laevens, B. Van Houdt, H. Bruneel & C. Blondia
  IEEE Electronic Letters, Vol. 40, No. 2, pp. 137-138, 2004.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{el04_FDLs,
  author = {K. Laevens and B. Van Houdt and H. Bruneel and C. Blondia},
  title = On the Sustainable Load of Fibre Delay Line Buffers},
  booktitle = {IEEE Electronic Letters},
  volume = {40},
  number = {2},
  pages = {137-138},
  year = {2004},
  month = {JAN},
  URL = {content/publications/2004/el04_FDLs.pdf}
  }
  
  Abstract:
  Not available

• The Waiting Time Distribution of a Type k Customer in a Discrete-Time FCFS MMAP[K]/PH[K]/c (c1,2) Queue using QBDs
  B. Van Houdt & C. Blondia
  Stochastic Models, Vol. 20, No. 1, pp. 55-69, 2004.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{sto04QBD,
  author = {B. Van Houdt and C. Blondia},
  title = {The Waiting Time Distribution of a Type k Customer in a Discrete-Time FCFS MMAP[K]/PH[K]/c (c=1,2) Queue using QBDs},
  booktitle = {Stochastic Models},
  volume = {20},
  number = {1},
  pages = {55-69},
  year = {2004},
  URL = {content/publications/2004/sto04QBD.pdf}
  }
  
  Abstract:
  Not available

2003

• Dynamic Bandwidth Allocation Algorithms in EPON: a Simulation Study
  D. Nikolova, B. Van Houdt & C. Blondia
  Proceedings of Optical Networking and Communications (OptiComm 2003), Dallas, USA, 2003.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{DBA,
  author = {D. Nikolova, B. Van Houdt and C. Blondia},
  title = {Dynamic Bandwidth Allocation Algorithms in EPON: a Simulation Study},
  booktitle = {Proceedings of Optical Networking and Communications (OptiComm 2003)},
  location = {Dallas, USA},
  year = {2003},
  month = {OCT},
  URL = {content/publications/2003/DBA.pdf}
  }
  
  Abstract:
  Not available

• The Delay Distribution of (Im)patient Customers in a Discrete Time DMAP/PH/1 Queue with Age Dependent Service Times
  B. Van Houdt, R.B. Lenin & C. Blondia
  Queueing Systems and its Applications (QUESTA), Vol. 45, No. 1, pp. 59-73, 2003.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{impatient,
  author = {B. Van Houdt and R.B. Lenin and C. Blondia},
  title = {The Delay Distribution of (Im)patient Customers in a Discrete Time DMAP/PH/1 Queue with Age Dependent Service Times},
  booktitle = {Queueing Systems and its Applications (QUESTA)},
  volume = {45},
  number = {1},
  pages = {59--73},
  year = {2003},
  month = {SEP},
  URL = {content/publications/2003/impatient.pdf}
  }
  
  Abstract:
  Not available

• A Location Augmented Low Latency Handoff Scheme for Mobile IP
  N. Van den Wijngaert & C. Blondia
  Proceedings of OPNETWORK 2003, Washington DC, USA, 2003.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{nvdw-opnetwork03-labpr,
  author = {N. Van den Wijngaert and C. Blondia},
  title = {A Location Augmented Low Latency Handoff Scheme for Mobile IP},
  booktitle = {Proceedings of OPNETWORK 2003},
  location = {Washington DC, USA},
  year = {2003},
  month = {AUG},
  URL = {content/publications/2003/nvdw-opnetwork03-labpr-final.pdf}
  }
  
  Abstract:
  Not available

• QoS Issues in EPON
  D. Nikolova, B. Van Houdt & C. Blondia
  Proceedings of Community Nets and FTTH/P/x Workshop, Dallas, USA, 2003.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{QoSinEPON,
  author = {D. Nikolova and B. Van Houdt and C. Blondia},
  title = {QoS Issues in EPON},
  booktitle = {Proceedings of Community Nets and FTTH/P/x Workshop},
  location = {Dallas, USA},
  year = {2003},
  month = {OCT},
  URL = {content/publications/2003/QoSinEPON.pdf}
  }
  
  Abstract:
  Not available

• Low Latency Handoff Mechanisms and Their Implementation in an IEEE 802.11 Network
  C. Blondia, O. Casals, L. Cerda, N. Van den Wijngaert, G. Willems & P. De Cleyn
  Proceedings of ITC18: Providing Quality of Service in Heterogeneous Environments, Berlin, Germany, Teletraffic and Engineering, Vol. 5b, pp. 971-980, 2003.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{paper63,
  author = { C. Blondia and O. Casals and L. Cerda and N. Van den Wijngaert and G. Willems and P. De Cleyn},
  title = {Low Latency Handoff Mechanisms and Their Implementation in an IEEE 802.11 Network},
  booktitle = {Proceedings of ITC18: Providing Quality of Service in Heterogeneous Environments},
  series = {Teletraffic and Engineering},
  volume = {5b},
  pages = {971--980},
  location = {Berlin, Germany},
  year = {2003},
  URL = {content/publications/2003/paper63.pdf}
  }
  
  Abstract:
  Not available

• Tree Structured QBD Markov chains and Tree-Like QBD Processes
  B. Van Houdt & C. Blondia
  Stochastic Models, Vol. 19, No. 4, 2003.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{treelike,
  author = {B. Van Houdt and C. Blondia},
  title = {Tree Structured QBD Markov chains and Tree-Like QBD Processes},
  booktitle = {Stochastic Models},
  volume = {19},
  number = {4},
  year = {2003},
  URL = {content/publications/2003/treelike.pdf}
  }
  
  Abstract:
  Not available

• Maximum Stable Throughput of FS-ALOHA under Delay Constraints
  B. Van Houdt & C. Blondia
  Proceedings of ITC18: Providing Quality of Service in Heterogeneous Environments, Berlin, Germany, Teletraffic and Engineering, Vol. 5b, pp. 941-950, 2003.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{itc03fsaloha,
  author = {B. Van Houdt and C. Blondia},
  title = {Maximum Stable Throughput of FS-ALOHA under Delay Constraints},
  booktitle = {Proceedings of ITC18: Providing Quality of Service in Heterogeneous Environments},
  series = {Teletraffic and Engineering},
  volume = {5b},
  pages = {941--950},
  location = {Berlin, Germany},
  year = {2003},
  URL = {content/publications/2003/itc03fsaloha.pdf}
  }
  
  Abstract:
  Not available

• Timescales in Models for Bursty Traffic
  K. Spaey, D. De Vleeschauwer, T. Hofkens & C. Blondia
  Proceedings of the 2003 International Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS 2003), Montreal, Canada, Simulation Series, Vol. 35, No. 4, pp. 465-473, 2003.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{timescales,
  author = {K. Spaey and D. De Vleeschauwer and T. Hofkens and C. Blondia},
  title = {Timescales in Models for Bursty Traffic},
  pages = {465--473},
  booktitle = {Proceedings of the 2003 International Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS 2003)},
  location = {Montreal, Canada},
  year = {2003},
  month = jul,
  series = {Simulation Series},
  volume = {35},
  number = {4},
  URL = {content/publications/2003/timescales.pdf}
  }
  
  Abstract:
  Not available

• Bandwidth versus Storage Trade-off in a Content Distribution Network and a Single Server System
  S. Van Rompaey, K. Spaey & C. Blondia
  Proceedings of the 7th International Conference on Telecommunications (ConTEL 2003), Zagreb, Croatia, pp. 315-320, 2003.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{bandwidth_storage,
  author = {S. Van Rompaey and K. Spaey and C. Blondia},
  title = {Bandwidth versus Storage Trade-off in a Content Distribution Network and a Single Server System},
  booktitle = {Proceedings of the 7th International Conference on Telecommunications (ConTEL 2003)},
  pages = {315--320},
  location = {Zagreb, Croatia},
  year = {2003},
  month = jun,
  vol = {1 of 2},
  URL = {content/publications/2003/bandwidth_storage.pdf}
  }
  
  Abstract:
  Not available

• Performance Comparison of Low Latency Mobile IP Schemens
  C. Blondia, O. Casals, L. Cerda, N. Van den Wijngaert, G. Willems & P. De Cleyn
  Proceedings of WiOpt 03: Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks, INRIA, Sophia Antipolis, pp. 115-124, 2003.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{WiOpt03,
  author = {C. Blondia and O. Casals and L. Cerda and N. Van den Wijngaert and G. Willems and P. De Cleyn},
  title = {Performance Comparison of Low Latency Mobile IP Schemens},
  booktitle = {Proceedings of WiOpt `03: Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks},
  location = {INRIA, Sophia Antipolis},
  year = {2003},
  month = {MAR},
  pages = {115--124},
  URL = {content/publications/2003/WiOpt03_final.pdf}
  }
  
  Abstract:
  Not available

• Performance Evaluation of the Post-Registration Method, a Low Latency Handoff in MIPv4
  O. Casals, L. Cerda, G. Willems, C.Blondia & N. Van den Wijngaert
  Proceedings of IEEE 2003 International Confernence on Communications (ICC 2003), Anchorage, 2003.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{icc03_fin,
  author = {O. Casals and L. Cerda and G. Willems and C.Blondia and N. Van den Wijngaert},
  title = {Performance Evaluation of the Post-Registration Method, a Low Latency Handoff in MIPv4},
  booktitle = { Proceedings of IEEE 2003 International Confernence on Communications (ICC 2003)},
  location = {Anchorage},
  year = {2003},
  month = {MAY}
  URL = {content/publications/2003/icc03_fin.pdf}
  }
  
  Abstract:
  Not available

• Robustness properties of FS-ALOHA(++): a contention resolution algorithm for dynamic bandwidth allocation
  B. Van Houdt & C. Blondia
  Mobile Networks and Applications (MONET), Special Issue on Performance Evaluation of QoS Architectures in Mobile Networks, Vol. 8, No. 3, pp. 237-253, 2003.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE {MONET,
  author = {B. Van Houdt and C. Blondia},
  title = {Robustness properties of FS-ALOHA(++): a contention resolution algorithm for dynamic bandwidth allocation},
  booktitle = { Mobile Networks and Applications (MONET), Special Issue on Performance Evaluation of QoS Architectures in Mobile Networks},
  volume = {8}
  number = {3}
  pages = {237--253}
  year = {2003},
  URL = {content/publications/2003/MONET.pdf}
  }
  
  Abstract:
  Not available

2002

• Study and demonstration of extensions to the standard FSAN BPON
  P. Vetter, F. Fredricx, E. Ringoot, N. Janssens, B. De Vos, C. Bouchat, F. Duthilleul, C. Dessauvages, B. Stubbe, E. Gilon, M. Tassent, X.Z. Qiu, J. Vandewege, P. Ossieur, J. Bauwelinck, J. Watte & C. Blondia
  Proceedings of ISSLS 2002, Seoul, 2002.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{issls2002,
  author = {P. Vetter and F. Fredricx and E. Ringoot and N. Janssens and B. De Vos and C. Bouchat and F. Duthilleul and C. Dessauvages and B. Stubbe and E. Gilon and M. Tassent and X.Z. Qiu and J. Vandewege and P. Ossieur and J. Bauwelinck and J. Watte and C. Blondia},
  title = {Study and demonstration of extensions to the standard FSAN BPON},
  booktitle = {Proceedings of ISSLS 2002},
  location = {Seoul},
  year = {2002},
  month= {APR},
  URL = {content/publications/2002/issls2002.pdf}
  }
  
  Abstract:
  Not available

• Computing packet loss probabilities in multiplexer models using rational approximation
  A. Cuyt, R.B. Lenin, G. Willems, C. Blondia & P. Rousseeuw
  IEEE Transactions on Computers, Canada, Vol. 52, No. 5, pp. 1-12, 2002.
  TODO: 2002 or 2003 ????? en paper is toch geen short name
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE{paper,
  author = {A. Cuyt and R.B. Lenin and G. Willems and C. Blondia and P. Rousseeuw},
  title = {Computing packet loss probabilities in multiplexer models using rational approximation},
  booktitle = {IEEE Transactions on Computers},
  location = {Canada},
  volume = {52},
  number = {5}
  pages = {1--12},
  year = {2002},
  month= {MAY},
  URL = {content/publications/2002/paper.pdf}
  note = {TODO: 2002 or 2003 ????? en paper is toch geen short name}
  }
  
  Abstract:
  Not available

• Performance of Telecommunication systems: selected topics
  K. Kostovasilis, S. Wittewrongel, H. Bruneel, B. Van Houdt & C. Blondia
  Proceedings of IFIP World Congres, Canada, pp. 61-93, 2002.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{kimon,
  author = {K. Kostovasilis and S. Wittewrongel and H. Bruneel and B. Van Houdt and C. Blondia},
  title = {Performance of Telecommunication systems: selected topics},
  booktitle = {Proceedings of IFIP World Congres},
  location = {Canada},
  pages = {61--93},
  year = {2002},
  month= {AUG},
  URL = {content/publications/2002/kimon.pdf}
  }
  
  Abstract:
  Not available

• Performance Analysis of Optimized Smooth Handoff in Mobile IP
  C. Blondia, N. Van den Wijngaert, G. Willems & O. Casals
  Proceedings of the 5th ACM International workshop on Modeling, Analysis and Simulation of Wireless and Mobile Systems, Atlanta, pp. 22-29, 2002.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{p74-blondia,
  author = {C. Blondia, N. Van den Wijngaert, G. Willems, O. Casals},
  title = {Performance Analysis of Optimized Smooth Handoff in Mobile IP},
  booktitle = { Proceedings of the 5th ACM International workshop on Modeling, Analysis and Simulation of Wireless and Mobile Systems},
  location = {Atlanta},
  pages = {22--29},
  year = {2002},
  month = {SEP},
  URL = {content/publications/2002/p74-blondia.pdf}
  }
  
  Abstract:
  Not available

• Mobile Extranet Based Integrated User Services (MOEBIUS)
  C. Blondia, O. Casals, A. Dyson & E. Monticelli
  Proceedings of IST Mobile and Wireless Telecommunications Summit 2002, Thesaloniki, pp. 758-763, 2002.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{IST-summit02,
  author = {C. Blondia and O. Casals and A. Dyson and E. Monticelli},
  title = {Mobile Extranet Based Integrated User Services (MOEBIUS)},
  booktitle = {Proceedings of IST Mobile and Wireless Telecommunications Summit 2002},
  location = {Thesaloniki},
  pages = {758--763},
  year = {2002},
  month = {JUN},
  URL = {content/publications/2002/IST-summit02.pdf}
  }
  
  Abstract:
  Not available

• Integration of IP Mobility in OPNET: Modeling and simulation
  N. Van den Wijngaert & C. Blondia
  Proceedings of OPNETWORK2002, Washington, D.C., 2002.
  BibTeX | PDF Available
  
  Bibtex:
  @INPROCEEDINGS{opnetwork-mip,
  author = {N. Van den Wijngaert and C. Blondia},
  title = {Integration of IP Mobility in OPNET: Modeling and simulation},
  booktitle = {Proceedings of OPNETWORK2002},
  location = {Washington, D.C.},
  year = {2002},
  month = {AUG},
  URL = {content/publications/2002/opnetwork-mip.pdf}
  }
  
  Abstract:
  Not available

• The delay distribution of a type K customer in a FCFS MMAP[K]/PH[K]/1 queue
  B. Van Houdt & C. Blondia
  Journal of Applied Probability (JAP), Vol. 39, No. 1, 2002.
  BibTeX | PDF Available
  
  Bibtex:
  @ARTICLE {JAP,
  author = {B. Van Houdt and C. Blondia},
  title = {The delay distribution of a type K customer in a FCFS MMAP[K]/PH[K]/1 queue},
  booktitle = {Journal of Applied Probability (JAP)},
  year = {2002},
  volume = {39},
  number = {1},
  URL = {content/publications/2002/JAP.pdf}
  }
  
  Abstract:
  Not available