This file was created by the TYPO3 extension bib --- Timezone: UTC Creation date: 2025-03-31 Creation time: 22-56-01 --- Number of references 32 article 2014-alizai-pad-jnca Elsevier Journal of Network and Computer Applications (JNCA) 2014 unpublished en 1 Muhammad HamadAlizai KlausWehrle article 2013-elsevir-aktas-harnessing-cross-layer-design Elsevir Ad-hoc Networks 2013 10 1 crawler 1 IsmetAktas Muhammad HamadAlizai FlorianSchmidt HannoWirtz KlausWehrle article 2013-wirtz-alizai-tinywifi-jnca Journal of Network and Computer Applications (JNCA) 2013 Co-primary authorship Alizai, Wirtz fileadmin/papers/2013/2013-wirtz-alizai-tinywifi-jnca.pdf http://www.sciencedirect.com/science/article/pii/S108480451300060X en 1084-8045 10.1016/j.jnca.2013.02.022 1 HannoWirtz Muhammad HamadAlizai BernhardKirchen KlausWehrle article 2012-4-alizai-wild-ijdsn International Journal of Distributed Sensor Networks (IJDSN) 2012 4 2 wld fileadmin/papers/2012/2012-ijdsn-wld-alizai.pdf unpublished en 1550-1329 1 Muhammad HamadAlizai OlafLandsiedel KlausWehrle article 2009AlizaiPIKtimingenergy PIK Journal, Special Issue on Energy Aware Systems 2009 2 32 2 127-132 fileadmin/papers/2009/2009-2-alizai-modeling-energy.pdf Print en 0930-5157 1 Muhammad HamadAlizai OlafLandsiedel KlausWehrle inbook 2010-02-book-alizai-hardware-and-systems 2010 2 1 99-117 http://www.network-simulation.info/ http://www.amazon.com/Modeling-Tools-Network-Simulation-Wehrle/dp/3642123309 Print Springer LNCS Chapter 7 Modeling and Tools for Network Simulation EN 978-3-642-12330-6 Muhammad HamadAlizai LeiGao TorstenKempf OlafLandsiedel inproceedings 2024-buildsys-breyer-waterreview 2024 11 6 318-322 www.comsys.rwth-aachen.de/fileadmin/papers/2024/2024-breyer-waterreview.pdf Online ACM Proceedings of the 11th ACM International Conference on Systems for Energy-Efficient Buildings, Cities, and Transportation (BuildSys 2024), Hangzhou, China en 979-8-4007-0706-3/24/11 10.1145/3671127.3698793 1 JustusBreyer MaximilianPetri Muhammad HamadAlizai KlausWehrle inproceedings 2024-buildsys-breyer-transferstudy 2024 11 6 333-336 www.comsys.rwth-aachen.de/fileadmin/papers/2024/2024-breyer-transferstudy.pdf Online ACM Proceedings of the 11th ACM International Conference on Systems for Energy-Efficient Buildings, Cities, and Transportation (BuildSys 2024), Hangzhou, China en 979-8-4007-0706-3/24/11 10.1145/3671127.3699532 1 JustusBreyer SparshJauhari RenéGlebke Muhammad HamadAlizai MarkusStroot KlausWehrle inproceedings 2016-ahmed-sensys-poster-incremental 2016 11 14 1--2 We propose incremental checkpointing techniques enabling transiently powered devices to retain computational state across multiple activation cycles. As opposed to the existing approaches, which checkpoint complete program state, the proposed techniques keep track of modified RAM locations to incrementally update the retained state in secondary memory, significantly reducing checkpointing overhead both in terms of time and energy. /fileadmin/misc/2016/2016-ahmed-sensys-poster-incremental.pdf http://dl.acm.org/citation.cfm?id=2996701 2016-11-20 http://sensys.acm.org/2016/ Online ACM Proceedings of the 14th ACM Conference on Embedded Networked Sensor Systems (SenSys 2016), Stanford, CA, USA Stanford, CA, USA Sensys '16 November 14-16, 2016 en 978-1-4503-4263-6/16/11 http://dx.doi.org/10.1145/2994551.2996701 1 SaadAhmed HassanKhan Junaid HaroonSiddiqui Jó AgilaBitsch Link Muhammad HamadAlizai inproceedings 2014-comsnets-aktas-graph-based-redundancy-removal 2014 1 7 1-8 crawler http://www.comsys.rwth-aachen.de/fileadmin/papers/2014/2014-aktas-comsnets-redundancy.pdf Online IEEE Proceedings of the 2014 Sixth International Conference on Communication Systems and Networks (COMSNETS), Bangalore, India Bangalore, India 2014 Sixth International Conference on Communication Systems and Networks (COMSNETS) 7-10 January, 2014 en 978-1-4799-3635-9 10.1109/COMSNETS.2014.6734899 1 IsmetAktas MartinHenze Muhammad HamadAlizai KevinMöllering KlausWehrle inproceedings 2013-wons-wirtz-fuzzy 2013 3 Online IEEE Proceedings of the 10th International Conference on Wireless On-demand Network Systems and Services (WONS '13), Banff, Canada Banff, Canada en 978-1-4799-0747-2 10.1109/WONS.2013.6578338 1 HannoWirtz Muhammad HamadAlizai KlausWehrle inproceedings 2012-aktas-wowmom-CRAWLER:AnExperimentationPlatformforSystemMonitoringandCross-Layer-Coordination-conference Proceedings of the 13th International Symposium on a World of Wireless, Mobile and MultimediaNetworks (WoWMoM'12), San Francisco, USA 2012 6 25 1--9 crawler fileadmin/papers/2012/2012-aktas-wowmom-crawler.pdf Online IEEE Proceedings of the 13th International Symposium on a World of Wireless, Mobile and MultimediaNetworks (WoWMoM'12), San Francisco, USA San Francisco 13th International Symposium on a World of Wireless, Mobile and MultimediaNetworks (WoWMoM'12) 25-28 June, 2012 en 978-1-4673-1238-7 10.1109/WoWMoM.2012.6263686 1 IsmetAktas FlorianSchmidt Muhammad HamadAlizai TobiasDrüner KlausWehrle inproceedings 2011-12-conext-schmidt-refector 2011 12 6 1--12 refector fileadmin/papers/2011/2011-schmidt-refector-conext.pdf Online ACM

New York, NY, USA

Proceedings of the 7th International Conference on emerging Networking EXperiments and Technologies (CoNEXT), Tokyo, Japan Tokyo, Japan 7th ACM International Conference on emerging Networking EXperiments and Technologies (CoNEXT) 6-9 December, 2011 en 978-1-4503-1041-3 10.1145/2079296.2079318 1 FlorianSchmidt Muhammad HamadAlizai IsmetAktas KlausWehrle inproceedings VaegsABW2011 2011 9 16 77-80 A tremendous amount of energy is wasted today, because computing devices are left running all the time even though they are needed only sporadically. Especially in office environments many devices (e.g., printers) are very rarely turned off, because they need to be available from time to time and because it is inconvenient having to switch them on and off manually. Existing solutions, such as Wake-on-LAN (WoL), provide support for managing the power consumption of the network devices remotely using an always-on data channel. However, these solutions are inefficient, because power to the network interface has to be maintained even when the host system is asleep just to ensure remote accessibility. We propose a Wireless Sensor Network (WSN) based out-of-band signaling architecture for network interfaces which minimizes the systems’ power consumption during the large idle periods when nobody is using them. This is done by separating the data and control channels on the Internet-enabled devices using a low-power out-of-band signaling channel based on battery driven, energy scavenging devices. Unlike existing solutions, which only allow parts of the system to go in sleep modes, our architecture allows the whole system, including the main power supply, to be shut down. Our initial investigation indicates a significant reduction in energy consumption of devices during idle times compared to the existing in-band signaling mechanisms such as WoL. Energy Saving, Wireless Sensor Network, Out-of-Band Signalling https://www.comsys.rwth-aachen.de/fileadmin/papers/2011/2011-vaegs-fgsn-ecocom.pdf Online Proceedings of the 10th GI/ITG KuVS Fachgespräch Drahtlose Sensornetze (FGSN), Paderborn, Germany RWTH Aachen University Paderborn, Germany 10th GI/ITG KuVS Fachgespräch Drahtlose Sensornetze (FGSN11) September 15-16, 2011 en 1 TobiasVaegs Muhammad HamadAlizai Jó AgilaBitsch Link KlausWehrle inproceedings 2011-wintech-alizai-tinywifi 2011 9 19-27 tinywifi fileadmin/papers/2011/2010-09-tinywifi-alizai-wintech.pdf Online ACM

New York, NY, USA

Proceedings of the Sixth ACM International Workshop on Wireless Network Testbeds, Experimental evaluation and Characterization (WiNTECH ), Las Vegas, NV, USA Las Vegas, NV, USA The 17th Annual International Conference on Mobile Computing and Networking September 2011 en 978-1-4503-0867-0 10.1145/2030718.2030725 1 Muhammad HamadAlizai HannoWirtz BernhardKirchen TobiasVaegs OmprakashGnawali KlausWehrle inproceedings 2011-iscc-alizai-ble 2011 6 fileadmin/papers/2011/2011-alizai-iscc-ble.pdf Online IEEE Computer Society

Los Alamitos, CA, USA

16th IEEE Symposium on Computers and Communications (ISCC), Kerkyra, Greece Kerkyra, Greece en 978-1-4577-0678-3 10.1109/ISCC.2011.5983839 1 Muhammad HamadAlizai HannoWirtz GeorgKunz BenjaminGrap KlausWehrle inproceedings 2011-ipsn-alizai-pad 2011 4 fileadmin/papers/2011/2011-ipsn-alizai-pad.pdf Online ACM

New York, NY, USA

Proceedings of the 10th ACM/IEEE International Conference on Information Processing in Sensor Networks (IPSN 2011), Chicago, IL, USA Chicago, IL, USA en 978-1-60558-988-6 1 Muhammad HamadAlizai TobiasVaegs OlafLandsiedel StefanGötz Jó AgilaBitsch Link KlausWehrle inproceedings 2010-sensys-alizai-tinywifi 2010 11 429-430 We present TinyWifi, a nesC code base extending TinyOS to support Linux powered network nodes. It enables developers to build arbitrary TinyOS applications and protocols and execute them directly on Linux by compiling for the new TinyWifi platform. Using TinyWifi as a TinyOS platform, we expand the applicability and means of evaluation of wireless protocols originally designed for sensornets towards inherently similar Linux driven ad hoc and mesh networks. Received Best Poster Award fileadmin/papers/2010/2010-11-alizai-tinywifi-sensys.pdf http://portal.acm.org/citation.cfm?id=1870058&preflayout=flat Print ACM

New York, NY, USA

Proceedings of the 8th ACM Conference on Embedded Networked Sensor Systems (SenSys 2010), Zurich, Switzerland en 978-1-4503-0344-6 10.1145/1869983.1870058 1 Muhammad HamadAlizai BernhardKirchen Jó AgilaBitsch Link HannoWirtz KlausWehrle inproceedings 201004vaegsieeestudentpad 2010 5 20 5-8 The lack of permanent network infrastructure and often unplanned deployments in many multihop wireless communication scenarios restrict nodes to determine their own addresses based on the underlying connectivity in the network. However, due to unreliable connectivity and rapidly changing link qualities in wireless networks, establishing uniform addressing and stable point-to-point routing is challenging. In this paper, we present Statistical Vector Routing (SVR), a virtual coordinates based addressing and routing mechanism that efficiently deals with dynamic communication links in wireless networks. It assigns stable probabilistic addresses to nodes without the need to pessimistically estimate links over longer periods of time. The routing metric predicts the current location of a node in its address distribution. Our prototype implementation over real testbeds indicates that SVR, when compared to current approaches, achieves 3 times more stable addressing, reduces the magnitude of change in addresses by 2-10 times, and minimizes the hop distance and transmissions in the network by 10-15%. wld https://www.comsys.rwth-aachen.de/fileadmin/papers/2010/2010-vaegs-wehrle-probabilistic_addressing.pdf Print Hamburg University of Technology

Hamburg, Germany

Proceedings of the 2nd IEEE Student Conference, Hamburg University of Technology, Hamburg, Germany Hamburg, Germany 2nd IEEE Student Conference, Hamburg University of Technology May 20-21, 2010 en TobiasVaegs Muhammad HamadAlizai KlausWehrle inproceedings 2010-ipsn-sasnauskas-kleenet 2010 4 12 186--196 Complex interactions and the distributed nature of wireless sensor networks make automated testing and debugging before deployment a necessity. A main challenge is to detect bugs that occur due to non-deterministic events, such as node reboots or packet duplicates. Often, these events have the potential to drive a sensor network and its applications into corner-case situations, exhibiting bugs that are hard to detect using existing testing and debugging techniques. In this paper, we present KleeNet, a debugging environment that effectively discovers such bugs before deployment. KleeNet executes unmodified sensor network applications on symbolic input and automatically injects non-deterministic failures. As a result, KleeNet generates distributed execution paths at high-coverage, including low-probability corner-case situations. As a case study, we integrated KleeNet into the Contiki OS and show its effectiveness by detecting four insidious bugs in the uIP TCP/IP protocol stack. One of these bugs is critical and lead to refusal of further connections. automated protocol testing, experimentation, failure detection, wireless sensor networks kleenet fileadmin/papers/2010/2010-04-ipsn-sasnauskas-KleeNet.pdf Print ACM

New York, NY, USA

Proceedings of the 9th ACM/IEEE International Conference on Information Processing in Sensor Networks (IPSN 2010), Stockholm, Sweden en 978-1-60558-988-6 http://doi.acm.org/10.1145/1791212.1791235 1 RaimondasSasnauskas OlafLandsiedel Muhammad HamadAlizai CarstenWeise StefanKowalewski KlausWehrle inproceedings 20104-IPSN-alizai-svr 2010 4 12 366-367 We present Statistical Vector Routing (SVR), a protocol that efficiently deals with communication link dynamics in wireless networks. It assigns virtual coordinates to nodes based on the statistical distribution of their distance from a small set of beacons. The distance metric predicts the current location of a node in its address distribution. Our initial results from a prototype implementation over real testbeds demonstrate the feasibility of SVR. wld https://www.comsys.rwth-aachen.de/fileadmin/papers/2010/2010-alizai-ipsn-pad.pdf http://portal.acm.org/citation.cfm?id=1791257 Print ACM

New York, NY, USA

Proceedings of the 9th ACM/IEEE International Conference on Information Processing in Sensor Networks (IPSN 2010), Stockholm, Sweden Stockholm, Sweden 9th ACM/IEEE International Conference on Information Processing in Sensor Networks (IPSN 2010) April 12-16, 2010 en 978-1-60558-988-6 1 Muhammad HamadAlizai TobiasVaegs OlafLandsiedel RaimondasSasnauskas KlausWehrle inproceedings 2010-bitsch-link-iq2s-burrowview 2010 3 29 56 -- 61 For a long time, life sciences were restricted to look at animal habitats only post-factum. Pervasive computing puts us in the novel position to gain live views. In this paper we present BurrowView, an application that tracks the movement of rats in their natural habitat and reconstructs the underground tunnel system. To make reliable statements, special consideration has been taken with regard to the information quality. Our system is able to reconstruct paths up to a resolution of 20 cm, the length of a rat without its tail. RatPack fileadmin/papers/2010/2010-03-IQ2S-link-burrowview.pdf http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=5470603 Online IEEE

New York City, NY, USA

Proceedings of the Second IEEE International Workshop on Information Quality and Quality of Service for Pervasive Computing (IQ2S 2010), Mannheim, Germany IEEE Mannheim, Germany Second IEEE International Workshop on Information Quality and Quality of Service for Pervasive Computing (IQ2S 2010) March 29 to April 2, 2010 en 978-1-4244-6605-4 10.1109/PERCOMW.2010.5470603 1 Jó AgilaBitsch Link GregorFabritius Muhammad HamadAlizai KlausWehrle inproceedings 20105munawardynamictinyos 2010 1-6 Long-term deployments of sensor networks in physically inaccessible environments make remote re-programmability of sensor nodes a necessity. Ranging from full image replacement to virtual machines, a variety of mechanisms exist today to deploy new software or to fix bugs in deployed systems. However, TinyOS - the current state of the art sensor node operating system - is still limited to full image replacement as nodes execute a statically-linked system-image generated at compilation time. In this paper we introduce Dynamic TinyOS to enable the dynamic exchange of software components and thus incrementally update the operating system and its applications. The core idea is to preserve the modularity of TinyOS, i.e. its componentization, which is lost during the normal compilation process, and enable runtime composition of TinyOS components on the sensor node. The proposed solution integrates seamlessly into the system architecture of TinyOS: It does not require any changes to the programming model of TinyOS and existing components can be reused transparently. Our evaluation shows that Dynamic TinyOS incurs a low performance overhead while keeping a smaller - upto one third - memory footprint than other comparable solutions. fileadmin/papers/2010/2010-05-icc-munawar-DynamicTinyOS.pdf Online IEEE Proceedings of the IEEE International Conference on Communications (ICC), Cape Town, South Africa en 978-1-4244-6402-9 1550-3607 1 WaqaasMunawar Muhammad HamadAlizai OlafLandsiedel KlausWehrle inproceedings 2010-ARCS-alizai-promotingpower 2010 387-392 Accurate prediction of energy consumption early in the design process is essential to efficiently optimize algorithms and protocols. However, despite energy efficiency gathering significant attention in networking research, limited effort has been invested in providing requisite evaluation tools and models. Hence, developers demand powerful evaluation tools to assist them in comparing new communication paradigms in terms of energy efficiency, and minimizing the energy requirements of algorithms. In this paper, we argue for promoting energy to a first class metric in network simulations. We explore the challenges involved in modelling energy in network simulations and present a detailed analysis of different modelling techniques. Finally, we discuss their applicability in high-level network simulations. fileadmin/papers/2010/2010-2-ARCS-alizai-promoting-power.pdf Print VDE-VERLAG

Berlin, Germany

Proceedings of the Workshop on Energy Aware Systems and Methods, in conjunction with GI/ITG ARCS 2010 Hannover, Feb. 21-23 en 978-3-8007-3222-7 1 Muhammad HamadAlizai GeorgKunz OlafLandsiedel KlausWehrle inproceedings 2009-sensys-alizai-burstytraffic 2009 11 71-84 wld fileadmin/papers/2009/2009-alizai-sensys-bre.pdf ACM

New York, NY, USA

Proceeding of 7th ACM Conference on Embedded Networked Sensor Systems (Sensys 09), Berkeley, CA, USA Berkley, California Sensys 09 November 2009 en 978-1-60558-519-2 1 Muhammad HamadAlizai OlafLandsiedel Jó AgilaBitsch Link StefanGötz KlausWehrle inproceedings 2008-sensys-sasnauskas-kleenet 2008 11 425--426 We present KleeNet, a Klee based bug hunting tool for sensor network applications before deployment. KleeNet automatically tests code for all possible inputs, ensures memory safety, and integrates well into TinyOS based application development life cycle, making it easy for developers to test their applications. bug finding, memory safety, tinyos, type safety kleenet fileadmin/papers/2008/2008-11-Sasnauskas-SenSys08-KleeNet.pdf Print ACM

New York, NY, USA

Proceedings of the 6th ACM conference on Embedded network sensor systems (SenSys'08), Raleigh, NC, USA en 978-1-59593-990-6 http://doi.acm.org/10.1145/1460412.1460485 1 RaimondasSasnauskas Jó AgilaBitsch Link Muhammad HamadAlizai KlausWehrle inproceedings 200804landsiedelIPSN08TimingMatters 2008 344-354 The rising complexity of data processing algorithms in sensor networks combined with their severely limited computing power necessitates an in-depth understanding of their temporal behavior. However, today only cycle accurate emulation and test-beds provide a detailed and accurate insight into the temporal behavior of sensor networks. In this paper we introduce fine grained, automated instrumentation of simulation models with cycle counts derived from sensor nodes and application binaries to provide detailed timing information. The presented approach bridges the gap between scalable but abstracting simulation and cycle accurate emulation for sensor network evaluation. By mapping device-specific code with simulation models, we can derive the time and duration a certain code line takes to get executed on a sensor node. Hence, eliminating the need to use expensive instruction-level emulators with limited speed and restricted scalability. Furthermore, the proposed design is not bound to a specific hardware platform, a major advantage compared to existing emulators. Our evaluation shows that the proposed technique achieves a timing accuracy of 99% compared to emulation while adding only a small overhead. Concluding, it combines essential properties like accuracy, speed and scalability on a single simulation platform. fileadmin/papers/2008/2008-04-IPSN-2008-landsiedel-Timing-Matters.pdf Print IEEE Computer Society

Washington, DC, USA

Proceedings of the 7th ACM International Conference on Information Processing in Sensor Networks (IPSN 2008), St. Louis, MO, USA en 978-0-7695-3157-1 1 OlafLandsiedel Muhammad HamadAlizai KlausWehrle techreport 200908munawarfgsndynamictinyos 2009 9 9-12 fileadmin/papers/2009/2009-08-munawar-fgsn-dynamic-tinyos.pdf http://doku.b.tu-harburg.de/volltexte/2009/581/pdf/proceedings.pdf Print Technical University Hamburg

Technical University Hamburg

Proceedings of the 8th GI/ITG KuVS Fachgespräch "Wireless Sensor Networks", Hamburg, Germany Technical University Hamburg en WaqaasMunawar OlafLandsiedel Muhammad HamadAlizai KlausWehrle techreport 200908alizaifgsnburstyrouting 2009 9 63-66 Accurate estimation of link quality is the key to enable efficient routing in wireless sensor networks. Current link estimators focus mainly on identifying long-term stable links for routing, leaving out a potentiality large set of intermediate links offering significant routing progress. Fine-grained analysis of link qualities reveals that such intermediate links are bursty, i.e., stable in the short term. In this paper, we use short-term estimation of wireless links to accurately identify short-term stable periods of transmission on bursty links. Our approach allows a routing protocol to forward packets over bursty links if they offer better routing progress than long-term stable links. We integrate a Short Term Link Estimator and its associated routing strategy with a standard routing protocol for sensor networks. Our evaluation reveals an average of 22% reduction in the overall transmissions when routing over long-range bursty links. Our approach is not tied to any special routing protocol and integrates seamlessly with existing routing protocols and link estimators. wld fileadmin/papers/2009/2009-08-alizai-fgsn-bursty-routing.pdf doku.b.tu-harburg.de/volltexte/2009/581/pdf/proceedings.pdf Print Technical University Hamburg

Technical University Hamburg

Proceedings of the 8th GI/ITG KuVS Fachgespräch "Wireless Sensor Networks", Hamburg, Germany en 1 Muhammad HamadAlizai OlafLandsiedel Jó AgilaBitsch Link StefanGötz KlausWehrle techreport 2008-fgsn-sasnauskas-kleenet 2008 9 Testing sensor network applications is an essential and a difficult task. Due to their distributed and faulty nature, severe resource constraints, unobservable interactions, and limited human interaction, sensor networks, make monitoring and debugging of applications strenuous and more challenging. In this paper we present KleeNet - a Klee based platform independent bug hunting tool for sensor network applications before deployment - which can automatically test applications for all possible inputs, and hence, ensures memory safety for TinyOS based applications. Upon finding a bug, KleeNet generates a concrete test case with real input values identifying a specific error path in a program. Additionally, we show that KleeNet integrates well into TinyOS application development life cycle with minimum manual effort, making it easy for developers to test their applications. kleenet fileadmin/papers/2008/2008-09-Sasnauskas-FGSN08-BugHunting.pdf ftp://ftp.inf.fu-berlin.de/pub/reports/tr-b-08-12.pdf Print Freie Universität Berlin, Institute of Computer Science

Berlin, Germany

Proceedings of the 7th GI/ITG Fachgespraech Wireless Sensor Networks, Berlin, Germany Chair of Communication and Distributed Systems (ComSys) en 1 RaimondasSasnauskas Jó AgilaBitsch Link Muhammad HamadAlizai KlausWehrle techreport 2008-fgsn-alizai-stle 2008 7 27-30 wld fileadmin/papers/2008/2008-08-alizai-fgsn-stle.pdf ftp://ftp.inf.fu-berlin.de/pub/reports/tr-b-08-12.pdf Print Fachbereich Mathematik und Informatik

Berlin, Germany

Proceedings of the 7th GI/ITG Workshop on Wireless Sensor Networks FGSN 08 September 2010 en 1 Muhammad HamadAlizai OlafLandsiedel KlausWehrle AlexanderBecher techreport 2007-fgsn-alizai-timetossim 2007 7 fileadmin/papers/2008/2007-07-fgsn-alizai-accurate-timing.pdf https://www.ds-group.info/events/fgsn07/fgsn07proc.pdf Print RWTH Aachen

Aachen, Germany

Proceedings of the 6th GI/ITG KuVS Workshop on Wireless Sensor Networks (FGSN 07) RWTH Aachen Aachen, Germany FGSN 07 July 2007 en Muhammad HamadAlizai OlafLandsiedel KlausWehrle