My PapersThese pages contains my written work. Published PapersAn Evaluation of an OSGi-Based Residential Pervasive Computing PlatformKlaus Marius Hansen, Simon Bo Larsen, Jakob Illeborg Pagter, Michael Østergaard Pedersen, and Jonas Thomsen. An Evaluation of an OSGi-Based Residential Pervasive Computing Platform. In Proceedings of the IADIS Applied Computing Conference, pages 246-253, 2004. Abstract: Residential applications including home control, alarm systems, and monitoring services is an area in which pervasive computing systems are currently emerging. One problem facing technology and service providers is getting a view on and analysis of technological and commercial problems and opportunities. As a step towards that, we present an analysis and evaluation of a widely-used setup for residential pervasive computing applications, viz., a setup based on a residential gateway with an Open Services Gateway Initiative (OSGi) implementation. The analysis is anchored in use, through scenarios and prototyping, and employs architectural, security, and business perspectives. Furthermore, we present challenges to be met to enhance technological and commercial opportunities for this platform.
Evaluating the Use of Motes and TinyOS for a Mobile Sensor PlatformJonas Thomsen and Dirk Husemann. Evaluating the Use of Motes and TinyOS for a Mobile Sensor Platform. In Proceedings of the IASTED International Conference on Parallel and Distributed Computing and Networks (PDCN), pages 95-100, 2006. Abstract: Monitoring containers during transport in a secure, tamper resistant, and reliable manner, is the subject of the IBM Secure Trade Lane (STL) project. We have evaluated a platform based on motes (i.e. very small computers) and TinyOS as the base for communication in STL. We implemented an IEEE 802.15.4 full functional device (FFD) MAC layer with beacon support, and we discovered that running this MAC layer was too much for the motes. We saw starvation and we experienced a far too slow data transfer between layers in TinyOS. We tried to overcome the starvation problems by introducing means to limit the high number of timer interrupts required by the MAC layer. Our approach is called Adaptive Timer Resolution, but it did not solve our problems in this case. We concluded that motes and TinyOS are insufficient for the 802.15.4 FFD MAC layer and that this platform is having problems running applications with a high frequency of interrupts, and still execute useful code in between. Our contributions are the evaluation of the mote platform by pushing it beyond its limits and our timer resolution control mechanism Adaptive Timer Resolution.
OSGi-based Gateway ReplicationJonas Thomsen. OSGi-based Gateway Replication. In Proceedings of the IADIS Applied Computing Conference 2006, pages 123-129, 2006. Abstract: Modern home automation systems are using OSGi-based residential gateways as the base component of the system. Having one central component being responsible for controlling the entire residence also adds a single point of failure for the residence. In this paper we propose means of eliminating this single point of failure by adding distributed redundancy to the system and being able to replicate the entire system to sub-gateways which will be responsible for operating the residence in islands, in case of a failure in the main residential gateway.
Technical ReportsComming soon... PhD ThesisHome Appliance Integration by Pervasive ComputingJonas Thomsen. Home Appliance Integration by Pervasive Computing. PhD Dissertation, Department of Computer Science, University of Aarhus, 2006. Abstract: Electronic appliances are emerging in all directions, but the users, however, become increasingly frustrated by not being able to understand the appliances they buy, and thereby not exploiting the full potential of them. The gap between users and technology will continue to increase, if nothing is done. One way to narrow the gap is by integrating the residential appliances in such a way that the users have a unified way of accessing, controlling, and monitoring their appliances. My work focuses on specific areas of integrating residential appliances. I have addressed the residential gateway architecture from several angles, including prototyping of integration and increasing availability of residences based on the residential gateway in case of a failure in the residential gateway. I have addressed wireless sensor network platforms to evaluate their abilities to perform more advanced tasks than just sensing, and I have concluded that our specific goals for those platforms could not be fulfilled. The dissertation consists of three parts: Part I gives an overview of the area of integrating residential appliances. In this overview I describe the current and emerging state of residential communication, integration and interaction, and I place my own contributions into their natural contexts. Furthermore, I introduce novel ideas and solutions to integrate residential appliances, e.g., introducing a Secure Middle Device to connect new appliances to a cryptographically secured residential communication system, and using dynamic DVD menus to show user interfaces on practically all modern displays. Part II consists of three individual papers on different aspects of integrating residential appliances, all have been published as conference papers. Part III consists of two currently unpublished technical reports covering energy management and saving by means of integrating residential appliances. Master's ThesisAnalysis of GSM Handover using Coloured Petri NetsMy master's thesis was about "Analysis of GSM Handover using Coloured Petri Nets". It was written in coorporation with René Manggaard. You can download the thesis here:
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