Mobile ad-hoc networks have become increasingly popular in the last years and promise a huge potential for the future. Ad-hoc networks allow users to communicate without a fixed network infrastructure, thus are interesting for many mobile communication scenarios. Multi-hop ad-hoc networks extend the communication range of individual nodes with the help of ad-hoc routing protocols. Many researchers focused on lower communication layers and developed several protocols in the past. In this paper, we want to abstract from the physical layer, the data link layer and routing issues and want to measure the quality of an ad-hoc network independently from network and hardware issues. For this, we first introduce a formal network model and a set of metrics. With the help of a simulation tool, we then measure the quality of ad-hoc networks in specific scenarios. We especially want to discover the prerequisites for sufficient connectivity, stability and coverage. We call the number of nodes to form a reasonable network the critical mass. As a result of our simulations, we get a considerable high critical mass for realistic usage scenarios.

This thesis presents the steps and design decisions followed to develop the architecture of a low-power wireless systems design platform. The design tradeoffs are based on the follow-ing characteristics: easy to program interfaces, flexibility, expandability, low cost and low power. The intended users are researchers or students interested in using a robust and reli-able platform that enables rapid validation of ideas. A method to integrate printed planar antennas directly on the PCB is also presented along with the analysis of its performance and benefits that it provides to the architecture. Applications using the design platform are also detailed. i Résumé Ce mémoire de maîtrise présente les étapes de conception ainsi que les décisions prises dans le développement d’une architecture pour systèmes sans-fils à basse puissance. Les diverses contraintes fûrent: simplicité de programmation des interfaces, flexibilité, capacité d’expansion, faible coût et basse consommation d’énergie. Les utilisateurs ciblés sont des

This paper outlines the potential for the FOAF (Friend Of A Friend) Semantic Web technology to ensure that resources can be defined in a way that promotes their ability for being shared with third-parties with a minimum of integration effort. The paper outlines FOAF's potential for community-building in conferences