citizen of Germany accepted on the recommendation of

Abstract

ii Ubiquitous computing has the goal of enhancing computer use by making many computers available throughout the physical environment, and thus providing the technical and conceptual means for enabling anytime, anywhere, anyhow computing. The technical realization of this vision has become feasible owing to recent advances in miniaturization and embedded computing technologies, which enable the integration of diverse computing capabilities into manifold everyday objects and devices. The multitude and diversity of computerized entities that are part of ubiquitous computing systems imply a number of technical challenges. On one side, the differences in form factors, functionality, and technical capabilities result in a great level of diversity of hardware and software, and a distinct heterogeneity in capabilities. Further, ubiquitous computing systems in general are often highly decentralized, featuring an exceptionally high volatility of cooperative relationships and topologie