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Development of context-aware applications is inherently complex. These applications adapt to changing context information: physical context, computational context , and user context/tasks. Context information is gathered from a variety of sources that differ in the quality of information they produce and that are often failure prone. The pervasive computing(More)
In this paper, we address the data management aspect of large-scale pervasive computing systems. We aim at building an infrastructure that simultaneously supports many kinds of context-aware applications, ranging from room level up to nation level. This all-embracing approach gives rise to synergetic benefits like data reuse and sensor sharing. We identify(More)
Meta data - data about data - improves the value of the operational data by giving applications and users additional information on the data's origin, its precision or staleness. We outline the benefits of modeling meta data in context models: it can be used for resource finding, enhanced data selection, trust and data quality issues and sensor fusion. We(More)
Semantic Web technologies, most notably RDF, are well-suited to cope with typical challenges in spatial data management including analyzing complex relations between entities, integrating heterogeneous data sources and exploiting poorly structured data, e.g., from web communities. Also, RDF can easily represent spatial relationships, as long as the location(More)
We present the design and implementation of a component for the preprocessing of position data taken from moving objects. The movement of mobile objects is represented by piece wise functions over time that approximate the real object movement and significantly reduce the initial data volume such that efficient storage and analysis of object trajectories(More)
In 1995, Mark Weiser introduced a scenario about the future life, where everyday objects are equipped with smart functions and the environment helps us to fulfill our everyday tasks. This paper shows how Weiser's scenario can be realized by today's available technologies. We combine PerFlows (to model the flow of daily tasks) and the Nexus context(More)
Sensors and their observations are used in almost all pervasive applications to configure and adjust the behavior of applications to the user's need. However, the quality of those sensor observations are influenced by different factors including the physical or chemical principle of measurement, the internal processing of the sensing device, and the(More)