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Location-aware systems have attracted much attention from academic and industrial users. Location detection or positioning devices are required in order to get location information. Bluetooth is often used to detect the users' location in indoor location-aware applications. This paper integrates the Blip devices, which are based on Bluetooth technologies, into location-aware applications. A service oriented method is proposed to provide more flexibility and extensibility of the system. The prototype of CPH AirNotes with Blip devices is developed to show that the proposed method's effectiveness. Also the performance analysis of Blip is discussed according to experiences with CPH AirNotes.

Abstract-One of the most important points in context-aware computing is to build a reasonable context model. Currently, many models were not built in a common structure. It is hard to build other models depending on the existing ones. In this paper, we build a common ontology-based context model with Web Ontology Language (OWL), which provides an efficient and convenient way of ontology-building by adding domainspecific concepts into this common model. We show the structure of the model and explain the main concepts of it. With the common model, we propose our solutions to solve the problems of position and context history that may exist in the process of modeling a specific domain. Finally, we show a context model of Beijing Capital International Airport (BCIA), which was built on the common model. A simple reasoning test is run on the BCIA model with Semantic Web Rule Language (SWRL).

Abstract

Context-aware applications demand for a distributed middleware that can collect, aggregate and deliver contextual data for applications. This paper presents one of the main components, Context-Sources Abstraction (CSA), in a middleware for building context-aware applications. The CSA component includes a set of query interfaces and an event notification mechanism to applications. In this way, the access to the hardware are encapsulated by the middleware and virtualized to the end-point applications. The architecture of the CSA and the common functions of CSA are discussed.