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Abstract: Context-aware applications need to react and adapt to changes in their computing environment, which is in general ubiquitous and inherently distributed. Therefore, the context communication faces the problem of context representations heterogeneity, the limitation of devices capacity and network bandwidth. In order to overcome this challenging issue, a particular management of the context is required either for its collection, update, and exchange. In this paper, we propose an approach to manage the context in ubiquitous environments based on the semantic representation of the context and its update using standard languages such as RDF and RDF(s). Our proposed approach provides the simplicity and flexibility that allow the developer to express the context without the need for a unified context model. The results of the experimentation carried out using a prototype implementation of a middleware supports the proposed approach, are in favour of using our approach in the case of resource-constrained devices and network. [ABSTRACT FROM AUTHOR]

This paper describes an algorithm for reformulation of XQuery queries. The mediation is based on an essential component called mediator. Its main role is to reformulate a user query, written in terms of global schema, into queries written in terms of source schemas. Our algorithm is based on the principle of logical equivalence, simple and complex unification, to obtain a better reformulation. It takes XQuery query, global schema (written in XMLSchema), and mappings GLAV as input parameters and provides resultant query written in terms of source schemas. The results of implementation show the proper functioning of the algorithm. [ABSTRACT FROM AUTHOR]

Abstract: We propose an intelligent and an efficient query processing approach for semantic mediation of information systems. We propose also a generic multi agent architecture that supports our approach. Our approach focuses on the exploitation of intelligent agents for query reformulation and the use of a new technology for the semantic representation. The algorithm is self-adapted to the changes of the environment, offers a wide aptitude and solves the various data conflicts in a dynamic way; it also reformulates the query using the schema mediation method for the discovered systems and the context mediation for the other systems. [Copyright &y& Elsevier]