This dissertation presents my interest in developing methods and algorithms necessary for realizing advanced applications for the Semantic Web. This extension of the current Web aims to allow the integration and sharing of data across organizations and applications. A direct consequence of the success of this approach would enable to consider the Web as a global database containing the data stored on all connected machines. This aspect is well translated on the W3C Semantic Web Activity web site which states that the Semantic Web is a Web of Data. Thereby, this Web of Data will permit to submit structured queries on all accessible connected datasets and to retrieve relevant results coming from diverse and heterogeneous sources. A main issue related to this heterogeneity aspect concerns the notion of semantics. In the context of the Semantic Web, this is generally tackled with ontologies and associated mediation operations. My research is anchored into these topics and this dissertation aims at presenting some of my investigations, results as well as to describe some of the applications I have designed and implemented.
