USING ONTOLOGIES TO IMPROVE PERFORMANCE IN A WEB SYSTEM - A Web Caching System Case of Study Topics: Distributed and Parallel Applications; Network Systems, Proxies and Servers; Ontology and the Semantic Web; Web Services and Web Engineering; XML and Data Management In Proceedings of the Fourth International Conference on Web Information Systems and Technologies - Volume 2: WEBIST, 117-122, 2008 , Funchal, Madeira, Portugal