Abstract. Recent research showed the benefits of adopting formal ontologies as a means for accessing heterogeneous data sources. The use of an ontology not only provides a uniform...
Rewriting queries using views is a powerful technique that has applications in data integration, data warehousing and query optimization. Query rewriting in relational databases i...
A graphical formalized language is proposed for specifying systems of views over database schemas. The language is based on the notion of arrow (mapping) between data schemas and ...
In this paper we propose a mediator architecture for the querying and integration of Web-accessible XML data sources. Our contributions are (i) the definition of a simple but expr...
The RDF data model is gaining importance for applications in computational biology, knowledge sharing, and social communities. Recent work on RDF engines has focused on scalable p...