Maria-Esther Vidal

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Following the design rules of Linked Data, the number of available SPARQL endpoints that support remote query processing is quickly growing; however, because of the lack of adaptivity, query executions may frequently be unsuccessful. First, fixed plans identified following the traditional optimize-thenexecute paradigm, may timeout as a consequence of(More)
There is an increase in the number of data sources that can be queried across the WWW. Such sources typically support HTML forms-based interfaces and search engines query collections of suitably indexed data. The data is displayed via a browser. One drawback to these sources is that there is no standard programming interface suitable for applications to(More)
Life science data sources represent a complex link-driven federation of publicly available Web accessible sources. A fundamental need for scientists today is the ability to completely explore all relationships between scientific classes, e.g., genes and citations, that may be retrieved from various data sources. A challenge to such exploration is that each(More)
A large number of SPARQL endpoints are available to access the Linked Open Data cloud, but query capabilities still remain very limited. Thus, to support efficient semantic data management of federations of endpoints, existing SPARQL query engines require to be equipped with new functionalities. First, queries need to be decomposed into sub-queries not only(More)
We consider the problem of rewriting a query efficiently using materialized views. In the context of information integration, this problem has received significant attention in the scope of emerging infrastructures such as WWW, Semantic Web, Grid, and P2P which require efficient algorithms. The problem is in general intractable, and the current algorithms(More)
We present a deductive approach that supports resource discovery. The BiOnMap Web service is designed to support the selection of resources suitable to implement specific tasks. The BiOnMap service is comprised of a metadata catalog and a reasoning engine. The metadata catalog uses domain ontologies to annotate resources semantically and express domain(More)
The World Wide Web has become the preferred medium for the dissemination of information in virtually every domain of activity. Standards and formats for data interchange have addressed the issue of interoperability among heterogeneous sources. However, access to data is still hindered by the challenge of locating data relevant to a particular problem.(More)