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Everyone agrees that user interactions and social networks are among the cornerstones of " Web 2.0 ". Web 2.0 applications generally run in a web browser, propose dynamic content with rich user interfaces, offer means to easily add or edit content of the web site they belong to and present social network aspects. Well-known applications that have helped(More)
This paper presents an ontology-based approach for web querying, using semantic metadata. We propose a query language based on ontologies and emphasize its ability to express approximate queries, useful for an efficient information retrieval on the web. We present the Corese search engine dedicated to RDF(S) metadata and illustrate it through several(More)
Querying and linking distributed and heterogeneous databases is increasingly needed, as plentiful data resources are published over the Web. This work describes the design of a versatile query system named KGRAM that supports (i) multiple query languages among which the SPARQL 1.1 standard, (ii) federation of multiple heterogeneous and distributed data(More)
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt età la diffusion(More)
The semantic Web aims to represent the contents of Web resources in formalisms that both programs and humans can understand. It relies on rich metadata, called semantic annotations, offering explicit semantic descriptions of Web resources. These annotations are built on ontologies, representing domains through their concepts and the semantic relations(More)
6i†‡…hp‡ In this paper, we present a method for learning ontologies from RDF annotations of Web resources by systematically generating the most specific generalization of all the possible sets of resources. The preliminary step of our method consists in extracting (partial) resource descriptions from the whole RDF graph gathering all the annotations. In(More)
In this paper we present the KGRAM abstract machine dedicated to querying knowledge graphs. It is the result of an abstraction process we performed to reach a generic solution to the problem of querying graphs in various models. We identified high level abstract primitives that constitute the expressions of the query language and the interfaces of KGRAM for(More)