Design and implementation of information retrieval system based ontology

Nowadays, the resources available on the web increases significantly. It then has a large volume of information, but without mastery of content. In this immense data warehouse research of current information retrieval systems do not allow users to obtain results to their requests that meet exactly their needs. This is due in large part to indexing techniques (key words, thesaurus). The result is that the user of the web wasting much of his time to examine a large number of Web page by searching for what he needs, because the Web does not provide service in this direction. The Semantic Web is the solution; this new vision of the web is to make web resources not only understandable by humans but also by machines. To improve the relevance of information retrieval, we propose in this paper an approach based on the use of domain ontology for indexing a collection of documents and the use of semantic links between documents in the collection to allow the inference of all relevant documents. The work involves the implementation of a system based on the use of OWL ontology for research pedagogical documents. In this case, the descriptors are not directly chosen in the documents but in the ontology and are indexed by concepts that reflect their meaning rather than words are often ambiguous. To perform a search based on meaning, documents and their descriptors are stored in OWL ontologies describing the documentary features of a document. The objective is to design two types of OWL ontologies: document ontology reserved for storage of all pedagogical documents and domain ontology reserved for well-structured of documents stored in the level of the document ontology and each document is indexed by its keywords and their synonyms.