Apprendre les points communs dans RDF et SPARQL
Sara El Hassad · theses.fr (ABES) · 2018
Finding commonalities between descriptions of data or knowledge is a fundamental task in Machine Learning. The formal notion characterizing precisely such commonalities is known as least general generalization of descriptions and was introduced by G. Plotkin in the early 70's, in First Order Logic. Identifying least general generalizations has a large scope of database applications ranging from query optimization (e.g., to share commonalities between queries in view selection or multi-query optimization), to recommendation in social networks (e.g., to establish connections between users based on their commonalities between proles or searches), through exploration (e.g., to classify/categorize datasets and to identify common social graph patterns between organizations (e.g., criminal ones)). In this thesis we revisit the notion of least general generalizations in the entire Resource Description Framework (RDF) and popular conjunctive fragment of SPARQL, a.k.a. Basic Graph Pattern (BGP) queries. By contrast to the literature, we do not restrict the structure nor semantics of RDF graphs and BGPQs. Our contributions include the denition and the computation of least general generalizations in these two settings, which amounts to nding the largest set of commonalities between incomplete databases and conjunctive queries, under deductive constraints. We also provide an experimental assessment of our technical contributions.