SoftFacts: a top-k retrieval engine for a tractable description logic accessing relational databases

We outline Softfacts, an ontology mediated top-k information retrieval system over relational databases. An ontology layer is used to define (in terms of a tractable DLR-Lite like description logic) the relevant abstract concepts and relations of the application domain, while facts are stored into a relational database. The results of a query may be ranked according to some scoring function. We will illustrate its logical model, its architecture, its representation and query language, the reasoning algorithms and the experiments we conducted.