The Semantic Web Rule Language (SWRL) is a W3C member submission rule language for ontologies. It is based on a combination of the OWL DL and OWL Lite sublanguages of the OWL Web Ontology Language with the Unary/Binary Datalog RuleML sublanguages of the Rule Markup Language. In this paper we propose a transformation of SWRL rules into the object-oriented rule language of CLIPS (COOL). The purpo...

The Semantic Web (SW) has been envisioned to enable software tools or Web Services, respectively, to process information provided on the Web automatically. For this purpose, languages for representing the semantics of data by means of ontologies have been proposed such as RDF(S) and OWL. While the semantics of RDF(S) requires a non-standard model-theory that goes beyond first order logics, OWL ...

One of the most salient tasks in law is legal assessment, and concerns the problem of determining whether some case is allowed or disallowed given an appropriate body of legal norms. In this paper we describe a system and Protégé 4 plugin, called OWL Judge, that uses standard OWL 2 DL reasoning for legal assessment. Norms are represented in terms of the LKIF Core ontology, as generic situation ...

Knowledge representation and reasoning on the Semantic Web is done by means of ontologies. While the quest for suitable ontology languages is still ongoing, OWL [5] has been established as a core standard. It comes in three flavours, as OWL Full, OWL DL and OWL Lite, where OWL Full contains OWL DL, which in turn contains OWL Lite. The latter two coincide semantically with certain description lo...

Abstract Ontology-mediated querying (OMQ) provides a paradigm for query answering according to which users not only records at the database but also implicit information inferred from ontology. A key challenge in OMQ is that may be infinite, cannot stored and queried by off -the -shelf engine. The commonly adopted technique deal with infinite entailments rewriting, which, however, comes cost of...

Being able to extend an OWL ontology with some form of rules is a feature that many ontology developers consider as very important. Nevertheless, working with rules in practice can be difficult since the tool support is not as good as for handling ontologies without rules. Furthermore, the existing rule syntaxes are not very well aligned with the new OWL 2 standard. We propose, therefore, an ex...

A key issue in semantic reasoning is the computational complexity of inference tasks on expressive ontology languages such as OWL DL and OWL 2 DL. Theoretical works have established worst-case complexity results for reasoning tasks for these languages. However, hardness of reasoning about individual ontologies has not been adequately characterised. In this paper, we conduct a systematic study t...