TY - CONF T1 - EL-ifying Ontologies T2 - Automated Reasoning - 7th International Joint Conference, IJCAR 2014, Held as Part of the Vienna Summer of Logic, {VSL} 2014, Vienna, Austria, July 19-22, 2014. Proceedings Y1 - 2014 A1 - David Carral A1 - Cristina Feier A1 - Cuenca Grau, Bernardo A1 - Pascal Hitzler A1 - Ian Horrocks KW - description logics KW - OWL KW - Rewriting KW - Tractable Reasoning AB -

The OWL 2 profiles are fragments of the ontology language OWL 2 for which standard reasoning tasks are feasible in polynomial time. Many OWL ontologies, however, contain a typically small number of out-of-profile axioms, which may have little or no influence on reasoning outcomes. We investigate techniques for rewriting axioms into the EL and RL profiles of OWL 2. We have tested our techniques on both classification and data reasoning tasks with encouraging results.

JF - Automated Reasoning - 7th International Joint Conference, IJCAR 2014, Held as Part of the Vienna Summer of Logic, {VSL} 2014, Vienna, Austria, July 19-22, 2014. Proceedings UR - http://dx.doi.org/10.1007/978-3-319-08587-6_36 ER - TY - CONF T1 - Pushing the Boundaries of Tractable Ontology Reasoning T2 - The Semantic Web - ISWC 2014 - 13th International Semantic Web Conference, Riva del Garda, Italy, October 19-23, 2014. Proceedings, Part II Y1 - 2014 A1 - David Carral A1 - Cristina Feier A1 - Cuenca Grau, Bernardo A1 - Pascal Hitzler A1 - Ian Horrocks KW - description logics KW - OWL KW - Tractable Reasoning AB -

We identify a class of Horn ontologies for which standard reasoning tasks such as instance checking and classification are tractable. The class is general enough to include the OWL 2 EL, QL, and RL profiles. Verifying whether a Horn ontology belongs to the class can be done in polynomial time. We show empirically that the class includes many real-world ontologies that are not included in any OWL 2 profile, and thus that polynomial time reasoning is possible for these ontologies.

JF - The Semantic Web - ISWC 2014 - 13th International Semantic Web Conference, Riva del Garda, Italy, October 19-23, 2014. Proceedings, Part II UR - http://dx.doi.org/10.1007/978-3-319-11915-1_10 ER - TY - CONF T1 - Is Your Ontology as Hard as You Think? Rewriting Ontologies into Simpler DLs T2 - Informal Proceedings of the 27th International Workshop on Description Logics, Vienna, Austria, July 17-20, 2014. Y1 - 2014 A1 - David Carral A1 - Cristina Feier A1 - Ana Armas Romero A1 - Cuenca Grau, Bernardo A1 - Pascal Hitzler A1 - Ian Horrocks KW - description logics KW - OWL KW - Tractable Reasoning AB -

We investigate cases where an ontology expressed in a seemingly hard DL can be polynomially reduced to one in a simpler logic, while preserving reasoning outcomes for classification and fact entailment. Our transformations target the elimination of inverse roles, universal and existential restrictions, and in the best case allow us to rewrite the given ontology into one of the OWL 2 profiles. Even if an ontology cannot be fully rewritten into a profile, in many cases our transformations allow us to exploit further optimisation techniques. Moreover, the elimination of some out-of-profile axioms can improve the performance of modular reasoners, such as MORe. We have tested our techniques on both classification and data reasoning tasks with encouraging results.

JF - Informal Proceedings of the 27th International Workshop on Description Logics, Vienna, Austria, July 17-20, 2014. UR - http://ceur-ws.org/Vol-1193/paper_75.pdf ER -