Bitte wählen Sie ihr Lieferland und ihre Kundengruppe
Several nonmonotonic extensions are investigated to description logics (DLs), namely autoepistemic DLs, circumscriptive DLs and terminological default rules, all of which extend standard DL inference mechanisms by forms of closed-world and default reasoning associated to common-sense features. We establish a matchmaking framework for semantic resource descriptions formulated in the DL formalism that uses various DL inferences to judge about resource compatibility. Special emphasis is put on mapping the technical formalities of model-theoretic semantics of DLs to more intuitive notions that abstract from the details of logic for the framework's easier adoption in applications. Moreover, we incorporate the common-sense features realised by nonmonotonic DLs into the matchmaking mechanism to improve matching behaviour in situations where semantic resource descriptions are incomplete. Based on this framework, it is applied the technique of matchmaking to the problem of service discovery in the Semantic Web with services annotated by OWL descriptions formulated in terms of domain ontologies. It is evaluated the thus obtained service discovery mechanism by testing its applicability and usefulness in a concrete application scenario taken from a project case study in the logistics domain. The particular contributions of this thesis span the fields of nonmonotonic reasoning with description logics in Artificial Intelligence, matchmaking of ontology-based descriptions and Semantic Web Service discovery. A novel tableaux calculus is introduced for reasoning in circumscriptive DLs, and it is demonstrated how the various nonmonotonic extensions to description logics can be used to realise common-sense features and local closed-world reasoning in a Semantic Web setting in general. It is characterised the use of various DL inferences for solving the matchmaking problem and show how different realisations of local closed-world reasoning help to overcome problems that arise due to the open-world semantics of OWL and classical DLs. It is also provided initial methodological guidance to the modelling of semantic resource descriptions in the context of matchmaking. Furthermore, we position our semantic matchmaking technique as an adequate tool for supporting Semantic Web Service discovery and demonstrate its applicability in a concrete use case scenario.