N. Bassiliades, G. Antoniou, I. Vlahavas, “A Defeasible Logic Reasoner for the Semantic Web”, Third International Workshop on Rules and Rule Markup Languages for the Semantic Web (RuleML 2004), G. Antoniou, H. Boley (Ed.), Springer-Verlag, LNCS 3323, pp. 49-64, Hiroshima, Japan, 8 Nov. 2004, 2004.
Defeasible reasoning is a rule-based approach for efficient reasoning with incomplete and inconsistent information. Such reasoning is, among others, useful for ontology integration, where conflicting information arises naturally; and for the modeling of business rules and policies, where rules with exceptions are often used. This paper describes these scenarios in more detail, and reports on the implementation of a system for defeasible reasoning on the Web. The system is called DR-DEVICE and is capable of reasoning about RDF metadata over multiple Web sources using defeasible logic rules. The system is imple-mented on top of CLIPS production rule system and builds upon R-DEVICE, an earlier deductive rule system over RDF metadata that also supports derived attribute and aggregate attribute rules. Rules can be expressed either in a native CLIPS-like language, or in an extension of the OO-RuleML syntax. The opera-tional semantics of defeasible logic are implemented through compilation into the generic rule language of R-DEVICE. The paper includes a complete exam-ple of a semantic web broker that reasons about apartment renting.
