Francesco M. Donini

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We present an integrated system for knowledge representation, calledAL -log, based on description logics and the deductive database language Datalog. AL-log embodies two subsystems, called structural and relational. The former allows for the definition of structural knowledge about classes of interest (concepts) and membership relation between objects and(More)
Termino log ica l Knowledge Representation Systems (TKRSs ) are tools for designing and using knowledge bases tha t make use of te rminological languages (or concept languages). The T K R S we consider in this paper is of pract i cal interest since it goes beyond the capabi l it ies of presently avai lable T K R S s . F i rs t , our T K R S is equipped w i(More)
tively used in the construction of knowledge-based applications in several domains (see for example Wright et al. 1993), like connguration and software engineering. Recently we have seen attempts to use them in the elds of machine learning (see for example Cohen and Hirsh 1994) and planning (see for example Devambu and Litman 1991, Weida and Litman 1992,(More)
ur K ¨ unstliche In-telligenz, DFKI) with sites in Kaiserslautern and Saarbrücken is a non-profit organization which was founded in 1988. The DFKI conducts application-oriented basic research in the field of artificial intelligence and other related subfields of computer science. The overall goal is to construct systems with technical knowledge and common(More)
Description iogics (aiso caiied terminoiogicai iogics, or concept ianguagesj are fragments of first-order logic that provide a formal account of the basic features of frame-based systems. However, there are aspects of frame-based systems-such as nonmonotonic reasoning and procedural rules-that cannot be characterized in a standard first-order framework.(More)
We propose a tableaux calculus requiring simple expo nential time for satis ability of an ALC concept C wrt a TBox T containing general axioms of the form C v D From correspondences with Propositional Dynamic Logic PDL it is known that this problem is in EX PTIME Pratt Vardi and Wolper How ever an algorithm directly derived from the methods used to prove(More)
It is a common opinion that subsumption is the central reasoning task in frame-based knowledge representation languages (or concept languages). Intuitively, a concept C subsumes another concept D if the set of objects represented by C is a superset of the one represented by D. When individual objects are taken into account, the basic deduc-tive task for(More)
Motivated by the matchmaking problem in electronic marketplaces, we study abduction in Description Logics. We devise suitable definitions of the problem, and show how they can model commonsense reasoning usually employed in analyzing classified announcements having a standardized terminology. We then describe a system partially implementing these ideas, and(More)
Knowledge compilation is an AI technique for addressing computationally demanding reasoning problems. In this paper we survey recent results in knowledge compilation of propositional knowledge bases. We first define and limit the scope of such a technique, then we survey exact and approximate knowledge compilation methods. We include a discussion of(More)
More and more resources are becoming available on the Web, and there is a growing need for infrastructures that, based on advertised descriptions, are able to semantically match demands with supplies.We formalize general properties a matchmaker should have, then we present a matchmaking facilitator, compliant with desired properties.The system embeds a(More)