Volker Haarslev

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RACER implements a TBox and ABox reasoner for the logic SHIQ. RACER was the first full-fledged ABox description logic system for a very expressive logic and is based on optimized sound and complete algorithms. RACER also implements a decision procedure for modal logic satisfiability problems (possibly with global axioms).
This paper presents a method for reasoning about spatial objects and their qualitative spatial relationships. In contrast to existing work, which mainly focusses on reasoning about qualitative spatial relations alone, we integrate quantitative and qualitative information with terminological reasoning. For spatioterminological reasoning we present the(More)
Agent systems that search the Semantic Web are seen as killer applications for description logic (DL) inference engines. The guiding examples for the Semantic Web involve information and document retrieval tasks. The instance retrieval inference service of description logic inference engines can be used as a basic machinery for implementing agent-based(More)
We present an empirical analysis of optimization techniques devised to speed up the so-called TBox classification supported by description logic systems which have to deal with very large knowledge bases (e.g. containing more than 100,000 concept introduction axioms). These techniques are integrated into the RACE architecture which implements a TBox and(More)
RACE [3] is a successor of HAM-ALC [5, 2]. Based on sound and complete algorithms RACE currently implements TBox and ABox reasoning for the description logic ALCNHR+ [4] that supports number restrictions, role hierarchies, and transitively closed roles. Note that this DL implies general concept inclusions as a language feature. RACE accepts TBoxes and(More)