Basser Seminar Series

From Inexpressive to Expressive Languages and Back

Franz Baader
TU Dresden, Germany

Monday 18 December 2006, 11am NB different time and day

School of IT Building, Lecture Theatre 123, Level 1


Description Logics (DL) are a successful family of logic-based knowledge representation languages, which can be used to represent the conceptual knowledge of an application domain in a structured and formally well-understood way. They are employed in various application domains, such as natural language processing, configuration, and databases, but their most notable success so far is the adoption of the DL-based language OWL as standard ontology language for the semantic web. OWL is based on a very expressive language with worst-case intractable reasoning problems.

The talk will first give a brief introduction into DL and an overview of the research in this area of the last 20 years. It will then argue that the fact that there are effective and practically useful reasoning procedures for the DL underlying OWL strongly depends on this fundamental research, without which the development of OWL would not have been possible. In spite of these successes of expressive languages, OWL and existing reasoners for OWL are not appropriate for all ontology applications. The talk will describe the more recent development of polynomial-time reasoning procedures for less expressive description logics, which can deal with very large biomedical ontologies much better than the existing highly- optimised OWL reasoners.

Speaker's biography

Franz Baader received his Ph.D. in Computer Science from the University of Erlangen in 1989. From 1989-1993 he was a senior researcher at the German Research Center for AI (DFKI) in Kaiserslautern and Saarbrücken. In 1993 he was appointed as associate professor for computer science at RWTH Aachen, and in 2002 as full professor for computer science at TU Dresden.

His research interests include knowledge representation (in particular, description logics, nonmonotonic logics, and modal logics) and automated deduction (in particular, unification theory, term rewriting systems, and combination of constraint solving methods).