Prof. Dr. Ralf Möller
Software, Technology and Systems Group (STS),
Hamburg University of Technology (TUHH)
Publications
2004
S. Bechhofer, V. Haarslev, C. Lutz, and R. Möller, editors.
KI-2004 Workshop on Applications of Description Logics (ADL'04), 2004.
Available
at CEUR Workshop Proceedings</A>.
Bibtex entry
V. Haarslev and R. Möller, editors.
International Workshop on Description Logics (DL2004), 2004.
Available
as CEUR Workshop Proceedings</A>.
Bibtex entry Paper (PDF)
V. Haarslev and R. Möller.
Optimization Techniques for Retrieving Resources Described in OWL/RDF
Documents: First Results.
In Ninth International Conference on the Principles of Knowledge
Representation and Reasoning, KR 2004, Whistler, BC, Canada, June 2-5,
pages 163–173, 2004.
Bibtex entry Paper (PDF)
Abstract
Practical description logic systems play an ever-growing role for knowledge representation and reasoning research even in distributed environments. In particular, the often-discussed semantic web initiative is based on description logics (DLs) and defines important challenges for current system implementations. Recently, several standards for representation languages have been proposed (RDF, OWL). By introducing optimization techniques for inference algorithms we demonstrate that sound and complete query engines for semantic web representation languages can be built for practically significant query classes. The paper introduces and evaluates optimization techniques for the instance retrieval problem w.r.t. the description logic SHIQ(Dn)-, which covers large parts of OWL. The paper discusses practical experiments with the description logic system Racer.
V. Haarslev, R. Möller, R. van der Straeten, and M. Wessel.
Extended Query Facilities for Racer and an Application to
Software-Engineering Problems.
In Proceedings of the 2004 International Workshop on Description Logics
(DL-2004), Whistler, BC, Canada, June 6-8, pages 148–157, 2004.
Bibtex entry Paper (PDF)
Abstract
This paper introduces a description logic query language for retrieving A-box individuals that satisfy specific conditions. The language is substantially more expressive than traditional concept-based retrieval languages offered by previous description logic reasoning systems. The new language is implemented in the Racer system. We demonstrate the applicability of nRQL (new Racer Query Language) to OWL semantic web repositories and evaluate the performance of the current state of the art query answering engines for description logics using the Lehigh University Benchmark (LUBM).
V. Haarslev, R. Möller, and M. Wessel.
Querying the Semantic Web with Racer + nRQL.
In Proceedings of the KI-2004 International Workshop on Applications of
Description Logics (ADL'04), Ulm, Germany, September 24, 2004.
Bibtex entry Paper (PDF)
Abstract
This paper introduces a description logic query language for retrieving A-box individuals that satisfy specific conditions. The language is substantially more expressive than traditional concept-based retrieval languages offered by previous description logic reasoning systems. The new language is implemented in the Racer system. We demonstrate the applicability of nRQL (new Racer Query Language) to OWL semantic web repositories and evaluate the performance of the current state of the art query answering engines for description logics using the Lehigh University Benchmark (LUBM).
R. Möller, V. Haarslev, and B. Neumann.
Expressive Description Logics for Agent-Based Information Retrieval.
In Y J. Cuena, Demazeau, A. Garcia, and J. Treur, editors, Knowledge
Engineering and Agent Technology, Volume 52, Frontiers in Artificial
Intelligence and Applications. IOS Press, 2004.
Bibtex entry Paper (PDF)
Abstract
In this contribution we investigate the use of description logics (DLs) for information retrieval in a multiagent scenario. We first describe two advanced DLs and present the relevant reasoning services provided for information retrieval, in particular instance retrieval, instance checking and example-based instance retrieval. Complete and sound algorithms exist for each of these tasks in both DLs, but it is shown that a combined DL is undecidable. In order to make use of knowledge bases which use different DLs, a broker-based multiagent information retrieval scheme is presented. The main idea is to pose transformed queries to individual agents and combine the answers to obtain a correct but not necessarily complete result. The approach is illustrated with detailed examples.
B. Neumann and R. Möller.
On Scene Interpretation with Description Logics.
Technical Report FBI-B-257/04, University of Hamburg, Computer Science
Department, 2004.
Bibtex entry Paper (PDF)
Abstract
We examine the possible use of Description Logics as a knowledge representation and reasoning system for high-level scene interpretation. It is shown that aggregates composed of multiple parts and constrained primarily by temporal and spatial relations can be used to represent high-level concepts such as object configurations, occurrences, events and episodes. Scene interpretation is modelled as a stepwise process which exploits the taxonomical and compositional relations between aggregate concepts while incorporating visual evidence and contextual information. It is shown that aggregates can be represented by a Description Logic ALCF(D) which provides feature chains and a concrete domain extension for quantitative temporal and spatial constraints. Reasoning services of the DL system can be used as building blocks for the interpretation process, but additional information is required to generate preferred interpretations. A probabilistic model is sketched which can be integrated with the knowledge-based framework.