Prof. Dr. Ralf Möller
Software, Technology and Systems Group (STS),
Hamburg University of Technology (TUHH)


Publications


2008


S. Castano, S. Espinosa, A. Ferrara, V. Karkaletsis, A. Kaya, R. Möller, S. Montanelli, G. Petasis, and M. Wessel. Multimedia Interpretation for Dynamic Ontology Evolution. In Journal of Logic and Computation, volume 19, pages 859–897. Oxford University Press, 2008.
Bibtex entry  Paper (PDF)

Abstract

The recent success of distributed and dynamic infrastructures for knowledge sharing has raised the need for semiautomatic/automatic ontology evolution strategies. Ontology evolution is generally de ned as the timely adaptation of an ontology to changing requirements and the consistent propagation of changes to dependent artifacts. In this article, we present an ontology evolution approach in the context of multimedia interpretation. Ontology evolution in this context relies on the results obtained through reasoning for the interpretation of multimedia resources, through population of the ontology with new individuals, or through enrichment of the ontology with new concepts and new semantic relations. The article analyses the results of interpretation, population and enrichment obtained in evaluation experiments in terms of measures such as precision and recall. The evaluation reveals encouraging results.


S. Castano, A. Ferrara, D. Lorusso, T. H. Nšth, and R. Möller. Mapping Validation by Probabilistic Reasoning. In Proc. 5th European Semantic Web Conference (ESWC 2008).
Bibtex entry  Paper (PDF)

Abstract

In the semantic web environment, where several independent ontologies are used in order to describe knowledge and data, ontologies have to be aligned by defining mappings among the elements of one ontology and the elements of another ontology. Very often, mappings are not derived from the semantics of the ontologies that are compared. Rather, mappings are computed by evaluating the similarity of the ontologies terminology and/or of their syntactic structure. In this paper, we propose a new mapping validation approach. The approach is based on the notion of probabilistic mappings and on the use of probabilistic reasoning techniques to enforce a semantic interpretation of similarity mappings as probabilistic and hypothetical relations among ontology elements.


A. G. Cohn, D. C. Hogg, R. Möller, and B. Neumann, editors. Logic and Probability for Scene Interpretation. Dagstuhl Seminar Proceedings, 2008.
Bibtex entry


J. Faddoul, N. Farsinia, V. Haarslev, and R. Möller. A Hybrid Tableau Algorithm for ALCQ. In Proceedings of the 18th European Conference on Artificial Intelligence (ECAI 2008), Patras, Greece, July 21-25, pages 725–726, 2008.
Bibtex entry  Paper (PDF)

Abstract

We propose an approach for extending a tableau-based satisfiability algorithm by an arithmetic component. The result is a hybrid satisfiability algorithm for the Description Logic ALCQ which extends ALC with qualified number restrictions. The hybrid approach ensures a more informed calculus which, on the one hand, adequately handles the interaction between numerical and logical restrictions of descriptions, and on the other hand, when applied is a very promising framework for average case optimizations.


J. Faddoul, N. Farsinia, V. Haarslev, and R. Möller. A Hybrid Tableau Algorithm for ALCQ. In Proceedings of the 2008 International Workshop on Description Logics (DL-2008), Dresden, Germany, May 13-16, 2008.
Bibtex entry  Paper (PDF)

Abstract

We propose an approach for extending a tableau-based satisfiability algorithm by an arithmetic component. The result is a hybrid satisfiability algorithm for the Description Logic ALCQ which extends ALC with qualified number restrictions. The hybrid approach ensures a more informed calculus which, on the one hand, adequately handles the interaction between numerical and logical restrictions of descriptions, and on the other hand, when applied is a very promising framework for average case optimizations.


Jocelyne Faddoul, Volker Haarslev, and Ralf Möller. Hybrid Reasoning for Description Logics with Nominals and Qualified Number Restrictions. Technical report, Institute for Software Systems (STS), Hamburg University of Technology, Germany, 2008. See http://www.sts.tu-harburg.de/tech-reports/papers.html.
Bibtex entry  Paper (PDF)


Miguel Garcia and Ralf Möller. Incremental evaluation of OCL invariants in the Essential MOF object model. In Thomas Kühne, Wolfgang Reisig, and Friedrich Steimann, editors, Modellierung 2008, volume 127 of GI-Edition Lecture Notes in Informatics, pages 11–26, 2008.
Bibtex entry  Paper (PDF)

Abstract

Incremental evaluation of OCL invariants in the Essential MOF object model Miguel Garcia, Ralf Moeller Institute for Software Systems (STS) Hamburg University of Technology (TUHH), 21073 Hamburg http://www.sts.tu-harburg.de/~mi.garcia Abstract: The management of metamodels is supported by runtime environments that enforce the well-formedness of (meta-)model instances. Beyond this basic functionality, additional capabilities are needed in order to successfully establish a toolchain for Model-Driven Software Engineering. We focus on two such capabilities: transactions and efficient evaluation of invariants, not in the usual context of databases but for main-memory runtime engines, an area where no previous work has addressed the combination of Essential MOF + OCL. The realization of this infrastructural support proves feasible but requires a careful design to accomodate the expressiveness of OCL.


V. Haarslev and R. Möller. On the Scalability of Description Logic Instance Retrieval. Journal of Automated Reasoning, 41(2):99–142, 2008.
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. The article introduces and evaluates optimization techniques for the instance retrieval problem w.r.t. the description logic SHIQ(D), which covers large parts of the Web Ontology Language (OWL). We demonstrate that sound and complete query engines for OWL-DL can be built for practically significant query classes. Experience with ontologies derived from database content has shown that it is often necessary to effectively solve instance retrieval problems with respect to huge amounts of data descriptions that make up major parts of ontologies. We present and analyze the main results about how to contribute to this kind of scalability problem.


V. Haarslev and R. Möller. The revival of structural subsumption in tableau-based description logic reasoners. In Proceedings of the 2008 International Workshop on Description Logics (DL-2008), 2008.
Bibtex entry  Paper (PDF)

Abstract

The paper summarizes our experiences with optimization techniques for well-known tableau-based description logic reasoning systems, and analyzes the performance of very simple techniques to cope with Tboxes whose bulk axioms just use a less expressive language such as ELH, whereas some small parts of the Tbox use a language as expressive as SHIQ. The techniques analyzed in this paper have been tested with RacerPro, but they can be embedded into other tableau-based reasoners such as, e.g., Fact++ or Pellet in a seamless way.


R. Möller and B. Neumann. Ontology-based Reasoning Techniques for Multimedia Interpretation and Retrieval. In Semantic Multimedia and Ontologies : Theory and Applications, pages 55–98. 2008.
Bibtex entry  Paper (PDF)


T. Näth and R. Möller. ContraBovemRufum: A System for Probabilistic Lexicographic Entailment. In Proc. 21st International Workshop on Description Logics (DL2008), 2008.
Bibtex entry


S. Espinosa Peraldi, A. Kaya, S. Melzer, and R. Möller. On Ontology Based Abduction for Text Interpretation. In A. Gelbukh, editor, Proc. of 9th International Conference on Intelligent Text Processing and Computational Linguistics (CICLing-2008), number 4919 in LNCS, pages 194–205. Springer, 2008.
Bibtex entry  Paper (PDF)

Abstract

Text interpretation can be considered as the process of extracting deep-level semantics from unstructured text documents. Deep-level semantics represent abstract index structures that enhance the precision and recall of information retrieval tasks. In this work we discuss the use of ontologies as valuable assets to support the extraction of deep-level semantics in the context of a generic architecture for text interpretation.


S. Wandelt and R. Möller. Island Reasoning for ALCHI Ontologies. In C. Eschenbach and M. Gr"uninger, editors, Proceedings of the Fifth International Conference on Formal Ontology in Information Systems (FOIS'08), pages 164–177. IOS Press, 2008.
Bibtex entry  Paper (PDF)

Abstract

In the last years, the vision of the Semantic Web fostered the interest in reasoning over ever larger sets of assertional statements in ontologies. It is easily conjectured that, soon, real-world ontologies will not fit into main memory anymore. If this was the case, state-of-the-art description logic reasoning systems cannot deal with these ontologies any longer, since they rely on in-memory structures. We propose a way to overcome this problem by reducing instance checking for an individual in an ontology to a (usually small) relevant subset of assertional axioms. This subset can then be processed by state-of-the-art description logic reasoning systems to perform sound and complete instance checks for the given individual. We think that this technique will support description logic systems to deal with the upcoming large amounts of assertional data.


M. Wessel and R. Möller. Software Abstractions for Description Logic Systems. In Proceedings of the 5th European Lisp Workshop (ELW'08), 2008.
Bibtex entry  Paper (PDF)

Abstract

We explain the basics of description logics and tableau provers for reasoning with them. The implementation of tableau provers is a complicated matter and demanding from a software engineering point of view. We present and discuss their implementation in COMMON LISP and motivate and introduce some novel software abstractions for description logic system construction, which are embodied in the MIDELORA toolkit / framework.


Acknowledgments
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