[DL] Description Logics for Conceptual Design, Information Access, and Ontology Integration: Research Trends

Tutorial Information
lecturer: Enrico Franconi, Department of Computer Science, University of Manchester, UK

tutorial description:
In recent years, data and knowledge base applications have progressively converged towards integrated technologies that try to overcome the limits of each single discipline. Research in Knowledge Representation (KR) originally concentrated around formalisms that are typically tuned to deal with relatively small knowledge bases, but provide powerful deduction services, and the language to structure information is highly expressive; research on formal languages for ontologies was originated from KR. In contrast, Information Systems and Database research mainly dealt with efficient storage and retrieval with powerful query languages, and with sharing and displaying large amounts of (multimedia) documents. However, data representations were relatively simple and flat, and reasoning over the structure and the content of the documents played only a minor role.

This distinction between the requirements in Knowledge Representation and Databases is vanishing rapidly. On the one hand, to be useful in realistic applications, such as the applications in the semantic web, a modern ontology KR system must be able to handle large data sets, and to provide expressive query languages. This suggests that techniques developed in the DB area could be useful for ontologies. On the other hand, the information stored on the web, in digital libraries, and in data warehouses is now very complex and with deep semantic structures, thus requiring more intelligent modelling languages and methodologies, and reasoning services on those complex representations to support design, management, retrieval, and integration. Therefore, a great call for an integrated view of Knowledge Representation and Database technologies is emerging.

Description Logics (DL) [BN02] are a very promising research area in KR with applications in DBs (see www.dl.kr.org). The main effort of the research in DL is in providing both theories and systems for expressing structured knowledge and for accessing and reasoning with it in a principled way [CDLN02,Don02]. Recently, basic progress has been made by establishing the theoretical foundations for the effective use of DL in information systems [Bor95,BLR02]. DL offer promising formalisms for solving several problems concerning Conceptual Data Modelling and Ontology Design (see, e.g., [CLN98,BB02], or the OIL and DAML+OIL efforts [FHvH+00,IH02]), Intelligent Information Access and Query processing (see, e.g., [BB93,LR98,BNP00,Fra00]), and Information Integration (see, e.g., [CGL+98,JQC+00,MIKS00,]).

This tutorial will have a popular style showing research trends, rather than a strictly theoretical one. Its aim is to let the audience understand why DL and DB technologies could be useful to semantic web research and applications, and it will mostly make use of examples. Nonetheless, precise links to the important theoretical results and to the relevant references will be given.

In the tutorial I will argue that good Conceptual Modelling and Ontology Design is required to support powerful Query Management and to allow for semantic based Information Integration. Therefore, the tutorial has been structured into three parts:

  • In the first part (described in Section 2), an extended ontology language and a methodology for conceptual and ontology design will be introduced.
  • In the second part (described in Section 3), the query management problem in the presence of the previously devised conceptual model will be considered: a global framework will be introduced, together with various basic tasks involved in information access.
  • In the last part (described in Section 4), general issues about ontology integration will be presented.

tutorial material:

useful links:

  • The official Description Logics page
  • The Introduction to Description Logics online course page
  • The Description Logic Handbook: Theory, Implementation and Applications. Cambridge University Press, 2002. ISBN 0521781760. Edited by F. Baader, D. Calvanese, D. McGuinness, D. Nardi, P. F. Patel-Schneider. Contributors; D. Nardi, R.J. Brachman, F. Baader, W. Nutt, F.M. Donini, U. Sattler, D. Calvanese, R. Molitor, G. De Giacomo, R. Kuesters, F. Wolter, D.L. McGuinness, P.F. Patel-Schneider, R. Moeller, V. Haarslev, I. Horrocks, A. Borgida, C. Welty, A. Rector, E. Franconi, M. Lenzerini, R. Rosati.

Tutorial version 1 ( Last modified: Mon Jun 10 02:03:49 BST 2002 )

  • Course material prepared by me may contain errors: please, help me in making it better.
  • Parts of the above course material have been inspired by many contributors in the DL field: thanks to them all!
  • Online papers may be copyrighted and they are available for evaluation purposes only. People are invited to contact the authors or the publishers for permissions.