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.
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