invited talk: Engineering of logics for the content-based
July 24th 11:00-12:00 in auditorium 3
and transfer of information as well as interfaces for
accessing this information have undergone a remarkable evolution.
Nevertheless, information systems are still not `intelligent' in the sense
that they `understand' the information they store, manipulate, and present
to their users. A case in point is the world wide web and search engines
allowing to access the vast amount of information available there.
Web-pages are mostly written for human consumption and the mark-up provides
only rendering information for textual and graphical information. Search
engines are usually based on keyword search and often provide a huge number
of answers, many of which are completely irrelevant, whereas some of the
more interesting answers are not found. In contrast, the vision of a
`semantic web' aims for machine-understandable web resources, whose content
can then be comprehended and processed both by automated tools, such as
search engines, and by human users.
The content-based representation
of information requires representation formalisms with a well-defined
formal semantics since otherwise there cannot be a common understanding of
the represented information. This semantics can elegantly be provided by a
translation into an appropriate logic or the use of a logic-based formalism
in the first place. This logical approach has the additional advantage that
logical inferences can then be used to reason about the represented
information, thus detecting inconsistencies and computing implicit
information. However, in this setting there is a fundamental tradeoff
between the expressivity of the representation formalism on the one hand,
and the efficiency of reasoning with this formalism on the other hand.
This motivates the `engineering of logics', i.e., the design of logical
formalisms that are tailored to specific representation tasks. This also
encompasses the formal investigation of the relevant inference problems,
the development of appropriate inferences procedures, and their
implementation, optimization, and empirical evaluation. Another important
topic in this context is the combination of logics and their inference
procedures since a given application my require the use of more than one
specialized logic. The talk will illustrate this approach with the example
of so-called Description Logics and their application as ontology languages
for the semantic web.
Franz Baader is professor for Theoretical Computer Science at the RWTH
Aachen, Germany. 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). He has participated
in ESPRIT Basic Research Projects and Working Groups, and he currently
has several project grants from the German national science foundation (DFG).
He has been in the program committee of various national and international
conferences in the areas automated deduction, artificial intelligence,
knowledge representation, and logics, has organized many international
and is in the editorial board of three electronic AI journals. He has
about 80 refereed articles in major journals and conferences.