JAIST先端レクチャー・シリーズ（第6回）の開催について
来る3月13日（火）に，下記の講演会を開催します。ホットなトピックスについての分かりやすい講演ですので，多数の皆様（特に学生の方）に参加
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We would like to inform you of the JAIST Advanced Lecture Series 6 by
a guest professor of JAIST as follows.
DATE：March 13, 2012 15:00-17:00
PLACE：JAIST KS Lecture Hall
TITLE：“Ontology-Based Data Access and Constraint Satisfaction”
SPEAKER：Prof. Frank Wolter
(Univ. of Liverpool, Guest Professor of JAIST)
ABSTRACT：
In recent years, the use of ontologies to access instance data has
become increasingly popular. The general idea is that an ontology
provides a vocabulary or conceptual model for the application domain,
which can then be used as an interface for querying instance data and
to derive additional facts.
In this presentation, I will first introduce ontology-based data
access (OBDA). I will focus on ontologies given in description logics
or, equivalently, the web ontology language OWL. I will then establish
a very close link between OBDA and constraint satisfaction problems
with finite templates (CSP). Rather surprisingly, for the basic
description logic ALC (=modal logic) OBDA and CSP turn out to be
essentially equivalent. This result has a large number of consequences
for ALC and OBDA in general.
I will focus on the following non-uniform complexity problem: what is
the complexity of query answering for a fixed ontology? I will present
general conditions under which this problem is in PTime and,
respectively, coNP-hard. Using the CSP connection is shown that for
ALC there is a P/coNP dichotomy for conjunctive query answering if, and
only if, the famous, and still open, Feder/Vardi dichotomy conjecture
for CSP holds.
The talk is based on joint work with Carsten Lutz.