http://www.inf.unibz.it/~calvanese/teaching/2007-11-ISWC-tutorial-obda/
Ontology-based Data Access
Tutorial at the 6th International Semantic Web Conference
(ISWC 2007)
Busan, South Korea, November 11-15 2007
Diego
Calvanese
KRDB Research Centre
Free University of Bozen-Bolzano
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Domenico
Lembo
Dipartimento di Informatica e Sistemistica
La Sapienza Università di Roma
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Summary
Many organizations nowadays face the problem of accessing existing data
sources by means of mechanisms that are sufficiently expressive without
compromising efficiency. Ontologies allow one to describe the domain of
interest of an information system at a high level of abstraction, and are
widely considered as a suitable formal tool for sophisticated data access.
In this tutorial we provide a comprehensive understanding of the problem of
ontology-based data access, both from the theoretical and from the practical
points of view. We address several problems that are crucial in this context:
- the trade-off between the expressive power of the
ontology language and the efficiency of computing answers to
queries;
- the processing of queries posed over the ontology by
accessing the data stored in the sources;
- the impedance mismatch between the abstract objects at the
ontology level and the concrete data values stored in data sources;
- the integration of multiple data sources;
- the mutual inconsistency of data and constraints in the ontology.
We will present solutions to these problems based on recent research results
in the area of tractable Description Logics. We will provide also a
``hands-on'' experience with the QuOnto system, which will allow participants
to familiarize with state-of-the-art technology in ontology-based data
access.
General info
Aims:
The tutorial aims at providing a deep comprehension about the problem of
ontology-based data access, a critical issue for Semantic Web applications that
is recently receiving a growing attention. It addresses both theory and
practice on this topic, proposing a formal study of the problem (formalization,
languages, algorithms, and complexity characterization) and a ``hands-on''
session using a tool for reasoning over ontologies suited for ontology-based
data access.
Presentation style:
lectures with slides and hands-on session
Target audience:
researchers, Ph.D. Students, and practitioners
Prerequisite knowledge:
basic knowledge in first-order logic and relational databases; background in
Description Logics is preferable, but not strictly necessary
Tutorial duration: full day
Outline of the tutorial content and schedule
(draft)
- Introduction to Ontology-Based Data Access
- Introduction to ontologies
- Ontology languages
- Description Logics and the DL-Lite family
- A gentle introduction to DLs
- DLs as a formal language to specify ontologies
- Queries in Description Logics
- The DL-Lite family of tractable DLs
- Reasoning in the DL-Lite family
- TBox reasoning
- TBox and ABox reasoning
- Complexity of reasoning in Description Logics
- Linking data to ontologies
- The Description Logic Dl-Lite_A
- Connecting ontologies to relational data
- Hands-on session
- A practical session with Mastro, a system for Ontology-Based Data
Access through DL-Lite
teaching page of Diego Calvanese
Last modified:
Monday, 7-Sep-2009 8:31:25 CEST