Description Logics

Description Logics

Technische Universität Dresden
Institut für Theoretische Informatik
Lehrstuhl für Automatentheorie

Prof. Franz Baader

Announcements

The lectures on 14th of June and 21st of June are cancelled. Thus the tutorial on the 15th of July is cancelled as well.

Course Description

Description Logics (DLs) are a successful family of logic-based knowledge representation formalisms, which can be used to represent the conceptual knowledge of an application domain in a structured and formally well-understood way. They are employed in various application domains, such as natural language processing, configuration, and databases, but their most notable success so far is the adoption of the DL-based language OWL as standard ontology language for the semantic web. This course concentrates on designing and analyzing reasoning procedures for DLs. After a short introduction of predecessor formalisms such as semantic networks and frames, it will introduce the basic features of DLs such as concepts, TBoxes and ABoxes, and basic inference problems such as the subsumption and the instance problem. The course introduces techniques for solving these problems based on tableau-algorithms, automata, and other approaches. Also, the complexity of standard DLs is analyzed, identifying expressive DLs for which reasoning is expensive in the worst case, but still manageable in practice, and lightweight DLs for which reasoning is tractable.

Organization

The lecture takes place in room E05: Tuesday and Thursday always at 16:40-18:10 (DS6). In addition, some lectures will take place in room E05 on Monday 16:40-18:10 (DS6) as substitutes for lectures that cannot be held during the regular Tuesday/Thursday slot. The exact distribution of lectures and tutorials is displayed here:

	Monday	Tuesday	Wednesday	Thursday	Friday
12.4 - 16.4		Lecture	Lecture	Lecture
19.4 - 23.4	Tutorial Exercise sheet 1	Lecture	Lecture	Lecture
26.4 - 30.4	Lecture	Lecture	Tutorial Exercise sheet 2	Lecture
03.5 - 07.5	Lecture	Lecture		Lecture
10.5 -14.5		Tutorial Exercise sheet 3	Tutorial Exercise sheet 4
17.5 - 21.5	Lecture	Lecture	Tutorial Exercise sheet 5	Lecture
24.5 - 28.5
31.5 - 04.6	Lecture	Lecture	Tutorial Exercise sheet 6	Lecture
07.6 - 11.6	Lecture	Tutorial Exercise sheet 7	Lecture	Lecture
14.6 - 18.6	~~Lecture~~ (cancelled!)	Lecture	Tutorial Exercise sheet 8	Lecture
21.6 - 25.6	~~Lecture~~ (cancelled!)	Lecture	Tutorial Exercise sheet 9	Lecture
28.6 - 02.7			Tutorial Exercise sheet 10
05.7 - 09.7			Tutorial Exercise sheet 11
12.7 - 16.7			Tutorial Exercise sheet 12 and 38) from sheet 11	~~Tutorial~~ (cancelled!)
19.7 - 23.7

Exercises

The first exercise takes place on Monday 19th of April 16:40-18:10 (DS6), Room E05. From April 21st on, the exercise group takes place every Wednesday 16:40-18:10 (DS6) in Room E05 by default. Exceptions are listed in the table above. The tutorial is held by Anni-Yasmin Turhan. Every week, an exercise sheet is made available for download from this webpage from the table above.

Lecture Material

A script of the lecture is not available and students are strongly recommended to copy what is written on the blackboard. We provide the slides for the introductory sessions:

Motivation chapter
Chapter 2.
Chapter 3 — now with Theorem 3.10b and revised!
Chapter 4

We also provide scanned versions of the example slides used in the session about frames and semantic networks:

Frog example: slide 1, slide 2, slide 3.
Restaurant example: slide 1.

Credits / Examinations

Computational logic students can earn 9 credits by attending this lecture. The lecture can be used for the modules KRAI, IT, TCSL. In order to get the credits, CL students have to meet both of the following two obligations:

present at least four exercises in front of the exercise group;
pass an oral examination at the end of the term.

Computer Science students are not obliged to present exercises, but are invited to do so.

Literature

F. Baader, D. Calvanese, D. McGuinness, D. Nardi, and P. F. Patel-Schneider, editors. The Description Logic Handbook: Theory, Implementation, and Applications. Cambridge University Press, 2003.
F. Baader and C. Lutz. Description Logic. In P. Blackburn, J. van Benthem, and F. Wolter, editors, The Handbook of Modal Logic, pages 757 - 820.
Franz Baader. Description Logics. In Reasoning Web: Semantic Technologies for Information Systems, 5th International Summer School 2009, volume 5689 of Lecture Notes in Computer Science, pages 1--39. Springer-Verlag, 2009.

Anni-Yasmin Turhan