International Master Programme in Computational Logic at TU Dresden, WS 2005/2006

Knowledge Representation and Reasoning for the Semantic Web

Teachers: Dr. Pascal Hitzler and M.Sc. Markus Krötzsch
both currently at AIFB, University of Karlsruhe.

Prerequisites: Passed exams in ICL and FCLP.
Duration: 3 cr (2 SWS)
Dates: The seminar will be held as a block on Friday, January 20th 2006, starting at 1pm in Room 357. There are just three talks, so the seminar will probably not take longer than until 6pm.



With amazing speed, the World Wide Web has become a widely spread means of communication and information sharing. Today, it is an integral part of our society, and will continue to grow. However, most of the available information cannot easily be processed by machines, but has to be read and interpreted by human readers. In order to overcome this limitation, a world-wide research effort is currently being undertaken, following the vision spelled out by Tim Berners-Lee et al. (2001), to make the contents of the World Wide Web accessible, interpretable, and usable by machines. The resulting technology is commonly being referred to as the Semantic Web.

A key idea of the effort is that web content shall be provided with conceptual background – often referred to as ontologies – which allows machines to put the information into a context in order to make it interpretable. In 2004, after having established RDF and RDFSchema as basic syntax, the description-logic-based Web Ontology Language OWL has been recommended by the World Wide Web Consortium (W3C) as foundational ontology reprepresentation language. For practical applications, it is apparent that extensions of OWL will be needed, and research efforts are currently under way to investigate this.

In this seminar, we will study basic and advanced means for semantic web knowledge representation and reasoning, including e.g. RDF(S), OWL and various proposed extensions of it, e.g. by uncertainty, commensense, or paraconsistent reasoning techniques, rule-based languages and language extensions, available reasoning systems, their background theories, and means to achieve scalability.

Registration and requirements

Scheduled topics

The following table gives the topics that will be presented (in their intended order) and the respective speakers. The students written summaries and any other course material will also be published here when available.

Topic and references Speaker/Material
KAON2 Algorithms (non-tableau reasoning with description logics)
  • U. Hustadt, B. Motik, U. Sattler. Reasoning in Description Logics with a Concrete Domain in the Framework of Resolution. Proceedings of the 16th European Conference on Artificial Intelligence (ECAI 2004), August, 2004, Valencia, Spain, pages 353–357
  • U. Hustadt, B. Motik, U. Sattler. Reducing SHIQ Descrption Logic to Disjunctive Datalog Programs. Proceedings of the 9th International Conference on Knowledge Representation and Reasoning (KR2004), June 2004, Whistler, Canada, pages 152–162
Christelle Braun

PDFslides (448KB)
Paraconsistency for Description Logics (Diploma Thesis) Andreas Lang

PDFslides (686KB)
Fuzzy Ontologies
  • U. Straccia. Towards a Fuzzy Description Logic for the Semantic Web (Preliminary Report). In Proceedings of the 2nd European Semantic Web Conference (ESWC-05), 2005.
  • U. Straccia. Transforming Fuzzy Description Logics into Classical Description Logics. In Proceeedings of the 9th European Conference on Logics in Artificial Intelligence (JELIA-04), 2004.
Dzung Dinh-Khac

PDFslides (104KB)

Remaining topics

At the moment, the following topics are still available. Most of the given references for further reading should be available online, for example on the homepages of the respective authors. Please send an email to Markus Krötzsch if you are interested.

The topics focus on ontology languages that have emerged from research on the Semantic Web and related technologies. These languages usually provide a formal (often logical) semantics, and both their theoretical power and their practical implementation are are of great importance. Many of the topics relate to recent developments and extensions within the area and are of high interest to current research. Please contact us if you have any questions.

Topic and references Speaker
Approximate reasoning with ontologies
  • P. Hitzler, D. Vrandecic. Resolution-Based Approximate Reasoning for OWL DL. In Proceedings of the 4th International Semantic Web Conference, Galway, Ireland, November 2005. November 2005. To appear.
  • P. Groot, H. Stuckenschmidt, H. Wache. Approximating Description Logic Classification for Semantic Web Reasoning. In Proceedings of the European Semantic Web Conference (ESWC 2005): 318–332.
Probabilistic ontologies
  • D. Koller, A.Y. Levy, and A. Pfeffer. P-classic: A tractable probablistic description logic. In Proceedings of the AAAI 14th National Conference on Artificial Intelligence, 390–397, 1997.
  • Z. Ding and Y. Peng. A probabilistic extension to ontology language OWL. In Proceedings of the 37th Hawaii International Conference on System Sciences (HICSS), 2004.
  • R. Giugno and T. Lukasiewicz. P-shoq(d): A probabilistic extension of shoq(d) for probabilistic ontologies in the Semantic Web. In JELIA '02: Proceedings of the European Conference on Logics in Artificial Intelligence, 86–97. Springer-Verlag, 2002.
  • J. Davies, A. Duke, and Y. Sure. Ontoshare – a knowledge management environment for virtual communities of practice. In Proceedings of the 2nd International Conference on Knowledge Capture (K-CAP2003), 23-26 October 2003, Florida, USA, 20–27. ACM Press, 2003.
  • M. Holi and E. Hyvönen. Modeling Degrees of Overlap in Semantic Web Ontologies. Submitted, 2005.
Fuzzy Ontologies
  • U. Straccia. Towards a Fuzzy Description Logic for the Semantic Web (Preliminary Report). In Proceedings of the 2nd European Semantic Web Conference (ESWC-05), 2005.
  • U. Straccia. Transforming Fuzzy Description Logics into Classical Description Logics. In Proceeedings of the 9th European Conference on Logics in Artificial Intelligence (JELIA-04), 2004.
Web Rule Language (WRL)
Implementing OWL DL with Nominals
  • I. Horrocks, U. Sattler. A Tableaux Decision Procedure for SHOIQ. In Proceedings of Nineteenth International Joint Conference on Artificial Intelligence, IJCAI-05, 2005.
OWL und Answer Set Programming
  • Th. Eiter, Th. Lukasiewicz, R. Schindlauer, H. Tompits. Combining Answer Set Programming with Description Logics for the Semantic Web. Proceedings of the 9th International Conference on Principles of Knowledge Representation and Reasoning (KR 2004), June 2–5, Whistler, British Columbia, Canada, 2004, pages 141–151
Autoepistemic Extensions of OWL
  • R. Rosati. Autoepistemic Description Logics. AI Communications, volume 11(3–4), pages 219–221, 1998.

Hints and advice

What is expected from you?

You are supposed to give a presentation lasting 60 minutes, and to deliver a manuscript before your presentation.

The presentation should cover a comprehensive overview or a detailed discussion of some aspects of the literature which is available on the topic chosen. You can decide to make a selection from the material if you think it is appropriate. You can include material from other publications if you think this is good. When in doubt, discuss it with us.

The manuscript (approx. 10 pages, no strict upper limit) should present the same material as the talk.

A very good seminar talk …

A very good manuscript …

Improving your presentation and manuscript

Help for using LaTeX

Scientific manuscripts are probably most easily (and most beautifully) created using the free typesetting system LaTeX, and we strongly encourage its use. The initial overhead of getting acquainted with the system should pay off, since it is also very suitable to write project or Master's thesis (and scientific articles and books, if you have plans to do this).

LaTeX is freely available online for most operating systems (e.g. for Linux [any distribution has this pre-packaged, but you can also install it manually], MacOS X and MS Windows). LaTeX-documents are – similarly to HTML – written in a simple markup language and then transformed into PS or PDF documents. A very good (and not too long) first introduction is

Further helpful refernences are found in the Wikipedia article on LaTeX. You can also contact us if you have concrete problems with typesetting.

About the lecturers

Dr. Pascal Hitzler was a postdoctoral researcher at Prof. Steffen Hölldobler's research group at TU Dresden until July 2004. He then joined the research group of Prof. Rudi Studer at the University of Karlsruhe as a research project leader, and is involved in EU and BMBF-funded research projects on Semantic Web technologies, including KnowledgeWeb, SEKT, and SmartWeb. He has a notable publication record including theoretical and practical issues of computational logic.

M.Sc. Markus Krötzsch obtained a Master in Computational Logic at TU Dresden in March 2005. He is currently a PhD student of Prof. Rudi Studer and working under the supervision of Pascal Hitzler.