Komplexpraktikum/Project "Automated Reasoning in Logical Formalisms" in WS 2003/04


Initial meeting
takes place on October 17 at 11:10 (3. DS) in Room 454. Attending the initial meeting is mandatory for participation in the praktikum/project.
People who want to participate in the praktikum/project, but have serious reasons to not attend the initial meeting, please send an email until April 8.

Position in curriculum
- Diplomstudiengang Informatik (Diplom- und Bakkalaureatsabschlu▀), ab 5. Semester ;Wahlpflichtveranstaltung (-/-/4)
- Course of studies Computation Logic; project (12 credits); module TCSL

Prerequisites
for computer scientists: Pflichtvorlesung "Grundlagen der Theoretischen Informatik"

Organisation
- An initial meeting is held at the beginning of the semester (see above). In this meeting, a brief presentation of the available topics will be given (see below). Students then have the opportunity to choose a topic to work on.
- Each student is assigned a tutor, depending on the topic chosen. During the semester, there will be regular meetings of the student and his tutor.
- The results of the praktikum/project will be presented at the end of the semester in a talk given by the student. Time and date are yet to be fixed.

Language
The language of the initial meeting is English. Concerning the final presentations, students may choose to present their work in German or in English.

Participants Duties
The participants are expected to read the relevant literature, and to discuss it with their tutor in order to become acquainted with the topic chosen. The required implementation work should be carried out in a structured way, and has to be documented appropriately. If a topic is shared by two or more participants, acquiring team-working skills is another goal of the project. The results of the project have to be described in a project paper (~15 pages) and presented in a 30 minutes talk at the end of the semester.

Topics

Some of the topics can be worked on by more than one student. Further topics will be added in due course.

(1) Implementation of optimized ALC-ALE Approximations
Approximation is a new reasoning service for description logics that has recently cought the attention of researchers. The purpose of this project is to enhance the existing LISP implementation of approximation for the description logics ALC and ALE by integrating two optimization techniques: (1) a special treatment of certain well-behaved (so called "nice") concepts and (2) implementation of the so-called "lazy unfolding" of acyclic TBoxes. Both implementations should then also be evaluated and compared.
Literature: Tutor: Anni-Yasmin Turhan.

(2) Semantic Annotation of Webpages and description of the experiences made.
The semantic web is a current initiative for generating new W3C standards that allow to annotate WWW pages with a machine-understandable description of their content. Obviously, such a semantic annotation would facilitate the implementation of more exact search engines and allow the deployment of all kinds of autonomous agents on the web. The purpose of this project is to semantically annotate the web pages of the chair for automata theory using the currently emerging OWL standard, and to give a detailed discussion of the experiences made.
Literature:
  • S. Bechhofer, L. Carr, C. Goble, S. Kampa, T. Miles-board. The Semantics of Semantic Annotation. COHSE: Conceptual Open Hypermedia Service. Annotation for the Semantic Web eds. Siegfried Handschuh and Steffen Staab. IOS Press, Frontiers in Artifical Intelligence and Applications. Vol 96. 2003.
  • S. Bechhofer, I. Horrocks, C. Goble, and R. Stevens. OilEd: a reason-able ontology editor for the semantic web. In Proc. of the Joint German Austrian Conference on AI, number 2174 in Lecture Notes In Artificial Intelligence, pages 396-408. Springer-Verlag, 2001.
Tutor: Carsten Lutz,

(3) Concept generator for description logics.
to evaluate the quality of imlemented DL reasoning systems, it is very useful to generate a large amount of formulas with certain characteristics. The goal of this project is to implement a generator for description logic concepts (i.e., formulas) that takes several parameters, such as nesting depth and number of atomic concepts, and randomly generates a set of concepts in accordance with the input parameters.
Literature:
  • Ian P. Gent and Toby Walsh. Beyond NP: The QSAT Phase Transition. Proceedings of AAAI-99, 1999.
  • I. Horrocks, P. F. Patel-Schneider, and R. Sebastiani. An analysis of empirical testing for modal decision procedures. Logic Journal of the IGPL, 8(3):293-323, 2000.
Tutor: Jan Hladik

(4) Implementation of a matching algorithm for the Description Logic ALN.
A matching problem comprises a concept description and a so-called concept pattern, i.e., a concept description with variables. Matching a concept pattern against a concept description means finding a substitution of the occurring variables by concept descriptions such that the original concept description is subsumed by the instantiated concept pattern.
Since matching in the Description Logic ALN is theoretically well-examined this topic focusses on the implementation of the relevant algorithm in LISP and on the evaluation w.r.t. run-time behaviour.
Literature:
  • F. Baader, R. Küsters, A. Borgida, and D. McGuinness. Matching in Description Logics. Journal of Logic and Computation, 9(3):411-447, 1999.
  • S. Brandt. Matching under Side Conditions in Description Logics. Diploma thesis, RWTH Aachen, Germany, 2000.
  • Guy L., Jr. Steele. Common Lisp: The Language.
Tutor: Sebastian Brandt

(5) Unification in Equational Theories.
An important problem in the area of Term Rewriting is unification of two terms modulo an equational theory. This problem is semi-decidable in general. There is a complete procedure to solve E-unification problems, but this procedure does not halt for all inputs. On the other hand, if we look for a solution with an equational proof of a given length n and E is non-subterm-collapsing, then the E-unification procedure becomes a decision procedure.
The project requires implementing the procedure that takes as input an equational theory, a goal equation and a natural number n, and gives as output an equational proof of length n of the solved goal, if it exists, or a negative answer if it does not exist.
Literature:
  • B. Morawska. Completeness of E-unification with eager Variable Elimination. LTCS-Report 03-03, Chair for Automata Theory, Institute for Theoretical Computer Science, Dresden University of Technology, Germany, 2003. See http://lat.inf.tu-dresden.de/research/reports.html
Tutor: Barbara Morawska


Barbara Morawska