DeReLoP -
Automating Defeasible Reasoning with Logic Programming

Jürgen Dix (head)
Frieder Stolzenburg
Universität Koblenz-Landau, Germany

Carlos I. Chesñevar
Pablo R. Fillottrani
Alejandro J. García
Guillermo R. Simari (head)
Universidad Nacional del Sur, Bahia Blanca, Argentina

This research was supported by the German-Argentinian program on scientific and technological cooperation, funded by the Bundesministerium für Bildung und Forschung in Germany and the Secretaría de Ciencia y Tecnología in Argentina

Objectives and Project Description

Both groups involved in this project - the AI research group at the university of Koblenz, Germany and Prof. G. Simari's group at the Southern University at Bahia Blanca, Argentina - are working in the broad area of knowledge representation and on applications to the development of knowledge-based systems. While the Bahia Blanca group defined some theoretical frameworks for Circumscription, Belief Revision and Plausible Reasoning, the Koblenz group developed and implemented systems for disjunctive logic programs, and for classical first order logic - the PROTEIN system. The DeReLoP-project has three main branches where we expect mutual benefits from each group:

Current Work and Perspectives

The current work focuses on Agent Programming. Here Bahia Blanca developed and implemented an abstract machine for handling defeasible reasoning and to be used for agent programming. The Koblenz group is currently doing a particular application of a framework of multiple agents, namely designing a program for playing soccer: multiple, fast moving robot agents in a dynamic, non-deterministic environment in the RoboLog project. Koblenz is also involved in a project on Heterogenous Active Agents, where logic programming technology is heavily used for modelling the behaviour of software agents - the IMPACT project. The most promising topics for future work seem to be:

Publications

Biographies of Project Leaders

Jürgen Dix is an Assistant Professor in the Department of Computer Science at University of Koblenz-Landau in Koblenz. He got his PhD in 1992 at Karlsruhe university and his habilitation at TU Vienna in 1996. He is co-editor of 6 proceedings in the Springer Lecture Notes of Artificial Intelligence series and of two special issues in Annals of Math and AI, co-author of a monograph on Nonmonotonic Reasoning, and author of more than 30 articles in Handbooks and Journals. He is member of the AI group in Koblenz (headed by Prof. U. Furbach) and heads (joint with Prof. U. Furbach) an international project on disjunctive logic programming. He is currently (1999) a Visiting Assistant Professor at the Department of Computer Science in College Park, Maryland.

References

BD98
Stefan Brass and Jürgen Dix.
Characterizations of the Disjunctive Well-founded Semantics: Confluent Calculi and Iterated GCWA.
Journal of Automated Reasoning, 20(1):143-165, 1998.

BDK97
Gerd Brewka, Jürgen Dix, and Kurt Konolige.
Nonmonotonic Reasoning: An Overview.
CSLI Lecture Notes 73. CSLI Publications, Stanford, CA, 1997.

DFN99
Jürgen Dix, Ulrich Furbach, and Ilkka Niemelä.
Nonmonotonic Reasoning: Towards Efficient Calculi and Implementations.
In Andrei Voronkov and Alan Robinson, editors, Handbook of Automated Reasoning. Elsevier-Science-Press, to appear 1999.

DS98
Jürgen Dix and Frieder Stolzenburg.
A framework to incorporate non-monotonic reasoning into constraint logic programming.
Journal of Logic Programming, 37(1-3):47-76, 1998.
Special Issue on Constraint Logic Programming. Guest editors: Kim Marriott and Peter J. Stuckey.

DSP00
Jürgen Dix, VS. Subrahmanian, and George Pick.
Meta Agent Programs.
Journal of Logic Programming, to appear, 2000.

Guillermo Simari is a Full Professor in the Department of Computer Science at Universidad Nacional del Sur in Bahia Blanca. He got his PhD in 1989 at Washington University (R. Loui). He is heading a group of 10 students working on their Master and PhD Theses. His research interests are in Knowledge Representation and Reasoning and Logic Programming, especially in the connection between the two areas.

References

FS97
Pablo R. Fillottrani and Guillermo R. Simari.
Weak properties of circumscriptive logic programming.
In Proceedings CACIC'97, 3er. Congreso Argentinio de Ciencias de la Computación., La Plata, Argentina, 1997.

GS98
Alejandro J. García and Guillermo R. Simari.
Defeasible logic programming.
Technical report, Computer Science Department, Universidad Nacional del Sur, October 1998.
Technical Report GIIA-1998-20.

GSC98
Alejandro J. García, Guillermo R. Simari, and Carlos I. Chesñevar.
An argumentative framework for reasoning with inconsistent and incomplete information.
In Workshop on Practical Reasoning and Rationality. 13th biennial European Conference on Artificial Intelligence (ECAI-98), August 1998.

SCG94
G.R. Simari, Chesñevar C.I., and A.J. García.
The role of dialectics in defeasible argumentation.
In XIV Conferencia Internacional de la Sociedad Chilena para Ciencias de la Computación, Universidad de Concepción, Concepción, Chile, 1994.

SL92
G.R Simari and Ronald P. Loui.
A Mathematical Treatment of Defeasible Reasoning and its  Implementation.
Artificial Intelligence, 53:125-157, 1992.