Progress in Artificial Intelligence

The Portuguese Association for Arti cial Intelligence (APPIA) has been re- larly organising the Portuguese Conference on Arti cial Intelligence (EPIA). This ninth conference follows previous ones held in Porto (1985), Lisboa (1986), Braga (1987), Lisboa (1989), Albufeira (1991), Porto (1993), Funchal (1995) and Coimbra (1997). Starting in 1989, the conferences have been held biennially (alternating with an APPIA Advanced School on Arti cial Intelligence) and become truly international: English has been adopted as the o cial language and the proceedings are published in Springer's LNAI series. The conference has recon rmed its high international standard this year, largely due to its programme committee, composed of distinguished researchers in a variety of specialities in Arti cial Intelligence, half of them from Portuguese universities. This has attracted a signi cant international interest, well expressed by the number of papers submitted (66), from 17 di erent countries, 29 of which are by Portuguese researchers. From the 66 papers submitted, about one third of them (23) were selected for oral presentation and have been published in this volume. The review process enabled the selection of high quality papers, each paper being reviewed by two or three reviewers, either from the programme committee or by their appointment. We would like to thank all of the reviewers for their excellent and hard work.

Inhalt
Invited Lectures.- Combinatorial Optimization in OPL Studio.- Challenges for Inductive Logic Programming.- Holonic Multiagent Systems Theory and Applications .- Constraint Programming.- On the Accuracy and Running Time of GSAT.- The Impact of Branching Heuristics in Propositional Satisfiability Algorithms.- A Tractable Subclass of the Block Algebra: Constraint Propagation and Preconvex Relations.- Is a Tractable Language?.- Natural Language Processing.- Inclusion of Picture Sequences in Generated Documents.- Using LocalMaxs Algorithm for the Extraction of Contiguous and Non-contiguous Multiword Lexical Units.- On the Formal Distinction between Literal and Figurative Language.- Spatial Reasoning.- Qualitative Theory of Shape and Structure.- Logic Programming.- A New Formulation of Tabled Resolution with Delay.- YapOr: An Or-Parallel Prolog System Based on Environment Copying.- Theorem Proving.- Structure Theorems for Closed Sets of Implicates/Implicants in Temporal Logic.- Critical Agents Supporting Interactive Theorem Proving.- Reasoning Under Uncertainty.- A Practical Approach to Fusing Prioritized Knowledge Bases.- Fuzzy Behaviors and Behavior Arbitration in Autonomous Vehicles.- Multi-agent Systems.- A Multi-agent System for Electronic Commerce Including Adaptive Strategic Behaviours.- Choice and Institutions in Agent Societies.- Analytic Modal Revision for Multi-agent Systems.- Decisions Based upon Multiple Values: The BVG Agent Architecture.- Abduction and Revision.- Temporal Abductive Diagnosis.- A New Approach to Base Revision.- Improving Optical Music Recognition by Means of Abductive Constraint Logic Programming.- Genetic Algorithms.- Genetic Algorithms for Solving Open Shop Scheduling Problems.- Expressing Population Based Optimization HeuristicsUsing PLATO.