Frans Coenen University of Liverpool, UK This volume comprises the refereed technical papers presented at AI2003, the Twenty­ third SGAI International Conference on the theory, practice and application of Artificial Intelligence, held in Cambridge in December 2003.

Best Refereed Technical Paper.- An Improved Hybrid Genetic Algorithm: New Results for the Quadratic Assignment Problem.- Session 1A: Algorithms And A1 (Gas, Hidden Markov Models, Simulated Annealing And Perceptrons.- Adaptive Mutation Using Statistics Mechanism for Genetic Algorithms.- Off-line Recognition of Handwritten Arabic Words Using Multiple Hidden Markov Models.- On a New Stepwidth Adaptation Scheme for Simulated Annealing and its Practical Application.- An Approximate Algorithm for Reverse Engineering of Multi-layer Perceptrons.- Session 18: Constraint Programming I.- A Theoretical Framework for Tradeoff Generation using Soft Constraints.- Maximum Partial Assignments for Over-Constrained Problems.- Escaping Local Optima in Multi-Agent Oriented Constraint Satisfaction.- Constraint Acquisition as Semi-Automatic Modeling.- Session 2A: Knowledge Discovery In Data (Association Rules, Clustering And Classification).- Strategies for Partitioning Data in Association Rule Mining.- A Self-Organising Hybrid Model for Dynamic Text Clustering.- Polynomial-Fuzzy Decision Tree Structures for Classifying Medical Data.- A Comparison of Generic Machine Learning Algorithms for Image Classification.- Session 2B: Constraint Programming 2.- Turtle: A Constraint Imperative Programming Language.- Symmetry Breaking in Soft CSPs.- How to Classify Hard and Soft Constraints in Non-binary Constraint Satisfaction Problems.- Lightweight MAC Algorithms.- Session 3: Spatio-Temporal Reasoning And Machine Learning.- SPARQS: Automatic Reasoning in Qualitative Space.- Incorporating Reactive Learning Behaviour into a Mini-robot Platform.- An Approach to Instance Reduction in Supervised Learning.- Session 4: Knowledge Organisation, Representation, V&V and Refinement.- Optimal Decision Explanation byExtracting Regularity Patterns.- Model-based Planning in Physical domains using SetGraphs.- Quality Checking of Medical Guidelines through Logical Abduction.- Constraint Relaxation Techniques to Aid the Reuse of Knowledge Bases and Problem Solvers.- Session 5: Multi-Agent Systems And Recommender Systems.- Adaptive Brokering in Agent-Mediated Electronic Commerce.- CONOISE: Agent-Based Formation of Virtual Organisations.- I-SPY — Anonymous, Community-Based Personalization by Collaborative Meta-Search.- Balancing User Satisfaction and Cognitive Load in Coverage-Optimised Retrieval.