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. The conference was organised by SGAI, the British Computer Society Specialist Group on Artificial Intelligence (previously known as SGES). The papers in this volume present new and innovative developments in the field, divided into sections on Machine Learning, Knowledge Representation and Reasoning, Knowledge Acquisition, Constraint Satisfaction, Scheduling and Natural Language Processing. This year's prize for the best refereed technical paper was won by a paper entitled An Improved Hybrid Genetic Algorithm: New Results for the Quadratic Assignment Problem by A. Misevicius (Department of Practical Informatics, Kaunas University of Technology, Lithuania). SGAI gratefully acknowledges the long-term sponsorship of Hewlett-Packard Laboratories (Bristol) for this prize, which goes back to the 1980s. This is the twentieth volume in the Research and Development series. The Application Stream papers are published as a companion volume under the title Applications and Innovations in Intelligent Systems XI. On behalf of the conference organising committee I should like to thank all those who contributed to the organisation of this year's technical programme, in particular the programme committee members, the referees and our administrator Fiona Hartree and Linsay Turbert."

The papers in this volume are the refereed technical papers presented at ES 2002, the Twenty-second SGAI International Conference on Knowledge Based Systems and Applied Artificial Intelligence, held in Cambridge in December 2002. The papers in this volume present new and innovative developments in the field, divided into sections on Machine Learning, Knowledge Representation and Reasoning, Knowledge Acquisition, Constraint Satisfaction and Scheduling, and Natural Language Processing. This is the nineteenth volume in the Research and Development series. The series is essential reading for those who wish to keep up to date with developments in this important field. The Application Stream papers are published as a companion volume under the title Applications and Innovations in Intelligent Systems X.

Keywords: Artificial Intelligence, Expert Systems, Knowledge-based Systems

Contents: Technical programme chairman's introduction.- Best technical paper.- Session 1a: Machine Learning 1.- Session 1b: Knowledge Representation and Reasoning 1.- Session 2a: Machine Learning 2.- Session 2b: Knowledge Representation and Reasoning 2.-Session 3b: Knowledge representation and Reasoning 3.- Session 4: Constraint satisfaction and Scheduling.- Session 5: Natural Language Processing.

This book constitutes the refereed preceedings of the 6th European Conference on Case-Based Reasoning, ECCBR 2002, held in Aberdeen, Scotland, UK in September 2002The 31 revised full research papers and 14 revised application papers presented togehter with 2 invited contributions were carefully reviewed and selected from numerous submissions. All current issues in case-based reasoning, ranging from foundational and methodological issues to advanced applications in various fields are addressed.

The papers in this volume are the refereed technical papers presented at ES2001, the Twenty-first SGES International Conference on Knowledge Based Systems and Applied Artificial Intelligence, held in Cambridge in December 2001.The papers in this volume present new and innovative developments in the field, divided into sections on Machine Learning, Constraint Satisfaction, Agents, Knowledge Representation and Knowledge Engineering.This is the eighteenth volume in the Research and Development series. The series is essential reading for those who wish to keep up to date with developments in this important field.The Application Stream papers are published as a companion volume under the title "Applications and Innovations in Intelligent Systems IX".

The papers in this volume are the Applications papers presented at ES 2001, the Twenty-first SGES International Conference on Knowledge Based Systems and Applied Artificial Intelligence, held in Cambridge in December 2001.The scope of the Application papers has expanded over recent years to cover not just innovative applications using traditional knowledge based systems, but also to include applications demonstrating the whole range of AI technologies. These papers continue to illustrate the maturity of AI as a commercially viable technology to solve real world problems.This is the eighth volume in the "Applications and Innovations in Intelligent Systems" series. The series serves as a key reference as to how AI technology has enabled organisations to solve complex problems and gain significant business benefits.The Technical Stream papers from ES 2001 are published as a companion volume under the title "Research and Development in Intelligent Systems XVIII".

The papers in this volume are the refereed technical papers presented at ES2000, the Twentieth SGES International Conference on Knowledge Based Systems and Applied Artificial Intelligence, held in Cambridge in December 2000. The papers in this volume present new and innovative developments in the field, divided into sections on learning, case-based reasoning, knowledge representation, knowledge engineering, and belief acquisition and planning. This is the seventeenth volume in the Research and Development series. The series is essential reading for those who wish to keep up to date with developments in this important field. The Application Stream papers are published as a companion volume under the title Applications and Innovations in Intelligent Systems VIII.