I am or was involved in the following events:

• 1st International Workshop on Computational Social Choice Amsterdam, 6-8 December 2006. Program Committee.
• European Agent Systems Summer School (EASSS)
  1999, Utrecht, the Netherlands: local organiser
  2000, Saarbrucken: member of the EASSS board
  2001, Prague: Co-chair
  2002, Bologna: Chair
  2003, Barcelona: Chair
  2004, Liverpool: Chair
  2005, Utrecht, the Netherlands: Chair.


• JELIA'06, the European Conference on Logics in AI, Liverpool, UK, 2006. Conference Chair.


• IFIP International Conferences on Artificial Intelligence Applications and Innovations, Santiago, Chile, August 2006. Program Committee.


• The First International Conference on Knowledge Science, Engineering and Management (KSEM'2006), China, 2006. Program Committee.


• Belief Change, a workshop in conjunction with the International Workshop on Nonmonotonic Reasoning (NMR-06). Program Committee.


• German Conference on Multiagent Systems Technologies (MATES 2005), September 12 - 14, Koblenz, Germany
  Program Committee.
  2006, September 18 - 21, Program Committee
  

• Game Theoretic and Decision Theoretic Agents, Hakodate, Japan, May 2006. Program Committee member.
• International Association for Development of the Information Society (IADIS) organised Intelligent Systems and Agents (ISA2005)} Conference.
  2005, 11 - 29 April, virtual conference, member of the Scientific Committee.

• Workshop Belief Revision and Dynamic Logic. 15 - 19 August, 2005, Edinburgh, Scotland.
  Program Committee.
  

• European Workshop on Multi-Agent Systems
  2003, Oxford, UK, program committee.
  2004, Barcelona, Spain, PC Chair

• The IEEE/WIC/ACM International Joint Conference on Web Intelligence and Intelligent Agent Technology (WI/IAT)
  September 19-22, 2005, Compiègne, program committee
  December 18 - 22, 2006, Hong Kong, program committee.


• European School on Logic, Language and Information (ESSLLI), Edingurgh, Scotland, August 2005; program committee member for the Logic and Computation Section.

• European Conference on Logics in Artificial Intelligence (Jelia), Lisbon, Portugal, 27 - 30 September 2004.

• Workshop Logic and Multiagent Systems (LAMAS).
  Auckland, New Zealand, 9 and 10 August, 2004; program committee.
• The Nineteenth National Conference on Artificial Intelligence (AAAI)
  2004, San Jose, California, program committee.

• IEEE/WIC/ACM International Conference on Intelligent Agent Technology (IAT 2004), September 21-24 2004, Beijing, China, program committee.

• European Workshop on Multi-Agent Systems
  2003, Oxford, UK, program committee.

• Logic and the Foundations of Game and Decision Theory (LOFT)
  • 2006, Liverpool, UK: co-chair.
  • 2004, Leipzig, Germany: co-chair.
  • 2002, Turin, Italy: co-chair.
  • 2000, Turin, Italy: co-chair.
  • 1998, Turin, Italy: progam committee.
  • 1996, Mareseille, France: program committee.

• Logic and Communication in Multi-Agent Systems, sattelite event of ICALP 2003.
  2003: Eindhoven, The Netherlands, co-chair.

• Multi-Agent Systems and Artificial Intelligence for the Internet, satelite event of the Portugese Conference on Artificial Intelligence.
  2003, Beja, Portugal: program committee.

• Formal Approaches to Multi-Agent Systems (FAMAS),
  2003, Warsaw, Poland: program committee member.
  2005, Riva del Garda, Italy: program committee member.

• Declarative Agent Languages and Technologies (DALT), workshop at AAMAS.
  2003: Melbourne, Australia: program committee member.
  2004: New York, USA: program committee member.
  

• Workshop of the UK SPECIAL INTEREST GROUP ON MULTIAGENT SYSTEMS (UKMAS).
  2002, Liverpool: program committee member.
  

• The first day on AI and education for Belgium and the Netherlands (BNAIS).
  2002, Utrecht: senior coach of the organising students.

• Computational Logic in Multi-Agent Systems (CLIMA).
  2002, Copenhagen: program committee member.
  January 2004, Florida: program committee member.
  September 2004, Lisbon, Portugal: program committee member.
  June 2005, London, UK. May 2006, Japan: program committee member.

• Conference on Autonomous Agents and Multi-Agent Systems (AAMAS),
  2002, Bologna, Italy: program committee member.
  2003, Melbourne, Australia: senior program committee member.
  2004, New York, USA: senior program committee member
  2005, Utrecht, The Netherlands: program committee member

• Workshop on Agent Communication Languages and Conversation Policies.
  2002, co-located at AAMAS, Bologna, Italy: program committee member.
  

• Workshop on Logics for Agent Based Systems, satellite activity of Eighth International Conference on Principles of Knowledge Representation and Reasoning (KR2002)
  2002: program committee member.

• The International Symposium From Agent Theory to Agent Implementation (AT2AI)
  2002, Vienna: program committee member.
  2004, Vienna: program committee member.
  

• The First International Joint Conference on Autonomous Agents \& Multi-Agent Systems (AAMAS 2002)
  2002, Bologna: program committee member
  2003, Melbourne: senior program committee member.
  2004, New York: senior program committee member.

• Towards a Logic for Rational Agency
  2001: co-proposer and organiser (with M. Wooldridge) of this workshop: granted by the `Internationales Begegnungs- und Forschungszentrum f\"ur Informatik', to be held in Dagstuhl, January 2002.

• Logic, Game Theory and Social Choice (LGCS)
  2001: co-organisor (with M. Kaneko) of the logic section.

• International Workshop of Central and Eastern Europe on Multi-Agent Systems (CEEMAS)
  2001: program committee member.
  2003: program committee member.
  2005: Budapest, Hungary, program committee member.
  2007: Leipzig, Germany, program committee member.

• Formal Aspects of Practical Reasoning (FAPR)
  2000: co-organiser (with John-Jules Meyer) of a complementing workshop on `Practical Reasoning Agents' (London).

• Autonomous Agents
  2000, Barcelona: tutorial chair.

• European Summer School on Logic, Language and Information (ESSLLI)
  
  • 1999: co-organiser (with J.-J.Ch. Meyer and C. Witteveen) of a workshop on Collective Agent Based Systems (Utrecht).
    
  • 1998, 1999: Senior Program Chair of the student session on Logic, Language and Computation.
    
  • 1997: co-organiser (with Yves Lesperance and Richard Scherl) of a workshop on Rational Agency (Aix en Provence).
    

• Genetic and Evolutionary Computation Conference (GECCO)
  1999: program committee member for the special track on `Artificial Life, Adaptive Behaviour and Agents'.

• International Workshop on Agent Theories, Architectures and Languages (ATAL)
  1999, 2000: program committee.

• Dutch-German Workshop on Non-monotonic Reasoning
  1995: local organiser in Utrecht.
  1993, 1995, 1997, 1999, 2001: program committee member.

• Theoretical Aspects of Reasoning About Knowledge (TARK)
  1996: local organiser.
  2000: program committee.

• European RoboCup Championship
  2000: organiser of workshop, program committee member.

• RoboCup
  2000, 2001: program committee member.

• European Agent Systems Summer School (EASSS)
  2002, member of the orngaising board.
  1999, 2000, 2001: invited teacher.
  1999: local organiser.

• (Belgisch)-Nederlands AI Conferentie ((B)NAIC)
  1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004: program committee.
  1996: organising committee.

• Formal Representation and Specification Techniques (FOREST)
  1995 - 1997: organiser of this colloquium.