Role Delegation and Dynamic Architectures in Conversational Multi-Agent Systems

i Preface efore starting the actual thesis dissertation, I would like to give to the reader some information about the context in which this research work took place. This research has been done in the CEXAS team of the LIRIS laboratory (formerly in the LISI laboratory), in the university of Lyon I. B It has been started in November 1999 under the supervision of pr. Jean-Marc Fouet, and later on, after Jean-Marc passed away, under the supervision of Salima Hassas, and the co-supervision of pr. Alain Mille. During the first year, I have also been supervised by pr. Kwang-Young Lee, from the AI laboratory of KAIST (Korean Institute of Science and Technology), in Taejon, South Korea. Initially, this PhD was to be done in co-supervision between these two universities (in France we call such co-supervised PhD " cotutelle "). Unfortunately for administrative reasons, this collaboration has been turned into a simple exchange year in KAIST, which has not prevented me from taking a great benefit, scientifically as well as personally, from this wonderful experience. After my return in June 2000, I spent my second PhD year in Lyon I. But I had to go to national service after that, in November 2001, interrupting the PhD for 18 months, in Laos and Vietnam. This long interruption had some consequences on my research, that I had to update after my return in May 2002 because of the rapid evolution of MAS even in such a 18 months period. Overall, these two environment changes and this interruption have been both a difficulty and a source of inspiration, and somehow contributed to the fact that the research is divided into three quite distinct parts, even though these three parts are the logical continuity of each other. Acknowledgments would like to especially thank Salima Hassas, whose confidence in my work and diligence have made this thesis possible. I am also grateful to Alain Mille which has been able to take over, after my former adviser pr. Jean-Marc Fouet passed away, despite the great diversity of research directions in our team.