GeNCA : un modèle général de négociation de contrats entre agents. (GeNCA: a general contract-based negotiation between agents model)
چکیده
When numerous agents interact, conflicts may arise. To solve them, different ways can be used such as cooperation, voting systems or negotiation. The one which interests us in this thesis is contract-based negotiation over resources. The aim of our work is to conceive a general negotiation model (called GeNCA : Generic Negotiation of Contracts API), and to give an implementation of it. This allows a user wishing to develop a negotiation application not to have to do the whole job but to have a model that will facilitate his work. In order to conceive such a model, we begin by studying the different types of negotiation most used. The analysis of these negotiations leads to the collect of their common points, and provides us a basis to conceive our model. Thanks to the collect of these common points and the study of the progress of these negotiations, we show that it is possible to conceive a general negotiation protocol, parameterable, which offer the possibility to make counter-proposals and which can describe the progress of a particular negotiation. We propose a general negotiation model using this protocol and having a management of negotiations mechanism, which allows to negotiate contracts on disjoint sets of resources in parallel, and to negotiate contracts having conflicts on resources sequentially. This model also allows to automatically renegotiate contracts that cannot be met any longer. Our proposition is based on a three-level architecture, that separates the communication part between agents, the negotiation part and the negotiation strategy part of an application. As a matter of fact, the way agents communicate doesn’t play a role in the way negotiation is made, and different communication ways can be used in a same application executed on different environments. We equally show that it is important to separate the negotiation strategy from the two other levels, to allow a user to choose which negotiation strategy he will use without disturbing the remaining of the application. Moreover, the negotiation strategy is intrinsically linked to the negotiation application, and it is obvious that negotiating a ton of potatoes is not the same as negotiating a slot-time for an appointment, nor the same as negotiating the exclusive use of a shared resource for an hour. Our model has been implemented by a Java API also called GeNCA. In order to validate our model, we used our API to achieve different applications such as an auction system, an appointment taking system and a system to negotiate the choice of a restaurant for a common trip.