Multi-player multi-issue negotiation with incomplete information in agent-based activity-travel scheduling

Joint activities have been investigated mostly in the context of household-based models of travel demand. The joint decision concerns different issues that require agreement. In the context of household decision making, it can be assumed that the utility functions of members are known. In other than household contexts, however, because of various backgrounds among participants, one participant may not want to disclose his utility function to others except for his proposal. Moreover, it may be difficult to find a participant who can evaluate various proposals from all the participants including his own and make a fair decision for all. Therefore, each participant on the one hand tries to cooperate with others so as to reach an agreement on the joint activity, and on the other hand tries to compete with others in order to maximize his own benefits. Given such a semi-cooperative environment, the methods used in the joint activity scheduling area cannot be directly extended to the semicooperative environment. Negotiation is a suitable approach to lead the way on how to reach an agreement on multiple issues and decide on a joint activity. We propose a multi-player multi-issue multilateral negotiation model by which agents submit proposals sequentially in consecutive rounds until some deadline. The proposed negotiation model can assist the activity travel scheduling process. We develop negotiation strategies of the agents under an incomplete information setting. For each pair of the specific values of the discrete issues, the strategies are composed of an agreement-search method and concession strategies in the continuous issues’ space. Finally, a preliminary example is provided to show how three agents focusing on four issues will come to a solution on those issues in the base level negotiation model.