A model of flexible exception handing facilitated by polices and contracts

Due to the dynamic nature of virtual organization (VO), it is necessary that multi-agent system aimed to form and operate VO should be robust in cooperating process. We present a model of flexible exception handling facilitated by polices and contracts, in which the flexible evolvement process of exception handling is divided into three phases: exception analysis, plan generation, and plan deployment. On the one hand, contract signed by cooperative partners describes the cooperation process of the partners, and on the other hand, policies can be used to describe the way to handle exception happened during cooperating process. The three phrases and the import of polices makes the exception handling process more flexible, thus makes the MAS more robust.