An Application of Global Abduction to an Information Agent Which Modifies a Plan Upon Failure - Preliminary Report

This paper proposes an implementation of an information agent in a new form of abductive logic programming called global abduction [11]. We consider an information agent which performs not only information gathering, but also actions which update the outside world. However, since the success of the actions is not guaranteed, the agent might encounter a failure of some action. In this case, the agent needs to modify an alternative plan with consideration to the side-effects caused by the already-executed actions. In this paper, we solve the problem of such plan modification by using global abduction. Global abduction is a new form of abduction whose abducibles can be referred to in any search path once abduced. This mechanism is used to propagate information about already-executed actions so that we can modify an alternative plan to accommodate side-effects caused by the already-executed actions.