Explicit Representation of Events, Actions, and Plans for Assumption-Based Plan Reasoning.

摘要

We propose a wide-ranging knowledge representation formalism designed expressly to support many different forms of reasoning about plans. We begin with an event-based language based on the interval temporal logic. The language supports reasoning about action attempts and composite actions, both of which are given axiomatic definitions. We then define a representation for plans viewed as arguments that a certain course of action under certain explicit conditions will achieve certain goals. We can represent both correct and incorrect plans, and reason about why they might or might not fail. An important aspect of this work is the formal characterization of plan reasoning as assumption-based reasoning, to make the non-deductive aspects of plan reasoning explicit. A preliminary implementation of these ideas has already been built as the plan reasoning component of the TRAINS system.