This is an ROW/Planning Grant. In many problem areas, such as robotics, planning must occur in a dynamic and unpredictable environment. As in any reasoning process, the act of planning takes time to complete - the more time that is spent in planning, the less time that is available to enact the final solution. Thus when planning in a real-time environment we must consider the time required not only to enact the plan, but also to form the plan. A real-time planning system then must be able to recognize the fact that its reasoning takes time, and the during this time, changes in the world can occur (which may affect its reasoning). Most of the work that has been done in formalizing commonsense reasoning and in planning has left this issue unaddressed. The objective of this research is to understand the role that time plays in planning and to design a formal model of planning that incorporates time. We propose to extend step- logic to address these real-time planning issues. Step-logic is a formal mechanism for modeling the ongoing process of reasoning. Unlike traditional logical formalism, step-logic does not calculate a final set of conclusions which can be drawn from an initial set of facts, but rather monitors the ever-changing set of conclusions as time goes on.//
