Efficient hierarchical planning, based on a task network, is the topic of this research. Goal and subgoal interactions will be investigated to achieve improved control strategies for planning. For example, it should be possible to improve both the quality of the plan and the efficiency of the planning process by developing a control strategy which selects among alternative task reductions in such a way as to avoid harmful interactions while encouraging helpful interactions. The following specific issues are central to this investigation: (1) how the various properties of interactions can guide the choice among alternative reductions in a task network; (2) how to improve the consistency of task network representations, in particular, how to identify situations where a seemingly unresolvable conflict can be resolved at a lower level in the task network; (3) how to take advantage of the fact that some planning tasks, while not independent in general, become independent once certain other plannng decisions have been made. The investigators anticipate that completion of the above research topics will result in significantly improved planning in a number of environments. To test this idea, they will implement a planning system incorporating the above ideas, and evaluate its performance on a number of domains.
