Decision-Theoretic Approach to Plan Recognition

In this report, first we give a survey of the work in plan recognition field, including the evolution of different approaches, their strength and weaknesses. Then we propose two decision-theoretic approaches to plan recognition problem, which explicitly take outcome utilities into consideration. One is an extension within the probabilistic reasoning framework, by adding utility nodes to belief nets. The other is based on maximizing the estimated expected utility of possible plan. Illustrative examples are given to explain the approaches. Finally, we compare the two approaches presented in the report and summarize the work.