Quasi - Bayesian Strategies for E cient Plan Generation : Applicationto the Planning to

Quasi-Bayesian theory uses convex sets of probability distributions and expected loss to represent preferences about plans. The theory focuses on decision robustness, i.e., the extent to which plans are aaected by deviations in subjective assessments of probability. Generating a plan means enumerating the actions to be taken and providing information about the robustness of the actions. The present work presents plan generation problems that can be solved faster in the Quasi-Bayesian framework than within usual Bayesian theory. We investigate this on the planning to observe problem, i.e., an agent must decide whether to take new observations or not. The fundamental question is: How, and how much, to search for a \best" plan, based on the precision of probability assessments? Plan generation algorithms are derived in the context of material classiica-tion with an acoustic robotic probe. A package that constructs Quasi-Bayesian plans is available through anonymous ftp.