Publisher's Synopsis
The "tradeoff formulation" task is to identify the central issues in a decision problem by recognizing strategies that are qualitatively inadmissible. SUDO-PLANNER formulates tradeoffs for an example medical decision problem by proving decision-theoretically that certain classes of plans are dominated based on qualitative relations in the domain.;The inadequancy of the traditional predicate representation of goals for choice among plans that may achieve objectives in part or with uncertainty motivates SUDO-PLANNER's "dominance-proving architecture", a general framework for planning for partially satisfiable goals. Dominance-proving planners delimit the space of admissible plans by maintaining a specialization graph of plan classses annotated with dominance conditions derived from a domain model.;"Qualitative probabilistic networks" (QPNs) are decision models expressing constraints on the joint probability distribution over a set of variables. "Qualitative influences" describe the direction of the relationship between two variables. "Qualitative synergies" describe interactions among influences. The probabilistic definitions of these constraints justify sound and efficient inference procedures based on graphical manipulations of the network.;SUDO-PLANNER's dominance prover uses these procedures to establish dominance relations among plan classes. SUDO-PLANNER constructs decision models (QPNs) from a knowlege base describing the effects of actions and relations among events at multiple levels of abstraction. The planning process alternates between model construction and dominance proving, producing a plan graph with dominance conditions ruling out the inadmissible therapy strategies for its medical decision example.
