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RAPID: A Reachable Anytime Planner for Imprecisely-sensed Domains
Proceedings of the 26th Conference on Uncertainty in Artificial Intelligence, PMLR R8:91-100, 2010.
Abstract
Despite the intractability of generic optimal par- tially observable Markov decision process plan- ning, there exist important problems that have highly structured models. Previous researchers have used this insight to construct more effi- cient algorithms for factored domains, and for domains with topological structure in the flat state dynamics model. In our work, motivated by findings from the education community rele- vant to automated tutoring, we consider problems that exhibit a form of topological structure in the factored dynamics model. Our Reachable Any- time Planner for Imprecisely-sensed Domains (RAPID) leverages this structure to efficiently compute a good initial envelope of reachable states under the optimal MDP policy in time lin- ear in the number of state variables. RAPID per- forms partially-observable planning over the lim- ited envelope of states, and slowly expands the state space considered as time allows. RAPID performs well on a large tutoring-inspired prob- lem simulation with 122 state variables, corre- sponding to a flat state space of over 1030 states.