Hierarchical heuristic forward search in stochastic domains Conference Paper uri icon


  • Abstract Many MDPs exhibit an hierarchical structure where the agent needs to perform various subtasks that are coupled only by a small sub-set of variables containing, notably, shared resources. Previous work has shown how this hierarchical structure can be exploited by solving several sub-MDPs representing the different subtasks in different calling contexts, and a root MDP responsible for sequencing and synchronizing the subtasks, instead of a huge MDP representing the whole problem. Another important idea used by efficient algorithms for solving flat MDPs, such as (L) AO* and (L) RTDP, is to exploit reachability information and an admissible heuristics in order to accelerate the search by pruning states that cannot be reached from a given starting state under an optimal policy. In this paper, we combine both ideas and develop a variant of the AO* algorithm for performing forward …

publication date

  • January 1, 2007