Hierarchical POMDP Controller Optimization by Likelihood Maximization
Marc Toussaint, Laurent Charlin, Pascal Poupart
Planning can often be simpli ed by decomposing the task into smaller tasks arranged hierarchically. Charlin et al.  recently showed that the hierarchy discovery problem can be framed as a non-convex optimization problem. However, the inherent computational di culty of solving such an optimization problem makes it hard to scale to realworld problems. In another line of research, Toussaint et al.  developed a method to solve planning problems by maximumlikelihood estimation. In this paper, we show how the hierarchy discovery problem in partially observable domains can be tackled using a similar maximum likelihood approach. Our technique rst transforms the problem into a dynamic Bayesian network through which a hierarchical structure can naturally be discovered while optimizing the policy. Experimental results demonstrate that this approach scales better than previous techniques based on non-convex optimization.
PDF Link: /papers/08/p562-toussaint.pdf
AUTHOR = "Marc Toussaint
and Laurent Charlin and Pascal Poupart",
TITLE = "Hierarchical POMDP Controller Optimization by Likelihood Maximization",
BOOKTITLE = "Proceedings of the Twenty-Fourth Conference Annual Conference on Uncertainty in Artificial Intelligence (UAI-08)",
PUBLISHER = "AUAI Press",
ADDRESS = "Corvallis, Oregon",
YEAR = "2008",
PAGES = "562--570"