Under-Approximating Expected Total Rewards in POMDPs
- URL: http://arxiv.org/abs/2201.08772v1
- Date: Fri, 21 Jan 2022 16:43:03 GMT
- Title: Under-Approximating Expected Total Rewards in POMDPs
- Authors: Alexander Bork, Joost-Pieter Katoen, Tim Quatmann
- Abstract summary: We consider the optimal expected total reward to reach a goal state in a partially observable Markov decision process (POMDP)
We use mixed-integer linear programming (MILP) to find such minimal probability shifts and experimentally show that our techniques scale quite well.
- Score: 68.8204255655161
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: We consider the problem: is the optimal expected total reward to reach a goal
state in a partially observable Markov decision process (POMDP) below a given
threshold? We tackle this -- generally undecidable -- problem by computing
under-approximations on these total expected rewards. This is done by
abstracting finite unfoldings of the infinite belief MDP of the POMDP. The key
issue is to find a suitable under-approximation of the value function. We
provide two techniques: a simple (cut-off) technique that uses a good policy on
the POMDP, and a more advanced technique (belief clipping) that uses minimal
shifts of probabilities between beliefs. We use mixed-integer linear
programming (MILP) to find such minimal probability shifts and experimentally
show that our techniques scale quite well while providing tight lower bounds on
the expected total reward.
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