Towards a Self-Learning Agent: Using Ranking Functions as a Belief Representation in Reinforcement Learning
We propose a combination of belief revision and reinforcement learning which leads to a self-learning agent. The agent shows six qualities we deem necessary for a successful and adaptive learner. This is achieved by representing the agent's belief in two different levels, one numerical and one symbolical. While the former is implemented using basic reinforcement learning techniques, the latter is represented by Spohn's ranking functions. To make these ranking functions fit into a reinforcement learning framework, we studied the revision process and identified key weaknesses of the to-date approach. Despite the fact that the revision was modeled to support frequent updates, we propose and justify an alternative revision which leads to more plausible results. We show in an example application the benefits of the new approach, including faster learning and the extraction of learned rules.
ranking functions reinforcement learning belief revision hybrid learning system