Laura L. Pullum, Oak Ridge National Laboratory, USA

Reinforcement learning (RL) has received significant interest in recent years, primarily because of the success of deep RL in solving many challenging tasks, such as playing chess, Go, and online computer games. However, with the increasing focus on RL, applications outside gaming and simulated environments require an understanding of the robustness, stability, and resilience of RL methods. To this end, we conducted a comprehensive literature review to characterize the available literature on these three behaviors as they pertain to RL. We classified the quantitative and theoretical approaches used to indicate or measure robustness, stability, and resilience behaviors. In addition, we identified the actions or events to which the quantitative approaches attempted to be stable, robust, or resilient. Finally, we provide a decision tree that is useful for selecting metrics to quantify behavior. We believe that this is the first comprehensive review of stability, robustness, and resilience, specifically geared toward RL.

Reinforcement Learning, Resilience, Robustness, Stability.