Dealing with ambiguity in plan recognition under time constraints

Plan recognition has been widely used in agents that need to infer which plans are being executed or which activities are being performed by others. In many applications, reasoning and acting in response to plan recognition requires time. In such systems, plan recognition is expected to be made not only with precision, but also in a timely fashion. When recognition cannot be made in time, an agent attempting to recognize plans can interact with the observed agents to disambiguate multiple hypotheses. However, such an intrusive behavior is often not possible, very costly, or undesirable. In this paper, we focus on the problem of deciding when to interact with the observed agents in order to determine their plans under execution. To tackle this problem, we develop a plan recognizer that, on one hand is the least intrusive possible, and on the other hand attempts to recognize the plans of the observed agents with precision as soon as possible and no later than it is viable to respond to the recognized plan.