The SINIX Consultant – Towards a Theoretical Treatment of Plan Recognition

摘要

We have realized the help system SINIX Consultant (SC) for SINIX1 users. The system is capable of answering – in German – natural language questions concerning SINIX commands, objects, and concepts. But not only does this help system react to inquiries – additionally, the system is capable of activating itself. If the user employs a sequence of SINIX commands (a plan) in order to reach a specific goal, the help system proposes a sequence which reaches the same goal, but, with fewer commands. In this paper, a brief survey of the SINIX Consultant and the realized plan recognizer REPLIX is first given. Then, an initial attempt of a theoretical treatment of plan recognition is presented. This is done within the logical framework. We show how we can use an interval-based logic of time to describe actions, atomic plans, non-atomic plans, action execution, and simple plan recognition. We also show that the recognition of inserted sub-plans managed by REPLIX can be handled as well. Then, we present a problem which cannot be treated in the formalism. Thus, in this paper, we don't present a full developed theory but nevertheless, a step towards it.