Flexible Plan Verification: Feasibility Results

Abstract

Timeline-based planning techniques have demonstrated wide application possibilities in heterogeneous real world domains. For a wider diffusion of this technology, a more thorough investigation of the connections with formal methods is needed. This paper is part of a research program aimed at studying the interconnections between timeline-based planning and standard techniques for formal validation and verification (V&V). In this line, an open issue consists of studying the link between plan generation and plan execution from the particular perspective of verifying temporal plans before their actual execution. The present work addresses the problem of verifying flexible temporal plans, i.e., those plans usually produced by least-commitment temporal planners. Such plans only impose minimal temporal constraints among the planned activities, hence are able to adapt to on-line environmental changes by trading some of the retained flexibility. This work shows how a model-checking verification tool based on Timed Game Automata (TGA) can be used to verify such plans. In particular, flexible plan verification is cast as a model-checking problem on those automata. The effectiveness of the proposed approach is shown by presenting a detailed experimental analysis with a real world domain which is used as a flexible benchmark.