Efficiently Dispatching Plans Encoded as Simple Temporal Problems

Abstract

The Simple Temporal Problem (STP) formalism was developed to encode flexible quantitative temporal constraints, and it has been adopted as a commonly used framework for temporal plans. This chapter addresses the question of how to automatically dispatch a plan encoded as an STP, that is, how to determine when to perform its constituent actions so as to ensure that all of its temporal constraints are satisfied. After reviewing the theory of STPs and their use in encoding plans, we present detailed descriptions of the algorithms that have been developed to date in the literature on STP dispatch. We distinguish between off-line and online dispatch, and present both basic algorithms for dispatch and techniques for improving their efficiency in time-critical situations.