Fully deadline-coupled planning: One step at a time

Abstract

In planning situations involving tight deadlines a commonsense reasoner may spend substantial amount of the available time in reasoning toward and about the (partial) plan. This reasoning involves, but is not limited to, partial plan formulation, making decisions about available and conceivable alternatives, plan sequencing, and also plan failure and revision. The key observation is that the time taken in reasoning about a plan brings the deadline closer. The reasoner should therefore take account of the passage of time during that same reasoning, and this accounting must continuously affect every decision under time-pressure. Step-logics were introduced as a mechanism for reasoning situated in time. We employ them here to create a step-logic planner that lets a time-situated reasoner keep track of an approaching deadline as she/he makes (and enacts) her/his plan, thereby treating all facets of planning (including plan-formation and its simultaneous or subsequent execution) as deadline-coupled.