A Time and Resource Problem in Planning Architectures

Abstract. This paper concerns the problem of resource reasoning in planning. It defines formally a constraint satisfaction problem, the Time and Resource Problem (T RP), in which resource reasoning is seen as integrated with temporal reasoning. Two propagation techniques are in-troduced that reason about resource constraints in the T RP framework. The Profile Propagation technique, similar to time-tabling techniques, considers resource utilization in single instants of time (the time values) to synthesize necessary quantitative temporal constraints. The Order Propagation technique is more original. It observes single time points (the time variables) and their orderings to synthesize necessary qualita-tive temporal constraints.