Incrementally Solving STNs by Enforcing Partial Path Consistency

Efficient management and propagation of temporal constraints is important for temporal planning as well as for scheduling. During plan development, new events and temporal constraints are added and existing constraints may be tightened; the consistency of the whole temporal network is frequently checked; and results of constraint propagation guide further search. Recent work shows that enforcing partial path consistency provides an efficient means of propagating temporal information for the popular Simple Temporal Network (STN). We show that partial path consistency can be enforced incrementally, thus exploiting the similarities of the constraint network between subsequent edge tightenings. We prove that the worst-case time complexity of our algorithm can be bounded both by the number of edges in the chordal graph (which is better than the previous bound of the number of vertices squared), and by the degree of the chordal graph times the number of vertices incident on updated edges. W...

• Type: Conference
• Year: 2010
• Where: AIPS
• Authors: Léon Planken, Mathijs de Weerdt, Neil Yorke-Smith
• Keywords: AIPS 2010, Artificial Intelligence, Partial Path Consistency, Temporal Constraints, Temporal Network