Stable Solutions Dealing with Dynamics in Scheduling Based on Dynamic Constraint Satisfaction Problems

Abstract

The real-life scheduling problems are often over-constrained, and there is often one intractable case where unexpected events are added and a sudden change is required. In this paper, we describe such problems as the Dynamic Valued Constraint Satisfaction Problem (DyVCSP). In DyVCSP, although the previous schedule would be modified when there is some change, the new schedule should be similar to the current one. We propose a method for achieving solution stability, which maintains portions of the current schedule using the provisional soft constraint. The provisional constraint ensures each variable keeps its value as much as possible. In this paper, we formalize the nurse scheduling problem as DyVCSP and use our method to achieve solution stability.