A Nurse Scheduling System Based on Dynamic Constraint Satisfaction Problem

摘要

In this paper, we describe a new nurse scheduling system based on the framework of Constraint Satisfaction Problem (CSP). In the system, we must deal with dynamic changes to scheduling problem and with constraints that have different levels of importance. We describe the dynamic scheduling problem as a Dynamic Weighted Maximal CSP (DW-MaxCSP) in which constraints can be changed dynamically. It is usually undesirable to drastically modify the previous schedule in the re-scheduling process. A new schedule should be as close to as possible to the previous one. To obtain stable solutions, we propose methodology for keeping similarity to the previous schedule by using provisional constraints that explicitly penalize changes from the previous schedule. We have confirmed the efficacy of our system experimentally.