Solving Nurse Scheduling Problem by Integer-Programming-Based Local Search

The nurse scheduling problem is known as a hard combinatorial problem that has complex constraints. In this paper, we introduce a hybrid algorithm using integer programming and local search, applicable to work tables with periods of 4 weeks or longer. This algorithm updates shifts within an allocation window of a few days width, and this operation is repeated for the entire scheduling period. The update operation is formulated as an integer programming model. Results from simulations on benchmark problem sets for a typical hospital in Japan shows that this algorithm facilitated in creating schedules in a short time with constraints substantially satisfied.