Crane scheduling using tabu search

We examine crane scheduling for ports. This important component of port operations management is studied when certain spatial constraints, which are common to crane operations, are considered. Although there has been some work on crane scheduling, such spatial constraints have not been previously developed. We assume that ships can be divided into holds and that cranes can move from hold to hold but that only one crane can work on one hold or job at any one time. The objective is to find a crane-to-job matching which will maximize throughput for such operations under these basic spatial constraints. We propose two dynamic programming algorithms, prove NP-completeness of the problem and provide heuristics to solve the crane scheduling problem with spatial constraints. We develop probabilistic tabu search techniques for application to the problem which are easy to implement. In experiments, we compare the performance of tabu search with other algorithms applied to the crane scheduling problem.