Job-shop scheduling with mixed blocking constraints between operations

Abstract

Job-shop scheduling problem is a very hard issue in operations research and is studied since a long time, with a wide variety of constraints. This paper addresses the job-shop scheduling problem with a new kind of constraint. The particular issue we have been interested in is about mixed blocking constraints from an operation to its successor in job tasks list. In this paper, a mathematic model is proposed and its results in Mosel Xpress software presented. Then, an evaluation function is proposed and tested with a genetic algorithm on this problem. Results are given and compared to optimal results obtained with the mathematic model on four benchmarks, each composed of twenty instances.