The solution of the concurrent layout scheduling problem in the job-shop environment through a local neighborhood search algorithm

The concurrent layout and scheduling problem is an extension of the well-known job-shop scheduling problem with transport delays, in which, in addition to the decisions taken in the classic problem, the location of machines must be selected from a set of possible sites. The aim of this study was to solve this problem by using a local neighborhood search algorithm (LNSA). This algorithm used a random local neighborhood, where neighbors were produced by simple operators commonly used in metaheuristics for scheduling problems. The solution coding used in the LNSA enabled all the calculated solutions to be valid schedules for the problem. The findings of the study were compared with those obtained by Ranjbar, who proposed the benchmark problems. Our method obtained a minor average relative percentage compared to the best-known results. Furthermore, it achieved a smaller makespan in the problems with higher computational complexity, which may aid companies that require customized manufacturing. (C) 2019 Elsevier Ltd. All rights reserved.