Scheduling of loading and unloading operations in a multi stations transshipment terminal with release date and inventory constraints

- We consider a transshipment scheduling problem with identical stations.
- We consider release date and inventory constraints.
- We formulate the problem as a mixed integer linear programming model.
- We developed two constructive heuristic and three metaheuristic algorithms.
- Using computational results, the performance of all developed algorithms is analyzed.

In this paper, we study a transshipment scheduling problem with multiple identical loading/unloading stations and release date and inventory constraints. This problem is similar to the parallel machine scheduling problem where the makespan is to be minimized, which is an NP-hard problem in the scheduling theory. We formulate the problem as an integer linear programming model, which is solvable only for small-size instances by CPLEX solver in reasonable times. Also, we develop two constructive heuristic solution approaches, namely parallel and serial schedule generation schemes. We also develop three metaheuristic methods based on genetic algorithm, particle swarm optimization and cuckoo optimization algorithm. The developed solution methods have been compared using computational studies based upon 870 randomly generated test instances. The experimental results show that the parallel schedule generation scheme outperforms the serial one and the cuckoo optimization algorithm shows the best performance among the developed metaheuristic methods.