An improved evolutionary algorithm for the two-stage transportation problem with fixed charge at depots

This paper addresses a two-stage transportation problem with a fixed charge at depots. The goal is to determine the best way of delivering a commodity from a set of plants to a set of customers with known demand using a set of potential depots as intermediate transshipment points, while minimizing the overall costs incurred. These costs refer to fixed costs arising from using the depots and to variable shipping costs. To solve the problem, a hybrid evolutionary algorithm is developed which combines the control by the chromosomes of which depots to open with the use of optimization techniques to associate a feasible solution to each chromosome. The computational results show the efficiency of the algorithm in terms of the quality of the solutions yielded and the computing time.