A solution approach for a dock-door assignment problem

One of the most important performance criteria in door assignment problems in cross docking is unloading and loading times. In the literature related to the door assignment problem in the cross docking, it is assumed that these times are known in advance. However, depending on the number of workers assigned to the doors, the unloading and loading times also vary. Therefore, in this study, the problem of assigning trucks to doors in cross-docking is handled together with the problem of determining how many workers will be assigned to each door. A mixed integer linear mathematical model has been developed for the problem in question. The proposed model was compared with two different scenarios (ÇSKA-S1 and ÇSKA-S2) where a fixed number of workers were assigned to the doors. The performance of the model is demonstrated by using the test problems taken from the literature. The results revealed that assigning the appropriate number of workers to the doors can improve the value of the objective function by an average of 3.14% for Scenario-1 and 4.02% for Scenario-2, compared to scenarios where the number of workers is assumed constant. In addition, in order to examine the effect of the total number of workers on the objective function, test problems of different sizes were solved with different numbers of workers and the contribution of increasing the number of workers was analyzed. The contribution graphs drawn provide important information to the decision maker in determining the total number of workers.