Scheduling of Trucks at The Cross-Dock By The 4th Party Logistics Service Provider, Taking Into Account Fixed Costs and Waiting Costs

In this paper, the scheduling of inbound and outbound trucks in a cross-dock is investigated. The objective is to minimize the total cost of transportation from the supplier to the         cross-dock, transfer costs from the cross-dock to the retailers, fixed costs for selecting and contracting with the desired fleets, and also the waiting time of the trucks at the cross-dock. Also, the selection of more suitable fleets, as well as the selection and allocation of vehicles for each fleet to transport goods from each supplier, as well as the allocation of the appropriate vehicle to transport goods for each retail store, are calculated according to heterogeneous vehicles and the various orders of each retailer. Also, the appropriate allocation of trucks to the doors, the sequence of trucks in the queue, and the arrival time and departure time of the vehicles are calculated. A MIP model is formulated. Since this model is NP-Hard, the meta-heuristic method of the genetic algorithm is also presented to solve larger problems. Then, to confirm the effectiveness, several examples are examined and the results obtained from solving the mathematical model, and the meta-heuristic solution are compared. In the end, a detailed sensitivity analysis has been performed on the outputs, which shows that the proposed method is fully approved and works very close to the exact method in small dimensions, with the difference that it has the ability to solve larger problems as well.