Logistics Scheduling And Stowage Planning In Logistics Operation Management

Along with the vigorous development of logistics, it becomes an effective mean by improving the logistics operation management level to reduce the logistics cost and increase the enterprise competitiveness. In this dissertation, the product stowage planning problem of ship and train transportation, the truck and trailer scheduling problem are addressed by modeling and optimizing with taking the iron and steel industry logistics of manufacturing system as the first background, and the relevant stowage decision support system is designed and developed for ship and train transportation. The system has been put into practical use in certain domestic steel plant. The container stowage planning problem and the integrated scheduling problem with truck scheduling and storage allocation are studied with taking the container terminal logistics operation of logistics system as the second background. The main contents include:1) The container stowage planning problem is researched and it considers the task of loading containers into the containership with a set of structural and operational restrictions. It is formulated as an integer programming model to minimize the number of shift, the total loading time and the weight difference between maximum loaded bay and minimum loaded bay. For solving this problem, the tabu search algorithm with two stages search including the intensification search and diversification search is proposed, and the speedup strategy based on computing the improvement of objective function is also designed. The experimental results that compare with optimal solution or lower bound calculating by CPLEX show that the average gap value of TS is1.95%.2) The integrated problem with truck scheduling and storage allocation is researched in the dissertation. In the integrated problem, container’s arrival is dynamic, truck can be used circularly, stacking position of containers and truck scheduling need to be decided. It is formulated as an integer programming model to minimize makespan of the whole discharging course and the truck scheduling constraints and operation constraints of stack crane are also considered. For solving this problem, two stages tabu search algorithm is designed and two kinds of speedup strategy are used in the algorithm. The experimental results comparing with software CPLEX11.0show that the two stage tabu search obtains optimal solution for seven cases of total cases and the average gap of left cases is less than5%, which indicates that this algorithm can solve this integrated problem effectively.3) The truck and trailer scheduling problem is researched. In this problem, the product is transported from warehouse to dock yard and the matching problem between trailers and products is considered because of the character that truck and trailer can be separated arbitrarily. This problem with multiple types of vehicles which can be assigned to different tasks more than one time is considered and the vehicle can also transport the products that don’t absolutely suit it. This problem is formulated as a mixed integer programming model to minimize the total cost by considering some practical factors, and the continuity of task and truck constraints are also considered. In this dissertation, the problem how to transport the last operation in appointed task is also analyzed and the property about the scheduling of last operation is put forward to optimize algorithm. An inherited composite neighborhood tabu search algorithm is developed to find a near-optimal scheduling where an initial solution is obtained based on the know-how knowledge. The results of experiment show that the proposed method could resolve the problem more effectively than current manual method.4) The coil stowage planning problem is researched. Comparing with the container stowage problem, it has its own features such as multi-wagon transportation mode, restriction on the minimum weight of loaded coils of each wagon, planning coils do not have to be loaded completely and more strict balance constraints than containers. Considering the features mentioned above, a novel integer programming model is established where the objectives are both to maximize the total weight of loaded coils and to minimize the total times of different sections and column of each two coils in wagons. The NP-hardness of the problem and intractableness of optimally solving the model motivate us to develop an improved tabu search algorithm to solve it approximately. The algorithm is initiated by a two-stage heuristic. The multi-exchange neighborhood is designed to increase the loaded coils and K-chains move is used in TS to be regard as a diversification strategy. All of experiment data are collected from transportation department of iron and steel enterprise and the experimental results comparing with CPLEX show that the proposed mathematical model and the tabu search algorithm can obtain better solutions than CPLEX in an allowable time and resolve the problem more effectively.5) The coil stowage planning problem for ship in a steel plant is researched. In this problem, it needs to be satisfied with the demand of ship loadage and stacking regular of coils in ship, the demand of ship stability of loading, sailing and unloading. Based on this, in order to minimize pick-up and unloading shift number, maximize the unloading efficiency, it should be fixed on the positions in ship of planning coils. For this problem of allocation planning coils in the hold of a ship, a mixed integer programming model based on the practical requirement is established, the objective function is to minimize the total cost by considering some practical issues and the different improved tabu search algorithms are designed to obtain the near-optimal solution based on different type of ship. A three-stage method according to the practical operation requests and experiences is proposed to obtain an initial solution, the intensification search strategy and two kinds of speed-up strategies are put forward to improve the search efficiency. The experimental results show that the proposed mathematical model and the tabu search algorithm can obtain satisfactory solutions in an allowable time and resolve the problem more effectively than current manual method.6) The stowage decision support system of ship and train transportation is designed and developed with taking the transportation logistics of iron and steel industry as the background. The established integer programming model based on practical problem and improved tabu search algorithms are embedded in system to solve the stowage planning problems of two different transportation modes, moreover the schedule edit system with graphical human-machine interaction interface is provided. For all of them, it realizes function of recording, adding, deleting and amending plan data, the function of auto-making plans and manual adjustment, the function of displaying plan with figure and evaluation. The system can help planners and dispatchers to set down the stowage plan for ship and train. By comparing the schedule generated by the system with the manual schedule, the stowage decision support system for ship and train is proved to be effective and it is running in a domestic steel plant to improve the dispatch efficiency of conveyance.