Research On The Coordinated Optimization Between Berth Assignment And Yard Allocation Under Container Loading Operation

The container terminal is the buffer place for the containers to change the mode of transportation,and it is also the hub of land and water transportation,which plays an important role in the whole process of container transportation.As the key parts of container terminals,berth and yard play a vital role in container transportation.The berth and yard operation plans directly affect the operation efficiency of berths and yards,thereby affecting the operation efficiency and operation level of terminals.In addition,container loading process is an important part of container transportation.The loading efficiency is directly affected by the operation efficiency of berth and yard,and' also related to the operation level of the terminal.Therefore,it is of great significance to improve the efficiency of loading operation and meet the increasing demand of container transportation.In this research,the export container loading process is taken as the research object from two aspects of single vessel and multiple vessels.The coordinated optimization of berth assignment and yard allocation in the export container loading process is studied from the micro and macro perspectives.The main research work is as follows:(1)This research studies the collaborative optimization problem of the loading sequence and rehandling strategy.Based on the given containership Stowage plan and yard storage characteristics,the optimization strategy is presented considering the lowest stack strategy and nearest stack strategy.The influence of loading sequence and rehandling strategy on the yard rehandling operation is analyzed.The collaborative optimization model of the loading process and rehandling strategy is established to minimize the number of rehandles.In addition,the loading sequence and rehandling strategy are embedded into the genetic algorithm to study how to use an optimized rehandling strategy to determine the reasonable loading sequence to minimize the number of rehandles.Meanwhile,the numerical experiments are designed to compare with the existing heuristic algorithm,which is to indicate the effectiveness of the presented algorithm.Then,the significance test is used to verify the necessity of three rehandling strategies.Furtherly,the lower bound of the problem is discussed.The collaborative optimization problem is solved respectively under the single quay crane,double quay cranes and triple quay cranes,which is applied to verify the universality of the model and the algorithm.Therefore,this research is helpful to reduce the number of rehandles and to improve the loading efficiency in terminals.(2)The joint optimization model and algorithm of loading sequence and yard crane travel route is proposed.Considering the given containership stowage plan and yard stacking status,this research analyzes the interaction between loading sequence and yard crane travel route.The influence of them on the rehandling operation is further discussed.In addition,the yard crane operation time is applied to measure the loading sequence and yard crane travel route.Meanwhile,the joint optimization model is established aiming at minimizing the total operation time.Then,the rule-based algorithm is designed to solve the problem,which is to obtain the optimal loading sequence and yard crane travel route.Meanwhile,the lower bound of the joint optimization problem is proposed,which is applied to compare with the presented rule algorithm by different numerical experiments.It is verified that the algorithm is effective.Then,the joint optimization problem can effectively reduce the number of rehandles and shorten the yard crane operation time.(3)This research studies the coordinated optimization problem between berth assignment and yard allocation based on the truck travel route.The interaction between berth assignment and yard allocation during the export container loading process is analyzed.In addition,this research discusses the influence of vessel berthing position and container stacking layout on the truck travel distance.The coordinated optimization problem between berth assignment and yard allocation is studied and formulated as the mixed integer programming,which aims at minimizing the truck travel distance.The decision variables are the berthing positions for visiting vessels,the storage positions of export containers and the number of export containers stacking in each sub-block.Besides,the tabu genetic algorithm considering coordinated allocation process of berth and yard is designed to solve the coordinated optimization problem.This research further discusses the operational scenarios,which are to make the yard allocation plan under the determination of berth assignment,and to make the berth assignment plan under the determination of yard allocation.Numerical experiments results show that the number of berths,vessels and export containers directly affect the truck travel distance,the coordinated optimization between berth assignment and yard allocation can effectively shorten truck travel distance and improve terminal operation efficiency.(4)This research discusses the coordinated optimization problem between berth assignment and yard allocation based on the departure deviation of vessels.Considering the given estimated time of arrival and departure of the vessels,the influence of berth assignment and yard allocation plans on the actual departure time and operation time is analyzed.The coordinated optimization model is formulated combining with considering the operational constraints of berths,yards and loading,which aims at minimizing deviation between the actual departure time and the expected departure time.Then,the two-stage rule-based algorithm is designed to solve the problem to obtain the optimal berth assignment plan and yard allocation plan to minimize the deviation.In addition,the sensitivity analysis is applied to discuss the important factors affecting departure time deviation.The results show that the number of vessels,berths and the yard storage layout are important factors affecting departure time deviation.The terminal operators can achieve coordinated optimization between berth assignment and yard allocation on the basis of the departure deviation,so as to ensure the vessels leave on time and improve economic efficiency.Through the research on coordinated optimization between berth assignment and yard allocation under container loading operation,it shows that loading sequence,rehandling strategy and the yard crane travel route directly affect the yard rehandling operation.Meanwhile,the vessel berthing position,berthing time and the export container stacking position directly affect the truck travel route and vessel's time in port,and thus affect the efficiency of the loading operation.The comprehensive coordinated optimization of berth and yard operation is conducive to improving the efficiency of export container loading and further improving the efficiency of terminal operation.In addition,the coordinated optimization study will provide theoretical guidance and decision support for the terminal operator to make the loading plan,berth assignment plan and yard allocation plan.