| With the rapid development of economic globalization in the past 30 years,international trade has become more and more frequent,and the container throughput of major ports in the world has also increased day by day,which has brought both opportunities and great challenges to all countries.In 2020,China’s container throughput reached 264 million TEU,ranking first in the world,indicating that China’s port scale and equipment and other hardware conditions have reached the world’s leading level,but there is still room for improvement in the aspects of modern operation and scheduling optimization.With the development of large-scale ship and the increase of container throughput,the contradiction between the existing storage yard resources and the increasing container throughput is becoming more and more serious.At present,only Shenzhen Port and Busan Port are available for yard expansion among all the major ports in the world.Therefore,in order to solve or alleviate this contradiction,it is necessary to improve the operation efficiency of the terminal and the utilization rate of yard space.As an important part of a port,the container terminal yard is a specialized area for handling,stacking and turnover of import and export containers,and plays an important role in the operation process of a terminal.With the shortage of terminal space resources,how to make the most reasonable use of the storage yard space resources has become the most concerned problem for terminal managers.The truck appointment system is widely used by major ports in the world to improve the utilization rate of terminal yard space resources.The terminal can issue reservation quota according to the actual situation of its own storage yard,and then trucks make reservations to allocate yard resources reasonably.However,due to traffic,weather or some man-made reasons,the reserved external truck often fail to arrive within the scheduled time period,that is,no-showing event occurs,which will lead to the increase of the number of reshuffles and gantry-crane traveling distance and the increase of the exhaust emissions from mechanical operation equipment and trucks in the actual operation process,leading to environmental pollution and the reduction of the operation efficiency of the terminal.Therefore,as an important link in the terminal operation process,the adjustment of the slot of the export containers directly affects the waiting time of ships in port,the efficiency of loading and unloading ships,and even the operation efficiency of the whole terminal.Therefore,the adjustment of the slot of export container is an urgent problem to be solved in ports today.For the problem of the adjustment of the slot of the export containers under no-showing events occurring,firstly,the normal distribution probability method is used to approximate simulate the arrival information of different no-showing levels of trucks.And on this basis,an optimization model with the goal of minimizing the number of reshuffles and gantry-crane traveling distance is constructed.Small scale numerical example experiments are solved with CPLEX,which proves the feasibility of the proposed model.According to the characteristics of the model in this paper,a heuristic algorithm based on neighborhood search is designed.At the same time,some large scale numerical example experiments are designed with different number of containers and different no-showing levels.Compared with the traditional operation algorithm,the numerical example experiments shows that the above method can reasonably arrange the slot of the export containers under no-showing events occurring and improve the operation efficiency of the terminal and obtain satisfactory solution within a reasonable time,which proves the feasibility of the model established in this paper and the effectiveness of the algorithm. |
