Simulated Annealing Based Algorithm For Cooperative Loading Ships In Container Terminal

Continuously driven by the process of the world economic integration,international trade has been developing rapidly,and container throughput of ports has continued to grow.Since China's reform and opening up,container transportation has also risen rapidly,and the container throughput of ports has become the first in the world.With the growth of the container throughput of ports and the large-scale trend for containership,the demand of shipping companies of containerships' operation efficiency and ability in ports is higher and higher.To seek a reasonable method to optimize loading schedule of vessels is in urgent need,in order to improve the operation efficiency of terminals,and enhance the competitiveness of ports.First,this paper makes a comprehensive introduce and analysis of related knowledge about the prestowage of slots,the containers' distribution in the yard and the specific process of loading operation under collaboration,which involved in the optimization problem of container terminal loading operation.It is clarified that this paper based on the prestowage,focus on the loading stage.On this basis,through detailed analysis of the constraint conditions of the problem,it makes reasonable simplifying assumptions,which defines clearly the content of research in this paper.And it regards minimizing the total equivalent time cost of the container terminal loading operation as the optimization goal.Based on the premise,the constraint conditions,and the characteristics of the problem,it designs corresponding heuristic rules to deal with optimizing the loading sequence and space arrangement at the same time,and collaboration of several yard cranes and quay cranes,which are two key problems of this paper.And through the designing of the codes,it combines the optimization problem with simulated annealing algorithm.Considering the shift of containers in the yard as well as the setting of the specific target function,it designs the heuristic rules to generate the initial solution and new solutions.It designs the simulated annealing algorithm to optimize the container terminal loading operation under collaboration of several yard cranes and quay cranes,which provides an innovative method and idea to the study of the problem of container terminal loading operation.Finally,the feasibility,convergence and validity of this algorithm are verified through theoretical and experimental analysis.First of all,the convergence,precision,and CPU time of the algorithm are analyzed.Results show that: 1)When the total cycle times reach 180000,total cost tends to be stable,and the algorithm converges.2)After converging,the total cost is reduced by about 36.8%.3)The CPU time is proportional to the total cycle number.4)When converging,the consumption of CPU time is 1437.568s(about 24min).Then the influence of related parameters of the algorithm is detailed analyzed.Results show that: 1)The algorithm can get a faster convergence speed with the inner cycle number L calculated according to temperature Tk then it fixed.2)The inner cycle number L makes no difference to the accuracy of the algorithm.3)The algorithm can get a faster convergence speed with a faster temperature decrement r.4)The algorithm can get a higher accuracy with a slower temperature decrement r.5)The algorithm can get a faster convergence speed with a lower initial temperature T0.6)The algorithm can get a higher accuracy with a higher initial temperature T0.7)The algorithm can get a faster convergence speed with a higher temperature Tf.8)The algorithm can get a higher accuracy with a lower temperature Tf.