Research On The Optimization Of Containers' Location Allocation For Rear Yard Of Container Wharf

Yard is an important part of harbour logistics.The plan of stacking containers in the yard can affect operation efficiency and cost-effective of wharf. Studying and formulating a reasonable stack strategy is propitious to reduce the cost of machine, reduce the time of operation in yard,increase the speed of loading and unloading ships,and then increase the capability of stacking containers of yard because of reducing the times of turning containers.Container yard is separated into front yard and rear yard.This study focuses on the stacking strategy of rear yard which domestic and foreign scholars pay less attention to.The containers belongs to different bill of lading No. and cargo owner are assigned to different BAY in the traditional strategy.The traditional strategy can reduce times of turning containers,but it also lead to the waste of space. This article is to study how to assign locations for containers to minimize the times of turning containers with the technology of mixed stack,which the containers belongs different bill of lading No. and cargo owner are assigned to the same BAY,when a group of containers arrive in the rear yard randomly. In this article,the actual question is predigested in some degree.And the allocation model for containers in rear yard, which is limited by time of picking up containers and aims at the minimal container-turned rate, is proposed.Since the problem is known to be a NP-hard one,it is very difficult thar solve it by using traditional optimize methods.Firstly, Genetic Algorithm is chosen to solve this quesetion.The defect of Genetic Algorithm in other article which optimizes each container is analyzed,and a new strategy which optimizes a group of containers is proposed. All the GA's steps are improved for the best result. Then,the Strategy is proved advantage by comparison with other genetic algorithms which we referred in different actual.Then, Heuristic method which is efficient is chosen to solve this problem because of the inefficient of Genetic Algorithm.Three Heuristic rules is developed by the analysis of the relationship between the priority of containers and turning containers, and the Heuristic method is described according to the rules. Heuristic method is proved high efficiency but somewhat weaker effect of the characteristics by comparison with other two methods.The two points have different advantage, the advantage of Genetic Algorithm is better optimization result,and the advantage of Heuristic method is better efficiency.An optimization scheme which is used to slove practical problems is wished to not noly good optimizing result but also operating efficiency.Thus,a new strategy which combines Genetic Algorithm and Heuristic method is proposed.The new strategy is that Heuristic method is used when there are less containers in the yard, and Genetic Algorithm is used in other case.The new strategy is proved practical when optimizing result and operating efficiency are both considered by comparison with other three methods.