This study discusses a yard planning system,which considers various resources such as storage space,yard cranes,and traffic areas in container terminals.The system is based on the function for estimating resource requ...This study discusses a yard planning system,which considers various resources such as storage space,yard cranes,and traffic areas in container terminals.The system is based on the function for estimating resource requirements of yard plans.For a given yard plan,the proposed system allows planners to check the feasibility of the plan which requires a certain amount of workload of resources in related blocks during a planning horizon.The yard planning system in this study is aimed at balancing workloads among the blocks and providing the ability to modify current yard plans by detecting blocks and periods with overloaded workloads.The system implements its planning function in a distributed manner in which planners construct yard plans under their individual control and send and receive only limited necessary information for the negotiation.展开更多
Land-use efficiency is essential in ports, in particular those that are constrained for space and experiencing congestion. In such situations, ports have been noted to invest in off-dock container yards. This study an...Land-use efficiency is essential in ports, in particular those that are constrained for space and experiencing congestion. In such situations, ports have been noted to invest in off-dock container yards. This study analysed land use efficiency of four off-dock yards located near the Port of Tema, Ghana’s largest seaport responsible for 85 percent of its trade. The study found that the terminals utilised 0.13 to 0.52 hectares of land, largely influenced by the dwell time and stacking height of containers. It was recommended that regulatory agencies need to coordinate better to reduce the time spent on cargo inspection and validation. In addition, terminals may need to incentivise customers to clear their import containers within shorter periods.展开更多
This paper proposes a mixed integer programming model for the allocation of rail mounted gantry cranes for four basic yard activities with different priorities. The model pays special attention to the typical features...This paper proposes a mixed integer programming model for the allocation of rail mounted gantry cranes for four basic yard activities with different priorities. The model pays special attention to the typical features of this kind of gantry cranes, such as a restricted traveling range and a limited number of adjustments during loading and discharging operations. In contrast to most of the literature dealing with these four yard activities individually, this paper models them into an integrated problem, whose computational complexity is proved to be NP-hard. We are therefore motivated to develop a Lagrangian relaxation-based heuristic to solve the problem. We compare the proposed heuristic with the branch-and-bound method that uses commercial software packages. Extensive computational results show that the proposed heuristic achieves competitive solution qualities for solving the tested problems.展开更多
This paper examines the yard truck scheduling,the yard location assignment for discharging containers,and the quay crane scheduling in container terminals.Taking into account the practical situation,we paid special at...This paper examines the yard truck scheduling,the yard location assignment for discharging containers,and the quay crane scheduling in container terminals.Taking into account the practical situation,we paid special attention to the loading and discharging precedence relationships between containers in the quay crane operations.A Mixed Integer Program（MIP） model is constructed,and a two-stage heuristic algorithm is proposed.In the first stage an Ant Colony Optimization（ACO） algorithm is employed to generate the yard location assignment for discharging containers.In the second stage,the integration of the yard truck scheduling and the quay crane scheduling is a flexible job shop problem,and an efficient greedy algorithm and a local search algorithm are proposed. Extensive numerical experiments are conducted to test the performance of the proposed algorithms.展开更多
An efcient approach for yard crane(YC)scheduling is proposed in this paper.The definition of task group for YC scheduling is proposed.A mixed integer programming(MIP)model is developed.In the model,objective functions...An efcient approach for yard crane(YC)scheduling is proposed in this paper.The definition of task group for YC scheduling is proposed.A mixed integer programming(MIP)model is developed.In the model,objective functions are subject to the minimization of the total delay of complete time for all task groups and the minimization of block-to-block movements of YCs.Due to the computational scale of the non-deterministic polynomial(NP)complete problem regarding YC scheduling,a rolling-horizon decision-making strategy is employed to solve this problem,by converting the MIP model into another MIP model in the scheduling of each rolling period.Afterwards,a heuristic algorithm based on modified A*search is developed to solve the converted model and obtain near optimal solution.Finally,the computational experiments are used to examine the performance of the proposed approach for YC scheduling.展开更多
基金Project supported by the Korean Ministry of Education,Science and Technology Grant (the Regional Core Research Program/Institute of Logistics Information Technology)
文摘This study discusses a yard planning system,which considers various resources such as storage space,yard cranes,and traffic areas in container terminals.The system is based on the function for estimating resource requirements of yard plans.For a given yard plan,the proposed system allows planners to check the feasibility of the plan which requires a certain amount of workload of resources in related blocks during a planning horizon.The yard planning system in this study is aimed at balancing workloads among the blocks and providing the ability to modify current yard plans by detecting blocks and periods with overloaded workloads.The system implements its planning function in a distributed manner in which planners construct yard plans under their individual control and send and receive only limited necessary information for the negotiation.
文摘Land-use efficiency is essential in ports, in particular those that are constrained for space and experiencing congestion. In such situations, ports have been noted to invest in off-dock container yards. This study analysed land use efficiency of four off-dock yards located near the Port of Tema, Ghana’s largest seaport responsible for 85 percent of its trade. The study found that the terminals utilised 0.13 to 0.52 hectares of land, largely influenced by the dwell time and stacking height of containers. It was recommended that regulatory agencies need to coordinate better to reduce the time spent on cargo inspection and validation. In addition, terminals may need to incentivise customers to clear their import containers within shorter periods.
基金supported by the National Nature Science Foundation of China under grant numbers 71102011and 51105394Guangdong provincial department of science and technology(Number 2011B090400384)
文摘This paper proposes a mixed integer programming model for the allocation of rail mounted gantry cranes for four basic yard activities with different priorities. The model pays special attention to the typical features of this kind of gantry cranes, such as a restricted traveling range and a limited number of adjustments during loading and discharging operations. In contrast to most of the literature dealing with these four yard activities individually, this paper models them into an integrated problem, whose computational complexity is proved to be NP-hard. We are therefore motivated to develop a Lagrangian relaxation-based heuristic to solve the problem. We compare the proposed heuristic with the branch-and-bound method that uses commercial software packages. Extensive computational results show that the proposed heuristic achieves competitive solution qualities for solving the tested problems.
基金supported by the National Nature Science Foundation of China under grant no.71102011
文摘This paper examines the yard truck scheduling,the yard location assignment for discharging containers,and the quay crane scheduling in container terminals.Taking into account the practical situation,we paid special attention to the loading and discharging precedence relationships between containers in the quay crane operations.A Mixed Integer Program（MIP） model is constructed,and a two-stage heuristic algorithm is proposed.In the first stage an Ant Colony Optimization（ACO） algorithm is employed to generate the yard location assignment for discharging containers.In the second stage,the integration of the yard truck scheduling and the quay crane scheduling is a flexible job shop problem,and an efficient greedy algorithm and a local search algorithm are proposed. Extensive numerical experiments are conducted to test the performance of the proposed algorithms.
基金the National Natural Science Foundation of China(No.71101090)the Shanghai Top Academic Discipline Project-Management Science&Engineering,the Shanghai Municipal Education Commission Project(Nos.12ZZ148,13YZ080 and 14YZ112)+1 种基金the Ministry of Transport Research Projects(No.2012-329-810-180)the Shanghai Maritime University Research Project(Nos.20120102 and 20110019)
文摘An efcient approach for yard crane(YC)scheduling is proposed in this paper.The definition of task group for YC scheduling is proposed.A mixed integer programming(MIP)model is developed.In the model,objective functions are subject to the minimization of the total delay of complete time for all task groups and the minimization of block-to-block movements of YCs.Due to the computational scale of the non-deterministic polynomial(NP)complete problem regarding YC scheduling,a rolling-horizon decision-making strategy is employed to solve this problem,by converting the MIP model into another MIP model in the scheduling of each rolling period.Afterwards,a heuristic algorithm based on modified A*search is developed to solve the converted model and obtain near optimal solution.Finally,the computational experiments are used to examine the performance of the proposed approach for YC scheduling.
