The efficiency of yard operations is critical to the overall productivity of a container terminal because the yard serves as the interface between the landside and waterside operations.Most container terminals use yar...The efficiency of yard operations is critical to the overall productivity of a container terminal because the yard serves as the interface between the landside and waterside operations.Most container terminals use yard cranes to transfer containers between the yard and trucks(both external and internal).To facilitate vessel operations,an efficient work schedule for the yard cranes is necessary given varying work volumes among yard blocks with different planning periods.This paper investigated an agent-based approach to assign and relocate yard cranes among yard blocks based on the forecasted work volumes.The goal of our study is to reduce the work volume that remains incomplete at the end of a planning period.We offered several preference functions for yard cranes and blocks which are modeled as agents.These preference functions are designed to find effective schedules for yard cranes.In addition,we examined various rules for the initial assignment of yard cranes to blocks.Our analysis demonstrated that our model can effectively and efficiently reduce the percentage of incomplete work volume for any real-world sized problem.展开更多
An optimization model for scheduling of quay cranes (QCs) and yard trailers was proposed to improve the overall efficiency of container terminals. To implement this model, a two-phase tabu search algorithm was designe...An optimization model for scheduling of quay cranes (QCs) and yard trailers was proposed to improve the overall efficiency of container terminals. To implement this model, a two-phase tabu search algorithm was designed. In the QCs scheduling phase of the algorithm, a search was performed to determine a good QC unloading operation order. For each QC unloading operation order generated during the QC's scheduling phase, another search was run to obtain a good yard trailer routing for the given QC's unloading order. Using this information, the time required for the operation was estimated, then the time of return to availability of the units was fed back to the QC scheduler. Numerical tests show that the two-phase Tabu Search algorithm searches the solution space efficiently, decreases the empty distance yard trailers must travel, decreases the number of trailers needed, and thereby reduces time and costs and improves the integration and reliability of container terminal operation systems.展开更多
Arranging the retrieving sequence and making the operational plans for gantry cranes to enhance port efficiency have become vital issues for the container terminals. In this paper, the problem of retrieving containers...Arranging the retrieving sequence and making the operational plans for gantry cranes to enhance port efficiency have become vital issues for the container terminals. In this paper, the problem of retrieving containers from a yard in a given sequence is discussed as an important part of the ship-loading process. This problem is divided into three categories according to its optimization complexity, i.e., the retrieval problem of a crane with a single spreader(ACSS), the retrieval problem of a crane with multiple spreaders(ACMS), and the retrieval problem of multiple cranes with a single spreader(MCSS). Firstly, heuristic algorithms are proposed to develop a retrieving sequence for ACSS to reduce the operational time. Then, optimizing the assignment to multiple spreaders is conducted by exchanging the movements of the obtained retrieving sequence. Finally, the movements are further assigned to two cranes and integrated with the MCSS retrieval problem mentioned above.The numerical experiments show the effectiveness and practicability of the heuristic algorithms.展开更多
Tide is a significant factor which interferes with the berthing and departing operations of vessels in tidal ports. It is a preferable way to incorporate this factor into the simultaneous berth allocation and quay cra...Tide is a significant factor which interferes with the berthing and departing operations of vessels in tidal ports. It is a preferable way to incorporate this factor into the simultaneous berth allocation and quay crane( QC) assignment problem( BACAP) in order to facilitate the realistic decision-making process at container terminal. For this purpose,an integrated optimization model is built with tidal time windows as forbidden intervals for berthing or departing. A hind-and-fore adjustment heuristic is proposed and applied under an iterative optimization framework. Numerical experiment shows the satisfying performance of the proposed algorithm.展开更多
文摘The efficiency of yard operations is critical to the overall productivity of a container terminal because the yard serves as the interface between the landside and waterside operations.Most container terminals use yard cranes to transfer containers between the yard and trucks(both external and internal).To facilitate vessel operations,an efficient work schedule for the yard cranes is necessary given varying work volumes among yard blocks with different planning periods.This paper investigated an agent-based approach to assign and relocate yard cranes among yard blocks based on the forecasted work volumes.The goal of our study is to reduce the work volume that remains incomplete at the end of a planning period.We offered several preference functions for yard cranes and blocks which are modeled as agents.These preference functions are designed to find effective schedules for yard cranes.In addition,we examined various rules for the initial assignment of yard cranes to blocks.Our analysis demonstrated that our model can effectively and efficiently reduce the percentage of incomplete work volume for any real-world sized problem.
文摘An optimization model for scheduling of quay cranes (QCs) and yard trailers was proposed to improve the overall efficiency of container terminals. To implement this model, a two-phase tabu search algorithm was designed. In the QCs scheduling phase of the algorithm, a search was performed to determine a good QC unloading operation order. For each QC unloading operation order generated during the QC's scheduling phase, another search was run to obtain a good yard trailer routing for the given QC's unloading order. Using this information, the time required for the operation was estimated, then the time of return to availability of the units was fed back to the QC scheduler. Numerical tests show that the two-phase Tabu Search algorithm searches the solution space efficiently, decreases the empty distance yard trailers must travel, decreases the number of trailers needed, and thereby reduces time and costs and improves the integration and reliability of container terminal operation systems.
基金the National Natural Science Foundation of China(No.71172108)the Doctoral Program Foundation of Institutions of Higher Education of China(Nos.20122125110009 and 20132125120009)the Dalian Science and Technology Project(No.2012A17GX125)
文摘Arranging the retrieving sequence and making the operational plans for gantry cranes to enhance port efficiency have become vital issues for the container terminals. In this paper, the problem of retrieving containers from a yard in a given sequence is discussed as an important part of the ship-loading process. This problem is divided into three categories according to its optimization complexity, i.e., the retrieval problem of a crane with a single spreader(ACSS), the retrieval problem of a crane with multiple spreaders(ACMS), and the retrieval problem of multiple cranes with a single spreader(MCSS). Firstly, heuristic algorithms are proposed to develop a retrieving sequence for ACSS to reduce the operational time. Then, optimizing the assignment to multiple spreaders is conducted by exchanging the movements of the obtained retrieving sequence. Finally, the movements are further assigned to two cranes and integrated with the MCSS retrieval problem mentioned above.The numerical experiments show the effectiveness and practicability of the heuristic algorithms.
基金National Natural Science Foundations of China(Nos.70771065,71171130,61473211,71502129)
文摘Tide is a significant factor which interferes with the berthing and departing operations of vessels in tidal ports. It is a preferable way to incorporate this factor into the simultaneous berth allocation and quay crane( QC) assignment problem( BACAP) in order to facilitate the realistic decision-making process at container terminal. For this purpose,an integrated optimization model is built with tidal time windows as forbidden intervals for berthing or departing. A hind-and-fore adjustment heuristic is proposed and applied under an iterative optimization framework. Numerical experiment shows the satisfying performance of the proposed algorithm.
