Improving the cooperative scheduling efficiency of equipment is the key for automated container terminals to copewith the development trend of large-scale ships. In order to improve the solution efficiency of the exis...Improving the cooperative scheduling efficiency of equipment is the key for automated container terminals to copewith the development trend of large-scale ships. In order to improve the solution efficiency of the existing spacetimenetwork (STN) model for the cooperative scheduling problem of yard cranes (YCs) and automated guidedvehicles (AGVs) and extend its application scenarios, two improved STN models are proposed. The flow balanceconstraints in the original model are decomposed, and the trajectory constraints of YCs and AGVs are added toacquire the model STN_A. The coupling constraint in STN_A is updated, and buffer constraints are added toSTN_A so that themodel STN_B is built.As the size of the problem increases, the solution speed of CPLEX becomesthe bottleneck. So a heuristic method containing three groups of heuristic rules is designed to obtain a near-optimalsolution quickly. Experimental results showthat the computation time of STN_A is shortened by 49.47% on averageand the gap is reduced by 1.69% on average compared with the original model. The gap between the solution ofthe heuristic rules and the solution of CPLEX is less than 3.50%, and the solution time of the heuristic rules is onaverage 99.85% less than the solution time of CPLEX. Compared with STN_A, the computation time for solvingSTN_B increases by 58.93% on average.展开更多
Marine container terminal(MCT)plays a key role in the marine intelligent transportation system and international logistics system.However,the efficiency of resource scheduling significantly influences the operation pe...Marine container terminal(MCT)plays a key role in the marine intelligent transportation system and international logistics system.However,the efficiency of resource scheduling significantly influences the operation performance of MCT.To solve the practical resource scheduling problem(RSP)in MCT efficiently,this paper has contributions to both the problem model and the algorithm design.Firstly,in the problem model,different from most of the existing studies that only consider scheduling part of the resources in MCT,we propose a unified mathematical model for formulating an integrated RSP.The new integrated RSP model allocates and schedules multiple MCT resources simultaneously by taking the total cost minimization as the objective.Secondly,in the algorithm design,a pre-selection-based ant colony system(PACS)approach is proposed based on graphic structure solution representation and a pre-selection strategy.On the one hand,as the RSP can be formulated as the shortest path problem on the directed complete graph,the graphic structure is proposed to represent the solution encoding to consider multiple constraints and multiple factors of the RSP,which effectively avoids the generation of infeasible solutions.On the other hand,the pre-selection strategy aims to reduce the computational burden of PACS and to fast obtain a higher-quality solution.To evaluate the performance of the proposed novel PACS in solving the new integrated RSP model,a set of test cases with different sizes is conducted.Experimental results and comparisons show the effectiveness and efficiency of the PACS algorithm,which can significantly outperform other state-of-the-art algorithms.展开更多
The most prominent risk assessment techniques are founded on the values of measuring and controlling the frequency and the consequences of risks in order to assure an“acceptable level”of“safeness”mainly in the lin...The most prominent risk assessment techniques are founded on the values of measuring and controlling the frequency and the consequences of risks in order to assure an“acceptable level”of“safeness”mainly in the lines of environmental,health and hygiene and port product issues.This paper examines security risk assessment approaches within the emerging role of ports.This paper contributes to the current literature by considering the ports of Greece as a case in point and by measuring the degree of its security risk orientation based on certain valid risk factors drawn from the current literature.Moreover,it presents a security risk assessment methodology into the domain of port container terminals.Their potential for ports were quantitatively and qualitatively assessed by discussing issues of security approaches within the maritime industry,in order to facilitate improvement strategies.A two-dimension empirical study was conducted,in a time range of ten years(2010-2020)in order to provide evidence regarding security risk assessment in the port container terminal of Thessaloniki,in Greece.The findings of this study have significant strategic policy implications and shed more light on the role of security risks in the overall risk orientation of container terminals in practice.Finally,further research directions in security risk in ports are proposed.展开更多
The similarities and differences between the container terminal logistics system(CTLS)and the Harvard-architecture computer system are compared in terms of organization and architecture.The mapping relation and the mo...The similarities and differences between the container terminal logistics system(CTLS)and the Harvard-architecture computer system are compared in terms of organization and architecture.The mapping relation and the modeling framework of the CTLS are presented based on multi-agent,and the successful algorithms in the computer domain are applied to the modeling framework,such as the dynamic priority and multilevel feedback scheduling algorithm.In addition,a model and simulation on a certain quay at Shanghai harbor is built up on the AnyLogic platform to support the decision-making of terminal on service cost.It validates the feasibility and creditability of the above systematic methodology.展开更多
The uninterrupted operation of the quay crane(QC)ensures that the large container ship can depart port within laytime,which effectively reduces the handling cost for the container terminal and ship owners.The QC waiti...The uninterrupted operation of the quay crane(QC)ensures that the large container ship can depart port within laytime,which effectively reduces the handling cost for the container terminal and ship owners.The QC waiting caused by automated guided vehicles(AGVs)delay in the uncertain environment can be alleviated by dynamic scheduling optimization.A dynamic scheduling process is introduced in this paper to solve the AGV scheduling and path planning problems,in which the scheduling scheme determines the starting and ending nodes of paths,and the choice of paths between nodes affects the scheduling of subsequent AGVs.This work proposes a two-stage mixed integer optimization model to minimize the transportation cost of AGVs under the constraint of laytime.A dynamic optimization algorithm,including the improved rule-based heuristic algorithm and the integration of the Dijkstra algorithm and the Q-Learning algorithm,is designed to solve the optimal AGV scheduling and path schemes.A new conflict avoidance strategy based on graph theory is also proposed to reduce the probability of path conflicts between AGVs.Numerical experiments are conducted to demonstrate the effectiveness of the proposed model and algorithm over existing methods.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
Nowadays, the most prominent risk assessment techniques are founded on the values of measuring and controlling the frequency and the consequences of risks in order to assure an "acceptable level" of "safeness" mai...Nowadays, the most prominent risk assessment techniques are founded on the values of measuring and controlling the frequency and the consequences of risks in order to assure an "acceptable level" of "safeness" mainly in the lines of environmental, health and hygiene and port product issues. This paper initially introduces risk assessment approaches within the emerging role of ports Thereafter, it qualitatively assesses their potential for ports by discussing issues challenging every safety and security approach within the maritime industry such as proactiveness, organization, transparency, cost-effectiveness and, when possible, calibration to specific experiences. Moreover, an empirical study was conducted in order to provide evidence for formal risk assessment for safety and security in the main Greek port container terminals of Piraeus and Thessaloniki. The empirical research is based on in-depth semi-structured interviews with the administrations of container terminals. The results include important findings, regarding the likelihood of appearance of certain risks and their perceived severity in Greek container terminals. The collected answers and their analysis are also important for confirming the suggested theoretical formal risk assessment framework for ports.展开更多
This paper empirically evaluates container terminal service attributes. The methodology proposed focuses on statistical control, Based on the concept of service segmentation, the authors employed control charts to cla...This paper empirically evaluates container terminal service attributes. The methodology proposed focuses on statistical control, Based on the concept of service segmentation, the authors employed control charts to classify container terminal services. The purpose of control charts is to allow simple detection of events that are indicative of actual process change. This simple decision can be difficult where the process characteristic is continuously varying, the control chart provides statistically objective criteria of change. When change is detected and considered good its cause should be identified and possibly become the new way of working, where the change is bad then its cause should be identified and eliminated. Both theoretical and practical implications of the research findings are discussed in this paper.展开更多
Amidst the ever increasing demand for the unhindered flow of freight throughout the world, seaport safety is emerging as a critical factor which increasingly dictates the need to establish a proactive approach towards...Amidst the ever increasing demand for the unhindered flow of freight throughout the world, seaport safety is emerging as a critical factor which increasingly dictates the need to establish a proactive approach towards addressing the associated risks rather than the traditional reactive response to port accidents. This paper proposes and presents a proactive methodology for port safety risk assessment (including the techno-economically effective prioritized control) which constitutes an adaptation of the FSA (Formal Safety Assessment) for ships. The ability of the proposed methodology to offer this standardized approach for PRA (Port Risk Assessment) is demonstrated through reference to the container terminal of the Greek Port of Thessalonica, for which an empirical study is contacted utilizing the historical record of encountered accidents with regard to their frequency of occurrence and their impact upon the human and environmental resources of the port.展开更多
Low performance of operational practices and wrong perceptions on demand forecast cause improper investments on new facilities for containers terminals, without taking into account the best use of their available reso...Low performance of operational practices and wrong perceptions on demand forecast cause improper investments on new facilities for containers terminals, without taking into account the best use of their available resources. Accordingly, it would be desirable to model dynamic behaviour among demand, capacity and productivity of container terminal services, like reception, storage and distribution, to forecast their performances faced to demand evolution with time. This paper presents a system dynamic model to evaluate impacts from demand variations on 18 container terminals associated to ABRATEC (Associa^do Brasileira dos Terminals de Cont^ineres de Uso P^blico (in English: Brazilian Association of Public Container Terminals)) and their response capability to compensate demand growth with increasing productivity. The behaviour of the developed dynamic models was demonstrated by means of simulations carried out with the Vensim Standard 5.6d system dynamics software.展开更多
As the ports play a prominent role in the national economy of the countries and a number of factors such as safety condition of the port and low rate or non-occurrence of accidents are greatly important for being sele...As the ports play a prominent role in the national economy of the countries and a number of factors such as safety condition of the port and low rate or non-occurrence of accidents are greatly important for being selected as a destination for cargo owners to bring their vessels and cargo therein, giving due care to safety related issues in ports and harbors is among jurisdictional and sensitive duties of the authorities in ports and maritime areas. Enjoying some 3000 km of marine coastlines and more than 10 commercial ports throughout the country, Iran is no exception where its ports are responsible for cargo import and export. In this respect, container terminals are one of the high-risk areas in ports requiring extensive care of the pertaining authorities to take appropriate measures to maintain safety standard there. One of the significant methods and techniques for the risk assessment is P&HRAM as to the containers terminals. This method has been employed in this research taking into account the operation attributes of the works in ports and harbors. This method provided appropriate answers to the research questions in that it was predicted that the great part of the activities in container terminal poses a higher risk from human perspective than expected requiring some measures to be taken to mitigate the risks to a tolerable level. This research was conducted and the results demonstrated that more than 75% of the risks in container terminals are higher than acceptable level about which some measures were taken and the risks were reduced to 100% lower than tolerable level.展开更多
Year of 1999 is the year of 50th anniversary of the founding of the People’s Republic of China, and 100th anniversary of the founding of Dalian City and port of Dalian. This year, Dalian Container Terminal Co. Ltd. (...Year of 1999 is the year of 50th anniversary of the founding of the People’s Republic of China, and 100th anniversary of the founding of Dalian City and port of Dalian. This year, Dalian Container Terminal Co. Ltd. (DCT) will also celebrate its 3rd anniversary of founding. On behalf of all DCT staff, I would llke to express our gratitude to all the friends and our business patroness. DCT is a joint venture between PSA Corporations and Port of Dalian Authority and commenced perations on July 1, 1996. In the past three years, with support from relevant communities, DCT has been growing up gradually. Recently, DCT was awarded the "Best Container Terminal Operator" in 13th Asian Freight Industry Awards, and ranked 11th in Asian Ports in terms of cargo volumes handled. DCT is the only Chinese Mainland port to achieve the honor.展开更多
For automated container terminals,the effective integrated scheduling of different kinds of equipment such as quay cranes(QCs),automated guided vehicles(AGVs),and yard cranes(YCs)is of great significance in reducing e...For automated container terminals,the effective integrated scheduling of different kinds of equipment such as quay cranes(QCs),automated guided vehicles(AGVs),and yard cranes(YCs)is of great significance in reducing energy consumption and achieving sustainable development.Aiming at the joint scheduling of AGVs and YCs with consideration of conflict-free path planning for AGVs as well as capacity constraints on AGV-mate which is also called buffer bracket in blocks,a mixed integer programming model is established to minimize the energy consumption of AGVs and YCs for the given loading/unloading task.A solution method based on a novel bi-level genetic algorithm(BGA),in which the outer and the inner layer search the optimal dispatching strategy for QCs and YCs,respectively,is designed.The validity of the model and the algorithm is verified by simulation experiments,which take the Port of Qingdao as an example and the performance under different conflicting resolution strategies is compared.The results show that,for the given task,the proposed solution to conflict-free path and the schedule provided by the algorithm can complete the task with minimum energy consumption without loss of AGVs utilization,and the number of AGV-mates should be adjusted according to the task rather than keeping unchanged.Comparison results indicate that our proposed approach could efficiently find solutions within 6%optimality gaps.Energy consumption is dropped by an average of 15%.展开更多
The throughput capacity of a container terminal is very important in planning and designing at container terminals.The existing methods estimated the throughput capacity without considering its change resulting from t...The throughput capacity of a container terminal is very important in planning and designing at container terminals.The existing methods estimated the throughput capacity without considering its change resulting from the different combination patterns of the types of arriving vessels.A simulation model is established to estimate the throughput capacities of a container terminal under different combination patterns of the types of arriving vessels.It shows that the throughput capacity of a container terminal is influenced by the utilization rates of the berth and quay cranes which result from the different combination patterns of the types of the arriving vessels.It provides a practical approach to estimate the throughput capacity of a container terminal considering the types of the vessels,and it is also helpful for the decision makers to raise the throughputs of the container terminals by optimizing the combination patterns of the types of arriving vessels.展开更多
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
The freight logistics includes all the processes needed to supply industry,retailers and wholesalers and final customers with goods.Such processes generate a flow of goods that,in the global supply chain,mainly relies...The freight logistics includes all the processes needed to supply industry,retailers and wholesalers and final customers with goods.Such processes generate a flow of goods that,in the global supply chain,mainly relies on the activities carried out within worldwide container terminals.In this paper,the authors present a simulation model of a real container terminal.After some preliminary analyses,the simulation model is first used with Design of Experiments and Analysis of Variance to investigate the effects of different resources allocations(i.e.,number of forklifts and tractors)and some parameters(i.e.,inter-arrival times,container unloading time)on the container terminal performances in terms of total number of handled containers per day.Then,based on the results achieved through the Design of Experiments and Analysis of Variance,the simulation model is used with genetic algorithms to carry out a range allocation optimization on berth assignment to incoming ships and number of tractors serving each quay crane.The aim of the optimization is the minimization of the average time spent by each ship in the port area(decreasing,as consequence,costs and increasing service level provided to final customers).展开更多
An integrated model is presented to schedule the container handling system. The objective is to improve the coop- eration between different types of equipments, and to increase the productivity of the terminal. The pr...An integrated model is presented to schedule the container handling system. The objective is to improve the coop- eration between different types of equipments, and to increase the productivity of the terminal. The problem is formulated as a Hybrid Flow Shop Scheduling problem with precedence constraint, setup times and blocking (HFSS-B). A tabu search algorithm is proposed to solve this problem. The quality and efficiency of the proposed algorithm is analyzed from the computational point of view.展开更多
In this paper, we apply the split-platform automated storage/retrieval systems (SP-AS/RSs) (Hu et al., 2005) to store containers in the yard to improve the yard performance and to increase the utilization of the yard ...In this paper, we apply the split-platform automated storage/retrieval systems (SP-AS/RSs) (Hu et al., 2005) to store containers in the yard to improve the yard performance and to increase the utilization of the yard space. The layout of an SP-AS/RS based yard is described in detail. To achieve an efficient operation, we present a novel yard space allocation policy called the ‘second-carrier-based allocation policy’, which can help to alleviate the out-of-sequence problem of containers and the congestion of vehicles at the AS/RS racks. Different allocation policies are compared by an integrated container terminal simulation system. The simulation results show that the second-carrier-based policy is very efficient and has the potential to offer high terminal performance.展开更多
The integrated berth-crane allocation problem at container terminals is addressed under the uncertainty of vessel arrival time at operational level. To ensure both robustness and flexibility of the 2-stage decision pr...The integrated berth-crane allocation problem at container terminals is addressed under the uncertainty of vessel arrival time at operational level. To ensure both robustness and flexibility of the 2-stage decision processes,a dynamic decision framework is proposed based on the dynamic analysis of information and operation at container terminal. A mixed integer programming model is established aiming at minimizing total cost of all vessels,including the cost of fixed to-be-executed decisions in the 1^(st) stage and expected cost of the adjustable stochastic-scenario-based decisions of all scenarios in the 2^(nd) stage. A multi-layer nested Tabu search is proposed for each epoch dynamically. Finally numerical experiments have been conducted to testify the effectiveness and efficiency of the proposed model and algorithm.展开更多
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
基金National Natural Science Foundation of China(62073212).
文摘Improving the cooperative scheduling efficiency of equipment is the key for automated container terminals to copewith the development trend of large-scale ships. In order to improve the solution efficiency of the existing spacetimenetwork (STN) model for the cooperative scheduling problem of yard cranes (YCs) and automated guidedvehicles (AGVs) and extend its application scenarios, two improved STN models are proposed. The flow balanceconstraints in the original model are decomposed, and the trajectory constraints of YCs and AGVs are added toacquire the model STN_A. The coupling constraint in STN_A is updated, and buffer constraints are added toSTN_A so that themodel STN_B is built.As the size of the problem increases, the solution speed of CPLEX becomesthe bottleneck. So a heuristic method containing three groups of heuristic rules is designed to obtain a near-optimalsolution quickly. Experimental results showthat the computation time of STN_A is shortened by 49.47% on averageand the gap is reduced by 1.69% on average compared with the original model. The gap between the solution ofthe heuristic rules and the solution of CPLEX is less than 3.50%, and the solution time of the heuristic rules is onaverage 99.85% less than the solution time of CPLEX. Compared with STN_A, the computation time for solvingSTN_B increases by 58.93% on average.
基金This research was supported in part by the National Key Research and Development Program of China under Grant 2022YFB3305303in part by the National Natural Science Foundations of China(NSFC)under Grant 62106055+1 种基金in part by the Guangdong Natural Science Foundation under Grant 2022A1515011825in part by the Guangzhou Science and Technology Planning Project under Grants 2023A04J0388 and 2023A03J0662.
文摘Marine container terminal(MCT)plays a key role in the marine intelligent transportation system and international logistics system.However,the efficiency of resource scheduling significantly influences the operation performance of MCT.To solve the practical resource scheduling problem(RSP)in MCT efficiently,this paper has contributions to both the problem model and the algorithm design.Firstly,in the problem model,different from most of the existing studies that only consider scheduling part of the resources in MCT,we propose a unified mathematical model for formulating an integrated RSP.The new integrated RSP model allocates and schedules multiple MCT resources simultaneously by taking the total cost minimization as the objective.Secondly,in the algorithm design,a pre-selection-based ant colony system(PACS)approach is proposed based on graphic structure solution representation and a pre-selection strategy.On the one hand,as the RSP can be formulated as the shortest path problem on the directed complete graph,the graphic structure is proposed to represent the solution encoding to consider multiple constraints and multiple factors of the RSP,which effectively avoids the generation of infeasible solutions.On the other hand,the pre-selection strategy aims to reduce the computational burden of PACS and to fast obtain a higher-quality solution.To evaluate the performance of the proposed novel PACS in solving the new integrated RSP model,a set of test cases with different sizes is conducted.Experimental results and comparisons show the effectiveness and efficiency of the PACS algorithm,which can significantly outperform other state-of-the-art algorithms.
文摘The most prominent risk assessment techniques are founded on the values of measuring and controlling the frequency and the consequences of risks in order to assure an“acceptable level”of“safeness”mainly in the lines of environmental,health and hygiene and port product issues.This paper examines security risk assessment approaches within the emerging role of ports.This paper contributes to the current literature by considering the ports of Greece as a case in point and by measuring the degree of its security risk orientation based on certain valid risk factors drawn from the current literature.Moreover,it presents a security risk assessment methodology into the domain of port container terminals.Their potential for ports were quantitatively and qualitatively assessed by discussing issues of security approaches within the maritime industry,in order to facilitate improvement strategies.A two-dimension empirical study was conducted,in a time range of ten years(2010-2020)in order to provide evidence regarding security risk assessment in the port container terminal of Thessaloniki,in Greece.The findings of this study have significant strategic policy implications and shed more light on the role of security risks in the overall risk orientation of container terminals in practice.Finally,further research directions in security risk in ports are proposed.
基金The National Key Technology R&D Program of China during the 11th Five-Year Plan Period(No.2006BAH02A06)
文摘The similarities and differences between the container terminal logistics system(CTLS)and the Harvard-architecture computer system are compared in terms of organization and architecture.The mapping relation and the modeling framework of the CTLS are presented based on multi-agent,and the successful algorithms in the computer domain are applied to the modeling framework,such as the dynamic priority and multilevel feedback scheduling algorithm.In addition,a model and simulation on a certain quay at Shanghai harbor is built up on the AnyLogic platform to support the decision-making of terminal on service cost.It validates the feasibility and creditability of the above systematic methodology.
基金supported in part by the National Natural Science Foundation of China(61473053)the Science and Technology Innovation Foundation of Dalian,China(2020JJ26GX033)。
文摘The uninterrupted operation of the quay crane(QC)ensures that the large container ship can depart port within laytime,which effectively reduces the handling cost for the container terminal and ship owners.The QC waiting caused by automated guided vehicles(AGVs)delay in the uncertain environment can be alleviated by dynamic scheduling optimization.A dynamic scheduling process is introduced in this paper to solve the AGV scheduling and path planning problems,in which the scheduling scheme determines the starting and ending nodes of paths,and the choice of paths between nodes affects the scheduling of subsequent AGVs.This work proposes a two-stage mixed integer optimization model to minimize the transportation cost of AGVs under the constraint of laytime.A dynamic optimization algorithm,including the improved rule-based heuristic algorithm and the integration of the Dijkstra algorithm and the Q-Learning algorithm,is designed to solve the optimal AGV scheduling and path schemes.A new conflict avoidance strategy based on graph theory is also proposed to reduce the probability of path conflicts between AGVs.Numerical experiments are conducted to demonstrate the effectiveness of the proposed model and algorithm over existing methods.
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.
文摘Nowadays, the most prominent risk assessment techniques are founded on the values of measuring and controlling the frequency and the consequences of risks in order to assure an "acceptable level" of "safeness" mainly in the lines of environmental, health and hygiene and port product issues. This paper initially introduces risk assessment approaches within the emerging role of ports Thereafter, it qualitatively assesses their potential for ports by discussing issues challenging every safety and security approach within the maritime industry such as proactiveness, organization, transparency, cost-effectiveness and, when possible, calibration to specific experiences. Moreover, an empirical study was conducted in order to provide evidence for formal risk assessment for safety and security in the main Greek port container terminals of Piraeus and Thessaloniki. The empirical research is based on in-depth semi-structured interviews with the administrations of container terminals. The results include important findings, regarding the likelihood of appearance of certain risks and their perceived severity in Greek container terminals. The collected answers and their analysis are also important for confirming the suggested theoretical formal risk assessment framework for ports.
文摘This paper empirically evaluates container terminal service attributes. The methodology proposed focuses on statistical control, Based on the concept of service segmentation, the authors employed control charts to classify container terminal services. The purpose of control charts is to allow simple detection of events that are indicative of actual process change. This simple decision can be difficult where the process characteristic is continuously varying, the control chart provides statistically objective criteria of change. When change is detected and considered good its cause should be identified and possibly become the new way of working, where the change is bad then its cause should be identified and eliminated. Both theoretical and practical implications of the research findings are discussed in this paper.
文摘Amidst the ever increasing demand for the unhindered flow of freight throughout the world, seaport safety is emerging as a critical factor which increasingly dictates the need to establish a proactive approach towards addressing the associated risks rather than the traditional reactive response to port accidents. This paper proposes and presents a proactive methodology for port safety risk assessment (including the techno-economically effective prioritized control) which constitutes an adaptation of the FSA (Formal Safety Assessment) for ships. The ability of the proposed methodology to offer this standardized approach for PRA (Port Risk Assessment) is demonstrated through reference to the container terminal of the Greek Port of Thessalonica, for which an empirical study is contacted utilizing the historical record of encountered accidents with regard to their frequency of occurrence and their impact upon the human and environmental resources of the port.
文摘Low performance of operational practices and wrong perceptions on demand forecast cause improper investments on new facilities for containers terminals, without taking into account the best use of their available resources. Accordingly, it would be desirable to model dynamic behaviour among demand, capacity and productivity of container terminal services, like reception, storage and distribution, to forecast their performances faced to demand evolution with time. This paper presents a system dynamic model to evaluate impacts from demand variations on 18 container terminals associated to ABRATEC (Associa^do Brasileira dos Terminals de Cont^ineres de Uso P^blico (in English: Brazilian Association of Public Container Terminals)) and their response capability to compensate demand growth with increasing productivity. The behaviour of the developed dynamic models was demonstrated by means of simulations carried out with the Vensim Standard 5.6d system dynamics software.
文摘As the ports play a prominent role in the national economy of the countries and a number of factors such as safety condition of the port and low rate or non-occurrence of accidents are greatly important for being selected as a destination for cargo owners to bring their vessels and cargo therein, giving due care to safety related issues in ports and harbors is among jurisdictional and sensitive duties of the authorities in ports and maritime areas. Enjoying some 3000 km of marine coastlines and more than 10 commercial ports throughout the country, Iran is no exception where its ports are responsible for cargo import and export. In this respect, container terminals are one of the high-risk areas in ports requiring extensive care of the pertaining authorities to take appropriate measures to maintain safety standard there. One of the significant methods and techniques for the risk assessment is P&HRAM as to the containers terminals. This method has been employed in this research taking into account the operation attributes of the works in ports and harbors. This method provided appropriate answers to the research questions in that it was predicted that the great part of the activities in container terminal poses a higher risk from human perspective than expected requiring some measures to be taken to mitigate the risks to a tolerable level. This research was conducted and the results demonstrated that more than 75% of the risks in container terminals are higher than acceptable level about which some measures were taken and the risks were reduced to 100% lower than tolerable level.
文摘Year of 1999 is the year of 50th anniversary of the founding of the People’s Republic of China, and 100th anniversary of the founding of Dalian City and port of Dalian. This year, Dalian Container Terminal Co. Ltd. (DCT) will also celebrate its 3rd anniversary of founding. On behalf of all DCT staff, I would llke to express our gratitude to all the friends and our business patroness. DCT is a joint venture between PSA Corporations and Port of Dalian Authority and commenced perations on July 1, 1996. In the past three years, with support from relevant communities, DCT has been growing up gradually. Recently, DCT was awarded the "Best Container Terminal Operator" in 13th Asian Freight Industry Awards, and ranked 11th in Asian Ports in terms of cargo volumes handled. DCT is the only Chinese Mainland port to achieve the honor.
基金This study is supported by the Natural Science Foundation of China under Grant Nos.61673228 and 61072260the Science Technology Program of Qingdao(21-1-2-16-zhz).
文摘For automated container terminals,the effective integrated scheduling of different kinds of equipment such as quay cranes(QCs),automated guided vehicles(AGVs),and yard cranes(YCs)is of great significance in reducing energy consumption and achieving sustainable development.Aiming at the joint scheduling of AGVs and YCs with consideration of conflict-free path planning for AGVs as well as capacity constraints on AGV-mate which is also called buffer bracket in blocks,a mixed integer programming model is established to minimize the energy consumption of AGVs and YCs for the given loading/unloading task.A solution method based on a novel bi-level genetic algorithm(BGA),in which the outer and the inner layer search the optimal dispatching strategy for QCs and YCs,respectively,is designed.The validity of the model and the algorithm is verified by simulation experiments,which take the Port of Qingdao as an example and the performance under different conflicting resolution strategies is compared.The results show that,for the given task,the proposed solution to conflict-free path and the schedule provided by the algorithm can complete the task with minimum energy consumption without loss of AGVs utilization,and the number of AGV-mates should be adjusted according to the task rather than keeping unchanged.Comparison results indicate that our proposed approach could efficiently find solutions within 6%optimality gaps.Energy consumption is dropped by an average of 15%.
基金the Innovation Action Project from Science and Technology Commission of Shanghai Municipality (No. 08170511300)
文摘The throughput capacity of a container terminal is very important in planning and designing at container terminals.The existing methods estimated the throughput capacity without considering its change resulting from the different combination patterns of the types of arriving vessels.A simulation model is established to estimate the throughput capacities of a container terminal under different combination patterns of the types of arriving vessels.It shows that the throughput capacity of a container terminal is influenced by the utilization rates of the berth and quay cranes which result from the different combination patterns of the types of the arriving vessels.It provides a practical approach to estimate the throughput capacity of a container terminal considering the types of the vessels,and it is also helpful for the decision makers to raise the throughputs of the container terminals by optimizing the combination patterns of the types of arriving vessels.
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The freight logistics includes all the processes needed to supply industry,retailers and wholesalers and final customers with goods.Such processes generate a flow of goods that,in the global supply chain,mainly relies on the activities carried out within worldwide container terminals.In this paper,the authors present a simulation model of a real container terminal.After some preliminary analyses,the simulation model is first used with Design of Experiments and Analysis of Variance to investigate the effects of different resources allocations(i.e.,number of forklifts and tractors)and some parameters(i.e.,inter-arrival times,container unloading time)on the container terminal performances in terms of total number of handled containers per day.Then,based on the results achieved through the Design of Experiments and Analysis of Variance,the simulation model is used with genetic algorithms to carry out a range allocation optimization on berth assignment to incoming ships and number of tractors serving each quay crane.The aim of the optimization is the minimization of the average time spent by each ship in the port area(decreasing,as consequence,costs and increasing service level provided to final customers).
文摘An integrated model is presented to schedule the container handling system. The objective is to improve the coop- eration between different types of equipments, and to increase the productivity of the terminal. The problem is formulated as a Hybrid Flow Shop Scheduling problem with precedence constraint, setup times and blocking (HFSS-B). A tabu search algorithm is proposed to solve this problem. The quality and efficiency of the proposed algorithm is analyzed from the computational point of view.
基金the Agency for Science, Technology and Research, the Maritime and Port Authority,and Nanyang Technological University, Singapore
文摘In this paper, we apply the split-platform automated storage/retrieval systems (SP-AS/RSs) (Hu et al., 2005) to store containers in the yard to improve the yard performance and to increase the utilization of the yard space. The layout of an SP-AS/RS based yard is described in detail. To achieve an efficient operation, we present a novel yard space allocation policy called the ‘second-carrier-based allocation policy’, which can help to alleviate the out-of-sequence problem of containers and the congestion of vehicles at the AS/RS racks. Different allocation policies are compared by an integrated container terminal simulation system. The simulation results show that the second-carrier-based policy is very efficient and has the potential to offer high terminal performance.
基金Supported by the National Natural Science Foundation of China(No.71502129,61473211)
文摘The integrated berth-crane allocation problem at container terminals is addressed under the uncertainty of vessel arrival time at operational level. To ensure both robustness and flexibility of the 2-stage decision processes,a dynamic decision framework is proposed based on the dynamic analysis of information and operation at container terminal. A mixed integer programming model is established aiming at minimizing total cost of all vessels,including the cost of fixed to-be-executed decisions in the 1^(st) stage and expected cost of the adjustable stochastic-scenario-based decisions of all scenarios in the 2^(nd) stage. A multi-layer nested Tabu search is proposed for each epoch dynamically. Finally numerical experiments have been conducted to testify the effectiveness and efficiency of the proposed model and algorithm.
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.