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Container terminal yards are automated terminal yards. The rail-mounted gantry crane (RMGC) and rail-mounted gantry crane tracks (RMGCTs) that frequently operate in terminal yards need to be inspected regularly to ensure the safe operation of container transportation in the yard. This paper proposes a framework for the path planning of RMGCT visual inspection using a UAV in container terminal yards in a port environment. The framework consisted of two main aspects. First, a global path to all inspection viewpoints was planned according to the inspection requirements using the A* algorithm and the improved minimum snap method. Second, the intelligent bidirectional rapidly exploring random trees star (IB-RRT*) algorithm was introduced to plan the local path during the flight of the UAV. Finally, the feasibility of the path-planning framework was demonstrated using simulation experiments. [ABSTRACT FROM AUTHOR]

The port container gantry crane studied in this paper is a four-degree-of-freedom spatial continuous system. In actual work, in order to make the container transfer smoothly, the response of the whole system needs to be accurately predicted and timely adjusted. The whole system is divided into rotary mechanism, lifting mechanism, lifting trolley mechanism, and big cart mechanism for detailed analysis. By constructing the field transfer matrix, a one-dimensional wave equation of continuous system and the Lagrange equation with redundant parameters, the response of each subsystem is solved precisely. The results of the study found that in some periods, the swing of the container was too large. In order to improve the safety and stability of transmission, an active control method of specific point in time excitation (SPE) is proposed for the first time. This method predicts the swing amplitude of the container in advance using the response results of the numerical model. When the set response interval is exceeded, the external excitation intervention can effectively inhibit the moving range of the container in the transit process. Finally, the results are compared with the simulation model to achieve the experimental purpose. It is in line with the expected experimental effect. [ABSTRACT FROM AUTHOR]

Due to their unique structural design, portal cranes have been extensively utilized in bulk cargo and container terminals. The bearing fault of their drive motors is a critical issue that significantly impacts their operational efficiency. Moreover, the problem of imbalanced fault samples has a more pronounced influence on the application of novel fault diagnosis methods. To address this, the paper presents a new method called bidirectional gated recurrent domain adversarial transfer learning (BRDATL), specifically designed for imbalanced samples from portal cranes' drive motor bearings. Initially, a bidirectional gated recurrent unit (Bi-GRU) is used as a feature extractor within the network to comprehensively extract features from both source and target domains. Building on this, a new Correlation Maximum Mean Discrepancy (CAMMD) method, integrating both Correlation Alignment (CORAL) and Maximum Mean Discrepancy (MMD), is proposed to guide the feature generator in providing domain-invariant features. Considering the real-time data characteristics of portal crane drive motor bearings, we adjusted the CWRU and XJTU-SY bearing datasets and conducted comparative experiments. The experimental results show that the accuracy of the proposed method is up to 99.5%, which is obviously higher than other methods. The presented fault diagnosis model provides a practical and theoretical framework for diagnosing faults in portal cranes' field operation environments. [ABSTRACT FROM AUTHOR]

The heavy congestion at the global ports and the impact of the pandemic spread make the automated container terminal competitive. With the operations of more and more automated container terminals, the optimization of yard space allocation becomes one of the most urgent issues for improving the handling efficiency for the automated container terminal. To figure out the optimal clustering strategy to allocate the containers in the automated container terminal, this study investigates the stacks allocation with different scenarios. A novel stack-based allocation model is built to balance both the transportation distance and the allocation dispersion among blocks. Based on the model we built, we talked about the impact of efficiency of automated rail-mounted gantry crane and the berthing time for each vessel on the stacks allocation. The results show that the stack-based allocation with multi-batches in the same bay is suitable for the automated container terminal, while both the efficiency of the automated rail-mounted gantry crane and the berthing time will directly affect the total transportation distance for allocating the containers. The research is very inspiring for the terminal manager to choose the suitable clustering strategy and improve the yard space management for the automated container terminal. [ABSTRACT FROM AUTHOR]

A sea-rail automated container terminal (SRACT) plays a crucial role in the global logistics network, combining the benefits of sea and railway transportation. However, addressing the challenges of multi-equipment cooperative scheduling in terminal and railway operation areas is essential to ensure efficient container transportation. For the first time, this study addresses the cooperative scheduling challenges among railway gantry cranes, yard cranes, and automated guided vehicles (AGVs) under the loading and unloading mode in SRACTs, ensuring efficient container transportation. This requires the development of a practical scheduling model and algorithm. In this study, a mixed integer programming model was established for the first time to study the multi-equipment cooperative scheduling problem of a SRACT under the loading and unloading mode. A self-adaptive chaotic genetic algorithm was designed to solve the model, and the practicability and effectiveness of the model and algorithm were verified by simulation experiments. Furthermore, this study also proposes an AGV number adjustment strategy to accommodate changes in vessel arrival delays and train container types. Simulation experiments demonstrated that this strategy significantly reduces loading and unloading time, decreases equipment energy consumption, and improves the utilization rate of AGVs. This research provides valuable guidance for ongoing SRACT projects and advances and methodological approaches in multi-equipment co-operative scheduling for such terminals. [ABSTRACT FROM AUTHOR]

It is an important engineering safety problem to control the swing of the suspended objects of container gantry crane. As an important construction machinery for logistics transportation and handling, it is widely used in port container yards. However, due to the flexible characteristics of the wire rope and the heavy working level of the crane container, there will be a large swing during the transportation process, resulting in cargo collision and uncertain load, resulting in cargo damage and casualties. In this paper, a dynamic model of container gantry crane is established according to Lagrange dynamics equation and the controllability of the system is verified. A hierarchical sliding mode controller (HSMC) is designed, and its stability is proved by using Lyapunov theory and Barbalat's lemma. The simulation results show that the controller has high displacement tracking accuracy, can suppress the container swing Angle and attitude pitch Angle in a short time and has strong robustness and stability for the variable system with different parameters. In addition, a platform is built to verify the reliability of the method. [ABSTRACT FROM AUTHOR]

This paper is concerned with unloading of containers at ports, which are key to international trade. Work on the gantry cranes takes place 50 m above ground level in an operation room with a glass footwell, which causes to arise a psychological bias. We conducted a line-of-sight measurement of gantry crane operators working in such an environment. Based on this data, cognitive bias was defined by our own, and certain characteristics could be found by visualizing the relationship with years of experience. We discuss how this can be used for skill transfer [ABSTRACT FROM AUTHOR]

A new layout of the U-shaped automated terminal is more convenient to connect between the terminal and the railway. In this study, a sort of cluster scheduling method for multiple equipment between a U-shaped automated terminal yard and a railway yard is proposed. The innovation points are as follows: (1) Considering that the rail gantry crane (RGC), intelligent guided vehicle (IGV), and double cantilever rail crane (DCRC) usually work in groups, they are grouped and cluster-scheduled. (2) A hybrid integer programming model is established to minimize container transit times, and non-crossing constraints and safe distance constraints are included to reflect complex interactions among terminal equipment. (3) An ADMM (Alternating Direction Method of Multipliers)-based framework is proposed to dualize the hard-edge constraints and break the cluster scheduling problem down into a specific subproblem set of RGCs, IGVs, and DCRCs, and their time cost is iteratively adjusted to improve the solution quality. The experiment results show that the solution of the proposed method, which can effectively avoid IGV conflict, is better than that of the standard Lagrange relaxation (LR) when the number of equipments participating in scheduling increases. This study on multi-equipment cluster scheduling is conducive to improving the collaborative handling and continuous work of terminal equipment, and improving the efficiency of the automated terminal and the sea–rail intermodal transport. [ABSTRACT FROM AUTHOR]

Container terminals play an essential role in the current global supply chain, and their efficiency influences businesses throughout the supply chain. One of the most critical decisions in the operation of container terminals is the number of deployed rubber tyred gantry (RTG) cranes to handle the containers. The RTG crane is the main equipment that handles containers in the stacking area of many container terminals worldwide. Every shift, container terminal operators decide how many RTG cranes are needed to stack and retrieve containers. This decision, if made optimally, can significantly improve the daily throughput of terminals and dramatically reduce port congestion. This article aims to determine the optimal number of RTG cranes in a container terminal by formulating the problem as a mixed-integer linear program. Our proposed formulation can find optimal solutions efficiently, usually in less than a second. The results show that the workload, storage capacity, and shift duration significantly influence the optimal number of RTG cranes. [ABSTRACT FROM AUTHOR]

Green container terminals have gained much attention to satisfy the demand for sustainable and environmentally friendly transport. As one of the major polluters in container terminals, rubber-tyred gantry cranes have already been widely replaced by electric rubber-tyred gantry cranes (ERTGs). This article exploits the features of ERTGs and studies the ERTG scheduling problem in container terminal yards considering the carbon dioxide emissions and task delays simultaneously. The problem is converted into a selective vehicle routing problem with soft time windows (SVRPSTW) and formulated as a mixed integer linear programming model. A column generation algorithm embedded in a branch-and-bound framework is employed to solve the problem. A hybrid acceleration strategy combining the label-setting algorithm with a tabu search algorithm is proposed. Finally, the proposed method is validated via computational experiments. The proposed method provides an efficient tool for carbon-efficient scheduling of ERTGs and thus contributes to the development of green ports. [ABSTRACT FROM AUTHOR]

• Little is known about energy consumption of twin RMG systems with handshake area(s). • An agent-based simulation is built to estimate energy consumption under uncertainty. • Stochastic arrivals and dynamic interactions among equipment are considered. • Optimal energy reduction strategy varies with changing work conditions. • Optimal strategy is made by trade-off between the efficiency and energy consumption. This study investigates the effects of twin rail-mounted gantry crane (RMG) scheduling strategies and handshake area designs on container yard efficiency and energy consumption. A handshake area is set for temporary storage of containers within each block, enabling the cooperation and interference avoidance of twin RMGs. Considering the complexity and dynamics, we establish a simulation model for the twin RMG operations with agent-based and discrete event simulation modeling. Container relocation, microscopic movements of RMGs, and stochastic arrivals of automated guided vehicles (AGVs) and external trucks (ETs) are simulated, and the corresponding efficiency and energy consumption are quantitatively estimated. By testing the six RMG scheduling strategies and thirteen handshake area designs, the results show that the 2-OPT RMG scheduling strategy (an optimization heuristic that attempts to find the schedule with the minimum makespan) outperforms the other strategies in terms of efficiency. However, the optimal RMG strategy for minimal energy consumption depends on the ratio of landside and seaside requests and handshake area settings. Furthermore, the location of the handshake area significantly affects the efficiency and power consumption of AGVs and RMGs. This study can provide decision support to improve the efficiency and reduce energy consumption of the twin RMGs by selecting a specified combination of the RMG scheduling strategy and the handshake area design. [ABSTRACT FROM AUTHOR]

With the growth of ocean transport and with increasing vessel sizes, managing congestion at the landside of container terminals has become a major challenge. The landside of a sea terminal handles containers that arrive or depart via train or truck. Large sea terminals have to handle thousands of trucks and dozens of trains per day. As trains run on fixed schedule, their containers are prioritized in stacking and internal transport handling. This has consequences for the service of external trucks, which might be subject to delays. We analyze the impact of prioritization on such delays using a stochastic stylized semi-open queuing network model with bulk arrivals (of containers on trains), shared stack crane resources, and multi-class containers. We use the theory of regenerative processes and Markov chain analysis to analyze the network. The proposed network solution algorithm works for large-scale systems and yields sufficiently accurate estimates for performance measurement. The model can capture priority service for containers at the shared stack cranes, while preserving strict handling priorities. The model is used to explore the choice of different internal transport vehicles (with coupled versus decoupled operations at the stack and train gantry cranes) to understand the effect on delays. Our results show that decoupled transport vehicles in comparison to coupled vehicles can mitigate the external truck container handling delays at shared stack cranes by a large extent (up to 12%). However, decoupled vehicles marginally increase the train container handling delays at shared stack cranes (up to 6%). When train arrival rates are low, prioritizing the handling of train containers at the stack cranes significantly reduces their delays. Further, such prioritization hardly delays external truck containers. • Model the interactions among train and external truck containers at shared cranes. • Model synchronization of train bulk arrival containers with transport vehicles. • Model the service priority of train container over external truck container. • Decoupled vehicles decrease external truck waiting time at shared cranes. • Decoupled vehicles slightly increase train container waiting time at shared cranes. [ABSTRACT FROM AUTHOR]

As a critical node of the global transportation network, ports have great potential in promoting transportation emission reduction. Promoting the low-carbon transition of ports by using clean energy is effective. Using hydrogen energy in automated container terminals (ACTs) has become popular in port emission-reduction research. The research object is the main port equipment—the automated rail-mounted container gantry crane (ARMG). This research designs a staged investment decision-making scheme for ARMGs' hydrogen energy transition. The Internet of Things (IoT) architecture in ACTs collects ARMG equipment operation and carbon emission data. It provides a basis for data acquisition in ARMGs' hydrogen energy transition. Furthermore, ports can adopt big data technology to analyze the correlation between equipment operation and carbon emissions. Finally, the digital twin platform will visualize the ARMG equipment operation and carbon emission behavior to remote operators. These advanced technologies can achieve status monitoring and simulation prediction, which will support ARMGs' hydrogen energy transition. However, the ARMGs' hydrogen energy transition has a long cycle, large investment, and strong variability. Ports should make staged investment decisions based on the digital twin platform's status monitoring and simulation prediction analysis results. Therefore, this research establishes an optimization model for ARMGs' low-carbon transition investment decision based on the real options method, and analyzes the staged investment scale and timing of ARMGs' hydrogen energy transition. The results provide a popularized decision-making scheme for the low-carbon transition of ports' equipment, which could facilitate the low-carbon transition of ports' equipment. [ABSTRACT FROM AUTHOR]

Rubber tire container gantry cranes (RTG) are the most commonly used equipments to stack containers in ports. With four sets of ropes hoisting the cargo, the system dynamics become much more complicated and unpredictable when compared with traditional gantry cranes, which imposes higher requirements to the skills of operators. During the delivering process, large sway motion of the container is often excited by inappropriate manual operations, which badly impairs efficiency and safety. This issue is made even worse when considering the elasticity of rubber tire, wind disturbances, and many other practical disturbances. To improve the working efficiency of ports, an automatic antiswing trajectory planning method is proposed for RTG in this article. Specifically, reference trajectories are first generated to ensure that the trolley/rope accurately reach the desired position. After that, appropriate feedback terms are incorporated to online optimize the trajectories, so that the container swing motion is sufficiently suppressed even under unfavorable conditions. Lyapunov-based analysis is presented to guarantee the correctness of our conclusion. Furthermore, extensive hardware experiments on a practical RTG are performed to demonstrate the efficiency of the proposed method. To our best knowledge, with concise structure and superior antiswing ability, the proposed method is one of the very few methods which can be successfully applied to the practical RTG systems. [ABSTRACT FROM AUTHOR]

The paper presents an Integrated Maintenance Decision Making Model (IMDMM) concept for cranes under operation especially into the container type terminals. The target is to improve cranes operational efficiency through minimizing the risk of the Gantry Cranes Inefficiency (GCI) results based on the implementation of the Digital Twins concept for maintenance purposes. The proposed model makes a joint transportation process and crane maintenance scheduling, relevant to assure more robust performances in stochastic environments, as well as to assess and optimize performances at different levels, from components and transport device to production systems (container terminal). The crane operation risk is estimated with a sequential Markov chain Monte Carlo simulation model and the optimization model behind of IMDMM is supported through the Particle Swarm Optimization algorithms because the objective function a non-linear stochastics problem with bounded constrains. The developed model allows the container terminal operators (management process) to obtain a maintenance schedule that minimizes the GCI (holistic indicator), as well as establishing the desired level of risk. The paper demonstrates the effectiveness of the proposed maintenance decision making concept model for cranes under operation using data from of a real container terminal (case study). [ABSTRACT FROM AUTHOR]

Rail–road container terminals can be seen as buffers within a large logistics network encompassing hinterland distribution systems. They are used as temporary storage points for containers such that unloading operations from a train and loading operations onto a truck need not be synchronized. Container transferring operation implemented by gantry cranes is one of the most important issues to ensure efficient logistics. To enable efficient container transfer, this article considers the special features of container movement, and integrates the starting position and the ending position of container movement into the gantry crane scheduling problem. In order to solve the proposed problem, this article develops two models: first using mixed integer programming, and secondly using constraint programming (CP). Since the problem is computationally intractable for realistic sizes, this article also proposes a logic-based Benders decomposition (LBBD) methodology to solve it. This method exploits a natural decomposition of the studied problem into a relaxed master problem (RMP) solved by mixed integer programming (MIP), and a series of sub-problems, solved separately by MIP and CP. Computational experiments are performed on generated instances, the structures of which are designed to follow the practical application. The computational results show that the CP approach is better suited to solve the proposed problem with small-sized and medium-sized instances compared with MIP and LBBD. In addition, the LBBD framework is far superior to mixed integer programming on all but a few small instances, and it is highly effective in finding good-quality solutions for larger cases with up to 100 tasks within a reasonable runtime. Moreover, the results find that LBBD using constraint programming to solve the sub-problems usually outperforms LBBD with mixed integer programming on the instances tested. [ABSTRACT FROM AUTHOR]

With the development of the large ship, automated container terminals (ACTs) have serious energy consumption and carbon emission problems, reducing the loading and unloading time of ships can ease energy consumption, improve the working efficiency and service level of automated terminals. This paper studies the integrated scheduling problem of the gantry cranes (QCs), automated guided vehicles (AGVs) and automated rail-mounted gantry (ARMG) in automated terminal. According to the loading and unloading operation mode, we build the mixed integer programming model with the goal of minimizing the ship loading and unloading time, and through various algorithms of heuristic and hybrid improved to solve this problem, it proves the effectiveness of the model to obtain optimized scheduling scheme by numerical experiments, and comparing the different performance of algorithms, the results show that the hybrid GA-PSO algorithm with adaptive auto tuning is superior to other algorithms in terms of solution time and quality, which can effectively solve the problem of integrated scheduling to save the energy of automated container terminal. [ABSTRACT FROM AUTHOR]

In order to increase the productivity of sea port container storage yards, a triple-crossover-stacking-crane setting can be deployed. Although this setting yields promising results, there is increasing risk of cranes interfering. Coping with interference is a key factor for exploiting the potential of triple-crossover-stacking-cranes to increase overall productivity. In this paper, we tackle the problem of finding an assignment of transport jobs to cranes, a processing sequence for each crane as well as a conflict-free routing under the objective of minimizing the makespan. We develop several variants of branch-and-bound algorithms differing in the order of assignment and sequencing decisions and in the techniques applied for routing decisions. We compare the performance of our algorithms with regard to solution quality and run times and use standard solver CPLEX as benchmark. [ABSTRACT FROM AUTHOR]

Zheng, S. and Sha, J., 2020. Path optimum algorithm for container-integrated scheduling under dynamic mode in port terminals worldwide. Journal of Coastal Research, 36(4), 885–895. Coconut Creek (Florida), ISSN 0749-0208. Optimizing container-integrated scheduling under dynamic mode in container ports worldwide is important during the transition of container terminals from traditional to automated management, which includes their transformation and upgrade, and it is important for the improvement of yard efficiency. Given the approach sequence and departure sequence of containers, with the objective of minimizing the number of container relocations in the process of container location selection, this problem can be described as a nondeterministic polynomial hard (NP-hard) problem. In order to obtain practical and instructive conclusions, this paper investigates both the approach and the departure problems of containers. On this basis, the simultaneous approach and departure of containers a re considered in dynamic mode, and a path optimum algorithm (POA) of container-integrated scheduling is proposed. This algorithm considers the different influences of the priority of containers, the movement of obstructive containers, and the Manhattan distance of gantry cranes on the model; moreover, it sets the promotion of container yard overall efficiency as the ultimate goal and analyzes the operation process from a more practical standpoint, in line with real-life production. Finally, this paper proposes a generic strategy for container-integrated scheduling, which provides a theoretical basis for container port operators worldwide to allocate and optimize port resources, and provides concrete guidance for operation rules. [ABSTRACT FROM AUTHOR]

Due to the considerable growth in worldwide container transportation, the configurations of facility and operating processes need to be optimized in container terminals. This paper studies a novel scheduling problem for twin automated gantry cranes with a handshake area encountered in railroad container terminals. The handshake area is a temporary storage place where one gantry crane drops a container there for another crane to complete the movement. A limited random search method is designed to produce the operation sequence of cranes. Four interference-handling rules and four combined sequence rules are proposed to obtain the movement scheme of twin cranes based on First Come First Serve strategy. Computational experiments are implemented to investigate the performance of these rules. The results show the combined sequence rules outperform the interference-handling rules, and the best rule is C2-OH. For the C2-OH rule, the priority of handling tasks is assigned to right-side crane and splitting-tasks are handled first. When twin cranes request to enter the handshake area simultaneously, right-side crane must leave without load immediately after unloading. Meanwhile, the twin cranes always choose the nearest task to handle until all have been completed. The runtime of C2-OH rule is very short and can be used to produce a schedule for real operations. [ABSTRACT FROM AUTHOR]

In order to improve the transshipment efficiency of transit containers in the port or the port-type railway network container freight station (PRNCS) with the condition that each transit container matches a railway flat-car, this paper studied the optimization of operation path of the rail mounted gantry crane (RMG) in the loading and unloading track for containers transshipped directly from highway to railway. Based on the basic model of TSP, the paper constructed the optimization model for the operation path of RMG, and designed the Ant Colony Algorithm (ACA) to solve it, and then obtained the operation scheme of RMG having the highest efficiency. Finally, the validity and correctness of the model and algorithm were verified by a case. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article discusses the challenges faced by South Africa's state logistics firm, Transnet, in dealing with a backlog at ports. The government has pledged to inject $2.5 billion into Transnet to help address the issue. Transnet, which operates the rail freight network and all ports in South Africa, has been plagued by operational, financial, and governance challenges, as well as debt. The delays at Durban port, which handles 60% of the country's container traffic, have had a significant impact on the economy. The article also briefly mentions the launch of the second phase of the Tema Port Expansion Project in Ghana and the upcoming opening of Rubavu port in Rwanda. [Extracted from the article]

With the development of automated container terminals (ACTs), reducing the loading and unloading time of operation and improving the working efficiency and service level have become the key point. Taking into account the actual operation mode of loading and unloading in ACTs, a mixed integer programming model is adopted in this study to minimize the loading and unloading time of ships, which can optimize the integrated scheduling of the gantry cranes (QCs), automated guided vehicles (AGVs), and automated rail-mounted gantries (ARMGs) in automated terminals. Various basic metaheuristic and improved hybrid algorithms were developed to optimize the model, proving the effectiveness of the model to obtain an optimized scheduling scheme by numerical experiments and comparing the different performances of algorithms. The results show that the hybrid GA-PSO algorithm with adaptive autotuning approaches by fuzzy control is superior to other algorithms in terms of solution time and quality, which can effectively solve the problem of integrated scheduling of automated container terminals to improve efficiency. [ABSTRACT FROM AUTHOR]

In today's ports, the storage area is often the bottleneck in the serving of a vessel. It is therefore an important influencing factor in the minimization of the turnaround time of the vessels, which is the main objective in operational planning in container terminals. The operational planning of the yard cranes strongly impacts the yard's efficiency. This planning task comprises the assignment of jobs to cranes, the sequencing of jobs per crane and the scheduling of crane movement and job executions subject to time windows and precedence constraints. A common yard configuration is a block storage system with two identical automated gantry cranes, called twin cranes. These cranes are subject to non-crossing constraints and therefore often exclusively serve either the landside or the seaside of the terminal. A polynomial-time algorithm for the scheduling subproblem of the cranes is introduced. As the sequencing and assignment part of this planning task is NP-hard, the overall problem is solved heuristically with a branch and bound procedure that includes the introduced scheduling algorithm as an evaluation subroutine. A computational study is presented to test the performance of this approach against a mathematical program solved by CPLEX. [ABSTRACT FROM AUTHOR]

Zheng, S.; Sha, J., Wang, A., 2019. An improved storage-space selection model and algorithm for outbound shipping containers: Considering the synchronous operation of multiple gantry cranes in port terminals worldwide. Journal of Coastal Research, 35(5), 1120–1130. Coconut Creek (Florida), ISSN 0749-0208. Enhancing operation efficiency and strengthening core competence of storage yard are vital to exist and succeed for container ports worldwide. Aiming at improving container terminals' operational efficiency, this paper researches selecting locations for outbound containers and optimizing the relocation paths during retrieval operations. The outbound containers' storage-space selection problems (OCSSSP) can be concerned with emptying all the containers stacked in one block where every outbound container is given a fixed extractive sequence with the fewest number of relocations. The OCSSSP is a Non-Deterministic Polynomial Hard Problem. To increase the practical guiding significance of research conclusion, this paper further improves the model from synchronous operations of gantry cranes. The research content extends from one single piece of equipment to multiple pieces of equipment and conducts an in-depth study on the operation of a single piece of equipment, the independent operation of multiple pieces of equipment, and the collaborative operation of multiple pieces of equipment. Numerical experiment results show that the effect of the collaborative operation between different gantry cranes is best, and the container relocation number is least. Therefore, delimiting the joint operation areas between different gantry cranes makes the operation efficiency higher and the resources more reasonably utilized. This paper is consistent with the frontier to logistics development and satisfies the needs of developing technology and solving management problems in coastal container ports worldwide; therefore, this research has meritorious theoretical perceptiveness and considerable economic practicability. [ABSTRACT FROM AUTHOR]

The railway handling area of the railway container terminal is the main place for container sea–rail transportation. To enhance the efficiency of the handling systems and improve the coordination of different types of equipment in railway handling area, an integrated scheduling model is developed, which integrates the scheduling of rail-mounted gantry cranes (GCs), inner trucks (ITs), and yard cranes (YCs). This model considers not only train loading and unloading simultaneously, but GC interference and safety margin, GC and YC travel time as well as buffer area. A multi-layer genetic algorithm (MLGA) is proposed to solve the problem. Eventually, comparison experiments are conducted, including the experiments on handling process between non-optimization and optimization, MLGA with and without the balanced operator and the performance of different numbers of ITs. These experiments validate that the model and algorithm is feasible and efficient in both equipment scheduling and allocation problem. [ABSTRACT FROM AUTHOR]

As the high technology is applied in port industry, several changes may occur resulting to a reduction of the number of labors. The focus of this research includes: 1) What qualifications are needed as an operator of Automated Rubber Tyred Gantry (ARTG)?; 2) What factors do affect the labor absorption for ARTG operators?; 3) What efforts do the management of Semarang Container Terminal need to perform in order to overcome the problems related to ARTG? Based on the analysis, several findings were found: 1) a qualification for the crane operator was urgently needed especially for the position of the crane operator of Automated Rubber Tyred Gantry Crane (ARTG) in Semarang Container Terminal. 2) the factor which probably affected the labor absorption for crane operators was technology procifiency and English proficiency; and 3) what the management need to do was the employment expansion opportunities by transferring the crane operators to other ports whose cranes are not equipped with the new system. Moreover, the influence of ARTG reduced the absorption of RTG operators. Based on the findings, it is suggested that the management of Semarang Container Terminal needs to be careful in establishing any policies to overcome the problems. Thus there would not be any violation regarding any laws and regulations. [ABSTRACT FROM AUTHOR]

In this paper, new automated container terminals equipped with Unilateral-cantilever Rail-Mounted Gantry Cranes (URMGC) are considered as the research object. In the scenario, the automated guided vehicles can go deep among the container blocks arranged perpendicularly to the shoreline, which completely changes the yard's operation mode and affects its operational efficiency. In addition, considering the shortage of storage space in the yard, a flexible space allocation strategy for these yards is studied, and a mixed integer quadratic programming model is established to minimize the horizontal transportation cost of containers. An improved particle swarm optimization algorithm is designed to compensate for the increased complexity of the proposed model. To accelerate the solution speed, the quantity and priority rules are developed to generate reasonable initial solutions, and two velocity updating strategies are adopted to accelerate convergence. Numerical experiments are conducted to validate effectiveness and efficiency of the proposed method, and comparisons with fixed space allocation strategy are presented. The results show that the strategy and solution adopted in this paper can reduce the driving distance of AGVs in such terminal configurations effectively and potentially increase the handling capacity of the yard. [ABSTRACT FROM AUTHOR]

• A novel crane scheduling problem with sidekick (CSP-S). • Two useful mathematical models catered for the CSP-S. • A column generation approach based on segment decomposition. • A multi-attribute labeling algorithm for segment generation. • Practical insights for algorithm comparison and system design. In a new container terminal design, the perpendicular block is equipped with a Rail Mounted Gantry crane (RMG) and a sidekick Ground Trolley (GT). The RMG can handle containers by itself, or utilize the sidekick GT for container delivery. Unlike the traditional crane scheduling problem (CSP), the makespan is not merely determined by the job sequence, but also affected by the GT allocation and the RMG-GT synchronization. This novel optimization problem is defined as the crane scheduling problem with sidekick (CSP-S). It can be formulated as a mixed integer programming model to explicitly determine the GT allocation and the handover points. When the choice of handover points is remodeled as an implicit decision, the CSP-S can be transformed into an arc-based surrogate model. Based on the solution patterns of the surrogate model, it is found that the RMG-GT working plan can be decomposed into smaller "segments". Each segment consists of two intertwined paths of the RMG and the GT respectively. A column generation approach is proposed, where the segments can be generated by a multi-attribute labeling algorithm based on the surrogate model. This solution approach can optimally solve the traditional CSP, and outperforms all benchmark methods under the CSP-S. This can be attributed to the multi-attribute labeling algorithm, which accurately controls the RMG-GT synchronization. Numerical experiments showed that the column generation approach could be well implemented under the rolling-horizon manner in practice. It improved the "Nearest Job" strategy and the TSP-based method by more than 10 % and 5 % respectively under the CSP-S. Experiments also revealed that the RMG-GT system would benefit from a faster GT, but the marginal contribution of the GT speed was gradually reducing. [ABSTRACT FROM AUTHOR]

The gantry crane scheduling and storage space allocation problem in the main containers yard of railway container terminal is studied. A mixed integer programming model which comprehensively considers the handling procedures, noncrossing constraints, the safety margin and traveling time of gantry cranes, and the storage modes in the main area is formulated. A metaheuristic named backtracking search algorithm (BSA) is then improved to solve this intractable problem. A series of computational experiments are carried out to evaluate the performance of the proposed algorithm under some randomly generated cases based on the practical operation conditions. The results show that the proposed algorithm can gain the near-optimal solutions within a reasonable computation time. [ABSTRACT FROM AUTHOR]

Ports are the key connection of sea and land transportation. The coordination of container collection and distribution directly affect the handling efficiency of port in the entire supply chain. The optimization of tasks appointment for external trucks is crucial to improving the efficiency of container collection and distribution. The layout of the interchange points of external trucks are streamlined in automated container terminals where external trucks are commonly affected by the seaside operations. The traditional methods of external trucks assignment are inadequately applicable. In this paper an optimization model for the tasks appointment of external trucks is established for the joint optimization of external truck appointment and automated rail mounted gantry crane (ARMG) scheduling in the yard. Multiple objectives are generated including the balance of appointment among periods of time and between blocks. In this model the capacity constraints of the loading operations of external truck and moving operations of ARMGs between the seaside and landside are comprehensively considered. The model is solved by CPLEX and verified through sensitivity analysis. Different task appointment modes and various scenarios are compared and suggestions for selecting an optimization strategy are proposed. The experimental results show that the task appointment solutions effectively prevent the queuing of trucks, and balance the ARMG handling in automated container terminals, and herein the port efficiency is enhanced and the satisfaction of the carriers is promoted accordingly. It is also suggested that terminal managers should consider yard operations, operation capacity and the length of appointment period when considering the optimization of a task appointment schedule. While keeping optimize the appointment modes according to the operational conditions to improve the balance between the seaside and landside operations and reduce the idle of the ARMGs. [ABSTRACT FROM AUTHOR]

This paper treats the crane scheduling in a container port where two cooperative gantry cranes (denoted as twin cranes) jointly store import containers arriving from the seaside in a storage yard. We aim to minimize the makespan while non-crossing constraints among cranes need to be considered and preemptive container moves are allowed, i.e., the seaside crane sets down a container in some intermediate position where the landside crane takes over and delivers the container to its final storage position in the yard. Elementary complexity proofs are provided and efficient heuristic solution procedures are introduced and tested. [ABSTRACT FROM AUTHOR]

The demand for container terminal yards is growing significantly faster than the supply of available land; therefore, containers are typically stacked high to better utilize the land space in container yards. However, in the process of container retrieval, non-productive reshuffling may be required to relocate the containers that are stacked on top of the target container. Container retrieval is directly related to the operational efficiency of terminals. Because the industry has become increasingly competitive, it has become critical to introduce a systematic approach to retrieving containers. In this study, we develop a heuristic that can generate feasible working plans for rail-mounted gantry cranes (RMGC) in container yards to minimize the number of container movements while taking the RMGC working time into consideration. The methodology takes into consideration the case that containers are grouped in terms of their retrieval order. Multi-lift RMGC models also are studied. Comprehensive numerical experiments reveal that the method runs faster than other methods published in the literature by several orders of magnitude; additionally, our method is able to solve instances larger than practical use. The number of movements approaches a theoretical lower bound, and the numerical results clearly demonstrate the tradeoff between the number of movements and the working time, and provide useful insights for yard planning. [ABSTRACT FROM AUTHOR]

The Blocks Relocation Problem consists in minimizing the number of movements performed by a gantry crane in order to retrieve a subset of containers placed into a bay of a container yard according to a predefined order. A study on the mathematical formulations proposed in the related literature reveals that they are not suitable for its solution due to their high computational burden. Moreover, in this paper we show that, in some cases, they do not guarantee the optimality of the obtained solutions. In this regard, several optimization methods based on the well-known A ∗ search framework are introduced to tackle the problem from an exact point of view. Using our A ∗ algorithm we have corrected the optimal objective function value of 17 solutions out of 45 instances considered by Caserta et al. (2012) [4]. In addition, this work presents a domain-specific knowledge-based heuristic algorithm to find high-quality solutions by means of short computational times. It is based on finding the most promising positions into the bay where to relocate those containers that are currently located on the next one to be retrieved, in such a way that, they do not require any additional relocation operation in the future. The computational tests indicate the higher effectiveness and efficiency of the suggested heuristic when solving real-world scenarios in comparison with the most competitive approaches from the literature. [ABSTRACT FROM AUTHOR]

The control method of rubber tyre gantry (RTG) spreader in Qingdao Port Container Terminal is logic board control, which has many shortcomings such as expensive spare parts and high faults. This paper designs a new control system using programmable logic controller (PLC) centralized control to replace the original logic board control. The new system mainly contains complete ELME spreader control scheme design, hardware selection and PLC control program development, Its field application shows that the system has characteristics of high efficiency, low running cost, easy maintenance. [ABSTRACT FROM AUTHOR]

The goal of this paper is to present and evaluate the latest trends in the cargo handling equipment (CHE) industry, aimed at mitigating the environmental impact of container terminal operations and contributing to the sustainability of ports. The most common machines for handling containers are described and dealt with separately, with a focus on electric CHE, usually referred to as zero emission' CHE. In a separate chapter, recommendations on methodologies suitable for investigation of the environmental footprint of CHE without on-site measuring are reviewed. The life cycle assessment (LCA) methodology as a tool for comparison of conventional and 'zero emission' technology is emphasised with examples. The conventional diesel rubber-tired gantry (RTG) crane and utility tractor rig (UTR) are compared with an electric RTG and UTR using an LCA approach. [ABSTRACT FROM AUTHOR]

This paper proposes heuristic-based and local-search-based real-time scheduling methods for twin rail-mounted gantry (RMG) cranes working in a block at an automated container terminal. The methods reschedule the cranes in real time for a given fixed-length look-ahead horizon whenever an RMG finishes a job. One difficulty with this problem is that sometimes additional rehandling of containers needs to be carried out in order to complete a requested job, especially when other containers are stacked on top of the target container. These rehandlings are the main cause of the delay of the crane operations, leading to extended waiting of automated guided vehicles (AGVs) or external trucks that co-work with the cranes. By treating the rehandling operations as independent jobs in our solution methods, we can greatly facilitate the cooperation between the two RMGs. Through this cooperation, the workload of the two RMGs can be better balanced and interference can be more easily avoided, thereby maximizing crane utilization. Simulation experiments show that the waiting times of AGVs and external trucks are significantly reduced due to the increased utilization through cooperation. [ABSTRACT FROM AUTHOR]

We describe an approach for scheduling triple cross-over stacking cranes in an automated container storage block with asynchronous hand over at the transfer areas at both block front ends. The problem is characterised by frequent long crane moves that make job assignment and crane routing particularly challenging, as an intricate synchronisation between the cranes is required. The main objective is to maximise the productivity of the crane system under peak load while preventing delays in the transport of import and export containers from and to the transfer areas. Our method solves an online optimisation problem by constructing a new crane schedule for a certain planning horizon whenever a new job arrives or a job is completed. We report on extensive simulation studies for evaluating the scheduling strategy. The results show that the method performs significantly better than commonly used heuristics, leading to a productivity gain of more than 20%. [ABSTRACT FROM AUTHOR]