• Journal of Institute of Control, Robotics and Systems
• /
• v.22 no.6
• /
• pp.445-452
• /
• 2016

This paper discusses the dynamics and control problem of an overhead shuttle system (OSS), which is a critical part of the automated container terminal at a port. The main purpose of the OSS is efficient automated transport function of containers, which also requires high precision and safety. A major difference between the OSS and the conventional container crane is the configuration of the cables for hoisting the spreader. A mathematical model of the OSS is developed here for the first time, which results in an eight-pole system. Also, open loop control methods (trapezoidal and notch-type velocity profiles) are investigated so that the command input to the overhead shuttle produces the minimum possible sway of the payload. Simulation results show that the vibration suppression capability of the OSS is superior to the conventional overhead container crane, which is partially due to the cable configuration.

• Journal of Korean Society of Transportation
• /
• v.23 no.2
• /
• pp.51-60
• /
• 2005

Rail-road intermodal freight transport is a transoortation system that rail and road transport are utilized between origins and destinations. The roles of road(truck) in rail-road intermodal freight transport are pick-up and delivery that are keys parts of total transportation process. The objective of this study is to develop and evaluate the pick-up and delivery strategies for container trucks in order to increase their productivity. Two different strategies are developed : One is aimed for minimizing the total traveling distance of container and the other is to reduce the waiting time at client site. The comparative studies are performed on the actual network of Paris metropolitan. The simulation analysis shows that the proposed strategies are quite efficient in various performance measures.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.10a
• /
• pp.720-725
• /
• 1997

This paper is to study the wind effect of the large scale gantry crane. It is used to control the sway of gantry crane in the loadingiunloading job of containers. I'hls is very important in the automated container terminal because the sway of handling equipments in pard is caused by thc l~nexpected disturbance such as wind and dynamic inertia by deriving force. This study shows the process of the modelling simulation of the wind effect of the sway motion of the gantry crane. Pro-Engineer, ANSYS and DAD'; ~ rr . used for 3D solid modelling and dynamic simulation. Though this study did not use the real parameters. the ; cwl ~ shows the trend of the wind effect is very large in the large scale crane and should be considered in design of the large scale gantry crane. In future, if the study is done by using the real parameters, the result is much more ~ise!'ul for dynamic control and design of gantry crane.

• Journal of Intelligence and Information Systems
• /
• v.11 no.3
• /
• pp.25-43
• /
• 2005

In modern automated container terminals, automated guided vehicle (AGV) systems are considered a viable option for the horizontal tansportation of containers between the stacking yard and the quayside cranes. AGVs in a container terminal move rather freely and do not follow fixed guide paths. For an efficient operation of such AGVs, however, a sophisticated traffic management system is required. Although the flexible routing scheme allows us to find the shortest possible routes for each of the AGVs, it may incur many coincidental encounters and path intersections of the AGVs, leading to collisions or deadlocks. However, the computational cost of perfect prediction and avoidance of deadlocks is prohibitively expensive for a real time application. In this paper, we propose a traffic control method that predicts and avoids some simple, but at the same time the most frequently occurring, cases of deadlocks between two AGVs. More complicated deadlock situations are not predicted ahead of time but detected and resolved after they occur. Our method is computationally cheap and readily applicable to real time applications. The efficiency and effectiveness of our proposed methods have been validated by simulation.

• Journal of Intelligence and Information Systems
• /
• v.14 no.4
• /
• pp.103-116
• /
• 2008

This paper proposes quay crane (QC) scheduling algorithms that determine the working sequence of QCs over ship bays in a container vessel in automated container terminals. We propose two scheduling algorithms that examine the distribution of export containers in the stacking yard and determine the sequence of ship bays to balance the workload distribution among the yard blocks. One of the algorithms is a simple heuristic algorithm which dynamically selects the next ship bay based on the entropy of workloads among yard blocks whenever a QC finishes loading containers at a ship bay and the other uses genetic algorithm to search the optimal sequence of ship bays. To evaluate the fitness of each chromosome in the genetic algorithm, we have devised a method that is able to calculate an approximation of loading time of container vessels considering the workloads among yard blocks. Simulation experiments have been carried out to compare the efficiency of the proposed algorithms. The results show that our QC scheduling algorithms are efficient in reducing the turn-around time of container vessels.

• Journal of Navigation and Port Research
• /
• v.44 no.5
• /
• pp.382-391
• /
• 2020

In line with the trend of global transport volume which has increased rapidly over the years, internal transportation in seaports is always conducted with high frequency. Thus, there is always much potential for traffic jams as well as high transportation costs and emissions. Many efforts have been initiated to streamline the inter-terminal container transport (ITT) through the development of automated vehicles and equipment as well as using private transport facilities to overcome these limitations. The purpose of this paper to develop a framework to design, analyze, and validate the efficiency of a new ITT system in a port area based on the monorail network and automatic vehicles. First, the number of shuttles and loaders was determined depending on the transport demand scenario. Next, a simulation model was applied to evaluate the system performance as well as gain more insight into the working process of the ITT system. Finally, by setting goals for the performance indicators, the results showed that the system was highly efficient with 100% of the containers delivered to their destination on time. Besides, a series of other performance tracking was provided to provide insight into the system's capabilities.

• Journal of Navigation and Port Research
• /
• v.38 no.5
• /
• pp.493-501
• /
• 2014

An automated lifting vehicle(ALV) used in an automated container terminal is a type of unmanned vehicle that can self-lift a container as well as self-transport it to a destination. To operate a fleet of ALVs efficiently, one needs to be able to determine a minimum-time route to a given destination whenever an ALV is to start its transport job. To find a route free from any collision or deadlock, the occupation time of the ALV on each segment of the route should be carefully scheduled to avoid any such hazard. However, it is not easy because not only the travel times of ALVs are uncertain due to traffic condition but also the operation times of cranes en route are not predicted precisely. In this paper, we propose a routing method based on an ant colony optimization algorithm that takes into account these uncertainties. The result of simulation experiment shows that the proposed method can effectively find good routes under uncertainty.

• Journal of the Korea Society for Simulation
• /
• v.19 no.2
• /
• pp.29-41
• /
• 2010

Due to the recent technological advance, new types of AS/RS which can handle containers are being developed, and it is expected that they will be applied to related industries before long. Some companies and institutes in our country have constructed pilot systems for high-density-high-stacking systems and tested them to develop AS/RS-typed warehouses for containers. Along with this kind of construction efforts, development of rules to operate such systems efficiently and safely is also important. When outward-bound shipment is scheduled in container port, re-marshalling which rearranges containers in the yard to make shipment easy is conducted. In this paper, operating rules for the re-marshalling as well as simulation experiments to evaluate the performance of the rules are presented. We suggested two kinds of alternative sets of operating rules for re-marshalling and described the relevant logics corresponding to all possible cases for each alternative of operating rules. Through various simulation experiments, we found that each alternative has the merits and demerits at the same time and we could not say the one is always superior to the other. As a useful strategy, changing the applying operating rule is recommended from moment to moment depending on the expected number of operations at the landside input/output position.

• Journal of Navigation and Port Research
• /
• v.40 no.3
• /
• pp.113-120
• /
• 2016

If there are containers stacked upon the container to be fetched out of a container yard to vessel, rehandling which moves those containers to other places temporarily is needed. In order to avoid such rehandling, remarshalling which rearranges containers should be done before the vessel arrives. The remarshalling plan is commonly generated within a bay. It happens, however, that the generation of the intra-bay remarshalling plan within the permitted time is not possible because of bad stacking conditions. This paper presents the remarshalling algorithm which uses the empty slots of the neighboring bay as a temporary storage space. Simulation experiments have shown that the presented algorithm can generate the remarshalling plan within the permitted time under any staking conditions.

• Journal of Navigation and Port Research
• /
• v.40 no.6
• /
• pp.421-430
• /
• 2016

In this study, a gate simulation model was developed to reduce the truck waiting time for trucking companies servicing container terminals. To verify the developed model, 4 weeks of truck gate-in/gate-out data was collected in December 2014 at the Port of Busan New Port. Also, the existing gate system was compared to the proposed gate system using the developed simulation model. The result showed that based on East gate-in, a maximum number of 50 waiting trucks with a maximum waiting time of 120 minutes. With the proposed system the maximum number of waiting trucks was 10 with a maximum waiting time of 5.3 minutes. Based on West gate-in, the maximum number of waiting trucks was 17 and the maximum waiting time was 34 minutes in the existing gate system. With the proposed system the maximum number of waiting trucks was 10 with a maximum waiting time of 5.3 minutes. Based on West gate-out, the maximum number of waiting trucks was 11 with a maximum waiting time of 5.5 minutes. With the proposed system the maximum number of waiting trucks was 9 with a maximum waiting time of 4.4 minutes. This developed model shows how many waiting trucks there are, depending on the gate-in/gate-out time of each truck. This system can be used to find optimal gate system operating standards by assuming and adjusting the gate-in/gate-out time of each truck in different situations.