• Journal of Korea Port Economic Association
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• v.26 no.3
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• pp.42-55
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• 2010

This paper primarily deals with a decision-making for determining the number of voyages in each ship size under a specific port structure in order to minimize the total transport cost consisting of transport cost at sea, queuing cost in port, and inventory cost in yard. As a result of computer simulation using queuing model characterized by inter-arrival time distribution, we were able to find out some combination of voyage numbers of 3 ship-size(50,000-ton, 100,000-ton, and 200,000-ton), where the total transport cost can be minimized under a specific port structure. The simulation model also allows us to figure out any trade-off relationship among sea transport cost, queuing cost in port, and inventory cost in yard. Put it differently, an attempt to reduce the sea transport cost by increasing the number of voyages of the largest ship size, the transport cost incurred in both port and yard is hypothesized to be increased and vice versa. Consequently, Port managers are required to adjust the number of annual number of voyages allocated in each ship size, put into the sea lines for importing raw materials, in order to optimize the transport costs incurred under the specific port system. We may consider a net present value(NPV) model for performing an economic feasibility analysis on port investment project. If a total discounted net benefit, including cost savings, exceeds the initial investment for an additional berth construction, then we accept the port investment project. Otherwise, we reject the proposed port investment plan.

• Journal of Korea Port Economic Association
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• v.29 no.3
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• pp.159-174
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• 2013

This paper mainly deals with the appropriation of ship voyage allocation, using a heuristic regression model, in order to reduce total costs incurred in port, yard and at sea under the specific port condition. Because of different behavior of costs incurred in port, yard and at sea, an effort to minimize these costs by adjusting the number of voyages for three ship classes(50,000, 100,000, and 150,000-ton) should be made. For instance, if the port managers attempt to reduce the sea transport cost by increasing the annual allocated number of ship voyages classed 150,000-ton for economies of scale, they have no choice but to suffer a significant increase in queueing cost due to port congestion. To put it differently, there are trade-off relationships among the costs incurred in port, yard, and at sea. We utilized a computer simulation result to perform a couple of regression analyses in order to figure out the appropriate range of allocated number of voyages of each ship class using a heuristic approach. The detailed analytical results will be shown at the main paper. We also suggested a net present value(NPV) model to make a proper investment decision for an additional berth of 200,000-ton class that alleviates port congestion and reduces transport cost incurred both in port and at sea.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.11a
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• pp.159-167
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• 2000

During the operation of crane system in the container yard, it is necessary to control the crane trolley position so that the swing of the hanging container is minimized. Recently an automatic control system with high speed and rapid transportation is required. Therefore, we designed a controller to control the crane system with disturbances and weight change. In this paper, we present the neural network two degree of freedom PID controller to control the swing motion and trolley position. Then we executed the computer simulation to verify the performance of the proposed controller and compared the performance of the neural network PID controller with our proposed controller in terms of the rope swing and the precision of position control. Computer simulation results show that the proposed controller has better performances than neural network PID with disturbances.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.142-142
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• 2000

During the operation of crane system in container yard, it is necessary to control the crane trolley position so that the swing of the hanging container is minimized. Recently an automatic control system with high speed and rapid transportation is required. Therefore, we designed a controller to control the crane system with disturbances. In this paper, Ive present the neural network two degree of freedom PID controller to control the swing motion and trolley position. Then we executed the computer simulation to verify the performance of the proposed controller and compared the performance of the neural network PID controller with our proposed controller in terms of the rope swing and the precision of position control . Computer simulation results show that the proposed controller has better performances than neural network PID with disturbances.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.11
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• pp.2313-2320
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• 2011

The management of a panel block shop in a shipyard is a complex process that entails the largest amount of work and in which many decisions are involved. Shipbuilders have considered the process as a bottleneck since every panel for every ship and offshore hull structure must be processed through the shop. In order to maximize process productivity, simulation-based ship production execution system(SPEXS) is proposed for panel block operations utilising discrete-event simulation and simulated annealing. An application of panel block assembly shop, called SPEX-Panel supports production planners by general dispatching rules and metaheuristics to make better scheduling decisions on the shop floor. In addition, the system will help increase productivity in the yard with continuous improvement.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.203-208
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• 2004

The objective of this study is to analyze the efficiency of marshalling work using ATC(automated transfer crane) for ACT(automated container terminal). It is important fact to assignment of containers, because the character of ACT which block layout is vertical for berth and there are four other works which are inbound, oubound, loading and unloading in one block. And then there is need which assignment of containers with remarshaling work using ATCs in one block. Therefore, we analyze the efficiency of remarshaling work using simulation and suggest the assignment methodology of containers in yard

• Journal of Navigation and Port Research
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• v.33 no.5
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• pp.331-337
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• 2009

Container crane is main equipment in container terminals and it determines the productivity and the efficiency of container terminals. The typical type of container cranes has the single trolley and one among advanced types of them has the dual trolley. The objective of this paper is to analyze the buffer size of a container crane with the dual trolley in container terminals. We present a simulation model for analysing the buffer space of a container crane with the dual trolley. The buffer space is located between main trolley in sea-side and second trolley in yard-side. We performs various simulation experiments and analyze the buffer size to estimate the required productivity.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.42-43
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• 2019

In-situ production of PC (precast concrete) members can reduce costs by about 14.5% -21.6% compared to in-plant production due to the reduction of transportation costs, factory profits and overhead costs. However, in-situ production of PC members presents a variety of risks, including member production and yard area securing, and lead time for production within the installation period. To solve this, it is necessary be able to analyze and control and monitor the risk factors that influence in-situ production for PC member. The purpose of this study is to develop a dynamic simulation model for in-situ production and erection integrated management for PC members. For this study, risk factor identification, causal loop diagram, and dynamic simulation model construction were performed sequentially. The results of this study will be used as a basis for developing a risk management model for PC in-situ production.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.359-367
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• 2005

In order to increase the productivity of container terminals, automation is being considered seriously in nowadays. A yard is usually automated by running autumated RMGs (rail mounted gantries) which may require somewhat a different stacking strategy to archive a better performance. In this paper, we present a simulation model for RMGs and summarize experimental results with two different stacking strategies applied to a horizontal block which has two non-crossable RMGs. The concentrating strategy, which stacks containers belong to a single ship together and dedicateds each RMG to either ship services or external truck services, showed a good performance in ship unloading. In the contrast, the distributing strategy, which partitions a block into two regions and binds each RMG to one of the regions to improve the productivity of ship services by running each RMG alternately, is suggested for blocks of exporting.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.273-280
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• 2004

Intra-block remarshalling is the task of rearranging into some target bays those containers whim are scattered around the block, so that the containers can be loaded onto the ship ffficiently. Howeuer, if we rearrange the containers without considering the container larding sequence, too mud! rehandling work will be required at the time rf larding to fetch the right containers whim are stacked under the wrong ones. Therefore, the remarshalling should be done by moving the relevant containers in an appropriate order. This paper presents an efficient heuristic search technique for finding an appropriate container moving order during remarshalling to avoid rehandling at the time of larding. Simulation experiments have shown that the proposed method can generate rehandling-free solutions in a real time.