• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.2 s.29
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• pp.133-140
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• 2007

Since early times, captain have been sailing to select the optimum route considering the weather, ship loading status condition and operational scheduling empirically. However, it is rare to find digitalized onboard route support system whereas weather facsimile or wave and swell chart are utilized for the officer, based on captain's experience. In this paper, optimal route safety assessment system which is composed of voyage efficiency and safety component is introduced. Optimum route minimizea ETA(estimated time of arrival) and fuel consumption that shipping company and captain are requiring to evaluate for efficient voyage considering speed loss and power increase based on wave added resistance of ship. In the view point of safety, seakeeping prediction is performed based on 3 dimensional panel method. Finally, It is assistance measure for ship's optimum navigation route safety planning & assessment.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.6 no.2
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• pp.139-149
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• 1994

In this paper, a finite element technique is applied to the prediction of the wave resonance phenomena in harbors. The mild-slope equation is used with a partial reflection boundary condition introduced to model the energy dissipating effects on the solid boundary. For an efficient modeling of the radiation condition at infinity, a new infinite element is developed. The shape function of the infinite element is derived from the asymptotic behavior of the first kind of the Hankel's function in the analytical boundary series solutions. For the computational efficiency, the system matrices of the element are constructed by performing the relevant integrations in the infinite direction analytically. Comparisons with the results from experiments and other solution methods show that the present model gives fairly good results. Numerical experiments are also carried out to determine the proper distance to the infinite elements from the mouth of the halter, which directly affect the accuracy and efficiency of the solution.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.06a
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• pp.401-403
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• 2013

세계적으로 선박 교통량 증가와 함께 선박 사고 원인의 90% 이상을 차지하는 인적요인에 대한 심층적인 연구의 필요성이 대두되고 있다. 해상교통관제 업무는 고도의 주의와 예측능력을 요구하며 이를 저해하는 인적요인 분석 및 관리 필요성이 절실한 분야이다. 특히 관제업무는 교대근무 등의 불규칙한 근무형태로 인해 발생되는 피로와 업무 집중력 저하, 스트레스가 많은 업무이다. 무엇보다 관제 업무는 해상안전에 핵심적인 역할을 하는데, 관제사의 피로와 스트레스로 인한 업무 차질은 자칫 안전사고로까지 이어질 수 있는 위험이 존재한다. 이렇듯 인적요인이 중요한 영역임에도 불구하고 관제사들의 체계적인 스트레스 관리에 대한 방안은 미비한 실정이다. 본 연구에서는 직무스트레스 유발요인, 유발결과 및 설문조사를 통하여 관제사들의 직무스트레스 현 실태를 파악하고자 한다. 그리고 연구결과를 바탕으로 관제사의 피로, 스트레스를 관리하기 위한 방안과 더 나아가 효율적인 인적요인 안전관리 방안을 모색하고자 한다.

• Journal of Navigation and Port Research
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• v.32 no.3
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• pp.179-184
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• 2008

The aim of this paper is to establish the evaluation system of port logistics of Incheon using the QFD(Quality Function Deployment) model. The research methodology is consisted of four phases. The first step is to investigate the important factors consisting the port logistics of Incheon and then calculate the weighting of factors by Analytic Hierarchy Process (AHP). The second step is to draw out the degree of inter-relation among factors by Fuzzy Subordination Relations (FSR). At the third step, the established system through the QFD method using results of the first and second steps will be used to evaluate and diagnosis the level of port logistics of Incheon. Finally, the sensitivity analysis will be performed and the degree of improving port logistics will be presented according to the rising the relevant factors.

• Journal of Korea Port Economic Association
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• v.30 no.3
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• pp.121-140
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• 2014

The purpose of this study is to identify economic benefits for analyzing the future port and propose an appropriate estimation model. This research has conducted the empirical analysis in order to examine the developed research model. First of all, several existing economic benefits are reviewed and the list of benefits, are able to quantify and characterizable, is selected for the next step. We test the application possibility of the proposed model applying for the three suggestions(AS/RS, OSS, Sky Rail) which are based on "Development of Smart Green Container Terminal Technology." The results of this paper are as follows: Firstly, all of the alternatives are proved economic validation because the values of B/C analysis are over 1.0. Secondly, sensitive analysis is attempted to test unforeseeable circumstances based on the cost increases. The result of the test is identified economic validation as well. Lastly, we convince that the proposed research model in this study is particularly applicable to future container terminal so-called "eco-friendly and fully automated container terminal with high productivity."

• Journal of Korea Port Economic Association
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• v.33 no.1
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• pp.75-87
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• 2017

The purpose of this study is to utilize the system dynamics to carry out a medium and long-term forecasting analysis of the bunker price. In order to secure accurate bunker price forecast, a quantitative analysis was established based on the casual loop diagram between various variables that affects bunker price. Based on various configuration variables such as crude oil price which affects crude oil consumption & production, GDP and exchange rate which influences economic changes and freight rate which is decided by supply and demand in shipping and logistic market were used in accordance with System Dynamics to forecast bunker price and then objectivity was verified through MAPEs. Based on the result of this study, bunker price is expected to rise until 2029 compared to 2016 but it will not be near the surge sighted in 2012. This study holds value in two ways. First, it supports shipping companies to efficiently manage its fleet, offering comprehensive bunker price risk management by presenting structural relationship between various variables affecting bunker price. Second, rational result derived from bunker price forecast by utilizing dynamic casual loop between various variables.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.61-70
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• 2004

This paper treats optimal route assessment system at seaway based on weather forecasting and wave measurement through observation. Since early times. captain & officer have been sailing to select the optimum route considering the weather ana ship status condition empirically. However. it is rare to find digitalized onboard route support system whereas weather fax or wave and swell chart are utilized for the officer. based on officer's experience. In this paper, optimal route assessment system which is composed of voyage efficiency and safety component is introduced. Optimum route minimized ETA (estimated time of arrival) ana fuel consumption is evaluated for efficient voyage considering speed loss and power increase based on wave added resistance of ship. In the view point of safety, seakeeping prediction is performed based on 3 dimensional panel method. Basically. the weather forecast is assumed to be prepared previously in order to operate this system.

• Journal of Navigation and Port Research
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• v.28 no.10 s.96
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• pp.833-841
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• 2004

This paper treats optimal route assessment system at seaway based on weather forecasting and wave measurement through observation Since early times, captain & officer have been sailing to select the optimum route considering the weather and ship status condition empirically. However, it is rare to find digitalized onboard route support system whereas weather fax or wave and swell chart are utilized for the officer, based on officer's experience. In this paper, optimal route assessment system which is composed of voyage efficiency and safety component is introduced. Optimum route minimized ETA(estimated time of arrival) and fuel consumption is evaluated for efficient voyage considering speed loss and power increase based on wave added resistance of ship. In the view point of safety, seakeeping prediction is performed based on 3 dimensional panel method. Basically, the weather forecast is assumed to be prepared previously in order to operate this system.

• The Journal of the Acoustical Society of Korea
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• v.37 no.5
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• pp.263-270
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• 2018

In most industry fields concerning external flow noise problems, the hybrid computational aeroacoustic techniques based on the FW-H (Ffowcs Williams and Hawkings) equation are widely used for its numerical efficiency. However, when the surface integral form of FW-H equation is used without volume quadrupole sources, it is known to generate significant non-physical noise in a certain case. Especially, in the case of a flow in which the tip vortex cavitation is formed in the distant downstream direction such as flow driven by an underwater propeller, the accuracy in noise prediction becomes poor unless it is not properly modelled. Therefore, in this study, the nonphysical acoustic waves caused by the surface integral form of FW-H equation is reduced by adding the quadrupole correction term. First, to verify the accuracy of the in-house code of FW-H equation, the noise by an axial fan used in the outdoor unit of air conditioner was calculated and compared with the results of ANSYS Fluent. In order to verify the effects of the quadrupole correction term, the noise prediction for isentropic vortex convection is performed and it is confirmed that the error is reduced by the quadrupole correction term. Finally, the noise prediction is performed for the flow field generated by the Clark-Y hydrofoil in underwater. It is confirmed that the error caused by the cavitation passing through the integral surface can be reduced by the quadrupole correction term.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.337-339
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• 2007

The productivity of container terminal is usually regarded same as the productivity of quay crane. Operation of quay crane for the export is started from picking up a container in yard block. In doing so, smooth flow of container is vital to maximize the productivity of quay crane. Improvement of quay crane's productivity means improvement of entire productivity in container terminal, which reinforces the competitiveness of terminal consequently. Setting effective plan is essential to improve work flow from yard to quay crane. For optimal plan, it is necessary to gather information about exact time schedule of come-and-go containers for loading, amount of containers that will be come to terminal. Generally, the arrival time of containers and the amount of containers are definite and predictable. However, in the case of export container, the arrival time of containers is random and unpredictable. This study examines the pattern of coming-in containers as time goes in container yard and provides the solution to how to plan export yard considering the change of state in terminal and adapt it to container yard plan