• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.6
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• pp.646-653
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• 2018

Marine accidents caused by dragging anchors occur constantly due to enlargement of ships' size and unusual weather conditions. Nevertheless, vessel operators rely on their experience because the calculations of actual holding power and external forces are complex and inconvenient. The purpose of this study was to propose a program for the anchor dragging risk assessment in order to provide crew and VTSO with the information to determine easily the danger of dragging and take appropriate action. The input data in this program were composed of the ship's basic particulars, anchoring condition, and external environment etc. on calculating for the wind pressure, frictional force, drift force, and holding power. Three dragging anchor accidents were applied to the program's data input at the time of the day, then the result was assessed by 'warning', which was verified with a high confidence. As a result, the risk of dragging anchors can be predicted in advance through this program. In further studies, it is necessary to simplify the input data and improve user convenience through automatic input from various equipment.

• Journal of Korean Society of Transportation
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• v.30 no.5
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• pp.91-100
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• 2012

Although Korea's coastal areas increasingly experience marine accident due to frequent ship encounters, increased vessel traffic and large vessel, there is a no specific model to evaluate the navigating vessel's risk for the given situation. The maritime transport environmental assessment is necessary due to the amended marine traffic law. However, marine safety diagnosis is now evaluated by foreign models. In this paper, therefore, we suggest a domestic model catering to and reflecting the characteristics of Korea's costal areas as well as those of vessel navigator's risk. We can evaluate subjective risks using this model, and can establish the model output as maritime risk exposure assessment system. We have performed analyses of variance and multiple comparison to identify the factor affecting subjective risks. As a result, measurable subjective risks of maritime traffic accident based on our suggested model can be expressed using the maritime risk exposure assessment system with geographic information system.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.1
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• pp.26-32
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• 2017

Enlargement and speed-up of a ship and diversification of ship's type have served to greatly increase the importance of marine transport means. It's reported that accident occurrence frequency of collision is high next to engine damage among the ship accident types, and that the accident ratio according to human factors is also high. In addition, ship accidents come to occur caused by complex cause factors rather than a sole cause factor, it is necessary to investigate the cause factors through the written verdict. This study proposed the cause factors of collision ship accident on the basis of human factors in collision ship accident among the written verdicts provided by the Korean Maritime Safety Tribunal, and inquired into the cause factor and effect through the correlation analysis of accident occurrence factors. Also, this study predicted the collision accident through analyzed the major cause factor of the occurrence at the zero minute when collision on the basis of the time taken from the time point of detecting collision of ships to the time point of collision occurrence. This study used commercial software-Statistical Package for Social Sciences (SPSS Ver21.0) to do correlation analysis. For time analysis, this study analyzed the cause factor and time by analyzing the time taken from the time point of detected ships to the time point of collision occurrence on the basis of the written verdicts. The study analysis showed that there were many cases of collision ship accidents occurrence caused by more than two sorts of cause factors, and that the case (zero minute) where there is no time to spare for collision avoidance accounted for 36.1 %, and negligence in guard or surveillance of the other ship, and sailing while drowsy, or drinking was a contributor to an accident. Poor watch keeping is very strong relationship with pool ready for sail.

• Journal of Internet Computing and Services
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• v.22 no.2
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• pp.59-68
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• 2021

As artificial intelligence(AI) technologies, which have made rapid growth recently, began to be applied to the marine environment such as ships, there have been active researches on the application of CNN-based models specialized for digital videos. In E-Navigation service, which is combined with various technologies to detect floating objects of clash risk to reduce human errors and prevent fires inside ships, real-time processing is of huge importance. More functions added, however, mean a need for high-performance processes, which raises prices and poses a cost burden on shipowners. This study thus set out to propose a method capable of processing information at a high rate while maintaining the accuracy by applying Quantization techniques of a deep learning model. First, videos were pre-processed fit for the detection of floating matters in the sea to ensure the efficient transmission of video data to the deep learning entry. Secondly, the quantization technique, one of lightweight techniques for a deep learning model, was applied to reduce the usage rate of memory and increase the processing speed. Finally, the proposed deep learning model to which video pre-processing and quantization were applied was applied to various embedded boards to measure its accuracy and processing speed and test its performance. The proposed method was able to reduce the usage of memory capacity four times and improve the processing speed about four to five times while maintaining the old accuracy of recognition.

• Journal of Navigation and Port Research
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• v.29 no.1 s.97
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• pp.29-34
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• 2005

A mis-handling of the ship operators, treated as one qf the main causes of a ship accidents, normally has caused a ship to collide with obstacles like a reef, a rock and other ships etc. since their ability has been declining little by little even though the port conditions have been getting worse. The ship needs a highly sophisticated technology as her size and speed increase as the ship have been demanded. For example, Auto Avoidance Control System gradually has been receiving a growing interest to control the entire ship safely. From that purpose, this research has been done. The research was based on the MMG mathematical model, used Surge-Sway-Yaw-Roll motion equation and Fuzzy theory for calculating the collision-risk Also the research successively was done when the ship encountered continual multitude ships.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.31 no.4
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• pp.423-434
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• 1995

It was used boundary element method(BEM) and analysed axisymmetric problem to solve hydraulic cylinder for large vessel acting uniform internal pressure(25N/m super(2)) within elastic limit. This paper was utilized the carbon steel tubes for machine structural purposed model, inner radius was 150mm and outer radius was 250mm, axial length was semi-infinite and the isoparametric element was used. The important results obtained in this study were summarized as follows. Radial, tangential and shearing stress occured the maximum stresses(48, -20 and 34MPa) at the inner radius and the minimum stresses(32, -4 and 18MPa) at the outer radius of the hydraulic cylinder for large vessel. But negative signs have meaning compressive stress and stress diminution ratio was about 0.15MPa/mm. The use of isoparametric element raised accuracy and the increment of input data lessened the error in internal point but computer run-time was increased. The double node was improved the internal solutions to settle discontinuity at corner and the double exponential formula lessened error of stress value at boundary neighborhood. And then coincidence between the analytical and exact results is found to be fairly good, showing that the proposed analytical by BEM is reliable.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.4
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• pp.309-316
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• 2020

Waterway design should prioritize appropriate channel width to ensure preferential safe passage for the arrival and departure of vessels. To calculate the minimum channel width required for safe passage a comprehensive review of several factors is required. These factors include vessel maneuverability, determined by vessel size, type and speed; environmental factors such as wind, tide, and wave action; human factors, including personal experience and operator judgment as well as marine traffic and navigation support facilities for decision making. However, the Korean channel width design standard is based only on vessel length, and requires improvement when compared with the standards of PIANC, USA, and Japan. This study aims to estimate the appropriate channel width required for one-way traffic in a straight channel, considering various vessel and environmental factors, using Fast Time Simulation (FTS). When the wind speed is 25 knots, with a current speed of 2 knots and a normal vessel speed of 10 knots FTS shows that a 150K GT Cruise Ship requires a minimum channel width of 0.67-0.91 the vessel length (L), whereas a 120K TEU Container Ship and a 300K DWT VLCC require 0.79-1.17 and 1.02-1.59, respectively. Such results can be used to calculate the minimum channel width required for safe passage as an improved Korean design standard.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.04a
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• pp.74-75
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• 2010

국제교류의 증가와 물동량 증가에 따른 선박의 초대형화로 인해 각 나라의 항만들도 대형화되고 있다. 국내 항만들도 국제적인 추세에 따라 대형항만의 건설에 박차를 가하고 있다. 하지만 무분별한 항만 개발과 글로벌 경제위기로 인한 물동량 감소는 우리나라 중소형항만의 물동량이 감소하는 원인이 되었고, 이는 결국 항만시설 공급과잉 현상의 원인이 되었다. 이에 본 연구에서는 국내 중소형항만들의 공급과잉 현상을 극복하기 위한 방안들과, 중소형항만들의 발전전략을 제시하고자 한다.

• Proceedings of the Korea Port Economic Association Conference
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• 2007.10a
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• pp.175-197
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• 2007

컨테이너 선박의 대형화, 항만의 중심항과 주변항으로 체제 변화 등과 같은 항만 환경의 변하는 항만간의 경쟁을 심화시키고 있다. 선행연구에서 항만경쟁력 요인 분석을 통해 항만물류 서비스품질 또한 한 요인임을 밝혔다. 기존의 항만물류 서비스품질에 대한 연구에서 항만물류 서비스품질을 통한 고객만족에 관한 연구는 많지만, 항만물류 서비스품질의 선행변수에 대한 연구는 미비했다. 따라서 본 연구에서는 항만물류 서비스품질이 선행변수로 전략지향성의 요인인 혁신지향성, 고객지향성, 경쟁자지향성을 선정하여 이들의 관계를 규명하고자 하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.06a
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• pp.133-134
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• 2009

선박의 대형화와 함께 해운 항만 시장이 급속히 변화하는 가운데 각 항만들은 항만 경쟁력을 가지기 위해 물동량 예측과 더불어 하역료를 바탕으로 한 부두사용료 수준에 대해 검토를 시행하고 있는 실정이다. 또한 부산북항 재개발과 관련하여 일반부두 폐쇄 및 터미널의 이전이 계획되어지는 가운데, 터미널 임대료 및 물동량 배분에 관한 연구가 활발하게 이루어지고 있다. 따라서 본 논문은 컨테이너 터미널의 주변여건 변화에 따른 컨테이너화물 물동량을 추정 및 예측하고, 기존 사용료 및 부산북항의 특정 터미널을 대상으로 향후 2020년까지의 사용료를 검토하고자 한다.