• 해양환경안전학회지
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• 제28권5호
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• pp.791-799
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• 2022

유선 및 도선 중 선박길이 12미터 미만인 소형선박은 선박안전법에 따른 복원성 기준 적용이 면제되며, 유선 및 도선 사업법에 따라 승객 및 선원이 탑승 가능한 면적을 고려하여 승선정원을 정하고 있다. 이러한 유선 및 도선 중에서는 건조 이후 차양의 설치 등 복원성에 영향을 미치는 상부 구조물을 설치하는 사례도 적지 않다. 이에 본 연구에서는 상부 구조물을 설치한 도선에서 실제 발생한 전복사고의 사례를 바탕으로 해당 도선의 복원성을 추정하여 사고 원인을 분석하고자 하였다. 분석 결과, 승선정원을 초과한 상태에서 승객들이 동시에 하선하고자 기립하여 복원성이 악화된 것으로 나타났으나, 해당 도선이 승선정원을 준수하더라도 한쪽 현의 승객들이 기립하면 횡경사에 의한 전복의 가능성이 존재하였다. 따라서, 보다 안전한 유선 및 도선사업을 위하여 선박길이 12미터 미만의 유선 및 도선에 대하여 건조 및 개조 시 실선 복원성 시험에 의한 승선정원 산출, 승선정원의 총중량 한곗값 제시 등을 개선방안으로 제시하였다.

• 한국항해항만학회지
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• 제47권6호
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• pp.376-385
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• 2023

통계에 따르면 어선의 전복 사고는 전체 전복 사고의 절반 이상을 차지한다. 이는 미숙한 조업, 기상 악화, 정비 미흡 등 다양한 원인으로 발생할 수 있다. 업계 규모와 영향도, 기술 복잡성, 지역적 다양성 등으로 인해 어선은 상선에 비해 상대적으로 연구가 부족한 실정이다. 본 연구에서는 이미지 기반 딥러닝 모델을 활용하여 어선의 횡동요 시계열을 예측하고자 한다. 이미지 기반 딥러닝은 시계열의 다양한 패턴을 학습하여 높은 성능을 낼 수 있다. 이를 위해 Xception, ResNet50, CRNN의 3가지의 이미지 기반 딥러닝 모델을 활용하였다. Xception과 ResNet50은 각각 177, 184개의 층으로 구성되어 있으며 이에 반해 CRNN은 22개의 비교적 얇은 층으로 구성되어 있다. 실험 결과 Xception 딥러닝 모델이 가장 낮은 0.04291의 sMAPE와 0.0198의 RMSE를 기록하였다. ResNet50과 CRNN은 각각 0.0217, 0.022의 RMSE를 기록하였다. 이를 통해 상대적으로 층이 더 깊은 모델의 정확도가 높음을 확인할 수 있다.

• 한국항해학회지
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• 제11권2호
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• pp.61-72
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• 1987

When a ship is running in following seas, the encounter frequency is reduced to a very low one. In that case broaching, surfiding and capsizing phenomena are most likely to occur due to wave exciting forces acting on a ship in following seas. In this paper, the emphasis is mainly laid upon transverse stability of ships following seas, which is related to capszing phenomenon. The authors take the case that ship speed is equal to the wave celerity, i.e., the encounter frequency is zero. Hydrostatic force and moment due to Froude-Krylov hypothesis are calculated by line intergral method. Transverse stability is evaluated from hydrostatic force and moment. Through the application of present calculation method to box-shaped vessel, it is confirmed that the transversestability of a vessel can be reduced to critical level at wave crest.

• 해양환경안전학회지
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• 제5권2호
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• pp.45-55
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• 1999

The majority of fishing vessels(under 20 tonnages) in Korea have a high casualty accident of the flood and capsizing occurred by lack of stability. Actually, it is so difficult to make out the data of inclining and stability tests of small fishing vessels after building, because most of them were built on experiences of manufacturer. According to above reasons, the aim of this study is an attempt to propose a stability criteria of small fishing vessels as follows: Firstly, it is examined that the stability is driven from a transverse metacenter height of actual ships, which is able to obtain a basic drawing and stability data. Secondly, it is examined the heeling at high-speed turning, and the period of rolling according to B/D(breadth/depth). Finally, it is suggested the stability criteria by using a dynamic state which is applied in passenger boat and fishing vessels over 24 meters.

• 기술사
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• 제41권5호
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• pp.41-44
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• 2008

해상을 운항하는 선박들은 충돌, 좌초, 침몰, 전복 및 조난 등의 위험에 노출되어 있으므로항행 중에 발생할 수 있는 여러 가지 해양사고의 요인을 살펴보고 방지 대책을 생각해 보았다. 일단 해상에서 사고가 발생할 경우 신속하고 효율적인 구조를 위해 유관기관 사이에 일원화된 지휘체계가 필요하다. 또한 해양사고의예방을 위해서는 선원들에 대한 안전교육을 강화하고 안전한 항행을 위한 항행여건을 개선하는 것이 중요하다.

• 대한조선학회지
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• 제22권2호
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• pp.1-11
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• 1985

Generally, the non-uniform flow with varying speed distribution ca be formed near narrow straits or waterways. One of the most dynamic modes of capsizing can occur as a result of manoeuvring of ships in non-uniform flow. This paper covers the investigation into the factors affecting the likelihood of server ship motions in non-uniform flow. Digital simulation of manoeuvring is carried out in order to predict conditions which could lead to serve ship motions in non-uniform flows. Hydrodynamic force derivatives of a container ship are used. Finally, possible conditions of severe ship motions are suggested and guidelines for reducing the liability to capsize are given both for the ship operator and the naval architect.

• Ocean Systems Engineering
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• 제1권3호
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• pp.249-261
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• 2011

The stochastic nonlinear dynamic behavior and probability density function of ship rolling are studied using the nonlinear dynamical systems approach and probability theory. The probability density function of the rolling response is evaluated through solving the Fokker Planck Equation using the path integral method based on a Gauss-Legendre interpolation scheme. The time-dependent probability of ship rolling restricted to within the safe domain is provided and capsizing is investigated from the probability point of view. The random differential equation of ships' rolling motion is established considering the nonlinear damping, nonlinear restoring moment, white noise and colored noise wave excitation.

• 한국기계가공학회지
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• 제12권1호
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• pp.15-21
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• 2013

The safety and stability of 5MW class offshore wind turbine Jack-up platform was investigated through ocean basin experiment. For simulating the environmental condition of yellow sea in the South Korea, diverse waves, winds and currents were performed based on Froude's number. Regular wave and irregular wave based on Froude's number were applied to the wind turbine structure. In experiments, the height and period of regular wave type were scaled down as the 1:50 ratio of real wave condition. Irregular wave type was simulated with TMA(Texel Storm, Marsen and Arsloe)spectrum. The vertical reaction force, resonance period and wave pressure applied to multi-supporters of wind offshore structure were measured experimentally. Finally, the results showed that the capsizing situation of the offshore structure was generated by the severe environmental condition.

• Selected Papers of The Society of Naval Architects of Korea
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• 제1권1호
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• pp.37-44
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• 1993

Deck wetness phenomenon has long been considered as one of the factors that degrade the performance of a ship In waves. In rough weather, the frequent skipping of water may give rise to the capsizing of the ship. Therefore an appropriate above water bow shape design is an important asset to a ship of which successful performance in rough weather is a prerequisite such as a warship. In this paper an experimental technique for estimation of deck-wetness frequency is presented. The results of the model tests are compared with those of computations using Ochi's formula. Finally the applicability of Ochi's formula is discussed.

• Journal of Hydrospace Technology
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• 제1권1호
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• pp.57-65
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• 1995

For the mechanism of ship capsizing, we can generally consider that it\`s caused due to pure loss of stability, parametric oscillation(low cycle resonance) of ship in waves and the broaching phenomena. Among them, low cycle resonance occurs due to the dynamic change of righting arm with respect to the relative position of ship to waves. The dynamic change depends on the encounter period of a ship in following waves. This paper discusses the following items : (1) An analytical expression of GZ curve varying with respect to the relative position of ship to waves, (2) Non-linear equation of motion describing low cycle resonance, (3) The effects of righting arm, stability range and encounter period on low cycle resonance.