• 한국항해항만학회지
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• 제26권3호
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• pp.275-280
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• 2002

해상에서 발생한 선박충돌사고 재결과정에서 당사자들의 진술을 통하여 해도나 플로팅용지에 충돌선박의 항적을 플로팅하는 과정을 삼각자 및 디바이더를 이용한 수작업에 의존함으로써 많은 시간이 소모되고 오류가 발생하는 문제점이 대두된다. 따라서 본 논문에서는 다양한 충돌상황에서도 충돌선박 당사자들의 진술내용을 컴퓨터에 입력하여 초인시부터 충돌에 이르기까지 양선박의 시간대별 거동을 그래픽과 수치 및 텍스트로 제시함으로써 충돌당사자 진술의 진위여부를 판단할 수 있고 해양안전심판의 정확도도 높일 수 있는 충돌사고 분석시뮬레이터를 제안하였으며, 해상선박충돌사고 실례들을 시뮬레이터에 적용하여 그 유효성을 확인하였다.

• 수산해양기술연구
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• 제34권1호
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• pp.30-36
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• 1998

Recently, with rapid increase of gas demand, there occurs much interest their security of safety in the gas storage tanks and pressure vessels etc. In order to solve the problems, the occurrence of corrosion fatigue crack and the propagation behavior must be investigated. Especially the occurrence of corrosion fatigue crack and the propagation behavior in the part which has concentrated stress or defects, must be studied more carefully. In this paper, the high-tensile steel of SPV 50 which is much used for building the LPG storage tanks was tested by the use of a plane bending corrosion fatigue tester under the various marine environments and in the air. These experiments were done to investigate the corrosion fatigue crack propagation behavior, the variation of aspect ratio for part through crack and electro-chemical characteristics of the metal. The main results obtained are as follows ; 1. Comparing the same surface crack length with the crack depth, the crack depth toward the thickness of specimen in air propagated faster than that in corrosion environment. 2. The aspect variation of the half elliptical crack can be estimated as following equation; b/a=i-jb/t where a : surface crack length, b : crack depth, t : specimen thickness, i,j : experimental constants but the slope j is decreased as specific resistance decreases. 3. As the specific resistance of corrosion environment decrease or the corrosion fatigue crack propagates, the corrosion potential become less noble.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2006년도 추계학술대회 학술발표 논문집 제16권 제2호
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• pp.39-44
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• 2006

Ship's collision avoidance is a skill that masters of merchant marine vessels have acquired through years of experience and that makes them feel at ease to guide their ship out from danger quickly compared to inexperienced officers. Case based reasoning(CBR) uses the same technique in solving tasks that needs reference from variety of situations. CBR can render decision-making easier by retrieving past solutions from situations that are similar to the one at hand and make necessary adjustments in order to adapt them. In this paper, we propose to utilize the advantages of CBR in a support system for ship's collision avoidance while using fuzzy algorithm for its retrieval of similar navigational situations, stored in the casebase, thus avoiding the cumbersome tasks of creating a new solution each time a new situation is encountered. There will be two levels within the Fuzzy-CBR. The first level will identify the dangerous ships and index the new case. The second level will retrieve cases from casebase and adapt the solution to solve for the output. While CBR's accuracy depends on the efficient retrieval of possible solutions to be adapted from stored cases, fuzzy algorithm will improve the effectiveness of solving the similarity to a new case at hand.

• 한국해양공학회지
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• 제31권2호
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• pp.121-129
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• 2017

The present study numerically investigated the influence of the waveform distribution on the tsunami-vegetation interaction using a non-reflected wave generation system for various tsunami waveforms in a two-dimensional numerical wave tank. First, it was possible to determine the wave attenuation mechanism due to the tsunami-vegetation interaction from the spatial waveform, flow field, vorticity field, and wave height distribution. The combination of fluid resistance in the vegetation and a large gap and creates a vortex according to the flow velocity difference in and out of the vegetation zone. Thus, the energy of a tsunami was increasingly reduced, resulting in a gradual reduction in wave height. Compared to existing approximation theories, the double volumetric ratio of the waveform increased the reflection coefficient of the tsunami-vegetation interaction by 34%, while decreasing the transfer coefficient and energy attenuation coefficient by 25% and 13%, respectively. Therefore, the hydraulic characteristics of a tsunami is highly likely to be underestimated if the solitary wave of the approximation theory is applied for the tsunami.

• 한국항해항만학회지
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• 제43권5호
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• pp.320-327
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• 2019

This study examined the port expansion plan for the fishery port at the east coast of Korea, in accordance with permission conditions for coastal ports such as a limit on the cargo volume and passenger demand for the coastal tourism belt formation. The site was chosen as a municipal coastal port attracting the new ocean industry and building waterfront zone as a hub of new marine tourism. Two different numerical models (Swan and Bouss 2D) were used. Before applying to the target sea area, some numerical tests were conducted for the variation according to Bouss-2D's strong/weak and nonlinear technique compared to the irregular diffraction of semi-infinite breakwater with a theoretical solution. As a result, there was a difference in strong nonlinearity with breaking waves and it was necessary to experiment with a strong nonlinear analysis technique for the actual site. Two numerical models were applied to the fishery port site and the tranquility of some alternatives were analyzed. The numerical results show the most suitable plan was ALT-1, with satisfied harbor tranquility and reasonable economic sense. The extension of the east breakwater and enlarged turning basin of the F-Land plan have brought generally more stable harbor tranquility than the ALT-1. The result can be used as a reference for the port expansion plan in the future.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.192-194
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• 2015

The growing size and complex process in construction project recently leads to increase risk and the losses as well. Even though researchers have identified the major risk indicators, there is lack of comprehensive and quantitative research for identifying the relationship between the risk indicators and economic losses associated with construction projects. To address this shortage of research, this study defines risk indicators and create a framework to assess the influence of economic losses from the indicators. An insurance company's claim payout record was accepted as the dependent variable to reflect the real economic losses. Based on the claims, we categorized the causes and results of accidents. To establish framework, built environment vulnerability indicators and geographical vulnerability indicators were employed as the risk indicators. A Pearson correlation analysis was adopted to validate the relationship with loss ratio and risk indicators. Consequently, this framework and its results may offer significant references for under writers of insurance companies and loss prevention activities.

• ALGAE
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• 제39권2호
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• pp.59-74
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• 2024

Terrestrial cyanobacteria are extremely diverse. In urban areas, they can be found as black stains on the surface of building walls, stone monuments, or man-made structures. Many of the terrestrial cyanobacteria are still understudied. To expand knowledge of terrestrial cyanobacterial diversity, a polyphasic characterization was performed to identify 12 strains isolated from campus of University of the Ryukyus, Okinawa, Japan. Multigene phylogenetic analyses based on 16S rRNA gene and 16S-23S rRNA internal transcribed spacer (ITS) region showed that the isolated strains formed two independent subclades within Nodosilinea, and were distantly related to all described Nodosilinea species. The 16S-23S rRNA ITS secondary structures showed variations for D1-D1' and Box B domain, while V3 domain was almost identical among entire species of Nodosilinea, including the studied strains. In addition, a unique morphological character, i.e. forming nodule or spiral shape, was also observed in certain studied strains. According to polyphasic characterization, Nodosilinea coculeatus sp. nov. and Nodosilinea terrestrialis sp. nov., were proposed as two new species of terrestrial cyanobacteria from Okinawa.

• 방사선산업학회지
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• 제18권2호
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• pp.109-115
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• 2024

As a global effort for eco-friendly, the ship building is making great efforts to develop ships using low-carbon, eco-friendly alternative fuels. Nuclear energy, one of several eco-friendly alternative energy sources, is evaluated as an effective alternative for future ships by minimizing carbon emissions and securing economic feasibility with low power generation cost. However, although appropriate regulatory requirements are necessary for commercialization of nuclear powered ships, there are currently no regulatory requirements for nuclear powered ships in Korea. In this study, accordingly, domestic and international regulatory requirements related to nuclear powered ships were reviewed, matters to be considered in terms of safety when developing domestic marine nuclear reactor regulatory requirements were derived, and a licensing regulatory system for nuclear powered ships was derived.This study is expected to be used as basic reference data when developing regulatory requirements for nuclear powered ships.

• 한국석유지질학회지
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• 제12권1호
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• pp.27-33
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• 2006

북한의 서한만 분지는 일일 생산량 450 배럴의 원유가 생산되고 있어 석유부존 가능성이 확인되었고, 중국에서 큰 유전중 하나인 발해만 유전지대와 지리적으로 근접해 있어 대규모 매장 가능성도 있다. 지금까지 북한의 석유탐사 및 투자 현황을 살펴보면, 탐사가 진행중인 곳은 3개 지역으로 서한만 B&C 광구 (스웨덴 Taurus사), 북부 서한만 및 육상 안주분지 (캐나다 SOCO사), 동한만 광구 (호주 Beach Petroleum사) 등이다. 상기 이외의 해저에는 원유가 부존할 만한 분지가 존재하지 않으며, 길주-명천 지구대 등 일부 육상 지역에서는 원유가 발견된 곳도 있으나 경제성이 없는 것으로 추정된다. 지금까지 밝혀진 북한 서한만의 지질은 중국의 발해만과 유사하다. 후기 원생대와 초기 고생대에 생성된 기반암 위에는 최대 $6,000{\sim}10,000\;m$ 두께의 중생대 탄산염암 및 퇴적암과 $4,000{\sim}5,000\;m$ 두께의 신생대 퇴적암이 집적되어 있다. 근원암은 3,000 m 이상되는 쥬라기 및 $1,000{\sim}2,000\;m$ 두께의 백악기 흑색 셰일 그리고 수천 m 두께의 중생대 이전의 탄산염암으로 구성되어 있다. 저류층은 높은 공극률을 가진 중생대부터 신생대에 퇴적된 사암과 중생대전에 균열된 탄산염암이다. 원유 트랩은 배사구조, 단층구조, 파묻혀 있는 언덕 (buried hill) 그리고 층서형 트랩 형태다. 따라서 서한만에서의 퇴적층들은 다양한 형태의 근원암을 가지며 또한 공극률과 투수율이 높고, 많은 단층에 의한 이동경로를 가지게 되므로, 사암으로 이루어진 석유 저장지만 발견하면 석유를 생산할 수 있을 것으로 추정된다. 연안국의 200해리 배타적 경제수역 설정 등 해양관할권 확대가 주류를 이루는 새로운 국제해양질서가 구축되고 있는 상황과 동일한 해역을 대상으로 하는 남북한 해양개발의 인접성 등을 감안할 때, 실리주의적 세계의 변화에 공동으로 대처하고 남북한 상호 경제발전을 도모하기 위해서는 남북한 해양과학기술 협력교류의 활성화와 새로운 첨단 해양기술의 공동 연구 개발 둥 남북 상호간의 능동적이고 적극적인 협력자세가 무엇보다 필요하다고 생각된다. 또한 한반도 주변해양에서 남북한 각기 독자적인 해양관리 및 해양산업의 전개보다는 양국 공동협력에 의해 주변국의 한민족 공동체가 참여하는 방안이 시급한 과제라고 판단된다.

• 해양환경안전학회지
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• 제24권5호
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• pp.569-575
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• 2018

북극에 대한 관심이 높아지면서 쇄빙연구선의 필요성이 점점 커지고 있다. 특히 우리나라의 경우 2009년 진수된 7,500톤급의 아라온호가 유일한 쇄빙연구선인데, 현재 아라온호만으로는 북극과 남극의 관련 연구를 수행하는데 어려움이 있다. 이에 해양수산부에서는 제2쇄빙연구선의 건조를 추진 중에 있는데 제2쇄빙연구선 건조의 필요성과 규모의 적정성에 대한 논란이 있으므로 이러한 논란을 줄이고 보다 합리적인 의사결정을 위해서는 제2쇄빙연구선의 경제적 가치를 추정하는 것이 중요하다. 본 연구는 비시장재화의 가치측정방법론인 조건부 가치측정법을 활용하여 제2쇄빙연구선의 경제적 편익을 산정하였다. 특히 본 연구의 추정방법과 관련하여 통상적인 CVM은 가정되는 분포의 형태와 추정모형에 따라서 WTP 분석결과에 편차가 발생하게 된다. 이에 본 연구에서는 베이지안 추정법(Bayesian approach)을 활용한다. 분석결과에 따르면 가구당 연간 평균 WTP는 1,999원으로 추정되었으며 이를 전국 가구 수로 확대한 제2쇄빙연구선 건조 사업에 대한 총편익은 연간 약 373.9억 원인 것으로 산정되었다.