• Journal of Advanced Marine Engineering and Technology
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• v.32 no.8
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• pp.1192-1200
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• 2008

This paper is concerned with the thermal design of the $138,000m^3$ class membrane type LNGC. To predict the temperature distribution, BOG and BOR, 3-dimensional numerical calculation was carried-out for the quarter of No.3 LNG tank. These sequence analyses were performed under the standard conditions of IMO ship design condition, USCG ship design condition and the Korean flag LNGC's route condition according to the 6-voyage modes. As the results, temperature behavior, heat flux, total penetrating heat, BOG and BOR were obtained, and those were compared with the maneuvering results considering the real temperature variation of air and sea water temperature at noon time. For securing the safety of LNGC during the ballast voyage, optimum control patterns of pressure and temperature in LNG tank is suggested in this paper.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.06a
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• pp.458-460
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• 2012

1970년대에는 일반적으로 상선에 30-40명의 선원이 탑승했었지만, 최근에는 선박의 자동화와 경제적 문제 때문에 점점 선원수를 줄이고 있는 실정이다. 그러나 최근 통계에 따르면 해양사고의 약 80% 정도가 human error에 의해 발생하고 있으며, 이러한 이유중의 하나는 선원 1명당 부과되는 작업량 과다에 있기도 하다. 즉 선원수의 감소는 업무 또는 작업량의 증가를 가져왔고, 하루에 14-18시간 일하는 것은 특별한 일이 아니게 되었다. 따라서 사고의 증가를 유발하지 않는 범위 내에서 선원수의 감소 범위 산정은 경제적 문제로 인해 크게 대두되고 있다. 현재 안전성과 효율성을 고려한 선원수 산정에 대한 정확한 근거 및 산정자료는 없지만, 최근 IMO, 미해안경비대 (US Coast Guard ; 이하 USCG) 등에서 안전승무정원(safe manning)에 관한 논의 및 연구가 진행되고 있다. 본 논문에서는 선박의 안전승무정원의 평가모델에 대한 최근 국내외 연구현황을 정리하고, 국내 수용을 위한 방안을 제시하고자 한다.

• Journal of Environmental Science International
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• v.24 no.9
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• pp.1181-1188
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• 2015

In this study, we discussed about the application of the single physical and chemical treatment processes and the physical-chemical complex treatment processes on the inactivation of Artemia sp. in order to satisfy the USCG Phase II (United States Coast Guard). The results showed that initial disinfection rate of ultrasonic process in single batch process is higher than that of electrolysis. However, the inactivation rate showed slower than electrolysis. The inactivation rate of Artemia sp. on the single continuous treatment process ranked in the following order: homogenizer > electrolysis > ultrasonic process. Inactivation rate of Artemia sp. in continuous homogenizer-electrolysis complex process was reached at 100% immediately. A synergistic effect of ultrasonic-electrolytic complex process was found to be a small. The order of processes in a complex process did not affect the disinfection performance.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.06a
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• pp.29-30
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• 2011

GNSS 시스템의 다원화에 따른 DGPS RSIM 기능도 DGNSS 체제로 기능적, 시스템적 고도화가 필요한 시점이 도래하고 있다. 이와 관련하여 차세대 DGNSS RSIM 아키텍처를 미국 해양경비대(USCG) NAVCEN에서 제안하였는데, 이 차세대 DGPS RSIM 아키텍처의 기본 요구조건은 PC 플랫폼 기반의 신규 신호 및 기술에 대한 충분한 유연성을 확보할 수 있고, 기존 사용자 수신기와 기존 기준국 시스템과의 충분한 호환이 가능해야 한다는 것이다. 그러나 위의 제시된 아키텍처는 DGPS RSIM 시스템의 소프트웨어 응용에 초점이 맞추어져 있어서 GNSS 다원화에 따른 DGNSS 기준국 기능 고도화에 한계가 있다. 그러므로 본 논문에서는 소프트웨어 DGNSS RSIM 개발을 위한 후속연구로서, 현재 운영 중인 GPS/GLONASS를 중심으로 보정정보 생성 및 그 측위정확도 성능분석에 중점을 두고자 한다. 기 설계된 DGNSS 소프트웨어 RSIM 아키텍처에 대해 설명하고, 설계된 아키텍처와 통합보정정보 생성 및 처리 기법이 적용된 GPS/GLONASS 통합보정시스템을 구현하여, 향후 소프트웨어 DGNSS RSIM을 위한 측위정확도 측면에서의 성능을 분석한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.10a
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• pp.263-265
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• 2015

미국은 우리나라와 같이 전국망 DGPS 인프라를 운영하고 있는 국가 중에 하나로 DGPS 서비스를 해양분야 뿐만 아니라 육상분야에도 제공하고 있는 대표적 국가이다. 지난 8월 18일 미 정부는 연방공보를 통해 현재 운영 중인 전국망 DGPS 서비스의 대규모 개편 계획을 공표한 바 있다. 공표된 계획에 따르면, 2016년 1월 15일부로 육상에서의 DGPS 서비스는 중단되고, 해양에서의 DGPS 서비스도 크게 영향을 받을 것으로 예측되고 있다. 따라서 본 논문은 우리나라와 유사한 형태의 DGPS 인프라를 운영하고 있는 미국이 전국망 DGPS 서비스를 개편하게 된 배경과 원인에 대해 살펴본다. 그리고 미국이 공표한 계획의 실행 전망과 쟁점에 대해 알아본다. 마지막으로 미국의 NDGPS 서비스 운영정책 변화가 우리에게 전달하는 시사점을 제시한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.426-433
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• 2020

This study aimed to compare the pretreatment methods of phytoplankton for type approval of the Ballast Water Treatment System (BWMS). The International Maritime Organization (IMO) and the United States Maritime Police (USCG) use two different test methods for this purpose. To compare the two methods, a test for concentration and non-concentration was performed with cultured and natural phytoplankton, and samples from the land-based BWMS test. The extent of damages caused by the process of concentration varied between cultured and natural species, indicating differences depending on the physiological and morphological characteristics of the species. In the land-based test, in the control water with a high biological population, the number of non-concentrated samples was about twice as high as that of the concentrated samples. There was no distinct difference between the two methods in the treated water with a low biological population. Thus, although there is a difference between concentration and non-concentration for phytoplankton sampling, the concentration method can be applied as a method of evaluating BWMS performance. However, a method for evaluating whether live species in treated water may be lost or damaged during the concentration process of sampling should be developed and validated.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.4
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• pp.222-230
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• 2023

In the present work, the scale effect on the Boil-Off Rate (BOR) was investigated based on an analytical method to systematically evaluate the thermal performance of a Liquefied Natural Gas (LNG) Cargo Containment System (CCS). A two-dimensional thermal resistance network model was developed to accurately estimate the heat ingress into the CCS from the outside. The analysis was performed for the KC-1 LNG membrane tank under the IGC and USCG design conditions. The ballast compartment of both the LNG tank and cofferdam was divided into six sections and a thermal resistance network model was made for each section. To check the validity of the developed model, the analysis results were compared with those from existing literature. It was shown that the BOR values under the IGC and USCG design conditions were agreed well with previous numerical results with a maximum error of 1.03% and 0.60%, respectively. A SDR, the scale factor of the LNG CCS was introduced and the BOR, air temperature of the ballast compartment, and the surface temperature of the inner hull were obtained to examine the influence of the SDR on the thermal performance. Finally, a correlation for the BOR was proposed, which could be expressed as a simple formula inversely proportional to the SDR. The proposed correlation could be utilized for predicting the BOR of a full-scale LNG tank based on the BOR measurement data of lab-scale model tanks.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.4
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• pp.324-331
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• 2024

The height of large car and truck carriers from the keel to the wheel house is 44 ~ 46 m, and as the car-carriers increases in size, it exhibits the 'top heavy' characteristic, where the upper section is heavier than the lower section. This study aims to estimate the maximum outward heel angle of the Golden Ray car-carrier (G-ship) during turning maneuvers for accident investigation and the prevention of similar accidents. The theoretically calculated maximum outward heel is 7.5° (at 19 kn, rudder angle 35°) with a GM of +3.0 m or higher, and 16.7° with a GM of +1.85 m. Meanwhile the experimentally modified maximum outward heel is 10.5° (at 19 kn, rudder angle 35°) with a GM of +3.0 m or higher, and 23.3° with a GM of +1.85 m. The G-ship is maneuvered during an accident at a speed of 13 kn, at starboard rudder angle of 10° to 20°, it changes course from 038°(T) to 105°(T) based on the instructions of the on-board pilot. At this time, the maximum outward heel is estimated to be between 7.8° and 10.9° at the port side, which is 2.2 times higher than the normal outward heel. In the IS code, cargo ships are required to exhibit a minimum GoM of +0.15 m or more. The maneuvered G-ship exhibits a GoM of +1.72 m. It is not maneuvered because it fails to satisfy the international GoM criteria and because its GoM is insufficient to counteract the heeling moment during the maneuver. This study is performed based on accident-investigation results from the Korea Maritime Safety Tribunal and the USCG.

• Journal of the Korean Society of Marine Environment & Safety
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• v.9 no.1
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• pp.79-87
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• 2003

To improve the educational system of Korea Maritime Police Agency(KMPA), the authors investigate and evaluate the present course and curricula in details comparing with the systems of US Coast Guard and Japanese Coast Guard As a result, it is suggested that KMPA try to recruit good-quality officers through the diverse route, develop the future-oriented educational, system, adjust the course and curricula to meet KMPA's role and mission for 21st century. Besides, it requires that KMPA establishes its own institute to carry out the recruit training and re-freshening courses for both the officers and enlisted person.

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.1
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• pp.77-82
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• 2008

Recently, fatigue related to marine accidents was recognized to be very important contribution factor when marine accidents such as collision, aground, fire, etc. were investigated Many studies concerned about fatigue factors related to human error can be found. In this study, the analysis and examination of USCG Fatigue Investigation Program were carried out in order to investigate marine accidents happened in Korean waters. The Fatigue Investigation Program was established on the MAIFA(Marine Accident Investigators Forum in Asia) web site. Finally, the application plan of the program was discussed.