• Journal of Navigation and Port Research
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• v.42 no.6
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• pp.378-387
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• 2018

In this paper, the towing force for the LNG bunkering barge was investigated. Currently, LNG bunkering barge is being developed as an infrastructure for the bunkering of LNG (Liquefied Natural Gas), an eco-friendly energy source. In the case of the LNG bunkering barge, self-propulsion is considered through retrofit from an operating point. Therefore, the LNG bunkering barge's shape is similar to that of the ship as compared to a towed barge, so a rule of the towed barge overestimates the towing force. In order to improve accuracy, the calm water resistance was calculated using ITTC 1978 method which considers wave resistance by the Rankine source method. The added resistance in waves was calculated using the modified radiated energy method which considers the shortwave correction method of NMRI. The performance of the towing resistances through the calm water resistance and the added resistance in waves was compared to rules associated with towed barges.

• Journal of the Society of Naval Architects of Korea
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• v.54 no.1
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• pp.1-9
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• 2017

LNG has significant advantages in regard to environmental aspects comparing with conventional fuel oil. In fact, it is estimated that NOx and SOx emission can be reduced by about 90% and 100%, respectively in case of using LNG as a fuel. LNG-fuelled ship has been considered to be the best option both from an environmental and an economic point of view. Along with these trends, some major shipyards and Classification Societies have started to carry out the risk-based system design for LNG-fuelled ship such as passenger ship, platform supply vessel and large container vessel etc. However, new conceptual gas fuelled ship has high risk level compared with vessel using traditional crude oil especially in view of gas explosion accident. Therefore safety area where installed fuel gas supply system is required risk based system design with special considerations. On this paper, the entire process necessary for the quantitative risk analysis was explained to meet the satisfactory safety level of gas fuelled ship.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.1
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• pp.135-144
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• 2021

In this study, we investigated the characteristics of the process of hydrogen production using boil-of gas (BOG) generated from an LNG-fueled ship and the application of hydrogen fuel cell systems as auxiliary engines. In this study, the BOG steam reformer process was designed using the UniSim R410 program, and the reformer outlet temperature, pressure, and the fraction and consumption of the product according to the steam/carbon ratio (SCR) were calculated. According to the study, the conversion rate of methane was 100 % when the temperature of the reformer was 890 ℃, and maximum hydrogen production was observed. In addition, the lower the pressure, the higher is the reaction activity. However, higher temperatures have led to a decrease in hydrogen production owing to the preponderance of adverse reactions and increased amounts of water and carbon dioxide. As SCR increased, hydrogen production increased, but the required energy consumption also increased proportionally. Although the hydrogen fraction was the highest when the SCR was 1.8, it was confirmed that the optimal operation range was for SCR to operate at 3 to prevent cocking. In addition, the lower the pressure, the higher is the amount of carbon dioxide generated. Furthermore, 42.5 % of the LNG cold energy based on carbon dioxide generation was required for cooling and liquefaction.

• Journal of the Society of Naval Architects of Korea
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• v.51 no.6
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• pp.451-458
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• 2014

The purpose of this study is to compare the economics between a diesel propulsion vessel and a LNG fuel propulsion vessel through the analysis of the present value using the LCC(Life Cycle Cost) method. This study is also to judge the economics for long-term operation of a LNG fuel propulsion vessel as a result of analysis about the equivalent uniform annual cost. In particular, LCC method was strengthened by sensitivity analysis based on combined interest rate which is considering discount rate and inflation rate simultaneously.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.6
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• pp.914-921
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• 2022

The International Maritime Organization (IMO) has set a goal of reducing ship's carbon dioxide emissions by 70% and greenhouse gas emissions by 50% by 2050 compared to 2008. Shipowners and shipyards are promoting various R&D activities such as LNG propulsion, ammonia propulsion, electric propulsion, CO₂ capture, and shaft generators as a way to satisfy this problem. The dual shaft generator has the advantage that it can be directly applied to an existing ship through remodeling. In this paper, the total fuel reduction rate that can be obtained by applying the shaft generator to the existing ship was verified through simulation. For this purpose, the size of the medium-sized ship was defined, and the governor, diesel engine, propeller, torque switch, generator for shaft generator, propulsion motor for shaft generator, and ship model were modeled and simulated.

• Journal of Power System Engineering
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• v.21 no.4
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• pp.70-76
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• 2017

This paper presents the development of a Gas Valve Train (GVT) control system which is the core equipment of LNG fueled vessels. Due to the increasing worldwide demand for echo friendly green ship products, domestic companies urgently require to develop a core equipments for the LNG fueled vessels to secure worldwide markets in marine engineering. A LNG fueled engine generally equips the GVT, a fuel supply system that steadily supplies clean high-pressure LNG to the engine. The GVT requires a safety operational control system that can prevent any gas leakage accident, and a system that monitors operation status in real time. Therefore, we introduces a development for GVT control and monitoring system design and the design was systematically performed by means of functional analysis and differentiation of foreign advanced products.

• Journal of Navigation and Port Research
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• v.44 no.3
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• pp.145-150
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• 2020

The ship motion of large LNG ships affects ships' safety. The purpose of this study was to estimate the transfer function of roll motion among the hull motion of 153,000 m3 class LNG vessels. The ship motion transfer function was modeled using a Linear Time-Invarient system with single input, single output, and transfer function. The transfer function of the ship motion was estimated by the system identification method using single ocean wave as input of the model, and using the roll motion of the LNG ship obtained through ANSYS as the output of the model. The usefulness of the experimental results was evaluated using the precision and estimation rate of the model for cases wherein the different transfer function dimensions. Results of the experiment showed a precision at 99% and 98%, with estimation rate at 78% and 50%. From these results, we found the proposed method of estimating the transfer function of ship motion in this study reasonable. In the future, data of ship motion in actual sea conditions will be acquired and it will be applied to make the construction of models with multiple inputs and multiple outputs for practical use.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.6
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• pp.504-511
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• 2012

The objective of this study is to investigate tank container to be used as fuel tank for LNG fueled ship. Feasibility of tank container to the fuel tank of LNG fueled ship is addressed and the advantage of tank container as fuel tank of ship is investigated. Conceptual configuration of the tank container is designed as well as structural analyses based on finite element method are carried out to meet the design regulation suggested by shipping register. Static loading is considered by structural analysis and impact test is performed. It is necessary to require SRS(shock response spectrum) in order to investigate structural safety which can meet.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.56-58
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• 2019

미세먼지 등 대기오염에 대한 국민적 관심 증가로 정부에서는 2022년까지 국내 배출량 30% 감축을 목표로 하는 '미세먼지 관리 종합대책'을 수립(2017년)하였으며, 국제해사기구(IMO)는 선박의 대기오염물질 배출량 감소를 위한 규정을 강화는 등 대기오염물질 감축을 위한 다양한 노력이 추진되고 있다. 그러나, 부산항을 포함한 부산지역의 미세먼지 농도는 선진국 및 WHO 기준에 비해 여전히 2~3배 높은 수준으로 부산의 주요산업인 부산항을 관리 운영하는 주체인 부산항만공사는 '부산항 미세먼지 종합대책'을 수립하여 추진하고 있다. 본 논문에서는 부산항 내 운영 중인 항만 내 대기오염측정소 데이터를 포함한 항만 인근지역과 타항만의 미세먼지 농도를 분석하였으며, 부산항만공사에서 추진한 항만 하역장비 대기오염물질 배출량 조사결과와 '야드트랙터 LNG 연료전환사업', 'AMP설비 설치사업' 등 '부산항 미세먼지 종합대책'과 그 성과를 소개하고 있다.

• Information and Communications Magazine
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• v.25 no.11
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• pp.29-35
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• 2008

조선 IT기반 융합산업은 차세대 신산업의 발원지로서 막대한 가치창출이 기대되는 블루오션 산업이며, 한국의 최대 강점인 IT/통신 기술과 세계1위인 조선 산업의 융합을 통하여 최고의 부가가치 산업으로 업그레이드가 가능하게 된다. 현재 글로벌 조선 산업은 고부가 가치 선박인 크루저/레저선과 LNG선과 같은 청정에너지 운반선, 선박과 물동량증가에 따른 대형 SuperSeaCat 선박의 출현으로 인해 기존 기계 조선 기술분야에 첨단 IT 융합기술의 접목이 절실히 요구되고 있다. 이에 본고에서는 선박통신 네트워크 기술개발 및 표준화, e-Navigation 추진방향, IT-선박 융합부품 기술개발 등에 대해 살펴보고 IT-조선 융합화 현황을 분석하여 비전과 목표제시를 통해 추진방향을 제시하고자 한다.