• Journal of the Korean Society of Marine Environment & Safety
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• v.11 no.1 s.22
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• pp.39-45
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• 2005

Recently, RFID technology play a key role to implement ubiquitous sensor network(USN). In this paper, we introduce trends of RFID technology, standardization, and then its applications. The purpose of this work is to suggest prosperous applications of RFID, which is applicable on marine information system, such as ship inventory management, management of container and its contents, sensing of environments within cargo hold, management of fishery boats. In case that RFID technology is utilized on marine information systems, it makes safety at sea and marine environments protection.

• Special Issue of the Society of Naval Architects of Korea
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• 2005.06a
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• pp.22-30
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• 2005

Sloshing loads, produced by the violent liquid free-surface motions inside the cargo tank have become an important design parameter in ship building industry since there have been demands for the increased sizes of the cargo containment system of LNG carriers. In this study, sloshing impact pressure acting on the shell of the spherical cargo tank of an LNG carrier as well as dynamic pressure and flow behavior around the pump tower located at the center of the tank have been calculated. Comparative numerical sloshing simulations for a spherical LNG tank using 2-D LR.FLUIDS which is based on the finite difference method and 3-D MSC.DYTRAN which is capable of calculating nonlinear fluid-structure interaction have been carried out. A method of calculating sloshing-induced dynamic loads and the subsequent structural strength analysis for pump tower of a spherical LNG carrier using MSC. DYTRAN and MSC.NASTRAN have been presented.

• Special Issue of the Society of Naval Architects of Korea
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• 2005.06a
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• pp.63-68
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• 2005

Optimum design of the big brackets is performed through iterated 3-D FE analyses to meet the permissible limits of stress, which consumes an excessive amount of calculation time. Therefore, this study has been prepared to determine rapidly and accurately an optimum size and scantling of the big brackets at the initial design stage. The generalized slope deflection method (GSDM) based on the span point concept is applied to enhance the efficiency of iterated structural analyses. The accuracy and applicability of the present method is verified by comparing with a detail 3-D FE analysis of web frame structures. As an optimization technique, evolution strategies (ES) are applied using discrete design variables for practical design.

• Journal of computational fluids engineering
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• v.14 no.2
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• pp.9-18
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• 2009

The cargo containment system (CCS) for ships carrying cryogenic fluid consists of at least two levels of barriers and insulation layers. It is because, even though there is a small amount of leak through the primary barrier, the liquid tight secondary barrier blocks further leakage of the cryogenic fluid. However, once the secondary barrier is damaged, it is highly possible that the leaked cryogenic fluid flows through the flat joint made of glass wool and reaches the inner hull of the ship. The primary objective of the present study is to investigate the influence of the damage extent in the secondary barrier on the amount of leaked cryogenic fluid reaching the inner hull and the temperature distribution there. Simulation results using a computational fluid dynamics tool were compared with the experimental data for the leaked cryogenic fluid flow and evaporation in the secondary insulation layer. The experimental and computational results suggest that, unless there is a massive leak, the cryogenic fluid mostly evaporates in the insulation layer and does not reach the inner hull in the state of liquid.

• Journal of Korean Society of Transportation
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• v.22 no.6
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• pp.219-226
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• 2004

본 연구는 지속적인 여객 및 화물량의 증가로 기존 수송수단이 포화에 이른 실정에 새로운 교통수단으로 추진한 고속철도 사업에 대해, 고속철도 개통 후 단기간에 드러난 이용현황 및 문제점을 도출해 기선방안을 제시하고자 한다. 이를 위해 관련 단체 및 기관의 자료를 수집 분석하였으며, 설문조사를 수행하여 결과를 도출하였다. 또한 광범 위한 고속철도 사업의 특성아래 여객 부문에 대한 대중교통 측면으로 연구의 범위를 한정하였다. 고속철도 개통 후, 여객 및 화물 수송의 형태에는 단기간이나마 큰 변화가 있는 것으로 나타났으나 그에 반해 고속철도의 이용에 있어서 주목할 만한 문제점 또한 조사되었다. 주요 사항으로는 역방향 유해성, 일반열차로의 불편전이, 터널통과시의 소음 등으로서 이는 개통 초기 고속철도에 대한 그릇된 대국민 인식을 가져오게 함과 동시에 향후 개인들간 교통수단 선택에 있어서까지 그릇된 영향을 끼칠 수 있다. 현재 각각의 문제점에 대한 개선방안으로 일반열차 확대 및 할인혜택, 점진적인 순방향 좌석으로서 교체 및 소음 저감방안을 위한 연구 용역 등이 실행되거나 준비되고 있으나 그에 대한 뚜렷한 개선 징후는 아직 미미한 상태로 분석되고 있다. 본 연구에서 실시한 설문조사 결과 아직까지는 고속철도에 대한 인식이 긍정적인 수준을 보이고 있으나 개별 문제점에 대한 좀더 깊은 고찰과 개선안 제시가 이루어진다면 향후 고속철도에 대한 대국민 인식을 한 단계 더 높여, 그 이용을 활성화 시킬 수 있는 좋은 기회가 될 것으로 판단된다.

• Journal of Korean Society of Transportation
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• v.23 no.6 s.84
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• pp.31-40
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• 2005

Main airports in the Intra-Asian market have faced competition not only to attract China-bound transshipment cargoes but also to be hub airport in same region. In spite of such a importance, the previous research has been short of evaluation of airport competitiveness. Implication of the previous research has mainly been focused on evaluation of airport critical factor service qualify and efficiency. The aim of this paper is to present critical points that affect airport competitiveness using an algorithm based on reversed fuzzy evaluation and senario method. The results of senario analysis and reversed fuzzy evaluation shows that Incheon international airport needs to enhance service level of 7% as a result of senario analysis and service level of 5% and brand equity level of 10% at the same time as a result of reversed fuzzy evaluation analysis, to ensure competitiveness in same region.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.473-478
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• 2008

In this experimental, selective catalytic reduction (SCR) of NO with NH3 over manganese sulfates and manganese sulfates was investigated with catalytic activity, kinetics, temperature programmed reduction (TPR) and TGA. Manganese oxides showed high catalytic activity for SCR at temperature below $200^{\circ}C$. In case of manganese sulfates, the temperature at which SCR of nitric oxide appears shifted to high temperature with sulfation degree, and the maximum catalytic efficiency decreased. The temperature of the onset of reduction for manganese oxides and manganese sulfates is about $160^{\circ}C$ and over $280^{\circ}C$, respectively. We suggest that the onset of reduction in TPR correlates with the onset of SCR activity. Because the pre-exponential factor of manganese sulfates is lower as 1/1000 times than that of other catalysts, catalytic activity of manganese sulfates for NO showed low. The reduction temperature of natural manganese ore which consists of various metal oxides showed lower than that of pure manganese oxides.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.8
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• pp.843-848
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• 2013

As the LNG demands are growing, the constructions of LNG FPSO (Floating Production Storage and Off-loading) and LNG carriers have been constantly increased, and the various design of storage tank has been tried. This paper propose that the material of inner storage tanks is made of 5~9% Ni steel plate and perlite powder insulation instead of urethane foam block. It needs essentially to obtain the proper design specifications that are the pressure of perlite, the characteristics of resilient blanket as the pressure absorber, optimum thickness of blanket and design pressure of tank wall, etc. to enable the perlite insulation system to LNG carrier, The results show that the design thickness of blanket should be between 1/4 to 1/3 of insulation width and the optimum rate becomes 30%, and the design pressure be applied below 1,500 Pa with blanket thickness.

• Journal of the Society of Naval Architects of Korea
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• v.58 no.2
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• pp.66-72
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• 2021

As the demand for natural gas that satisfies environmental regulations increases, the quantities of natural gas cargo that carrier can load is also increasing. Natural gas is transported in a liquefied state at -163 ℃ to increase loading efficiency. Among several LNG CCS types, MARK-III types are generally adopted in terms of loading efficiency. The secondary barrier adhesives of the MARK-III, nevertheless, is subjected to tensile stress due to thermal contraction and tension in the environment. In terms of these reasons, local analysis of the adhesive to evaluate the stress state must be carried out. According to previous studies, local analysis is unavailable since material properties for secondary barrier adhesives have not been reported. Thus, in this study, the cryogenic tensile test and coefficient of thermal expansion of epoxy and polyurethane (PU15, PU45), which are most widely used at cryogenic temperatures, were experimentally analyzed. At cryogenic temperature, the mechanical behavior of the polyurethane adhesive was better than epoxy of the adhesive. the joint of FSB and epoxy adhesive of the secondary barrier has the maximum coefficient of thermal expansion difference at 25 ℃ and minimum at -150 ℃, respectively.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.4
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• pp.213-221
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• 2023

The demand for Liquefied Natural Gas (LNG) carriers and LNG-fueled ships has significantly increased in recent years due to the sulfur-oxide emission regulations by the International Maritime Organization (IMO). The main goal of this paper is to introduce the process for the Engineering Critical Assessment (ECA) of IMO independent type-B cargo tanks made from 9% nickel alloy. A methodology proposed by the British Standard was used to conduct ECA for any structure with initial flaws. Based on this standard, a Matlab code was developed to perform ECA. Coarse mesh Finite Element Analysis (FEA) was performed on an independent type-B LNG cargo tank with a capacity of 15,000 m³. The location with the highest development of maximum principal stress was identified at the bottom of the cargo tank. Fine mesh FEA was performed to obtain the stress range required for ECA. The dynamic cargo tank loads used for FEA were determined using some ship rules presented by Det Norske Veritas. As a result of performing a 20-year long-term crack propagation analysis with a semi-elliptical surface crack, the fracture-to-yield ratio exceeded the Fracture Assessment Line (FAL) and some structural reinforcement was necessary. Performing a 15-day short-term crack propagation analysis, the fracture-to-yield ratio remained within the FAL, and no significant LNG leaks were expected. This paper is believed to provide a guide for performing ECA of LNG cargo tanks in the future by providing the basic theory and application sample necessary to perform ECA.