• The Journal of Bigdata
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• v.8 no.2
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• pp.165-175
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• 2023

LNG is a representative imported cargo at Incheon Port and has a relatively high contribution to the increase/decrease in overall cargo volume at Incheon Port. In addition, in the view point of nationwide, LNG is the one of the most important key resource to supply the gas and generate electricity. Thus, it is very essential to identify the factors that have impact on the demand fluctuation and build the appropriate forecasting model, which present the basic information to make balance between supply and demand of LNG and establish the plan for power generation. In this study, different to previous research based on macroscopic annual data, the weekly demand of LNG is converted from the cargo volume unloaded by LNG carriers. We have identified the periodicity and correlations among internal and external factors of demand variability. We have identified the input factors for predicting the LNG demand such as seasonality of weekly cargo volume, the peak power demand, and the reserved capacity of power supply. In addition, in order to predict LNG demand, considering the characteristics of the data, time series prediction with weekly LNG cargo volume as a dependent variable and prediction through an artificial neural network model were made, the suitability of the predictions was verified, and the optimal model was established through error comparison between performance and estimates.

• Journal of Ocean Engineering and Technology
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• v.31 no.5
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• pp.357-363
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• 2017

The sloshing pressure acting on a membrane-type LNG CCS is a typical irregular impact load, and the structural response of a tank system induced by sloshing also shows very complex behavior, including fluid structure interaction. Therefore, it is not easy to accurately estimate the sloshing impact pressures and resulting structural response. Moreover, a huge time consuming process to deal with the enormous pressure data obtained during a model tank test and the following structural analysis would be inevitable. To reduce the computation time for structural analysis, in this study, a rational structural modeling strategy was considered, and a simplified scheme to analyze the dynamic structural responses of an LNG CCS was introduced, which was based on the concept of the linear combination of the triangular response functions obtained by a transient response analysis of structures under unit triangular impact pressure. A structural analysis of a real Mark III membrane type insulation system under the sloshing impact pressure time histories obtained by model tests was performed using the various proposed structural models and simplified analysis scheme. The results were investigated in detail, including the elastic support effects of the hull structure.

• Journal of Ocean Engineering and Technology
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• v.28 no.2
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• pp.126-132
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• 2014

In this study, a method for analyzing the collision and interaction between ice bergy bits and a Mark III type liquid natural gas (LNG) carrier was considered, and the structural safety of a ship's hull and cargo containment system (CCS) was evaluated. In the analysis, a constitutive model implementing the strain rate dependant mechanical property was used to consider the typical material characteristics of ice rationally. A relatively simple and easy ice structure interaction analysis procedure, compared with the accurate but complicated FSI analysis scheme, was suggested. When the ice bergy bits collided with ship's side hull under the four assumed scenarios, the structural behaviors of the ship structure and LNG CCS were simulated by applying the suggested ice collision analysis procedure using the commercial hydro-code LS-DYNA. In addition, the effects of the shapes and colliding speed of the ice bergy bits on the ice-structure interaction and safety of the CCS were examined in detail.

• Journal of the Society of Naval Architects of Korea
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• v.54 no.5
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• pp.393-405
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• 2017

This paper deals with the buckling strength of the skirt structure in the spherical LNG carriers. The spherical cargo tank systems consist of spherical tank, skirt, tank cover, pump tower, etc. The skirt supports the spherical cargo tank and is connected with ship hull structure. It is designed to act as a thermal brake between the tank and the hull structure by reducing the thermal conduction from the tank to the supporting structure. It is built up of three parts, upper aluminum part, middle stainless steel part and lower carbon steel part. The 150K spherical LNG carrier was designed and carried out the strength verification under Classification Societies Rule. The design loads due to acceleration, thermal distribution, self-weight and cargo weight were estimated considering requirements of the Class Rule and numerical simulation analyses. Based on the obtained design loads and experienced project data, the initial structure scantling was carried out. To verify the structural integrity, theoretical and numerical analyses were carried out and strength was evaluated aspect of buckling capacity. The results by LR and DNV design code are shown and discussed.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.2
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• pp.233-241
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• 2010

Scaffolding system in the membrane LNG carrier is a steel structure composed of various pipe-shaped members connected by specific coupling devices. In this study, the automatic design program for scaffolding system in membrane LNG carrier has been developed. It enables user to arrange members easily considering design constraints and input variables such as size of tank, position of legs, level height and so on. In addition to that, it creates finite element analysis model with loading and boundary conditions automatically and carries out structural analysis. With post processor based a state-of-the-art computer graphics, users can easily check the results of structural analysis and make a report for structural safety of scaffolding system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.103-108
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• 2020

Generally, the cargo tank of LPG carriers corresponds to an independent tank Type A defined by the International Maritime Organization (IMO). The outside of the tank is insulated by polyurethane foam, and the tank is made of expensive low temperature steel that can withstand temperatures as low as -50℃. The cargo tank is composed of outer shell plates, bulkheads, stiffeners, web frames, and stringers. Among them, the outer shell plates, bulkheads, and stiffeners can be designed without structural analysis by the Classification Rules and are constructed easily through optimal design. On the other hand, optimal design, including numerous structural analysis, is not performed because web frames and stringers should be designed and approved through structural analysis. Only adequate design, which determines the design dimensions through several dozen structural analysis, is performed. In this study, for finite element analysis, eight loading conditions were applied, and the deformation of the entire ship for each loading condition was considered. The minimum weight design was performed for the web frames of cargo tanks in the 82,000 ㎥ LNG carrier through the gradient-based optimization technique, and the weight was reduced by approximately 108 tons per ship.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.06a
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• pp.379-381
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• 2011

2010년 3월 22일 "Ice Navigation"에 대한 경험과 자료 수집을 위하여 통영항(평택항)과 Sakhalin "Prigorodnoye항"을 운항하는 대한해운 소속의 "K. Jasmine"호를 승선하여 "Prigorodnoye항"에서 LNG $143,700M^3$를 선적하여 "통영항"에서 양하하는 과정을 경험하고 하선하였다. "K. Jasmine"호는 년 150만톤의 LNG 수입을 위한 "한국 ${\leftrightarrow}$ Sakhalin Project"에 투입된 LNG운반선으로서 "Russian Maritime Register of Shipping"의 "Ice Class LU2" 증서를 갖고 있는 선박이다. 이 증서는 선박이 60Cm 두께의 얼음 해역에서 Ice Breaker의 인도 아래 4Knots 이상의 선속을 유지할 수 있음을 보장받고 있다. 운항중 SEIC(Sakhalin Energy Investment Company)에서는 Ice map을 매일 제공하는 하고 있었으며, 이를 참조하여 본선에서는 계획된 항해를 수행하였다. 이 논문에서는 Ice Navigation선박의 성능 조건에 대하여 검토하여 향후 이 항로에 취항하는 선박에 지침이 되고자 한다.

• The Safety technology
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• no.182
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• pp.19-21
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• 2013

우리나라 경제발전 역사에서 제철, 조선, 기계제조업 등의 중공업은 따로 떼어 놓고 생각할 수 없을 정도로 막대한 영향을 미쳤다. 중공업이 발전하면서 다른 여타 산업의 기반이 조성된 것은 물론이고, 중공업 제품들이 수출의 일등 공신 역할을 하면서 경제성장에 크게 이바지한 것이다. 이처럼 남다른 위치에 있는 중공업 기업 가운데 특히 눈에 띄는 회사가 있다. 바로 46회에 이어 47회 무역의 날에서 '2천만 불 수출탑'을 달성한 HSG 중공업(주)이 그곳이다. 지난 1989년 금광기업사로 출범한 이곳은 LNG 운반선의 펌프타워를 비롯한 대형 조선기자재와 해양플랜트, 하역운반설비 등을 전문적으로 제작하는 기업이다. 그 명성에 걸맞게 HSG 중공업(주)에서는 자재 구매에서부터 설계, 제작까지 모든 공정이 이뤄지고 있다. 단순하게 제품만을 생산하고 있다고 판단하면 큰 오산이다. 이곳은 삼성중공업, 현대중공업, 대우조선해양 등 국내 유수의 기업은 물론 샌드빅, 지멘스 등 외국기업으로부터 많은 물량을 수주받고 있을 정도로 기술력과 품질 모두를 인정받고 있다. 그렇다면 무엇이 이처럼 회사를 성장 발전시켜나갔을까. 이곳 관계자들은 이 같은 물음의 답으로 하나같이 '안전'을 꼽고 있다. 근로자들의 안전을 위해 매진한 것이 곧 고품질의 제품을 생산해 낼 수 있는 밑거름이 됐다는 것이다. 무재해 일터를 구축하기 위해 빈틈없는 안전관리를 전개해 나가고 있는 HSG 중공업(주)을 찾아가봤다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.2
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• pp.143-148
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• 2011

Daesan Harbor is developing under the Industrial Complex or Petrochemistry Development Plan making the port the main hub-port in the West coast. Because of this development. the traffic volume is expected to increase to 9,1.95 incoming vessels by 2020, an increase of 167% compared to 2008 figure. This study thoroughly analyzes and evaluates a systematic and comprehensive use of the fairway in the Daesan Harbor. It establishes a future oriented and safe marine transportation environment upon appropriate examination of the total fairways and sailing assistance facilities.

• Journal of the Society of Naval Architects of Korea
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• v.50 no.2
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• pp.120-128
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• 2013

This paper presents the results of sloshing experiments having different fluids in model tanks with various density ratios. The experimental model consisting water and air at ambient, which has been commonly used, is not consistent in density ratio with that of an actual LNG cargo tank. Therefore, an advanced experimental scheme is developed to consider the same density ratio of LNG and NG by using a mixed gas of sulfur hexafluoride ($SF_6$) and nitrogen ($N_2$). For experimental observation, a two-dimensional model tank of 1/40 scale and a three-dimensional model tank of 1/50 scale have been manufactured and tested at various conditions. Two different fillings with various excitation frequencies under regular motions have been considered for the two-dimensional model tank, and three different filling levels under irregular motions have been imposed for the three-dimensional model tank. The density ratio between gas and liquid varies from the ratio of the ambient air and water to that of the actual LNG cargo container, and the different composition of gas is used for this variation. Based on the present experimental results, it is found that the decrease of sloshing pressure is predicted when the density ratio increases.