• 해양환경안전학회지
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• 제25권1호
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• pp.122-129
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• 2019

신조 방식의 제조업의 특성상 경기 사이클이 존재하기 때문에, 장기적으로 이를 대처할 동반 산업이 절실하게 필요로 하고 있다. 이러한 요구에 적합한 분야가 수리조선업 분야이다. 수리조선업을 운영하기 위해서는 플로팅도크가 필수적으로 필요로 하며, 대부분 노후화된 플로팅도크를 해외로부터 수입한 후, 개/보수를 통하여 운용하고 있다. 그러나, 사용연한이 최소 30년 이상이고, 운용 시 특정 선급에 입급을 시키지 않기 때문에, 안전성에 대한 정확한 지침은 전무한 상태이다. 본 연구에서는 노후화된 플로팅도크의 계측한 두께 정보를 활용하여, 구조강도 검토를 수행하고, 운용중인 플로팅도크의 잔류 구조강도를 분석하였다. 연구를 통하여 도출된 주요 결과들은 유사 설비의 구조 안전성 검토에 대한 가이드라인을 참조할 수 있으며, 개/보수 시 이러한 방법을 활용하면 빠른 시간 내에 최적 해를 찾을 수 있을 것으로 기대된다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제13권1호
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• pp.659-673
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• 2021

This study aims to investigate the impact of the High Pressure Selective Catalytic Reduction system (SCR-HP) on a large marine two-stroke engine performance parameters by employing thermodynamic modelling. A coupled model of the zero-dimensional type is extended to incorporate the modelling of the SCR-HP components and the Control Bypass Valve (CBV) block. This model is employed to simulate several scenarios representing the engine operation at both healthy and degraded conditions considering the compressor fouling and the SCR reactor clogging. The derived results are analysed to quantify the impact of the SCR-HP on the investigated engine performance. The SCR system pressure drop and the cylinder bypass valve flow cause an increase of the engine Specific Fuel Oil Consumption (SFOC) in the range 0.3-2.77 g/kWh. The thermal inertia of the SCR-HP is mainly attributed to the SCR reactor, which causes a delayed turbocharger response. These effects are more pronounced at low engine loads. This study supports the better understanding of the operating characteristics of marine two-stroke diesel engines equipped with the SCR-HP and quantification of the impact of the components degradation on the engine performance.

• 한국항만경제학회지
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• 제34권2호
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• pp.1-16
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• 2018

해양산업은 새로운 부가가치산업 및 신성장동력 산업으로 인식되고 있다. 특히 항만을 중심으로 클러스터를 조성하여 고부가가치를 창출하고 있다. 해외 선진항만들도 앞 다투어 클러스터를 조성하여 수익창출과 경쟁력 강화에 나서고 있다. 우리나라도 2015년 해양산업클러스터 조성과 육성에 관한 법률을 제정하였다. 따라서 각 지역별로 어떤 해양산업이 비교우위에 있는지 파악하는 것은 해양산업클러스터를 통한 집적화 전략을 수립하는데 매우 중요하다. 따라서 본 연구에서는 유류를 중심으로 한 원자재 처리와 함께 컨테이너 처리, 중국과 카페리 항로 개설을 앞두고 있는 충남지역을 대상으로 해양산업 구조를 분석하였다. 먼저 해양산업 분류에 대한 기존 문헌분석을 실시하여 해운 물류업, 조선업, 수산업, 해양관광업, 기타업 5개의 대분류와 21개 중분류, 84개 소분류로 해양산업을 재분류하였다. 재분류한 해양산업을 기준으로 입지계수와 변이할당분석 기법을 활용하여 충남의 해양산업 구조를 분석하였다. 충남지역 해양산업 구조 분석결과, 입지계수 분석에 있어서 수산업이 1.718로 가장 높게 나타났고, 해양관광(1.092), 조선업(0.823), 해운 물류업(0.789)순으로 나타났다. 그리고 변이할당분석을 통해 충남지역 해양산업의 총 성장효과는 36,315명으로 나타났고 국가성장효과를 제외한 순성장효과는 21,321명으로 산정되었다. 이러한 결과를 바탕으로 충남지역 해양산업 중 비교우위, 비교열위에 있는 산업을 분류하였다. 이 연구결과는 향후 충남지역 해양산업클러스터 구축 시 전략수립에 기초자료로 활용할 수 있을 것이다.

• 대한조선학회지
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• 제18권4호
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• pp.31-40
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• 1981

Nowadays we needs the ship design ability strongly for our shipbuilding industry to attain the 2nd position among the competitive world marine industries. But we have short experience in ship design, so several ship design terminologies are used without clear understandings. Here, papers on ship design procedure and design methodology are summarized with some investigation about our present status. In addition, the state arts and new developments of Computer Aided ship Design in advanced ship building countries are treated. It is hoped that we-ship designers of our country-do have common understandings about the ship design terminologies.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 후기학술대회논문집
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• pp.224-225
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• 2005

The lightness of components required on marine and shipbuilding industry is requiring high strength of components. In particular, fatigue failure phenomena, which happen in metal, bring on danger in human life and property. Therefore, antifatigue failure technology takes an important part of current industries. In this study, it was investigated about endurance and fatigue crack propagation rate of according to stress ratio of SMAW commonly using for welding structures in present. Fatigue crack propagation rate(da/dN) of low load(R=0.1) was lower than of high load(R=0.6) for piping weld. And in stage I, ${\Delta}$Kth, the threshold stress intensity factor of the weld under heavy load is higher than under small load. Fatigue life shows more improvement in the weld of stress ratio R=0.l than in the weld of stress ratio R=0.6.

• 한국안전학회지
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• 제23권2호
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• pp.51-56
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• 2008

In these days, work-related musculoskeletal disorders(WMSDs) is one of the issues in the shipbuilding industry. As the number of injured workers and demands for worker's compensation have rapidly increased, improvement of work conditions and environments to prevent WMSDs has been more demanded. To reduce WMSDs' hazards in the shipbuilding industry, simulation technique which showed it's ability of increasing the manufacturing productivity was applied, because simulation technique has the evaluation ability for a worker's danger level of production process by RULA(Rapid Upper Limb Assesment). In this research, worker's altitude had modeled and worker's action has simulated. After the caution level was evaluated, we pointed out clues which had high workload. To reduce work-load, we applied ergonomic principles for improving working conditions and environments. Improved working conditions and environments were simulated using human modelling and simulation and their workload were evaluated again.

• International Journal of Naval Architecture and Ocean Engineering
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• 제13권1호
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• pp.115-125
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• 2021

Simulation-based hull form optimization is a typical HEB (high-dimensional, expensive computationally, black-box) problem. Conventional optimization algorithms easily fall into the "curse of dimensionality" when dealing with HEB problems. A recently proposed Cross-Entropy (CE) optimization algorithm is an advanced stochastic optimization algorithm based on a probability model, which has the potential to deal with high-dimensional optimization problems. Currently, the CE algorithm is still in the theoretical research stage and rarely applied to actual engineering optimization. One reason is that the Monte Carlo (MC) method is used to estimate the high-dimensional integrals in parameter update, leading to a large sample size. This paper proposes an improved CE algorithm based on quasi-Monte Carlo (QMC) estimation using high-dimensional truncated Sobol subsequence, referred to as the QMC-CE algorithm. The optimization performance of the proposed algorithm is better than that of the original CE algorithm. With a set of identical control parameters, the tests on six standard test functions and a hull form optimization problem show that the proposed algorithm not only has faster convergence but can also apply to complex simulation optimization problems.

• 수산해양교육연구
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• 제29권3호
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• pp.822-833
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• 2017

The purpose of this study is to propose a company-centered apprenticeship educational program to secure professional manpower in the ship repair industry. There are various efforts to secure professional manpower across industries. However, it is very rare in the ship repair industry. In this study, we analyzed the educational program implemented by Research Institute of Medium & Small Shipbuilding(RIMS) with considering their problems. We also studied the apprenticeship education for improving a few problems of RIMS's program. As a result, we presented the new educational program by integrating the concept of apprenticeship education into the current educational program with two main points as belows. 1) the necessity of the convergence with a company-centered apprenticeship education. 2) the necessity of a training program with a focus on the global market environment.

• International Journal of Naval Architecture and Ocean Engineering
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• 제7권2호
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• pp.364-374
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• 2015

The purpose of this research is to compare and analyze the advanced speed of ships with different rudder controller in wavy condition by using a simulation. The commercial simulation tool named AQWA is used to develop the simulation of ship which has 3 degree of freedom. The nonlinear hydrodynamic force acting on hull, the propeller thrust and the rudder force are calculated by the additional subroutine which interlock with the commercial simulation tool, and the regular wave is used as the source of the external force for the simulation. Rudder rotational velocity and autopilot coefficients vary to make the different rudder controller. An advanced speed of ships depending on the rudder controller is analyzed after the autopilot simulations.

• Journal of Advanced Marine Engineering and Technology
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• 제39권5호
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• pp.527-535
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• 2015

As a new technical approach, a hydraulic and magnetic clamp device was attempted to realize a magnetic clamp crane system that uses 8 simultaneously actuating individual hydraulic cylinders. Through this approach, a Sr type of ferritic permanent magnet ($SrO{\cdot}6Fe_2O_3$), not the previously employed electro-magnet, was utilized for the purpose of lifting and transporting the heavy weighted and oversized curved steel plates used for manufacturing the ships. This study is aimed at manufacturing and developing the hydraulic magnetic clamp prototype, which is composed of three main parts - the base frame, cylinder joint, and magnet joint - in order to safely transport such curved steel plates. Furthermore, this research was pursued to conduct a performance evaluation as to the prototype manufacture and acquire the planned quantity value and the development purpose items. The most significant item for a performance evaluation was estimated for the magnetic adhesive force (G) and in this process, a ferritic permanent magnet (Sr type) with 3700~4000 G of residual induction (Br) and 2640/2770 Oe of coercive force (Hc) was utilized. In addition, other relevant items such as hoist tension (kN), transportation time (sec), and the applied load (Kgf) exerted on the hydraulic cylinders were also evaluated in order to acquire the optimum quantity value. As a result of the evaluation, the relevant device turned out to be suitable for safely transporting the curved steel plates.