• 한국해양공학회지
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• 제29권6호
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• pp.418-426
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• 2015

Recently, shipping operators have been making efforts to reduce the fuel cost in various ways, such as trim optimization and bulb re-design. Furthermore, IMO restricts the hydro-dioxide emissions to the environment based on the EEDI (Energy Efficiency Design Index), EEOI (Energy Efficiency Operational Indicator), and SEEMP (Ship Energy Efficiency Management Plan). In particular, ship speed is one of the most important factors for calculating the EEDI, which is based on methods suggested by ITTC (International Towing Tank Conference) or ISO (International Standardization Organization). Many shipbuilding companies in Korea have carried out speed trials around the Korea Straits. However, the conditions for these speed trials have not been exactly the same as those for model tests. Therefore, a ship’s speed is corrected by measured environmental data such as the seawater temperature, density, wind, waves, swell, drift, and rudder angle to match the conditions of the model tests. In this study, fundamental research was performed to evaluate the ship resistance performance due to changes in the water temperature and salinity, comparing the ISO method and numerical simulation. A numerical simulation of a KCS (KRISO Container ship) with a free-surface was performed using the commercial software Star-CCM+ under three conditions that were assumed based on the water temperature and salinity data in the Korea Straits. In the simulation results, the resistance increased under low water temperature & high salinity conditions, and it decreased under high water temperature & low salinity conditions. In addition, the ISO method showed the same result as the simulation.

• 대한조선학회논문집
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• 제53권1호
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• pp.18-28
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• 2016

In shipbuilding, the scheduling system is susceptible to sudden changes and thus it turns to be difficult to predict the differences between schedule and production records in advance. A computer-based simulation is commonly utilized to overcome the discrepancies occurred in estimating workloads and resulting processing times. The main drawback of this simulation-based solution is its limited applicability because, in most cases, each shipyard requires specific and customized simulation environment. By standardizing the planning data of the midterm scheduling system, as proposed in this paper, the efficiency of the current simulation model can be enhanced. To present an alternative approach, this paper begins with the analysis of the complex planning data structure of several shipyards and then proceeds to construct a standard data structure based on the neutral format. An interface application is developed for the data transaction and simulation in on-line environment. As a result, a simulation-based production management of shipyards can be achieved by the efficient prediction of planning and scheduling.

• 한국정보통신학회논문지
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• 제17권8호
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• pp.1761-1768
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• 2013

디지털 선박 생산기술은 조선소에서 필연적으로 발생하는 재계획 및 재작업에 따른 비용과 시간을 절감할 수 있는 기술이다 이 기술을 효율적으로 적용하기 위해서는 적용 가능한 . 분야에 대한 전략수립이 반드시 이루어져야 한다. 본 논문에서는 조선소 생산계획 업무 프로세스를 분석하여 디지털 선박생산 기술을 적용하기 위한 전략을 수립하는 것을 목표로 한다. BPR방법론을 기반으로 현행 생산계획 업무프로세스를 분석하고, 워크플로우를 모델링하여 병목프로세스를 도출한다. 도출된 병목프로세스를 심도있게 분석하여 핵심개선기회 다이어그램을 작성하고, 프로세스시뮬레이션을 수행하여 적용시나리오 생성뿐만 아니라 기대효과도 산출한다. 디지털 선박생산기술의 적용전략은 조선소에서 양질의 제품에 필요한 건조 비용 및 시간을 줄일 수 있는 밑그림을 제공할 것으로 사료된다.

• 한국시뮬레이션학회논문지
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• 제21권1호
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• pp.1-8
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• 2012

최근들어, 글로벌 조선소들은 친환경 선박 건조와 환경 친화적 생산 공정에 큰 관심을 보이고 있다. 이러한 추세에 따라 이 연구는 조선소 레이아웃에 전 과정 평가를 적용하는 연구를 수행하였다. 전 과정 평가는 제품과 시스템의 전수명주기와 관련된 환경적 영향을 평가하는 기법으로 특정 산업분야에서 ISO 14040 표준에 따라 적용연구가 수행되고 있다. 전 과정 평가를 조선소 레이아웃에 적용하기 위해 조선소 레이아웃 계획 프레임워크를 분석하고, 조선소 레이아웃에 대한 목록분석을 수행하였으며, 환경적 영향에 대한 이산 사건 시뮬레이션 모델을 구축하였다.

• 한국CDE학회논문집
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• 제21권2호
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• pp.204-214
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• 2016

Shipbuilding process takes a long time for producing final products, and needs many different resources. Because of these characteristics, it has been studied about shipyard simulation and virtual manufacturing that is able to implement the virtual manufacturing process. However, among the previous researches, it requires considerable time and effort to construct simulation model since the systematic methodology has not been used for simulation modeling. Also, reusability of constructed simulation model was low. Therefore, this research defines the method to construct shipyard simulation system using the process-centric simulation modeling methodology and shipyard simulation framework. This paper also validates the utility of this methodology through applying to construct simulation model for the shipyard master plan validation.

• Journal of Ship and Ocean Technology
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• 제8권1호
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• pp.42-50
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• 2004

In these ten years, the cavitation and erosion phenomena in the rudder have been increased for high-speed container ships. The cavitation in the rudder blades which is injurious to rudder efficiency is mainly caused by the main flow with a large angle of attack induced by propellers, and the erosion which occurs as a result of repeated blows by shock wave that cavitation collapse may produce was observed in the gap legion of the rudder. However, gap cavitation is not prone to occur in model experiments because of low Reynolds number. So, the viscous effect should be considered for solving the flow of the narrow gap. In order to predict the cavitation phenomena and to improve the performance of the rudder, the analysis of the viscous flow in the rudder gap is positively necessary. In this study, numerical calculation for the solution of the RANS equation is applied to the two-dimensional flow around the rudder gap including horn part and pintle part. The velocity and pressure field are numerically acquired according to Reynolds number and the case that the round bar is installed in the gap is analyzed. For reduced the acceleration that pressure drop can be highly restrained numerically and in model experiment, the cavitation bubbles can be reduced.

• Journal of Advanced Research in Ocean Engineering
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• 제2권4호
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• pp.179-191
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• 2016

As the demand for renewable energy has increased following the worldwide agreement to act against global climate change and disaster, large-scale floating offshore wind systems have become a more viable solution. However, the cost of the whole system is still too high for practical realization. To make the cost of a floating wind system be more economical, a new concept of tension leg platform (TLP) type ocean floating wind system has been developed. To verify the performance of a 5-MW TLP type ocean floating wind power system designed by the Korea Advanced Institute of Science and Technology, the FAST simulation developed by the National Renewable Energy Laboratory is used. Further, 1/50 scale model tests have been carried out in the ocean engineering tank of the Research Institute of Medium and Small Shipbuilding, Korea. This paper compares the simulation and ocean engineering tank test results on motion prediction and tension assessment of the TLP anchor.

• 한국CDE학회논문집
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• 제17권2호
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• pp.111-122
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• 2012

Capacity planning plays an important role not only for master production plan but also for facility or layout design in shipbuilding. Product work breakdown structure, attributes of production resources, and production method or process data are associated in order to make the discrete event simulation model of shipyard layout plan. The production amount of each process and the process time is assumed to be stochastic. Based on the stochastic discrete event simulation model, the production capacity of each facility in shipyard is estimated. The stochastic model of product arrival time, process time and transferring time is introduced for each process. Also, the production capacity is estimated for the assumed master production schedule.

• International Journal of Naval Architecture and Ocean Engineering
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• 제8권4호
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• pp.398-408
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• 2016

Based on non-completely hybrid flow line scheduling of panel block in shipbuilding, several uncertain factors influencing the problem were analyzed in a real environment, and a nonlinear integer programming model was built for each sub-scheduling problem. To narrow the difference between theory and application, rolling horizon and rescheduling methods are proposed. Moreover, with respect to the uncertainty of processing time, arriving time and due time, we take the minimizing of the early and delayed delivery costs as the objective, and establish an evaluation with a global penalty function. Finally, numerical experiments and a simulation analysis were undertaken to demonstrate the effectiveness of the model and algorithm.

• 한국CDE학회논문집
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• 제10권3호
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• pp.210-216
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• 2005

Digital manufacturing could be very effective in shipbuilding in order to estimate the process time, to improve the operation efficiency, and to prevent bottleneck processes in advance. The subassembly process having done research consists of piece arrangement, tack welding, robot welding, manual welding and so on. The robot welding of them was the focus of the simulation. The analysis and modeling were carried out by using UML (Unified Modeling Language) as well as $IDEF\phi$ (Integration DEFinition). The characteristics of the process resources were analyzed using the shipyard data, and the layout of the subassembly line was designed with the resources. Using the constructed resource and process model, the productivity and efficiency of changed robot welding stage were investigated. It was simulated how much the variations in the resource performance have influence on improvement of productivity. One of the important outputs in this simulation was the cycle time during a certain period's work. The cycle time prediction was also undertaken for the different torch and the different piece arrangement. The proposed model was established three-dimensionally in a digital environment so that interferences among objects and space allocations for the resources could be easily investigated.