• 대한조선학회논문집
• /
• 제52권3호
• /
• pp.171-179
• /
• 2015

Usually, in case of wind turbines on land, there are a lot of constraints for installation such as the insufficient installation space and noise pollution. On March 11, 2011, a nuclear leakage accident occurred due to the tsunami caused by the earthquake in Japan and then there have been a rapidly growing interest in floating offshore wind turbines. In this study, an optimization of the substructure of a semi-submersible type floating offshore wind turbine was made. Design variables were set and design alternatives were fixed. UOU-FAST was used for motion analysis in combined environmental conditions of waves and wind. Response Amplitude Operators(RAOs) were compared between the design alternatives.

• International Journal of Naval Architecture and Ocean Engineering
• /
• 제7권1호
• /
• pp.115-127
• /
• 2015

The aim of this study is to develop a simplified formula for added mass coefficients of a two-dimensional floating body moving vertically in a finite water depth. Floating bodies with various sectional areas may represent simplified structure sections transformed by Lewis form, and can be used for floating body motion analysis using strip theory or another relevant method. Since the added mass of a floating body varies with wave frequency and water depth, a correction factor is developed to take these effects into account. Using a developed two-dimensional numerical wave tank technique, the reference added masses are calculated for various water depths at high frequency, and used them as basis values to formulate the correction factors. To verify the effectiveness of the developed formulas, the predicted heave added mass coefficients for various wetted body sections and wave frequencies are compared with numerical results from the Numerical Wave Tank (NWT) technique.

• 한국BIM학회 논문집
• /
• 제9권1호
• /
• pp.22-31
• /
• 2019

In this paper, we construct a prototype model for city data prediction by using time series data of floating population, and use machine learning to analyze urban data of complex structure. A correlation prediction model was constructed using three of the 10 data (total flow population, male flow population, and Monday flow population), and the result was compared with the actual data. The results of the accuracy were evaluated. The results of this study show that the predicted model of the floating population predicts the correlation between the predicted floating population and the current state of commerce. It is expected that it will help efficient and objective design in the planning stages of architecture, landscape, and urban areas such as tree environment design and layout of trails. Also, it is expected that the dynamic population prediction using multivariate time series data and collected location data will be able to perform integrated simulation with time series data of various fields.

• 해양환경안전학회지
• /
• 제29권4호
• /
• pp.407-416
• /
• 2023

해양레저활동 인구증가 및 관련 산업의 급성장으로 인해 레저 선박을 접안하는 계류시설과 부유체를 기반으로 하는 해상부유식 펜션 등 레저시설 수요가 증가하고 있으며, 이러한 연안에서 사용되는 부유체는 대부분 경량 부유체로서 중량이 상대적으로 경량이므로 연안으로 유입되는 파(Wave)와 상재 하중에 의해 쉽게 경사가 발생하여 안정성이 낮아 안전사고가 빈번히 발생하고 있다. 이런 문제점에 대한 해결방안으로 부유체의 운동저감장치를 연구하여 알리고자 한다. 본 연구논문에서는 부유체에 운동저감장치(기압차를 이용한 운동저감장치)를 부착하여 운동저감효과를 부착하지 않은 부유체와 비교하는 방식으로 효과를 분석하였다. 효과분석은 전산해석시험으로 분석하여 부유체의 안정성 증가방법을 연구하고 그 효과를 검증해 보았다. 시험결과 분석결과 기압차를 이용한 운동저감장치를 부착한 부유체가 운동저감장치를 부착하지 않은 부유체보다 파랑에 대한 운동량이 저감되어 부유체의 안정성이 증가된 것으로 분석되었다. 이러한 부유체의 운동저감 장치는 무동력 선박뿐만 아니라 동력선, 반잠수식 선박에서도 유용하게 사용될 것으로 판단되어 다양한 분야에 적용하여 연구를 진행할 계획이다.

• 한국해양공학회지
• /
• 제27권3호
• /
• pp.43-52
• /
• 2013

In the present study, a flow analysis for estimating the wave loads acting on a stationary floating body inside a viscous numerical wave tank was performed using the commercial software FLUENT. The governing equations for the viscous and incompressible fluid motion were the continuity and Navier-Stokes equations, and a piston-type wavemaker was employed to reproduce wave environments. First, the optimal simulation conditions were derived through numerical tests for the wavemaker and wave absorber, and then the wave loads and wave run-up on a vertical truncated cylinder were estimated and compared with the experimental and other numerical results.

• 대한조선학회논문집
• /
• 제53권4호
• /
• pp.290-299
• /
• 2016

The most powerful energy resource in nature is solar energy which becomes directly converted to electric power in worldwide. Most of the photovoltaic power plants are commonly installed on sunny side of the ground. Thus the installation of photovoltaic power plant could produce an unexpected adverse effect by sacrificing the productivity from green field or forest. To avoid these adverse effect floating photovoltaic plant has been devised and installed on inland reservoir. The photovoltaic plant could utilize ignored water surface without sacrificing the productivity of the ground. Additionally the photovoltaic efficiency has been reenforced by the cooling effect induced by the circulating air flow from water surface. The floating photovoltaic plant could be furnished solar tracking ability by tilting the system operated with the aid of the ballast system. This report is provided to introduce the design of the floating structure with solar panel which furnished solar tracking ability with the aid of ballast system.

• 대한조선학회논문집
• /
• 제51권6호
• /
• pp.530-538
• /
• 2014

The weight estimation of floating offshore structures such as FPSO, TLP, semi-Submersibles, Floating Offshore Wind Turbines etc. in the preliminary design, is one of important measures of both construction cost and basic performance. Through both literature investigation and internet search, the weight data of floating offshore structures such as FPSO and TLP was collected. In this study, the weight estimation model was suggested for FPSO. The weight estimation model using non-linear regression analysis was established by fixing independent variables based on this data and the multiple regression analysis was introduced into the weight estimation model. Its reliability was within 4% of error rate.

• 한국산학기술학회논문지
• /
• 제11권1호
• /
• pp.175-181
• /
• 2010

본 논문에서는 H.264 방식의 full HD실시간영상압축을 위한 율제어 모듈의 새로운 구조를 제안한다. 제안된 구조에서는 각 매크로블록 라인(full HD의 경우 120 매크로 블록, CIF 의 경우 22 매크로 블록)을 따라 율제어 알고리즘을 사용함으로서 QP 가 변경된다. JM의 H.264 율제어 알고리듬에는 복잡한 산술연산과 부동 소숫점 연산을 가지고 있기 때문에, 정수형 산술 CPU 를 통한 율제어 알고리듬의 구현은 불가능하다. 따라서 우리는 부동 소숫점 연산 유닛을 채용하고, 이 부동소숫점 연산 유닛을 이용하여, 율제어 알고리듬을 구현하였으며, 이 하드웨어를 통하여 실시간에 동작할 수 있음을 확인하였다.

• 대한조선학회논문집
• /
• 제52권1호
• /
• pp.43-51
• /
• 2015

This paper presents effect of aerodynamic loads on mooring line responses of a floating offshore wind turbine. A Matlab code based on blade element momentum (BEM) theory is developed to consider aerodynamic loads acting on NREL 5MW wind turbine. The aerodynamic loads are coupled with time-domain hydrodynamic analyses using one-way interaction scheme of the wave and wind loads. A semi-submersible floating platform which is from Offshore Code Comparison Collaborative Continuation(OC4) DeepCWind platform is used with catenary mooring lines simply composed of studless chain links. Average values of mooring peak tensions obtained from aerodynamic load consideration are significantly increased compared to those from simple wind drag force consideration. Consideration of aerodynamic loads also yield larger tension ranges which can be important factor to reduce fatigue life of the mooring lines.

• 대한조선학회논문집
• /
• 제52권1호
• /
• pp.1-7
• /
• 2015

The weight estimation of floating offshore structures such as FPSO, TLP, semi-Submersibles, Floating Offshore Wind Turbines etc. in the preliminary design, is one of direct measures of both construction cost and basic performance. Through both literature investigation and internet search, the weight data of floating offshore structures such as FPSO and TLP was collected. In this study, the weight estimation model with the genetic programming was suggested for FPSO. The weight estimation model using genetic programming was established by fixing the independent variables based on this data. In addition, the correlation analysis was performed to make up for the weak points of genetic programming; it is apt to induce over-fitting when the number of data is relatively smaller than that of independent variables. That is, by reducing the number of variables through the analysis of the correlation between the independent variables, the increasing effect in the number of weight data can be expected. The reliability of the developed weight estimation model was within 2% of error rate.