• International Journal of Naval Architecture and Ocean Engineering
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• 제10권1호
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• pp.95-102
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• 2018

This paper proposes a dual lifting and its cooperative control system with two different kinds of floating cranes. The Mega-erection and Giga-erection in the ship building are used to handle heavier and wider blocks and modules as ships and off-shore platforms are enlarged. However, there is no equipment to handle such Tera-blocks. In order to overcome the limit on performance of existing floating cranes, the dual lifting is proposed in this research. In the dual lifting, two floating cranes are well-coordinated to add up the lift capabilities of both cranes without any loss such that virtually a single crane is lifting, maneuvering and unloading. Two main constraints for the dual lifting are as follows: First, two barges of floating cranes should be constrained as a rigid body not to cause a relative motion between two barges and main hooks of the two cranes should be controlled as main hooks of a single crane. In order words, it is necessary to develop the cooperative control of two floating cranes in order to sustain a center of gravity of the module and minimize the tilting angle during the lifting and unloading by the two floating cranes. Two floating cranes are handled as a master-slave system. The master crane is able to gather information about all working conditions and make a decision to control the individual hook speed, which communicates the slave crane by TCP/IP. The developed control system has been embedded in the real floating crane systems and the dual lifting has been demonstrated five times at SHI shipyard in 2015. The moving angles of the lifting module are analyzed and verified to be suitable for hoisting control. It is verified that the dual lifting can be applied for many heavier and wider blocks and modules to shorten the construction time of ships and off-shore platforms.

• Journal of Advanced Research in Ocean Engineering
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• 제4권1호
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• pp.25-34
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• 2018

In this study, the behavior of the coupled mooring system and floating body is analyzed. The related works are introduced for the mooring analysis of the floating body. Equations motion are introduced for calculating mooring force connected with the floating body. For formulating the equations of motion, the concept of the constrained force is applied for compact expression of it. The input and output data of the module for calculating mooring force is defined. The static analysis and quasi-static analysis are performed. For the analysis, equilibrium equation for elastic catenary mooring line is used by employing finite element method, and the C# solver is developed in this research. The analysis results are validated by comparing with other research results.

• International Journal of Naval Architecture and Ocean Engineering
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• 제8권1호
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• pp.53-65
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• 2016

The interaction between incident waves and a floating rectangular breakwater with the vertical porous side plates has been investigated in the context of the two-dimensional linear potential theory. The matched eigenfunction expansion method(MEEM) for multiple domains is applied to obtain the analytic solutions. The dependence of the transmitted coefficients and motion responses on the design parameters, such as porosity and protruding depth of side plates, is systematically analyzed. It is found that the non-dimensional wavelength where the sudden drop of transmission coefficients occurs, corresponds to the heave resonant frequency obtained from Ruol et al. (2013) for $\pi$-type floating breakwater. It is concluded that both properly selected porosity and deeper protruding depth of side plates are helpful in reducing the transmission coefficients and also extending the wider applicable extent of incident wavelength for performance enhancement.

• International Journal of Naval Architecture and Ocean Engineering
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• 제8권3호
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• pp.277-300
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• 2016

The motion of a floating body and the free surface flow are the most important design considerations for ships and offshore platforms. In the present research, a numerical method is developed to simulate the motion of a floating body and the free surface using a fixed rectilinear grid system. The governing equations are the continuity equation and Naviere-Stokes equations. The boundary of a moving body is defined by the interaction points of the body surface and the centerline of a grid. To simulate the free surface the Modified Marker-Density method is implemented. Ships advancing in regular waves, the interaction of waves by a fixed circular cylinder array and the response amplitude operators of an offshore platform are simulated and the results are compared with published research data to check the applicability. The numerical method developed in this research gives results good enough for application to the initial design stage.

• 대한기계학회논문집A
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• 제36권12호
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• pp.1489-1495
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• 2012

본 논문에서는 부유식 플랫폼의 동적 거동을 고려하여 해상 풍력 발전기 타워의 구조 해석을 수행하였다. 풍력 발전기는 플랫폼, 타워, 낫셀, 허브 그리고 3 개의 블레이드로 구성된다. 타워는 3 차원 빔 요소를 사용하여 탄성체로 모델링하여 탄성 다물체계 동역학을 기반으로 한 운동 방정식을 구성하였다. 회전하는 블레이드에는 블레이드 요소 운동량 이론에 따라 계산된 공기역학적 힘이 적용되었고, 부유식 플랫폼에는 유체정역학적 힘, 유체동역학적 힘 그리고 계류력이 적용되었다. 타워의 구조 동역학적 거동을 수치적으로 시뮬레이션하였다. 시뮬레이션 결과를 이용하여 굽힘 모멘트와 응력을 산출하고 허용치와 비교하였다.

• 한국실내디자인학회논문집
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• 제22권4호
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• pp.23-32
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• 2013

This study represents something in common and differences of organic characteristics between early modern architecture and contemporary architecture analysing F. L. Wright's Robie House and Toyo Ito's Sendai Mediatheque. A natural organic body cannot be separated from the natural environment, and each part of an architecture has each own property and forms a whole at the same time. That is a basic concept of organic architecture, and a framework for analysis is set up based on it. The followings are similarities and differences of organic concept and interpretation between Wright's Robie House and Ito's Sendai Mediatheque First, Wright' Robie house unites with the natural surrounding, using a physically close connection to the ground. In contract, Ito's Mediatheque shows characteristics of noncentural and fluidic space that are metaphorically reflecting tangible and intangible of factors in modern city, where there is an ambiguous physical boundary between architecture and urban environment. Next, floors, walls and ceilings of Wright's housing as for basic building blocks are physically separated and at the same time form formative unity from the point of view of a physical and structural organic body. And continuous flow of faces of separated walls form an organism united with the nature from a physical aspect. On the contrary to this, there is an no-boudary and floating organic architecture of integrated structure from ambiguous setting of relation between architecture and urban space in Ito's architecture. Especially, Mediatheque shows semantic integration of floating urban environmental factors through horizontal and vertical integration of horizontal slabs, vertical pipes, and skins. Last, horizontal and vertical factors of Wright' Housing is appreciated as an basic experienced structure in terms of spacial perception and fluidic inner spaces in Wright's housing is completed with a series of spatial experiences in a visual sense. On the other hand, no-boundary and floating space of Ito's architecture accept user's physical and virtual body. Especially, there is an integration transcending beyond time and space, accepting an imaginary body and events with the course of time at Ito's Mediatheque.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.1153-1156
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• 1998

We describe a design of a simple but efficient floatingpoint processing architecture expoiting concurrent execution of scalar instructions for high performance in general-purpose microprocessors. This architecture employs 3 stage pipeline asyncronously working with integer processing unit to regulate instruction flows between two arithmetic units.

• 한국해양공학회지
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• 제26권6호
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• pp.53-58
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• 2012

An experimental study on the hydrodynamic performance of a backward bent duct buoy (BBDB) was performed in a 2D wave tank. The BBDB is one of the promising oscillating water column (OWC) types of floating wave energy converters. Two different corner-shaped BBDBs (sharp-corner and round-corner) were used to measure the maximum chamber surface elevations and body motions for various incident wave conditions, and their hydrodynamic characteristics were compared. In order to investigate the effect of the pneumatic pressure inside the chamber, the heave and pitch angle interacted with elevations were compared for both open chamber and partially open chamber BBDBs. From the comparison study, the deviation in the chamber surface elevations between the two shapes of BBDBs was found to be significant near the resonance period, which may be explained by viscous energy loss. It was also found that the pneumatic pressure noticeably affected the chamber surface elevation and body motions.

• 한국항해항만학회지
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• 제36권3호
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• pp.215-223
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• 2012

플로팅 함체의 강성변화가 상부 철골모멘트연성골조에 미치는 영향을 확인하기 위해 함체의 높이를 1.5m, 2.0m, 2.5m로 변화시키면서 파랑하중 3초에서 15초에 대하여 동적 유체 해석과 그에 따른 파력을 산정하고 정적 구조 해석을 수행하였다. 해석결과, RAO-피치와 상부 골조의 모멘트 증가량이 선형적인 관계이고 함체의 곡률이 구조물의 강성과 반비례함을 확인하였다. 이러한 선형적 결과를 종합하여, 임의의 함체에 대한 상부골조의 해석 결과를 이용하여 함체 높이가 다른 경우에도 상부 골조의 모멘트를 추정하는 절차를 제안하였으며, 추정결과가 해석결과와 상당히 잘 일치함을 확인하였다.

• 한국항해항만학회지
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• 제36권3호
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• pp.253-259
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• 2012

마리나클럽을 중심으로 한 마리나는 앞으로 예상되는 해양관광 및 해양레포츠 수요에 대비한 필수적인 시설이다. 국내 여건을 반영하여 마리나와 마리나클럽은 요트수용 대수를 기준으로 한 규모와 프로그램에 따라 레포츠소형, 복합소형, 레포츠중형, 복합중형, 레포츠대형, 복합대형의 6가지 유형으로 구분할 수 있다. 서울마리나, 아라마리나, 전곡마리나 등 3개의 국내 마리나클럽을 분석한 결과 마리나전용 시설과 상업시설의 공간 비율은 평균 21% : 79% 로 나타났다. 단기적으로는 현재의 공간 구성을 유지하는 방향으로 복합형 마리나클럽 계획이 우선 시 될 것으로 예상되며, 장기적으로는 마리나전용시설 비율이 높은 레포츠형 마리나클럽으로 전환될 것으로 보인다. 또한 플로팅 마리나클럽은 해양관광 및 해양레포츠 체험을 극대화하는 친수공간 확보에 매우 유리하다.