• 한국해양공학회지
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• 제17권1호
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• pp.8-15
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• 2003

본 논문에서는 투과성 유연막이 수면밑 일정한 깊이에 수평으로 잠겨있을 때 투과성 유연막에 의한 파랑제어성능을 살펴보았다. 해석 방법으로는 유체문제는 고유함수전개법 (Eigenfunction expansion method)을 사용하였고, 유연막과 파랑의 상호작용문제는 Newmann 이 제시한 유탄성 이론 (hydro-elastic theory)을 채택하였다. 막의 투과성 효과를 고려하기 위하여 수평막에서의 수직속도는 수평막 상하의 압력차에 선형적으로 비례하며 그들 사이에는 위상차가 없다고 가정한 Darcy 법칙을 사용하였다. 투과성 수평막의 설계변수 (초기장력, 길이, 잠긴 깊이, 공극율)와 입사파의 주파수를 바꿔가면서 반사율과 투과율 그리고 에너지 손실율을 살펴보았다.

• International Journal of Aeronautical and Space Sciences
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• 제18권2호
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• pp.245-254
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• 2017

In this paper, deployment dynamics of large-scale flexible solar arrays with deployable mast is investigated. The adopted solar array system is introduced firstly, then kinematic description and kinematic constraint equations are deduced, and finally, dynamics equation of the system is established by the Jourdain velocity variation principle and a new method to deal with topology changes of the deployable mast is introduced. The dynamic behavior of the system is studied in detail. Simulation results indicate that the proposed model is effective to describe the deployment dynamics of the solar arrays and that the introduced method is applicable for topology changes.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.551-556
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• 2004

The Korean Train eXpress(KTX) which started in last April has got many complaints of passengers. This is caused by weak connections between KTX and traditional trains. This paper shows the methods to increase the connection in 3 points of view; business, operation and rolling stocks. For the flexible business, it is necessary that the connecting trains must be multi-purposefully for the satisfaction of KTX transferring passengers and existing commuting passengers. And the expanding of free class is needed. A free class is the base of business flexibility. In an operation point of view, I show the method that can decrease pains for getting transfer. Finally, for the effective using of rolling stocks, I propose that TC(trailer with control) car is added to existing locomotive and passenger coach set. In concluding, KTX needs strong connections with traditional trains. This will bring more competitive power with other transportation systems. And that method must get flexible and various service, in addition to effective and minimizing investment.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.768-773
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• 1999

This study of concrete movement confronting a scope inspects the problems about the waterproofing method and leakage/repairment at present and research the mechanism with the variety of applying examples introducing adhesion and inflation using the flexible type of waterproofing and repairement and the subsititution method developed with polymer resign composite. The polymer resign transmited into adhesion or inflation materials under wet environment absorbs adjoining moisture, wraps impurities of concrete surface, get the waterproofing layer and concrete surface adhere toughly, reorganize the impaired waterproofing layer and get over the detachment of it from concrete surface.

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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• 제6권1호
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• pp.7-14
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• 2003

The interaction of monochromatic incident waves with a submerged horizontal porous membrane is investigated in the context of two-dimensional linear hydro-elastic theory. It is assumed that the membrane is made of material with very fine pores so that the normal velocity of the fluid passing through the porous membrane is linearly proportional to the pressure difference between two sides of the membrane (e.g. Darcy's law). Using the Eigen-function expansion method, the wave-blocking performance of a submerged horizontal porous membrane is tested with various membrane tensions, porosities, lengths, and submerged depths. It is found that an optimal combination of design parameters exists for given water depth and wave characteristics.

• 한국정밀공학회지
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• 제8권4호
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• pp.107-117
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• 1991

The dynamic stability problem of nonconservative system is one of the important problems. In this study, flexible missile with mass variation is regarded as a free Timoshenko beam subjected to a controlled follower force. The stability was studied numerically through the finite element method. Through the study, the obtained results are as follows: [1] Without force direction control (1) In the case of no mass reduction, the existence of concentrated mass increases critical follower force. (2) Mass reduction rate of the beam slightly effects on the change of critical follower force. [2] With force direction control (1) Shear deformation parameter S contributes insignificantly to the force at instability when $S{\geq}10^4$. (2) With mass variation, increase of concentrated mass increases critical follower force at instbility. (3) The type of promary instability is determined by the sensor location.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1999년도 제14차 학술회의논문집
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• pp.21-24
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• 1999

There-have been many control strategies for the enact joint position tracking of flexible manipulators, but direct cartesian space tracking control methods an not developed well. In this paper, we propose a PD control method based on the cartesian error in the end point trajectory tracking. the proposed controller is composed of PD control combined with nonlinear saturation term hut has a very simple form. the effect of this term is continuous suppression of vibration which is induced by the coupling of rigid motion. This control works both on the regulation and on the tracking cases. The performance and validity of this control method is shown by simulation examples.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.890-895
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• 1990

A theoretical and experimental study of a single link flexible arm a tip mass is presented for the translational end-point positioning. The problem of shifting the end-point from its initial position to the commanded position by the amount of W $_{d}$ is considered for the open loop control such that the base follows up the given path function. The theoretical results are obtained by applying the method of the Laplace transform to the governing equation, and the solution is calculated by the method of numerical inversion. Experimental results are obtained and compared with the theoretical ones.s.

• 전자공학회논문지SC
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• 제41권4호
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• pp.1-12
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• 2004

본 논문에서는 적응 퍼지 백스테핑 알고리즘을 이용하여 단일축 유연관절 로봇을 제어하는 새로운 알고리즘을 제안한다. 퍼지시스템은 일반근사기로 사용하여 로봇과 제어기의 비선형성과 불확실성을 상쇄하는 역할을 한다. 제안한 알고리즘은 추가적인 교시 제어기를 필요로 하지 않으며 추적오차를 상시유계시키는 특성이 있다. 끝으로 컴퓨터 모의실험을 통하여 제안한 방식의 성능을 확인한다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 봄 학술발표회 논문집
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• pp.61-68
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• 2003

Cable domes deform very largely because of the characteristics of flexible hybrid system and pre-tension, and include geometrical non-linearity in those structural behavior. Especially wind load is more dominant than seismic loads, because cable domes are flexible structures whose stiffness is very small and self-weight is very light. Therefore, in this paper, Modified Stiffly Stable Method is applied to analyze the nonlinear dynamic behavior of cable domes and compared these results with ones of Newmark-β Method which is generally used. The Seoul Olympic Gymnastic Arena is taken as an numerical example and three kinds of models with giving each different intensity of pre-tension are selected. And dynamic nonlinear behavior of cable domes are analyzed by artificial spectrum of wind velocity wave which is similar to actual wind loads.