• 한국항공우주학회지
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• 제31권3호
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• pp.1-7
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• 2003

본 연구에서는 저 레이놀즈 수 유동장에서 유연 익형의 공탄성적 거동과 공기 역학적 성능이 평가되었다. 유연 익형은 비정상 유동장에서 저 레이놀즈 수 익형으로 흔히 사용되는 CLARK-Y 익형 윗면의 일정부분에 질량이 없는 박막을 장착하여 모델링 하였다. 박막의 거동은 공기역학적 힘과 박막의 평형 방정식에 의해 지배되며 평형 방정식의 무차원화로부터 유동과 박막간의 상호작용을 나타내는 무차원 변수가 도출되며 이 무처원 변수가 박막의 거동에 큰 영향을 미친다. 박막의 분포를 익형 윗면의 지정된 지점에서부터 뒷전까지 분포시키되 지정된 박막 분포의 시작점을 변화시켜가며 각 박막 분포에서 박막의 공탄성적 거동을 지배하는 무차원 변수에 대해 공기역학적 성능의 최적화를 수행하였다. 그 결과 박막 분포의 시작점이 뒷전으로 이동할수록 무차원 변수는 거의 선형적으로 증가해야함을 알 수 있었다.

• Structural Engineering and Mechanics
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• 제29권5호
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• pp.489-504
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• 2008

In piezoelectric flexible structures, the contribution of vibration modes to the dynamic response of system may change with the location of piezoelectric actuator patches, which means that the ability of actuators to control vibration modes should be taken into account in the development of modal reduction model. The spatial $H_2$ norm of modes, which serves as a measure of the intensity of modes to system dynamical response, is used to pick up the modes included in the reduction model. Based on the reduction model, the paper develops the state-space representation for uncertain flexible tructures with piezoelectric material as non-collocated actuators/sensors in the modal space, taking into account uncertainties due to modal parameters variation and unmodeled residual modes. In order to suppress the vibration of the structure, a dynamic output feedback control law is designed by imultaneously considering the conflicting performance specifications, such as robust stability, transient response requirement, disturbance rejection, actuator saturation constraints. Based on linear matrix inequality, the vibration control design is converted into a linear convex optimization problem. The simulation results show how the influence of vibration modes on the dynamical response of structure varies with the location of piezoelectric actuators, why the uncertainties should be considered in the reductiom model to avoid exciting high-frequency modes in the non-collcated vibration control, and the possiblity that the conflicting performance specifications are dealt with simultaneously.

• 한국터널지하공간학회 논문집
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• 제10권4호
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• pp.371-382
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• 2008

본 연구의 목적은 국내터널현장에서 강지보재로 주로 사용되어지고 격자지보재(Lattice Gilder)의 공학적인 성능을 보다 객관적으로 판단하기 위한 실내성능평가기법의 제안에 있다. 본 연구를 위하여 국내에서 격자지보재로 주로 사용되는 $LG-50{\times}20{\times}30$, $LG-70{\times}20{\times}30$, 및 $LG-95{\times}22{\times}32$를 사용하여 3-point 휨강도 실험 및 4-point 휨강도 실험을 수행하였다. 또한, 하중재하위치에 따른 격자지보재의 하중-변위거동을 분석하기 위하여 각각의 실험방법에서 두 가지 하중재하방식을 사용하여 실험을 수행하였다. 각 부재에 스트레인 게이지를 부착하여 각각의 실험방법에 따라 각 부재에 작용하는 하중분포를 분석하였다. 3-point 휨강도 실험에 적용한 두 가지 하중재하방식으로 측정된 평균 최대하중은 $10%{\sim}33%$까지 차이가 나타났으며, 4-point 휨강도 실험에 적용한 두 가지 하중재하방식에 의해 측정된 평균 최대하중은 거의 차이가 없었다. 4-point 휨강도 실험의 평균 최대하중은 3-point 휨강도 실험보다 $13.56%{\sim}31.55%$와 정도 크게 나타났다. 3-point 휨강도 실험은 주강봉에 주로 하중이 집중되는 반면 4-point 휨강도 실험은 각 부재로 비교적 골고루 하중이 작용하는 것으로 나타났다.

• 한국실내디자인학회논문집
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• 제17권1호
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• pp.60-68
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• 2008

The aim of this study is to elucidate the meaning of "less is more" by examining the design process of the Farnsworth House and its spatial composition. In order to find out what constitutes "less" and "more", Mies' sketches and drawings were reviewed, and the vision of the architect and the owner, and the responses from the critics were studied. As a matter of fact, these seemingly contradictory concepts the "less" and the "more" are relative terms that complement each other. The concept of "less" describes an enclosure of space, fixed, inflexible and invariable space that leaves no room for change. On the other hand, the term "more" represents an openness of space, free, flexible, and variable space. Mies tried to minimize "less" element when designing the interior of the Farnsworth House, and he did so by eliminating columns and walls. On the contrary, by using only fixed core, he created a "more" space, where the effects of flexible and open qualities are maximized. However, duality and contradiction rising from glass external wall and portico in the Farnsworth House raise a critical issue in this "less is more" discourse. The role of these parts of the house is rather contradictory, and the glass wall and the portico hold both "less" and "more" elements. Unlike its relatively simple composition of space, the Farnsworth House encompasses many complex and contradictory ideas that leave room for wide scope of exploration and various interpretations.

• 한국의류산업학회지
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• 제15권5호
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• pp.671-681
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• 2013

Persona means the mask of personality where the internal ego exposes itself to the outside. The complicated structure and diversity of contemporary society has provided men with a more variegated and diversified persona; in addition, advancements in internet and information communications creates the possibility for the emergence of more variegated and new persona. This study probes the persona of virtual space expressed in fashion designs; subsequently, this study reviews the concept and various characteristics of persona and examines the type of persona in the virtual space from the perspective of the manifestation of identity. The type of persona in the virtual space canbe categorized into flexible identity and falsified identity; subsequently, the characteristics and meanings of virtual space persona in fashion designs are analyzed. Flexible identity-oriented personas expressed in fashion designs are revealed through the images of animals or dolls. This is a childlike persona expression that expresses ego through other substances in an effort to express infantile substances such as dreams and fantasy cherished in childhood. Falsified identity-oriented personas are expanded as a realm of expression of the body and the realities are camouflaged as transformed persona. Negating existence itself by covering the eyes or face as well as the concealment of the body with masks or veils is an expression of a self-denying persona.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국제학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.987-992
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• 1988

In recent years there has been much interest in using light-weight, higher performance arms for both commercial and space-based applications, leading to the research of flexible robot manipulator. This paper is concerned with the trajectory control of a flexible arm using inverse dynamics. Inverse problems are important to robot control and programming, since they allow one to find the appropriate inputs necessary for producing the desired outputs. The input is obtained by the numerical inversion of Laplace transformation in the time domain. And we attempt the trajectory control experiment of a flexible arm using this calculated input. In this article we compare the numerical results with experimental results and can find good agreement. The results make clear that this technique has the good potential for the control of tip trajectory of flexible robot arms.

• 한국항해학회지
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• 제21권1호
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• pp.109-118
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• 1997

In this paper, applications of multilayer neural networks to control of flexible robot beam are considered. The multilayer nerual networks can be used to approximate any continuous function to a desired degree of accuracy and the weights are updated by Gradient Method. When a flexible beam is rotated by a motor through the fixed end, transverse vibration may occur. The motor torque should be controlled insuch a way that the motor rotates by a specified angle, while simultaneously stabilizing vibration of the flexible manipulators so that is arrested as soon as possbile at the end of rotation. Accurate control of lightweight beam during the large changes in configuration common to robotic tasks requires dynamic models that describe both rigid body motions, as well as the flexural vibrations. Therefore, a linear dynamic state-space model of for a single link flexible robot beam is derived and PD controller, LQP controller, and inverse dynamical neural networks controller are composed. The effectiveness the proposed control system is confirmed by computer simulation.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.422-427
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• 2001

The component mode synthesis method allows the elastic deformation of each component in the flexible multibody system by a sum of modes and modal coordinates. This paper focuses on the selection of boundary conditions and deformation modes for redundantly constrained flexible components in mechanical system dynamics. The result of a flexible body dynamic analysis with only normal modes is used to identify proper boundary conditions of a static modes and a desired set of static modes which will be used in the final model. A simple four bar mechanism is used to explain the procedure and a space satellite with solar panels is analyzed using the proposed method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1281-1285
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• 2004

There are numerous emotions in the human world. Human expresses and recognizes their emotion using various channels. The example is an eye, nose and mouse. Particularly, in the emotion recognition from facial expression they can perform the very flexible and robust emotion recognition because of utilization of various channels. Hybrid-feature extraction algorithm is based on this human process. It uses the geometrical feature extraction and the color distributed histogram. And then, through the independently parallel learning of the neural-network, input emotion is classified. Also, for the natural classification of the emotion, advancing two-dimensional emotion space is introduced and used in this paper. Advancing twodimensional emotion space performs a flexible and smooth classification of emotion.

• 한국실내디자인학회논문집
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• 제14호
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• pp.27-32
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• 1998

Present structure design has a problem arising from the fact that present apartment housing design doesn't satisfy user's diverse demand. An aim of this study on searching out the alternative to solve this problem. The results of study are as follows : 1) Methods of flexible structure are analyzed to reflect user's needs and practical example of those proposed. 2) To raise the flexibility of design reinforced concrete pannel wall system are selected. The basic types of T and II for the figures of pannel are adopted. As a result it brought so much open space not having influenced on the load of construction that it enhances the flexibility of the space allocation. Also that made it easy to meet the user's demand for 8 kinds of plan types are easily designed according to the arrangement of the space and its scale. These results will become basic data of future unit plan design in apartment housing.