• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.609-614
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• 2001

This paper is to explain reasonable shear behavior that can apply usually to reinforced concrete beams on the basic concepts of existent analysis and experimental research information. This study is succession $paper^{2) 3) 4) 5)}$ of treatise announced in existing and main control variable of reinforced concrete beams with stirrups used internal force state factor($\alpha$). Shear failure of reinforced concrete beams with stirrups is Influenced greatly because of the actual geometrical shape(a/d) of the concrete and flexural reinforcement steel ratio, stirrup reinforcement ratio and concrete compression strength, size effect etc. Therefore, shear behavior of reinforced concrete beams with stirrups that flexural crack is happened can be explained easily through proper extent proposal of internal force state factor($\alpha$) that express internal force state flowing. Use existent variable truss model by analysis model to explain arch action. Also, wish to compose each failure factors and correlation with internal force state factor by function, and when diagonal cracks happens, internal force state factor($\alpha$) study whether shear stress and some effect are.

• 한국공간구조학회논문집
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• 제19권4호
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• pp.69-76
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• 2019

A stadium roof that uses the pin-jointed spatial truss system has to be designed by taking into account the unstable phenomenon due to the geometrical non-linearity of the long span. This phenomenon is mainly studied in the single-free-node model (SFN) or double-free-node model (DFN). Unlike the simple SFN model, the more complex DFN model has a higher order of characteristic equations, making analysis of the system's stability complicated. However, various symmetric conditions can allow limited analysis of these problems. Thus, this research looks at the stability of the DFN model which is assumed to be symmetric in shape, and its load and equilibrium state. Its governing system is expressed by nonlinear differential equations to show the double Duffing effect. To investigate the dynamic behavior and characteristics, we normalize the system of the model in terms of space and time. The equilibrium points of the system unloaded or symmetrically loaded are calculated exactly. Furthermore, the stability of these points via the roots of the characteristic equation of a Jacobian matrix are classified.

• 전자공학회논문지
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• 제50권12호
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• pp.22-29
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• 2013

광대역 주파수 범위에 대해서 무지향성 방사 패턴을 나타내는 실린더형 유전체 공진기와 1/4 파장 길이의 모노폴의 결합구조를 제안한다. 모노폴은 저주파 대역에서 동작하고 DR 은 고주파 대역에서 동작하며 모노폴이 DR 에 전계 결합에 의하여 급전기로서 작동한다. 실린더형 DR에서 광대역 동작을 위해서 아래쪽에 직사각 구조로 식각이 이루어진다. 안테나의 크기는 DR 의 내경, 외경 및 높이가 5.8 mm, 11.6 mm 및 6.0 mm 의 크기이며 10 dB 대역폭은 4.7-18.2 GHz 범위의 대역폭을 나타내었다.

• 한국가구학회지
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• 제25권4호
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• pp.338-344
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• 2014

Modern furniture design is advancing by putting value on individual sensitivity. Accordingly, this study will focus on optical art, which can give various changes in people's sensitivity. Optical art was actively applied in various fields of image, photograph, fashion, textile, accessory and interior from the 1950s till the 1960s. Optical art realized by Victor Vasarely (1908~) opened a new trend in art by accurately realizing concise and precise expressions. This study analyzed the impact of pattern expression on sensitivity in optical art and suggested a method, which can spatiotemporally maximize the emotional change by combining optical art with the form of furniture. Modern furniture design is changing toward the direction of fitting to the propensity and emotional taste of an individual. Accordingly, this study analyzed the emotional expression felt in the furniture modeling works featured by concise, straight and standardized rectangular shape. Based on the result of analysis, this study would like to suggest a method to utilize optical pattern as a means for emotional design, with which people are able to perform various emotional expressions while keeping the function and form of furniture.

• 한국실내디자인학회논문집
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• 제14호
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• pp.10-18
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• 1998

This study aims to make clear visual quality of organic form and structural order that is immanent in nature about a form as formative principles of architectural space design the significanced of this study is to prove the application possibility in to functional form architectural space design. All organic forms in nature has a unique shape and pattern in structure to be self-controled and good in order. Such an order in nature comes from regular construction and ratio principles which has aesthetical order by mathmetics. The specialty of beauty in nature can be revealed not only visual form but also the ratio balance and rhythm of structural principles. As we examine the aesthetic source embodied some object can be developed in to basic principles. Furthermore through this study we can find out that the form construction theory in nature forms share the quality attribute with geometrical form to be shown in architectural space design. Natural forms are ultimate visual expression of power that effects on the architectural space design. The rule of power in nature as nature formal characteristics have a direct influence and can be also applied to architectural construction. Therefore I expect that this study will be linked and continued to another structural view.

• 대한기계학회논문집A
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• 제32권3호
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• pp.217-222
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• 2008

Equal channel angular pressing (ECAP) is one of the effective methods to produce bulk-nano materials by accumulating plastic strain into the workpiece without changing its cross-sectional shape in the multi-pass processing. However, the forming load becomes higher for manufacturing large specimens using conventional solid or split dies because of friction, flash formation, and usage of dummy specimen. In the present investigation, better split die was designed to reduce the forming loads and improve the geometrical accuracy of the specimen in the multi-pass ECAP. The new die exit channel was also designed to reduce the friction effect. Experiments with AA1050 specimens with a square cross-section were carried out to examine the design goal using the proposed split dies for routes A and C up to four passes. The numerical forming simulations were used to determine the effective geometry of various die models in the present work.

• 한국정밀공학회지
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• 제19권8호
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• pp.100-107
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• 2002

The extruder screw is a part for extruding material in a injection molding machine. The screw's geometrical shape can mathematically be described by a sweep surface which is constructed by sweeping a section curve composed of a few circular arcs, along a helical guide curve. In the paper we developed a dedicated CAD system which basically is parametric in a sense that the system initially takes several design parameters to construct the geometric elements including the final sweep surface of the screw as well as section & guiding curves, along with feasibility check of the input parameter values, without further user interaction. The system has been developed as a built-in module onto a commercial CAD system, which can further incorporate additional NC-out functions with ease.

• 대한의용생체공학회:의공학회지
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• 제14권1호
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• pp.23-30
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• 1993

We investigated the structural geometry of thirty-eight Korean femurs. The purpose of this study is to identify major geometrical differences between Korean femurs and others that we believe belong to Caucasians so that we would be able to get insights into the femoral component design that fits Asians including Koreans. We utilized computerized nomography (CT) images of femurs extracted from cadavers. The CT images were transformed into bitmap data by using a film scanner, and then analyzed by using a commercially available software called Image v.1.0 and a Macintosh loci computer. The resulting data were compared with already published data. The major results show that the geometry of the Korean femurs is significantly different from that of Caucasians: (1) the anteversion angle and the canal (tare Index are greater by the amount of approximately 8" and 0.5, respectively, (2) the shape of the isthmus cross section is more round , and (3) the distance between the lesser trochanter and the proximal border of the isthmus is shorter by about 15 mm. The results suggested that the femoral component suitable for Asians should be dif- ferent (rom the currently-used components designed and manufactured mostly by European or American companies.

• 대한의용생체공학회:의공학회지
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• 제7권2호
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• pp.113-116
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• 1986

We investigated the structural geometry of thirty-eight Korean femurs. The purpose of this study is to identify major geometrical differences between Korean femurs 3nd others that we believe belong to Caucasians so that we would be able to get insights into the femoral component design that fits Asians including Koreans. We utilized computerized tomography (CT) images of femurs extracted from cadavers. The CT images were transformed into bitmap data by using a film scanner, and then analyzed by using a commercially available software called Image v.1.0 and a Macintosh IIci computer.The resulting data were compared with already published data. The major results show that the geometry of the Korean femurs is significantly different from that of Caucasians: (1) the anteversion angle and the canal flare index are greater by the amount of approximately 8˚ and 0.5, respectively, (2) the shape of the isthmus cross section is more round, and (3) the distance between the teaser trochanter and the proximal border of the isthmus is shelter by about 15 mm. The results suggested that the femoral component suitable for Asians should be different from the currently-used components designed and manufactured mostly by European or American companies.

• Structural Engineering and Mechanics
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• 제67권4호
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• pp.403-415
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• 2018

In the present study, nonlinear dynamic response of polymer-CNT-fiber multiscale nanocomposite plate resting on elastic foundations in thermal environments using the finite element method is performed. In this regard, the governing equations are derived based on Inverse Hyperbolic Shear Deformation Theory and von $K{\acute{a}}rm{\acute{a}}n$ geometrical nonlinearity. Three type of distribution of temperature through the thickness of the plate namely, uniform linear and nonlinear are considered. The considered element is C1-continuous with 15 DOF at each node. The effective material properties of the multiscale composite are calculated using Halpin-Tsai equations and fiber micromechanics in hierarchy. The carbon nanotubes are assumed to be uniformly distributed and randomly oriented through the epoxy resin matrix. Five types of impulsive loads are considered, namely the step, sudden, triangular, half-sine and exponential pulses. After examining the validity of the present work, the effects of the weight percentage of SWCNTs and MWCNTs, nanotube aspect ratio, volume fraction of fibers, plate aspect, temperature, elastic foundation parameters, distribution of temperature and shape of impulsive load on nonlinear dynamic response of CNT reinforced multi-phase laminated composite plate are studied in details.