• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.7
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• pp.1-8
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• 2012

In this paper, we improved the light extraction efficiency by structural change of LEDs on conventional LEDs. We simulated the LEDs light emission as functions of LED side wall angle, various refractive indices the geometrical structures and analyzed the condition improved the light efficiency. We present the results of experimerns and simulations for light output power from LEDs for various refractive indices and the geometrical structures of the LED encapsulants. When the side wall angle range was from 40[$^{\circ}$] to 30[$^{\circ}$], the LED emission increased. LED side wall angle onto LED using the simulation system with a fine tuning of the structure of the LEDs side wall angle is fabricated. Additionally, we changed the side wall angle of LED package with spherical structure and flat structure. The result of spherical structure ray tracting is higher compared with flat structure about 14[%].

• Journal of the Korean Society of Costume
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• v.61 no.8
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• pp.85-99
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• 2011

Geometrical figures have been used as artwork motifs from the ancient times to the present day. The area of fashion, being a part of modern art, is also largely influenced by geometry and geometrical shapes are being used as a motif for fashion design now more than ever before. However, studies about geometry in the fashion field are not yet done enough and further research is necessary. This research will therefore investigate the usages of round, square and triangular design in contemporary fashion. The main scope of this research is to look at the type of expression and analyze the intrinsic meanings of these shapes in modern fashion. This research will look profoundly into the general characteristics of these geometrical figures and analyze the effects and uniqueness found in the world collection introduced since 2007. As a result from this study, it was found that round and square objects were perceived in such a straightforward and positive way and these designs, when worn, really completed the final look. On the other hand, the triangular design was used mainly for spatial expansion and was interpreted in a more metaphorical, indirect and abstract way. The intrinsic meaning of round, square and triangle figures in contemporary fashion consists of the informal features that really steps out of the formative clothing structure. The topological changes that is formed from the interactive functions and the wholism that creates a new system through integration of the human body and clothing contains the intrinsic meaning of these geometrical figures. Based on the research results, the method of expression and the characteristics of modern day fashion's geometrical figures was able to be easily understood. This work provides the useful information on the development of fashion design and the extended interpretation of clothing structure.

• Communications of Mathematical Education
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• v.23 no.2
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• pp.175-196
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• 2009

In this paper we analyze Ziv's geometrical differentiated teaching and learning materials using inner structure of mathematics problems. In order to analyze inner structure of mathematics problems we in detail describe problem solving process, and extract main frame from problem solving process. We represent inner structure of mathematics problems as tree including induced relations. As a result, we characterize low-level problems and middle-level problems, and find some differences between low-level problems and middle-level problems.

• Journal of the Korean Geographical Society
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• v.41 no.2 s.113
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• pp.227-243
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• 2006

This paper reviews how electronic media technologies involve and produce time-space dimensions in geometrical spaces, focusing on four theoretical perspectives: van Dijk's dual structure of networks as scale extension and reduction; Latour's actor-networks as fluid and hybrid networks; Virilio's dromospherical time as global media vectors; and Castells' timeless time as non-sequential flows. In these four theoretical perspectives, we can see that electronic media technologies involve different and multiple time-space dimensions in geometrical media spaces: from the two-dimensional spaces (surfaces) of concentric circles, through the one-dimensional spaces (lines) of actor-networks to the zero-dimensional spaces (points) of dromospherical time and finally to the multi-dimensional spaces (hypertexts) of timeless time. The paper concludes by suggesting that we need to explain electronic media spaces not only in terms of geometrical media spaces but also in terms of geographical media spaces in order to understand the ways in which electronic media spaces are dis/embedded in geographical spaces.

• Journal of Korean Association for Spatial Structures
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• v.3 no.4 s.10
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• pp.77-84
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• 2003

Tensegrity systems are stable structures which are reticulated spatial structures composed of compressive straight members, struts and cables. But there are some difficulties concerning surface stability, surface formation and construction method. One of the ways to solve this problem reasonably is combination of tesile members and rigid members. This structure is a type of flexible strutural system which is unstable initially because the cable material has little initial rigidity. Therefore tensegrity structure need to be introduced to the Initial stress for the self-equilibrated system having stable state. The rigidification of tensegrity systems is related to selfstress states which can be achieved only when geometrical and mechanical requirements are simultaneously satisfied. In this paper, for the stabilization of tesnsegrity structure it is proposed the modified self-equilibrated equation and the range of the various geometrical parameter about unit system. And we generate the model of double layed single curvature arch using the new squew quadruplex unit system.

• Journal of the Korean earth science society
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• v.26 no.2
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• pp.160-165
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• 2005

A series of high resolution spectra of CH Cygni obtained at the Bohyunsan Optical Astronomy Observatory (BOAO) in April 2004 has been analyzed. The emission components of the [O I] 6300 A lines are de-convoluted and fitted with Gaussian functions in order to investigate the characteristics and the structure of CH Cygni system along with the analysis for $H{\alpha}$ and [O III] lines. A present geometrical structure of the components of CH Cygni system is suggested.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.161-161
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• 2011

The design methodology of the sluice caisson structure is one of important factor that is closely related to the efficiency in tidal power generation. When the sluice caisson is designed to maximize the water discharge capability, it is possible to minimize the number of sluice caissons for attaining the water amount required for achieving the target power generation, which results in reduction of the construction cost for the sluice caisson structure. The discharge capability of sluice caisson is dependent on the geometrical conditions of an apron structure which is placed in both sides of the sluice caisson. In this study, we investigated numerically the variation of water discharge capability of sluice caisson according to the geometrical conditions of apron. Flow fields are simulated with FLOW-3D software using VOF method.

• Journal of the Microelectronics and Packaging Society
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• v.9 no.3
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• pp.13-17
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• 2002

In ceramic systems, many components including embedded passives and TRL(transmission line) are used for composition of 3-dimensional circuit. So the exact analysis on this components must be performed. As for the TRL's, material properties including electrical conductivity of metal, loss factor and effective dielectric constant of dielectric material and geometrical factors like roughness of surface, vias, dimension of stripline structure have a large effect on the charactersistics of transmission lines. In this research, effect of material and geometrical factors on the characteristics of stripline structure is analyzed and quantified by simulation and measurement.

• Korean Institute of Interior Design Journal
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• no.26
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• pp.95-103
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• 2001

This study was performed to search for the geometrical principles in modern architecture and design based on Frobel's educational idea and Kindergarten system. Especially, it studies on the geometrical principles of Froebel's building gifts and it's types, and then illustrates applied examples in modern architecture and design. As the architectural scope, the architecture and design theory of Frank Lloyd Wright and Bauhaus in early 20th century is analyzed. The conclusions of this study that starts these purpose are as follows. First, Froebel's educational theory is based on principles and rules which are perceived through the observation of nature, and Froebel's Kindergarten system consists of geometrical building gifts and categories of geometrical forms. Second, the characteristics of Froebel's building gifts are mathematical size, proportion, symmetry and the rules of spatial relation. Third, the influence of Froebel's kindergarten system on Bauhaus is that it based on the rational rules of $\bigtriangleup\square\bigcirc$ organized by geometrical basic forms as like Froebel's educational idea. And the influence of Froebel's Kindergarten system on Frank Lloyd Wright is that he used unit system, unity of space and structure and modular system as like the Froebel's building gifts.

• Structural Engineering and Mechanics
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• v.71 no.5
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• pp.485-502
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• 2019

In this research, the nonlinear static, buckling and vibration analysis of viscoelastic micro-composite beam reinforced by various distributions of boron nitrid nanotube (BNNT) with initial geometrical imperfection by modified strain gradient theory (MSGT) using finite element method (FEM) are presented. The various distributions of BNNT are considered as UD, FG-V and FG-X and also, the extended rule of mixture is used to estimate the properties of micro-composite beam. The components of stress are dependent to mechanical, electrical and thermal terms and calculated using piezoelasticity theory. Then, the kinematic equations of micro-composite beam using the displacement fields are obtained. The governing equations of motion are derived using energy method and Hamilton's principle based on MSGT. Then, using FEM, these equations are solved. Finally the effects of different parameters such as initial geometrical imperfection, various distributions of nanotube, damping coefficient, piezoelectric constant, slenderness ratio, Winkler spring constant, Pasternak shear constant, various boundary conditions and three material length scale parameters on the behavior of nonlinear static, buckling and vibration of micro-composite beam are investigated. The results indicate that with an increase in the geometrical imperfection parameter, the stiffness of micro-composite beam increases and thus the non-dimensional nonlinear frequency of the micro structure reduces gradually.