• Journal of the Korean Institute of Telematics and Electronics
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• v.19 no.6
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• pp.41-51
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• 1982

This paper proposes a method of analyzing the effect of non-ideal VIS (Voltage Inverter Switch) operation on SCF characteristics. In the special case of the VIS realized with only one switch, equivalent circuits of the elements proposed in [1]. [2]. [3] are obtained from the above results. Applying these results, SCF's operating at higher frequency than the conventional ones can be implemented and the equivalent circuits of most SC circuits can be obtained. Expermental results of a low-pass filter and a band-stop filter show good agreements with the theoretical characteristics.

• Journal of the Korean Society of Safety
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• v.18 no.1
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• pp.101-107
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• 2003

Dynamic behavior of flexible rectangular liquid storage structures is analysed by the developed method. The rectangular liquid storage structures are assumed to be fixed to the ground and a moving coordinate system is used. The irrotational motion of invicid and incompressible ideal fluid is represented by two analytic solutions. One is the solution of the fluid motion in the rigid rectangular liquid storage structure due to ground motions and the other is the solution of the fluid motion by the motion of the wall in the flexible rectangular liquid storage structure. The motion of structure is modeled by finite elements. The fluid-structure interaction effect is reflected into the coupled equation of motion as added fluid mass matrix. The free surface sloshing motion and hydrodynamic pressure acting on the wall in the flexible rectangular liquid storage structure due to the horizontal ground motion are obtained by the developed method and verified.

• Nuclear Engineering and Technology
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• v.32 no.5
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• pp.433-445
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• 2000

The interfacial area concentration (IAC) is one of the most important parameters in the two-fluid model for two-phase flow analysis. The IAC can be measured by a local conductivity probe method that uses the difference of conductivity between water and air/steam. The number of sensors in the conductivity probe may be differently chosen by considering the flow regime of two-phase flow. The four sensor conductivity probe method predicts the IAC without any assumptions of the bubble shape. The local IAC can be obtained by measuring the three dimensional velocity vector elements at the measuring point, and the directional cosines of the sensors. The five sensor conductivity probe method proposed in this study is based on the four sensor probe method. With the five sensor probe, the local IAC for a given referred measuring area of the probe can be predicted more exactly than the four sensor probe. In this paper, the mathematical approach of the five sensor probe method for measuring the IAC is described, and a numerical simulation is carried out for ideal cap bubbles of which the sizes and locations are determined by a random number generator.

• Journal of Satellite, Information and Communications
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• v.8 no.4
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• pp.37-42
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• 2013

In this paper, we propose a compensation method of a non-ideal antenna array and a computationally efficient estimation method of the direction of arrival (DOA) for the antenna array. For DOA estimation, an antenna array is essential. By using the phase difference between the output signals of antennas, we can derive the DOA. In practice, however, mutual coupling between the elements of an antenna array change the beam pattern of each element and degrade the performance of DOA estimation. In the proposed method, we first estimate the DOA for the mid-subarray of the array, where all elements undergo relatively same coupling effect. We use the estimation of signal parameters via rotational invariance techniques (ESPRIT) algorithm to estimate the DOA. Then, we expand the array based on the estimated DOA by compensating the coupling effect. Simulation results show that the proposed method is effective when jamming to noise power ratio (JNR)is relative low.

• Journal for History of Mathematics
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• v.27 no.1
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• pp.67-79
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• 2014

When imaginary numbers were first encountered in the 16th century, mathematicians were able to calculate the imaginary numbers the same as they are today. However, it required 200 years to mathematically acknowledge the existence of imaginary numbers. The new mathematical situation that arose with a development in mathematics required a harmony of real numbers and imaginary numbers. As a result, the concept of complex number became clear. A history behind the development of complex numbers involved a process of determining a comprehensive perspective that ties real numbers and imaginary numbers in a single category, complex numbers. This came after a resolution of conflict between real numbers and imaginary numbers. This study identified the new perspective and way of mathematical thinking emerging from resolving the conflicts. Also educational implications of the analysis were discussed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1993.10a
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• pp.25-32
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• 1993

The design theory of a generalized n-way power divider with arbitrary dividing rations for CATV and/or MATV systems which consists of ideal multi-winding transformers and resistors only was presented. Since the circuit elements have not frequency dependence the proposed power divider is to be of exetremely broad band-width. Furthermore as a result of computer simulation the frequency characteristics are very good in spite of errors of turn numbers and hence it was confirmed that the proposed design theory is valid.

• The Research Journal of the Costume Culture
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• v.13 no.5 s.58
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• pp.763-776
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• 2005

The purpose of this study is to analyze the glamour image in contemporary women's fashion since 1990. The method of study is to analyze the documentary and fashion magazines about the glamour images. Most of all, glamour has been composed by connection of hollywood film industry and fashion. Glamourous body image showed sensual, threatening and vague body. Formative characteristics in fashion showed a tight silhouette, neglige, lace look, dress showing neck and shoulder, fur coat, stiletto, diamond, gold, big and thick jewelry, satin, velvet, lace, mink and fox fur, etc. Internal meaning was a fantasy, ideal, wealth, fame, hyper-feminity, vagueness, vulgarity, sexuality, mystery, professional, fatalness, aggressiveness and evil. Since 1990, the glamour images in fashion were as follows; First, the glamour with hyper-feminity showed a classical femme-fatal image as fearful existence with a power more than allure. Second, the glamour with vulgarity showed an exaggerated, cheap and popular kitsch image, which have intense colors, lavish surfaces and excessive sexual signs. Third, the glamour with classical sensuality showed a hi-glamour image of hollywood actresses being active from 1930 to 1950, which was expressed glittery dress, stole, diamond, fur wrap, hill, luxury dress. Fourth, the glamour with sexual perversion showed an erotic, vague and sexual drag image, and fetish costume. Fetishistic elements were rubber, PVC, stiletto, thick and high boots and corset and particularly, they were a main method of expression of glamour image. Fifth, the glamour with future image showed a mechanical and mysterious image and it was a conscious style by metallic, plastic and sleeky fabric. In conclusion, glamour fashion image is an ideal beauty type of women and will exist as a meaningful aesthetic sign in women's fashion.

• Journal of The Korean Digital Architecture Interior Association
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• v.9 no.3
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• pp.77-83
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• 2009

Van Doesburg founded the magazine De Stijl with Mondrian in 1917. De Stijl movement was influenced by Cubist painting as well as by the mysticism and the ideas about ideal geometric forms in the neoplatonic philosophy. De Stijl proposed ultimate simplicity and abstraction by using only straight horizontal and vertical lines and rectangular forms. Furthermore, their formal vocabulary was limited to the primary colours, red, yellow, and blue, and the three primary values, black, white, and grey. The works avoided symmetry and attained aesthetic balance by the use of opposition. Vertical and horizontal lines are positioned in layers or planes that do not intersect, thereby allowing each element to exist independently and unobstructed by other elements In 1924 their different concepts about space and time were split between Van Doesburg and Mondrian. Van Doesburg launched a new concept for his art, Elementarism, which was characterized by the diagonal lines and rivaled with Mondrian's Neo-Plasticism. The works of De Stijl would influence the Bauhaus style and the international style of architecture.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.7
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• pp.661-668
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• 2011

Direction estimation of signal of interest has been an important issue in radar and communication system. Generally, DOA(Direction Of Arrival) methods have been researched in the field of signal processing with ideal array sensors. However, there are some problems in array antennas such as the input signal distortions in amplitude and phase, due to the mutual coupling between array elements. In this paper, we propose a new method of DOA estimation in the dipole array antenna by using the method of moment(MoM) to compensate the mutual coupling effects between array antenna elements. Also, the proposed method is applied to the estimation of azimuth(${\phi}$ ) and elevation(${\theta}$) angles using uniformly linear dipole array under noisy environments.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.5
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• pp.1033-1042
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• 1994

Dynamic behavior of flexible rectangular liquid containers is analyzed by a two-dimensional coupled boundary element-finite element method. The irrotational motion of inviscid and incompressible ideal fluid is modeled by boundary elements and the motion of structure by finite elements. A singularity free integral formulation is employed for the implementation of boundary element method. Coupling is performed by using compatibility and equilibrium conditions along the interface between the fluid and structure. The fluid-structure interaction effects are reflected into the coupled equation of motion as added fluid mass matrix and sloshing stiffness matrix. By solving the eigen-problem for the coupled equation of motion, natural frequencies and mode shapes of coupled system are obtained. The free surface sloshing motion and hydrodynamic pressure developed in a flexible rectangular container due to horizontal and vertical ground motions are computed in time domain.