• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 추계학술대회 논문집
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• pp.279-285
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• 2007

Since the residential load is an AC load and the output of solar cell is a DC power, the photovoltaic system needs the DC/AC converter to utilize solar cell. In case of driving to interact with utility line, in order to operate at unity power factor, converter must provide the sinusoidal wave current and voltage with same phase of utility line. Since output of solar cell is greatly fluctuated by insolation, it is necessary that the operation of solar cell output in the range of the vicinity of maximum power point. In this paper, DC/AC converter is three phase PWM converter with smoothing reactor. And then, feedforward control used to obtain a superior characteristic for current control and digital PLL circuit used to detect the phase of utility line.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회 논문집
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• pp.679-683
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• 2005

The technique which connects Generalized Regression Neural Networks Model(GRNNM) with Genetic Algorithm (CA) is used to derive rating curve in the river basin. GRNNM architecture consists of 4 layers ; input, hidden, summation and output layer. GA method is applied to estimate the optimal smoothing factor when GRNNM is trained. The derivation of rating curve using GRNNM is considered different kinds of hydraulic characteristics such as water stage, area and mean velocity and is applied two stage stations; Sunsan and Jungam. Furthermore, it is compared with conventional curve-fitting method. Through the training and validation performance, the results show that GRNNM is much superior as compared to the conventional curve-fitting method.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.288-291
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• 2007

Since the residential load is an AC load and the output of solar cell is a DC power, the photovoltaic system needs the DC/AC converter to utilize solar cell. In case of driving to interact with utility line, in order to operate at unity power factor, converter must provide the sinusoidal wave current and voltage with same phase of utility line. Since output of solar cell is greatly fluctuated by insolation, it is necessary that the operation of solar cell output in the range of the vicinity of maximum power point. In this paper, DC/AC converter is three phase PWM converter with smoothing reactor. And then, feedforward control used to obtain a superior characteristic for current control and digital PLL circuit used to detect the phase of utility line.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.181-183
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• 2004

Conventional VVVF control voltage-fed inverter of blower induction motor has advantage that very speedy response characteristics for air-harmonic. But there have bad power factor on input orient have its large volume and high error ratio over 80%. And there are very expensive by reason of using the capacitor input rectifier. In this paper, It could make the smoothing capacitor-less inverter for air-blower motor by using the instantaneous compensation PWM controller. This inverter system has small volume and value compare with the conventional VVVF control inverter for blower induction motor for air-harmonic equipment.

• 한국자동차공학회논문집
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• 제10권2호
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• pp.150-158
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• 2002

Through experimental works, the damping force vibration problem was investigated, which results from valve and surge pressure in the oil return line of the hydraulic circuit of an active suspension system in a passenger cu. Experiments were carried out under passive system, where an orifice valve was closed and non-active system, where an orifice valve was opened, using a pressure control valve controlled by solenoid. The effects of parameters of the valve overlap and accumulator on smoothing surge pressure was elucidated. It was proved that the apparent variation of damping force due to the overlap amount of pressure control valve is the most important factor to control the damping force variation. The procedure of the experimental works shows the development process of a proportional pressure control valve in the hydraulics system of an active suspension system of passenger car.

• 대한전기학회논문지
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• 제37권5호
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• pp.282-288
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• 1988

A Multi-grid method is introduced to Finite Element Analysis of electromagnetic field problems in order to reduce the computational time. The puropse of this work is to study how to intermix discretization and solving process, thereby making the process more effective and to find the optimal factors of Multi-grid method. Several numerical experiments with linear models of uniform and nonuniform grids confirm that the proposed algorithm can reduce the computational time very effectively as compared with con ventional iterative methods. The best results are obtained with V cycle and S.O.R. with the acce leration factor of 1.3-1.4 for smoothing.

• 한국통신학회논문지
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• 제25권6B호
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• pp.1021-1027
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• 2000

In this paper, we propose two new detection-estimation based algorithms that effectively remove impulsive noises in severely corrupted color images. The existing methods for enhancing corrupted color images with impulsive noises commonly possess the inherent problems of excessive computing time and smoothing out edges. However, since our proposed algorithms classify corrupted pixels first in each channel or in each pixel and then perform marginal or vector median filtering only for them, are computationally efficient and preserve edges well. In addition, since there are no appropriate criteria to evaluate the performance of impulsive noise detectors for color images, the objective comparison of noise detectors is difficult. Thus, we introduce a new efficiency factor to compare the performance of noise detectors in digital color images. Simulation results show that the proposed algorithms perform better than the existing methods in terms of both objective and subjective evaluat ons.

• 한국광학회지
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• 제16권4호
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• pp.384-391
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• 2005

본 논문에서는 나노 임프린트 기술을 이용한 폴리머 링 광공진기를 제안하고 구현하였다. 공진기 역할을 하는 링 도파로에서의 전파손실과 링 및 버스 도파로 간의 광파워 결합계수를 빔전파방법을 도입하여 계산하였으며, 또한 전달 매트릭스 방법을 도입하여 이들이 소자에 미치는 영향을 분석하고 소자를 설계하였다. 특히, smoothing buffor layer를 갖는 임프린트용 스탬프를 도입하여 다음과 같은 성과를 얻을 수 있었다. 먼저 식각공정으로 얻어진 스탬프 상의 도파로 패턴의 측면 거칠기를 링 도파로의 산란손실을 개선함으로써 Q값을 획기적으로 향상시켰다. 또한, 결합영역에서 버스와 링 도파로 간의 간격을 기존 lithography 공정에서는 불가능하였던 $0.2{\mu}m$정도까지 효과적으로 줄이고 제어함으로써 링과 도파로 간의 광파워 결합을 정밀하게 조절할 수 있게 되었다. 제작된 소자의 성능을 살펴보면, 링 반경이 $200{\mu}m$인 경우에 대해 1550 nm 파장 대역에서 Q값은 ~103800이고, 소멸비는 ~11 dB, free spectral range는 1.16 nm였다.

• 한국의류산업학회지
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• 제13권4호
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• pp.600-613
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• 2011

The purpose of this study is to provide Torso pattern for Korean middle-aged women using 3D human body scan data. 155 women in their 40's or 50's were measured by Martin's anthropometry. Merging the data of 914 middle aged women provided by Korean agency for technology and standards, total of 1,069 subjects' data were analyzed. For data analysis, ANOVA, factor analysis and cluster analysis were done using SPSS PC+. And representative subject of each cluster was selected and they participated in 3D scanning and Torso pattern suggested for middle-aged women Torso pattern which investing the amount of ease according to each group for diffuse front interscye 30%, armscye circumference 30%, back interscye 40% using 3D human body scan data. The results of this study are as follows. Firstly, as a result of the factor analysis, the first factor was 'obesity index of body', The second factor was 'verticality size of body', The third factor was 'verticality length of upper bodice', The fourth factor was 'drop value to represent silhouette', and the fifth factor was 'physique of upper bodice'. And, middle-aged women type were classified 3 types according to the cluster analysis. Type 1(Y-type) was the long upper Torso with wide shoulder. Type 2(H-type) was flat-body type with comparatively thin upper bodice and thin lower bodice. And type 3(A-type) was the obese type with comparatively thin upper bodice and fat lower bodice. Secondly, using CAD program, point filtering was performed and approximated surface model was made. It used that generated surface smoothing corrected for abnormally extruded points and scattered points based on the curvature information. And 3D surfaces were flatted onto the plane by the internal tools of CAD program. Difference ratios of outline length and area between 3D curves and 2D plane were 0.42% and 0.54%, respectively. Third, wearing test by the sensory evaluation showed that distinct difference almost every category. The movement functionality test shows that, in all the tests which reveal significant differences, especially, 'comparison pattern A' experienced inconvenience to neck width and neck depth.

• 한국신뢰성학회지:신뢰성응용연구
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• 제12권2호
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• pp.67-78
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• 2012

An electric double-layer capacitor(EDLC) is an electrochemical capacitor with relatively high energy density, typically hundreds of times greater than conventional electrolytic capacitors. EDLCs are widely used for energy storage rather than as general-purpose circuit components. They have a variety of commercial applications, notably in energy smoothing and momentary-load devices, and energy-storage and kinetic energy recovery system devices used in vehicles, etc. This paper presents an accelerated degradation test of an EDLC with rated voltage 2.7V, capacitance 100F, and usage temperature $-40^{\circ}C{\sim}65^{\circ}C$. The EDLCs are tested at $50^{\circ}C$, $60^{\circ}C$, and $70^{\circ}C$, respectively for 1,750hours, and their capacitances are measured at predetermined times by constant current discharge method. The failure times are predicted from their capacitance deterioration patterns, where the failure is defined as 30% capacitance decrease from the initial one. It is assumed that the lifetime distribution of EDLC follows Weibull and Arrhenius life-stress relationship holds. The life-stress relationship, acceleration factor, and $B_{10}$ life at design condition are estimated by analyzing the accelerated life test data.