• Journal of the Society of Cosmetic Scientists of Korea
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• v.24 no.3
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• pp.73-80
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• 1998

This Study was performed to get the suitable oil dispersion agent by assessment of color strength of organic pigment in non-aqueous systems. Organic pigment is used as a color expression material with other body pigments in the make-up products. But occasionally aggregation or agglomeration occurs for the lack of affinity with medium, This function is the cause of disturbing homogeneous dispersion, and then bring about an instability of products. Our study, research of dispersion mechanism between the pigment and oil phase, has been executed to solve this problem, and find a oil dispersion agent having optimum dispersion condition. Generally dispersion is related to between the solid-liquid mutual properties and electrical phenomena associated with solid-liquid interface. This factor is determined to input energy, milling time, optical properties, particle size, rheological properties, etc. Ideal dispersion state is told that coloring primary solid particle is homogeneously dispersed in medium. Good dispersed colorants are strongly and clearly appeared. We are already known that the particle size of organic pigment, chemical properties and viscosity of medium, refractive index. Consequently We determine the affinity of medium and organic pigment by measuring of color strength in the same mechanical condition. UV-VISIBLE RECORDING SPECTRO PHOTOMETER is used for measuring apparatus. We can decided the dispersion level of oil dispersion agent by measuring absorbance of color strength in the visible range that diluted medium for colloid colorant particles.

• Proceedings of the Technology Innovation Conference
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• 2003.02a
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• pp.27-40
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• 2003

Though it has been recognized that the accumulation of technological knowledge has been the core competency to reinforce the competitiveness of individual firms and to raise the innovation capability of social and economic systems, only single or fragmentary variables, such as R&D expenditure, R&D stock, the number of researchers and the number of R&D employee have been adopted to measure the amount of technological knowledge. In this research, we use nine conventional technological knowledge measures under the conceptual structure of input-output framework to technological knowledge. Applying correlation and factor analysis, we examine the relationships among the nine proxy measures quantitatively and suggest the new approach for the calculation of technological knowledge index as a aggregated measure.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.166-168
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• 2002

This paper presents a new numerical algorithm suitable for defining recloser reclaims time and blocking automatic reclosing during permanent faults on overhead lines. It is based on terminal voltage input data processing. The decision if it is safe or not to reclose is determined from the voltage signal of faulted and tripped line phase using Total Harmonic Distortion factor calculated by Discrete Fourier Transform. The algorithm was successfully tested using signals recorded on the real power system. The tests demonstrate the ability of presented algorithm to determine the secondary arc extinction time and to block unsuccessful automatic reclosing of HV lines with permanent fault.

• Journal of Technology Innovation
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• v.9 no.2
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• pp.17-33
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• 2001

In the knowledge-based economy, technological knowledge (TK) is reckoned key subject of knowledge management. Despite growing recognition, it has long been considered an intractable task to develop precise measures of TK and, as a remedy, a number of R&D-related proxy indicators have been employed. Although voluminous previous research has examined the structure and process of technological innovation by using proxy indicators, the inquiry into the relationship among respective indicators has remained unexplored. In this research, we take three most frequent proxy indicators of TK, R&D human resources, R&D stock, and patents, and investigate the correlation among respective measures. In addition, the dynamic pattern of time lag between technological input and output is also analyzed.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.5
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• pp.31-36
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• 1983

The indirect M.R.A.C. method using the W.L.S. algorithm is applied to the speed control of a D.C. motor on the assumption that the motor is the 1-st order, completely controllable and observable, non-minimum phase plant. By the help of M6809 microprocessor system the experiments are performed with respect to the sinusoidal and square reference input. The results show that the speed of a D.C. motor is well controlled by the indirect M.R.A.C. method using W.L.S, algorithm, and that the W.L.S. algorithm is quite suitable to the time-varying plant.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.188-191
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• 2002

This paper presents a method for on-line estimation of rotor time constant of induction motor. The proposed method applies a model reference adaptive system(MRAS) using rotor flux vector. The MRAS consists of two independent observers to estimate the rotor flux vector; one based on voltage equations of rotor flux vector, the other based on current equations of them. The MRAS utilizes concept of auxiliary variables to normalize observer output and decrease high-frequency components of its input. Experimental results verify the validity and usefulness of proposed method

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1351-1353
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• 2000

In this paper, it is proposed to constant power control of solar power system. The solar power system has disadvantage that low power density and variable power output. Proposed strategy is controled by DC/DC converter using phase shift PWM and I-PD type control applying type 1 digital system. The validity of proposed control strategy is verified from simulations results using PSIM.

• Journal of Power Electronics
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• v.14 no.4
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• pp.649-660
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• 2014

A novel non-isolated bidirectional soft-switching SEPIC/ZETA converter with reduced ripple currents is proposed and characterized in this study. Two auxiliary switches and an inductor are added to the original bidirectional SEPIC/ZETA components to form a new direct power delivery path between input and output. The proposed converter can be operated in the forward SEPIC and reverse ZETA modes with reduced ripple currents and increased voltage gains attributed to the optimized selection of duty ratios. All switches in the proposed converter can be operated at zero-current-switching turn-on and/or turn-off through soft current commutation. Therefore, the switching and conduction losses of the proposed converter are considerably reduced compared with those of conventional bidirectional SEPIC/ZETA converters. The operation principles and characteristics of the proposed converter are analyzed in detail and verified by the simulation and experimental results.

• Proceedings of the KAIS Fall Conference
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• 2011.12a
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• pp.37-39
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• 2011

광역경제권 선도산업은 지역 간 협력 및 연계를 통해 산업 경쟁력을 높이는 것을 정책 목표로 하고 있어 R&D 경제적 파급효과에 대한 권역별 분석이 요구된다. 본 연구에서는 충청광역경제권 선도산업 중 'New IT' 분야 '차세대무선통신 단말기 부품소재 글로벌 경재력 강화' 프로젝트에 대한 경제적 파급효과를 한국은행에서 발간한 지역산업연관표를 활용하여 분석하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.3
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• pp.573-581
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• 1994

A microstrip antenna having a dual polarization and a smaller size than feed horn polarizer of F.R.R.S(Faraday Rotation Rotary Switch) is designed, in which GaAs MESFET switches are inserted for selective reception of RHCP or LHCP. For an accurate analysis of the resonance frequency, input impedance and radiation pattern of the circularly polarized microstrip antenna, finite difference time domain (FDTD) method is used. When the GaAs MESFET switch in the feeder is ON-stats, the truncated patch antenna has a gain of about 16.6dB including amplifier gain, while the switch is OFF-state, this has a isolation level of -24dB.