• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.237-240
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• 2004

For the paralleled operation of DC/DC converters, the current sharing between each modules is the most important for the reliability of the power system. Interleaving method is commonly used with many paralleling schemes for the reduction of the ripple in the output voltage of paralleled converters and there are many commercial IC for interleaving application appliable. But for all of them, it is impossible to detect the number of module in operating and then change the phase of them automatically. In this paper, a novel paralleling method is proposed for the converter parallel operation, which detects the number of modules in active and sets the phases of PWM signals applied to each modules autonomously. This can greatly improve the output voltage ripple and reliability of the system. The expandibility of modular number can be done very easily by just adding several parts.

• Journal of the Korean Society of Safety
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• v.29 no.6
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• pp.151-157
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• 2014

This study deals with the rear-end collision at roundabouts. The purpose of this study is to develop the accident models of rear-end collision in Korea. In pursuing the above, this study gives particular attention to developing the appropriate models using Poisson, negative binomial model, ZAM, multiple linear and nonlinear regression models, and statistical analysis tools. The main results are as follows. First, the Vuong statistics and overdispersion parameters indicate that ZIP is the most appropriate model among count data models. Second, RMSE, MPB, MAD and correlation coefficient tests show that the multiple nonlinear model is the most suitable to the rear-end collision data. Finally, such the independent variables as traffic volume, ratio of heavy vehicle, number of circulatory roadway lane, number of crosswalk and stop line are adopted in the optimal model.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.239-242
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• 2009

Power Control and Distribution Unit (PCDU) plays roles of power generation control for solar array panel, power storage control for battery system, power conversion for unregulated and regulated primary bus and power distribution to bus and payload system. The selection and design of the proper auxiliary power interface for PCDU depending on various mission is one of the most important step for electrical power subsystem design. In this paper, the general design approach of auxiliary power interface for PCDU which can be used for small-sized LEO satellites application is given. And, the auxiliary power design concept for always alived modules such as solar array regulator and house keeping module is also suggested.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.339-341
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• 2017

최근 생체인식 서비스가 지속적으로 보급되고 있으나 그에 대한 보안의 문제에 대해서는 개선되고 있지 않는 상황이다. 본 논문에서는 생체인식 보안에 대해서 개선방안을 제안하고자 한다. 무아레 생체 인증의 보안성을 개선하기 위하여 퍼지 추출기를 이용해 무아레 생체 인증의 보안성을 효율적으로 개선하고, 기존에 있던 무아레 생체 인증 보안성과 퍼지 추출기를 이용한 무아레 생체 인증의 보안을 비교하는 방향을 제시한다.

• Journal of Power System Engineering
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• v.17 no.6
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• pp.115-121
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• 2013

This study was carried out to investigate the effect of hot forging on the hardness and impact value of ultra high carbon low alloy steel. With increasing hot forging ratio, thickness of the network and acicular proeutectoid cementite decreased, and than were broken up into particle shapes, when the forging ratio was 80%, the network and acicular shape of the as-cast state disappeared. Interlamellar spacing and the thickness of eutectoid cementite decreased with increasing forging ratio, and were broken up into particle shapes, which then became spheroidized. With increasing hot forging ratio, hardness, tensile strength, elongation and impact value were not changed up 50%, and then hardness rapidly decreased, while impact value rapidly increased. Hardness and impact value was greatly affected by the disappeared of network and acicular shape of proeutectoid cementite, and became particle shape than thickness reduction of proeutectoid and eutectoid cementite.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.2237_2238
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• 2009

This paper describes the design process of three-phase squirrel cage induction moter. stator and rotor were modelled with the result obtained from loading distribution on the provided specification. For proving validity of the result obtained from loading distribution, through Maxwell simulator the first test target values, output and efficency, synchronous speed and etc, were compared with the design result.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1185_1186
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• 2009

철도신호시스템은 열차들의 운행간격과 열차진로를 제어하는 기능을 담당함으로써 열차를 안전하고 효율적으로 운영하는 데 있어 핵심적인 역할을 수행한다. 철도신호시스템의 고장은 열차운행중지를 비롯하여 열차충돌이나 탈선등과 같은 치명적인 사고로 직결될 수 있기 때문에 시스템의 신뢰성과 안전성이 매우 중요하다. 현재까지 철도신호시스템에서는 지존의 지상신호방식이 많이 사용되어 왔으나 지상에 설치된 신호기 현시상태를 기관사가 확인하여 열차속도를 제어함으로써 기관사의 인적 오류 등의 사고 위험이 있다. 아울러 시스템의 수명이 다 되어 시스템절체의 필요성이 있다. 이에 따라 최근에는 컴퓨터 및 통신기술을 이용하여 열차속도제어 정보를 차상으로 송신하고, 차량에서 열차속도를 제어하는 차상신호방식이 도입 적용 되어 효과를 보고 있다. 따라서 수명이 다된 신호시스템을 교체하기 위하여 승객을 위한 운행서비스를 하면서 새로운 방식으로 절체 하는 것이 필요하다. 이에 본 논문에서는 시스템 절체과정의 절차와 시스템검증을 위한 일련의 과정중 간섭의 문제점을 시험평가를 통해 확인하였다.

• The Korean Journal of Food And Nutrition
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• v.10 no.4
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• pp.539-543
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• 1997

This study was carried out to investigate the Chinese and Baek-Seok chive. We collect the volatile components of Chinese and Baek-Seok chive by dynamic head space method. Chinese chive was analyzed by Gas chromatography-Mass Spectrometry(GC-MS). 28 components including 20 sulfides, 5 alcohols, 1 benzene and 2 aldehydes compounds were identified in samples, Also Baek-Seok chive was analyzed by GC-MS. 32 components including 19 sulfides, 10 alcohols, 2 benzonoides and 1 aldehyde compounds were confirmed.

• Proceedings of the KIEE Conference
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• 2008.10a
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• pp.129-130
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• 2008

In this paper, optimal DRIE process conditions for fused quartz are experimentally determined by Taguchi method to develop high-performance inertial sensors based on the fused quartz material, which is known to have high Q-factors. Using Si layer as an etch mask, which was formed by previously developed bonding process of the fused quartz and Si wafer, fused quartz DRIE process was performed. Different 9 flow rate conditions of $C_4F_8$, $O_2$, He gas have been tested and the optimum combination of these factors was estimated. By this work, the ability to fabricate high aspect ratio fused quartz structure was confirmed.

• Journal of the Korean Graphic Arts Communication Society
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• v.22 no.1
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• pp.9-18
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• 2004

Recently as color image processing to be become independent have been desired at the light source in an image processing and it have been enlarged. An image processing of the light source which is become independent means an image processing which uses a spectral reflectance information. We improved it in the spectral reflectance estimation method which uses existing 3-band image in this research that the improvement of an identity color population generation method which uses the hue angle and the processing speed improvement and introduces a labelling method. The precision of a spectral reflectance estimation appeared to the ${\Delta}E^*_{ab}$ of an average 2.7 comparing with the measurement price. The practical use possibility came to be fast and appeared a processing speed compared with existing method.