• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 E
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• pp.1801-1803
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• 1997

The Gas Insulated Switchgear(GIS) has made it an indispensible part of power transmission network. In order that the GIS may have its high reliability, it is necessary to pay careful attention to its whole process e.g., designing, manufacturing, installation, and operation. The main hazard in GIS comes from free conducting particles, which can move and cause breakdown under the influence of the electric field. Although the concentration on protecting the GIS inner part against the free conducting particles is made, it is, actually, almost impossible to avoid the hazard from the particles throughly. In this paper, the corona discharge in GIS initiated by the free conducting particles was discribed through laboratorial experiment The magnitude of the corona discharge voltage was measured using current measuring method by the impedance. The purpose of this experiment is to get fundamental data which is essential to develop GIS diagnosis technology.

• International Journal of Railway
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• 제6권2호
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• pp.78-84
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• 2013

This paper is about the first experiment in Korea that was conducted on speeding increase up with rail speeds at 430km/h at high speed railway of designed 350km/h. and analysis data collected on vibration accelerations of roadbed. There are barely references on roadbed behavior measurement with rail speeds more than 350 km/h in Korea as it has never been conducted the experiment on it. So the experiments were confirmed the reliability through crosschecking the figures/values from respective sensors and measuring devices after measuring EMS and ICP types. Based on the study, values of vibration acceleration were less than 12% compared with the ones that conducted while speeding up of HEMU-430X. Also, figures of HSB for concrete bed tracks were 52% against the standard. According to the results, all the performance evaluation of vibration acceleration for roadbeds in transition zones is under the standard.

• 전기학회논문지
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• 제66권11호
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• pp.1634-1640
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• 2017

The study aims to distinguish hemiplegic gait and normal gait using simple wearable device and classification algorithm. Thus, we developed a wearable system equipped three axis accelerometer and three axis gyroscope. The developed wearable system was verified by clinical experiment. In experiment, twenty one normal subjects and twenty one patients undergoing stroke treatment were participated. Based on the measured inertial signal, a random forest algorithm was used to classify hemiplegic gait. Four-fold cross validation was applied to ensure the reliability of the results. To select optimal attributes, we applied the forward search algorithm with 10 times of repetition, then selected five most frequently attributes were chosen as a final attribute. The results of this study showed that 95.2% of accuracy in hemiplegic gait and normal gait classification and 77.4% of accuracy in hemiplegic-side and normal gait classification.

• 한국음향학회지
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• 제31권4호
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• pp.253-259
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• 2012

Goldingham's measurement of the velocity of sound undertaken in the early nineteenth century was the first large-scale measuring enterprise which considered various meteorological factors such as temperature, humidity, atmospheric pressure, the direction of the wind, etc. Goldingham's successful performance of measuring the velocity of sound by employing the sounds of cannons as sound source in Madras (now Chennai), a colonial region of India, for one and a half years was supported by material, institutional and social resources. As the official astronomer at the Madras Observatory, he was benefitted by the undemanding employment of accurate measuring instruments under the support of the Madras Army enabled him to gain reliable data and his reputation as professional experimentalist facilitated the acknowledgment of their trustworthiness.

• 제어로봇시스템학회논문지
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• 제18권3호
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• pp.208-217
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• 2012

This paper presents two adaptive fingerprint matching methods. First, we experiment an adaptive threshold selection of 1:N matching system in order to raise the reliability of the matching score. Second, we propose a adaptive threshold selection using fitting algorithm for high speed matching. The experiment was conducted on the NITZEN database, which has 5247 samples. Consequently, this paper shows that our suggested method can perform 1.88 times faster matching speed than the bidirectional matching speed. And, we prove that FRR of our suggested method decreases 1.43 % than that of the unidirectional matching.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.192-195
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• 2001

In this report, we firstly have investigated the electrical characteristics of silicon carbide (SiC) schottky barrier diode and compared the characteristics to those of conventional Si diode through simulation and experiment. Secondly we have investigated the influence of two kinds of diodes to the power conversion circuit of the systems. From the investigation results it is verified that SiC schottky barrier diode is more superior to Si diode in thermal and reverse recovery, characteristics, which are the important factors in the size reduction and higher reliability of the systems. Finally though the experiment applied to PFC(Power Factor Correction) circuits, we precisely verified excellency to thermal characteristic of SiC schottky barrier diode any other diode.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2014년도 전력전자학술대회 논문집
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• pp.405-406
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• 2014

This paper presents the one direction 3-phase DC-DC converter. The converter employs DC-AC inverter, 3-phase 1:N transformer and 3-phase full wave rectification circuit make low voltage direct current to high voltage direct current. By computer simulation and experiment, the theoretical results can be verified or modified. Finally, the simulation and experiment results are presented. Compared with the general DC converter, has anti-interference ability, high reliability, high output power, range and other characteristics, widely used, fully isolated input and output, the output of the multiplexer is not limited, polar optional.

• 한국정밀공학회지
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• 제20권3호
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• pp.157-164
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• 2003

The pulse-echo method is one of the most widely used ultrasonic techniques for application of nondestructive evaluation. Particularly, quantitative nondestructive evaluation of defects has been considered more important to assure the reliability and the safety of structure. Frequency energy in adhesive joints is based on the ultrasonic wave analysis. The attenuation coefficient upon wave amplitude and the frequency energy that is expressed in the term of wave pressure amplitude were utilized for the primary wave experiment. By means of a control experiment, it was confirmed that the variation of the frequency energy in adhesive joints depends on transition by stress variation. In this paper, the ultrasonic characteristics were measured for single lap joint and Double Cantilever Beam specimen with different fracture modes that was subjected to stress. Consequently, the data that was obtained from the adhesive specimen was analytically compared to the fracture mechanics parameter

• 한국정밀공학회지
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• 제21권9호
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• pp.127-134
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• 2004

It is difficult to have the existing structural optimization using coupled field analysis from CFD to structure analysis when the structure is influenced of fluid. Therefore in an initial model of this study after doing parameter design from the background of shape using topology optimization. and it is making a approximation formula using by the CFD-structure coupled-field analysis and design of experiment. By using this result, we conducted multi-objective optimization. We could confirm efficiency of stochastic method applicable in the scene of structure reliability design to be needed multi-objective optimization. And we presented a way of design that could overcome the time and space restriction in structural design such as the butterfly valve with the less experiment.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 1992년도 제2회 정기총회 및 추계학술 발표회 발표논문 초록
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• pp.8-8
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• 1992

Through a simulation experiment, often an experimenter is concerned with estimating the system parameters of the linear model consisting of m design points from the outputs oft the simulation model. To improve the estimation of the system parameters and reliability of these estimators, appropriate simulation techniques have been developed. For the first order linear model, Schruben and Margolin (1978) exploited the random number assignment rules which uses a combination of common random numbers and antithetic streams in a simulation experiment designed to estimate the system parameters when the design matrix of simulation model admits orthogonal blocking into two blocks. Nozari, Arnold and Pegden (1984) developed a method for appliying the method of control variates to the situation of the linear model having multiple design points. This talk deals with a different way of utilizing controls under the correlation induction strategy of Schruben and Margolin's to improve the simulation efficiency, and presents a procedure for obtaining the estimators of the system parameters analytically. Simulation results on a selected simulation model indicate a promising evidence that a proposed method may yield better results than Schruben and Margolin's method.