• 전기학회논문지P
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• 제58권2호
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• pp.214-220
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• 2009

Battery is one of the emergency power and its reliability is a very important to keep up the minimum of building capabilities in case of interruption of electric power. This paper, a comparison was made between three different types of instrument on 30 valve regulated lead acid(VRLA) TYPE 12[V]/100[AH] batteries, and then their indicated measured values(impedance/conductance) were compared with the measured capacity of the battery. As a result, Measured value of instrument is strongly related to battery's capacity in the same group battery and Impedance/Conductance guide line for diagnosis of lead-acid battery's state of health(SOH) is a different from each battery guoup.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2001년도 학술대회논문집
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• pp.51-58
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• 2001

This paper gives a type and high-frequency waves analysis of in-rush current cab be flowed into distribution automatic machine to be installed in distribution line in order to use minimizing operation error of failure indicator to have been issue recent with obtaining high-frequency component that can be different from current. The in-rush and fault current data studied in this paper is to be surveyed actually in USA distribution system substation line of Bryan Power Company near Texas A. M University, to be occurred high impedance fault.

• 대한산업공학회지
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• 제24권2호
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• pp.251-260
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• 1998

This paper deals with a simulated annealing neural network model for determining sequences of models inputted into a mixed model assembly line. We first present a energy function fitting to our problem, next determine the value of the parameters of the energy function using convergence ratio and the number of searched feasible solution. Finally we compare our model NMS with the modified Thomopoulos model. The result of the comparison shows that NMS and Thomopoulos offer a similar output in the problems having good smoothness.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.173-178
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• 1998

An automatic Q. C. tester for a production line of electric grinder is developed using vibration signals. The methods of measuring and analyzing the vibration signals are found through several experiments at laboratory and production line. The experiments show that checking a vibration signal at running condition only, without any sound signal, is enough to judge whether the product is good or not. The Q. C. tester is made of accelerometer and PC. Measured vibration signal using accelerometer is transmitted to PC through A/D board. Vibration level are calculated using FFT algorithm in PC for already selected five frequency bands, which can specify the cause of fault. The Judging criteria of vibration levels of each bands are decided through a lot of experiment with the comparison of manual judgement.

• 대한교통학회지
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• 제6권2호
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• pp.49-56
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• 1988

Alternate use of lane at a signalized intersection is a quite different control of the operation of an intersection. This control introduces a new stop line and signal before the original stop line. All of the lanes between the two stop lines are used for left turn traffic or through traffic at a time. The purpose of the control is increasing the capacity of a n intersection without widening the approach width. this paper contains a study on the condition of a application, the proper distances between the two stop lines, the reasonable offsets(rear) to guarantee clearing the vehicles of previous phase, the comparison of approach capacity between the existing control and this control. The study results reveals that the offsets(rear) are rather stable showing the range(maximum value minus minimum value) of it's value does not exceed 3.6 seconds according to the field data. The approach capacity will be increased by 27%, 43%, 59%, 84% when the distances between the stop lines are 30.0m respectively. The control might have theoretical limitation to operate in practice. So an experimental application of the control at some suitable intersections prior to expanding it.

• 대한기계학회논문집A
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• 제28권1호
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• pp.70-78
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• 2004

This paper presents study of efficiency of wavelet transformation for on-line chatter detection during hard fuming process. From comparison with other time series and statistical methods such as fast fourier transformation (FFT), Kurtosis and standard deviation (STD), wavelet transform is better than others in on-line chatter detection. With using wavelet function with pseudo frequency corresponding to chatter frequency, chatter could be detected more sensitively. And for both force signal from dynamometer and displacement signal from capacitance type cylindrical sensor (CCS), wavelet transform with DB2 function on level 4 could be well used for chatter detection in hard turning process.

• 전기학회논문지
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• 제66권5호
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• pp.870-876
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• 2017

In this paper, we proposed the automatic vision inspection system using multi-layer perceptron to detect the defects occurred on rail surface. The proposed system consists of image acquisition part and analysis part. Rail surface image is acquired as equal interval using line scan camera and lighting. Mean filter and dynamic threshold is used to reduce noise and segment defect area. Various features to characterize the defects are extracted. And they are used to train and distinguish defects by MLP-classifier. The system is installed on HEMU-430X and applied to analyze the rail surface images acquired from Honam-line at high speed up to 300 km/h. Recognition rate is calculated through comparison with manual inspection results.

• 한국응용과학기술학회지
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• 제21권3호
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• pp.238-245
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• 2004

The interaction between anion and zwitterionic surfactants was investigated by means of surface tension, NMR spectroscopy, and fluorescence studies. These systems are N-tetradecyloxymethyl-N,N-dimethyl betaine ($C_{14}$, TDB), N-octadecyloxymethyl-N,Ndimethyl betaine ($C_{18}$, ODB), and sodium dodecylethoxy sulfate (SDE). These systems show a composition dependency in micellar properties. When the molar fraction of TDB and ODB was about 0.6, the cmc values of these systems showed minima, whereas the solubilized amount of a water insoluble dye, NMR line width showed maxima. These changes comes from the intramolecular complexes formed in the mixed micelles. The complexes are due to the electrostatic interaction of oppositely charged head groups of betaine and sodium dodecylethoxy sulfate. A comparison of betaine and SDE alkyl methylene group line widths to those of n-methyl group indicates that the interior of the micelle in the restricted region is more immobile than the head group.

• Journal of Power Electronics
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• 제9권3호
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• pp.354-364
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• 2009

Rotor resistance variation due to changing rotor temperature is a significant issue in the design of induction motor controls. In this work, a new on-line rotor resistance estimator is proposed based on an alternate qd induction machine model which provides better mathematical representation of an induction machine than the classical qd model (which uses constant parameters). This is because the former simultaneously includes leakage saturation, magnetizing path saturation, and distributed circuit effects in the rotor conductors. The comparisons via computer simulation studies show the ability of the proposed estimator to accurately track rotor resistance variation. For the experimental studies, due to the difficulty in measuring the actual rotor resistance, comparison of the controller performance using the proposed estimator, the classical qd model based estimator, and no estimator is made.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.595-601
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• 2004

The pantograph for Korean High Speed Train was developed and had been evaluating by through 'G7-R&D project' for home grown high speed train technology. In this paper, from the point of view in mechanical aspect, comparison study on the current collection characteristics between the KHST pantograph and contact wire in catenary system on the High-Speed Line and Ho-Nam/Kyoung-Bu conventional lines is conducted. A measuring system for the performance and mechanical characteristics of the KHST pantograph is used for this study, which was developed and installed on the Proto-type Korean High Speed Train, and physical characteristics were measured while the KHST runs on the High-Speed Line and conventional lines. Through this study, remarkable variations of characteristics which can affect to a current collection quality of high-speed train are found and analyzed from measured mean contact forces in both tracks.