• 한국철도학회논문집
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• 제10권1호
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• pp.22-28
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• 2007

During the passage of the train, the railway bridge undergoes vibration and noise. The noise of railway bridge can be occurred from various sources. The wheel-rail contact, noise from machinery parts, structural-borne noise, pantagraph noise and aerodynamic noise of the train work in combination. Running train is one of the most important factors for railway bridge vibration. The repeated forces with equidistant axles cause the magnification of dynamic responses which relates with maintenance of the track structure and structure-borne noises. The noise problem is one of the most important issues in services of light rail transit system which usually passes through towns. In the present study, The vibration and noise of the LRT bridge will be investigated with utilizing dynamics responses from moving train as input data for noise analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.1391-1393
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• 2004

This paper described the development of technology for LRT (Light Rail Transit) power system, which are sponsored by MOCT and supervised by KRRI. Especially, manufacture, interface between components and composition for DC Switchgear are focused. Most main components for DC switchgear(Protective Relay, HSCB, DS) are made by own. Also the type test report of international testing laboratory about the DC Switchgear based on IEC regulations is introduced. Finally the product will be proved based on field test.

• Communications for Statistical Applications and Methods
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• 제3권2호
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• pp.175-185
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• 1996

For the Change-point problem in a sequence of binomial variables we consider the maximum likelihood estimator (MLE) of unknown change-point. Its asymptotic distribution is quite limited in the case of binomial variables with different numver of trials at each time point. Hinkley and Hinkley (1970) gives an asymptotic distribution of the MLE for a sequence of Bernoulli random variables. To find the asymptotic distribution a numerical method such as bootstrap can be used. Another concern of our interest in the inference on the change-point and we derive confidence sets based on the liklihood ratio test(LRT). We find approximate confidence sets from the bootstrap distribution and compare the two results through an example.

• 품질경영학회지
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• 제24권2호
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• pp.77-86
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• 1996

In this paper, we consider the problem of testing independence in the absolutely continuous bivariate exponential distribution of Block and Basu(1974). We construct a bootstrap procedure for testing zero and non-zero values of the parameter ${\lambda}_3$ which measures the degree of dependence and compare the power of the bootstrap test with likelihood ratio test(LRT) by Gupta et al.(1984) and the test based on maximum likelihood estimator(MLE) $\hat{{\lambda}}_3$ by Hanagal and Kale(1991) for small and moderate sample sizes.

• 산업경영시스템학회지
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• 제23권56호
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• pp.83-92
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• 2000

This paper presents a study on control schemes for gradual increases (drifts) in a process variance. A new control chart, the Drifting Variance Control Chart (DVCC) is designed using Likelihood Ratio Test (LRT), and the ARL performance of the chart is evaluated for different subgroup sizes. The performance of this chart is then compared to some of the popular control schemes for the process dispersion, like the Shewhart S$^2$chart, the CUSUM chart and the EWMA chart. Results are presented and discussed. Also included is a sensitivity analysis that investigates how the DVCC performs when applied to a stepped change in process variance.

• 통합자연과학논문집
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• 제5권3호
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• pp.151-156
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• 2012

Because of the equivalence between control chart procedures and hypothesis testing, we propose to use likelihood ratio test (LRT) statistic $Z_i^2$ as the multivariate control statistic for simultaneous monitoring means of the multivariate normal process. Properties and comparisons of the proposed control charts are explored and conducted for matched fixed sampling interval (FSI) and variable sampling interval (VSI) with two sampling interval charts. The result of numerical comparisons shows that EWMA chart with two sampling interval procedure is more efficient than the corresponding FSI chart for small or moderate changes. When large shift of the process has occurred, we also found that Shewhart chart is more efficient than EWMA chart.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1501-1514
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• 2008

Recently, so as to solve the urban transportation problem the LRT(Light Rail Transit) system has been studied on the essential technology and the engineering know-how, which lead lower construction cost and higher reliability. The localization development of rubber tired AGT(Automatic Guided Trainsit) system has performed from 1999 to 2004, as a national project of the Minister of Land, Transport and Maritime Affairs. For the application of the rubber tired AGT system in Busan Subway 3-2 Line, this study is focused on the reliability of aluminium profiles vehicle carbody and the establishment of the test and evaluation technologies. In this paper, 3D modeling simulation was applied to the load test of aluminium vehicle carbody. The reliability of the vehicle carbody was estimated as the fatigue test of welded aluminium profiles. From the test and simulation results, it could be concluded that the developed rubber tired AGT shows a good structural reliability and integrity.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1889-1899
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• 2008

Even the terms is strange, "new transport system" was introduced into our country with the beginning of Yong-In LRT in 2005. domestic new transport system market amounts to the 13 trillion Won and 78 projects are intended to or already started construction. In the beginning of introduction, overseas rolling stock companies such as simens, bombardier controlled over the rolling stock market, but after Rotem, WooJin rushed into the market, desperate competing system was equipped between internal and external companies. but each system has advantage and disadvantage, so each project should be analyzed technologically and economically in terms of operators and also users. this research can be helpful to introduce optimal system through the each items' analysis.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1327-1332
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• 2008

Nowadays, the technology development of communication and system engineering should impact on the Train Control System(TCS). The one of main developments in TCS is the Communication Based Train Control(CBTC), which does not depend on the track circuit. Currently, there are the project to modernize TCS as CBTC system from the track circuit system around the world. In Korea, there are the new CBTC system revenue projects such as Busan-Gimhae LRT, Sin-Bundang Line, and so on. There is also Government project called Maglev Line in Daejeon, which is applied CBTC system. Through the examples of world TCS renovation, it is expected to modernize the track circuit TCS system as CBTC system in Korea. Therefore, we would express the advantage of developing from the traditional TCS system to CBTC TCS system.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.325-330
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• 2008

LRT System Application Project is performed for the purpose of technical advancement and stabilization of K-AGT system from the viewpoint of practical use and commercialization. For those purpose, the performance test and evaluation procedure for K-AGT signaling system are developed, and the scheme of verifying the performance and function of signaling system under multi-train and driverless control environment is being conducted. For the multi-train operation in K-AGT test track, we applied the regenerative energy storage system in addition to the existing electric facilities. This paper present the design, manufacturing, and testing results of regenerative energy storage system.