• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2771-2773
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• 2001

날씨변화와 차량의 속도차이 등으로 주어지는 외란은 차량번호판을 인식하기 위한 전처리 작업인 영상 추출에 어려움을 준다. 따라서 이러한 외란으로 부터 강인하면서도 효과적으로 번호판을 추출하기 위한 방법으로 Background Marking 방법을 제안한다. 이 방법은 차량의 종류에 따른 번호판 색상 및 인식을 어렵게 하는 여러가지 조건들을 고려함으로써 차량번호판을 보다 효과적으로 추출하는 방법이다. 또한, 히스토그램 정규화를 사용하여 밝기의 차이에 의한 영상의 손상을 보상함으로써 보다 선명한 차량번호판 영상을 습득 할 수 있게 된다. 제안된 방법을 주행 중 또는 주차 중인 차량영상에 적용하여 성능을 검증하였다.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2735-2737
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• 2001

비젼 검사시스템에서 기판에 존재하는 납 형상의 패턴을 분류함으로써 사전에 불량을 줄일 수 있다. 이러한 경우 대부분의 불량은 부정확한 납의 위치 및 두께로 인해 발생하게 되는데, 이러한 문제를 해결하기 위해 주어진 경계 내에 불분명하게 형성된 납의 형태 및 두께를 정상과 불량으로 분류하기 위해 무게중심점에 기초한 정합과 XOR연산을 이용한 비젼 검사시스템을 제안하였다. 제안한 비젼 검사시스템을 인쇄회로기판상의 납땜형상 패턴에 적용하여 제안한 방법의 성능을 검증하였다.

• Journal of the Korean Ceramic Society
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• v.53 no.5
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• pp.541-547
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• 2016

In developing high temperature molds with advantages of the sand and precision (investment) castings, mechanical properties of the mold were improved through homogeneous coating of starting powders with an inorganic binder and improvement of fabrication process. Beads with mullite composition were employed for properties of the mold under high temperature, which was compared with artificial sands. Precursors of silica and sodium oxide were used as starting materials for an inorganic binder to achieve homogeneous coating on the starting powders. Strength was enhanced by the glass phase converted from the inorganic binder through heat treatment process. Also, two kinds of process, wet and dry processes, were incorporated to prepare mold specimens. Consequently, fabrication process of the mold with superior strength and high temperature applicability, compared with the previous molds for sand casting, could be suggested through control of the starting material and enhancement of the vitrification efficiency.

• Journal of the Korean Data and Information Science Society
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• v.23 no.3
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• pp.605-616
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• 2012

This article deals with the problem of testing on the common mean of several normal populations. We propose Bayesian hypothesis testing procedures for the common normal mean under the noninformative prior. The noninformative prior is usually improper and yields a calibration problem that makes the Bayes factor to be defined u to a multiplicative constant. So we propose the default Bayesian hypothesis testing procedures based on the fractional Bayes factor and the intrinsic Bayes factors under the reference priors. Simulation study and an example are provided.

• Journal of the Korean Data and Information Science Society
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• v.22 no.6
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• pp.1265-1273
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• 2011

This article deals with the problem of testing the equality of the location parameters in the half-normal distributions. We propose Bayesian hypothesis testing procedures for the equality of the location parameters under the noninformative prior. The non-informative prior is usually improper which yields a calibration problem that makes the Bayes factor to be defined up to arbitrary constants. This problem can be deal with the use of the fractional Bayes factor or intrinsic Bayes factor. So we propose the default Bayesian hypothesis testing procedures based on the fractional Bayes factor and the intrinsic Bayes factors under the reference priors. Simulation study and an example are provided.

• Journal of the Korean Data and Information Science Society
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• v.23 no.4
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• pp.833-841
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• 2012

In this paper, we develop the noninformative priors for the ratio of the scale parameters in the half logistic distributions. We develop the first and second order matching priors. It turns out that the second order matching prior matches the alternative coverage probabilities, and is a highest posterior density matching prior. Also we reveal that the one-at-a-time reference prior and Jeffreys' prior are the second order matching prior. We show that the proposed reference prior matches the target coverage probabilities in a frequentist sense through simulation study, and an example based on real data is given.

• Journal of the Korean Data and Information Science Society
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• v.18 no.3
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• pp.833-845
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• 2007

When X and Y have independent exponential distributions, we develop a Bayesian testing procedure for the ratio of two quantiles under reference prior. The noninformative prior such as reference prior is usually improper which yields a calibration problem that makes the Bayes factor to be defined up to a multiplicative constant. So we develop a Bayesian testing procedure based on fractional Bayes factor and intrinsic Bayes factor. We show that the posterior density under the reference prior is proper and propose the Bayesian testing procedure for the ratio of two quantiles using fractional Bayes factor and intrinsic Bayes factor. Simulation study and a real data example are provided.

• Journal of the Korean Data and Information Science Society
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• v.20 no.3
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• pp.601-614
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• 2009

This paper derives noninformative priors for scale parameter of exponential distribution when the data are collected in multiple step stress accelerated life tests. We nd the objective priors for this model and show that the reference prior satisfies first order matching criterion. Also, we show that there exists no second order matching prior. Some simulation results are given and using artificial data, we perform Bayesian analysis for proposed priors.

• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.807-813
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• 2012

In this paper, we introduce data mining techniques for short-term load forecasting (STLF). First, we use the K-mean algorithm to classify historical load data by season into four patterns. Second, we use the k-NN algorithm to divide the classified data into four patterns for Mondays, other weekdays, Saturdays, and Sundays. The classified data are used to develop a time series forecasting model. We then forecast the hourly load on weekdays and weekends, excluding special holidays. The historical load data are used as inputs for load forecasting. We compare our results with the KEPCO hourly record for 2008 and conclude that our approach is effective.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.11a
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• pp.367-370
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• 2005

Electric train is currently used widely, and much development is expected. But, in case of electric train, as comparison with diesel rolling stock, many electrical problem such as harmonic, voltage sag, EMI, EMC usually occur. Accordingly, in order to popularize an electric train, first, a study on electrical problem at an electric train must be accomplished. In this paper, one of electrical problems, arc characteristics according to loss of contact between pantograph and catenary was analyzed.