• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.30 no.2
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• pp.19-37
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• 2017

Objectives : The study designed to analyze annual, seasonal tendency of outpatients in ophthalmology & otolaryngology & dermatology clinic of Korean Medical hospital from 2012 to 2016. Methods : We investigated annual, seasonal population-social characteristics such as sex or age, departmental characteristics such as ophthalmology, otolaryngology, dermatology, many others, main diagnosis, cost characteristics of treatment period and frequency of treatment those who were received treatment as outpatients in Dunsan Korean Medical Hospital ophthalmology & otolaryngology & dermatology clinic from March 2012 to March 2016. The data was obtained from EMR chart, and statistical analysis was performed using SPSS 19.0. Results : We analyzed population-social characteristics, utilization of new patients in the year, in the season, and we obtained various results. Conclusions : In the analysis of annual, seasonal utilization patterns that outpatients offered in ophthalmology & otolaryngology & dermatology clinic of Korean Medical hospital from 2012 to 2016, the report draws 3 different conclusions.

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1660-1669
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• 2014

Partial discharge (PD) detection plays a major role in the life time assessment of liquid insulation in power transformers. Many research works are being carried out to replace conventional mineral oil insulation in transformers by vegetable oils. It is necessary to understand the PD characteristics of vegetable oils before recommending them as an alternate for mineral oil. In this paper, the breakdown strength and PD characteristics of palm and corn oil were investigated in both unaged and thermally aged conditions. Laboratory experiments were performed as per IEC test procedures. PD signals were measured using wide band detection system. Phase resolved PD pattern of vegetable oils and mineral oil were compared. Effect of increase in voltage stress on the PD pattern of palm and corn oil were studied. Time and frequency domain analysis of PD pulses at needle-plane electrode configuration was carried out. Statistical analysis of PD pattern i.e. skewness and shape parameter variations with respect to applied thermal stress were also carried out. From the results, it is observed that palm and corn oils have better breakdown strength and PD characteristics even under long-term thermal stress and hence they can be used for power transformer applications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.223-224
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• 2005

In this paper, multiple regression analysis of the electrical characteristics for $HfO_2$ thin films grown by metal organic molecular beam epitaxy (MOMBE) was investigated. The electrical properties, such as, the accumulation capacitance and the hysteresis index, are the main factors to determine the characteristics of $HfO_2$ thin films. The input factors on the process are the substrate temperature, Ar gas flow, and $O_2$ gas flow. For statistical analysis, the design of experiments was carried out and the effect plots were used to analyze the manufacturing process. This methodology can predict the electrical characteristics of the thin film growth mechanism related to the process conditions.

• Journal of the Korean institute of surface engineering
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• v.40 no.4
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• pp.165-169
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• 2007

Compared to conventional Indium Tin Oxide (ITO) film deposition methods, cesium (Cs) assisted sputtering offers higher film characteristics in terms of electrical, mechanical and optical properties. However, it showed highly non-linear characteristics between process input factors and equipment responses. Therefore, to maximize film quality, optimization of manufacturing process is essential and process characterization is the first step for process optimization. For this, we designed 2 level design of experiment (DOE) to analyze ITO film characteristics including film thickness, resistivity and transmittance. DC power, pressure, carrier flow, Cs temperature and substrate temperature were selected for process input variables. Through statistical effect analysis methods, relation between three types of ITO film characteristics and five kinds of process inputs are successfully characterized and eventually, it can be used to optimize Cs assisted sputtering processes for various types of film deposition.

• Journal of the Korean Statistical Society
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• v.30 no.3
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• pp.529-539
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• 2001

This paper deals with the distributions of certain characteristics related to a symmetric random walk of an steps ending at an unspecified position, thus generalizing and extending the earlier work.

• Journal of the Korean Data and Information Science Society
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• v.19 no.2
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• pp.487-496
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• 2008

Recently survival analysis becomes popular in a variety of fields so that a number of statistical packages are developed for analyzing the survival model. In this paper, several types of survival models are introduced and considered briefly. In addition, widely used three packages(SAS, SPSS, and STATA) for survival data are reviewed and their characteristics are investigated.

• Communications for Statistical Applications and Methods
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• v.14 no.1
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• pp.121-131
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• 2007

In this paper, we examine the problem of estimating the sensitive characteristics and behaviors in a multinomial randomized response model using Bayesian approach. We derived a posterior distribution for parameter of interest for multinomial randomized response model. Based on the posterior distribution, we also calculated a credible intervals and mean squared error (MSE). We finally compare the maximum likelihood estimator and the Bayes estimator in terms of MSE.

• Communications for Statistical Applications and Methods
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• v.9 no.3
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• pp.577-594
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• 2002

For the estimation and test of long memory feature in volatilities of stock indices and individual companies semiparametric approach, Geweke and Porter-Hudak (1983), is employed. Empirical study supports the strong evidence of volatility persistence in Korean stock market. Most of indices and individual companies have the feature of long term dependence of volatility. Hence the short memory models are unable to explain the volatilities in Korean stock market.

• Journal of the Korean Statistical Society
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• v.32 no.2
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• pp.175-191
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• 2003

An empirical Bayesian approach is discussed for estimation of characteristics from the two-way balanced rotation sampling design which includes U.S. Current Population Survey and Canadian Labor Force Survey as special cases. An empirical Bayesian estimator is derived for monthly effect under presence of two types of biases and correlations It is shown that the marginal distribution of observation provides more general correlation structure than that frequentist has assumed. Consistent estimators are derived for hyper-parameters in Normal priors.

• Communications for Statistical Applications and Methods
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• v.6 no.2
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• pp.413-422
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• 1999

Multivariate EWMA control charts to simultaneously monitor correlation coefficients of correlated quality characteristics under multivariate normal process are proposed. Performances of the proposed charts are measured in terms of average run length(ARL). Numerical results show that smalle values for smoothing constant with accumulate-combine approach are preferred for detecting smalle shifts.