• Communications for Statistical Applications and Methods
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• 제18권2호
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• pp.189-199
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• 2011

In this paper, we develop the noninformative priors for the common intraclass correlation coefficient when independent samples drawn from multivariate normal populations. We derive the first and second order matching priors. We reveal that the second order matching prior dose not match alternative coverage probabilities up to the second order and is not a HPD matching prior. It turns out that among all of the reference priors, one-at-a-time reference prior satisfies a second order matching criterion. Our simulation study indicates that one-at-a-time reference prior performs better than the other reference priors in terms of matching the target coverage probabilities in a frequentist sense.

• Journal of the Korean Statistical Society
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• 제20권2호
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• pp.191-201
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• 1991

Given a set of data pxN$_{i}$, matrices X$_{i}$ observed from p-variate normal populations $\prod$$_{i}$~N($\mu$$_{I}$, $\Sigma$$_{i}$) for i=1, …, K, the test for equality form of the covariance matrices is to choose a hypothetical model which best explains the homogeneity/heterogeneity structure across the covariance matrices among the hypothesized class of models. This paper describes a test procedure for selecting the best model. The procedure is based on a synthesis of Bayesian and a cross-validation or sample reuse methodology that makes use of a one-at-a-time schema of observational omissions. Advantages of the test are argued on two grounds, and illustrative examples and simulation results are given.are given.

• Journal of the Korean Statistical Society
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• 제19권1호
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• pp.24-44
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• 1990

The purpose of this paper is to extend the idea of Tamhane and Bechhofer (1977, 1979) concerning the normal means problem to some general class of distributions. The key idea in Tamhane and Bechhofer is the derivation of the computable lower bounds on the probability of a correct selection. To derive such lower bounds, they used the specific covariance structure of a multivariate normal distribution. It is shown that such lower bounds can be obtained for a class of stochastically increasing distributions under certain conditions, which is sufficiently general so as to include the normal means problem as a special application. As an application of the general theory to the scale parameters problem, a two-stage elimination type procedure for selecting the population associated with the smallest variance from among several normal populations is proposed. The design constants are tabulated and the relative efficiencies are computed.

• Journal of the Korean Statistical Society
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• 제16권2호
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• pp.92-101
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• 1987

Our interest is to access in some way teh relative odds or probability that a multivariate observation Z belongs to one of k multivariate normal populations with unequal covariance matrices. We derived the empirical Bayes posterior odds ratio for the classification rule when population parameters are unknown. It is a generalization of the posterior odds ratio suggested by Gelsser (1964). The classification rule does not have complicated distribution theory which a large variety of techniques from the sampling viewpoint have. The proposed posterior odds ratio is compared to the Gelsser's posterior odds ratio through a Monte Carlo study. The results show that the empiricla Bayes posterior odds ratio, in general, performs better than the Gelsser's. Especially, for large dimension of Z and small training sample, the performance is prominent.

• Journal of the Korean Data and Information Science Society
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• 제24권1호
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• pp.189-200
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• 2013

In this paper, it will be assumed that there are two distinct populations which are multivariate normal with equal covariance matrix. We also assume that the two populations are equally likely and the costs of misclassification are equal. The classification rule depends on the situation whether the training samples include missing values or not. We consider the conditional bootstrap confidence intervals for classification error rate when a block of observation is missing.

• 한국산림과학회지
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• 제103권2호
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• pp.196-202
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• 2014

본 연구는 팥배나무의 열매에 대한 우수개체 선발을 위한 기초자료를 얻고자 11개 집단에서 총 107개체를 선발하여 선발목 열매의 형태적 특성 변이를 조사하고 주성분 분석과 군집분석을 실시하였으며 열매 특성에 의한 선발효과를 추정하였다. 주성분 분석 결과, 제4 주성분까지 75.4%의 설명력을 나타냈으며 군집분석에서는 4 그룹으로 구분되어짐을 알 수 있었다. 열매 수확량과 관련된 특성인 열매 폭과 길이 그리고 송이 당 수확량 특성을 대상으로 광교산1, 2와 덕유산7 그리고 마니산 29, 30 등 5개체의 우수개체 후보목을 선발하였다. 선발개체 5본에 대해서 전체 평균 형질과 비교하여 선발효과를 추정한 결과, 열매 폭은 122.8%, 열매 길이는 115.5%, 송이 당 수확량은 182.7%의 선발효과를 추정할 수 있었다.

• Journal of Preventive Medicine and Public Health
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• 제32권4호
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• pp.513-525
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• 1999

Objectives : High-normal blood pressure' is a factor influencing decision to initiate targeted intensive intervention strategy in westernized populations. JNC-VI offered the vigorous lifestyle modification for persons with 'high-normal blood pressure', who could be early detected. As a hypertension seems to be the result of multiple genetic factors operating in concert with associated environmental factors, it will be necessary to identify the high-normal blood pressure as a risk factor of hypertension for applying primary prevention strategy in Korean people. Methods : Although cohort study design might be adequate to recruit incidence cases, to keep time sequence of events, and to prevent information bias, nested case-control study was chosen for avoiding measurement errors because hypertension is a benign disease. Source population was the 'Seoul Cohort' participants and follow-up was done by using Korea Medical Insurance Corporation's database on the utilization of health services from 1 Jan93 to 30Jun97. Incidence cases were ascertained through the chart review, telephone contacts, and direct blood pressure measurements. Controls included the pairing of 4 individuals to each case on the basis of age. Results : As 75% of 247 incident cases had high-normal blood pressure, the crude odds ratio for hypertension was 2.04 (95% CI 1.47-2.83). Another statistically significant risk factors of hypertension were body mass index, dietary fiber, alcohol consumption, weekly activity and history of quitting smoking. The multivariate odds ratio of high-normal blood pressure adjusted for all risk factors was 1.84 (95% CI 1.31-2.56). Among high-normal blood pressure group, body mass index, weekly ethanol amounts, weekly physical activity, and dietary fiber except history of quitting smoking were still risk factors of hypertension. Conclusion : 'High-normal blood pressure' is a risk factor for hypertension in Korean middle-aged men, which represents that the vigorous lifestyle modification for persons with 'high-normal blood pressure' is need.

• 한국통계학회:학술대회논문집
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• 한국통계학회 2003년도 춘계 학술발표회 논문집
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• pp.85-90
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• 2003

In this paper we develop a method for finding optimal ordering of K statistical models. This is based on a dependent paired comparison experimental arrangement whose results can naturally be represented by a completely oriented graph (also so called tournament graph). Introducing preference probabilities, strong transitivity conditions, and an optimal criterion to the graph, we show that a Hamiltonian path obtained from row sum ranking is the optimal ordering. Necessary theories involved in the method and computation are provided. As an application of the method, generalized variances of K multivariate normal populations are compared by a Bayesian approach.

• Journal of Yeungnam Medical Science
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• 제22권2호
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• pp.199-210
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• 2005

전 세계적으로 비만 인구의 급격한 증가와 이로 인한 다양한 만성질환의 증가가 중요한 건강 문제로 대두되고 있으며, 최근 여러 종류의 암들도 비만과 연관성이 있을 것이라는 연구들이 많이 이루어지고 있다. 비만과 암과의 연관성에 대한 정확한 기전은 아직 밝혀지지 않았으나 다양한 스테로이드와 펩타이드 호르몬 그리고 성장인자가 중요한 역할을 할 것으로 생각되어지며, 전립선암 역시 호르몬 의존성의 종양이므로 남성 비만 환자에서의 증가된 혈청 에스트로겐 농도와 교감 신경계의 활성화 등 비만과 관련된 호르몬의 변화는 전립선암과도 상당한 연관이 있을 것으로 추정된다. 그러나, 지금까지의 비만과 전립선암과의 연관성에 대한 임상연구들은 대부분 서구인을 대상으로 시행되었으며 그 결과 또한 서로 상반되게 발표되고 있어 명확한 연관성을 밝히지 못하고 있는 실정이다. 이에 본 저자들은 한국인을 대상으로 비만과 전립선암과의 연관성을 알아보고자 2000년 1월부터 2005년 6월까지 영남대학교 의과대학 부속병원 비뇨기과에서 임상적으로 전립선암이 의심되어 경직장초음파유도하 전립선생검(transrectal ultrasound guided prostate biopsy)을 시행한 286명을 대상으로 환자들의 의무기록을 후향적으로 분석하여, 환자의 나이, 키, 몸무게, BMI, PSA, DRE, TRUS, 경직장초음파유도하 전립선생검, Gleason 점수, 임상적 병기 등을 비교, 분석하였다. 본 연구 결과에서는 BMI와 전립선암 발병률과는 연관성을 확인 할 수 없었으며, BMI와 임상적 병기와는 다소 연관성이 있는 것으로 나타났으나 통계적 유의성은 없었다. 이러한 비만 환자를 대상으로 한 연구에서는 비만의 기준에 따라서 큰 차이가 유발될 수 있으며, 비만 환자의 경우 전립선암 진단 및 치료 방법 등에 있어서 다양한 편견 및 오류가 작용할 수 있을 것으로 생각된다. 따라서, 비만과 전립선암과의 명확한 연관성을 확인하기 위해서는 향후 비만에 영향을 미칠 수 있는 다양한 인자와 호르몬 측정 및 BMI 이외의 여러 가지 비만 지수 등의 측정을 포함한 대규모 임상연구가 필요하리라 생각된다.