• 한국통계학회:학술대회논문집
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• 한국통계학회 2005년도 춘계 학술발표회 논문집
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• pp.227-231
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• 2005

민감한 모집단의 모수 추정 방법으로 확률화응답기법과 무응답을 고려한 직접조사 방법의 효율성을 비교 분석하였다.

• Communications for Statistical Applications and Methods
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• 제12권2호
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• pp.349-357
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• 2005

We suggest a functional technique with loess smoothing for estimating the change-point when there is one change-point in the mean model. The proposed change-point estimator is consistent. Simulation study shows a good performance of the proposed change-point estimator in comparison with other parametric or nonparametric change-point estimators.

• Journal of the Korean Statistical Society
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• 제5권1호
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• pp.19-28
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• 1976

In empirical study for fitting a multiple linear regression model for successive cross-sections data observed on the same set of independent variables over several time periods, one often faces the problem of poor $R^2$, the multiple coefficient of determination, which provides a standard measure of how good a specified regression line fits the sample data.

• Restorative Dentistry and Endodontics
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• 제20권2호
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• pp.768-779
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• 1995

This study was performed to investigate the effect of root canal shaping techniques on the change of the shape of prepared root canal. 40 mesiobuccal canals of recently extracted mandibular 1st and 2nd molars were divided into 4 groups and shaped by step-down/balanced force technique, step-down/step-back technique, step-back technique and conventional technique respectively. The change of the shape of root canal was traced by superimposing the radiographs obtained before and after shaping of each root canal. The results were as follows. 1. By the experimented techniques except conventional technique, the root canals were more shaped in convex side of apical area and in concave side of most curved and coronal area than in the other sides(P<0.05). By conventional technique, the root canals were more shaped in convex side than in convave side from apex to orifice(P<0.05). 2. By step-down/balanced force technique, the cancave sides at C and D points of proximal view and C point of clinical view were more shaped than the convex side(P<0.05). Through the entire canal, the concave side was more shaped than the convex side in proximal view(P<0.01). But there was no statistical difference between both sides in clinical view. 3. By step-down/step-back technique, the change of root canal shape was not statistically different in concave and convex sides at each point of both views(P>0.05). And through the entire canal in proximal view, there was no statistical difference in shaping percentage between both sides. But through the entire canal in clinical view, the concave side was more shaped than the convex side(P<0.1). 4. By step-back technique, the convex side at B point of clinical more shaped than the other sides(P<0.05). Through the entire canal in proximal and clinical views, there was no statistical difference in shaping percentage between both sides. 5. Comparing the total shaping percentage among techniques, that in conventional technique was the greatest numerically, and followed by the percentages in step-down/step-back, step-down/balanced force and step-back technique. But, in proximal view, shaping percentages were not statistically different among techniques(P>0.05, ANOVA test). In clinical view, shaping percentages in step-back and conventional techniques were statistically different(P<0.01, ANOVA test). * Proximal view: radiograph taken in mesiodistal direction. * Clincal view: radiograph taken in faciolingual direction. A point : 1mm point from radiographic apex B point : center point between A and C points C point : most curved point of root canal D point : center point between C point and canal oriffice.

• 응용통계연구
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• 제24권6호
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• pp.1161-1168
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• 2011

The approximation for the distribution functions of nonparametric test statistics is a significant step in statistical inference. A rank sum test for dispersions proposed by Ansari and Bradley (1960), which is widely used to distinguish the variation between two populations, has been considered as one of the most popular nonparametric statistics. In this paper, the statistical tables for the distribution of the nonparametric Ansari-Bradley statistic is produced by use of polynomially adjusted normal approximation as a semi parametric density approximation technique. Polynomial adjustment can significantly improve approximation precision from normal approximation. The normal-polynomial density approximation for Ansari-Bradley statistic under finite sample sizes is utilized to provide the statistical table for various combination of its sample sizes. In order to find the optimal degree of polynomial adjustment of the proposed technique, the sum of squared probability mass function(PMF) difference between the exact distribution and its approximant is measured. It was observed that the approximation utilizing only two more moments of Ansari-Bradley statistic (in addition to the first two moments for normal approximation provide) more accurate approximations for various combinations of parameters. For instance, four degree polynomially adjusted normal approximant is about 117 times more accurate than normal approximation with respect to the sum of the squared PMF difference.

• Nuclear Engineering and Technology
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• 제18권1호
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• pp.38-47
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• 1986

경수로심의 열 여유도를 분석하기 위하여 반응표면 및 Monte Carlo 방법을 이용하는 통계적 분석 방법이 제시되었다. 통계적인 열 여유도 분석 방법은 입력변수들의 불확실도를 확률론적으로 처리함으로써 열 여유도의 최적 평가를 수행한다. 이 방법은 원자력 1호기 정상상태의 원자로심 분석에 응용되었으며 또한 종래의 결정론적 방법 및 웨스팅하우스의 개선된 열설계 방법과도 비교되었다. 본 연구를 통하여 반응표면 분석 방법은 통계적인 열 여유도 분석에 유용함을 알 수 있었으며, 이 방법을 통한 열 여유도의 증가도 확인되었다.

• Communications for Statistical Applications and Methods
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• 제8권2호
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• pp.427-434
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• 2001

In this paper, we consider the nonparametric Bayesian approach to the multiple comparisons problem for I Poisson populations using Dirichlet process priors. We describe Gibbs sampling algorithm for calculating posterior probabilities for the hypotheses and calculate posterior probabilities for the hypotheses using Markov chain Monte Carlo. Also we provide a numerical example to illustrate the developed numerical technique.

• Journal of the Korean Statistical Society
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• 제29권2호
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• pp.137-153
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• 2000

Conjoint analysis is a widely-used statistical technique for measuring relative importance that individual place on the product's attributes. Despsite its practical importance, the complexity of conjoint model makes it difficult to analyze. In this paper, w consider a Bayesian approach using Jeffrey's noninformative prior. We derive Jeffrey's prior and give a sufficient condition under which the posterior derived from the Jeffrey's prior is paper.

• Communications for Statistical Applications and Methods
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• 제6권3호
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• pp.813-820
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• 1999

Supprot vector machine(SVM) is a new and very promising regression and classification technique developed by Vapnik and his group at AT&T Bell Laboratories. in this paper we provide a brief overview of SVM for regression. Furthermore we describe Bayesian model selection based on macKay's evidence framework for SVM regression.

• Communications for Statistical Applications and Methods
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• 제6권3호
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• pp.843-848
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• 1999

Support vector machine(SVM) is a new and very promising classification and regression technique developed by Bapnik and his group at AT&T Bell laboratories. However it has failed to establish itself as common machine learning tool. This is partly due to the fact that SVM is not easy to implement and its standard implementation requires the optimization package for quadratic programming. In this paper we present simple iterative Kernl Adatron algorithm for nonparametric regression which is easy to implement and guaranteed to converge to the optimal solution and compare it with neural networks and projection pursuit regression.