• Communications for Statistical Applications and Methods
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• 제14권1호
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• pp.205-213
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• 2007

In this paper, the normal mixture model subjected to general linear restriction for component-means based on linear regression is proposed, and its fitting method by EM algorithm and Lagrange multiplier is provided. This model is applied to gene clustering of microarray expression data, which demonstrates it has very good performances for real data set. This model also allows to obtain the clusters that an analyst wants to find out in the fashion that the hypothesis for component-means is represented by the design matrices and the linear restriction matrices.

• Journal of the Korean Statistical Society
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• 제25권1호
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• pp.81-94
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• 1996

This paper suggests a new criterion for testing the general linear hypothesis about coefficients in multivariate growth curve model. It is developed from a Bayesian point of view using the highest posterior density region methodology. Likelihood ratio test criterion(LRTC) by Khatri(1966) results as an approximate special case. It is shown that under the simple case of vague prior distribution for the multivariate normal parameters a LRTC-like criterion results; but the degrees of freedom are lower, so the suggested test criterion yields more conservative test than is warranted by the classical LRTC, a result analogous to that of Berger and Sellke(1987). Moreover, more general(non-vague) prior distributions will generate a richer class of tests than were previously available.

• Communications for Statistical Applications and Methods
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• 제10권3호
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• pp.1007-1015
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• 2003

In this paper we introduced a new score generating function for the rank dispersion function in a general linear model. Based on the new score function, we derived the null asymptotic theory of the rank-based hypothesis testing in a linear model. In essence we showed that several rank test statistics, which are primarily focused on our new score generating function and new dispersion function, are mainly distribution free and asymptotically converges to a chi-square distribution.

• 아태비즈니스연구
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• 제13권4호
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• pp.11-24
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• 2022

Purpose - The purpose of this study was to examine how job seekers' spec influence their actual employment especially focusing on the differentiating effects of applicants' specs depending on whether general or decent job employment. Design/methodology/approach - This study conducted analyses on 54,443 samples that incorporated data from the Graduates Occupational Mobility Survey for three years (2017-2019) collected by the Korea Employment Information Service. The linear probability model and logit model were used to examine the research questions. Findings - The results analyzed with the hierarchical regression model showed that most job seekers' specs were statistically significant in predicting employment status. Interestingly, there is a difference between the factors predicting employment for a general job and a decent job. This study suggests academic and practical implications for future research in the selection/ recruitment field by clarifying the critical factors to influence applicants' employment. Research implications or Originality The results of this study follow the screening hypothesis which explains that the applicants' specs have significant impacts on actual employment. Also, the dual labor market theory, which explains that applicants' specs differently affect actual employment between general and decent jobs, was reaffirmed.

• Communications for Statistical Applications and Methods
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• 제1권1호
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• pp.81-86
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• 1994

A Chi-square approximation to the distribution of product of independent Beta variates denoted by U is developed. The distribution is commonly used as a test criterion for the general linear hypothesis about the multivariate linear models. The approximation is obtained by fitting a logarithmic function of U to a Chi-square variate in terms of the first three moments. It is compared with the well known approximations due to Box(1949), Rao(1948), and Mudholkar and Trivedi(1980). It is found that the Chi-square approximation compares favorably with the other three approximations.

• Journal of applied mathematics & informatics
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• 제26권3_4호
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• pp.679-688
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• 2008

In multivariate regression analysis there exist many influence measures on the regression estimates. However it seems to be few of influence diagnostics on test statistics in hypothesis testing. Case-deletion approach is fundamental for investigating influence of observations on estimates or statistics. Tang and Fung (1997) derived single case-deletion of the Wilks' ratio, Lawley-Hotelling trace, Pillai's trace for testing a general linear hypothesis of the regression coefficients in multivariate regression. In this paper we derived more extended form of those measures to deal with joint influence among observations. A numerical example is given to illustrate the effect of joint influence on the test statistics.

• Journal of Biosystems Engineering
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• 제40권3호
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• pp.296-304
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• 2015

Purpose: The balance between miscanthus production and its cost effectiveness depends greatly on its moisture content during post processing. The objective of this research was to measure the moisture content using a non-destructive and non-contact methodology for in situ applications. Methods: The moisture content of comminuted miscanthus was controlled using a closed chamber, a humidifier, a precision weigher, and a real-time monitoring software developed in this research. A CMOS sensor equipped with $50{\times}$ magnifier lens was used to capture magnified images of the conditioned materials with moisture content level from 5 to 30%. The hypothesis is that when light is incident on the comminuted particles in an inclined manner, higher moisture content results in light being reflected with a higher intensity. Results: A linear regression analysis for an initiative hypothesis based on general histogram analysis yielded insufficient correlations with low significance level (<0.31) for the determination coefficient. A significant relationship (94% confidence level) was determined at level 108 in a reverse accumulative histogram proposed based on a revised hypothesis. A linear regression model with the value at level 108 in the reverse accumulative histogram for a magnified image as the independent variable and the moisture content of comminuted miscanthus as the dependent variable was proposed as the estimation model. The calibrated linear regression model with a slope of 92.054 and an offset of 32.752 yielded 0.94 for the determination coefficient (RMSE = 0.2%). The validation test showed a significant relationship at the 74% confidence level with RMSE 6.4% (n = 36). Conclusions: To compensate the inconsistent significance between calibration and validation, an estimation model robust against various systematic interferences is necessary. The economic efficiency of miscanthus, which is a promising energy resource, can be improved by the real-time measurement of its crucial material properties.

• Communications for Statistical Applications and Methods
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• 제15권2호
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• pp.265-271
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• 2008

It is commonly believed that diseases of human or economic traits of livestock are caused not by single genes acting alone, but multiple genes interacting with one another. This issue is difficult due to the limitations of parametric-statistic methods of gene effects. So we introduce multifactor-dimensionality reduction(MDR) as a methods for reducing the dimensionality of multilocus information. The MDR method is nonparametric (i. e., no hypothesis about the value of a statistical parameter is made), model free (i. e., it assumes no particular inheritance model) and is directly applicable to case-control studies. Application of the MDR method revealed the best model with an interaction effect between the SNPs, SNP1 and SNP3, while only one main effect of SNP1 was statistically significant for LMA (p < 0.01) under a general linear mixed model.

• 실천공학교육논문지
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• 제12권2호
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• pp.265-273
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• 2020

본 논문에서는 비전공자들을 위한 교양과목으로 적용할 수 있는 기초 데이터과학 실습 커리큘럼을 제안하고, 엑셀(스프레드시트) 데이터 분석 도구를 활용한 교육 방법을 제안하였다. 데이터 수집, 데이터 가공 및 데이터 분석을 위한 도구에는 엑셀, R, 파이썬, SQL(Structured Query Language) 등이 있다. R, 파이썬 및 SQL은 데이터 과학을 실습하는 데 있어, 프로그래밍 언어와 자료구조를 이해해야 한다. 반면에, 엑셀 도구는 비전공자들에게도 친숙한 데이터 분석도구로서, 프로그래밍 언어에 대한 학습 부담이 없다. 그리고 기초적인 데이터과학 실습을 엑셀로 진행하면, 데이터과학 이론을 습득하는 데 집중할 수 있는 장점이 있다. 본 논문에서는 한 학기 분량의 기초 데이터과학 실습 커리큘럼과 주별 엑셀 실습 내용을 제안하였다. 그리고, 교육 내용 실체를 실증하기위해, 엑셀 데이터분석 도구를 활용하여, 선형 회귀 분석(Linear Regression Analysis) 예제들을 제시하였다.

• 정보과학회 논문지
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• 제43권12호
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• pp.1396-1403
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• 2016

시간이 흐름에 따라 데이터 분포가 변하거나 관심 개념이 달라질 수 있는 스트리밍 데이터 분석에서 개념 변화에 적응해 나갈 수 있는 능력은 점층적 학습 과정에서 매우 중요하다. 이 논문에서는 개념 변화를 가진 스트리밍 데이터에서 적응적 점층적 분류기를 위한 일반화된 프레임워크를 제안한다. 분류기에 의해 예측되는 신뢰도 벡터와 클래스 라벨 벡터 사이의 거리를 이용하여 분류기 성능 패턴을 나타내는 분포를 구성하고 컨셉 변화에 대한 가설 검정을 수행한다. 추정되는 p-값을 이용하여 오래된 데이터에 대한 가중치를 자동으로 조정하여 분류기 업데이트에 이용한다. 제안된 방법을 두 가지 타입의 선형 판별 분류기에 적용한다. 컨셉 변화를 가진 스트리밍 데이터에 대한 실험 결과는 제안하는 적응적 점층적 학습 방법이 점층적 분류기의 예측 정확도를 크게 향상시킴을 입증한다.