• Communications for Statistical Applications and Methods
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• 제19권5호
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• pp.721-729
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• 2012

Various methods control the influence of a covariate on a response variable. These methods are analysis of covariance(ANCOVA), RANK ANCOVA, ANOVA of (covariate-adjusted) residuals, and Kruskal-Wallis tests on residuals. Covariate-adjusted residuals are obtained from the overall regression line fit to the entire data set that ignore the treatment levels or factors. It is demonstrated that the methods on covariate-adjusted residuals are only appropriate when the regression lines are parallel and covariate means are equal for all treatments. In this paper, we proposed the new nonparametric method on the ANCOVA model, as applying joint placement in a one-way layout on residuals as described in Chung and Kim (2007). A Monte Carlo simulation study is adapted to compare the power of the proposed procedure with those of the previous procedure.

• Restorative Dentistry and Endodontics
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• 제43권4호
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• pp.43.1-43.7
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• 2018

• 응용통계연구
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• 제27권2호
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• pp.227-237
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• 2014

우리는 회귀분석에서 설명변수들 중 일부가 질적 변수인 경우 지시변수를 사용한다. 또한 공분산분석모형에서는 관심인자의 효과에 대한 유의성 검정시 연속변수인 공변수로 주어지는 방해인자를 미리 회귀분석으로 제거한다. 지시변수 사용 회귀모형이나 공분산분석모형을 위한 확증적 자료분석 전에 탐색적 자료분석의 한 수단으로서 자료깊이에 근거한 DD-plot을 이용하면 집단 간의 차이를 쉽게 알아볼 수 있다. 이 방법은 오차항의 통계모형을 가정하지 않으므로 유용한 탐색적 방법이 될 수 있다. 몇 가지 사례들을 통하여 DD-plot이 지시변수 사용 회귀모형이나 공분산분석모형을 위한 그래픽 탐색적 자료분석방법으로서 유용함을 보였다.

• Asia pacific journal of information systems
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• 제21권3호
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• pp.51-69
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• 2011

Security has been considered one of the most critical issues for managing IT resources in many organizations. Despite a growing interest and extensive research on security at various levels, little research has focused on the comparison of security knowledge levels between different cultures. The current study investigates and compares the security knowledge level between Korea and the U.S. Based on the literature review of spyware, Hofstede's cultural dimensions, and security knowledge, this study identifies three constructs (i.e., security familiarity, spyware awareness, and spyware knowledge) to examine the difference of security knowledge levels between Korea and the U.S. Six hundred ninety-six respondents from Korea and the U.S. participated in the survey, and an in-depth analysis based on analysis of covariance (ANCOVA) was carried out. The results show that the levels of security familiarity, spyware awareness, and spyware knowledge are significantly lower in Korea than in the U.S., as expected. These findings present a significant association between national culture and security knowledge, and the degree of individualism (or collectivism) plays an especially critical role in the perception of security. A number of implications for academia and practitioners emerge. Limitations and future research directions are discussed in the conclusion.

• Journal of Acupuncture Research
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• 제34권2호
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• pp.19-38
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• 2017

Objectives : This is a retrospective statistical analysis of the demographic and therapeutic characteristics influencing the continued improvement of symptoms in patients treated in 2014 for herniated lumbar discs at a Korean medicine hospital; thereby, providing clinical data to further improve medical services of Korean medicine. Methods : We investigated the demographic and therapeutic variables of all patients who were diagnosed with a herniated lumbar intervertebral disc and were hospitalized for more than 1 night at Dunsan Korean medicine hospital from January 1, 2014, to December 31, 2014. IBM SPSS 21.0 was used to conduct a logistic multiple regression analysis and a covariance analysis (ANCOVA) of the demographic and therapeutic variables collected from the electronic medical records and telephone surveys. Results : 1. A longer duration of hospitalization was significantly better for the maintenance of pain relief or a decrease in the pain after discharge. 2. Younger patients were significantly less likely to be treated with a Western medical treatment after discharge. 3. Most of the demographic and therapeutic variables were not statistically significant in regards to treatment for lower back pain since discharge. Conclusion : Some of the demographic and therapeutic variables had a positive effect on the prognosis at one year or greater in patients who received integrative Korean medical treatment for lumbar disc herniation. Continued and systematic research will be needed.

• Journal of applied mathematics & informatics
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• 제32권3_4호
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• pp.343-357
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• 2014

In many non-life insurance applications past data are given in a form known as the run-off triangle. Smoothing such data using parametric crisp regression models has long served as the basis of estimating future claim amounts and the reserves set aside to protect the insurer from future losses. In this article a fuzzy counterpart of the Hoerl curve, a well-known claim reserving regression model, is proposed to analyze the past claim data and to determine the reserves. The fuzzy Hoerl curve is more flexible and general than the one considered in the previous fuzzy literature in that it includes a categorical variable with multiple explanatory variables, which requires the development of the fuzzy analysis of covariance, or fuzzy ANCOVA. Using an actual insurance run-off claim data we show that the suggested fuzzy Hoerl curve based on the fuzzy ANCOVA gives reasonable claim reserves without stringent assumptions needed for the traditional regression approach in claim reserving.

• 문화기술의 융합
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• 제9권6호
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• pp.73-83
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• 2023

이 연구는 자기결정성이론에 기반한 게이미피케이션 이러닝 수업을 개발하고 그 효과를 확인하기 위한 서술적 조사연구이다. 자료수집 기간은 2023년 3월 1일부터 6월 15일까지 G광역시 G대학교 학생 59명을 대상으로 강좌 전후 수업참여도, 학습몰입도, 교수실재감을 조사하였다. 수집된 자료의 분석은 IBM SPSS/Win 26.0을 이용하였으며 서술통계, 분산분석(ANOVA), 공분산분석(ANCOVA)을 실시하였다. 연구결과 자기결정성 기반 게이미피케이션 수업은 수업에 참여한 학생들의 수업참여도, 학습몰입도, 교수실재감을 유의하게 향상시켰다(p<.05). 연구대상자의 일반적인 특성이 사후 검사의 결과에 영향을 미쳤는지 알아보기 위해 공분산분석(ANCOVA) 실시한 결과, 성별이 학습몰입도의 사후 검사 결과에 영향을 미쳤으며, 그 영향력은 7.9%였다. 이 연구결과를 바탕으로 자기결정성 기반 게이미피케이션 이러닝수업이 학습자의 수업참여도, 학습몰입도, 교수실재감에 효과적임을 알 수 있었다. 대학에서 이러닝의요구가 확대되고 있으므로 자기결정성 기반 게이미피케이션 이러닝 수업이 교양 및 전공영역에서 다양하게 개발되어야 할 것이다.

• Asian-Australasian Journal of Animal Sciences
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• 제30권6호
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• pp.765-772
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• 2017

Objective: This study examines the genetic factors influencing the phenotypes (four economic traits:oleic acid [C18:1], monounsaturated fatty acids, carcass weight, and marbling score) of Hanwoo. Methods: To enhance the accuracy of the genetic analysis, the study proposes a new statistical model that excludes environmental factors. A statistically adjusted, analysis of covariance model of environmental and genetic factors was developed, and estimated environmental effects (covariate effects of age and effects of calving farms) were excluded from the model. Results: The accuracy was compared before and after adjustment. The accuracy of the best single nucleotide polymorphism (SNP) in C18:1 increased from 60.16% to 74.26%, and that of the two-factor interaction increased from 58.69% to 87.19%. Also, superior SNPs and SNP interactions were identified using the multifactor dimensionality reduction method in Table 1 to 4. Finally, high- and low-risk genotypes were compared based on their mean scores for each trait. Conclusion: The proposed method significantly improved the analysis accuracy and identified superior gene-gene interactions and genotypes for each of the four economic traits of Hanwoo.

• Investigative Magnetic Resonance Imaging
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• 제19권1호
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• pp.10-18
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• 2015

Background and Purpose: The association between the low emotional regulation and the brain structural change of major depressive disorder (MDD) has been proposed, but the voxel-based morphometry (VBM) studies on female MDD are rare. The purpose of the present study was to show the regional volume changes of gray matter (GM) in female patients with MDD by optimized VBM. Methods: To control subjects homogeneity, twenty female MDD patients and age, sex matched 21 normal controls were included for the VBM analysis. To identify the change of regional gray matter volume (GMV), the optimized VBM was performed with T1 MRIs. The amounts of gray/white matter and intracranial cavity volumes (ICV) were measured. The analysis of covariance (ANCOVA) and partial correlation analyses covariate with age and ICV were applied for VBM. Results: The age and ICV distributions were similar between the two groups. In the ANCOVA, the total GMV of MDD was smaller than that of normal controls. In the VBM, regional GMV was relatively decreased in the limbic system (amygdalae, ambient gyri, hippocampi heads, subiculum, posterior parahippocampal gyri, pulvinar nuclei, dorsal posterior cingulate gyri, and left pregenual cingulate gyrus). The lingual gyri, short insular gyri, right fusiform gyrus, and right inferior frontal gyrus were also showed decreased regional GMV. Conclusion: The results of this study indicate that the female MDD is mainly associated with the structural deficits of the limbic system and limbic system related cortices, which were known to the center of emotions.

• Communications for Statistical Applications and Methods
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• 제24권3호
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• pp.241-254
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• 2017

Drawing a sample can be costly or time consuming in some studies. However, it may be possible to rank the sampling units according to some baseline auxiliary covariates, which are easily obtainable, and/or cost efficient. Ranked set sampling (RSS) is a method to achieve this goal. In this paper, we propose a modified approach of the RSS method to allocate units into an experimental study that compares L groups. Computer simulation estimates the empirical nominal values and the empirical power values for the test procedure of comparing L different groups using modified RSS based on the regression approach in analysis of covariance (ANCOVA) models. A comparison to simple random sampling (SRS) is made to demonstrate efficiency. The results indicate that the required sample sizes for a given precision are smaller under RSS than under SRS. The modified RSS protocol was applied to an experimental study. The experimental study was designed to obtain a better understanding of the pathways by which positive experiences (i.e., goal completion) contribute to higher levels of happiness, well-being, and life satisfaction. The use of the RSS method resulted in a cost reduction associated with smaller sample size without losing the precision of the analysis.