• 제목/요약/키워드: Variance component

검색결과 509건 처리시간 0.027초

Tilted beta regression and beta-binomial regression models: Mean and variance modeling

  • Edilberto Cepeda-Cuervo
    • Communications for Statistical Applications and Methods
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    • 제31권3호
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    • pp.263-277
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    • 2024
  • This paper proposes new parameterizations of the tilted beta binomial distribution, obtained from the combination of the binomial distribution and the tilted beta distribution, where the beta component of the mixture is parameterized as a function of their mean and variance. These new parameterized distributions include as particular cases the beta rectangular binomial and the beta binomial distributions. After that, we propose new linear regression models to deal with overdispersed binomial datasets. These new models are defined from the proposed new parameterization of the tilted beta binomial distribution, and assume regression structures for the mean and variance parameters. These new linear regression models are fitted by applying Bayesian methods and using the OpenBUGS software. The proposed regression models are fitted to a school absenteeism dataset and to the seeds germination rate according to the type seed and root.

Discriminant Analysis of Marketed Liquor by a Multi-channel Taste Evaluation System

  • Kim, Nam-Soo
    • Food Science and Biotechnology
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    • 제14권4호
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    • pp.554-557
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    • 2005
  • As a device for taste sensation, an 8-channel taste evaluation system was prepared and applied for discriminant analysis of marketed liquor. The biomimetic polymer membranes for the system were prepared through a casting procedure by employing polyvinyl chloride, bis (2-ethylhexyl)sebacate as plasticizer and electroactive materials such as valinomycin in the ratio of 33:66:1, and were separately attached over the sensitive area of ion-selective electrodes to construct the corresponding taste sensor array. The sensor array in conjunction with a double junction reference electrode was connected to a high-input impedance amplifier and the amplified sensor signals were interfaced to a personal computer via an A/D converter. When the signal data from the sensor array for 3 groups of marketed liquor like Maesilju, Soju and beer were analyzed by principal component analysis after normalization, it was observed that the 1st, 2nd and 3rd principal component were responsible for most of the total data variance, and the analyzed liquor samples were discriminated well in 2 dimensional principal component planes composed of the 1st-2nd and the 1st-3rd principal component.

주성분 분석을 이용한 농업생산기반의 재해 취약성 평가에 관한 연구 (A Study on the Vulnerability Assessment for Agricultural Infrastructure using Principal Component Analysis)

  • 김성재;김성민;김상민
    • 한국농공학회논문집
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    • 제55권1호
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    • pp.31-38
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    • 2013
  • The purpose of this study was to evaluate climate change vulnerability over the agricultural infrastructure in terms of flood and drought using principal component analysis. Vulnerability was assessed using vulnerability resilience index (VRI) which combines climate exposure, sensitivity, and adaptive capacity. Ten flood proxy variables and six drought proxy variables for the vulnerability assessment were selected by opinions of researchers and experts. The statistical data on 16 proxy variables for the local governments (Si, Do) were collected. To identify major variables and to explain the trend in whole data set, principal component analysis (PCA) was conducted. The result of PCA showed that the first 3 principal components explained approximately 83 % and 89 % of the total variance for the flood and drought, respectively. VRI assessment for the local governments based on the PCA results indicated that provinces where having the relatively large cultivation areas were categorized as vulnerable to climate change.

Application of varimax rotated principal component analysis in quantifying some zoometrical traits of a relict cow

  • Pares-Casanova, P.M.;Sinfreu, I.;Villalba, D.
    • 대한수의학회지
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    • 제53권1호
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    • pp.7-10
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    • 2013
  • A study was conducted to determine the interdependence among the conformation traits of 28 "Pallaresa" cows using principal component analysis. Originally 21 body linear measurements were obtained, from which eight traits are subsequently eliminated. From the principal components analysis, with raw varimax rotation of the transformation matrix, two principal components were extracted, which accounted for 65.8% of the total variance. The first principal component alone explained 51.6% of the variation, and tended to describe general size, while the second principal component had its loadings for back-sternal diameter. The two extracted principal components, which are traits related to dorsal heights and back-sternal diameter, could be considered in selection programs.

Effect of Bias on the Pearson Chi-squared Test for Two Population Homogeneity Test

  • Heo, Sunyeong
    • 통합자연과학논문집
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    • 제5권4호
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    • pp.241-245
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    • 2012
  • Categorical data collected based on complex sample design is not proper for the standard Pearson multinomial-based chi-squared test because the observations are not independent and identically distributed. This study investigates effects of bias of point estimator of population proportion and its variance estimator to the standard Pearson chi-squared test statistics when the sample is collected based on complex sampling scheme. This study examines the effect under two population homogeneity test. The standard Pearson test statistic can be partitioned into two parts; the first part is the weighted sum of ${\chi}^2_1$ with eigenvalues of design matrix as their weights, and the additional second part which is added due to the biases of the point estimator and its variance estimator. Our empirical analysis shows that even though the bias of point estimator is small, Pearson test statistic is very much inflated due to underestimate the variance of point estimator. In the connection of design-based variance estimator and its design matrix, the bigger the average of eigenvalues of design matrix is, the larger relative size of which the first component part to Pearson test statistic is taking.

The Variation of Winter Buds among 10 Selected Populations of Kalopanax septemlobus Koidz. in Korea

  • Kim, Sea-Hyun;Ahn, Young-sang;Jung, Hyun-Kwon;Jang, Yong-Seok;Park, Hyung-Soon
    • Plant Resources
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    • 제5권3호
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    • pp.214-223
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    • 2002
  • The objective of this study was to understand the conservation of gene resources and provide information for mass selection' of winter bud characters among the selected populations of Kalopanax septemlobus Koidz using analysis of variance(ANOVA) tests. The obtained results are shown below; 1. Ten populations of K. septemlobus were selected for the study of the variation of winter bud characters in Korea. The results of the analysis of variance(ANOVA) tests shows that there were statistically significant differences in all of the winter bud characters among those populations. 2. Correlation analysis shows that width between Height and DBH(Diameter at breast height) characters have negative relationship with all of the characters, as ABL(Apical branch length), ABW(Apical branch width), AWBL(Apical branch winter bud length), AWBW(Apical branch winter bud width), ABT(Apical branch No. of thorns), ABLB(Apical branch No. of lateral bud) and LBL(Lateral branch length), LBW(Lateral branch width), LBT(Lateral branch No. of thorns), LBLB(Lateral branch No. of lateral bud). 3. The result of principal component analysis(PCA) for winter buds showed that the first principal components(PC' s) to the fourth principal component explains about 78% of the total variation. The first principal component(PC) was correlated with AWBW, LWBW, and LBL and the ratio of ABL/ABW and LBL/LBW out of 16 winter bud characters. The second principal component correlated with ABL, ABW, ABLB, LWBL(Lateral branch winter bud length), and LBW and the ratio of AWBL/AWBW. The third principal component correlated with ABL, ABW, LWBL, LBL, and the ratio of LBL/LBW. The fourth principal component correlated with LBL and the ratio of LWBL/LWBW(Lateral branch winter bud width), LBL/LBW. Therefore, these characters were important to analysis of the variation for winter bud characters among selected populations of K. septemlobus in Korea. 4. Cluster analysis using the average linkage method based on 10 selected populations for the 16 winter bud characters of K. septemlobus in Korea showed a clustering into two groups by level of distance 1.1(Fig. 3). As can be seen in Fig. 3, Group I consisted of three areas(Mt. Sori, Mt. Balwang and Mt. Worak) and Group Ⅱ contisted of seven areas(Suwon, Mt. Chuwang, Mt. Kyeryong, Mt. Kaji, Mt. Jiri, Muan, and Mt. Halla). The result of cluster analysis for winter bud characters corresponded well with principal component analysis, as is shown in Fig. 2.

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젖소집단의 산차에 따른 체세포점수의 환경효과 및 분산성분 추정 (Estimation of Variance Component and Environment Effects on Somatic Cell Scores by Parity in Dairy Cattle)

  • 조광현;나승환;서강석;김시동;박병호;이영창;박종대;손삼규;최재관
    • Journal of Animal Science and Technology
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    • 제48권1호
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    • pp.39-48
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    • 2006
  • 본 연구는 1999년 1월부터 2004년 12월까지의 체세포점수의 검정일 자료를 이용하여 124,635개의 초산자료와 134,308개의 2산자료, 37,412개의 3산자료, 41787개의 4산자료, 37412개의 5산 자료를 이용하였다. 분석에 사용된 방법은 체세포 점수에 영향을 미치는 분만연도, 연령, 비유단계, 산차, 계절의 효과를 추정하기 위하여 GLM을 이용하여 최소자승법으로 분석하였으며, 검정일 모형을 이용한 분산성분 추정은 EM-REML 분석방법을 전산 프로그램한 REMLF90을 이용하였다. 각 산차별로 연령에 대한 효과는 연령이 낮은 군에서 체세포 점수가 낮게 나타났으며, 연령이 높은 군에서는 다소 높게 나타났다. 비유단계별 효과는 1산과 2산에서는 비유초기에서 체세포 점수가 낮게 나타났으며 비유말기에 3.151, 3.696로 높은 체세포 점수를 나타났으나, 3산, 4산, 5산에서는 비유중기에 높은 체세포 점수를 나타내었으며, 대체로 피크기에 체세포 점수가 높게 나타나는데 4산과 5산에서는 비유말기에 체세포 점수가 낮게 나타났다. 분만계절별 환경효과는 1산~5산 모두 대체로 9~11월에 체세포 점수가 낮게 나타났으며, 대체로 유량이 낮게 추정되는 6~8월 사이에는 체세포 점수가 대체로 높게 나타났다. 각 산차별 유전력은 1산에서 5산까지 각각 0.05, 0.09, 0.10, 0.05, 0.05를 나타냈으며, 유전분산값은 비유초기의 경우 2, 3, 5산에서 높게 나타났으며, 1산과 4산의 경우는 대체로 낮게 추정되었다.

통증 평가도구 개발을 위한 기초조사 (A Preliminary Study for Development of a Pain Questionnaire)

  • 이충휘
    • The Journal of Korean Physical Therapy
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    • 제1권1호
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    • pp.63-72
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    • 1989
  • The present study was designed to investigate the general characteristics of pain patients and to analyze the properties of Korean pain expression terms as a preliminary step in the development of a pain questionnaire. Questionnaires were administered to 73 adult patients (53 males, 20 females) with knee, ankle, neck, low back, and shoulder pain. The mean duration of pain was 16.2 months (SE=3.3). The results were as fellows : 1. The data show that there are over 30 words in the Korean language to describe the varieties of pain experience even within this small sample. 2, There was low significant relationship between present pain intensity using visual analogue scale and the selected numbers of pain words from the pain questionnaire (p<.01). 3. In order to separate basic factors, a principal component analysis with varimax rotation was performed. The principal component analysis produced 8 factors. The proportion of variance explained by these factors was $71.0\%$. The first factor accounting $26.8\%$ of the variance was labeled 'cruelty and fear related pain' ; second 'pain produced from deep tissue' : third 'skin-punctuating related pain' ; and fourth 'miscellaneous and complicated pain'. Results of this study might be utilitzed in developing a pain questionnaire for pain patients.

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주성분 분석을 이용한 홍삼의 내부품질과 자기공명특성 분석 (Analysis of Internal Quality and Magnetic Resonance Characteristics of Red Ginseng Using PCA)

  • 김성민;김철수
    • Journal of Biosystems Engineering
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    • 제28권3호
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    • pp.261-268
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    • 2003
  • Ten MHz pulsed NMR spectrometer was used to measure the magnetic resonance characteristics of Korean red ginseng. The difference in the internal structures of good and bad red ginsengs was examined by their NMR characteristics. Average values of $T_1$ and free induction decay(FID) ratios of under grade Korean red ginseng were the highest among the three groups categorized as normal, medium and under grades Korean red ginseng and average values of $T_2$ and $T_2$$^{*}$ of them were the lowest among the three groups. Principal component analysis(PCA) was used to observe the contribution of measured NMR values to the grade of Korean red ginseng. The measured $T_1$, $T_2$, $T_2$$^{*}$ and FID ratio of 79 Korean red ginsengs classified as normal grade, medium grade and under grade were examined using PCA analysis. Cumulative variance of PC1 through PC3 occupied more than 90% of total variance at first and second NMR measurement. Plots of PC scores for the most important PCs showed that normal red ginseng samples were distributed around the left region of PC1 axis and most of the undergrade red ginseng samples were scattered around the right region of PC1 axis.

여대생의 건강 관련 삶의 질 영향 요인 (Factors Affecting Health-related Quality of Life in Women Undergraduates)

  • 차보경
    • 기본간호학회지
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    • 제20권4호
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    • pp.400-409
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    • 2013
  • Purpose: This study was conducted to define factors influencing health-related quality of life (HRQOL) in women undergraduates. Independent variables of physical activity, attitude to eating, satisfaction with body shape, stress and self-esteem were used to predict HRQOL. Method: Data were analyzed using the SPSS/WIN 20.0 program for descriptive statistics, Pearson correlation coefficients and stepwise multiple regression. Participants were 245 women undergraduates who were recruited from July to September 2012. Result: The mean for the physical component summary (PCS) of HRQOL was 73.89, and for the mental component summary (MCS) was 68.45. There were significant correlations between attitude to eating, satisfaction with body shape, stress, self-esteem and the two components of HRQOL. The groups with minimal or health enhancing activity were significantly higher in PCS and MCS than the inactivity group. Stepwise multiple regression analysis indicated that 35% of the variance in PCS was significantly accounted for by self-esteem, perceived stress, attitude to eating, and physical activity, and 45% of the variance in MCS was significantly accounted for by perceived stress, self-esteem, attitude to eating, and satisfaction with body shape. Conclusion: The results indicate that these factors influencing HRQOL should be considered when developing programs to improve HRQOL for women undergraduates.