• Title/Summary/Keyword: Variance Components

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ComputationalAalgorithm for the MINQUE and its Dispersion Matrix

  • Huh, Moon Y.
    • Journal of the Korean Statistical Society
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    • v.10
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    • pp.91-96
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    • 1981
  • The development of Minimum Norm Quadratic Unbiased Estimation (MINQUE) has introduced a unified approach for the estimation of variance components in general linear models. The computational problem has been studied by Liu and Senturia (1977) and Goodnight (1978, setting a-priori values to 0). This paper further simplifies the computation and gives efficient and compact computational algorithm for the MINQUE and dispersion matrix in general linear random model.

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An Efficient Method for Computing MINQUE Estimators in the Mixed Models

  • Lee, Jang-Taek;Kim, Byung-Chun
    • Journal of the Korean Statistical Society
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    • v.18 no.1
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    • pp.4-12
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    • 1989
  • An efficient method for computing minimum norm quadratic unbiased estimates (MINQUE) of variance components in the mixed model is developed. This computing algorithm which used W-matrix saves both storage usage and computing time.

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Analysis on Statistical Characteristic Changes due to the Analysis Periods of Non-Tidal Components Data in the East Coast of Korea (분석기간의 길이에 따른 동해안 비조석성분의 통계적 특성변화 분석)

  • Cho, Hong-Yeon;Jeong, Shin-Taek;Cho, Beom-Jun;Yun, Jong-Tae
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.19 no.2
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    • pp.151-161
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    • 2007
  • Statistical characteristic analysis was carried out using the non-tidal components computed by the harmonic analysis of the tidal elevation data in East coast. The tide gauging stations included in this study are the Sokcho, Mukho, Hupo, Pohang, Ulsan and Ulreungdo stations. In this study, the variance and skewness coefficient (SC) information changes, i.e., the max. value, min. value, mean and standard deviation of the variance and SC, are compared and analysed in detail by the various analysis periods increased from one year to the maximum available period. Based on the result of the statistical information (SI) range analysis, the minimum analysis period required in order to satisfy the confidence interval of the ${\pm}5%$ range of the variance and the ${\pm}0.1$ range of the SC is suggested as the 12 years, except the Ulreungdo stations. The auto-correlation and spectral density change patterns show the very similar shapes in every stations even though the absolute values are a little bit different each other.

Effects of Maternal Factors on Day-old Chick Body Weight and Its Relationship with Weight at Six Weeks of Age in a Commercial Broiler Line

  • Jahanian, Rahman;Goudarzi, Farshad
    • Asian-Australasian Journal of Animal Sciences
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    • v.23 no.3
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    • pp.302-307
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    • 2010
  • The present study aimed to investigate the effects of maternal factors on body weight at hatching (day-old) and at six weeks of age in a commercial broiler line. A total of 6,765 records on body weight at day-old (BWTDO) and 115,421 records on body weight at six weeks of age (BWT6W), originated from a commercial broiler line during 14 generations, were used to estimate genetic parameters related to the effects of maternal traits on body weight of chicks immediately after hatch or six weeks thereafter. The data were analyzed using restricted maximum likelihood procedure (REML) and an animal model with DFREML software. Direct heritability ($h^{2}{_a}$), maternal heritability ($h^{2}{_m}$), and maternal environmental variance as the proportions of phenotypic variance ($c^{2}$) for body weight at day-old were estimated to be 0.050, 0.351, and 0.173, respectively. The respective estimated values for body weight at six weeks of age were 0.340, 0.022, and 0.030. The correlation coefficient between direct and maternal genetic effects for six-week-old body weight was found to be -0.335. Covariance components and genetic correlations were estimated using a bivariate analysis based on the best model determined by a univariate analysis. Between weights at hatching and at six week-old, the values of -0.07, 0.53 and 0.47 were found for the direct additive genetic variance, maternal additive genetic variance and permanent maternal environmental variance, respectively. The estimated correlation between direct additive genetic effect influencing weight at hatch and direct additive maternal effect affecting weight at six weeks of age was -0.21, whereas the correlation value of 0.15 was estimated between direct additive maternal effect influencing weight at hatch and direct additive genetic effect affecting weight at six-week-old. From the present findings, it can be concluded that the maternal additive genetic effect observed for weight at six weeks of age might be a factor transferred from genes influencing weight at hatch to weight at six-week-old.

Scene Text Extraction in Natural Images Using Color Variance Feature (색 변화 특징을 이용한 자연이미지에서의 장면 텍스트 추출)

  • 송영자;최영우
    • Proceedings of the IEEK Conference
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    • 2003.07e
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    • pp.1835-1838
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    • 2003
  • Texts in natural images contain significant and detailed informations about the images. Thus, to extract those texts correctly, we suggest a text extraction method using color variance feature. Generally, the texts in images have color variations with the backgrounds. Thus, if we express those variations in 3 dimensional RGB color space, we can emphasize the text regions that can be hard to be captured with a method using intensity variations in the gray-level images. We can even make robust extraction results with the images contaminated by light variations. The color variations are measured by color variance in this paper. First, horizontal and vertical variance images are obtained independently, and we can fine that the text regions have high values of the variances in both directions. Then, the two images are logically ANDed to remove the non-text components with only one directional high variance. We have applied the proposed method to the multiple kinds of the natural images, and we confirmed that the proposed feature can help to find the text regions that can he missed with the following features - intensity variations in the gray-level images and/or color continuity in the color images.

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The Development and Validation of Eating Behavior Test Form for Infants and Young Children (영유아 식행동 검사도구 개발 및 타당도 검정)

  • Han, Youngshin;Kim, Su An;Lee, Yoonna;Kim, Jeongmee
    • Korean Journal of Community Nutrition
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    • v.20 no.1
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    • pp.1-10
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    • 2015
  • Objectives: This study was conducted to develop and validate Eating Behaviors Test form (EBT) for infants and young children, including eating behaviors of their parents and parental feeding practices. Methods: Draft version of EBT form was developed after a pretest on 83 mothers. It was consisted of 42 questions including 3 components; eating behavior of children, eating behavior of parents, and parental feeding practices. Using these questionnaires, the first survey was conducted on 320 infants and children, 1 to 6 year old, for exploratory factor analysis, and the second survey was collected on 731 infants and children for confirmatory factor analysis. Results: Exploratory factor analysis on 42 questions of EBT form resulted in 3 factor model for children's eating behavior, 3 factor model for parents' eating behavior, and 1 factor model for parental feeding practices. Three factors for children's eating behavior could be explained as follows; factor 1, pickiness (reliability ${\alpha}=0.89$; explanation of variance=27.79), factor 2, over activity (${\alpha}=0.80$, explanation of variance=16.51), and factor 3, irregularity (${\alpha}=0.59$, explanation of variance=10.01). Three factors for mother's eating behavior could be explained as follows; factor 1,irregularities (${\alpha}=0.73$, explanation of variance=21.73), factor 2, pickiness (${\alpha}=0.65$, explanation of variance= 20.16), and factor 3, permissiveness (${\alpha}=0.60$, explanation of variance=19.13). Confirmatory factor analysis confirmed an acceptance fit for these models. Internal consistencies for these factors were above 0.6. Conclusions: Our results indicated that EBT form is a valid tool to measure comprehensive eating and feeding behaviors for infants and young children.

ESTIMATES OF PHENOTYPIC AND GENETIC PARAMETERS FOR WEANING AND YEARLING WEIGHTS IN BALI BEEF CATTLE

  • Djegho, Y.;Blair, H.T.;Garrick, D.J.
    • Asian-Australasian Journal of Animal Sciences
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    • v.5 no.4
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    • pp.623-628
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    • 1992
  • Records on weaning (3803) and yearling weight (2990) of beef cattle (Bibos banteng) from the Bali Cattle Improvement Project were examined. A mixed model analysis involving all main non-genetic effects (village, year of birth, season of birth, age of dam, sex of calf, all significant interactions and age at weighing as a covariate) as fixed effects and sire nested within village as a random effect was undertaken. Variance components were estimated by Henderson's Method III. Paternal half-sib components of variance and covariance were used to estimate heritabilities of weaning and yearling weights, as well as their genetic and phenotypic correlations. Heritability estimates ($\pm$ standard error) obtained by Henderson's Method III for weaning and yearling weights were $.11{\pm}.03$ and $.13{\pm}.04$, respectively while the phenotypic and genetic correlations were estimated as .32 and $.64{\pm}.10$, respectively. The parameters estimated in this study were at the lower end of the range of reported values from various breeds. It is concluded that further information should be gathered to assist in estimating genetic parameters for other economic traits of Bali beef cattle and to provide more accurate estimates for weaning and yearling weights. These parameters should then be used to formulate a selection program to enable the genetic improvement of Bali Beef cattle.

Mixed-effects model by projections (사영에 의한 혼합효과모형)

  • Choi, Jaesung
    • The Korean Journal of Applied Statistics
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    • v.29 no.7
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    • pp.1155-1163
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    • 2016
  • This paper deals with an estimation procedure of variance components in a mixed effects model by projections. Projections are used to obtain sums of squares instead of using reductions in sums of squares due to fitting both the assumed model and sub-models in the fitting constants method. A projection matrix can be obtained for the residual model at each step by a stepwise procedure to test the hypotheses. A weighted least squares method is used for the estimation of fixed effects. Satterthwaite's approximation is done for the confidence intervals for variance components.

An Analysis of Genetic Variation and Divergence on Silk Fibre Characteristics of Multivoltine Silkworm (Bombyx mori L.) Genotypes

  • Kumaresan P.;Koundinya P. R.;Hiremath S. A.;Sinha R. K.
    • International Journal of Industrial Entomology and Biomaterials
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    • v.14 no.1
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    • pp.23-32
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    • 2007
  • The nature of genetic variation and diversity among the 65 multivoltine silkworm genotypes was evaluated for 16 post cocoon characters. The components of genetic variation revealed higher PCV (60.487%) and GCV (44.56%) for evenness (variation 1) followed by cohesion (PCV=55.38%, GCV=40.36%) and non-broken filament length (PCV=32.05%, GCV=31.28%). The higher heritability ($h^2$ in broad sense) was observed for boil-off loss (95.6%) followed by non-broken filament length (95.22%). The both genotypic and phenotypic correlation indicated significant positive correlation of filament length with non-broken filament length, silk recovery, raw silk, neatness, and low neatness; and negative correlation with denier, renditta and silk waste. The principal component analysis (PCA) revealed 75.381 % of total variance from the five principal components extracted. On the basis of Mahalonobis' $D^2$ values (Ward's minimum variance), the sixty-five multivoltine silkworm genotypes were classified in to 9 clusters with substantial inter and intra cluster distances. Number of genotypes included in different clusters varied from 3 to 17. The results indicated that the optimum distance obtained in cluster VII (15.059) along with higher cluster mean values especially for filament length, non broken filament length, renditta, silk recovery, silk waste, and raw silk emphasized the utilization of these genotypes in the conventional silkworm breeding programme for improvement of multivoltine silk fibre quality. The possibility of exploiting genetic variation in post cocoon traits for efficient breeding programme is discussed.

The analysis of random effects model by projections (사영에 의한 확률효과모형의 분석)

  • Choi, Jaesung
    • Journal of the Korean Data and Information Science Society
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    • v.26 no.1
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    • pp.31-39
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    • 2015
  • This paper deals with a method for estimating variance components on the basis of projections under the assumption of random effects model. It discusses how to use projections for getting sums of squares to estimate variance components. The use of projections makes the vector subspace generated by the model matrix to be decomposed into subspaces that are orthogonal each other. To partition the vector space by the model matrix stepwise procedure is used. It is shown that the suggested method is useful for obtaining Type I sum of squares requisite for the ANOVA method.