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34 results for “homogeneity”

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Research ArticleOpen accessEvery word in the titleGeometric Mean Type Measure of Marginal Homogeneity for Square Contingency Tables with Ordered CategoriesTomoyuki Nakagawa, Toshiki Takei, Aki Ishii, Sadao TomizawaFor square contingency tables, some studies have developed the weighted arithmetic mean type measure to represent the degree of departure from the marginal homogeneity. The present paper proposes (1) the cumulative partial marginal homogeneity model which has the weaker restriction than the marginal homogeneity model and (2) the measure to represent the degree of departure from the proposed model. The … …Journal of Mathematics and Statistics, Vol. 16, Issue 1 · 11 Aug 2020 · 6,620 accessesView PDFCite
Research ArticleOpen accessEvery word in the titleA HIGH B1 FIELD HOMOGENEITY GENERATION USING FREE ELEMENT ELLIPTICAL FOUR-COIL SYSTEMSidi M. Ahmed Ghaly, Sulaiman S. Al-SowayanDesign and testing of a prototype probe with high B1 magnetic field homogeneity that can be used for MRI is presented. It consists of four coaxial separately tuned rings of wire in a symmetric arrangement on an ellipsoidal surface. Compared to Helmholtz pair, which presents 2nd-order homogeneity, an improvement in field homogeneity is achieved, while preserving the simplicity of implementation. … …American Journal of Applied Sciences, Vol. 11, Issue 4 · 28 Jan 2014 · 7,019 accessesView PDFCite
Research ArticleOpen accessEvery word in the titleDecomposition of Marginal Homogeneity into Logit and Mean Ridits Equality for Square Contingency TablesKiyotaka Iki, Kouji Tahata, Sadao TomizawaProblem statement: For square contingency tables with ordered categories, if the Marginal Homogeneity (MH) model holds, then the probability that X selected at random from the row marginal distribution is less than Y selected independently at random from the column marginal distribution equals the probability that X is greater than Y. However, the converse does not hold. We are interested … …Journal of Mathematics and Statistics, Vol. 6, Issue 1 · 31 Mar 2010 · 7,297 accessesView PDFCite
Research ArticleOpen accessEvery word in the titleSpherical and Improved Helmholtz Coil with High B1 Homogeneity for Magnetic Resonance ImagingSidi M. Ahmed Ghaly, Khalid A. Al-Snaie, Obaidullah Khan MohammadSeveral types of volume RF coils such as Helmholtz pair have been used for Magnetic Resonance Imaging. However, the field uniformity of a coil has always been suffering from a critical issue in imaging accuracy. The presented work is a study and design of spherical and improved radiofrequency Helmholtz coil which produces a high B1 magnetic field homogeneity. This coil … …American Journal of Applied Sciences, Vol. 13, Issue 12 · 22 Dec 2016 · 8,159 accessesView PDFCite
Research ArticleOpen accessEvery word in the titleA Monte Carlo Study of Seven Homogeneity of Variance TestsHoward B. Lee, Gary S. Katz, Alberto F. RestoriProblem statement: The decision by SPSS (now PASW) to use the unmodified Levene test to test homogeneity of variance was questioned. It was compared to six other tests. In total, seven homogeneity of variance tests used in Analysis Of Variance (ANOVA) were compared on robustness and power using Monte Carlo studies. The homogeneity of variance tests were (1) Levene, (2) … …Journal of Mathematics and Statistics, Vol. 6, Issue 3 · 30 Sep 2010 · 8,103 accessesView PDFCite
Research ArticleOpen accessIn the keywordsTransformation Box-Cox for Stabilisation of Diversity in Group Random DesignYenny Sylvia, Djunaidy SantosoIn the field of research, there are a variety of statistical methods used. Hypothesis testing is one test that is often used to obtain the conclusions of the research conducted. One hypothesis testing that is often used is the testing of hypotheses through ANOVA (Box et al., 1978). However, in determining the validity of a hypothesis is obtained, there are … …Journal of Computer Science, Vol. 11, Issue 1 · 22 Sep 2014 · 7,175 accessesView PDFCite
Research ArticleOpen accessIn the keywordsA COEFFICIENT OF VARIABILITYManuel Martinez-PonsA coefficient of variability is described. It is shown that conducting all possible paired comparisons in a group of scores, the investigator can ascertain the group’s degree of variability as well as its converse, the group’s degree of homogeneity. The coefficient, useful in determining whether to divide a class into subgroups for the purpose of instruction, has the advantage that … …Journal of Mathematics and Statistics, Vol. 9, Issue 1 · 12 Apr 2013 · 7,107 accessesView PDFCite
Research ArticleOpen accessIn the keywordsDecompositions for Ordinal Quasi-Symmetry Model in Square Contingency Tables with Ordered CategoriesKouji Yamamoto, Satoru Shinoda, Sadao TomizawaProblem statement: For square contingency tables with ordered categories, this study considers four kinds of extensions of the marginal homogeneity model and gives decompositions for the ordinal quasi-symmetry model. The decompositions are extensions of some existing decompositions. Approach: This study gives a decomposition theorem that the ordinal quasi-symmetry model holds if and only if the quasi-symmetry model and the proposed … …Journal of Mathematics and Statistics, Vol. 7, Issue 4 · 28 Oct 2011 · 7,152 accessesView PDFCite
Research ArticleOpen accessIn the keywordsAdjustment of Peak Streamflows of a Tropical River for UrbanizationAta Amini, Thamer Mohammad Ali, Abdul Halim B Ghazali, Bujang Kim HuatPeak runoff from a catchment is influenced by many factors such as intensity and duration of rainfall, catchment topography, catchment shape, land use and other variables. For a particular catchment, landuse change and other human activities will alter the characteristic of catchment hydrograph. Problem statement: As a result of urbanization, the magnitude of floods occurring in a catchment increased. It … …American Journal of Environmental Sciences, Vol. 5, Issue 3 · 30 Jun 2009 · 7,546 accessesView PDFCite
Research ArticleOpen accessIn the keywordsA Computational Investigation into the Effect of Equal Channel Angular Processing on the Mechanical Properties of Severely Deformed ZK 60 Alloy Validated by ExperimentsOmar Almenaif, Yaqoub Alhumaydani, Mohammed Alnafisah et al.In this study, the response surface method and finite-element analysis were employed to model the ECAP processing for biodegradable magnesium alloy ZK 60 behavior at 250°C. Using Finite-Element (FE) analysis data was extracted and compared to the what was found by experimenting in order to investigate the effects of the ECAP processing parameters on the plastic deformation behavior of the … …American Journal of Engineering and Applied Sciences, Vol. 13, Issue 2 · 9 Jun 2020 · 7,238 accessesView PDFCite