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In the 1960s, W. B. Rosen conducted some remarkable experiments on unidirectional fibrous composites that gave seminal insights into their failure under increasing tensile load. These insights led him to a grid system where the nodes in the grid were ineffective length fibers and to model the composite as something he called a chain‐of‐bundles model (i.e., a series system of parallel subsystems of horizontal nodes that he referred to as bundles), where the chain fails when one of the bundles fails. A load‐sharing rule was used to quantify how the load is borne among the nodes. Here, Rosen's experiments are analyzed to determine the shape of a bundle. The analysis suggests that the bundles are not horizontal collection of nodes but rather small rectangular grid systems of nodes where the load‐sharing between nodes is local in its form. In addition, a Gibbs measure representation for the joint distribution of binary random variables is given. This is used to show how the system reliability for a reliability structure can be obtained from the partition function for the Gibbs measure and to illustrate how to assess the risk of failure of a bundle in the chain‐of‐bundle model. 相似文献
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Saralees Nadarajah 《Statistical Papers》2009,50(3):605-615
The Student’s t distribution has become increasingly prominent and is considered as a competitor to the normal distribution. Motivated by
real examples in Physics, decision sciences and Bayesian statistics, a new t distribution is introduced by taking the product of two Student’s t pdfs. Various structural properties of this distribution are derived, including its cdf, moments, mean deviation about the
mean, mean deviation about the median, entropy, asymptotic distribution of the extreme order statistics, maximum likelihood
estimates and the Fisher information matrix. Finally, an application to a Bayesian testing problem is illustrated. 相似文献
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编辑推荐：与《货币战争》相比,《货币战争2：金权天下》更系统、更完善、更严密,更趋向于现实。以三百年的历史纵深,全面阐述欧美主要金融势力集团的历史沿革,系统解析当今世界幕后主宰力量的运作和决策机制,清晰地勾勒出了错综复杂的国际金融势力集团的人脉关系图谱,并预言：世界单一货币将在2024年成为现实。 相似文献
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H. Dette A. Munk & T. Wagner 《Journal of the Royal Statistical Society. Series B, Statistical methodology》1998,60(4):751-764
The exact mean-squared error (MSE) of estimators of the variance in nonparametric regression based on quadratic forms is investigated. In particular, two classes of estimators are compared: Hall, Kay and Titterington's optimal difference-based estimators and a class of ordinary difference-based estimators which generalize methods proposed by Rice and Gasser, Sroka and Jennen-Steinmetz. For small sample sizes the MSE of the first estimator is essentially increased by the magnitude of the integrated first two squared derivatives of the regression function. It is shown that in many situations ordinary difference-based estimators are more appropriate for estimating the variance, because they control the bias much better and hence have a much better overall performance. It is also demonstrated that Rice's estimator does not always behave well. Data-driven guidelines are given to select the estimator with the smallest MSE. 相似文献
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Hugh Davies & Heather Joshi 《Journal of the Royal Statistical Society. Series A, (Statistics in Society)》1998,161(1):33-61
This paper uses data from the Family Expenditure Survey for five selected years between 1968 and 1990 to examine trends in the income distribution in the UK, highlighting the role of women's labour force participation and earnings. The increased labour force participation of married women (especially mothers of young children in the 1980s) made a greater contribution to the decline of the 'traditional' male breadwinner family than the increased number of lone parents. The lower half of the distribution of weekly earnings became increasingly dominated by women. Though women's weekly earnings remained low relative to men's, the increase in their participation meant that, over the period, an increased share of family income came from women's labour market income: in 1990 nearly a quarter of the income of families with children came from women's earnings. Women's earnings were an important factor in keeping families out of poverty. There was no trend towards increasing feminization of poverty over the sample period. Adult women were somewhat more likely to be poor than adult men were, but female-headed families were very much more likely to be in poverty, and much more dependent on state benefits, than male-headed families were. Women's increased role in the labour market affected those in male-headed families more than those in female-headed families. Alongside a broad tendency for women's earnings to reduce poverty and inequality, there is evidence that the female population has become more economically polarized. 相似文献