The Experts below are selected from a list of 260166 Experts worldwide ranked by ideXlab platform
Satoshi Tonai - One of the best experts on this subject based on the ideXlab platform.
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parametric and non parametric statistical approaches to the determination of paleostress from dilatant fractures application to an early miocene dike swarm in central japan
Tectonophysics, 2013Co-Authors: Katsushi Sato, Atsushi Yamaji, Satoshi TonaiAbstract:Abstract Several methods have been proposed for determining paleostress states from orientations of dilatant fractures such as dikes and veins. Recently a stochastic inversion method was invented to objectively estimate the principal stress axes and the stress ratio. Whether a fracture is dilated or not is controlled by the balance of the fluid pressure and the normal stress acting on it. The magnitude of normal stress depends on the fracture orientation, which causes anisotropic orientation Distribution of dilatant fractures. The inversion method assumes that the orientation Distribution of fractures can be approximated by a Bingham Distribution, an exponential probability Distribution on the unit sphere, of which symmetric axes are interpreted as the principal stress axes. However, it is unknown if the exponential type of Distribution function is suitable or not. Here, we examine the Distribution functions and propose two improved methods. One method uses the shifted power-law function as the Shape of probability Distribution, which is more flexible than the Bingham Distribution and is applicable to various Shapes of orientation Distributions. Furthermore, an index of the driving fluid pressure can be estimated with a confidence interval. The other is a non-parametric (Distribution-free) method, which can avoid the a priori assumption on the Shape of Distribution function without significantly losing accuracy or precision. The new methods were applied to an Early Miocene dike swarm formed during the back-arc opening of the Japan Sea. A normal-faulting stress regime with the minimum principal stress axis trending roughly perpendicular to the arc was obtained from the dikes. A moderately high stress ratio and a high fluid pressure were also estimated.
Fan Jia - One of the best experts on this subject based on the ideXlab platform.
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a new procedure to test mediation with missing data through nonparametric bootstrapping and multiple imputation
Multivariate Behavioral Research, 2013Co-Authors: Fan JiaAbstract:This article proposes a new procedure to test mediation with the presence of missing data by combining nonparametric bootstrapping with multiple imputation (MI). This procedure performs MI first and then bootstrapping for each imputed data set. The proposed procedure is more computationally efficient than the procedure that performs bootstrapping first and then MI for each bootstrap sample. The validity of the procedure is evaluated using a simulation study under different sample size, missing data mechanism, missing data proportion, and Shape of Distribution conditions. The result suggests that the proposed procedure performs comparably to the procedure that combines bootstrapping with full information maximum likelihood under most conditions. However, caution needs to be taken when using this procedure to handle missing not-at-random or nonnormal data.
Sabine Kroger - One of the best experts on this subject based on the ideXlab platform.
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flexible approximation of subjective expectations using probability questions
Journal of Business & Economic Statistics, 2012Co-Authors: Charles Bellemare, Luc Bissonnette, Sabine KrogerAbstract:We propose a flexible method to approximate the subjective cumulative Distribution function of an economic agent about the future realization of a continuous random variable. The method can closely approximate a wide variety of Distributions while maintaining weak assumptions on the Shape of Distribution functions. We show how moments and quantiles of general functions of the random variable can be computed analytically and/or numerically. We illustrate the method by revisiting the determinants of income expectations in the United States. A Monte Carlo analysis suggests that a quantile-based flexible approach can be used to successfully deal with censoring and possible rounding levels present in the data. Finally, our analysis suggests that the performance of our flexible approach matches that of a correctly specified parametric approach and is clearly better than that of a misspecified parametric approach.
Katsushi Sato - One of the best experts on this subject based on the ideXlab platform.
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parametric and non parametric statistical approaches to the determination of paleostress from dilatant fractures application to an early miocene dike swarm in central japan
Tectonophysics, 2013Co-Authors: Katsushi Sato, Atsushi Yamaji, Satoshi TonaiAbstract:Abstract Several methods have been proposed for determining paleostress states from orientations of dilatant fractures such as dikes and veins. Recently a stochastic inversion method was invented to objectively estimate the principal stress axes and the stress ratio. Whether a fracture is dilated or not is controlled by the balance of the fluid pressure and the normal stress acting on it. The magnitude of normal stress depends on the fracture orientation, which causes anisotropic orientation Distribution of dilatant fractures. The inversion method assumes that the orientation Distribution of fractures can be approximated by a Bingham Distribution, an exponential probability Distribution on the unit sphere, of which symmetric axes are interpreted as the principal stress axes. However, it is unknown if the exponential type of Distribution function is suitable or not. Here, we examine the Distribution functions and propose two improved methods. One method uses the shifted power-law function as the Shape of probability Distribution, which is more flexible than the Bingham Distribution and is applicable to various Shapes of orientation Distributions. Furthermore, an index of the driving fluid pressure can be estimated with a confidence interval. The other is a non-parametric (Distribution-free) method, which can avoid the a priori assumption on the Shape of Distribution function without significantly losing accuracy or precision. The new methods were applied to an Early Miocene dike swarm formed during the back-arc opening of the Japan Sea. A normal-faulting stress regime with the minimum principal stress axis trending roughly perpendicular to the arc was obtained from the dikes. A moderately high stress ratio and a high fluid pressure were also estimated.
Charles Bellemare - One of the best experts on this subject based on the ideXlab platform.
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flexible approximation of subjective expectations using probability questions
Journal of Business & Economic Statistics, 2012Co-Authors: Charles Bellemare, Luc Bissonnette, Sabine KrogerAbstract:We propose a flexible method to approximate the subjective cumulative Distribution function of an economic agent about the future realization of a continuous random variable. The method can closely approximate a wide variety of Distributions while maintaining weak assumptions on the Shape of Distribution functions. We show how moments and quantiles of general functions of the random variable can be computed analytically and/or numerically. We illustrate the method by revisiting the determinants of income expectations in the United States. A Monte Carlo analysis suggests that a quantile-based flexible approach can be used to successfully deal with censoring and possible rounding levels present in the data. Finally, our analysis suggests that the performance of our flexible approach matches that of a correctly specified parametric approach and is clearly better than that of a misspecified parametric approach.