论文检索

精确平衡的有限总体样本：存在性与应用AI 解读

Abstract Samples selected from finite populations can rarely be exactly balanced, as sample selection is an integer problem and the balancing equations are strict equalities. Selecting a balanced sample is not a problem limited to survey sampling. It also applies to design of experiments, clinical trials, causality, exact inference, graph theory and network analysis. Building on Jean-Claude Deville’s foundational work, we explore conditions under which exact solutions are…

移动应用激活数据的捕获—再捕获方法AI 解读

This work is concerned with the analysis of marketing data on the activation of applications (apps) on mobile devices. Each application has a hashed identification number that is specific to the device on which it has been installed. This number can be registered by a platform at each activation of the application. Activations on the same device are linked together using the identification number. By focusing on activations that took place at a business location, one can…

踝关节旋转轴估计的方向统计模型AI 解读

This article is motivated by the estimation of the directions of the two rotation axes of the ankle. These axes carry information on individual ankles; they are useful in the construction of biomechanical models and the treatment of orthopedic problems. In biomechanics, the rotation axes of the ankle often are estimated using optimization techniques. This work investigates a statistical model for carrying out the estimation. The data set for analysis is a time-ordered…

依赖截断下的生存分布估计AI 解读

The product-limit estimator calculated from data subject to random left-truncation relies on the testable assumption of quasi-independence between the failure time and the truncation time. In this paper, we propose a model for a truncated sample of pairs (X-sub-i, Y-sub-i) satisfying Y-sub-i > X-sub-i. A possible dependency between the truncation time and the variable of interest is modelled with a parametric family of copulas. The model also features a distribution function…

群模型中位置与回归参数的 M 估计：Stiefel 流形案例AI 解读

We discuss here a general approach to the calculation of the asymptotic covariance of $M$-estimates for location parameters in statistical group models when an invariant objective function is used. The calculation reduces to standard tools in group representation theory and the calculation of some constants. Only the constants depend upon the precise forms of the density or of the objective function. If the group is sufficiently large this represents a major simplification…

用于刚体运动估计与几何质量检验的线性模型AI 解读

A geometrical method to assess the quality of a part is to sample points on the surface of the part and to bring an ideal computer representation of the part as close as possible to the sampled locations. The points are sampled with a coordinate measuring machine (CMM) that gives the coordinates, with respect to the machine's own three-dimensional system of axis, of the sampled locations. Computer-assisted design (CAD) gives the ideal representation of the part. The matching…

刚体运动估计的线性模型及其几何质量检验应用AI 解读

A geometrical method to assess the quality of a part is to sample points on the surface of the part and to bring an ideal computer representation of the part as close as possible to the sampled locations. The points are sampled with a coordinate measuring machine (CMM) that gives the coordinates, with respect to the machine's own three-dimensional system of axis, of the sampled locations. Computer-assisted design (CAD) gives the ideal representation of the part. The matching…

偏态分布下温莎化均值的统计性质AI 解读

Sampling properties of estimators of the mean of a positive random variable that Winsorize the largest or the two largest observations in the sample are investigated. Exact and approximate expressions for the mean squared errors of these estimators are derived. Optimal Winsorization schemes are obtained for various skewed distributions. Efficiency comparisons between the sample mean and Winsorized means are presented for several families of skewed distributions. A nearly…

摘要暂缺

比率估计量的抗离群值替代方法AI 解读

Many techniques have been suggested to lower the impact of outliers on sample survey estimates. Outliers can be downweighted by winsorization; that is, by replacing extreme data points by a data-dependent or a predetermined value before calculating estimates. Another approach is to reduce the weight of outliers, from the inverse sampling fraction to 1, in the estimation of population characteristics. In this article the problem of estimating the population mean using…

比率估计量的抗异常值替代方法AI 解读

Many techniques have been suggested to lower the impact of outliers on sample survey estimates. Outliers can be downweighted by winsorization; that is, by replacing extreme data points by a data-dependent or a predetermined value before calculating estimates. Another approach is to reduce the weight of outliers, from the inverse sampling fraction to 1, in the estimation of population characteristics. In this article the problem of estimating the population mean using…

高集中度 Fisher–von Mises 分布下的球面回归AI 解读

Spherical regression studies models which postulate that the unit vector $v$ is equal to an unknown rotation $P$ of the unit vector $u$ "plus" an experimental error. The case where the experimental errors follow a Fisher-von Mises distribution with a large concentration parameter $\kappa$ is considered in this work. Asymptotic $(\kappa \rightarrow \infty)$ inferential procedures for $P$ are proposed when $n$, the sample size, is fixed. Diagnostic methods for spherical…

超球面上对称分布的信息矩阵AI 解读

A general definition of symmetry for a directional model is given. Then the information matrix for the parameters indexing a symmetric density is shown to be block-diagonal: one block for the location and one block for the shape. This result is used to construct an algorithm for the efficient estimation of the parameters. Examples are given; a new symmetric distribution, the $FB_6$ is introduced; it generalizes the classical distributions on the hypersphere.

相关单位向量的对称分布AI 解读

This paper introduces several notions of symmetry for the joint distribution of two dependent unit vectors. Bivariate generalizations of $\mathscr{L}$-symmetry (Rivest, 1984) and rotational symmetry are introduced. If the joint distribution of two unit vectors is at least $\mathscr{L}$-symmetric the information matrix for the parameters indexing it is shown to have a simple shape.

双变量圆周数据的若干统计方法AI 解读

Summary A function of the smallest singular value of the cross product matrix between two circular unit vectors is suggested as a measure of correlation. It possesses most of the desirable properties for a correlation coefficient given by Jupp and Mardia (1980). The concept of cluster dependence is introduced. A good predictor of one unit vector given the other is shown to depend on the type of dependence observed. The wrapped bivariate normal is characterized.