Longitudinal shape analysis by using the spherical coordinates

One of the important topics in morphometry that received high attention recently is the longitudinal analysis of shape variation. According to Kendall's definition of shape, the shape of object appertains on non-Euclidean space, making the longitudinal study of configuration somehow difficult. However, to simplify this task, triangulation of the objects and then constructing a non-parametric regression-type model on the unit sphere is pursued in this paper. The prediction of the configurations in some time instances is done using both properties of triangulation and the size of great baselines. Moreover, minimizing a Euclidean risk function is proposed to select feasible weights in constructing smoother functions in a non-parametric smoothing manner. These will provide some proper shape growth models to analysis objects varying in time. The proposed models are applied to analysis of two real-life data sets.     

Fluctuating capacity of policy advice in Russia: testing theory in developing country context

ABSTRACT

Theories and concepts developed and empirically tested in the context of North American and Western European countries do not always easily transfer to another political landscape. The concept of “policy advisory system” is not an exception. On the one hand, policy processes and policy styles are not unique for each country; therefore, some generalizations can be made. On the other hand, studding particularities of policy process in a specific country can enrich theories, developed for general cases. Applying existing theories to a new context also goes a long way in verification and potential falsification – the fundamental requirement for a scientific process. This article aims to contribute to the debate on the topic of policy advisory system by comparing the development of three policies in Russia, each involving policy advisors to some extent. Based on this analysis, lessons are drawn regarding the conditions under which policy advisors can impact policy changes in an environment, alternative to “western.”     

基于一种半开式滑槽球副的3-PSP并联平台设计

提出在并联机构中应用一种1移动3转动半开式滑槽球副结构,该运动副将1个移动副和1个球副集成为一个复合的运动副,可以缩短并联机构中支链的尺寸链,有助于提高并联机构精度。基于半开式滑槽球副设计了一种3自由度(3-DOF)PSP三轴并联平台,通过对此机构进行的运动分析和支链的精度分析,导出各个支链的逆解方程,同时根据影响支链运动精度的各个因素给出支链系统误差的线性补偿方程,证明此并联机构具有易于控制、运动精度高的优势。     

Statistical techniques in stereology

Stereology typically concerns estimation of properties of a geometric structure from plane section information. This paperprovides a brief review of some statistical aspects of this rapidly developing field, with some reference to applications in the earth sciences. After an introductory discussion of the scope of stereology, section 2 briefly mentions results applicable when no assumptions can be made about the stochastic nature of the sampled matrix, statistical considerations then arising solelyfrom the ‘randomness’ of the plane section. The next two sections postulate embedded particles of specific shapes, the particular case of spheres being discussed in some detail.

References are made to results for ‘thin slices’ and other prob-ing mechanisms. Randomly located convex particles, of otherwise arbitrary shape, are discussed in section 5 and the review concludes with a specific application of stereological ideas to some data on neolithic mining.     

A GENERALIZED EMERSON RECURRENCE RELATION

The Emerson (1968, Biometrics 24 , 695–701) recurrence relation has many important applications in statistics. However, the original derivation applied only to discrete distributions. In the following, a simple derivation is given that generalizes the Emerson recurrence relation to any distribution for which the necessary expectations exist. A modern application is outlined.     

Estimation of scale parameters in mixture distributions

Simultaneous estimation of scale parameters is considered in mixture distributions under squared-error loss. A general class of estimators is obtained which dominates the componentwise best multiple estimators and the moment estimators. As special cases, improved estimators are obtained for the multivariate t-distribution and the p-variate Lomax distribution.     

弱位相光栅的自成像研究

本文从理论上对球面波照明弱位相光栅时的自成像现象进行了研究，发现当相对位相分布（x）＜＜1弧度时，位相光栅也存在自成像现象。     

论北宋词的女性化特征演进史

本文在阐释了词的女性化特征的前提下,主要描述了北宋词的女性化特征演进历程。笔者先对北宋词史链条上的每一个词人的风格进行个案梳理,然后用史学模式和史学思维重新构建北宋词女性化特征发展流变的整体框架。柳永、东坡、美成等的个案研究意在梳理出词人之间在词风上互相传承的关系,以此归结出词的本质属性--女性化特征的演进过程。     

Directional mixture models and optimal estimation of the mixing density

The authors develop consistent nonparametric estimation techniques for the directional mixing density. Classical spherical harmonics are used to adapt Euclidean techniques to this directional environment. Minimax rates of convergence are obtained for rotation ally invariant densities verifying various smoothness conditions. It is found that the differences in smoothness between the Laplace, the Gaussian and the von Mises‐Fisher distributions lead to contrasting inferential conclusions.     

GTEM Cell的坐标变换分析

文献［１］提出用坐标变换将ＧＴＥＭｃｅｌｌ变换成均匀矩形偏心同轴线，然后用数值方法求解场分布，但是其变换后的二阶偏微分方程存在错误。文中经过严格的推导，获得了正确的结果，纠正了文献［１］中的错误。