On Comparison Of Estimates Of Dispersion Using Generalized Pitman Nearness Criterion

In this paper, estimates QP dispersion matrix and its functions are compared based on generalized Pitman nearness criterion, Various Iosa functions are considered for the purpose. Locally superior estimates are defined and obtained. Comparison of these estimates are made with other standard ones. It is snown that within certain classes, defined in the paper, these are the best estimatcrs ia the generalized Fitman nearness sense     

Recent and classical goodness-of-fit tests for the Poisson distribution

We give a critical synopsis of classical and recent tests for Poissonity, our emphasis being on procedures which are consistent against general alternatives. Two classes of weighted Cramér–von Mises type test statistics, based on the empirical probability generating function process, are studied in more detail. Both of them generalize already known test statistics by introducing a weighting parameter, thus providing more flexibility with regard to power against specific alternatives. In both cases, we prove convergence in distribution of the statistics under the null hypothesis in the setting of a triangular array of rowwise independent and identically distributed random variables as well as consistency of the corresponding test against general alternatives. Therefore, a sound theoretical basis is provided for the parametric bootstrap procedure, which is applied to obtain critical values in a large-scale simulation study. Each of the tests considered in this study, when implemented via the parametric bootstrap method, maintains a nominal level of significance very closely, even for small sample sizes. The procedures are applied to four well-known data sets.     

薄环形相对论电子注介质切伦可夫脉塞

轴向电子注通过介质慢波系统，当波的相速略低于电子注的速度时就可产生相干的切伦可夫辐射，这一现象是一切行波管的基础。本文利用线性理论，通过自洽求解粒子连续性方程和相对论运动方程与麦克斯韦方程组，分析了薄环形相对论电子注介质切伦可夫脉塞的注波互作用，得到了完全描述其薄环形电子注作用的跳变条件，导出了描述其不稳定性的色散方程和注波互作用的同步条件，并求得了波增长率。     

一种适用于空心电子束的慢波系统的理论

提出了一种新型同轴慢波系统——紧密缠绕螺旋线介质棒加载盘荷波导,解析推导了其色散方程和耦合阻抗的表达式,并给出了数值计算结果。结果表明:新型导波结构作为行波管的慢波系统,不但可使行波管具有相对较宽的频带,又可使其具有较高的耦合阻抗。     

Catanova for Two-Way Contingency Tables with Ordinal Variables Using Orthogonal Polynomials

ABSTRACT

The analysis of variance of cross-classified (categorical) data (CATANOVA) is a technique designed to identify the variation between treatments of interest to the researcher. There are well-established links between CATANOVA and the Goodman and Kruskal tau statistic as well as the Light and Margolin R ² for the purposes of the graphical identification of this variation.

The aim of this article is to present a partition of the numerator of the tau statistic, or equivalently, the BSS measure in the CATANOVA framework, into location, dispersion, and higher order components. Even if a CATANOVA identifies an overall lack of variation, by considering this partition and calculations derived from them, it is possible to identify hidden, but statistically significant, sources of variation.     

Identifying Dispersion Effects in Robust Design Experiments—Issues and Improvements

The two experimental methods most commonly used for reducing the effect of noise factors on a response of interest Y aim either to estimate a model of the variability (V(Y), or an associated function), that is transmitted by the noise factors, or to estimate a model of the ratio between the response (Y) and all the control and noise factors involved therein. Both methods aim to determine which control factor conditions minimise the noise factors' effect on the response of interest, and a series of analytical guidelines are established to reach this end. Product array designs allow robustness problems to be solved in both ways, but require a large number of experiments. Thus, practitioners tend to choose more economical designs that only allow them to model the surface response for Y. The general assumption is that both methods would lead to similar conclusions. In this article we present a case that utilises a design based on a product design and for which the conclusions yielded by the two analytical methods are quite different. This example casts doubt on the guidelines that experimental practice follows when using either of the two methods. Based on this example, we show the causes behind these discrepancies and we propose a number of guidelines to help researchers in the design and interpretation of robustness problems when using either of the two methods.     

关于分布函数的散布函数

研究了一种散布函数Ｄｘ（ｔ）的性质，得到了如下结论：设Ｘ～Ｎ（μ１，σ１２），Ｙ～Ｎ（μ２，σ２２），则Ｙ≤ＤＸσ２≤σ     

色散特性对毫米波频率步进雷达影响的研究

对影响毫米波频率步进雷达分辨率的主要因素进行了分析。除目标速度以外,为毫米波频率步进雷达提供频率信号的频率源的色散特性也会对雷达分辨率造成恶化影响。微波频段上的色散特性会被搬移到毫米波频段,导致毫米波发射信号和本振信号的初始相位差不为常数,对雷达系统尤其是距离分辨率造成严重影响。仿真结果与实验结果一致。为了抵消色散特性对雷达分辨率的恶化影响,可以通过对色散特性的补偿来实现。色散特性补偿的方法被应用到实现W波段频率步进频率源的设计中,满足了0.45m距离分辨率的要求。     

Macroeconomic asymmetry in the Eurozone before and after the Global Financial Crisis: An appraisal of the role of the ECB

The launch of the euro in 1999 was assumed to enhance macroeconomic convergence among EMU economies. We test this hypothesis from a comparative perspective, by calculating different indices to measure the degree of macroeconomic dispersion within the Eurozone, the UK and the USA (1999–2019). We use common factor models to produce a single index for each monetary area out of different measures of dispersion. These indices can be used to inform on the degree of optimality of a monetary area. Our results show that macroeconomic dispersion in the Eurozone increased notably even before 2007 and it took significantly longer to return to pre-crisis levels, as compared to the UK and the USA. The paper shows the critical role played by the ECB’s asset purchases programmes in reducing macroeconomic divergences among EMU member states since 2015.     

Rank-based analysis of repeated measures block designs

A rank-based inference is developed for repeated measures balanced incomplete block and randomized complete block designs using a suitable dispersion function. Asymptotic distributions of rank estimators are developed after establishing approximate linearity of the gradient vector of the dispersion function. Unlike available nonparametric procedures for those designs, estimation and testing are tied together. Three different test statistics are developed for testing the linear hypotheses. Friedman's (1937) statistic and Durbin's (1951) statistic are particular cases of one of the three proposed statistics. An estimate of a scale parameter which appears in the ARE expression as well as as in the variences and covariances of the rank estimators is discussed.