the Block–Block Bootstrap: Improved Asymptotic Refinements

The asymptotic refinements attributable to the block bootstrap for time series are not as large as those of the nonparametric iid bootstrap or the parametric bootstrap. One reason is that the independence between the blocks in the block bootstrap sample does not mimic the dependence structure of the original sample. This is the join‐point problem. In this paper, we propose a method of solving this problem. The idea is not to alter the block bootstrap. Instead, we alter the original sample statistics to which the block bootstrap is applied. We introduce block statistics that possess join‐point features that are similar to those of the block bootstrap versions of these statistics. We refer to the application of the block bootstrap to block statistics as the block–block bootstrap. The asymptotic refinements of the block–block bootstrap are shown to be greater than those obtained with the block bootstrap and close to those obtained with the nonparametric iid bootstrap and parametric bootstrap.     

English Language Teaching——Teaching Listening

Modern language teaching theory highly emphasizes the effect of"listening"on the learning and the use of language.The teaching of English listening isn’t only a teaching of language,also a training of ability.It isn’t only the main way of acquiring language information,but the base of improving other skills.Many Chinese students regard the listening test as the most difficult part of a whole test.So during the English teaching,it is vital important for teachers to master the skill of designing the listening activities.     

A REVIEW OF BOUNDS FOR THE EFFICIENCY FACTOR OF BLOCK DESIGNS

This paper draws together bounds for the efficiency factor of block designs, starting with the papers of Conniffe & Stone (1974) and Williams & Patterson (1977). By extending the methods of Jarrett (1983), firstly to cover supercomplete block designs and then to cover resolvable designs, a set of bounds is obtained which provides the best current bounds for any block design with equal replication and equal block size, including resolvable designs and two-replicate resolvable designs as special cases. The bounds given for non-resolvable designs apply strictly only to designs which are either regular-graph (John & Mitchell, 1977) or whose duals are regular-graph. It is conjectured (John & Williams, 1982) that they are in fact global bounds. Similar qualifications apply to the bounds for resolvable designs.     

Automated statistical methods for measuring the strength of block ciphers

A block cipher is one of the most common forms of algorithms used for data encryption. This paper describes an efficient set of statistical methods for analysing the security of these algorithms under the black-box approach. The procedures can be fully automated, which provides the designer or user of a block cipher with a useful set of tools for security analysis.     

Optimal balanced block designs for correlated observations

The construction of universally optimal designs, if such exist, is difficult to obtain, especially when there are some nuisance effects or correlated errors. The hub correlation is a special correlation structure with applications to experiments in genetics, networks and other areas in industry and agriculture. There may be restrictions on the correlation values of the hub structure depending on the experiment. Optimality of block designs under hub correlation has been studied for the case of a constant correlation value. In this article, we consider the hub structure when one of the correlation values is different from the others, and the universally optimal block designs, binary or non-binary, are theoretically obtained. Also, we introduce an algorithm to construct the optimal designs. The Canadian Journal of Statistics 48: 596–604; 2020 © 2020 Statistical Society of Canada     

成人卫生统计学教学改革初探

随着广大卫生技术人员对掌握卫生统计学知识的需求越来越大,针对成人教育的特点,本 文提出模块教学的概念,进行卫生统计学教学内容、方法、教学手段的改革。     

自适应变方块图像编码

介绍了一种适用于静止图像传输的自适应变方块图像编码方法。它以8×8像素的方块为基础,以解码后的归一化均方误差大小为依据,进行多次分割传送及逐级解码显示。各次传输的图像数据由每次分割后其相应均值差而定,收端以方块均值来恢复图像。计算机模拟实验表明:在恢复图像的主观质量与原始图像相比,看不出明显差别时,其平均编码率为0.6bit/pel 左右。     

On the asymptotic distribution of a class of aligned rank order test statistics in randomized block designs

In the present investigation, the unconditional asymptotic distribution of a class of aligned rank order test statistics for randomized block designs is derived under the null hypothesis and for nearby alternatives, as the number of blocks tends to infinity. The proofs of these results are based on the asymptotic equivalence in quadratic mean between aligned observations and their ranks and thus are quite similar to the Hájek and SKidák (1967) approach.     

突然起动无限长平板的流场动量输运分析

以修正的牛顿内摩擦定律的为基础,建立了瞬态动量方程,用拉普拉斯变换法对无限长平板突然起动的动态流场进行了求解,求得瞬态过程的动量、动量流分布函数。结果表明了速度、动量流输运的波动机制。