Minimum variance rectangular designs for U-statistics

We consider a certain class of rectangular designs for incomplete U-statistics based on Latin squares and show it to be optimal with respect to the minimal variance criterion. We also show it to be asymptotically efficient when compared with the corresponding complete statistics, as well as uniformly more efficient than the random subset selection. We provide the necessary and sufficient conditions for the existence of our design and give some examples of applications.     

数字城市建设中的技术理性问题研究

数字城市建设是目前国家信息化建设的重点.在建设过程中由于对数字城市建设定位以及战略意义的认识不足,导致技术理性主导数字城市化建设工作的现象突出,带来较大的社会影响.在对技术理性僭越的批判的同时,数字城市建设应当重视人文文化建设,建立人文理念,重视培育市场需求与环境建设,稳步渐进,讲求实效,在应用中求发展,注重社会效益与经济效益.     

Z平面矩阵变换的数字滤波器设计

说明了用矩阵变换的方法在 Z 平面内把已知低通数字滤波器直接变换成所需要的各种数字滤波器的原理和方法.这种方法原理简单、运算速度快,具有一定的实际应用价值.     

一种新的自适应卡尔曼滤波算法——ALR算法

本文提出一种新的自适应卡尔曼滤波算法——ALR(Adaptive Least Residual)算法.该算法从经典的卡尔曼滤波出发,使残差达到最小,以残差(residual)样本值代替统计值,再用最陡下降法估计算自适应权增益,最后得到一组自适应滤波公式.通过理论分析和计算机模拟,证明该算法具有算法简单、运算量小等优点,适于在自适应系统辨识、自适应谱估计中作实时处理.     

具有低运算噪声的DM数字滤波器硬件设备

本文提出了基于DDA器件原理的增量调制递归数字滤波器的实现方案,并做出了实验设备.实验结果表明DDA-DM递归数字滤波器具有低运算噪声的优点,其性能与理论分析十分一致.     

论网络环境下图书馆信息服务模式

信息服务是现代图书馆的主要职能,网络的出现,革新了图书馆传统的信息服务模式,这主要表现在服务手段的现代化、服务方式的虚拟化、服务范围的社会化、服务主体的专家化、服务效果的便捷化等方面.针对网络环境下图书馆服务的新特点,图书馆应充分发挥网络优势,开展多种形式的网络化信息服务,以满足读者不断增长的信息需求.     

Weak approximations for quantile processes of stationary sequences

ABSTRACT By studying the deviations between uniform empirical and quantile processes (the so-called Bahadur-Kiefer representations) of a stationary sequence in properly weighted sup-norm metrics, we find a general approach to obtaining weighted results for uniform quantile processes of stationary sequences. Consequently we are able to obtain weak convergence for weighted uniform quantile processes of stationary mixing and associated sequences. Further, by studying the sup-norm distance of a general quantile process from its corresponding uniform quantile process, we find that information at the two end points of the uniform quantile process can be so utilized that this weighted sup-norm distance converges in probability to zero under the so-called Csörgõ-Révész conditions. This enables us to obtain weak convergence for weighted general quantile processes of stationary mixing and associated sequences.     

Not the First Digit! Using Benford's Law to Detect Fraudulent Scientif ic Data

Digits in statistical data produced by natural or social processes are often distributed in a manner described by ‘Benford's law’. Recently, a test against this distribution was used to identify fraudulent accounting data. This test is based on the supposition that first, second, third, and other digits in real data follow the Benford distribution while the digits in fabricated data do not. Is it possible to apply Benford tests to detect fabricated or falsified scientific data as well as fraudulent financial data? We approached this question in two ways. First, we examined the use of the Benford distribution as a standard by checking the frequencies of the nine possible first and ten possible second digits in published statistical estimates. Second, we conducted experiments in which subjects were asked to fabricate statistical estimates (regression coefficients). The digits in these experimental data were scrutinized for possible deviations from the Benford distribution. There were two main findings. First, both digits of the published regression coefficients were approximately Benford distributed or at least followed a pattern of monotonic decline. Second, the experimental results yielded new insights into the strengths and weaknesses of Benford tests. Surprisingly, first digits of faked data also exhibited a pattern of monotonic decline, while second, third, and fourth digits were distributed less in accordance with Benford's law. At least in the case of regression coefficients, there were indications that checks for digit-preference anomalies should focus less on the first (i.e. leftmost) and more on later digits.     

教务管理的数字化实现

随着科学技术的迅猛发展,计算机的应用也越来越广泛,基于局域网、Internet技术的数字化教务管理也越来越迫在眉睫.教务管理的数字化水平反映了一个学校的教务综合水平,同时也从侧面反映一个学校的教育教学手段的先进与否,更反映一个学校的教务管理是否能与时俱进,使之与科学技术的发展同步.     

语言实验室应向数字化方向发展

从数字化语言学习系统的原理及功能入手,作者通过将数字化语言学习系统与传统型语言学习系统、智能化语言学习系统及计算机多媒体教学网络进行比较分析,总结出它们的差异,提出了语言学习系统的发展趋势.