A note regarding meta‐analysis of sequential trials with stopping for efficacy

It is shown that fixed‐effect meta‐analyses of naïve treatment estimates from sequentially run trials with the possibility of stopping for efficacy based on a single interim look are unbiassed (or at the very least consistent, depending on the point of view) provided that the trials are weighted by information provided. A simple proof of this is given. An argument is given suggesting that this also applies in the case of multiple looks. The implications for this are discussed. Copyright © 2014 John Wiley & Sons, Ltd.     

当代中国合肥的中等收入者分析(中)

这篇研究报告,以实证材料为基础,以职业为基础,从经济资源、社会声望或组织资源、文化资源的三要素,加上自我认同等因素做了探讨,界定了合肥市中等收入者的年收入为8000-50000元人民币,确定了其规模,分析了合肥市老的中等收入者逐渐演化和新的中等收入者兴起的历史变迁过程及其特点。同时,通过高收入者和低收入者的对比分析,指出中等收入者的社会地位及其在构筑现代化社会阶层结构中的作用,并就如何扩大中等收入者提出了一些政策设想。     

当代中国合肥的中等收入者分析(下)

这篇研究报告 ,以实证材料为基础 ,以职业为基础 ,从经济资源、社会声望或组织资源、文化资源的三要素 ,加上自我认同等因素做了探讨 ,界定了合肥市中等收入者的年收入为 80 0 0～ 5 0 0 0 0元人民币 ,确定了其规模 ,分析了合肥市老的中等收入者逐渐演化和新的中等收入者兴起的历史变迁过程及其特点。同时 ,通过高收入者和低收入者的对比分析 ,指出中等收入者的社会地位及其在构筑现代化社会阶层结构中的作用 ,并就如何扩大中等收入者提出了一些政策设想     

砂浆泵节能调速控制研究

为了解决砂浆泵的流量控制问题，建立了砂浆泵流量控制系统的数学模型，并对控制系统的静态性能和动态性能进行了分析。将BP神经网络的智能控制算法用于砂浆泵的流量控制系统中。为了得到最佳的数学模型，运用了极点配置的优化方法，并且运用Matlab／Simulink软件对流量控制系统的性能进行了仿真。最后经过实验证明该控制方法使砂浆泵流量控制系统的控制性能得到很大的提高，表明该控制方法是可行的，可以对砂浆泵的流量起到精确的控制作用，满足生产过程的要求。     

The pseudo‐GEE approach to the analysis of longitudinal surveys

Longitudinal surveys have emerged in recent years as an important data collection tool for population studies where the primary interest is to examine population changes over time at the individual level. Longitudinal data are often analyzed through the generalized estimating equations (GEE) approach. The vast majority of existing literature on the GEE method; however, is developed under non‐survey settings and are inappropriate for data collected through complex sampling designs. In this paper the authors develop a pseudo‐GEE approach for the analysis of survey data. They show that survey weights must and can be appropriately accounted in the GEE method under a joint randomization framework. The consistency of the resulting pseudo‐GEE estimators is established under the proposed framework. Linearization variance estimators are developed for the pseudo‐GEE estimators when the finite population sampling fractions are small or negligible, a scenario often held for large‐scale surveys. Finite sample performances of the proposed estimators are investigated through an extensive simulation study using data from the National Longitudinal Survey of Children and Youth. The results show that the pseudo‐GEE estimators and the linearization variance estimators perform well under several sampling designs and for both continuous and binary responses. The Canadian Journal of Statistics 38: 540–554; 2010 © 2010 Statistical Society of Canada     

A note on the use of the shapiro- wilk test of exponentiality for complete samples

The consistency of the Shapiro-Wilk test of exponentialIty is examined. In testing repair-time data for exponentiality, the natural class of lognormal alternatives is shown to contain a subclass over which the test Is Inconsistent. A transformation of the data is recommended to alleviate the problem.     

A maximum likelihood prediction function for the linear model with consistency results

An alternative technique to current methods for constructing a prediction function for the normal linear regression model is proposed based on the concept of maximum likelihood. The form of this prediction function is evaluated and normalized to produce a multivariate Student's t-density. Consistency properties are established under regularity conditions, and an empirical comparison, based on the Kullback-Leibler information divergence, is made with some other prediction functions.     

Approximation and information topologies

In this paper approximation properties of finite dimensional parametric models are described in terms of an information metric: the Hellinger distance. Under conditions on the parametric family given solely in terms of a comparison of the Hellinger distance with the parameter metric, optimal rates of convergence are described. It is also shown how to use these conditions on the parametric family to determine whether consistent estimation is possible. We give applications of the theorems to regular and non-regular parametric families, and to nonlinear regression.     

Conditional inference in linear versus nonlinear models for binary time series

The modelling of discrete such as binary time series, unlike the continuous time series, is not easy. This is due to the fact that there is no unique way to model the correlation structure of the repeated binary data. Some models may also provide a complicated correlation structure with narrow ranges for the correlations. In this paper, we consider a nonlinear dynamic binary time series model that provides a correlation structure which is easy to interpret and the correlations under this model satisfy the full?1 to 1 range. For the estimation of the parameters of this nonlinear model, we use a conditional generalized quasilikelihood (CGQL) approach which provides the same estimates as those of the well-known maximum likelihood approach. Furthermore, we consider a competitive linear dynamic binary time series model and examine the performance of the CGQL approach through a simulation study in estimating the parameters of this linear model. The model mis-specification effects on estimation as well as forecasting are also examined through simulations.     

电潜泵–气举组合接力举升工艺研究

针对单项人工举升工艺不能满足的深抽问题，从举升工艺原理与工艺管柱结构角度，提出了多种可能的组合举升方案以及组合原则。鉴于气举的独特优点，深井泵与气举的组合，尤其是电潜泵（ESP）与气举（GL）的组合具有出优点，适合大排量深抽。对 ESP–GL 的举升管柱结构型式进行了探讨，提出了利用小直径油管与气举阀直接连接代替常规环空气举的实施方案，避免了环空直接气举对动液面深度和下部深井泵的影响，为其他举升工艺与气举的组合创造了条件。利用提出的 ESP–GL 组合设计方法所开展的设计计算表明，在电潜泵排量和举升压头不变的条件下，气举组合接力举升后可使电泵的下泵深度达到 6 000 m 以上，为深层油气藏的大排量举升提供了技术手段；而在 ESP 下泵深度不变的条件下，气举组合后有助于提高其产量。