Constrained inference for generalized linear models with incomplete covariate data

Missing data are common in many experiments, including surveys, clinical trials, epidemiological studies, and environmental studies. Unconstrained likelihood inferences for generalized linear models (GLMs) with nonignorable missing covariates have been studied extensively in the literature. However, parameter orderings or constraints may occur naturally in practice, and thus the efficiency of a statistical method may be improved by incorporating parameter constraints into the likelihood function. In this paper, we consider constrained inference for analysing GLMs with nonignorable missing covariates under linear inequality constraints on the model parameters. Specifically, constrained maximum likelihood (ML) estimation is based on the gradient projection expectation maximization approach. Further, we investigate the asymptotic null distribution of the constrained likelihood ratio test (LRT). Simulations study the empirical properties of the constrained ML estimators and LRTs, which demonstrate improved precision of these constrained techniques. An application to contaminant levels in an environmental study is also presented.     

Constructing optimal projection designs

ABSTRACT

The early stages of many real-life experiments involve a large number of factors among which only a few factors are active. Unfortunately, the optimal full-dimensional designs of those early stages may have bad low-dimensional projections and the experimenters do not know which factors turn out to be important before conducting the experiment. Therefore, designs with good projections are desirable for factor screening. In this regard, significant questions are arising such as whether the optimal full-dimensional designs have good projections onto low dimensions? How experimenters can measure the goodness of a full-dimensional design by focusing on all of its projections?, and are there linkages between the optimality of a full-dimensional design and the optimality of its projections? Through theoretical justifications, this paper tries to provide answers to these interesting questions by investigating the construction of optimal (average) projection designs for screening either nominal or quantitative factors. The main results show that: based on the aberration and orthogonality criteria the full-dimensional design is optimal if and only if it is optimal projection design; the full-dimensional design is optimal via the aberration and orthogonality if and only if it is uniform projection design; there is no guarantee that a uniform full-dimensional design is optimal projection design via any criterion; the projection design is optimal via the aberration, orthogonality and uniformity criteria if it is optimal via any criterion of them; and the saturated orthogonal designs have the same average projection performance.     

基于CFD的离心泵结构参数优化

为获得离心泵的最佳结构参数，根据给定的离心泵设计参数确定离心泵的结构形式和性能评价指标，计算离心泵各结构参数，利用CFD对离心泵进行流场数值模拟分析，设计了叶轮结构L16（45）正交实验表，选择叶轮进口安装角βb1、出口安装角βb2、包角φ、进口直径D1、出口直径D2为正交实验的5个因素，完成了正交实验并对实验结果进行极差分析，得到各结构参数对各优化方向评价指标影响排序及其影响情况，构造出效率最大、汽蚀余量最小条件下的目标函数及统一目标函数，并运用遗传算法对离心泵效率和汽蚀进行多目标优化，得到离心泵的最佳结构组合参数.     

The Reform of Mutual Aid Associations in Japan: Civil Service Employee Pension Reform in 2012

Civil service employee pension reform began by removing non‐clerical work from the main body of the Mutual Aid Association (MAA) pension system. Further changes were based on administrative reform and pension jealousy. In particular, the Nakasone cabinet's administrative reform privatized the non‐clerical sector. Before the 1979 reform, the pensionable age was 55 for the MAA and 60 for the Employee Pension Insurance (EPI) scheme. The MAA pension benefit formula adopted the final salary system, which was larger than the average lifetime salary calculation used for EPI benefits. The final salary system was abolished during the 1986 reform. Public employee criticism over “Amakudari” led to further civil service employee remuneration reform in 2005. In 2007, the Social Insurance Agency pension record scandal led to a change of government by 2009. The biggest reform of the MAA pension system was the abolishment of the occupational portion of the pension, a compromise between the government and unions. We project that this compromise will cost 22 trillion yen over 90 years old. After 2055, the newly established MAA pension scheme will be abolished; thus the public pension may finally be sustainable.     

The future of work: Meeting the global challenges of demographic change and automation

This article explores future job creation needs under conditions of demographic, economic and technological change. The authors first estimate the implications for job creation during 2020–30 of population growth, changes in labour force participation and the achievement of target unemployment rates, by age and sex. Second, they analyse the job creation needs by country income group and, lastly, examine the effects of accelerated automation. Projections indicate that shifting demographics will account for a far greater share of the estimated global need for 340 million jobs over 2020–30 than automation.     

Efficiency-consistency in designs

It is shown that if an interaction is estimated orthogonally to all other interactions in an equireplicate connected n-factor design, then the design is efficiency-consistent for this interaction.     

Divergences and duality for estimation and test under moment condition models

We introduce estimation and test procedures through divergence minimization for models satisfying linear constraints with unknown parameter. These procedures extend the empirical likelihood (EL) method and share common features with generalized empirical likelihood approach. We treat the problems of existence and characterization of the divergence projections of probability distributions on sets of signed finite measures. We give a precise characterization of duality, for the proposed class of estimates and test statistics, which is used to derive their limiting distributions (including the EL estimate and the EL ratio statistic) both under the null hypotheses and under alternatives or misspecification. An approximation to the power function is deduced as well as the sample size which ensures a desired power for a given alternative.     

长链烷基疏水改性双醛淀粉的制备优化研究

以双醛淀粉、十八烷基伯胺为原料，在二甲基亚砜溶液中制得疏水改性双醛淀粉.考察投料比（醛基与氨基的摩尔比）、反应温度、反应时间和催化剂用量对改性双醛淀粉得率的影响，并采用正交实验优化实验参数.利用接触角测定仪对样品进行静态水接触角实验.结果表明，当投料比（醛基与氨基的摩尔比）为1∶0.9、反应温度40 ℃、反应时间8 h、催化剂用量为3 ﹪时，改性双醛淀粉得率最高，达44.21 ﹪.疏水性能测试可以看出，长链烷基的引入能有效提高双醛淀粉的疏水性能.     

Multivariate analysis of variance for functional data

Functional data are being observed frequently in many scientific fields, and therefore most of the standard statistical methods are being adapted for functional data. The multivariate analysis of variance problem for functional data is considered. It seems to be of practical interest similarly as the one-way analysis of variance for such data. For the MANOVA problem for multivariate functional data, we propose permutation tests based on a basis function representation and tests based on random projections. Their performance is examined in comprehensive simulation studies, which provide an idea of the size control and power of the tests and identify differences between them. The simulation experiments are based on artificial data and real labeled multivariate time series data found in the literature. The results suggest that the studied testing procedures can detect small differences between vectors of curves even with small sample sizes. Illustrative real data examples of the use of the proposed testing procedures in practice are also presented.     

正交试验设计优化加涅九步教学方案的应用研究

加涅九步教学法在我国高等教育教学中已经得到了广泛的推广和应用。然而,每一步所采用的时间和具体教学技术都因课程而异,不能简单复制。为了使教师能在更短的时间内准确找出适合自己所授课程的教学方案,并科学灵活地使用加涅九步教学法,该研究介绍了一种加涅九步教学方案正交试验评估法。通过在课程“制药化工原理”和“食品物性学”的应用,效果显著,对于食品专业的本科生教学具有一定的参考意义。