Regression analysis of longitudinal data with outcome‐dependent sampling and informative censoring

We consider a regression analysis of longitudinal data in the presence of outcome‐dependent observation times and informative censoring. Existing approaches commonly require a correct specification of the joint distribution of longitudinal measurements, the observation time process, and informative censoring time under the joint modeling framework and can be computationally cumbersome due to the complex form of the likelihood function. In view of these issues, we propose a semiparametric joint regression model and construct a composite likelihood function based on a conditional order statistics argument. As a major feature of our proposed methods, the aforementioned joint distribution is not required to be specified, and the random effect in the proposed joint model is treated as a nuisance parameter. Consequently, the derived composite likelihood bypasses the need to integrate over the random effect and offers the advantage of easy computation. We show that the resulting estimators are consistent and asymptotically normal. We use simulation studies to evaluate the finite‐sample performance of the proposed method and apply it to a study of weight loss data that motivated our investigation.     

Projection designs for mixture experiments in orthogonal blocks

Mixture experiments are often carried out in the presence of process variables, such as days of the week or different machines in a manufacturing process, or different ovens in bread and cake making. In such experiments it is particularly useful to be able to arrange the design in orthogonal blocks, so that the model in tue mixture vanauies may ue iitteu inucpenuentiy or tne UIOCK enects mtrouuceu to take account of the changes in the process variables. It is possible in some situations that some of the ingredients in the mixture, such as additives or flavourings, are present in soian quantities, pernaps as iuw a.s 5% ur even !%, resulting in the design space being restricted to only part of the mixture simplex. Hau and Box (1990) discussed the construction of experimental designs for situations where constraints are placed on the design variables. They considered projecting standard response surface designs, including factorial designs and central composite designs, into the restricted design space, and showed that the desirable property of block orthogonality is preserved by the projections considered. Here we present a number of examples of projection designs and illustrate their use when some of the ingredients are restricted to small values, such that the design space is restricted to a sub-region within the usual simplex in the mixture variables.     

三维平衡多水平轮换设计及其连续性估计方法研究

 针对现行多水平轮换调查存在的一系列问题，本文提出三维平衡多水平轮换模式设计及其广义组合估计方法。在这套设计方法中，将各种偏差和两类相关关系引入到广义组合估计量公式中，提高了估计量的准确性，同时在多目标调查下还应用最优化方法确定一套最优系数，使得连续性的多目标调查的整体估计精度达到最高，同时又兼顾各类目标量的精度要求。这套系统化、理论化的设计方法将为我国未来开展多水平轮换调查提供理论指导。     

一般截面复合曲梁在复杂受力下的正应力研究

给出了一般截面形状的复合曲梁在复杂载荷作用下正应力的计算公式，作为特殊情况，该梁在平面弯曲时的相应公式也可以从上述公式得到。最后给出了计算实例。     

Globalisation Continues: The Maastricht Globalisation Index Revisited and Updated

Globalisation is a complex process which leads to an increasing connectedness and interrelatedness in the political, economic, social and cultural, technological, and environmental domain on many different scales. While this is a truly global phenomenon, it also has different impacts and manifestations in different geographic localities. As a result, different nations exhibit different levels of globalisation or connectedness. Further, perspectives on globalisation are manifold and change over time, therefore it is crucial to continuously reflect upon and revise existing methodologies. Composite indices are a powerful tool to capture and measure complex concepts that allow for monitoring complex systems over time and yield relative rankings and comparisons. This article presents a revised and updated Maastricht Globalisation Index for 117 countries and three points in time—2000, 2008, and 2012—including a new calculation methodology and data. Results show that globalisation still continues but has slowed down, due to the recent economic crisis.     

利用主成分分析法对流动性统一度量的研究

在介绍流动性维度和常用的流动性指标的基础上,利用2002年和2003年上证的高频数据,以半年为一个时段,计算各股的常用5分钟流动性指标。通过相关性分析和主成分分析法对各支股票的常用流动性指标进行考察,获得了一个能够对流动性各个维度都有一定反映的综合流动性指标。研究结果发现绝大数股票都可以用主成分分析法得到的4个新的变量来进行描述,且这4个变量具有实际的经济学意义。     

基于回归组合技术的连续性抽样估计方法研究

在使用样本轮换的连续性抽样调查中,不仅可以利用前期调查的研究变量的信息,还可使用现期调查的辅助变量信息来建立回归模型进行回归估计,进而构造回归组合估计量,并在此基础上确定最优样本轮换率和最优权重系数,使得回归组合估计量的方差最小,从而更大程度地提高连续性抽样调查的估计精度。     

复合地基在桥台深软土地基处理中的应用及施工

介绍水泥土搅拌桩复合地基在公路桥桥台深软土地基中的应用实践,以实际工程案例介绍软土地基强化的计算.通过对桥台下深软土地基的加强处理,防止了公路桥梁在桥身与桥台结合部位由于桥台沉降过大而引起的过大跌落.     

基于功能梯度磁电复合材料的新型自偏置磁传感器

文章采用超磁致伸缩材料Terfenol-D(Tb0.37Dy0.63Fe2)、金属玻璃Metglas 2605SA1和压电材料PZT(Pb(Zr, Ti)O3)，设计了一种基于功能梯度磁电复合材料的新型自偏置磁传感器.利用Metglas和Terfenol-D之间的磁导率和矫顽力差异产生较强的磁化梯度，打破原有的平衡状态，导致内建磁场产生，进一步提高了零偏置磁场下磁致伸缩材料的压磁系数和磁电响应.实验结果表明：该传感器获得了较高的低频和高频零偏置磁电电压系数，分别达到9.14 mV/Oe和572 mV/Oe，并且谐振磁电电压输出和激励交变磁场之间呈线性变化关系.该自偏置磁传感器避免了传统磁电传感器对偏置磁场的依赖，具有制作简单、成本低、体积小，无需偏置磁场以及灵敏度高等优点.     

On level and powee of anderson and hauck's peocedure for testing equivalence in compative bioavailability

The paper refers to a new procedure of Anderson and Hauck for the well-known problem of deciding whether two means of normal distributions with common but unknown variance differ within an admissible range. Analytical expressions for level and power of this method are derived and some numerical examples are given. A bound for the difference between real and no¬minal level is obtained which does not involve the variance.