Probabilistic population projections for countries with generalized HIV/AIDS epidemics

In 2015, the United Nations (UN) issued probabilistic population projections for all countries up to 2100, by simulating future levels of total fertility and life expectancy and combining the results using a standard cohort component projection method. For the 40 countries with generalized HIV/AIDS epidemics, the mortality projections used the Spectrum/Estimation and Projection Package (EPP) model, a complex, multistate model designed for short-term projections of policy-relevant quantities for the epidemic. We propose a simpler approach that is more compatible with existing UN projection methods for other countries. Changes in life expectancy are projected probabilistically using a simple time series regression and then converted to age- and sex-specific mortality rates using model life tables designed for countries with HIV/AIDS epidemics. These are then input to the cohort component method, as for other countries. The method performed well in an out-of-sample cross-validation experiment. It gives similar short-run projections to Spectrum/EPP, while being simpler and avoiding multistate modelling.     

Three-level main-effects designs exploiting prior information about model uncertainty

To explore the projection efficiency of a design, Tsai, et al [2000. Projective three-level main effects designs robust to model uncertainty. Biometrika 87, 467–475] introduced the Q criterion to compare three-level main-effects designs for quantitative factors that allow the consideration of interactions in addition to main effects. In this paper, we extend their method and focus on the case in which experimenters have some prior knowledge, in advance of running the experiment, about the probabilities of effects being non-negligible. A criterion which incorporates experimenters’ prior beliefs about the importance of each effect is introduced to compare orthogonal, or nearly orthogonal, main effects designs with robustness to interactions as a secondary consideration. We show that this criterion, exploiting prior information about model uncertainty, can lead to more appropriate designs reflecting experimenters’ prior beliefs.     

文学视野下的古栈道文化遗存

连云栈道是古代通行汉中和巴蜀的重要栈道之一,素以恢宏险峻而名驰天下。作为古代的交通要津,它承载着极为厚重的历史文化信息,记录着王朝兴废的更迭嬗变,演绎出一幕幕惊心动魄、可歌可泣的历史活剧,雄杰之士为之折腰,骚人墨客赋咏不绝。或直笔正描,赞叹栈道的奇伟险绝;或托物兴感,展示坎坷不遇的失意情怀;或触景生情,抒发古今变异、世事沧桑、兴亡倏忽的人生感触;或侧写旁点,表现伤时念乱的时代忧患意识,显示出多元的艺术视野。     

大都市服务经济发展的劳动力因素——基于从业人口数据模型的分析

本文在对比分析纽约、东京两个国外大都市服务经济发展的一般规律和劳动力变动特征基础上，以服务业从业人口结构和规模的历史数据作为切入点，对比分析上海服务业的发展状况，指出上海与纽约、东京服务经济发展的差距及存在的主要问题。并进一步构建了基于从业人口数据回归分析的服务经济发展预测模型，运用该模型对上海市未来服务经济从业人口的比重进行预测．分析表明上海的服务业发展正处于加速增长期，并仍将保持快速发展的势头，按此速度到2020年其从业人数比重可达80％；要实现上海服务经济的健康、快速发展应采取积极的人才引进战略和人口政策。     

Invariant co-ordinate selection

Summary.  A general method for exploring multivariate data by comparing different estimates of multivariate scatter is presented. The method is based on the eigenvalue–eigenvector decomposition of one scatter matrix relative to another. In particular, it is shown that the eigenvectors can be used to generate an affine invariant co-ordinate system for the multivariate data. Consequently, we view this method as a method for invariant co-ordinate selection . By plotting the data with respect to this new invariant co-ordinate system, various data structures can be revealed. For example, under certain independent components models, it is shown that the invariant co- ordinates correspond to the independent components. Another example pertains to mixtures of elliptical distributions. In this case, it is shown that a subset of the invariant co-ordinates corresponds to Fisher's linear discriminant subspace, even though the class identifications of the data points are unknown. Some illustrative examples are given.     

On the stability of the risk hull method for projection estimators

We consider in this paper the regularization by projection of a linear inverse problem Y=Af+εξ$Y=\mathit{Af}+\epsilon \xi$ where ξ$\xi$ denotes a Gaussian white noise, A   a compact operator and ε>0$\epsilon >0$ a noise level. Compared to the standard unbiased risk estimation (URE) method, the risk hull minimization (RHM) procedure presents a very interesting numerical behavior. However, the regularization in the singular value decomposition setting requires the knowledge of the eigenvalues of A$A$. Here, we deal with noisy eigenvalues: only observations on this sequence are available. We study the efficiency of the RHM method in this situation. More generally, we shed light on some properties usually related to the regularization with a noisy operator.     

长株潭城市群水资源承载力的实证研究

在界定水资源承载力概念的基础上,构建了长株潭城市群水资源承载能力的指标体系,采用基于遗传算法的投影寻踪聚类模型对长株潭城市群水资源承载能力进行了实证分析,提出了提高长株潭城市群水资源承载能力水平的几点应对措施。     

社会保障基金长期财务随机预测模型的比较与选择

为了测算分析社会保障制度的可持续发展,世界上不少国家建立了社会保障基金长期财务预测模型。与确定性财务预测模型相比,随机预测模型有利于阐明预测结果所面临的不确定。美国在运用随机预测模型对社会保障基金的财务状况做出预测方面走在世界最前端,我国对社会保障基金随机预测模型的研究基本处于空白。本文对美国社会保障署和国会预算办公室采用的社会保障基金长期随机预测模型进行了比较分析,对两种模型的选择给出了建议,最后提出了我国建立社会保障基金长期预测模型的一些建议。     

Uniformity pattern and related criteria for q-level factorials

The objective of this paper is to study the issue of the projection discrepancy along the line of Liu (2002) and Fang and Qin (2005) based on discrete discrepancy measure proposed in Qin and Fang (2004), which has wide application to the field of fractional factorials. Here we also study the projection properties for q-level factorials and provide connection between minimum projection uniformity and other optimality criteria. A lower bound to projection discrepancy for q-level factorials is presented here.