Neural networks and flexible regression and discrimination

Feed-forward neural networks—also known as multi-layer perceptrons—are now widely used for regression and classification. In parallel but slightly earlier, a family of methods for flexible regression and discrimination were developed in multivariate statistics, and tree-induction methods have been developed in both machine learning and statistics. We expound and compare these approaches in the context of a number of examples.     

社会经济不平等及其测度

对社会中普遍存在的不平等现象 ,人们很早就给予了关注和研究 ,并提出了可行的测度不平等程度的方法和指标。然而我们注意到 ,这些传统的研究成果所体现的不平等 ,主要集中在社会的“收入不平等”上 ,实质上也就是经济不平等的即时反映。但生活毕竟不只是生存问题 ,社会中的不平等远不仅是人们收入多少的差异 ,还有很多无法用货币或数值来表现的不平等 ,而这些往往是人们生活质量更深层次、更真实的反映。“社会经济不平等”概念的提出 ,跳出了“收入不平等”这个狭隘的思维体系 ,也为全面研究社会中诸多不平等现象奠定了新的基石。虽然这一…     

Neural networks and flexible regression and discrimination

Feed-forward neural networks—also known as multi-layer perceptrons—are now widely used for regression and classification. In parallel but slightly earlier, a family of methods for flexible regression and discrimination were developed in multivariate statistics, and tree-induction methods have been developed in both machine learning and statistics. We expound and compare these approaches in the context of a number of examples.     

Trimmed and Outer Means and Their Variances

Some properties of trimmed and outer means for the normal situation are considered; in particular, the mean of the outer half of the sample has the same variance as the mean of the inner half. An inequality involving variances of unbiased estimators of location and their complements is derived and some of its consequences are examined.     

Distance Mean and Variance Functions and Sphere Fitting

Motivated by circle fitting to spatial distributions, this paper looks at the relationship between the expected distance function and the radial density. Inversion of this relationship is given simply in dimensions 1 and 3 and generally by using Mellin transforms. Examples of variance function behaviour are given and calculations of the coefficient of sphericity shown.     

平衡城乡收入分配 协调工农业生产发展

文章以农业、农村和农民为重点,依据丰富翔实的资料,深入论述了我国目前城乡居民收入分配差距趋向扩大的成因,指出了宏观调控收入分配差距的具体措施,以促进工农业调协发展.     

关于民间借贷与高利贷的思考

文章在分析民间借贷与高利贷现象的基础上 ,着重分析了高利贷的死灰复燃与蔓延、高利贷的主要形式和造成的严重危害 ,并对产生高利贷行为的因素进行了分析 ,提出了对加强民间借贷工作的对策建议。     

世贸组织及其宗旨、目标和职能

世界贸易组织（Ｗｏｒｌｄ Ｔｒａｄｅ Ｏｒｇａｎｉｚａｔｉｏｎｏ．缩写ＷＴＯ，简称“世贸组织”）成立了１９９５年１月１日，是独立于联合国的永久性国际组织，其前身是成立于１９４８年的关税和贸易总协定，根据《建立世界贸易组织协定》的规定， １９９５年１月１日世贸组织正式成立，１９９５年与关贸总协定共存一年后，担当起全球经济贸易组织的角色，发挥其积极作用。 世贸组织 日前拥有 １３５个成员，与国际货币基金组织、世界银行并称为世界经济的“三大支柱”。世贸组织涵盖货物贸易、服务贸易以及知识产权贸易。其基本原则和…     

Empirical and rank processes of observations and residuals

Empirical and rank processes of a sample are shown to converge under weak conditions. These results are then extended to analogous empirical and rank processes formed from the residuals of a linear model. Representations of the limiting processes are obtained by means of a special construction. The technicalities are honed to require few regularity conditions.     

Extension and necessity of Cheng and Wu conditions

Repeated Measurement Designs, with two treatments, n (experimental) units and p periods are examined. The model examined is with uncorrelated observations following a continuous distribution with constant variance and the parameters of interest are (i) the difference of direct effects and (ii) the difference of residual effects. In this paper (a) the difference of Universal optimality and Φ-optimality is clarified and (b) the sufficient conditions of Cheng and Wu (1980) are extended to include the case n=2 mod 4, p even, (c) also it is shown that these conditions are also necessary for Φ-optimality for estimating direct as well as residual effects, and (d) a method is proposed to construct Φ-optimal designs and examples are given when n even and p=3, n=0 mod 4 and p=4, n=2 mod 4 and p=4. In the last case the estimated parameters in the optimal design are correlated.     

留守与流动儿童登记与调查体系的设计与实施

 本文通过对留守与流动儿童定义分歧的梳理及要素特征分析,明确“留守”与“流动”儿童的概念、内涵与外延;设计以“户籍资料”为基础,分别构建以“教育部门”、“公安部门”为主的留守、流动儿童登记体系,建立关于留守与流动儿童登记的长效机制。针对留守与流动儿童这两类特殊群体,设计研究的调查表,该表由基本信息与综合信息两部分组成,并构建以“登记表信息及户籍信息”为依据,以“统计部门为主”统计调查体系。通过留守与流动儿童登记与调查体系的设计,并加以实施,便于准确地掌握情况、了解问题,为留守与流动儿童的学术研究提供基础的信息资料,为相关部门制定对策提供必要的依据。     

Local and Variable Bandwidths and Local Linear Regression

Two types of non-global bandwidth, which may be called local and variable, have been defined in attempts to improve the performance of kernel density estimators. In nonparametric regression, local linear fitting has become a method of much popularity. It is natural, therefore, to consider the use of non-global bandwidths in the local linear context, and indeed local bandwidths are often used. In this paper, it is observed that a natural proposal in the literature for combining variable bandwidths with local linear fitting fails in the sense that the resulting mean squared error properties are those normally associated with local rather than variable bandwidths. We are able to understand why this happens in terms of weightings that are involved. We also attempt to investigate how the bias reduction expected of well-chosen variable bandwidths might be achieved in conjunction with local linear fitting.     

Frailty models and copulas: similarities and differences

Copulas and frailty models are important tools to model bivariate survival data. Equivalence between Archimedean copula models and shared frailty models, e.g. between the Clayton-Oakes copula model and the shared gamma frailty model, has often been claimed in the literature. In this note we show that, in both the models, there is indeed a well-known equivalence between the copula functions; the modeling of the marginal survival functions, however, is quite different. The latter fact leads to different joint survival functions.