中国棘跳虫属记述(弹尾目 棘跳虫科)

本文记述了棘跳虫属我国已记录的11个种,为供分类鉴定所需,将其中10个常见种的形态特征进行了描述,并整理出了这10个种的检索表。     

C—代数的特征矩阵的性质

本主讨论了C-代数的特征矩阵的性质,并获得了求特征矩阵的逆的一个方法。     

An R2criterion based on optimal predictors

The predictor that minimizes mean-squared prediction error is used to derive a goodness-of-fit measure that offers an asymptotically valid model selection criterion for a wide variety of regression models. In particular, a new goodness-of-fit criterion (cr²) is proposed for censored or otherwise limited dependent variables. The new goodness-of-fit measure is then applied to the analysis of duration.     

Using unlabelled data to update classification rules with applications in food authenticity studies

Summary.  An authentic food is one that is what it purports to be. Food processors and consumers need to be assured that, when they pay for a specific product or ingredient, they are receiving exactly what they pay for. Classification methods are an important tool in food authenticity studies where they are used to assign food samples of unknown type to known types. A classification method is developed where the classification rule is estimated by using both the labelled and the unlabelled data, in contrast with many classical methods which use only the labelled data for estimation. This methodology models the data as arising from a Gaussian mixture model with parsimonious covariance structure, as is done in model-based clustering. A missing data formulation of the mixture model is used and the models are fitted by using the EM and classification EM algorithms. The methods are applied to the analysis of spectra of food-stuffs recorded over the visible and near infra-red wavelength range in food authenticity studies. A comparison of the performance of model-based discriminant analysis and the method of classification proposed is given. The classification method proposed is shown to yield very good misclassification rates. The correct classification rate was observed to be as much as 15% higher than the correct classification rate for model-based discriminant analysis.     

世界城市研究历程与分类体系综述

世界城市研究的兴起主要建立在西方发达国家城市发展的基础上,对世界城市的相关概念,研究历程,分类指标及等级体系进行国外文献研究分析,对于我国的世界城市建设及学术研究意义重大。通过世界城市的研究历程可以发现,不同的研究视角往往会产生不同的分类指标体系,而当今世界城市的分类标准正日趋呈现综合化。     

《核电档案分类准则及编码规则》的修订建议

《核电档案分类准则及编码规则》的实施解决了国内核电企业档案分类与编码的行业标准有与无的问题,固化了国内核电企业档案管理对文件分类与编码成果的继承要求,拓展了国内核电企业档案分类与编码的实践空间.面对核电行业信息化及职能管理变化趋势,后续修订需进一步体现档案类目设置的扁平化,强化二级综合类的设置,保证职能分类的一致性,容纳文件编码与档案编码的同一性做法。     

Classification of Observations into One of Two Artificially Dichotomized Classes by Using a Normal Screening Variable

This article considers a problem of normal based two group classification when the groups are artificially dichotomized by a screening variable. Each group distribution is derived and the best regions for the classification are obtained. These derivations yield yet another classification rule. The rule is studied from several aspects such as the distribution of the rule, the optimal error rate, and the testing of a hypothesis. This article gives relationships among these aspects along with the investigation of the performance of the rule. The classification method and ideas are illustrated in detail with two examples.     

FINITE MIXTURE OF CERTAIN DISTRIBUTIONS

ABSTRACT

A two parameter extended form of standard gamma function is suggested which provide extra flexibility to the density function over positive range. A finite mixture of beta distribution is defined by using the suggested extended form. The shape of density function of extended gamma distribution and also that of finite mixture of beta distribution for various values of the parameters are shown. Inverted distribution of extended gamma and that of finite mixture of beta distribution are given.     

Asymptotic convergence of dimension reduction based boosting in classification

In high dimensional classification problem, two stage method, reducing the dimension of predictor first and then applying the classification method, is a natural solution and has been widely used in many fields. The consistency of the two stage method is an important issue, since errors induced by dimension reduction method inevitably have impacts on the following classification method. As an effective method for classification problem, boosting has been widely used in practice. In this paper, we study the consistency of two stage method–dimension reduction based boosting algorithm (briefly DRB) for classification problem. Theoretical results show that Lipschitz condition on the base learner is required to guarantee the consistency of DRB. This theoretical findings provide useful guideline for application.