产业集群培育与城市功能优化

产业集群对地区经济发展具有积极的作用.集群的形成是多种因素综合作用的结果,本质上依赖于城市功能的支持.城市功能是个系统概念,是要素、结构和支持体系的统一.按照系统性、个性化的原则优化城市功能,可有效培育产业集群,带动地区经济发展.     

Distributions of the ratios of independent beta variables and applications

We establish the exact expressions of X₁/X₂ and of X₁/(X₁+X₂), where X₁ and X₂ are independent beta random variables of the first type, and provide some of their applications, in reliability and availability.     

Estimation of odds ratios under order restrictions

A new method for estimating a set of odds ratios under an order restriction based on estimating equations is proposed. The method is applied to those of the conditional maximum likelihood estimators and the Mantel-Haenszel estimators. The estimators derived from the conditional likelihood estimating equations are shown to maximize the conditional likelihoods. It is also seen that the restricted estimators converge almost surely to the respective odds ratios when the respective sample sizes become large regularly. The restricted estimators are compared with the unrestricted maximum likelihood estimators by a Monte Carlo simulation. The simulation studies show that the restricted estimates improve the mean squared errors remarkably, while the Mantel-Haenszel type estimates are competitive with the conditional maximum likelihood estimates, being slightly worse.     

An additive subdistribution hazard model for competing risks data

The cumulative incidence function plays an important role in assessing its treatment and covariate effects with competing risks data. In this article, we consider an additive hazard model allowing the time-varying covariate effects for the subdistribution and propose the weighted estimating equation under the covariate-dependent censoring by fitting the Cox-type hazard model for the censoring distribution. When there exists some association between the censoring time and the covariates, the proposed coefficients’ estimations are unbiased and the large-sample properties are established. The finite-sample properties of the proposed estimators are examined in the simulation study. The proposed Cox-weighted method is applied to a competing risks dataset from a Hodgkin's disease study.     

我国政府不能放弃组织公有经济的职能

政府参与组织实体经济,是社会经济发展规律的内在要求,被社会主义市场经济的实践证明更能促进社会生产力的发展,由建立以公有制为主体的基本经济制度所决定。为此,我国政府要主动担责,不怕被问责,不怕被指责。     

从关联理论角度探讨话语标记语oh的语用功能

关联理论为探讨语言形式与话语理解之间的关系提供了理论框架。在该理论的基础上,从认知—语用的角度分析总结了话语标记语oh在言语交际中的六个语用功能:信息修正标记、话语延缓标记、话轮转换标记、信息追加标记、认可旧信息标记和获得新信息标记,进一步揭示了言语交际的动态性,以期帮助人们更好地生成理解话语。     

A Comparison of Hierarchical Methods for Clustering Functional Data

Functional data analysis (FDA)—the analysis of data that can be considered a set of observed continuous functions—is an increasingly common class of statistical analysis. One of the most widely used FDA methods is the cluster analysis of functional data; however, little work has been done to compare the performance of clustering methods on functional data. In this article, a simulation study compares the performance of four major hierarchical methods for clustering functional data. The simulated data varied in three ways: the nature of the signal functions (periodic, non periodic, or mixed), the amount of noise added to the signal functions, and the pattern of the true cluster sizes. The Rand index was used to compare the performance of each clustering method. As a secondary goal, clustering methods were also compared when the number of clusters has been misspecified. To illustrate the results, a real set of functional data was clustered where the true clustering structure is believed to be known. Comparing the clustering methods for the real data set confirmed the findings of the simulation. This study yields concrete suggestions to future researchers to determine the best method for clustering their functional data.     

中国经济发展中的深层次问题

中国经济正面临何去何从的方向性问题:是进一步深化改革,抓大放小,无为而治,让市场发挥越来越多的作用;还是国进民退,让政府主导经济,发挥更多的作用?答案无疑是前者。基于以上判断,中国经济的长期深层次根本问题在于:深层次制度障碍未破除,深层次市场化改革滞后,政府、社会与市场的治理边界界定不清晰、不合理。这就导致了三重三轻的不科学发展观:重政府轻市场、重国富轻民富、重发展轻服务。要解决这些深层次问题,下一步改革的关键在于深入推进政府职能的两个根本性转变:第一,从发展型政府向服务型政府转变;第二,从全能型政府向有限型政府转变。     

Bayesian Analysis in Regression Models Using Pseudo-Likelihoods

This article deals with the issue of using a suitable pseudo-likelihood, instead of an integrated likelihood, when performing Bayesian inference about a scalar parameter of interest in the presence of nuisance parameters. The proposed approach has the advantages of avoiding the elicitation on the nuisance parameters and the computation of multidimensional integrals. Moreover, it is particularly useful when it is difficult, or even impractical, to write the full likelihood function.

We focus on Bayesian inference about a scalar regression coefficient in various regression models. First, in the context of non-normal regression-scale models, we give a theroetical result showing that there is no loss of information about the parameter of interest when using a posterior distribution derived from a pseudo-likelihood instead of the correct posterior distribution. Second, we present non trivial applications with high-dimensional, or even infinite-dimensional, nuisance parameters in the context of nonlinear normal heteroscedastic regression models, and of models for binary outcomes and count data, accounting also for possibile overdispersion. In all these situtations, we show that non Bayesian methods for eliminating nuisance parameters can be usefully incorporated into a one-parameter Bayesian analysis.     

Elliptically contoured model and factorization of wllks1 A

In a series of papers, Kshirsagar (1964, 1971) and McHenry and Kshirsagar (1977), factorize Wilks' A into a number of factors and find the independent null multivariate beta densities of these factors. These factors are the likelihood ratio test criteria for testing the goodness of fit of certain assigned discriminant functions or canonical variables either in the space of independent or dependent variables. Essentially the factors of Wilks' A are the factors of certain multivariate beta distributed matrix or its determinant. The Bartlett decomposition of the underlying multivariate beta distribution into independent factors determines the distribution of these factors. The present paper generalizes Kshirsagar's (1971) normal theory to the elliptically contoured model, and shows that his results are null robust for the elliptically contoured model.