Backfitting Random Varying-Coefficient Models with Time-Dependent Smoothing Covariates

Abstract.  In this paper, we propose a random varying-coefficient model for longitudinal data. This model is different from the standard varying-coefficient model in the sense that the time-varying coefficients are assumed to be subject-specific, and can be considered as realizations of stochastic processes. This modelling strategy allows us to employ powerful mixed-effects modelling techniques to efficiently incorporate the within-subject and between-subject variations in the estimators of time-varying coefficients. Thus, the subject-specific feature of longitudinal data is effectively considered in the proposed model. A backfitting algorithm is proposed to estimate the coefficient functions. Simulation studies show that the proposed estimation methods are more efficient in finite-sample performance compared with the standard local least squares method. An application to an AIDS clinical study is presented to illustrate the proposed methodologies.     

在中国特色社会主义新起点上推进新的思想解放

解放思想，是党的思想路线的本质要求，是我们应对前进道路上各种新情况新问题、不断开创事业新局面的一大法宝，是中国特色社会主义的思想精髓。要把中国特色社会主义事业不断推向前进，必须在新起点上推进新的思想解放。     

对基础研究投入问题的思考

文章首先从公共财政的角度对基础研究的投入进行分析,其次从布什和斯托克斯的科研模式角度对基础研究的投入进行分析。在此基础上对加大我国基础研究的投入提出了相关建议。     

Local influence in multilevel models

The authors study the local influence of observations in multilevel regression models. To this end, they perturb simultaneously the variances, responses and design matrix. To measure the local change caused by these perturbations, they use generalized Cook statistics for the fixed and random parameter estimates. Closed form local influence measures also allow them to assess the joint influence of various observations. They suggest a simple computation method and illustrate their results using two examples.     

城市景观河流生态修复的产出研究及有效性可靠性检验——基于上海城市内河水质改善价值评估的实证分析

意愿价值评估法(CVM)为具有显著外部性的生态环境服务的价值评估提供可能,但只有经过有效性和可靠性检验的CVM成果才能应用于环境公共政策与治理。本文以CVM评价上海市城市景观内河——漕河泾港的生态恢复的产出,在国内经常采用的线形对数模型基础上,加入二值响应的Logit概率模型对受访者社会经济变量进行回归分析,验证本次CVM应用的理论有效性。回归中首次引入反映我国特殊社会结构的户籍变量、收入差距变量两者的交互项,并纳入间接反映环境问题历史成因的居民沿河居住期变量,以验证调查结果与一般经济理论的相容性和与我国特殊社会构成、经济态势以及环境历史成因的吻合性。以预调查和正式调查为试验—复试样本验证了研究结果的可靠性。结果表明:平均支付意愿是160元/(a.户),改善漕河泾水环境的年经济效益至少在6.1×106元。     

Modelling heterogeneous space–time occurrences of earthquakes and its residual analysis

Summary. Earthquake intensities are modelled as a function of previous activity whose specific form is based on established empirical laws in seismology, but whose parameter values can vary from place to place. This model is used for characterizing regional features of seismic activities in and around Japan, and also for exploring regions where the actual seismicity rate systematically deviates from that of the modelled rate.     

如何行成关系数据模型到面向对象数据模型的映射

关系数据模型是基于记录的基本数据模型;面向对象数据模型是基于对象的基本数据模型;两种数据模型在某种程度上应存在相互映射和相互转变的可能性,它们的相互映射和相互转变将使关系数据库和面向对象数据库之间的转变成为可能。     

我国会计电算化发展研究及其策略

随着电子信息产业的不断发展,会计电算化在社会经济中的运用越来越广泛,随之而来的如何发展我国会计电算化的问题也就越来越引起人们的关注。文章就此深入分析了我国会计电算化发展的现状与存在问题,并结合我国国情提出若干对策与策略。     

Bias Correction in the Dynamic Panel Data Model with a Nonscalar Disturbance Covariance Matrix

Approximation formulae are developed for the bias of ordinary and generalized Least Squares Dummy Variable (LSDV) estimators in dynamic panel data models. Results from Kiviet [Kiviet, J. F. (1995), on bias, inconsistency, and efficiency of various estimators in dynamic panel data models, J. Econometrics68:53-78; Kiviet, J. F. (1999), Expectations of expansions for estimators in a dynamic panel data model: some results for weakly exogenous regressors, In: Hsiao, C., Lahiri, K., Lee, L-F., Pesaran, M. H., eds., Analysis of Panels and Limited Dependent Variables, Cambridge: Cambridge University Press, pp. 199-225] are extended to higher-order dynamic panel data models with general covariance structure. The focus is on estimation of both short- and long-run coefficients. The results show that proper modelling of the disturbance covariance structure is indispensable. The bias approximations are used to construct bias corrected estimators which are then applied to quarterly data from 14 European Union countries. Money demand functions for M1, M2 and M3 are estimated for the EU area as a whole for the period 1991: I-1995: IV. Significant spillovers between countries are found reflecting the dependence of domestic money demand on foreign developments. The empirical results show that in general plausible long-run effects are obtained by the bias corrected estimators. Moreover, finite sample bias, although of moderate magnitude, is present underlining the importance of more refined estimation techniques. Also the efficiency gains by exploiting the heteroscedasticity and cross-correlation patterns between countries are sometimes considerable.     

名词性复合词的意义建构诸理论述评

名词性复合词的意义建构是一个看似简单,实际上非常复杂的过程。传统语法把这一意义建构过程简单化,认为名词性复合词的意义等于各组成部分名词的意义总和。转换生成语言学家 意义特征理论学家也都提出了各自的理论解释,但都有很大的缺陷。概念合成语言学理论对名词性复合词的意义建构做出了比较完整的理论解释,但也有待于进一步的改进。