On identification of transfer function models by biased regression methods

This paper investigates a biased regression approach to the preliminary estimation of the Box-Jenkins transfer function weights. Using statistical simulation to generate time series, 14 estimators (various OLS, ridge and principal components estimators) are compared in terms of MSE and standard error of the weight estimators. The estimators are investigated for different levels of multicollinearity, signal-to-noise ratio, number of independent variables, length of time series and number of lags included in the estimation. The results show that the ridge estimators nearly always give lower MSE than the OLS estimator, and in the computationally difficult cases give much lower MSE than the OLS estimator. The principal components estimators can give lower MSE than the OLS, but also higher values. All biased estimators nearly always give much lower estimated standard error than OLS when estimating the weights.     

A generalized Q–Q plot for longitudinal data

Most biomedical research is carried out using longitudinal studies. The method of generalized estimating equations (GEEs) introduced by Liang and Zeger [Longitudinal data analysis using generalized linear models, Biometrika 73 (1986), pp. 13–22] and Zeger and Liang [Longitudinal data analysis for discrete and continuous outcomes, Biometrics 42 (1986), pp. 121–130] has become a standard method for analyzing non-normal longitudinal data. Since then, a large variety of GEEs have been proposed. However, the model diagnostic problem has not been explored intensively. Oh et al. [Modeldiagnostic plots for repeated measures data using the generalized estimating equations approach, Comput. Statist. Data Anal. 53 (2008), pp. 222–232] proposed residual plots based on the quantile–quantile (Q–Q) plots of the χ²-distribution for repeated-measures data using the GEE methodology. They considered the Pearson, Anscombe and deviance residuals. In this work, we propose to extend this graphical diagnostic using a generalized residual. A simulation study is presented as well as two examples illustrating the proposed generalized Q–Q plots.     

A wavelet-based time-varying autoregressive model for non-stationary and irregular time series

In this work we propose an autoregressive model with parameters varying in time applied to irregularly spaced non-stationary time series. We expand all the functional parameters in a wavelet basis and estimate the coefficients by least squares after truncation at a suitable resolution level. We also present some simulations in order to evaluate both the estimation method and the model behavior on finite samples. Applications to silicates and nitrites irregularly observed data are provided as well.     

Power series estimator for binary data

There are several commonly used measures of association between treatment and control event rates in the population, including odds ratios, relative risk and number needed to treat. Conventionally those parameters are estimated by the sample proportion estimators. In this paper, we show that the sample proportional estimators tend to overestimate. Fortunately, those measurements are estimable by the power series estimators and they converge to UMVUE with a speed of convergency depending on big-O. For instance, it converges slowly for the number needed to treat if the difference between two sample proportions is close to zero.     

论2000版ISO9000族标准中的持续改进

2000版9000族标准的目的是有效性,而"有效性"的保证就是持续改进,因此, 持续改进是2000版9000族标准的根本。文章就持续改进的对策、持续改进与相关概念——纠 正措施、预防措施、改革创新的关系等内容进行了探讨。     

Green supply chain management innovation diffusion and its relationship to organizational improvement: An ecological modernization perspective

Drawing on diffusion of innovation and ecological modernization theories, we identify three types of industrial manufacturers, namely early adopters, followers, and laggards, based on the adoption of green supply chain management (GSCM) practices among Chinese manufacturers. Test results indicate that differences exist between the three types of GSCM adopters in terms of their environmental, operational, and economic performance. Understanding how Chinese manufacturers adopt GSCM practices and if this adoption affects their performance contributes theoretical advancement to the diffusion of innovation theory. Practically, the results provide managerial insights for manufacturers to benchmark for environmental management practices and performance improvement.     

我国宏观税负合理区间的分析与判断

运用计量分析方法,考察了1990-2010年我国税收收入和宏观税负的变动情况及趋势,并对税收收入与GDP总量进行了协整分析,证明了二者间存在长期稳定的关系。同时对我国宏观税负进行了时间序列分析,解释了我国宏观税负在不同时间段发展变化的规律及其原因,并结合国际间不同收入等级国家宏观税负之间的比较,分析了我国当前宏观税负水平的合理区间与合理性,指出在我国当前所处的发展阶段,宏观税负水平保持在23%～30%的区间内是较为合适的。     

“思想道德修养与法律基础”课实践教学刍议

思想道德修养与法律基础课程实践教学一直存在着形式化、简单化、敷衍应付的现象,要改变这种现状,必须要重视实践教学环节,创新实践教学理念。对此,提出了思想道德修养与法律基础课程实践教学的四条路径,一要充分利用和挖掘学校及学校所在地的优质资源,立足实际,开展实践教学活动;二要积极探索和拓展形式多样的实践教学活动,让学生在实践中学会做人、做事;三要加大投入,建立相对固定的实践教学基地,让实践教学常态化;四要建立多元化的实践教学评价体系,督促学生积极主动地参与实践。     

基于小波神经网络的国际铀资源价格趋势分析

铀资源是核能发展的物质基础。研究国际铀资源价格的走势对制定我国核能开发及利用的政策和发展规划具有重要的参考价值。构建小波神经网络,预测了国际铀资源价格的趋势。通过比较发现小波神经网络的预测精度高于与之结构相同的传统BP网络以及时间序列模型。研究表明短期内国际铀资源价格将呈下降趋势,而2至5年内将呈现先抑后扬的趋势,但相比2006-2007年仍处于价格的低位,建议在这一时期逐步增加铀资源的战略储备。     

Change-in-mean problem for long memory time series models with applications

Test and estimation procedures for detecting a change in the mean are proposed in infinite moving average long memory time series models. The asymptotic properties of the test statistics and the change-point estimators are investigated. The method is illustrated through the analysis of real data sets from econometrics and climatology.