发展中国家技术引进的吸收-扩散问题研究

世界经济发展史经验表明后进国家通过积极引进发达国家先进技术,能够迅速摆脱落后,实现经济跳跃式发展.基于此,发展中国家十分重视从国外引进先进技术,并在实践中采取重大举措.但同时也应看到,由于受种种因素影响,发展中国家引进技术后,往往存在吸收和扩散能力低的问题,由此达不到技术引进的最佳效果.因此,探讨发展中国家技术引进吸收和扩散问题,具有十分重要的理论和现实意义.     

产业结构、工业化程度与地区差距的实证分析

用一种反映产业结构差异程度的新方法测算了我国2003年各省区产值结构和就业结构的整体水平,并据此对各省区的工业化程度进行了判断,随后对产业结构(工业化程度)和地区差距之间的关系进行了计量分析。实证结果表明我国各省区产业结构和工业化水平的差异程度是形成地区差距的重要原因,其意味着缩小地区差距的根本途径在于尽快实现落后地区的结构转型以及提升其工业化水平。     

彩票与国民经济的关联性分析

利用斯皮尔曼等级相关法,选取彩票发行量排在前10位的国家作为研究对象,对彩票的销售量与国民经济的几个重要指标之间的关系进行了分析。分析结果表明,彩票销售量与国家GDP总量有关,而与人均GDP和人均收入无关。在此基础上,对我国彩票市场的容量进行了分析。结论表明,我国彩票市场还有很大的潜力可以发掘。     

Na2CO3与NaHCO3溶液鉴别方法的设计与研究

成功地设计了氯化汞鉴别碳酸钠和碳酸氢钠溶液的实验方法,并从理论上论证了HgCl2鉴别Na2CO3和NaHCO3溶液的可能性.结果表明,加有氯化钠的氯化汞能有效地鉴别常量浓度的碳酸钠和碳酸氢钠溶液.该方法仪器简单操作方便,现象明显易觉察,成功率高效果好.     

地震区砂性土边坡滑动安全系数和可靠度

对地震区的边坡进行稳定性分析时,须计入地震力的作用;探讨用安全系数法和可靠性分析方法结合的方法,对地震区边坡进行滑动稳定性分析,既考虑了不确定性因素,又是对定值法的一种补充.     

Average kappa coefficient: a new measure to assess a binary test considering the losses associated with an erroneous classification

The weighted kappa coefficient of a binary diagnostic test (BDT) is a measure of performance of a BDT, and is a function of the sensitivity and the specificity of the diagnostic test, of the disease prevalence and the weighting index. Weighting index represents the relative loss between the false positives and the false negatives. In this study, we propose a new measure of performance of a BDT: the average kappa coefficient. This parameter is the average function of the weighted kappa coefficients and does not depend on the weighting index. We have studied three asymptotic confidence intervals (CIs) for the average kappa coefficient, Wald, logit and bias-corrected bootstrap, and we carried out some simulation experiments to study the asymptotic coverage of each of the three CIs. We have written a program in R, called ‘akcbdt’, to estimate the average kappa coefficient of a BDT. This program is available as supplementary material. The results were applied to two examples.     

Hermite polynomials and truncated trivariate normal distributions

The moments of a trivariate and in general of a multivariate normal distribution, which is truncated with respect to a single variable, are obtained by using properties of Hermite polynomials. An expression for the truncated correlation coefficient is derived in terms of the true population correlation coefficient and the truncation point. The values of this truncated correlation coefficient are tabulated for given values of the true correlation coefficient and a few selected values of the truncation point. A listing of the computer program for this purpose is also given.     

Robust modeling using the generalized epsilon-skew-t distribution

In this paper, an alternative skew Student-t family of distributions is studied. It is obtained as an extension of the generalized Student-t (GS-t) family introduced by McDonald and Newey [10]. The extension that is obtained can be seen as a reparametrization of the skewed GS-t distribution considered by Theodossiou [14]. A key element in the construction of such an extension is that it can be stochastically represented as a mixture of an epsilon-skew-power-exponential distribution [1] and a generalized-gamma distribution. From this representation, we can readily derive theoretical properties and easy-to-implement simulation schemes. Furthermore, we study some of its main properties including stochastic representation, moments and asymmetry and kurtosis coefficients. We also derive the Fisher information matrix, which is shown to be nonsingular for some special cases such as when the asymmetry parameter is null, that is, at the vicinity of symmetry, and discuss maximum-likelihood estimation. Simulation studies for some particular cases and real data analysis are also reported, illustrating the usefulness of the extension considered.     

Fully efficient estimation of coefficients of correlation in the presence of imputed survey data

Marginal imputation, that consists of imputing items separately, generally leads to biased estimators of bivariate parameters such as finite population coefficients of correlation. To overcome this problem, two main approaches have been considered in the literature: the first consists of using customary imputation methods such as random hot‐deck imputation and adjusting for the bias at the estimation stage. This approach was studied in Skinner & Rao 2002 . In this paper, we extend the results of Skinner & Rao 2002 to the case of arbitrary sampling designs and three variants of random hot‐deck imputation. The second approach consists of using an imputation method, which preserves the relationship between variables. Shao & Wang 2002 proposed a joint random regression imputation procedure that succeeds in preserving the relationships between two study variables. One drawback of the Shao–Wang procedure is that it suffers from an additional variability (called the imputation variance) due to the random selection of residuals, resulting in potentially inefficient estimators. Following Chauvet, Deville, & Haziza 2011 , we propose a fully efficient version of the Shao–Wang procedure that preserves the relationship between two study variables, while virtually eliminating the imputation variance. Results of a simulation study support our findings. An application using data from the Workplace and Employees Survey is also presented. The Canadian Journal of Statistics 40: 124–149; 2012 © 2011 Statistical Society of Canada     

物流产业集群依赖经济模型理论研究

产业集群经济理论在区域经济应用中越来越广泛。物流作为一种新型的产业经济,对产业集群越来越依赖。但在物流产业集群过程中,一系列因素严重阻碍了物流产业集群的发展。为解决此问题,对物流产业集群市场深入调研,从第一手资料中,分析并得出了物流产业集群依赖经济模型。