Asymptotic test statistics for coefficients of variation

A one-sample asymptotically normal test statistic Is derived for testing the hypothesis that the coefficient of variation of a normal population is equal to a specified value. Based on this derivation, an asymptotically noraml two-sample test statistic and an asymptotically chi-square k-sample test statistic are derived for testing the hypothesis that the coefficients of variation of k ≥2 normal populations are equal. The two and k-sample test statistics allow for unequal sample sizes. Results of a simulation study which evaluate the size and power of the test statistics and compare the test statistics to earlier ones developed by McKay (1932) and Bennett (1976) are presented.     

Sampled autocovariance and autocorrelation results for linear time processes

We derive an exact formula for the covariance between the sampled autocovariances at any two lags for a finite time series realisation from a general stationary autoregressive moving average process. We indicate, through one particular example, how this result can be used to deduce analogous formulae for any nonstationary model of the ARUMA class, a generalisation of the ARIMA models. Such formulae then allow us to obtain approximate expressions for the convariances between all pairs of serial correlations for finite realisations from the ARUMA model. We also note that, in the limit as the series length n → ∞, our results for the ARMA class retrieve those of Bartlett (1946). Finally, we investigate an improvement to the approximation that is obtained by applying Bartlett's general asymptotic formula to finite series realisations. That such an improvement should exist can immediately be seen by consideration of out results for the simplest case of a white noise process. However, we deduce the final improved approapproximation, for general models, in two ways - from (corrected) results due to Davies and Newbold (1980), and by an alternative approach to theirs.     

萨特的思想与艺术

萨特存在主义的哲学思想主要由存在先于本质,自由选择理论和总体化观点三部分组成.萨特的哲学思想,不仅通过文学创作而以艺术的形式进行宣扬,也通过他对美和艺术的观点而得到深刻的诠释,它们共同构成三位一体的有机结构.     

数据修订、实时估计与时变参数货币政策规则抉择

本文拓展构建了后顾、同期和前瞻三种类型的货币政策规则,并基于实时数据和最终数据实证分析数据修订和实时估计对货币政策参数的影响效应。研究结果发现,数据修订对泰勒规则的影响取决于不同模型,而且在三种模型设定中,盯住产出缺口和通胀目标的时变参数均在不同程度上受数据修订的影响。特别是,对于最终数据,采用同期性货币政策规则展开估计最为有效;而对于实时数据,则基于后顾性货币政策规则模型估计是最佳的。最后,本文在数据选择和模型匹配上提出相应的对策建议。     

Can alternative Taylor-rule specifications describe Federal Reserve policy decisions?

We look at how well several alternative Taylor-rule specifications describe Federal Reserve policy decisions in real time, using the newly developed Giacomini and Rossi (2007) test for non-nested model selection in the presence of (possible) parameter instability. Further, we isolate those Taylor-rule features that are most important for achieving relatively strong real-time performance. Key features of our preferred rule, which is robust to changing economic conditions, are the partial adjustment of the federal funds rate toward an equilibrium rate that depends on the unemployment rate and forward-looking inflation measures. We conclude by presenting an empirical application to show the policy relevance of our preferred rule in the context of the 2008–2009 recession.     

复合指数函数泰勒系数之不等式

本文目的在综合叙述及推导复合指数函数的幂级数之系数间相关不等式．其特殊情形为Milin和lebejev首先证明，在单叶函数理论起着非常重要的作用．在此我们完全摆脱单叶函数关系叙述．     

《木马赢家》中语言建构的隐含男权

《木马赢家》是劳伦斯晚期著名的短篇小说。该小说被拍成了影片,还选进了校园课本,其影响非常巨大。小说讲述了小男孩保罗之死的故事,也因为小男孩的死,对母亲海斯特的评论大都持负面批判态度,却对父亲的“不在场”所隐含的男权关注甚少。分析文本,发现保罗之死与母亲并没有绝对的关系,而是小说中语言所形成的“男权象征体系”误导了读者,将母亲推向了审判席。     

泰勒展开图像插值的一个改进算法

待插像素邻域内像素点处泰勒展开式的算术平均会模糊插值图像边缘.文章提出一个改进算法，采用展开式与其灰度值之差绝对值最小的泰勒展开式近似待插像素的灰度值.这种方法充分考虑待插像素与其邻域的图像信息，获得清晰的插值图像边缘.数值实验证明：这种算法简单有效且易于实现.     

我国第一所西式大学——论澳门圣保禄学院的历史地位

澳门圣保禄学院是我国第一所西方式的高等学校。该学院培养了以利玛窦为代表的一大批东西方文化交流巨匠，对我国以至世界文化发展作出重要贡献。从１６ 世纪到１９ 世纪中叶，澳门是东西方文化交流的桥梁，该学院是建筑这座桥梁的基础。虽然该学院由耶稣会创办， 以培养传教士为主， 建立在葡萄牙人租用的土地上， 但这并不影响它的历史地位。