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41.
作为新批评派鼻祖的T·S·艾略特在他最重要的论文《传统与个人才能》一文中试图将文学理论、文学批评与文学史融合起来,提出了文学的"非个人化"特征,强调文学"传统"对个体作家所具有的决定性影响,并以此建构了他独特的文学史观和文学史评价标准,对推动20世纪西方文学史理论的发展作出了突出贡献,为我们在新世纪的文学史建设提供了具体而深刻的启迪。  相似文献   
42.
We consider the estimation of dynamic panel data models in the presence of incidental parameters in both dimensions: individual fixed‐effects and time fixed‐effects, as well as incidental parameters in the variances. We adopt the factor analytical approach by estimating the sample variance of individual effects rather than the effects themselves. In the presence of cross‐sectional heteroskedasticity, the factor method estimates the average of the cross‐sectional variances instead of the individual variances. The method thereby eliminates the incidental‐parameter problem in the means and in the variances over the cross‐sectional dimension. We further show that estimating the time effects and heteroskedasticities in the time dimension does not lead to the incidental‐parameter bias even when T and N are comparable. Moreover, efficient and robust estimation is obtained by jointly estimating heteroskedasticities.  相似文献   
43.
In statistical process control applications, the multivariate T 2 control chart based on Hotelling's T 2 statistic is useful for detecting the presence of special causes of variation. In particular, use of the T 2 statistic based on the successive differences covariance matrix estimator has been shown to be very effective in detecting the presence of a sustained step or ramp shift in the mean vector. However, the exact distribution of this statistic is unknown. In this article, we derive the maximum value of the T 2 statistic based on the successive differences covariance matrix estimator. This distributional property is crucial for calculating an approximate upper control limit of a T 2 control chart based on successive differences, as described in Williams et al. (2006 Williams , J. D. , Woodall , W. H. , Birch , J. B. , Sullivan , J. H. ( 2006 ). On the distribution of T 2 statistics based on successive differences . J. Qual. Technol. 38 : 217229 .[Taylor & Francis Online], [Web of Science ®] [Google Scholar]).  相似文献   
44.
A control procedure is presented in this article that is based on jointly using two separate control statistics in the detection and interpretation of signals in a multivariate normal process. The procedure detects the following three situations: (i) a mean vector shift without a shift in the covariance matrix; (ii) a shift in process variation (covariance matrix) without a mean vector shift; and (iii) both a simultaneous shift in the mean vector and covariance matrix as the result of a change in the parameters of some key process variables. It is shown that, following the occurrence of a signal on either of the separate control charts, the values from both of the corresponding signaling statistics can be decomposed into interpretable elements. Viewing the two decompositions together helps one to specifically identify the individual components and associated variables that are being affected. These components may include individual means or variances of the process variables as well as the correlations between or among variables. An industrial data set is used to illustrate the procedure.  相似文献   
45.
Finding the influence of traffic accident on the road is helpful to analyze the characteristics of traffic flow, and take reasonable and effective control measures. Here, the detrended fluctuation analysis method is applied to investigate the complexity of time series in mixed traffic flow with a blockage induced by an accident. As a parameter to depict the long-term evolutionary behavior of the time series in traffic flow, the scaling exponent is analyzed. According to the scaling exponent, it is shown that the traffic flow time series can display long-range correlation characteristics, short-range correlation characteristics, and non-power-law relation in the long-range correlation characteristics, which is strongly dependent on the entering probability of vehicle, the ratio of slow vehicle and the blockage duration time.  相似文献   
46.
Different methodologies for fault diagnosis in multivariate quality control have been proposed in recent years. These methods work in the space of the original measured variables and have performed reasonably well when there is a reduced number of mildly correlated quality and/or process variables with a well-conditioned covariance matrix. These approaches have been introduced by emphasizing their positive or negative virtues, generally on an individual basis, so it is not clear for the practitioner the best method to be used. This article provides a comprehensive study of the performance of diverse methodological approaches when tested on a large number of distinct simulated scenarios. Our primary aim is to highlight key weaknesses and strengths in these methods as well as clarifying their relationships and the requirements for their implementation in practice.  相似文献   
47.
In this paper we consider the issue of constructing retrospective T 2 control chart limits so as to control the overall probability of a false alarm at a specified value. We describe an exact method for constructing the control limits for retrospective examination. We then consider Bonferroni-adjustments to Alt's control limit and to the standard x 2 control limit as alternatives to the exact limit since it is computationally cumbersome to find the exact limit. We present the results of some simulation experiments that are carried out to compare the performance of these control limits. The results indicate that the Bonferroni-adjusted Alt's control limit performs better that the Bonferroni-adjusted x 2 control limit. Furthermore, it appears that the Bonferroni-adjusted Alt's control limit is more than adequate for controlling the overall false alarm probability at a specified value.  相似文献   
48.
鉴于信用证具有比较强的收汇保障的性能和贸易融资功能,因此也一直是我国出口企业贸易结算的首选,使用率高居90%。但是近年来,其结算的“霸主”地位不断弱化,并由此对我国外贸出口产生了较大的不利影响。本文探讨了其中具体的原因及影响,并辅以对策。  相似文献   
49.
Abstract

This paper examines the high dimensional asymptotics of the naive Hotelling T2 statistic. Naive Bayes has been utilized in high dimensional pattern recognition as a method to avoid singularities in the estimated covariance matrix. The naive Hotelling T2 statistic, which is equivalent to the estimator of the naive canonical correlation, is a statistically important quantity in naive Bayes and its high dimensional behavior has been studied under several conditions. In this paper, asymptotic normality of the naive Hotelling T2 statistic under a high dimension low sample size setting is developed using the central limit theorem of a martingale difference sequence.  相似文献   
50.
现有区域科技创新能力评价方法大多忽视了指标体系中各因素之间可能存在的相关关系和层级差异。结构方程建模能够过滤误差、同时考察不同层级变量间的直接作用与间接作用,找出变量间存在的内在结构关系,在分析区域科技创新能力评价指标体系各种变量间多种关系方面具有可行性和必要性。应用SEM时除了要注意选取恰当指标、构建合适模型以外,还应注意对样本容量、缺失数据的处理和信度效度的检验。  相似文献   
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