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51.
语词组合在具体微观环节上是呈线性延伸的,但是从整体上看,这种线性组合则有时呈现出一定的非线性特征。非线性特征离不开语境。语符的表达往往是诉诸线性组合完成的,但是语符的理解则不尽然,它有时需要以非线性的方式理解,形成理解上的"循环",表现出线性组合的非线性特征, 体现出表达和接受的动态非线性关系。  相似文献   
52.
Let fn(x) be the univariate k-nearest neighbor (k-NN) density estimate proposed by Loftsgaarden and Quesenberry (1965). By using similar techniques as in Bahadur's representation of sample quantiles (1966), and by the recent results on the oscillation of empirical processes by Stute (1982), we derive the rate of strong uniform convergence of fn(x) on some suitably chosen interval Jδ. Some comparison with the kernel estimates is given, as well as the choice of the bandwidth sequence relative to the sample size.  相似文献   
53.
Recursive estimates of a probability density function (pdf) are known. This paper presents recursive estimates of a derivative of any desired order of a pdf. Let f be a pdf on the real line and p?0 be any desired integer. Based on a random sample of size n from f, estimators f(p)n of f(p), the pth order derivatives of f, are exhibited. These estimators are of the form n?1∑nj=1δjp, where δjp depends only on p and the jth observation in the sample, and hence can be computed recursively as the sample size increases. These estimators are shown to be asymptotically unbiased, mean square consistent and strongly consistent, both at a point and uniformly on the real line. For pointwise properties, the conditions on f(p) have been weakened with a little stronger assumption on the kernel function.  相似文献   
54.
This study examined the development of baserate estimation skills for everyday social events and attitudes. Subjects in grades one, three, and six responded to questions concerning their own rates of behavior and attitudes, and their estimates of baserates of behaviors and attitudes for their classmates. The findings indicate a general increase in accuracy for the estimation of baserates throughout the elementary school years. In addition, younger subjects were less likely to make similar estimates for themselves and their classmates than were older respondents. Developmental changes in estimation accuracy are discussed in relation to task content, use of the response scale, correspondence between self-reports and estimates, and sample variability.  相似文献   
55.
For a moderate or large number of regression coefficients, shrinkage estimates towards an overall mean are obtained by Bayes and empirical Bayes methods. For a special case, the Bayes and empirical Bayes shrinking weights are shown to be asymptotically equivalent as the amount of shrinkage goes to zero. Based on comparisons between Bayes and empirical Bayes solutions, a modification of the empirical Bayes shrinking weights designed to guard against unreasonable overshrinking is suggested. A numerical example is given.  相似文献   
56.
The Dirichlet process prior allows flexible nonparametric mixture modeling. The number of mixture components is not specified in advance and can grow as new data arrive. However, analyses based on the Dirichlet process prior are sensitive to the choice of the parameters, including an infinite-dimensional distributional parameter G 0. Most previous applications have either fixed G 0 as a member of a parametric family or treated G 0 in a Bayesian fashion, using parametric prior specifications. In contrast, we have developed an adaptive nonparametric method for constructing smooth estimates of G 0. We combine this method with a technique for estimating α, the other Dirichlet process parameter, that is inspired by an existing characterization of its maximum-likelihood estimator. Together, these estimation procedures yield a flexible empirical Bayes treatment of Dirichlet process mixtures. Such a treatment is useful in situations where smooth point estimates of G 0 are of intrinsic interest, or where the structure of G 0 cannot be conveniently modeled with the usual parametric prior families. Analysis of simulated and real-world datasets illustrates the robustness of this approach.  相似文献   
57.
应用阅读法、评述法和归纳法对国内外20世纪90年代以来,尤其是近10年来定量研究农业现代化发展水平的成果进行梳理,从主要评价方法、指标系统的构建、指标权重的确定和目标值的确定4个维度对其进行归纳总结,探求农业现代化定量研究的规律。结果表明:目前国内农业现代化水平的定量研究应用最为广泛的方法是综合指标法;农业现代化评价有5个基本步骤;农业现代化评价指标体系一般包括农业生产条件等版块;评价指标标准值确定要动态化、紧密结合当地实际且要反映变化趋势。农业现代化定量研究中尚存在的问题是数据搜集和整理困难、对国外相关资料缺乏挖掘以及新的评价方法和工具亟待引入。  相似文献   
58.
ABSTRACT

In this article, we consider the estimation of R = P(Y < X), when Y and X are two independent three-parameter Lindley (LI) random variables. On the basis of two independent samples, the modified maximum likelihood estimator along its asymptotic behavior and conditional likelihood-based estimator are used to estimate R. We also propose sample-based estimate of R and the associated credible interval based on importance sampling procedure. A real life data set involving the times to breakdown of an insulating fluid is presented and analyzed for illustrative purposes.  相似文献   
59.
A general class of multiple logistic regression models is reviewed and an extension is proposed which leads to restricted maximum likelihood estimates of model parameters. Examples of thegeneral model are given, with an emphasis placed on the interpretation of the parameters in each case.  相似文献   
60.
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