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51.
邱会中 《电子科技大学学报(社会科学版)》1989,(3)
n节连分式算法是一个实用的一维搜索方法。构造连分式插位函数时,部分分母的计算在该算法中占有较大的比重,本文通过对插值点先后顺序的有效安排,使得部分分母的计算量下降近三分之一。最后,对该算法可能遇到的数值困难提供了一个实施方案。 相似文献
52.
涂伟 《武汉科技大学学报(社会科学版)》2007,9(1):48-51
基于市场营销理论,对电子零售业(B2C)中交易成本和顾客价值两个概念进行分析,认为B2C降低交易成本并不一定能提高顾客价值,即并非线性相关。还有一个变量是顾客对交易成本的看重程度,在此基础上提出B2C交易成本与顾客价值关系的模型,并分析了此模型对B2C企业的意义。 相似文献
53.
Smoothing parameter selection in nonparametric regression using an improved Akaike information criterion 总被引:1,自引:0,他引:1
Clifford M. Hurvich Jeffrey S. Simonoff & Chih-Ling Tsai 《Journal of the Royal Statistical Society. Series B, Statistical methodology》1998,60(2):271-293
Many different methods have been proposed to construct nonparametric estimates of a smooth regression function, including local polynomial, (convolution) kernel and smoothing spline estimators. Each of these estimators uses a smoothing parameter to control the amount of smoothing performed on a given data set. In this paper an improved version of a criterion based on the Akaike information criterion (AIC), termed AICC , is derived and examined as a way to choose the smoothing parameter. Unlike plug-in methods, AICC can be used to choose smoothing parameters for any linear smoother, including local quadratic and smoothing spline estimators. The use of AICC avoids the large variability and tendency to undersmooth (compared with the actual minimizer of average squared error) seen when other 'classical' approaches (such as generalized cross-validation (GCV) or the AIC) are used to choose the smoothing parameter. Monte Carlo simulations demonstrate that the AICC -based smoothing parameter is competitive with a plug-in method (assuming that one exists) when the plug-in method works well but also performs well when the plug-in approach fails or is unavailable. 相似文献
54.
Naomi Altman 《Australian & New Zealand Journal of Statistics》2000,42(4):441-461
Both kriging and non-parametric regression smoothing can model a non-stationary regression function with spatially correlated errors. However comparisons have mainly been based on ordinary kriging and smoothing with uncorrelated errors. Ordinary kriging attributes smoothness of the response to spatial autocorrelation whereas non-parametric regression attributes trends to a smooth regression function. For spatial processes it is reasonable to suppose that the response is due to both trend and autocorrelation. This paper reviews methodology for non-parametric regression with autocorrelated errors which is a natural compromise between the two methods. Re-analysis of the one-dimensional stationary spatial data of Laslett (1994) and a clearly non-stationary time series demonstrates the rather surprising result that for these data, ordinary kriging outperforms more computationally intensive models including both universal kriging and correlated splines for spatial prediction. For estimating the regression function, non-parametric regression provides adaptive estimation, but the autocorrelation must be accounted for in selecting the smoothing parameter. 相似文献
55.
本文介绍了单线数字温度传感器DS18820的结构、特点、工作原理,设计了一种基于DS18820和AT89S52单片机的温度测量系统的硬件结构及汇蝙程序设计。 相似文献
56.
通过定义插值因子,对Hermite插值问题依次考虑满足插值结点x1;x1,x2;x1,x2,x3;…;x1,x2,…,xs处的插值条件,采用逐步迭代的方法构造插值多项式,得到插值多项式系数的递推公式.给出的数值例子验证了所给算法的有效性. 相似文献
57.
In this paper we discuss some distributional properties of quadratic functionals of the ordinary and fractional Brownian motions (fBms). As far as the ordinary Brownian motion (Bm) is concerned, those properties have been established extensively. A transition from the Bm to the fBm is not straightforward. Some difficulties associated with dealing with the fBm are explained, and a way to solving the problem is indicated, and some conjectures are given. 相似文献
58.
利用有理插值逼近回归函数,把最小二乘法和插值技术结合起来,充分利用已知信息,达到最佳逼近,通过实例,获得了很好的效果。 相似文献
59.
Marina S. Paez Dani GamermanFlávia M.P.F. Landim Esther Salazar 《Journal of statistical planning and inference》2008
In this work we present a flexible class of linear models to treat observations made in discrete time and continuous space, where the regression coefficients vary smoothly in time and space. This kind of model is particularly appealing in situations where the effect of one or more explanatory processes on the response present substantial heterogeneity in both dimensions. We describe how to perform inference for this class of models and also how to perform forecasting in time and interpolation in space, using simulation techniques. The performance of the algorithm to estimate the parameters of the model and to perform prediction in time is investigated with simulated data sets. The proposed methodology is used to model pollution levels in the Northeast of the United States. 相似文献
60.
基于B/S结构和.Net平台的研究生培养管理信息系统的设计 总被引:4,自引:0,他引:4
简要分析目前我校研究生培养管理系统的设计和使用现状,基于B/S结构的研究生培养管理信息系统提出了一些创新性的管理思路。 相似文献