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31.
Nicolas W. Hengartner Marten H. Wegkamp Eric Matzner-Løber 《Journal of the Royal Statistical Society. Series B, Statistical methodology》2002,64(4):791-804
Summary. The paper presents a general strategy for selecting the bandwidth of nonparametric regression estimators and specializes it to local linear regression smoothers. The procedure requires the sample to be divided into a training sample and a testing sample. Using the training sample we first compute a family of regression smoothers indexed by their bandwidths. Next we select the bandwidth by minimizing the empirical quadratic prediction error on the testing sample. The resulting bandwidth satisfies a finite sample oracle inequality which holds for all bounded regression functions. This permits asymptotically optimal estimation for nearly any regression function. The practical performance of the method is illustrated by a simulation study which shows good finite sample behaviour of our method compared with other bandwidth selection procedures. 相似文献
32.
Typically, parametric approaches to spatial problems require restrictive assumptions. On the other hand, in a wide variety of practical situations nonparametric bivariate smoothing techniques has been shown to be successfully employable for estimating small or large scale regularity factors, or even the signal content of spatial data taken as a whole.We propose a weighted local polynomial regression smoother suitable for fitting of spatial data. To account for spatial variability, we both insert a spatial contiguity index in the standard formulation, and construct a spatial-adaptive bandwidth selection rule. Our bandwidth selector depends on the Gearys local indicator of spatial association. As illustrative example, we provide a brief Monte Carlo study case on equally spaced data, the performances of our smoother and the standard polynomial regression procedure are compared.This note, though it is the result of a close collaboration, was specifically elaborated as follows: paragraphs 1 and 2 by T. Sclocco and the remainder by M. Di Marzio. The authors are grateful to the referees for constructive comments and suggestions. 相似文献
33.
Suppose G is a graph of p vertices. A proper labeling
f of G is a one-to-one mapping f:V(G)→{1,2,…,p}. The cyclic bandwidth sum of
G
with respect to
f is defined by CBS
f
(G)=∑
uv∈E(G)|f(v)−f(u)|
p
, where |x|
p
=min {|x|,p−|x|}. The cyclic bandwidth sum of G is defined by CBS(G)=min {CBS
f
(G): f is a proper labeling of G}. The bandwidth sum of
G
with respect to
f is defined by BS
f
(G)=∑
uv∈E(G)|f(v)−f(u)|. The bandwidth sum of G is defined by BS(G)=min {BS
f
(G): f is a proper labeling of G}. In this paper, we give a necessary and sufficient condition for BS(G)=CBS(G), and use this to show that BS(T)=CBS(T) when T is a tree. We also find cyclic bandwidth sums of complete bipartite graphs.
Dedicated to Professor Frank K. Hwang on the occasion of his 65th birthday.
Supported in part by the National Science Council under grants NSC91-2115-M-156-001. 相似文献
34.
This paper considers an inventory system with non-instantaneous deteriorating item in which demand rate is a function of advertisement of an item and selling price. This paper aids the retailer in maximizing the total profit by determining optimal inventory and marketing parameters. In contrast to previous inventory models, an arbitrary holding cost rate and arbitrary deterioration rate have been incorporated to provide general framework to the model. First, a mathematical model is formulated and then some useful theoretical results have been framed to characterize the optimal solutions. The necessary and sufficient conditions for the existence and uniqueness of the optimal solutions are also derived. An algorithm is designed to find the optimum solutions of the proposed model. Numerical examples are included to illustrate the algorithmic procedure and the effects of key parameters are studied to analyze the behavior of the model. 相似文献
35.
We obtain the rates of pointwise and uniform convergence of multivariate kernel density estimators using a random bandwidth vector obtained by some data-based algorithm. We are able to obtain faster rate for pointwise convergence. The uniform convergence rate is obtained under some moment condition on the marginal distribution. The rates are obtained under i.i.d. and strongly mixing type dependence assumptions. 相似文献
36.
倪仁兴 《绍兴文理学院学报》2001,21(9):93-97
从两个不同的角度浅议实变函数与数学分析间的联系一、数学分析的内容与方法是研究实变函数的重要手段;二、用实变函数理论可以透视数学分析. 相似文献
37.
Gaëlle Chagny 《Scandinavian Journal of Statistics》2015,42(2):336-360
In this work, we develop a method of adaptive non‐parametric estimation, based on ‘warped’ kernels. The aim is to estimate a real‐valued function s from a sample of random couples (X,Y). We deal with transformed data (Φ(X),Y), with Φ a one‐to‐one function, to build a collection of kernel estimators. The data‐driven bandwidth selection is performed with a method inspired by Goldenshluger and Lepski (Ann. Statist., 39, 2011, 1608). The method permits to handle various problems such as additive and multiplicative regression, conditional density estimation, hazard rate estimation based on randomly right‐censored data, and cumulative distribution function estimation from current‐status data. The interest is threefold. First, the squared‐bias/variance trade‐off is automatically realized. Next, non‐asymptotic risk bounds are derived. Lastly, the estimator is easily computed, thanks to its simple expression: a short simulation study is presented. 相似文献
38.
We consider the problem of variable selection in high-dimensional partially linear models with longitudinal data. A variable selection procedure is proposed based on the smooth-threshold generalized estimating equation (SGEE). The proposed procedure automatically eliminates inactive predictors by setting the corresponding parameters to be zero, and simultaneously estimates the nonzero regression coefficients by solving the SGEE. We establish the asymptotic properties in a high-dimensional framework where the number of covariates pn increases as the number of clusters n increases. Extensive Monte Carlo simulation studies are conducted to examine the finite sample performance of the proposed variable selection procedure. 相似文献
39.
扩频通信在无线局域网中的应用 总被引:4,自引:0,他引:4
吴凡 《浙江树人大学学报》2005,5(4):99-102
阐述目前无线局域网的特点和主要传输方式及扩频通信的主要工作原理,并就直接序列扩频、跳频扩频、跳时扩频和脉冲线形扩频四种扩频技术工作原理、扩频技术的四大特点和扩频技术在无线局域网中的应用前景等作了介绍. 相似文献
40.
The estimation of the means of the bivariate normal distribution, based on a sample obtained using a modification of the moving
extreme ranked set sampling technique (MERSS) is considered. The modification involves using a concomitant random variable.
Nonparametric-type methods as well as the maximum likelihood estimation are considered. The estimators obtained are compared
to their counterparts based on simple random sampling (SRS). It appears that the suggested estimators are more efficient.
Also, MERSS with concomitant variable is easier to use in practice than the usual ranked set sampling (RSS) with concomitant
variable. The issue of robustness of the procedure is addressed. Real trees data set is used for illustration. 相似文献