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Full-Text Articles in Physical Sciences and Mathematics
On Nonparametric Comparison Of Images And Regression Surfaces, Xiao-Feng Wang, Deping Ye
On Nonparametric Comparison Of Images And Regression Surfaces, Xiao-Feng Wang, Deping Ye
Xiaofeng Wang
Multivariate local regression is an important tool for image processing and analysis. In many practical biomedical problems, one is often interested in comparing a group of images or regression surfaces. In this paper, we extend the existing method of testing the equality of nonparametric curves by Dette and Neumeyer (2001) and consider a test statistic by means of an L2-distance in the multi-dimensional case under a completely heteroscedastic nonparametric model. The test statistic is also extended to be used in the case of spatial correlated errors. Two bootstrap procedures are described in order to approximate the critical values of the …
Estimating Smooth Distribution Function In The Presence Of Heteroscedastic Measurement Errors, Xiao-Feng Wang, Zhaozhi Fan, Bin Wang
Estimating Smooth Distribution Function In The Presence Of Heteroscedastic Measurement Errors, Xiao-Feng Wang, Zhaozhi Fan, Bin Wang
Xiaofeng Wang
Measurement error occurs in many biomedical fields. The challenges arise when errors are heteroscedastic since we literally have only one observation for each error distribution. This paper concerns the estimation of smooth distribution function when data are contaminated with heteroscedastic errors. We study two types of methods to recover the unknown distribution function: a Fourier-type deconvolution method and a simulation extrapolation (SIMEX) method. The asymptotics of the two estimators are explored and the asymptotic pointwise confidence bands of the SIMEX estimator are obtained. The finite sample performances of the two estimators are evaluated through a simulation study. Finally, we illustrate …