This paper introduces a Pade-type approximation for an unknown regression function in a nonparametric regression model. This newly introduced approximation provides a linear model with multi-collinearities and errors ...
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This paper introduces a Pade-type approximation for an unknown regression function in a nonparametric regression model. This newly introduced approximation provides a linear model with multi-collinearities and errors in all its variables. To deal with these issues, we used the truncated total least squares (TTLS) method. The efficient implementation of a Pade-type method using TTLS depends on choosing a truncation level. To provide an optimum truncation level for this method, we update the conventional parameter selection methods, including the generalized cross validation (GCV), improved version of the Akaike information criterion (AICc), restricted maximum likelihood (REML), Bayesian information criterion (BIC), and Mallows' C-p criterion. The primary aim of this study is to compare the performances of these level selection methods. A Monte Carlo simulation and a real data example are performed to illustrate the ideas in the paper. The results confirm that the GCV and AICc slightly outperform the other methods, especially when sample sizes are small and large, respectively.
A key issue in statistics and machine learning is to automatically select the "right" model complexity, e.g., the number of neighbors to be averaged over in k nearest neighbor (kNN) regression or the polynom...
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A key issue in statistics and machine learning is to automatically select the "right" model complexity, e.g., the number of neighbors to be averaged over in k nearest neighbor (kNN) regression or the polynomial degree in regression with polynomials. We suggest a novel principle - the Loss Rank Principle (LoRP) - for model selection in regression and classification. It is based on the loss rank, which counts how many other (fictitious) data would be fitted better. LoRP selects the model that has minimal loss rank. Unlike most penalized maximum likelihood variants (AIC, BIC, MDL), LoRP depends only on the regression functions and the loss function. It works without a stochastic noise model, and is directly applicable to any non-parametric regressor, like kNN. (C) 2009 Elsevier B.V. All rights reserved.
Enhancement of insulation performance has been a long-lasting problem for vacuum interrupter (VI) design. Traditional design focuses on reducing the maximal electric field strength (EFS);however, the distribution patt...
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Enhancement of insulation performance has been a long-lasting problem for vacuum interrupter (VI) design. Traditional design focuses on reducing the maximal electric field strength (EFS);however, the distribution pattern of electric field also plays an important role in insulating efficiency. A method based on region segmentation is proposed to modify the electric field distribution. By dividing the electric field area, the regression function derived from orthogonal experimental design is established for each unit to reveal the relationship between the structure parameters of VI and EFS. Then the target EFS distribution is designed, and the optimal solution set is obtained by practical swarm optimisation. Fuzzy cluster selection is introduced to choose the design scheme from the solution set. Comparison of the simulation and experimental results shows the effectiveness of the proposed method.
The main purpose is to estimate the regression function of a real random variable with functional explanatory variable by using a recursive nonparametric kernel approach. The mean square error and the almost sure conv...
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The main purpose is to estimate the regression function of a real random variable with functional explanatory variable by using a recursive nonparametric kernel approach. The mean square error and the almost sure convergence of a family of recursive kernel estimates of the regression function are derived. These results are established with rates and precise evaluation of the constant terms. Also, a central limit theorem for this class of estimators is established. The method is evaluated on simulations and real dataset studies. (C) 2013 Elsevier B.V. All rights reserved.
The random field (X-i, Y-i), is dependent and assumed to satisfy some mild mixing conditions. In this article, a Nadaraya-Watson regression estimator (N. W. R. E.) is established and investigated. We show that the dis...
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The random field (X-i, Y-i), is dependent and assumed to satisfy some mild mixing conditions. In this article, a Nadaraya-Watson regression estimator (N. W. R. E.) is established and investigated. We show that the distribution of the N. W. R. E. is asymptotically normal under some commonly used conditions.
We follow a learning theory viewpoint to study a family of learning schemes for regression related to positive linear operators in approximation theory. Such a learning scheme is generated from a random sample by a ke...
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We follow a learning theory viewpoint to study a family of learning schemes for regression related to positive linear operators in approximation theory. Such a learning scheme is generated from a random sample by a kernel function parameterized by a scaling parameter. The essential difference between this algorithm and the classical approximation schemes is the randomness of the sampling points, which breaks the condition of good distribution of sampling points often required in approximation theory. We investigate the efficiency of the learning algorithm in a regression setting and present learning rates stated in terms of the smoothness of the regression function, sizes of variances, and distances of kernel centers from regular grids. The error analysis is conducted by estimating the sample error and the approximation error. Two examples with kernel functions related to continuous Bernstein bases and Jackson kernels are studied in detail and concrete learning rates are obtained. (C) 2010 Elsevier Ltd. All rights reserved.
We are mainly concerned with the partially linear additive model defined for a measurable function psi : R-q -> R, by [Graphics] where (Z(i) = Z(1,i),...,Z(p,i))(T) and X-i=(X-1,X-i,...,X-i,(d))(T )are vectors of e...
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We are mainly concerned with the partially linear additive model defined for a measurable function psi : R-q -> R, by [Graphics] where (Z(i) = Z(1,i),...,Z(p,i))(T) and X-i=(X-1,X-i,...,X-i,(d))(T )are vectors of explanatory variables, beta=(beta(1), horizontexpressionl ellipsis ,beta(p))(?) is a vector of unknown parameters, m(1),..., m(d) are unknown univariate real functions, and epsilon(1), ...,epsilon(n) are independent random errors with mean zero, finite variances re and E(epsilon|X,Z)=0 a.s. Under some mild conditions, we present a sharp uniform-in-bandwidth limit law for the nonlinear additive components of the model estimated by the marginal integration device with the kernel method. We allow the bandwidth to varying within the complete range for which the estimator is consistent. We provide the almost sure simultaneous asymptotic confidence bands for the regression functions.
This article considers an adaptive method based on the relative error criteria to estimate the regression operator by a kernel smoothing. It is assumed that the variable of interest is subject to random right censorin...
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This article considers an adaptive method based on the relative error criteria to estimate the regression operator by a kernel smoothing. It is assumed that the variable of interest is subject to random right censoring and that the observations are from a stationary alpha-mixing process. The uniform almost sure consistency over a compact set with rate where we highlighted the covariance term is established. The simulation study indicates that the proposed approach has better performance in the presence of high level censoring and outliers in data to an existing classical method based on the least squares. An experiment prediction shows the quality of the relative error predictor.
We propose a likelihood ratio statistic for forming hypothesis tests and confidence intervals for a nonparametrically estimated univariate regression function, based on the shape restriction of concavity (alternativel...
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We propose a likelihood ratio statistic for forming hypothesis tests and confidence intervals for a nonparametrically estimated univariate regression function, based on the shape restriction of concavity (alternatively, convexity). Dealing with the likelihood ratio statistic requires studying an estimator satisfying a null hypothesis, that is, studying a concave least-squares estimator satisfying a further equality constraint. We study this null hypothesis least-squares estimator (NLSE) here, and use it to study our likelihood ratio statistic. The NLSE is the solution to a convex program, and we find a set of inequality and equality constraints that characterize the solution. We also study a corresponding limiting version of the convex program based on observing a Brownian motion with drift. The solution to the limit problem is a stochastic process. We study the optimality conditions for the solution to the limit problem and find that they match those we derived for the solution to the finite sample problem. This allows us to show the limit stochastic process yields the limit distribution of the (finite sample) NLSE. We conjecture that the likelihood ratio statistic is asymptotically pivotal, meaning that it has a limit distribution with no nuisance parameters to be estimated, which makes it a very effective tool for this difficult inference problem. We provide a partial proof of this conjecture, and we also provide simulation evidence strongly supporting this conjecture.
We introduce and study a local linear nonparametric regression estimator for censorship model. The main goal of this paper is, to establish the uniform almost sure consistency result with rate over a compact set for t...
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We introduce and study a local linear nonparametric regression estimator for censorship model. The main goal of this paper is, to establish the uniform almost sure consistency result with rate over a compact set for the new estimate. To support our theoretical result, a simulation study has been done to make comparison with the classical regression estimator.
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