Abstract
Kernel estimates of a regression operator are investigated when the explanatory variable is of functional type. The bandwidths are locally chosen by a data-driven method based on the minimization of a functional version of a cross-validated criterion. A short asymptotic theoretical support is provided and the main body of this paper is devoted to various finite sample size applications. In particular, it is shown through some simulations, that a local bandwidth choice enables to capture some underlying heterogeneous structures in the functional dataset. As a consequence, the estimation of the relationship between a functional variable and a scalar response, and hence the prediction, can be significantly improved by using local smoothing parameter selection rather than global one. This is also confirmed from a chemometrical real functional dataset. These improvements are much more important than in standard finite dimensional setting.
Similar content being viewed by others
References
Cardot H, Ferraty F, Sarda P (2003) Spline estimators for the functional linear model. Stat Sin 13(3):571–591
Ferraty F, Vieu P (2004) Nonparametric models for functional data, with application in regression, time series prediction and curve discrimination. J Nonparametric Stat 16(1–2):111–125
Ferraty F, Vieu P (2006) Nonparametric functional data analysis: theory and practice. Springer, Springer Series in Statistics, New York
Grenander U (1963) Probabilities on algebraic structures. Wiley, New York
Härdle W, Bowman A (1988) Bootrapping in nonparametric regression: local adaptive smoothing and confidence bands. J Am Stat Assoc 83:102–110
Härdle W, Marron JS (1985) Optimal bandwidth selection in nonparametric regression function estimation. Ann Stat 13(4):1465–1481
Marron JS, Härdle W (1986) Random approximations to some measures of accuracy in nonparametric curve estimation. J Multivar Anal 20:91–113
Müller HG, Stadtmüller U (1987) Variable bandwidth kernel estimators of regression curves. Ann Stat 15:182–201
Nadaraya EA (1964) On estimating regression. Theory Probab. Appl. 9:141–142
Rachdi M, Vieu P (2006) Nonparametric regression for functional data: automatic smoothing parameter selection. J Stat Plann Inference (in press)
Ramsay J, Silverman B (1997) Functional data analysis. Springer, Springer Series in Statistics, New York
Ramsay J, Silverman B (2002) Applied functional data analysis. Methods and case studies. Springer, Springer Series in Statistics, New York
Vieu P (1991) Nonparametric regression: optimal local bandwidth choice. J R Stat Soc 53(2): 453–464
Watson GS (1964) Smooth regression analysis. Sankhya Ser. A 26:359–372
Whittle P (1960) Bounds for the moments of linear and quadratic forms in independent random variables (in russian). Teor. Verojatnost. I Primenen, 331–335. Engl. Transl. Theory Probab. Appl. 5, pp 302–305
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Benhenni, K., Ferraty, F., Rachdi, M. et al. Local smoothing regression with functional data. Computational Statistics 22, 353–369 (2007). https://doi.org/10.1007/s00180-007-0045-0
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00180-007-0045-0