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Hauptverfasser: Vidal, Marc, Leman, Marc, Aguilera, Ana M.
Format: Preprint
Veröffentlicht: 2024
Schlagworte:
Online-Zugang:https://arxiv.org/abs/2412.17971
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author Vidal, Marc
Leman, Marc
Aguilera, Ana M.
author_facet Vidal, Marc
Leman, Marc
Aguilera, Ana M.
contents We develop a theory for functional independent component analysis in an infinite-dimensional framework using Sobolev spaces that accommodate smoother functions. The notion of penalized kurtosis is introduced motivated by Silverman's method for smoothing principal components. This approach allows for a classical definition of independent components obtained via projection onto the eigenfunctions of a smoothed kurtosis operator mapping a whitened functional random variable. We discuss the theoretical properties of this operator in relation to a generalized Fisher discriminant function and the relationship it entails with the Feldman-Hájek dichotomy for Gaussian measures, both of which are critical to the principles of functional classification. The proposed estimators are a particularly competitive alternative in binary classification of functional data and can eventually achieve the so-called near-perfect classification, which is a genuine phenomenon of high-dimensional data. Our methods are illustrated through simulations, various real datasets, and used to model electroencephalographic biomarkers for the diagnosis of depressive disorder.
format Preprint
id arxiv_https___arxiv_org_abs_2412_17971
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Functional independent component analysis by choice of norm: a framework for near-perfect classification
Vidal, Marc
Leman, Marc
Aguilera, Ana M.
Statistics Theory
46N30, 47A52, 60G15
We develop a theory for functional independent component analysis in an infinite-dimensional framework using Sobolev spaces that accommodate smoother functions. The notion of penalized kurtosis is introduced motivated by Silverman's method for smoothing principal components. This approach allows for a classical definition of independent components obtained via projection onto the eigenfunctions of a smoothed kurtosis operator mapping a whitened functional random variable. We discuss the theoretical properties of this operator in relation to a generalized Fisher discriminant function and the relationship it entails with the Feldman-Hájek dichotomy for Gaussian measures, both of which are critical to the principles of functional classification. The proposed estimators are a particularly competitive alternative in binary classification of functional data and can eventually achieve the so-called near-perfect classification, which is a genuine phenomenon of high-dimensional data. Our methods are illustrated through simulations, various real datasets, and used to model electroencephalographic biomarkers for the diagnosis of depressive disorder.
title Functional independent component analysis by choice of norm: a framework for near-perfect classification
topic Statistics Theory
46N30, 47A52, 60G15
url https://arxiv.org/abs/2412.17971