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Functional Data Analysis

TLDR
In this article, the authors provide an overview of FDA, starting with simple statistical notions such as mean and covariance functions, then covering some core techniques, the most popular of which is functional principal component analysis (FPCA).
Abstract
With the advance of modern technology, more and more data are being recorded continuously during a time interval or intermittently at several discrete time points. These are both examples of functional data, which has become a commonly encountered type of data. Functional data analysis (FDA) encompasses the statistical methodology for such data. Broadly interpreted, FDA deals with the analysis and theory of data that are in the form of functions. This paper provides an overview of FDA, starting with simple statistical notions such as mean and covariance functions, then covering some core techniques, the most popular of which is functional principal component analysis (FPCA). FPCA is an important dimension reduction tool, and in sparse data situations it can be used to impute functional data that are sparsely observed. Other dimension reduction approaches are also discussed. In addition, we review another core technique, functional linear regression, as well as clustering and classification of functional d...

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Journal ArticleDOI

Exact tests for the means of Gaussian stochastic processes

TL;DR: In this article, the inferential properties of testing the means of Gaussian functional data, using a Mahalanobis type distance for Hilbert spaces, were investigated and the analytic power of exact and asymptotic tests, for the known and unknown covariance case, respectively.
Posted Content

Simultaneous Confidence Bands for Functional Data Using the Gaussian Kinematic Formula

TL;DR: In this article, simultaneous confidence bands (SCBs) for functional parameters using the Gaussian Kinematic formula of $t$-processes (tGKF) were constructed for diffusion tensor imaging (DTI) fibers.
Journal ArticleDOI

Differential kinematic features of the hyoid bone during swallowing in patients with Parkinson's disease.

TL;DR: Reduced horizontal displacement and velocity of the hyoid bone during the forward motion would be due to combined effects of disease and aging, whereas those over the initial backward motion may be considered specific to patients with PD.

A Spectral Representation of Kernel Stein Discrepancy with Application to Goodness-of-Fit Tests for Measures on Infinite Dimensional Hilbert Spaces

TL;DR: A novel spectral representation of KSD is provided, making KSD applicable to Hilbert-valued data and revealing the impact of kernel and Stein operator choice on the KSD.
Journal ArticleDOI

On functional data analysis and related topics

TL;DR: In this article , various contributions to the Special Issue of the Journal of Multivariate Analysis on Functional Data Analysis and some related topics including high-dimensional statistics and multivariate analysis of complex data are presented.
References
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Journal ArticleDOI

Nonlinear dimensionality reduction by locally linear embedding.

TL;DR: Locally linear embedding (LLE) is introduced, an unsupervised learning algorithm that computes low-dimensional, neighborhood-preserving embeddings of high-dimensional inputs that learns the global structure of nonlinear manifolds.
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A global geometric framework for nonlinear dimensionality reduction.

TL;DR: An approach to solving dimensionality reduction problems that uses easily measured local metric information to learn the underlying global geometry of a data set and efficiently computes a globally optimal solution, and is guaranteed to converge asymptotically to the true structure.
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Generalized Additive Models.

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Dynamic programming algorithm optimization for spoken word recognition

TL;DR: This paper reports on an optimum dynamic progxamming (DP) based time-normalization algorithm for spoken word recognition, in which the warping function slope is restricted so as to improve discrimination between words in different categories.
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Generalized Additive Models

TL;DR: The class of generalized additive models is introduced, which replaces the linear form E fjXj by a sum of smooth functions E sj(Xj), and has the advantage of being completely auto- matic, i.e., no "detective work" is needed on the part of the statistician.