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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

Circulating microvesicles correlate with radiation proctitis complication after radiotherapy

TL;DR: In this paper , the authors assessed the use of circulating microvesicles (MVs) as innovative biomarkers of radiation toxicity in a cohort of 208 patients with prostate adenocarcinoma overexposed to radiation.
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Multivariate functional data clustering using adaptive density peak detection

TL;DR: Wang et al. as discussed by the authors proposed a novel clustering method for multivariate functional data using an adaptive density peak detection technique based on the two measures of each functional data observation: the functional density estimate and the distance to the closest observation with a higher functional density.

An adaptive model checking test for functional linear model

Inglong, +1 more
TL;DR: An adaptive model checking test for FLM that combines regular moment- based and conditional moment-based tests, and achieves model adaptivity via the dimension of a residual-based subspace, which is promising in sufficient dimension reduction.
Posted Content

Concurrent Object Regression

TL;DR: In this paper, a new concurrent regression model is proposed to characterize the time-varying relation between an object in a general metric space (as response) and a vector in real values (as predictor) where concepts from Fr\'echet regression is employed.
Journal ArticleDOI

Conditional Independence Testing in Hilbert Spaces with Applications to Functional Data Analysis

TL;DR: In this paper , the authors study the problem of testing the null hypothesis that X and Y are conditionally independent given Z, where each of X, Y and Z may be functional random variables.
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.
Journal ArticleDOI

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.