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We consider the statistical problem of estimating constituent curves from observations of their aggregated curves, referred to as \textit{aggregated functional data}, in models with strictly positive random errors following a Gamma…

The present work describes simulation studies to compare the performances of bayesian wavelet shrinkage methods in estimating component curves from aggregated functional data. To do so, five methods were considered: the bayesian shrinkage…

Methodology · Statistics 2022-10-12 Alex Rodrigo dos Santos Sousa

This work proposes a Bayesian rule based on the mixture of a point mass function at zero and the logistic distribution to perform wavelet shrinkage in nonparametric regression models with stationary errors (with short or long-memory…

Methodology · Statistics 2024-04-24 Alex Rodrigo dos S. Sousa , Mauricio Zevallos

Consider the univariate nonparametric regression model with additive Gaussian noise and the representation of the unknown regression function in terms of a wavelet basis. We propose a shrinkage rule to estimate the wavelet coefficients…

Methodology · Statistics 2025-07-17 Fidel Aniano Causil Barrios , Alex Rodrigo dos Santos Sousa

We propose a Bayesian shrinkage rule to estimate the wavelet coefficients in a nonparametric regression model with Gaussian errors, based on a mixture of a point mass function at zero and a symmetric, zero-centered raised cosine…

Methodology · Statistics 2025-07-16 Juliana Marchesi Reina , Alex Rodrigo dos Santos Sousa

This work proposes a wavelet shrinkage rule under asymmetric LINEX loss function and a mixture of a point mass function at zero and the logistic distribution as prior distribution to the wavelet coefficients in a nonparametric regression…

Methodology · Statistics 2023-07-27 Alex Rodrigo dos Santos Sousa

In bayesian wavelet shrinkage, the already proposed priors to wavelet coefficients are assumed to be symmetric around zero. Although this assumption is reasonable in many applications, it is not general. The present paper proposes the use…

Methodology · Statistics 2020-10-12 Alex Rodrigo dos Santos Sousa

We propose a Bayesian method to detect change points for functional data. We extract the features of a sequence of functional data by the discrete wavelet transform (DWT), and treat each sequence of feature independently. We believe there…

Methodology · Statistics 2018-08-06 Xiuqi Li , Subhashis Ghosal

In the frame of the traditional wavelet-Galerkin method based on the compactly supported wavelets, it is important to calculate the so-called connection coefficients that are some integrals whose integrands involve products of wavelets,…

Numerical Analysis · Mathematics 2018-01-25 Zhaochen Yang , Shijun Liao

Image data are increasingly encountered and are of growing importance in many areas of science. Much of these data are quantitative image data, which are characterized by intensities that represent some measurement of interest in the…

In this paper we propose a shrinkage wavelet-based method to estimate the signal in a nonparametric regression model with Autoregressive Fractionally Integrated Moving Average (ARFIMA) errors. Monte Carlo experiments indicate that the…

Methodology · Statistics 2025-05-13 Alex Rodrigo dos S. Sousa , Mauricio Zevallos

Functional data consist of trajectories observed over a continuous domain, such as time, space, or wavelength. Here we consider curves observed on different groups of subjects and propose a Bayesian multi-group functional factor analysis…

Methodology · Statistics 2026-04-02 Xuanye Dai , Anna Gottard , Michele Guindani , Marina Vannucci

Functional data analysis deals with data recorded densely over time (or any other continuum) with one or more observed curves per subject. Conceptually, functional data are continuously defined, but in practice, they are usually observed at…

Methodology · Statistics 2023-01-20 Chengqian Xian , Camila de Souza , John Jewell , Ronaldo Dias

This paper proposes a class of asymmetric priors to perform Bayesian wavelet shrinkage in the standard nonparametric regression model with Gaussian error. The priors are composed by mixtures of a point mass function at zero and one of the…

Methodology · Statistics 2024-10-03 Alex Rodrigo dos Santos Sousa

Wavelet shrinkage estimators are widely applied in several fields of science for denoising data in wavelet domain by reducing the magnitudes of empirical coefficients. In nonparametric regression problem, most of the shrinkage rules are…

Methodology · Statistics 2021-09-14 Alex Rodrigo dos Santos Sousa , Nancy Lopes Garcia

Functional data analysis almost always involves smoothing discrete observations into curves, because they are never observed in continuous time and rarely without error. Although smoothing parameters affect the subsequent inference,…

Methodology · Statistics 2025-04-07 Sunny G. W. Wang , Valentin Patilea , Nicolas Klutchnikoff

In wavelet shrinkage and thresholding, most of the standard techniques do not consider information that wavelet coefficients might be bounded, although information about bounded energy in signals can be readily available. To address this,…

Methodology · Statistics 2020-11-12 Alex Rodrigo dos Santos Sousa , Nancy Lopes Garcia , Branislav Vidakovic

In many areas of science one aims to estimate latent sub-population mean curves based only on observations of aggregated population curves. By aggregated curves we mean linear combination of functional data that cannot be observed…

Methodology · Statistics 2011-02-15 Ronaldo Dias , Nancy L. Garcia , Alexandra M. Schmidt

We introduce a new method of Bayesian wavelet shrinkage for reconstructing a signal when we observe a noisy version. Rather than making the common assumption that the wavelet coefficients of the signal are independent, we allow for the…

Methodology · Statistics 2009-03-17 Graeme K. Ambler , Bernard W. Silverman

Motivated by distinct walking patterns in real-world free-living gait data, this paper proposes an innovative curve-based sampling scheme for the analysis of functional data characterized by a mixture of covariance structures. Traditional…

Methodology · Statistics 2025-04-10 Yian Yu , Bo Wang , Jian Qing Shi
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