533 research outputs found
A Bayesian Approach for Noisy Matrix Completion: Optimal Rate under General Sampling Distribution
Bayesian methods for low-rank matrix completion with noise have been shown to
be very efficient computationally. While the behaviour of penalized
minimization methods is well understood both from the theoretical and
computational points of view in this problem, the theoretical optimality of
Bayesian estimators have not been explored yet. In this paper, we propose a
Bayesian estimator for matrix completion under general sampling distribution.
We also provide an oracle inequality for this estimator. This inequality proves
that, whatever the rank of the matrix to be estimated, our estimator reaches
the minimax-optimal rate of convergence (up to a logarithmic factor). We end
the paper with a short simulation study
A reduced-rank approach to predicting multiple binary responses through machine learning
This paper investigates the problem of simultaneously predicting multiple
binary responses by utilizing a shared set of covariates. Our approach
incorporates machine learning techniques for binary classification, without
making assumptions about the underlying observations. Instead, our focus lies
on a group of predictors, aiming to identify the one that minimizes prediction
error. Unlike previous studies that primarily address estimation error, we
directly analyze the prediction error of our method using PAC-Bayesian bounds
techniques. In this paper, we introduce a pseudo-Bayesian approach capable of
handling incomplete response data. Our strategy is efficiently implemented
using the Langevin Monte Carlo method. Through simulation studies and a
practical application using real data, we demonstrate the effectiveness of our
proposed method, producing comparable or sometimes superior results compared to
the current state-of-the-art method
Numerical comparisons between Bayesian and frequentist low-rank matrix completion: estimation accuracy and uncertainty quantification
In this paper we perform a numerious numerical studies for the problem of
low-rank matrix completion. We compare the Bayesain approaches and a recently
introduced de-biased estimator which provides a useful way to build confidence
intervals of interest. From a theoretical viewpoint, the de-biased estimator
comes with a sharp minimax-optinmal rate of estimation error whereas the
Bayesian approach reaches this rate with an additional logarithmic factor. Our
simulation studies show originally interesting results that the de-biased
estimator is just as good as the Bayesain estimators. Moreover, Bayesian
approaches are much more stable and can outperform the de-biased estimator in
the case of small samples. However, we also find that the length of the
confidence intervals revealed by the de-biased estimator for an entry is
absolutely shorter than the length of the considered credible interval. These
suggest further theoretical studies on the estimation error and the
concentration for Bayesian methods as they are being quite limited up to
present
On a low-rank matrix single index model
In this paper, we present a theoretical study of a low-rank matrix single
index model. This model is recently introduced in biostatistics however its
theoretical properties on estimating together the link function and the
coefficient matrix are not yet carried out. Here, we advance on using
PAC-Bayesian bounds technique to provide a rigorous theoretical understanding
for jointly estimation of the link function and the coefficient matrix
From bilinear regression to inductive matrix completion: a quasi-Bayesian analysis
In this paper we study the problem of bilinear regression and we further
address the case when the response matrix contains missing data that referred
as the problem of inductive matrix completion. We propose a quasi-Bayesian
approach first to the problem of bilinear regression where a quasi-likelihood
is employed. Then, we adapt this approach to the context of inductive matrix
completion. Under a low-rankness assumption and leveraging PAC-Bayes bound
technique, we provide statistical properties for our proposed estimators and
for the quasi-posteriors. We propose a Langevin Monte Carlo method to
approximately compute the proposed estimators. Some numerical studies are
conducted to demonstrated our methods.Comment: arXiv admin note: substantial text overlap with arXiv:2206.0861
Simulation study on the influence of a dielectric constant gradient in the concrete on the direct wave of GPR measurements
Ground Penetrating Radar (GPR) is a non-destructive technique based on the propagation of electromagnetic wave, the propagation characteristics (speed, level of signal attenuation, ...) depend on the electromagnetic properties of the material through which it passes, where the dielectric constant of the material is one of the key parameters. Previous studies mainly based on the analysis of reflected signals to evaluate the transmission medium. Recently, the research to exploit the application of GPR direct wave (wave propagate directly in the material from the transmitting antenna to the receiving antenna) for characterization of the structural materials is becoming a matter of great interest.This paper focuses on studying on the influence of a gradient of dielectric constant in concrete on GPR direct wave, and at the same time evaluates the survey depth of GPR direct wave in concrete materials. The studying was carried out by simulation method based on GPRmax - 2D software fortwo concrete models with two gradients of dielectric constant and simultaneously with two antennas with center frequencies of 1.5 GHz and 2.6 GHz, respectively.Analysis of the obtained simulation results allows to evaluate the influence of the dielectric constant gradient on the GPR direct wave and the survey depth of the GPR direct wave.
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