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A separable covariance model for a random matrix provides a parsimonious description of the covariances among the rows and among the columns of the matrix, and permits likelihood-based inference with a very small sample size. However, in…

Methodology · Statistics 2022-07-27 Peter Hoff , Andrew McCormack , Anru R. Zhang

We provide a unified approach to a method of estimation of the regression parameter in balanced linear models with a structured covariance matrix that combines a high breakdown point and bounded influence with high asymptotic efficiency at…

Statistics Theory · Mathematics 2023-03-22 Hendrik Paul Lopuhaä

The accurate classification of brain tumors from MRI scans is essential for effective diagnosis and treatment planning. This paper presents a weighted ensemble learning approach that combines deep learning and traditional machine learning…

Computer Vision and Pattern Recognition · Computer Science 2026-03-31 Ha Anh Vu

We introduce a statistical procedure that integrates survival data from multiple biomedical studies, to improve the accuracy of predictions of survival or other events, based on individual clinical and genomic profiles, compared to models…

Applications · Statistics 2020-07-20 Steffen Ventz , Rahul Mazumder , Lorenzo Trippa

In this paper we investigate the performance of periodogram based estimators of the spectral density matrix of possibly high-dimensional time series. We suggest and study shrinkage as a remedy against numerical instabilities due to…

Statistics Theory · Mathematics 2008-08-13 Hilmar Böhm , Rainer von Sachs

Early detection is crucial for successful cancer treatment and increasing survivability rates, particularly in the most common forms. Ten different cancers have been identified in most of these advances that effectively use CNNs…

Computer Vision and Pattern Recognition · Computer Science 2026-05-15 Hossein Molaeian , Kaveh Karamjani , Sina Teimouri , Saeed Roshani , Sobhan Roshani

While covariance matrices have been widely studied in many scientific fields, relatively limited progress has been made on estimating conditional covariances that permits a large covariance matrix to vary with high-dimensional subject-level…

Methodology · Statistics 2025-05-28 Rakheon Kim , Jingfei Zhang

We propose a model to forecast large realized covariance matrices of returns, applying it to the constituents of the S\&P 500 daily. To address the curse of dimensionality, we decompose the return covariance matrix using standard firm-level…

Statistical Finance · Quantitative Finance 2023-03-29 Rafael Alves , Diego S. de Brito , Marcelo C. Medeiros , Ruy M. Ribeiro

Linear model prediction with a large number of potential predictors is both statistically and computationally challenging. The traditional approaches are largely based on shrinkage selection/estimation methods, which are applicable even…

Methodology · Statistics 2024-09-17 Hanmei Sun , Jiangshan Zhang , Jiming Jiang

This paper considers the problem of robustly estimating a structured covariance matrix with an elliptical underlying distribution with known mean. In applications where the covariance matrix naturally possesses a certain structure, taking…

Applications · Statistics 2016-06-29 Ying Sun , Prabhu Babu , Daniel P. Palomar

We propose to estimate the weight matrix used for forecast reconciliation as parameters in a general linear model in order to quantify its uncertainty. This implies that forecast reconciliation can be formulated as an orthogonal projection…

Methodology · Statistics 2024-02-12 Jan Kloppenborg Møller , Peter Nystrup , Poul G. Hjorth , Henrik Madsen

We consider the problem of joint estimation of structured covariance matrices. Assuming the structure is unknown, estimation is achieved using heterogeneous training sets. Namely, given groups of measurements coming from centered…

Statistics Theory · Mathematics 2016-04-20 Ilya Soloveychik , Ami Wiesel

VARs are often estimated with Bayesian techniques to cope with model dimensionality. The posterior means define a class of shrinkage estimators, indexed by hyperparameters that determine the relative weight on maximum likelihood estimates…

Econometrics · Economics 2025-02-07 Oriol González-Casasús , Frank Schorfheide

Personalized treatment of patients based on tissue-specific cancer subtypes has strongly increased the efficacy of the chosen therapies. Even though the amount of data measured for cancer patients has increased over the last years, most…

Machine Learning · Statistics 2017-09-18 Nora K. Speicher , Nico Pfeifer

We provide a unified approach to MM-estimation with auxiliary scale for balanced linear models with structured covariance matrices. This approach leads to estimators that are highly robust against outliers and highly efficient for normal…

Statistics Theory · Mathematics 2025-11-10 Hendrik Paul Lopuhaa

Network-based analyses of high-throughput genomics data provide a holistic, systems-level understanding of various biological mechanisms for a common population. However, when estimating multiple networks across heterogeneous…

We propose a novel variational Bayes approach to estimate high-dimensional vector autoregression (VAR) models with hierarchical shrinkage priors. Our approach does not rely on a conventional structural VAR representation of the parameter…

Econometrics · Economics 2023-07-03 Mauro Bernardi , Daniele Bianchi , Nicolas Bianco

We consider the problem of estimating multiple related but distinct graphical models on the basis of a high-dimensional data set with observations that belong to distinct classes. A motivating example occurs in the analysis of gene…

Methodology · Statistics 2012-07-12 Patrick Danaher , Pei Wang , Daniela M. Witten

In many applications (e.g., medical studies), the population of interest (e.g., disease status) comprises heterogeneous subpopulations. The mixture of probabilistic regression models is one of the most common techniques to incorporate the…

Methodology · Statistics 2022-09-13 Elsayed Ghanem , Armin Hatefi , Hamid Usefi

We study ridge estimation of the precision matrix in the high-dimensional setting where the number of variables is large relative to the sample size. We first review two archetypal ridge estimators and note that their utilized penalties do…

Methodology · Statistics 2016-06-17 Wessel N. van Wieringen , Carel F. W. Peeters