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The dependency structure of multivariate data can be analyzed using the covariance matrix $\Sigma$. In many fields the precision matrix $\Sigma^{-1}$ is even more informative. As the sample covariance estimator is singular in…

Methodology · Statistics 2015-06-04 Viktoria Öllerer , Christophe Croux

In single-particle cryo-electron microscopy (cryo-EM), the efficient determination of orientation parameters for 2D projection images poses a significant challenge yet is crucial for reconstructing 3D structures. This task is complicated by…

Image and Video Processing · Electrical Eng. & Systems 2025-09-30 Szu-Chi Chung

Cryogenic electron microscopy is widely used in structural biology, but its resolution is often limited by the dynamics of the macromolecule. Here, we developed a refinement protocol based on Gaussian mixture models that integrates particle…

Quantitative Methods · Quantitative Biology 2023-08-31 Muyuan Chen , Michael F. Schmid , Wah Chiu

The estimation of covariance matrices of gene expressions has many applications in cancer systems biology. Many gene expression studies, however, are hampered by low sample size and it has therefore become popular to increase sample size by…

Motivation: Assessing the match between two biomolecular structures is at the heart of structural analyses such as superposition, alignment and docking. These tasks are typically solved with specialized structure-matching techniques…

Biomolecules · Quantitative Biology 2024-01-23 Michael Habeck , Andreas Kröpelin , Nima Vakili

This paper focuses on the estimation of the sample covariance matrix from low-dimensional random projections of data known as compressive measurements. In particular, we present an unbiased estimator to extract the covariance structure from…

Machine Learning · Statistics 2017-05-01 Farhad Pourkamali-Anaraki

There is a clear need for developments in characterisation techniques that provide detailed information about structure-function relationships in biology. Using electron microscopy to achieve high resolution while maintaining a broad field…

Quantitative Methods · Quantitative Biology 2023-09-12 Chen Huang , Judy S. Kim , Angus I. Kirkland

Differentiating signals from the background in micrographs is a critical initial step for cryogenic electron microscopy (cryo-EM), yet it remains laborious due to low signal-to-noise ratio (SNR), the presence of contaminants and densely…

Image and Video Processing · Electrical Eng. & Systems 2025-09-30 Szu-Chi Chung , Po-Cheng Chou

Accurately predicting enzyme functionality remains one of the major challenges in computational biology, particularly for enzymes with limited structural annotations or sequence homology. We present a novel multimodal Quantum Machine…

Machine Learning · Computer Science 2025-08-21 Murat Isik , Mandeep Kaur Saggi , Humaira Gowher , Sabre Kais

A hierarchical Bayesian approach that permits simultaneous inference for the regression coefficient matrix and the error precision (inverse covariance) matrix in the multivariate linear model is proposed. Assuming a natural ordering of the…

Methodology · Statistics 2024-10-29 Christina Zhao , Ding Xiang , Galin L. Jones , Adam J. Rothman

In this self-contained chapter, we revisit a fundamental problem of multivariate statistics: estimating covariance matrices from finitely many independent samples. Based on massive Multiple-Input Multiple-Output (MIMO) systems we illustrate…

Statistics Theory · Mathematics 2021-06-14 Johannes Maly , Tianyu Yang , Sjoerd Dirksen , Holger Rauhut , Giuseppe Caire

We propose a flexible Bayesian approach for estimating the joint density of a multivariate outcome of interest in the presence of categorical covariates. Leveraging a Gaussian copula framework, our method effectively captures the dependence…

Methodology · Statistics 2026-04-10 Giovanni Toto , Peter Müller , Abhra Sarkar

In practice, observations are often contaminated by noise, making the resulting sample covariance matrix to be an information-plus-noise-type covariance matrix. Aiming to make inferences about the spectra of the underlying true covariance…

Statistics Theory · Mathematics 2015-08-25 Ningning Xia , Xinghua Zheng

This paper tackles the problem of jointly estimating the noise covariance matrix alongside states (parameters such as poses and points) from measurements corrupted by Gaussian noise and, if available, prior information. In such settings,…

Robotics · Computer Science 2025-08-13 Kasra Khosoussi , Iman Shames

Electron Cryo-Tomography (ECT) enables 3D visualization of macromolecule structure inside single cells. Macromolecule classification approaches based on convolutional neural networks (CNN) were developed to separate millions of…

Quantitative Methods · Quantitative Biology 2018-03-28 Jialiang Guo , Bo Zhou , Xiangrui Zeng , Zachary Freyberg , Min Xu

Cryo-electron tomography (cryo-ET) enables structural characterization of biomolecules under near-native conditions. Existing approaches for interpreting the resulting three-dimensional volumes are computationally expensive and have…

Quantitative Methods · Quantitative Biology 2025-10-28 Chengxuan Li , August George , Reece Neff , Doo Nam Kim , Trevor Moser , Kate Baldwin , Malio Nelson , Arsam Firoozfar , James E Evans , Margaret S Cheung

We consider the problem of estimating a high-dimensional covariance matrix from a small number of observations when covariates on pairs of variables are available and the variables can have spatial structure. This is motivated by the…

This dissertation explores how deep generative models can advance the analysis of challenging biological problems by integrating domain knowledge with deep learning. It focuses on two areas: DNA reaction kinetics and cryogenic electron…

Machine Learning · Computer Science 2026-05-07 Chenwei Zhang

Computer Vision practitioners must thoroughly understand their model's performance, but conditional evaluation is complex and error-prone. In biometric verification, model performance over continuous covariates---real-number attributes of…

Machine Learning · Computer Science 2020-09-22 Mel McCurrie , Hamish Nicholson , Walter J. Scheirer , Samuel Anthony

In single particle reconstruction (SPR) from cryo-electron microscopy (cryo-EM), the 3D structure of a molecule needs to be determined from its 2D projection images taken at unknown viewing directions. Zvi Kam showed already in 1980 that…

Computer Vision and Pattern Recognition · Computer Science 2016-02-24 Tejal Bhamre , Teng Zhang , Amit Singer