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This paper deals with the time-varying high dimensional covariance matrix estimation. We propose two covariance matrix estimators corresponding with a time-varying approximate factor model and a time-varying approximate characteristic-based…

Econometrics · Economics 2019-10-29 Jaeheon Jung

The variance--covariance matrix plays a central role in the inferential theories of high-dimensional factor models in finance and economics. Popular regularization methods of directly exploiting sparsity are not directly applicable to many…

Methodology · Statistics 2012-03-15 Jianqing Fan , Yuan Liao , Martina Mincheva

Existing fine-tuning methods either tune all parameters of the pre-trained model (full fine-tuning), which is not efficient, or only tune the last linear layer (linear probing), which suffers a significant accuracy drop compared to the full…

Computer Vision and Pattern Recognition · Computer Science 2023-01-18 Dongze Lian , Daquan Zhou , Jiashi Feng , Xinchao Wang

We revisit the widely used bss eval metrics for source separation with an eye out for performance. We propose a fast algorithm fixing shortcomings of publicly available implementations. First, we show that the metrics are fully specified by…

Audio and Speech Processing · Electrical Eng. & Systems 2021-10-14 Robin Scheibler

Nowadays, it is possible to scan faces and automatically register them with high quality. However, the resulting face meshes often need further processing: we need to stabilize them to remove unwanted head movement. Stabilization is…

Computer Vision and Pattern Recognition · Computer Science 2024-11-25 Jan Bednarik , Erroll Wood , Vasileios Choutas , Timo Bolkart , Daoye Wang , Chenglei Wu , Thabo Beeler

We provide a MATLAB toolbox, BFDA, that implements a Bayesian hierarchical model to smooth multiple functional data with the assumptions of the same underlying Gaussian process distribution, a Gaussian process prior for the mean function,…

Other Statistics · Statistics 2017-02-06 Jingjing Yang , Peng Ren

Face detection and alignment in unconstrained environment are challenging due to various poses, illuminations and occlusions. Recent studies show that deep learning approaches can achieve impressive performance on these two tasks. In this…

Computer Vision and Pattern Recognition · Computer Science 2016-09-21 Kaipeng Zhang , Zhanpeng Zhang , Zhifeng Li , Yu Qiao

Scale-invariance, good localization and robustness to noise and distortions are the main properties that a local feature detector should possess. Most existing local feature detectors find excessive unstable feature points that increase the…

Computer Vision and Pattern Recognition · Computer Science 2021-02-03 Morteza Ghahremani , Yonghuai Liu , Bernard Tiddeman

We derive high-dimensional scaling limits and fluctuations for the online least-squares Stochastic Gradient Descent (SGD) algorithm by taking the properties of the data generating model explicitly into consideration. Our approach treats the…

Probability · Mathematics 2024-04-05 Krishnakumar Balasubramanian , Promit Ghosal , Ye He

Computing power has evolved into a foundational and indispensable resource in the area of deep learning, particularly in tasks such as Face Recognition (FR) model training on large-scale datasets, where multiple GPUs are often a necessity.…

Computer Vision and Pattern Recognition · Computer Science 2024-12-12 Xueyuan Gong , Zhiquan Liu , Yain-Whar Si , Xiaochen Yuan , Ke Wang , Xiaoxiang Liu , Cong Lin , Xinyuan Zhang

Human face images usually appear with wide range of visual scales. The existing face representations pursue the bandwidth of handling scale variation via multi-scale scheme that assembles a finite series of predefined scales. Such…

Computer Vision and Pattern Recognition · Computer Science 2022-09-20 Hailin Shi , Hang Du , Yibo Hu , Jun Wang , Dan Zeng , Ting Yao

In some applications, one is interested in reconstructing a function $f$ from its Fourier series coefficients. The problem is that the Fourier series is slowly convergent if the function is non-periodic, or is non-smooth. In this paper, we…

Numerical Analysis · Mathematics 2020-04-14 David Levin

Recent studies have demonstrated improved skill in numerical weather prediction via the use of spatially correlated observation error covariance information in data assimilation systems. In this case, the observation weighting matrices…

Numerical Analysis · Mathematics 2022-01-05 Guannan Hu , Sarah L. Dance

Visual saliency is a fundamental problem in both cognitive and computational sciences, including computer vision. In this CVPR 2015 paper, we discover that a high-quality visual saliency model can be trained with multiscale features…

Computer Vision and Pattern Recognition · Computer Science 2015-04-13 Guanbin Li , Yizhou Yu

Estimating and storing the covariance (or correlation) matrix of high-dimensional data is computationally challenging because both memory and computational requirements scale quadratically with the dimension. Fortunately, high-dimensional…

Data Structures and Algorithms · Computer Science 2021-06-14 Zhenwei Dai , Aditya Desai , Reinhard Heckel , Anshumali Shrivastava

This paper addresses the fundamental task of estimating covariance matrix functions for high-dimensional functional data/functional time series. We consider two functional factor structures encompassing either functional factors with scalar…

Methodology · Statistics 2025-10-28 Dong Li , Xinghao Qiao , Zihan Wang

Wearable devices permit the continuous monitoring of biological processes, such as blood glucose metabolism, and behavior, such as sleep quality and physical activity. The continuous monitoring often occurs in epochs of 60 seconds over…

Methodology · Statistics 2024-04-23 Yuanyuan Luan , Roger S. Zoh , Erjia Cui , Xue Lan , Sneha Jadhav , Carmen D. Tekwe

Slow feature analysis (SFA) is a method for extracting slowly varying features from a quickly varying multidimensional signal. An open source Matlab-implementation sfa-tk makes SFA easily useable. We show here that under certain…

Machine Learning · Statistics 2009-12-08 Wolfgang Konen

Inference and simulation in the context of high-dimensional dynamical systems remain computationally challenging problems. Some form of dimensionality reduction is required to make the problem tractable in general. In this paper, we propose…

Machine Learning · Statistics 2024-01-04 Jonathan Schmidt , Philipp Hennig , Jörg Nick , Filip Tronarp

This article introduces a functional method for lower-dimensional smooth representations in terms of time-varying dissimilarities. The method incorporates dissimilarity representation in multidimensional scaling and smoothness approach of…

Methodology · Statistics 2025-05-02 Liting Li