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In space-time adaptive processing (STAP) of the airborne radar system, it is very important to realize sparse restoration of the clutter covariance matrix with a small number of samples. In this paper, a clutter suppression method for…

Signal Processing · Electrical Eng. & Systems 2023-01-30 Tao Zhang , Haifang Zheng , Qijun Luo

This paper considers the estimation and inference of the low-rank components in high-dimensional matrix-variate factor models, where each dimension of the matrix-variates ($p \times q$) is comparable to or greater than the number of…

Statistics Theory · Mathematics 2022-10-20 Elynn Y. Chen , Jianqing Fan

Low-Rank Adaptation (LoRA) is a widely adopted parameter-efficient fine-tuning (PEFT) method validated across NLP and CV domains. However, LoRA faces an inherent low-rank bottleneck: narrowing its performance gap with full finetuning…

Machine Learning · Computer Science 2025-12-03 Haonan Dong , Wenhao Zhu , Guojie Song , Liang Wang

In this paper, we investigate the problem of jointly optimizing the waveform covariance matrix and the antenna position vector for multiple-input-multiple-output (MIMO) radar systems to approximate a desired transmit beampattern as well as…

Signal Processing · Electrical Eng. & Systems 2019-12-03 Arindam Bose , Shahin Khobahi , Mojtaba Soltanalian

Linear and Quadratic Discriminant analysis (LDA/QDA) are common tools for classification problems. For these methods we assume observations are normally distributed within group. We estimate a mean and covariance matrix for each group and…

Machine Learning · Statistics 2011-12-08 Noah Simon , Rob Tibshirani

Contemporary wireless communication systems rely on Multi-User Multiple-Input Multiple-Output (MU-MIMO) techniques. In such systems, each Access Point (AP) is equipped with multiple antenna elements and serves multiple devices…

Information Theory · Computer Science 2024-12-24 Eduardo Noboro Tominaga , Onel Luis Alcaraz López , Tommy Svensson , Richard Demo Souza , Hirley Alves

Sparse covariance matrices play crucial roles by encoding the interdependencies between variables in numerous fields such as genetics and neuroscience. Despite substantial studies on sparse covariance matrices, existing methods face several…

Methodology · Statistics 2026-03-03 Rakheon Kim , Irina Gaynanova

We propose a novel algorithm to estimate the channel covariance matrix of a desired user in multiuser massive MIMO systems. The algorithm uses only knowledge of the array response and rough knowledge of the angular support of the incoming…

Signal Processing · Electrical Eng. & Systems 2020-06-15 Renato Luis Garrido Cavalcante , Slawomir Stanczak

In this work, we propose an alternating low-rank decomposition (ALRD) approach and novel subspace algorithms for direction-of-arrival (DOA) estimation. In the ALRD scheme, the decomposition matrix for rank reduction is composed of a set of…

Information Theory · Computer Science 2016-04-18 Yunlong Cai , Linzheng Qiu , Rodrigo C. de Lamare , Minjian Zhao

We propose a general procedure for estimating the variance-covariance matrix of two-step estimates of structural parameters in latent variable models. The method is partially simulation-based, in that it includes drawing simulated values of…

Methodology · Statistics 2025-07-23 Roberto Di Mari , Jouni Kuha

This paper tackles the problem of robust covariance matrix estimation when the data is incomplete. Classical statistical estimation methodologies are usually built upon the Gaussian assumption, whereas existing robust estimation ones assume…

Exponential growth in the scale of modern foundation models has led to the widespread adoption of Low-Rank Adaptation (LoRA) as a parameter-efficient fine-tuning technique. However, standard LoRA implementations disregard the varying…

Artificial Intelligence · Computer Science 2026-05-01 Vishnuprasadh Kumaravelu , Sunil Gupta , P. K. Srijith

Controlling the radar beam-pattern by optimizing the transmit covariance matrix is a well-established approach for performance enhancement in multiple-input-multiple-output (MIMO) radars. In this paper, we investigate the joint optimization…

Signal Processing · Electrical Eng. & Systems 2022-08-10 Arindam Bose , Shahin Khobahi , Mojtaba Soltanalian

We propose a method for estimating a covariance matrix that can be represented as a sum of a low-rank matrix and a diagonal matrix. The proposed method compresses high-dimensional data, computes the sample covariance in the compressed…

Methodology · Statistics 2017-04-04 Gautam Sabnis , Debdeep Pati , Anirban Bhattacharya

Extremely large-scale antenna array (ELAA) systems emerge as a promising technology in beyond 5G and 6G wireless networks to support the deployment of distributed architectures. This paper explores the use of ELAAs to enable joint…

We consider the problem of joint estimation of structured inverse covariance matrices. We perform the estimation using groups of measurements with different covariances of the same unknown structure. Assuming the inverse covariances to span…

Machine Learning · Statistics 2015-11-23 Ilya Soloveychik , Ami Wiesel

Relying on recent advances in statistical estimation of covariance distances based on random matrix theory, this article proposes an improved covariance and precision matrix estimation for a wide family of metrics. The method is shown to…

Machine Learning · Statistics 2021-02-03 Malik Tiomoko , Florent Bouchard , Guillaume Ginholac , Romain Couillet

Many data-analysis problems involve large dense matrices that describe the covariance of stationary noise processes; the computational cost of inverting these matrices, or equivalently of solving linear systems that contain them, is often a…

Instrumentation and Methods for Astrophysics · Physics 2015-06-22 Rutger van Haasteren , Michele Vallisneri

We propose a novel pilot structure for covariance matrix estimation in massive multiple-input multiple-output (MIMO) systems in which each user transmits two pilot sequences, with the second pilot sequence multiplied by a random…

Information Theory · Computer Science 2018-04-04 Karthik Upadhya , Sergiy A. Vorobyov

This paper proposes a novel localization framework underpinned by a pinching-antenna (PA) system, in which the target location is estimated using received signal strength (RSS) measurements obtained from downlink signals transmitted by the…

Signal Processing · Electrical Eng. & Systems 2025-11-20 Jiajun He , Xidong Mu , Hien Quoc Ngo , Michail Matthaiou