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A large-scale fully-digital receive antenna array can provide very high-resolution direction of arrival (DOA) estimation, but resulting in a significantly high RF-chain circuit cost. Thus, a hybrid analog and digital (HAD) structure is…

Information Theory · Computer Science 2017-12-07 Feng Shu , Yaolu Qin , Tingting Liu , Linqing Gui , Yijin Zhang , Jun Li , Zhu Han

In this paper, we propose a new stochastic alternating direction method of multipliers (ADMM) algorithm, which incrementally approximates the full gradient in the linearized ADMM formulation. Besides having a low per-iteration complexity as…

Machine Learning · Computer Science 2013-08-19 Leon Wenliang Zhong , James T. Kwok

In this paper, we propose a faster stochastic alternating direction method of multipliers (ADMM) for nonconvex optimization by using a new stochastic path-integrated differential estimator (SPIDER), called as SPIDER-ADMM. Moreover, we prove…

Optimization and Control · Mathematics 2020-08-12 Feihu Huang , Songcan Chen , Heng Huang

Radio Interferometry is an essential method for astronomical observations. Self-calibration techniques have increased the quality of the radio astronomical observations (and hence the science) by orders of magnitude. Recently, there is a…

Astrophysics · Physics 2008-11-03 Sarod Yatawatta , Saleem Zaroubi , Ger de Bruyn , Leon Koopmans , Jan Noordam

In this paper, a compact alternating direction implicit (ADI) method has been developed for solving two-dimensional Riesz space fractional diffusion equation. The precision of the discretization method used in spatial directions is twice…

Numerical Analysis · Mathematics 2020-04-21 Sohrab Valizadeh , Alaeddin Malek , Abdollah Borhanifar

Efficient and accurate numerical simulation of seismic wave propagation is important in various Geophysical applications such as seismic full waveform inversion (FWI) problem. However, due to the large size of the physical domain and…

Numerical Analysis · Computer Science 2019-03-22 Keran Li , Wenyuan Liao , Yaoting Lin

Modern adaptive optimization methods, such as Adam and its variants, have emerged as the most widely used tools in deep learning over recent years. These algorithms offer automatic mechanisms for dynamically adjusting the update step based…

Machine Learning · Computer Science 2025-02-12 Son Nguyen , Bo Liu , Lizhang Chen , Qiang Liu

Radio interferometers are phased arrays producing high-resolution images from the covariance matrix of measurements. Calibration of such instruments is necessary and is a critical task. This is how the estimation of instrumental errors is…

Instrumentation and Methods for Astrophysics · Physics 2023-09-26 Yassine Mhiri , Mohammed Nabil El Korso , Arnaud Breloy , Pascal Larzabal

Hybrid analog-digital beamforming stands out as a key enabler for future communication systems with a massive number of antennas. In this paper, we investigate the hybrid precoder design problem for angle-of-departure (AoD) estimation,…

Information Theory · Computer Science 2024-10-24 Huiping Huang , Musa Furkan Keskin , Henk Wymeersch , Xuesong Cai , Linlong Wu , Johan Thunberg , Fredrik Tufvesson

Continuous-time algebraic Lyapunov equations have become an essential tool in various applications. In the case of large-scale sparse coefficient matrices and indefinite constant terms, indefinite low-rank factorizations have successfully…

Numerical Analysis · Mathematics 2025-12-05 Rudi Smith , Steffen W. R. Werner

This paper introduces a backpropagation-based technique for the calibration of the mismatch errors of time-interleaved analog to digital converters (TI-ADCs). This technique is applicable to digital receivers such as those used in coherent…

Signal Processing · Electrical Eng. & Systems 2020-08-10 Fredy Solis , Benjamín T. Reyes , Damián A. Morero , Mario R. Hueda

The Peaceman-Rachford alternating direction implicit (ADI) scheme for linear time-dependent Maxwell equations is analyzed on a heterogeneous cuboid. Due to discontinuities of the material parameters, the solution of the Maxwell equations is…

Numerical Analysis · Mathematics 2022-12-29 Konstantin Zerulla , Tobias Jahnke

In this work, we consider the problem of joint calibration and direction-of-arrival (DOA) estimation using sensor arrays. This joint estimation problem is referred to as self calibration. Unlike many previous iterative approaches, we…

Signal Processing · Electrical Eng. & Systems 2021-04-07 Krishnaprasad Nambur Ramamohan , Sundeep Prabhakar Chepuri , Daniel Fernandez Comesana , Geert Leus

This paper considers large-scale nonsymmetric continuous-time algebraic Riccati equations (NAREs) that admit low-rank solutions. Low-rank alternating direction implicit (ADI) methods have proven to be an efficient approach for solving…

Numerical Analysis · Mathematics 2026-04-28 Umair Zulfiqar

Massive multiple-input multiple-output (MIMO) radar, enabled by millimeter-wave virtual MIMO techniques, provides great promises to the high-resolution automotive sensing and target detection in unmanned ground/aerial vehicles (UGA/UAV). As…

Signal Processing · Electrical Eng. & Systems 2021-12-22 Bin Li , Shuseng Wang , Jun Zhang , Xainbin Cao , Chenglin Zhao

In this work, we study two-dimensional diffusion-wave equations with variable exponent, modeling mechanical diffusive wave propagation in viscoelastic media with spatially varying properties. We first transform the diffusion-wave model into…

Numerical Analysis · Mathematics 2025-09-26 Hao Zhang , Kexin Li , Wenlin Qiu

This paper investigates calibration of sensor arrays in the radio astronomy context. Current and future radio telescopes require computationally efficient algorithms to overcome the new technical challenges as large collecting area, wide…

Applications · Statistics 2018-07-31 Virginie Ollier , Mohammed Nabil El Korso , André Ferrari , Rémy Boyer , Pascal Larzabal

Distinguishing signal of young gas rich circumstellar disks from stellar signal in near infrared light is a difficult task. Current techniques such as Angular Differential Imaging (ADI) and Polarimetric Differential Imaging (PDI) cope with…

Instrumentation and Methods for Astrophysics · Physics 2022-12-07 L. M. Stapper , C. Ginski

In millimeter-wave channels, most of the received energy is carried by a few paths. Traditional precoders sweep the angle-of-departure (AoD) and angle-of-arrival (AoA) space with directional precoders to identify directions with largest…

Information Theory · Computer Science 2018-11-14 Nil Garcia , Henk Wymeersch , Dirk Slock

The low-rank alternating direction implicit (ADI) method is an efficient and effective solver for large-scale standard continuous-time algebraic Riccati equations that admit low-rank solutions. However, the existing low-rank ADI algorithm…

Numerical Analysis · Mathematics 2026-04-16 Umair Zulfiqar