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This paper investigates the problem of signal estimation from undersampled noisy sub-Gaussian measurements under the assumption of a cosparse model. Based on generalized notions of sparsity, we derive novel recovery guarantees for the…

Information Theory · Computer Science 2021-02-23 Martin Genzel , Gitta Kutyniok , Maximilian März

The Linear Representation Hypothesis asserts that the embeddings learned by neural networks can be understood as linear combinations of features corresponding to high-level concepts. Based on this ansatz, sparse autoencoders (SAEs) have…

Machine Learning · Computer Science 2026-01-29 Chiraag Kaushik , Davis Barch , Andrea Fanelli

This paper studies the effects of directional antenna element complex gain patterns and nonidealities in direction of arrival (DoA) estimation. We compare sparse arrays and classical uniform linear arrays, harnessing EM simulation tools to…

Signal Processing · Electrical Eng. & Systems 2025-12-01 Niko Lindvall , Mikko Heino , Robin Rajamäki , Mikko Valkama , Visa Koivunen

We present a compartmentalized approach to finding the maximum a-posteriori (MAP) estimate of a latent time series that obeys a dynamic stochastic model and is observed through noisy measurements. We specifically consider modern signal…

Optimization and Control · Mathematics 2018-10-15 Gabriel Schamberg , Demba Ba , Todd P. Coleman

Existing methods for multi-modal time series representation learning aim to disentangle the modality-shared and modality-specific latent variables. Although achieving notable performances on downstream tasks, they usually assume an…

Machine Learning · Computer Science 2024-05-28 Ruichu Cai , Zhifang Jiang , Zijian Li , Weilin Chen , Xuexin Chen , Zhifeng Hao , Yifan Shen , Guangyi Chen , Kun Zhang

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

We study the problem of signal estimation from non-linear observations when the signal belongs to a low-dimensional set buried in a high-dimensional space. A rough heuristic often used in practice postulates that non-linear observations may…

Information Theory · Computer Science 2015-11-17 Yaniv Plan , Roman Vershynin

After a decade of extensive study of the sparse representation synthesis model, we can safely say that this is a mature and stable field, with clear theoretical foundations, and appealing applications. Alongside this approach, there is an…

Numerical Analysis · Mathematics 2012-04-26 Sangnam Nam , Mike E. Davies , Michael Elad , Rémi Gribonval

We consider the problem of sparse atomic optimization, where the notion of "sparsity" is generalized to meaning some linear combination of few atoms. The definition of atomic set is very broad; popular examples include the standard basis,…

Optimization and Control · Mathematics 2019-12-30 Thomas Zhang

Designing a new class of rectangular two-dimensional sparse array to enhance the signal resolving capabilities with a limited number of sensors has always been a challenge. We explore the non-uniformity of the sparse arrays to enhance the…

Signal Processing · Electrical Eng. & Systems 2022-06-09 Kretika Goel , Monika Aggarwal , Subrat kar

We present a novel method to significantly speed up cosmological parameter sampling. The method relies on constructing an interpolation of the CMB-log-likelihood based on sparse grids, which is used as a shortcut for the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Mona Frommert , Dirk Pflueger , Thomas Riller , Martin Reinecke , Hans-Joachim Bungartz , Torsten Ensslin

We establish exact asymptotic expressions for the normalized mutual information and minimum mean-square-error (MMSE) of sparse linear regression in the sub-linear sparsity regime. Our result is achieved by a generalization of the adaptive…

Information Theory · Computer Science 2023-04-11 Lan V. Truong

Sparse linear regression with ill-conditioned Gaussian random designs is widely believed to exhibit a statistical/computational gap, but there is surprisingly little formal evidence for this belief, even in the form of examples that are…

Data Structures and Algorithms · Computer Science 2022-03-08 Jonathan A. Kelner , Frederic Koehler , Raghu Meka , Dhruv Rohatgi

Supervised learning methods with missing data have been extensively studied not just due to the techniques related to low-rank matrix completion. Also in unsupervised learning one often relies on imputation methods. As a matter of fact,…

Statistics Theory · Mathematics 2018-11-27 Andreas Elsener , Sara van de Geer

We propose a Bayesian methodology for estimating spiked covariance matrices with jointly sparse structure in high dimensions. The spiked covariance matrix is reparametrized in terms of the latent factor model, where the loading matrix is…

Methodology · Statistics 2019-01-31 Fangzheng Xie , Yanxun Xu , Carey E. Priebe , Joshua Cape

In underwater acoustics, shallow water environments act as modal dispersive waveguides when considering low-frequency sources. In this context, propagating signals can be described as a sum of few modal components, each of them propagating…

Signal Processing · Electrical Eng. & Systems 2020-12-01 Clément Dorffer , Thomas Paviet-Salomon , Gilles Le Chenadec , Angélique Drémeau

We consider the estimation of the transition matrix in the high-dimensional time-varying vector autoregression (TV-VAR) models. Our model builds on a general class of locally stationary VAR processes that evolve smoothly in time. We propose…

Statistics Theory · Mathematics 2017-10-03 Xin Ding , Ziyi Qiu , Xiaohui Chen

Velocity estimation is a cornerstone of the recently introduced near-field predictive beamforming. This paper derives the Cramer-Rao bounds (CRBs) for joint radial and transverse velocity estimation within a predictive beamforming framework…

Signal Processing · Electrical Eng. & Systems 2026-05-19 Khalid A. Alshumayri , Mudassir Masood , Ali. A. Nasir

Mixture-of-Experts (MoE) language models can reduce computational costs by 2-4$\times$ compared to dense models without sacrificing performance, making them more efficient in computation-bounded scenarios. However, MoE models generally…

Machine Learning · Computer Science 2024-04-09 Bowen Pan , Yikang Shen , Haokun Liu , Mayank Mishra , Gaoyuan Zhang , Aude Oliva , Colin Raffel , Rameswar Panda

The problem of estimating the frequencies of an exponential sum has been studied extensively over the last years. It can be understood as a sparse estimation problem, as it strives to identify the sparse representation of a signal using…

Numerical Analysis · Mathematics 2019-05-21 Benedikt Diederichs