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We describe a stochastic, dynamical system capable of inference and learning in a probabilistic latent variable model. The most challenging problem in such models - sampling the posterior distribution over latent variables - is proposed to…

Machine Learning · Statistics 2022-07-26 Michael Y. -S. Fang , Mayur Mudigonda , Ryan Zarcone , Amir Khosrowshahi , Bruno A. Olshausen

In this paper, we show a way to exploit sparsity in the problem data in a primal-dual potential reduction method for solving a class of semidefinite programs. When the problem data is sparse, the dual variable is also sparse, but the primal…

Numerical Analysis · Mathematics 2025-10-20 Gun Srijuntongsiri , Stephen A. Vavasis

The sparsity of signals in a transform domain or dictionary has been exploited in applications such as compression, denoising and inverse problems. More recently, data-driven adaptation of synthesis dictionaries has shown promise compared…

Machine Learning · Computer Science 2019-06-14 Saiprasad Ravishankar , Raj Rao Nadakuditi , Jeffrey A. Fessler

A popular approach within the signal processing and machine learning communities consists in modelling signals as sparse linear combinations of atoms selected from a learned dictionary. While this paradigm has led to numerous empirical…

Machine Learning · Computer Science 2015-08-25 Rémi Gribonval , Rodolphe Jenatton , Francis Bach

Sparse linear regression is a central problem in high-dimensional statistics. We study the correlated random design setting, where the covariates are drawn from a multivariate Gaussian $N(0,\Sigma)$, and we seek an estimator with small…

Data Structures and Algorithms · Computer Science 2023-05-29 Jonathan Kelner , Frederic Koehler , Raghu Meka , Dhruv Rohatgi

Sparse dictionary learning is a popular method for representing signals as linear combinations of a few elements from a dictionary that is learned from the data. In the classical setting, signals are represented as vectors and the…

Optimization and Control · Mathematics 2019-09-20 Evan Schwab , Benjamin D. Haeffele , René Vidal , Nicolas Charon

We propose a new algorithm for recovery of sparse signals from their compressively sensed samples. The proposed algorithm benefits from the strategy of gradual movement to estimate the positions of non-zero samples of sparse signal. We…

Information Theory · Computer Science 2012-04-04 Seyed Hossein Hosseini , Mahrokh G. Shayesteh

We propose a probabilistic semantic filtering framework in which parameters of a dynamical system are inferred and associated with a closed set of semantic classes in a map. We extend existing methods to a multi-parameter setting using a…

Systems and Control · Electrical Eng. & Systems 2026-01-15 Marcus Greiff , Ray Zhang , Thomas Lew , John Subosits

Compressive sensing is a powerful technique for recovering sparse solutions of underdetermined linear systems, which is often encountered in uncertainty quantification analysis of expensive and high-dimensional physical models. We perform…

IR models using a pretrained language model significantly outperform lexical approaches like BM25. In particular, SPLADE, which encodes texts to sparse vectors, is an effective model for practical use because it shows robustness to…

Computation and Language · Computer Science 2022-11-11 Hiroki Iida , Naoaki Okazaki

Recently, considerable research efforts have been devoted to the design of methods to learn from data overcomplete dictionaries for sparse coding. However, learned dictionaries require the solution of an optimization problem for coding new…

Machine Learning · Computer Science 2010-11-17 Curzio Basso , Matteo Santoro , Alessandro Verri , Silvia Villa

In sparse coding, we attempt to extract features of input vectors, assuming that the data is inherently structured as a sparse superposition of basic building blocks. Similarly, neural networks perform a given task by learning features of…

Machine Learning · Computer Science 2022-02-16 Deborah Pereg , Israel Cohen , Anthony A. Vassiliou

Dictionary Learning (DL) is one of the leading sparsity promoting techniques in the context of image classification, where the "dictionary" matrix D of images and the sparse matrix X are determined so as to represent a redundant image…

Numerical Analysis · Mathematics 2022-03-10 Domitilla Brandoni , Margherita Porcelli , Valeria Simoncini

We give an efficient algorithm for finding sparse approximate solutions to linear systems of equations with nonnegative coefficients. Unlike most known results for sparse recovery, we do not require {\em any} assumption on the matrix other…

Data Structures and Algorithms · Computer Science 2015-01-09 Aditya Bhaskara , Ananda Theertha Suresh , Morteza Zadimoghaddam

This paper introduces an efficient sparse recovery approach for Polynomial Chaos (PC) expansions, which promotes the sparsity by breaking the dimensionality of the problem. The proposed algorithm incrementally explores sub-dimensional…

Computation · Statistics 2017-04-05 Negin Alemazkoor , Hadi Meidani

High dimensional covariance estimation and graphical models is a contemporary topic in statistics and machine learning having widespread applications. An important line of research in this regard is to shrink the extreme spectrum of the…

Methodology · Statistics 2016-06-28 Sang-Yun Oh , Bala Rajaratnam , Joong-Ho Won

In this paper we consider the dictionary learning problem for sparse representation. We first show that this problem is NP-hard by polynomial time reduction of the densest cut problem. Then, using successive convex approximation strategies,…

Machine Learning · Computer Science 2015-11-06 Meisam Razaviyayn , Hung-Wei Tseng , Zhi-Quan Luo

In this work we investigate the practicality of stochastic gradient descent and recently introduced variants with variance-reduction techniques in imaging inverse problems. Such algorithms have been shown in the machine learning literature…

Optimization and Control · Mathematics 2021-01-26 Junqi Tang , Karen Egiazarian , Mohammad Golbabaee , Mike Davies

Sparse representations have proven their efficiency in solving a wide class of inverse problems encountered in signal and image processing. Conversely, enforcing the information to be spread uniformly over representation coefficients…

Machine Learning · Statistics 2017-12-29 Clément Elvira , Pierre Chainais , Nicolas Dobigeon

The dictionary matching problem preprocesses a set of patterns and finds all occurrences of each of the patterns in a text when it is provided. We focus on the dynamic setting, in which patterns can be inserted to and removed from the…

Data Structures and Algorithms · Computer Science 2013-02-04 Shoshana Marcus , Dina Sokol