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In this article the most fundamental decomposition-based optimization method - block coordinate search, based on the sequential decomposition of problems in subproblems - and building performance simulation programs are used to reason about…

Optimization and Control · Mathematics 2016-09-12 Gian Luca Brunetti

Sparse dictionary learning has been a rapidly growing technique in mechanistic interpretability to attack superposition and extract more human-understandable features from model activations. We ask a further question based on the extracted…

Machine Learning · Computer Science 2024-02-20 Zhengfu He , Xuyang Ge , Qiong Tang , Tianxiang Sun , Qinyuan Cheng , Xipeng Qiu

In unsupervised learning, an unbiased uniform sampling strategy is typically used, in order that the learned features faithfully encode the statistical structure of the training data. In this work, we explore whether active example…

Machine Learning · Computer Science 2015-04-01 Tomoki Tsuchida , Garrison W. Cottrell

Sparse coding or sparse dictionary learning has been widely used to recover underlying structure in many kinds of natural data. Here, we provide conditions guaranteeing when this recovery is universal; that is, when sparse codes and…

Neurons and Cognition · Quantitative Biology 2016-11-18 Christopher J. Hillar , Friedrich T. Sommer

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

In the dictionary learning (or sparse coding) problem, we are given a collection of signals (vectors in $\mathbb{R}^d$), and the goal is to find a "basis" in which the signals have a sparse (approximate) representation. The problem has…

Machine Learning · Computer Science 2019-05-30 Aditya Bhaskara , Wai Ming Tai

Sparse coding with dictionary learning (DL) has shown excellent classification performance. Despite the considerable number of existing works, how to obtain features on top of which dictionaries can be better learned remains an open and…

Computer Vision and Pattern Recognition · Computer Science 2016-08-08 Weiyang Liu , Zhiding Yu , Yandong Wen , Rongmei Lin , Meng Yang

Methods exploiting sparsity have been popular in imaging and signal processing applications including compression, denoising, and imaging inverse problems. Data-driven approaches such as dictionary learning and transform learning enable one…

Machine Learning · Computer Science 2018-02-05 Saiprasad Ravishankar , Anna Ma , Deanna Needell

Learned sparse retrieval (LSR) is a popular method for first-stage retrieval because it combines the semantic matching of language models with efficient CPU-friendly algorithms. Previous work aggregates blocks into "superblocks" to quickly…

Information Retrieval · Computer Science 2026-02-04 Parker Carlson , Wentai Xie , Rohil Shah , Tao Yang

Sparse coding (SC) is an automatic feature extraction and selection technique that is widely used in unsupervised learning. However, conventional SC vectorizes the input images, which breaks apart the local proximity of pixels and destructs…

Computer Vision and Pattern Recognition · Computer Science 2017-03-29 Fei Jiang , Xiao-Yang Liu , Hongtao Lu , Ruimin Shen

The concept of deep dictionary learning has been recently proposed. Unlike shallow dictionary learning which learns single level of dictionary to represent the data, it uses multiple layers of dictionaries. So far, the problem could only be…

Machine Learning · Computer Science 2019-12-24 Vanika Singhal , Angshul Majumdar

The sparsity of natural signals and images in a transform domain or dictionary has been extensively exploited in several applications such as compression, denoising and inverse problems. More recently, data-driven adaptation of synthesis…

Machine Learning · Computer Science 2017-04-24 Saiprasad Ravishankar , Raj Rao Nadakuditi , Jeffrey A. Fessler

Dictionary learning, the problem of recovering a sparsely used matrix $\mathbf{D} \in \mathbb{R}^{M \times K}$ and $N$ $s$-sparse vectors $\mathbf{x}_i \in \mathbb{R}^{K}$ from samples of the form $\mathbf{y}_i = \mathbf{D}\mathbf{x}_i$, is…

Machine Learning · Computer Science 2023-03-29 Alexei Novikov , Stephen White

Data is said to follow the transform (or analysis) sparsity model if it becomes sparse when acted on by a linear operator called a sparsifying transform. Several algorithms have been designed to learn such a transform directly from data,…

Machine Learning · Statistics 2019-01-30 Luke Pfister , Yoram Bresler

Subspace learning is an important problem, which has many applications in image and video processing. It can be used to find a low-dimensional representation of signals and images. But in many applications, the desired signal is heavily…

Computer Vision and Pattern Recognition · Computer Science 2017-07-13 Shervin Minaee , Yao Wang

Recently, great attention was intended toward overcomplete dictionaries and the sparse representations they can provide. In a wide variety of signal processing problems, sparsity serves a crucial property leading to high performance.…

Multimedia · Computer Science 2008-12-15 SeyyedMajid Valiollahzadeh , Mohammad Nazari , Massoud Babaie-Zadeh , Christian Jutten

Sparse approximations using highly over-complete dictionaries is a state-of-the-art tool for many imaging applications including denoising, super-resolution, compressive sensing, light-field analysis, and object recognition. Unfortunately,…

Computer Vision and Pattern Recognition · Computer Science 2014-12-03 Ali Ayremlou , Thomas Goldstein , Ashok Veeraraghavan , Richard Baraniuk

Sparse coding (SC) is attracting more and more attention due to its comprehensive theoretical studies and its excellent performance in many signal processing applications. However, most existing sparse coding algorithms are nonconvex and…

Machine Learning · Computer Science 2017-09-12 Xiaodong Feng , Zhiwei Tang , Sen Wu

In order to improve the performance of least mean square (LMS)-based adaptive filtering for identifying block-sparse systems, a new adaptive algorithm called block-sparse LMS (BS-LMS) is proposed in this paper. The basis of the proposed…

Information Theory · Computer Science 2015-10-28 Shuyang Jiang , Yuantao Gu

Distributional models are derived from co-occurrences in a corpus, where only a small proportion of all possible plausible co-occurrences will be observed. This results in a very sparse vector space, requiring a mechanism for inferring…

Computation and Language · Computer Science 2016-08-25 Thomas Kober , Julie Weeds , Jeremy Reffin , David Weir