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We consider model selection and estimation for partial spline models and propose a new regularization method in the context of smoothing splines. The regularization method has a simple yet elegant form, consisting of roughness penalty on…

Methodology · Statistics 2013-11-25 Guang Cheng , Hao Helen Zhang , Zuofeng Shang

There has been significant recent interest in the use of deep learning for regularizing imaging inverse problems. Most work in the area has focused on regularization imposed implicitly by convolutional neural networks (CNNs) pre-trained for…

Image and Video Processing · Electrical Eng. & Systems 2023-03-10 Zihao Zou , Jiaming Liu , Brendt Wohlberg , Ulugbek S. Kamilov

This paper considers large-scale linear ill-posed inverse problems whose solutions can be represented as sums of smooth and piecewise constant components. To solve such problems we consider regularizers consisting of two terms that must be…

Numerical Analysis · Mathematics 2022-06-30 Ali Gholami , Silvia Gazzola

Linear inverse problems are ubiquitous. Often the measurements do not follow a Gaussian distribution. Additionally, a model matrix with a large condition number can complicate the problem further by making it ill-posed. In this case, the…

The numerical solution of linear discrete ill-posed problems typically requires regularization, i.e., replacement of the available ill-conditioned problem by a nearby better conditioned one. The most popular regularization methods for…

Numerical Analysis · Mathematics 2016-02-11 Silvia Noschese , Lothar Reichel

Regularization is a central tool for addressing ill-posedness in inverse problems and statistical estimation, with the choice of a suitable penalty often determining the reliability and interpretability of downstream solutions. While recent…

Optimization and Control · Mathematics 2025-10-07 Oscar Leong , Eliza O'Reilly , Yong Sheng Soh

The sparse linear reconstruction problem is a core problem in signal processing which aims to recover sparse solutions to linear systems. The original problem regularized by the total number of nonzero components (also known as $L_0$…

Optimization and Control · Mathematics 2025-11-19 Yuyuan Ouyang , Kyle Yates

The goal of regression and classification methods in supervised learning is to minimize the empirical risk, that is, the expectation of some loss function quantifying the prediction error under the empirical distribution. When facing scarce…

Optimization and Control · Mathematics 2019-07-15 Soroosh Shafieezadeh-Abadeh , Daniel Kuhn , Peyman Mohajerin Esfahani

Recent advances in convolutional neural networks(CNNs) usually come with the expense of excessive computational overhead and memory footprint. Network compression aims to alleviate this issue by training compact models with comparable…

Computer Vision and Pattern Recognition · Computer Science 2021-05-17 Xin-Yu Zhang , Kai Zhao , Taihong Xiao , Ming-Ming Cheng , Ming-Hsuan Yang

Non-stationary blind super-resolution is an extension of the traditional super-resolution problem, which deals with the problem of recovering fine details from coarse measurements. The non-stationary blind super-resolution problem appears…

Information Theory · Computer Science 2019-10-09 Shuang Li , Michael B. Wakin , Gongguo Tang

In text classification, the problem of overfitting arises due to the high dimensionality, making regularization essential. Although classic regularizers provide sparsity, they fail to return highly accurate models. On the contrary,…

Machine Learning · Computer Science 2018-10-10 Konstantinos Skianis , Nikolaos Tziortziotis , Michalis Vazirgiannis

Low-rank learning has attracted much attention recently due to its efficacy in a rich variety of real-world tasks, e.g., subspace segmentation and image categorization. Most low-rank methods are incapable of capturing low-dimensional…

Computer Vision and Pattern Recognition · Computer Science 2016-11-16 Ping Li , Jun Yu , Meng Wang , Luming Zhang , Deng Cai , Xuelong Li

In recent years, a variety of learned regularization frameworks for solving inverse problems in imaging have emerged. These offer flexible modeling together with mathematical insights. The proposed methods differ in their architectural…

Many inverse problems and signal processing problems involve low-rank regularizers based on the nuclear norm. Commonly, proximal gradient methods (PGM) are adopted to solve this type of non-smooth problems as they can offer fast and…

Signal Processing · Electrical Eng. & Systems 2025-11-25 Rodrigo A. Lobos , Javier Salazar Cavazos , Raj Rao Nadakuditi , Jeffrey A. Fessler

A new method, called the method of self-similar approximants, and its recent developments are described. The method is based on the ideas of renormalization group theory and optimal control theory. It allows for the effective extrapolation…

Mathematical Physics · Physics 2025-05-20 V. I. Yukalov , E. P. Yukalova

The de-facto standard approach of promoting sparsity by means of $\ell_1$-regularization becomes ineffective in the presence of simplex constraints, i.e.,~the target is known to have non-negative entries summing up to a given constant. The…

Methodology · Statistics 2016-05-04 Ping Li , Syama Sundar Rangapuram , Martin Slawski

Variational methods have become an important kind of methods in signal and image restoration - a typical inverse problem. One important minimization model consists of the squared $\ell_2$ data fidelity (corresponding to Gaussian noise) and…

Numerical Analysis · Mathematics 2018-06-15 Chunlin Wu , Zhifang Liu , Shuang Wen

In this work, we propose an algorithm for solving exact sparse linear regression problems over a network in a distributed manner. Particularly, we consider the problem where data is stored among different computers or agents that seek to…

Optimization and Control · Mathematics 2022-04-04 Tu Anh-Nguyen , César A. Uribe

We focus on solving the clustered lasso problem, which is a least squares problem with the $\ell_1$-type penalties imposed on both the coefficients and their pairwise differences to learn the group structure of the regression parameters.…

Optimization and Control · Mathematics 2019-05-02 Meixia Lin , Yong-Jin Liu , Defeng Sun , Kim-Chuan Toh

We introduce a method for fast estimation of data-adapted, spatio-temporally dependent regularization parameter-maps for variational image reconstruction, focusing on total variation (TV)-minimization. Our approach is inspired by recent…