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Stein showed that the multivariate sample mean is outperformed by "shrinking" to a constant target vector. Ledoit and Wolf extended this approach to the sample covariance matrix and proposed a multiple of the identity as shrinkage target.…

Methodology · Statistics 2014-12-08 Daniel Bartz , Johannes Höhne , Klaus-Robert Müller

A regularization algorithm using inexact function values and inexact derivatives is proposed and its evaluation complexity analyzed. This algorithm is applicable to unconstrained problems and to problems with inexpensive constraints (that…

Optimization and Control · Mathematics 2019-04-22 S. Bellavia , G. Gurioli , B. Morini , Ph. L. Toint

Bayesian inference with empirical likelihood faces a challenge as the posterior domain is a proper subset of the original parameter space due to the convex hull constraint. We propose a regularized exponentially tilted empirical likelihood…

Methodology · Statistics 2026-04-23 Eunseop Kim , Steven N. MacEachern , Mario Peruggia

The limit distribution of the nonparametric maximum likelihood estimator for interval censored data with more than one observation time per unobservable observation, is still unknown in general. For the so-called separated case, where one…

Statistics Theory · Mathematics 2026-02-12 Piet Groeneboom

Low-complexity non-smooth convex regularizers are routinely used to impose some structure (such as sparsity or low-rank) on the coefficients for linear predictors in supervised learning. Model consistency consists then in selecting the…

Optimization and Control · Mathematics 2019-01-17 Jalal Fadili , Guillaume Garrigos , Jérome Malick , Gabriel Peyré

This paper considers inference in a linear regression model with random right censoring and outliers. The number of outliers can grow with the sample size while their proportion goes to zero. The model is semiparametric and we make only…

Statistics Theory · Mathematics 2021-10-06 Jad Beyhum , Ingrid Van Keilegom

Unbiased estimators are introduced for averaged Bregman divergences which generalize Stein's Unbiased (Predictive) Risk Estimator, and the minimization of these estimators is proposed as a regularization parameter selection method for…

Numerical Analysis · Mathematics 2021-11-22 Elias S. Helou , Sandra A. Santos , Lucas E. A. Simões

Over the past few years, trace regression models have received considerable attention in the context of matrix completion, quantum state tomography, and compressed sensing. Estimation of the underlying matrix from regularization-based…

Machine Learning · Statistics 2015-04-24 Martin Slawski , Ping Li , Matthias Hein

This paper studies least-square regression penalized with partly smooth convex regularizers. This class of functions is very large and versatile allowing to promote solutions conforming to some notion of low-complexity. Indeed, they force…

Optimization and Control · Mathematics 2014-07-01 Samuel Vaiter , Gabriel Peyré , Jalal M. Fadili

In this paper we introduce a new clustering technique called Regularity Clustering. This new technique is based on the practical variants of the two constructive versions of the Regularity Lemma, a very useful tool in graph theory. The…

Combinatorics · Mathematics 2012-10-01 Gábor N. Sárközy , Fei Song , Endre Szemerédi , Shubhendu Trivedi

In this paper, we present perturbation analysis and randomized algorithms for the total least squares (TLS) problems. We derive the perturbation bound and check its sharpness by numerical experiments. Motivated by the recently popular…

Numerical Analysis · Mathematics 2014-11-12 Pengpeng Xie , Yimin Wei , Hua Xiang

The optimization of the variance supplemented by a budget constraint and an asymmetric $\ell_1$ regularizer is carried out analytically by the replica method borrowed from the theory of disordered systems. The asymmetric regularizer allows…

Portfolio Management · Quantitative Finance 2018-07-16 Imre Kondor , Gábor Papp , Fabio Caccioli

To reduce the x-ray dose in computerized tomography (CT), many constrained optimization approaches have been proposed aiming at minimizing a regularizing function that measures lack of consistency with some prior knowledge about the object…

Medical Physics · Physics 2017-04-05 Edgar Garduño , Gabor T. Herman

We consider optimization algorithms that successively minimize simple Taylor-like models of the objective function. Methods of Gauss-Newton type for minimizing the composition of a convex function and a smooth map are common examples. Our…

Optimization and Control · Mathematics 2016-10-12 Dmitriy Drusvyatskiy , Alexander D. Ioffe , Adrian S. Lewis

Covariance matrices play a major role in statistics, signal processing and machine learning applications. This paper focuses on the \textit{semiparametric} covariance/scatter matrix estimation problem in elliptical distributions. The class…

Signal Processing · Electrical Eng. & Systems 2020-10-28 Stefano Fortunati , Alexandre Renaux , Frédéric Pascal

The discrete distribution of the length of longest increasing subsequences in random permutations of $n$ integers is deeply related to random matrix theory. In a seminal work, Baik, Deift and Johansson provided an asymptotics in terms of…

Combinatorics · Mathematics 2024-06-21 Folkmar Bornemann

This paper proposes minimum sliced distance estimation in structural econometric models with possibly parameter-dependent supports. In contrast to likelihood-based estimation, we show that under mild regularity conditions, the minimum…

Econometrics · Economics 2024-12-10 Yanqin Fan , Hyeonseok Park

In a linear regression model with random design, we consider a family of candidate models from which we want to select a `good' model for prediction out-of-sample. We fit the models using block shrinkage estimators, and we focus on the…

Statistics Theory · Mathematics 2018-09-13 Hannes Leeb , Nina Senitschnig

One of the goals in scaling sequential machine learning methods pertains to dealing with high-dimensional data spaces. A key related challenge is that many methods heavily depend on obtaining the inverse covariance matrix of the data. It is…

Computation · Statistics 2017-07-28 Tomer Lancewicki

In this paper, we first formalize the problem to be solved, i.e., the Scatter Problem (SP). We then show that SP cannot be deterministically solved. Next, we propose a randomized algorithm for this problem. The proposed solution is…

Distributed, Parallel, and Cluster Computing · Computer Science 2016-08-14 Yoann Dieudonné , Franck Petit
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