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We consider the problem of clustering datasets in the presence of arbitrary outliers. Traditional clustering algorithms such as k-means and spectral clustering are known to perform poorly for datasets contaminated with even a small number…

Machine Learning · Statistics 2021-02-02 Prateek R. Srivastava , Purnamrita Sarkar , Grani A. Hanasusanto

A fundamental challenge confronting supervised graph outlier detection algorithms is the prevalent problem of class imbalance, where the scarcity of outlier instances compared to normal instances often results in suboptimal performance.…

Machine Learning · Computer Science 2024-11-26 Kay Liu , Hengrui Zhang , Ziqing Hu , Fangxin Wang , Philip S. Yu

Anomalies (or outliers) are prevalent in real-world empirical observations and potentially mask important underlying structures. Accurate identification of anomalous samples is crucial for the success of downstream data analysis tasks. To…

Machine Learning · Computer Science 2022-08-25 Ofir Lindenbaum , Yariv Aizenbud , Yuval Kluger

We consider the problem of recovering an unknown signal $\pmb{x}_0\in \mathbb{R}^{n}$ from phaseless measurements. In this paper, we study the convex phase retrieval problem via PhaseLift from linear Gaussian measurements perturbed by…

Information Theory · Computer Science 2023-11-23 Gao Huang , Song Li , Hang Xu

In this paper, we consider robust system identification under sparse outliers and random noises. In this problem, system parameters are observed through a Toeplitz matrix. All observations are subject to random noises and a few are…

Information Theory · Computer Science 2013-05-28 Weiyu Xu , Erwei Bai , Myung Cho

In a corpus of data, outliers are either errors: mistakes in the data that are counterproductive, or are unique: informative samples that improve model robustness. Identifying outliers can lead to better datasets by (1) removing noise in…

Out-of-distribution detection (OOD) deals with anomalous input to neural networks. In the past, specialized methods have been proposed to reject predictions on anomalous input. Similarly, it was shown that feature extraction models in…

Machine Learning · Computer Science 2022-01-25 Jan Diers , Christian Pigorsch

The phase retrieval problem asks to recover a natural signal $y_0 \in \mathbb{R}^n$ from $m$ quadratic observations, where $m$ is to be minimized. As is common in many imaging problems, natural signals are considered sparse with respect to…

Information Theory · Computer Science 2018-07-12 Paul Hand , Oscar Leong , Vladislav Voroninski

Node outlier detection in attributed graphs is a challenging problem for which there is no method that would work well across different datasets. Motivated by the state-of-the-art results of score-based models in graph generative modeling,…

Machine Learning · Computer Science 2023-06-28 Dmitrii Gavrilev , Evgeny Burnaev

A new method for outlier detection and generation is introduced by lifting data into the space of probability distributions which are not analytically expressible, but from which samples can be drawn using a neural generator. Given a…

Machine Learning · Computer Science 2020-12-24 Stefano Giovanni Rizzo , Linsey Pang , Yixian Chen , Sanjay Chawla

In this paper, we carry out a unified study for $L_1$ over $L_2$ sparsity promoting models, which are widely used in the regime of coherent dictionaries for recovering sparse nonnegative/arbitrary signals. First, we provide a unified…

Optimization and Control · Mathematics 2023-01-24 Min Tao , Xiao-Ping Zhang

This work addresses the robust reconstruction problem of a sparse signal from compressed measurements. We propose a robust formulation for sparse reconstruction which employs the $\ell_1$-norm as the loss function for the residual error and…

Information Theory · Computer Science 2017-03-30 Fei Wen , Yuan Yang , Ling Pei , Wenxian Yu , Peilin Liu

The unsupervised outlier detection (UOD) problem refers to a task to identify inliers given training data which contain outliers as well as inliers, without any labeled information about inliers and outliers. It has been widely recognized…

Machine Learning · Statistics 2024-07-17 Dongha Kim , Jaesung Hwang , Jongjin Lee , Kunwoong Kim , Yongdai Kim

The storage and computation requirements of Convolutional Neural Networks (CNNs) can be prohibitive for exploiting these models over low-power or embedded devices. This paper reduces the computational complexity of the CNNs by minimizing an…

Neural and Evolutionary Computing · Computer Science 2017-01-17 Farkhondeh Kiaee , Christian Gagné , Mahdieh Abbasi

Euclidean embedding from noisy observations containing outlier errors is an important and challenging problem in statistics and machine learning. Many existing methods would struggle with outliers due to a lack of detection ability. In this…

Machine Learning · Statistics 2020-12-24 Qian Zhang , Xinyuan Zhao , Chao Ding

Gaussian Graphical Models (GGMs) are popular tools for studying network structures. However, many modern applications such as gene network discovery and social interactions analysis often involve high-dimensional noisy data with outliers or…

Machine Learning · Statistics 2015-10-30 Eunho Yang , Aurélie C. Lozano

Large outliers break down linear and nonlinear regression models. Robust regression methods allow one to filter out the outliers when building a model. By replacing the traditional least squares criterion with the least trimmed squares…

Optimization and Control · Mathematics 2012-06-07 Gleb Beliakov , Andrei Kelarev , John Yearwood

Given a real-valued function $f$ defined over a manifold $M$ embedded in $\mathbb{R}^d$, we are interested in recovering structural information about $f$ from the sole information of its values on a finite sample $P$. Existing methods…

Computational Geometry · Computer Science 2015-04-08 Mickaël Buchet , Frédéric Chazal , Tamal K. Dey , Fengtao Fan , Steve Y. Oudot , Yusu Wang

Outliers are samples that are generated by different mechanisms from other normal data samples. Graphs, in particular social network graphs, may contain nodes and edges that are made by scammers, malicious programs or mistakenly by normal…

Social and Information Networks · Computer Science 2016-06-22 Honglei Zhang , Serkan Kiranyaz , Moncef Gabbouj

In this work, we propose a (linearized) Alternating Direction Method-of-Multipliers (ADMM) algorithm for minimizing a convex function subject to a nonconvex constraint. We focus on the special case where such constraint arises from the…

Machine Learning · Computer Science 2019-07-09 Fabian Latorre Gómez , Armin Eftekhari , Volkan Cevher