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Complex networks have now become integral parts of modern information infrastructures. This paper proposes a user-centric method for detecting anomalies in heterogeneous information networks, in which nodes and/or edges might be from…

Social and Information Networks · Computer Science 2018-10-22 Vahid Ranjbar , Mostafa Salehi , Pegah Jandaghi , Mahdi Jalili

Environmental and instrumental conditions can cause anomalies in astronomical images, which can potentially bias all kinds of measurements if not excluded. Detection of the anomalous images is usually done by human eyes, which is slow and…

Instrumentation and Methods for Astrophysics · Physics 2023-10-25 Pedro Alonso , Jun Zhang , Xiao-Dong Li

We propose an anomaly detection technique for high-resolution X-ray spectroscopy. The method is based on the neural network architecture variational autoencoder, and requires only {\it normal} samples for training. We implement the network…

Instrumentation and Methods for Astrophysics · Physics 2019-06-12 Y. Ichinohe , S. Yamada

This paper is concerned with a direct sampling method for imaging the support of a frequency-dependent source term embedded in a homogeneous and isotropic medium. The source term is given by the Fourier transform of a time-dependent source…

Numerical Analysis · Mathematics 2022-12-12 Hongxia Guo , Guanghui Hu , Mengjie Zhao

Anomalies can be defined as any non-random structure which deviates from normality. Anomaly detection methods reported in the literature are numerous and diverse, as what is considered anomalous usually varies depending on particular…

Computer Vision and Pattern Recognition · Computer Science 2021-10-07 Matias Tailanian , Pablo Musé , Álvaro Pardo

In this paper, we consider a simple coding scheme for spatial modulation (SM), where the same set of active transmit antennas is repeatedly used over consecutive multiple transmissions. Based on a Gaussian approximation, an approximate…

Information Theory · Computer Science 2019-01-01 Jinho Choi

Anomaly detection is concerned with a wide range of applications such as fault detection, system monitoring, and event detection. Identifying anomalies from metering data obtained from smart metering system is a critical task to enhance…

Machine Learning · Computer Science 2021-12-08 Sangkeum Lee , Hojun Jin , Sarvar Hussain Nengroo , Yoonmee Doh , Chungho Lee , Taewook Heo , Dongsoo Har

We present a technique for the accurate estimation of large-scale errors in an antenna surface using astronomical sources and detectors. The technique requires several out-of-focus images of a compact source and the signal-to-noise ratio…

Astrophysics · Physics 2009-11-11 B. Nikolic , R. E. Hills , J. S. Richer

We propose Gumbel Noise Score Matching (GNSM), a novel unsupervised method to detect anomalies in categorical data. GNSM accomplishes this by estimating the scores, i.e. the gradients of log likelihoods w.r.t.~inputs, of continuously…

Machine Learning · Computer Science 2023-04-07 Ahsan Mahmood , Junier Oliva , Martin Styner

Nearest neighbor (kNN) methods utilizing deep pre-trained features exhibit very strong anomaly detection performance when applied to entire images. A limitation of kNN methods is the lack of segmentation map describing where the anomaly…

Computer Vision and Pattern Recognition · Computer Science 2021-02-04 Niv Cohen , Yedid Hoshen

Unsupervised anomaly detection and localization is crucial to the practical application when collecting and labeling sufficient anomaly data is infeasible. Most existing representation-based approaches extract normal image features with a…

Computer Vision and Pattern Recognition · Computer Science 2021-11-17 Jiawei Yu , Ye Zheng , Xiang Wang , Wei Li , Yushuang Wu , Rui Zhao , Liwei Wu

We propose a non-parametric anomaly detection algorithm for high dimensional data. We first rank scores derived from nearest neighbor graphs on $n$-point nominal training data. We then train limited complexity models to imitate these scores…

Machine Learning · Statistics 2016-01-25 Jonathan Root , Venkatesh Saligrama , Jing Qian

We consider the problem of detecting a rectangle of activation in a grid of sensors in d-dimensions with noisy measurements. This has applications to massive surveillance projects and anomaly detection in large datasets in which one detects…

Statistics Theory · Mathematics 2014-09-26 James Sharpnack , Ery Arias-Castro

Accurate and automated detection of anomalous samples in a natural image dataset can be accomplished with a probabilistic model for end-to-end modeling of images. Such images have heterogeneous complexity, however, and a probabilistic model…

Machine Learning · Computer Science 2018-09-05 Takashi Matsubara , Kenta Hama , Ryosuke Tachibana , Kuniaki Uehara

The method of angular photonic correlations of spontaneous emission is introduced as an experimental, purely optical scheme to characterize disorder in semiconductor nanostructures. The theoretical expression for the angular correlations is…

Disordered Systems and Neural Networks · Physics 2007-05-23 P. Bozsoki , P. Thomas , M. Kira , W. Hoyer , T. Meier , S. W. Koch , K. Maschke , I. Varga , H. Stolz

Anomaly detection is the task of identifying abnormal samples in large unlabeled datasets. While the advent of foundation models has produced powerful zero-shot anomaly detection methods, their deployment in practice is often hindered by…

Machine Learning · Computer Science 2024-09-17 Clement Fung , Chen Qiu , Aodong Li , Maja Rudolph

Scanning near-field optical microscopy is one of the most effective techniques for spectroscopy of nanoscale systems. However, inferring optical constants from the measured near-field signal can be challenging because of a complicated and…

Optics · Physics 2023-04-19 Yueqi Zhao , Xinzhong Chen , Ziheng Yao , Mengkun Liu , Michael M. Fogler

Deep generative models have emerged as promising tools for detecting arbitrary anomalies in data, dispensing with the necessity for manual labelling. Recently, autoregressive transformers have achieved state-of-the-art performance for…

This paper presents a non-parametric method for 3-D imaging of natural volumes using Synthetic Aperture Radar tomography. This array processing-based technique aims at characterizing a spatially distributed density of incoherent sources,…

Signal Processing · Electrical Eng. & Systems 2025-03-18 Colin Cros , Laurent Ferro-Famil

Timely detection of abrupt anomalies is crucial for real-time monitoring and security of modern systems producing high-dimensional data. With this goal, we propose effective and scalable algorithms. Proposed algorithms are nonparametric as…

Machine Learning · Computer Science 2020-02-19 Mehmet Necip Kurt , Yasin Yilmaz , Xiaodong Wang