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In this work, we investigate a class of elliptic inverse problems and aim to simultaneously recover multiple inhomogeneous inclusions arising from two different physical parameters, using very limited boundary Cauchy data collected only at…

Numerical Analysis · Mathematics 2020-06-05 Yat Tin Chow , Fuqun Han , Jun Zou

This paper proposes to use set features for detecting anomalies in samples that consist of unusual combinations of normal elements. Many leading methods discover anomalies by detecting an unusual part of a sample. For example,…

Computer Vision and Pattern Recognition · Computer Science 2025-03-20 Niv Cohen , Issar Tzachor , Yedid Hoshen

Fine-grained anomaly detection has recently been dominated by segmentation based approaches. These approaches first classify each element of the sample (e.g., image patch) as normal or anomalous and then classify the entire sample as…

Computer Vision and Pattern Recognition · Computer Science 2023-03-03 Niv Cohen , Issar Tzachor , Yedid Hoshen

Anomaly detection is the process of identifying atypical data samples that significantly deviate from the majority of the dataset. In the realm of clinical screening and diagnosis, detecting abnormalities in medical images holds great…

Computer Vision and Pattern Recognition · Computer Science 2023-10-11 Xianyao Hu , Congming Jin

We consider the application of a subspace migration (SM) algorithm to quickly identify small objects in microwave imaging. In various problems, it is easy to measure the diagonal elements of the scattering matrix if the location of the…

Numerical Analysis · Mathematics 2025-10-13 Won-Kwang Park

The goal of anomaly detection is to identify examples that deviate from normal or expected behavior. We tackle this problem for images. We consider a two-phase approach. First, using normal examples, a convolutional autoencoder (CAE) is…

Computer Vision and Pattern Recognition · Computer Science 2020-03-20 Natasa Sarafijanovic-Djukic , Jesse Davis

In this paper, the instantaneous frequency estimation of nonstationary signals is considered. The instantaneous frequency is estimated from the timefrequency representation where certain percent of the coefficients is missing. The…

Signal Processing · Electrical Eng. & Systems 2019-02-08 Bozidar Androvic , Marko Kovac , Andjela Kandic

Direct imaging methods recover the presence, position, and shape of the unknown obstacles in time-harmonic inverse scattering without a priori knowledge of either the physical properties or the number of disconnected components of the…

Analysis of PDEs · Mathematics 2023-11-29 General Ozochiawaeze

In this work, we investigate the diffusive optical tomography (DOT) problem in the case that limited boundary measurements are available. Motivated by the direct sampling method (DSM), we develop a deep direct sampling method (DDSM) to…

Numerical Analysis · Mathematics 2021-05-10 Jiahua Jiang , Yi Li , Ruchi Guo

We consider the inverse problem of determining the geometry of penetrable objects from scattering data generated by one incident wave at a fixed frequency. We first study an orthogonality sampling type method which is fast, simple to…

Numerical Analysis · Mathematics 2022-07-21 Thu Le , Dinh-Liem Nguyen , Vu Nguyen , Trung Truong

In this paper, we consider an inverse electromagnetic medium scattering problem of reconstructing unknown objects from time-dependent boundary measurements. A novel time-domain direct sampling method is developed for determining the…

Numerical Analysis · Mathematics 2024-10-11 Chen Geng , Minghui Song , Xianchao Wang , Yuliang Wang

This paper describes the implementation of the direct solution method (DSM) using radial spectral elements for the calculation of synthetic seismograms in self-gravitating, spherically symmetric, non-rotating, anelastic, and transversely…

Geophysics · Physics 2026-03-10 Alex D. C. Myhill , David Al-Attar

Anomaly detection is a fundamental task in machine learning and data mining, with significant applications in cybersecurity, industrial fault diagnosis, and clinical disease monitoring. Traditional methods, such as statistical modeling and…

Machine Learning · Computer Science 2025-05-09 Yi Chen

Anomalies are strange data points; they usually represent an unusual occurrence. Anomaly detection is presented from the perspective of Wireless sensor networks. Different approaches have been taken in the past, as we will see, not only to…

Machine Learning · Computer Science 2017-08-30 Pelumi Oluwasanya

The definition of anomaly detection is the identification of an unexpected event. Real-time detection of extreme events such as wildfires, cyclones, or floods using satellite data has become crucial for disaster management. Although several…

Computer Vision and Pattern Recognition · Computer Science 2023-06-09 Akash Awasthi , Son Ly , Jaer Nizam , Samira Zare , Videet Mehta , Safwan Ahmed , Keshav Shah , Ramakrishna Nemani , Saurabh Prasad , Hien Van Nguyen

We introduce a novel approach, a Dense Shell Method (DSM), for measuring distances for cosmology. It is based on original Baade idea to relate absolute difference of photospheric radii with photospheric velocity. We demonstrate that this…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Sergei Blinnikov , Marat Potashov , Petr Baklanov , Alexander Dolgov

In this study, we consider the application of orthogonality sampling method (OSM) with single and multiple sources for a fast identification of small objects in limited-aperture inverse scattering problem. We first apply the OSM with single…

Numerical Analysis · Mathematics 2026-05-08 Won-Kwang Park

Reconstruction-based methods have been commonly used for unsupervised anomaly detection, in which a normal image is reconstructed and compared with the given test image to detect and locate anomalies. Recently, diffusion models have shown…

Computer Vision and Pattern Recognition · Computer Science 2024-04-30 Di Wu , Shicai Fan , Xue Zhou , Li Yu , Yuzhong Deng , Jianxiao Zou , Baihong Lin

In this letter we study the subwavelength imaging of sparse broadband sources inside a disordered medium by processing the data acquired by a single antenna. A mathematical model has been developed for solving such problem based on the idea…

Optics · Physics 2015-06-18 Lianlin Li , Fang Li , Tie Jun Cui

We introduce a direct, linear sampling approach to imaging in an acoustic waveguide with sound hard walls. The waveguide terminates at one end and has unknown geometry due to compactly supported wall deformations. The goal of imaging is to…

Analysis of PDEs · Mathematics 2019-06-26 Liliana Borcea , Fioralba Cakoni , Shixu Meng