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This work presents a study of the interfacial dynamics of thin viscoelastic films subjected to the gravitational force and substrate interactions induced by the disjoining pressure, in two spatial dimensions. The governing equation is…

Fluid Dynamics · Physics 2022-04-12 Valeria Barra , Shahriar Afkhami , Lou Kondic

We study artifacts in the reconstruction of X-ray tomography due to nonlinear effects. For non-convex metal objects, we analyze the new phenomena of streak artifacts from inflection points on the boundary of metal objects. We characterize…

Analysis of PDEs · Mathematics 2021-09-15 Yiran Wang , Yuzhou Zou

In adversarial machine learning, there was a common belief that robustness and accuracy hurt each other. The belief was challenged by recent studies where we can maintain the robustness and improve the accuracy. However, the other…

Machine Learning · Computer Science 2021-06-01 Jingfeng Zhang , Jianing Zhu , Gang Niu , Bo Han , Masashi Sugiyama , Mohan Kankanhalli

A useful sampling-reconstruction model should be stable with respect to different kind of small perturbations, regardless whether they result from jitter, measurement errors, or simply from a small change in the model assumptions. In this…

General Mathematics · Mathematics 2007-05-31 E. costa-Reyes , A. Aldroubi , I. Krishtal

Predictive geometric models deliver excellent results for many Machine Learning use cases. Despite their undoubted performance, neural predictive algorithms can show unexpected degrees of instability and variance, particularly when applied…

Machine Learning · Computer Science 2018-07-20 Michaela Regneri , Malte Hoffmann , Jurij Kost , Niklas Pietsch , Timo Schulz , Sabine Stamm

The geodesic complexity of a Riemannian manifold is a numerical isometry invariant that is determined by the structure of its cut loci. In this article we study decompositions of cut loci over whose components the tangent cut loci fiber in…

Geometric Topology · Mathematics 2022-10-25 Stephan Mescher , Maximilian Stegemeyer

Tomographic image reconstruction with deep learning is an emerging field, but a recent landmark study reveals that several deep reconstruction networks are unstable for computed tomography (CT) and magnetic resonance imaging (MRI).…

Image and Video Processing · Electrical Eng. & Systems 2021-09-14 Weiwen Wu , Dianlin Hu , Wenxiang Cong , Hongming Shan , Shaoyu Wang , Chuang Niu , Pingkun Yan , Hengyong Yu , Varut Vardhanabhuti , Ge Wang

We discuss multiscale representations of discrete manifold-valued data. As it turns out that we cannot expect general manifold-analogues of biorthogonal wavelets to possess perfect reconstruction, we focus our attention on those…

Differential Geometry · Mathematics 2010-01-12 Philipp Grohs , Johannes Wallner

The inverse problem of backward diffusion is known to be ill-posed and highly unstable. Backward diffusion processes appear naturally in image enhancement and deblurring applications. It is therefore greatly desirable to establish a…

Numerical Analysis · Mathematics 2020-06-18 Leif Bergerhoff , Marcelo Cárdenas , Joachim Weickert , Martin Welk

We study the problem of recovering an unknown compactly-supported multivariate function from samples of its Fourier transform that are acquired nonuniformly, i.e. not necessarily on a uniform Cartesian grid. Reconstruction problems of this…

Numerical Analysis · Mathematics 2022-05-04 Ben Adcock , Milana Gataric , José Luis Romero

We show that while individual Riesz transforms are two weight norm stable under biLipschitz change of variables on $A_{\infty}$ weights, they are two weight norm unstable under even rotational change of variables on doubling weights. More…

Classical Analysis and ODEs · Mathematics 2024-06-13 Michel Alexis , José Luis Luna Garcia , Eric Sawyer , Ignacio Uriarte-Tuero

In this article, we study the properties of the geodesic X-ray transform for asymptotically Euclidean or conic Riemannian metrics and show injectivity under non-trapping and no conjugate point assumptions. We also define a notion of lens…

Differential Geometry · Mathematics 2021-02-09 Colin Guillarmou , Matti Lassas , Leo Tzou

In this paper, the local convergence of Iteratively regularized Landweber iteration method is investigated for solving non-linear inverse problems in Banach spaces. Our analysis mainly relies on the assumption that the inverse mapping…

Numerical Analysis · Mathematics 2020-11-17 Gaurav Mittal , Ankik Kumar Giri

The paper deals with a nonlinear evolution equation describing the dynamics of a non homogeneous multiply hinged beam, subject to a nonlocal restoring force of displacement type. First, a spectral analysis for the associated weighted…

Analysis of PDEs · Mathematics 2020-10-21 E. Berchio , A. Falocchi , M. Garrione

We show cocycle stability for linear maps with a weak irreducibility condition and their jointly integrable perturbations.

Dynamical Systems · Mathematics 2023-05-03 Ignacio Correa

We consider the boundary rigidity problem for asymptotically hyperbolic manifolds. We show injectivity of the X-ray transform in several cases and consider the non-linear inverse problem which consists of recovering a metric from boundary…

Differential Geometry · Mathematics 2017-09-18 C. Robin Graham , Colin Guillarmou , Plamen Stefanov , Gunther Uhlmann

We propose a family of gradient reconstruction schemes based on the solution of over-determined systems by orthogonal or oblique projections. In the case of orthogonal projections, we retrieve familiar weighted least-squares gradients, but…

In this paper we study the problem of photoacoustic inversion in a weakly attenuating medium. We present explicit reconstruction formulas in such media and show that the inversion based on such formulas is moderately ill--posed. Moreover,…

Numerical Analysis · Mathematics 2018-01-17 Otmar Scherzer , Cong Shi

This tutorial paper describes the problem of image reconstruction from interferometric data with a particular focus on the specific problems encountered at optical (visible/IR) wavelengths. The challenging issues in image reconstruction…

Instrumentation and Methods for Astrophysics · Physics 2011-04-20 Éric Thiébaut , Jean-François Giovannelli

The primary objective of this paper is to introduce Hyers-Ulam-type stability results for monotone, subadditive, and convex graphs. We consider their standard definitions in an approximate sense and demonstrate the existence of a…

General Mathematics · Mathematics 2026-02-05 Angshuman R. Goswami , Mahmood K. Shihab