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In this paper we study the inverse Laplace transform. We first derive a new global logarithmic stability estimate that shows that the inversion is severely ill-posed. Then we propose a regularization method to compute the inverse Laplace…

Analysis of PDEs · Mathematics 2023-04-18 Pierre Maréchal , Faouzi Triki , Walter C. Simo Tao Lee

Here we discuss a regularized version of the factorization method for positive operators acting on a Hilbert Space. The factorization method is a qualitative reconstruction method that has been used to solve many inverse shape problems. In…

Analysis of PDEs · Mathematics 2022-04-11 Isaac Harris

Volterra series are especially useful for nonlinear system identification, also thanks to their capability to approximate a broad range of input-output maps. However, their identification from a finite set of data is hard, due to the curse…

Machine Learning · Computer Science 2019-11-13 Alberto Dalla Libera , Ruggero Carli , Gianluigi Pillonetto

We present a novel approach for the inverse problem in electrical impedance tomography based on regularized quadratic regression. Our contribution introduces a new formulation for the forward model in the form of a nonlinear integral…

Geophysics · Physics 2012-05-29 Nick Polydorides , Alireza Aghasi , Eric L. Miller

A vortex is intuitively recognized as the rotational/swirling motion of the fluids. However, an unambiguous and universally-accepted definition for vortex is yet to be achieved in the field of fluid mechanics, which is probably one of the…

Fluid Dynamics · Physics 2018-04-18 Chaoqun Liu , Yisheng Gao , Shuling Tian , Xiangrui Dong

Optimization techniques have been widely used in deformable registration, allowing for the incorporation of similarity metrics with regularization mechanisms. These regularization mechanisms are designed to mitigate the effects of trivial…

Computer Vision and Pattern Recognition · Computer Science 2014-04-10 Martin Rajchl , John S. H. Baxter , Wu Qiu , Ali R. Khan , Aaron Fenster , Terry M. Peters , Jing Yuan

We have performed normalization of Hamiltonian in the generalized photogravitational restricted three body problem with Poynting-Robertson drag. In this problem we have taken bigger primary as source of radiation and smaller primary as an…

Dynamical Systems · Mathematics 2007-09-27 B. S. Kushvah , J. P. Sharma , B. Ishwar

We consider a strongly heterogeneous medium saturated by an incompressible viscous fluid as it appears in geomechanical modeling. This poroelasticity problem suffers from rapidly oscillating material parameters, which calls for a thorough…

Numerical Analysis · Mathematics 2018-12-27 Robert Altmann , Eric Chung , Roland Maier , Daniel Peterseim , Sai-Mang Pun

Techniques are developed here for evaluating the r-modes of rotating neutron stars through second order in the angular velocity of the star. Second-order corrections to the frequencies and eigenfunctions for these modes are evaluated for…

General Relativity and Quantum Cosmology · Physics 2016-08-25 Lee Lindblom , Gregory Mendell , Benjamin J. Owen

Shape based classification is one of the most challenging tasks in the field of computer vision. Shapes play a vital role in object recognition. The basic shapes in an image can occur in varying scale, position and orientation. And…

Computer Vision and Pattern Recognition · Computer Science 2013-07-23 Subra Mukherjee , Karen Das

We present an accurate Lagrangian method based on vortex particles, level-sets, and immersed boundary methods, for animating the interplay between two fluids and rigid solids. We show that a vortex method is a good choice for simulating…

Numerical Analysis · Mathematics 2016-08-16 Mathieu Coquerelle , Jérémie Allard , Georges-Henri Cottet , Marie-Paule Cani

The Lagrange-mesh method is an approximate variational approach having the form of a mesh calculation because of the use of a Gauss quadrature. Although this method provides accurate results in many problems with small number of mesh…

Quantum Physics · Physics 2016-10-05 Jérémy Dohet-Eraly

The problem of stabilization of unstable periodic orbits of discrete nonlinear systems is considered in the article. A new generalization of the delayed feedback, which solves the stabilization problem, is proposed. The feedback is…

Chaotic Dynamics · Physics 2017-10-02 D. Dmitrishin , A. Stokolos , I. Skrynnik , E. Franzheva

Triangular meshes are the most popular representations of 3D objects, but many mesh surfaces contain topological singularities that represent a challenge for displaying or further processing them properly. One such singularity is the…

Computational Geometry · Computer Science 2022-06-22 K. Sfikas , P. Perakis , T. Theoharis

We study the quantum improvement of Kerr black holes with mass-dependent scale identifications in asymptotically safe gravity. We find that a physically sensible identification can only be a function of $Mr$ and the area $A=4\pi(r^2+a^2)$…

High Energy Physics - Theory · Physics 2024-10-11 Chiang-Mei Chen , Yi Chen , Akihiro Ishibashi , Nobuyoshi Ohta

This paper focuses on regularisation methods using models up to the third order to search for up to second-order critical points of a finite-sum minimisation problem. The variant presented belongs to the framework of [3]: it employs random…

Numerical Analysis · Mathematics 2021-04-05 Stefania Bellavia , Gianmarco Gurioli , Benedetta Morini , Philippe L. Toint

This paper focuses on recovering an unknown vector $\beta$ from the noisy data $Y=X\beta +\sigma\xi$, where $X$ is a known $n\times p$-matrix, $\xi $ is a standard white Gaussian noise, and $\sigma$ is an unknown noise level. In order to…

Statistics Theory · Mathematics 2011-12-30 Yuri Golubev

A method to treat frictional contact problems along embedded surfaces in the finite element framework is developed. Arbitrarily shaped embedded surfaces, cutting through finite element meshes, are handled by the X-FEM. The frictional…

Computational Engineering, Finance, and Science · Computer Science 2019-02-12 Basava Raju Akula , Julien Vignollet , Vladislav A. Yastrebov

Regularising the primal formulation of optimal transport (OT) with a strictly convex term leads to enhanced numerical complexity and a denser transport plan. Many formulations impose a global constraint on the transport plan, for instance…

Machine Learning · Computer Science 2023-10-05 Hugues Van Assel , Titouan Vayer , Remi Flamary , Nicolas Courty

A regularization procedure developed in [1] for the integral curvature invariants on manifolds with conical singularities is generalized to the case of squashed cones. In general, the squashed conical singularities do not have rotational…

High Energy Physics - Theory · Physics 2015-06-16 Dmitri V. Fursaev , Alexander Patrushev , Sergey N. Solodukhin