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We study several numerical discretization techniques for the one-space plus one-time dimensional Dirac equation, including finite difference and space-time finite element methods. Two finite difference schemes and several space-time finite…

Numerical Analysis · Mathematics 2014-12-04 Robert Vaselaar , Hyun Lim , Jung-Han Kimn

Fractional calculus generalizes the derivative and antiderivative operations of differential and integral calculus from integer orders to the entire complex plane. Methods are presented for using this generalized calculus with Laplace…

Classical Analysis and ODEs · Mathematics 2007-05-23 F. S. Felber

Fine scale elastic structures are widespread in nature, for instances in plants or bones, whenever stiffness and low weight are required. These patterns frequently refine towards a Dirichlet boundary to ensure an effective load transfer.…

Numerical Analysis · Mathematics 2017-11-13 Nora Lüthen , Martin Rumpf , Sascha Tölkes , Orestis Vantzos

Segmentation plays an important role in many preprocessing stages in image processing. Recently, convex relaxation methods for image multi-labeling were proposed in the literature. Often these models involve the total variation (TV)…

Numerical Analysis · Mathematics 2012-05-17 S. Häuser , G. Steidl

Motivated by many applications in complex domains with boundaries exposed to large topological changes or deformations, fictitious domain methods regard the actual domain of interest as being embedded in a fixed Cartesian background. This…

Numerical Analysis · Mathematics 2020-03-17 Georgios Katsouleas , Efthymios N. Karatzas , Fotios Travlopanos

Discrete differential geometry aims to develop discrete equivalents of the geometric notions and methods of classical differential geometry. In this survey we discuss the following two fundamental Discretization Principles: the…

Differential Geometry · Mathematics 2015-06-26 Alexander I. Bobenko , Yuri B. Suris

We equip a family of algebras whose noncommutativity is of Lie type with a derivation based differential calculus obtained, upon suitably using both inner and outer derivations, as a reduction of a redundant calculus over the Moyal four…

Quantum Algebra · Mathematics 2018-12-26 Giuseppe Marmo , Patrizia Vitale , Alessandro Zampini

In this paper, we develop regularized discrete least squares collocation and finite volume methods for solving two-dimensional nonlinear time-dependent partial differential equations on irregular domains. The solution is approximated using…

Numerical Analysis · Mathematics 2019-06-26 Fanhai Zeng , Ian Turner , Kevin Burrage , Stephen J. Wright

Many image processing problems are naturally expressed as energy minimization or shape optimization problems, in which the free variable is a shape, such as a curve in 2d or a surface in 3d. Examples are image segmentation, multiview stereo…

Optimization and Control · Mathematics 2013-07-23 Günay Doğan

Shape inference is classically ill-posed, because it involves a map from the (2D) image domain to the (3D) world. Standard approaches regularize this problem by either assuming a prior on lighting and rendering or restricting the domain,…

Computer Vision and Pattern Recognition · Computer Science 2020-08-21 Steven W Zucker

Triangle meshes remain the most popular data representation for surface geometry. This ubiquitous representation is essentially a hybrid one that decouples continuous vertex locations from the discrete topological triangulation.…

Computer Vision and Pattern Recognition · Computer Science 2021-09-23 Marie-Julie Rakotosaona , Noam Aigerman , Niloy Mitra , Maks Ovsjanikov , Paul Guerrero

This paper is concerned with a shape sensitivity analysis of a viscous incompressible fluid driven by Stokes equations with nonhomogeneous boundary condition. The structure of shape gradient with respect to the shape of the variable domain…

Optimization and Control · Mathematics 2007-05-23 Z. M. Gao , Y. C. Ma , H. W. Zhuang

We introduce an original approach to geometric calculus in which we define derivatives and integrals on functions which depend on extended bodies in space--that is, paths, surfaces, and volumes etc. Though this theory remains to be fully…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Theodore G. Erler

We examine the use of domain decomposition for potentially more efficient mean curvature flow of surface meshes, whose faces are arbitrary simple polygons. We first test traditional domain decomposition methods with and without overlap of…

Numerical Analysis · Mathematics 2026-05-13 Lenka Ptackova , Michal Outrata

A Frontal-Delaunay refinement algorithm for mesh generation in piecewise smooth domains is described. Built using a restricted Delaunay framework, this new algorithm combines a number of novel features, including: (i) an unweighted,…

Computational Geometry · Computer Science 2016-07-27 Darren Engwirda

This study proposes an end-to-end unsupervised diffeomorphic deformable registration framework based on moving mesh parameterization. Using this parameterization, a deformation field can be modeled with its transformation Jacobian…

Image and Video Processing · Electrical Eng. & Systems 2022-08-30 Ameneh Sheikhjafari , Deepa Krishnaswamy , Michelle Noga , Nilanjan Ray , Kumaradevan Punithakumar

We study the convergence of the new family of mimetic finite difference schemes for linear diffusion problems recently proposed in [38]. In contrast to the conventional approach, the diffusion coefficient enters both the primary mimetic…

Numerical Analysis · Mathematics 2016-12-07 G. Manzini , K. Lipnikov , J. D. Moulton , M. Shashkov

This paper proposes the estimation of a mutual shape from a set of different segmentation results using both active contours and information theory. The mutual shape is here defined as a consensus shape estimated from a set of different…

Image and Video Processing · Electrical Eng. & Systems 2021-02-18 S. Jehan-Besson , R. Clouard , C. Tilmant , A. de Cesare , A. Lalande , J. Lebenberg , P. Clarysse , L. Sarry , F. Frouin , M. Garreau

Image classifiers are known to be difficult to interpret and therefore require explanation methods to understand their decisions. We present ShearletX, a novel mask explanation method for image classifiers based on the shearlet transform --…

Computer Vision and Pattern Recognition · Computer Science 2023-05-01 Stefan Kolek , Robert Windesheim , Hector Andrade Loarca , Gitta Kutyniok , Ron Levie

We consider general shape optimization problems governed by Dirichlet boundary value problems. The proposed approach may be extended to other boundary conditions as well. It is based on a recent representation result for implicitly defined…

Optimization and Control · Mathematics 2020-03-27 Cornel Marius Murea , Dan Tiba