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The paper presents a two-dimensional geometrically nonlinear formulation of a beam element that can accommodate arbitrarily large rotations of cross sections. The formulation is based on the integrated form of equilibrium equations, which…

Numerical Analysis · Mathematics 2021-04-20 Milan Jirásek , Emma La Malfa Ribolla , Martin Horák

We present novel, exotic types of frame changes for the calculation of quantum evolution operators. We detail in particular the biframe, in which a physical system's evolution is seen in an equal mixture of two different standard frames at…

Quantum Physics · Physics 2025-10-07 Pierre-Louis Giscard , Omid Faizy , Christian Bonhomme

We present a new method for computing orbits in the perturbed two-body problem: the position and velocity vectors of the propagated object in Cartesian coordinates are replaced by eight orbital elements, i.e., constants of the unperturbed…

Classical Physics · Physics 2020-03-11 Giulio Baù , Javier Roa

In this work, we propose a generalized alternating Anderson acceleration method, a periodic scheme composed of $t$ fixed-point iteration steps, interleaved with $s$ steps of Anderson acceleration with window size $m$, to solve linear and…

Numerical Analysis · Mathematics 2026-02-02 Yunhui He , Santolo Leveque

The aim of this paper is to discuss and evaluate total variation based regularization methods for motion estimation, with particular focus on optical flow models. In addition to standard $L^2$ and $L^1$ data fidelities we give an overview…

Numerical Analysis · Mathematics 2015-12-02 Martin Burger , Hendrik Dirks , Lena Frerking

This article presents and compares four approaches for computing the rotation of a point about an axis by an angle in $\mathbb{R}^3$. We illustrate these methods by computing, by hand, the rotation of point $P=(1,0,1)^T$ about axis…

Metric Geometry · Mathematics 2025-04-08 Tom Verhoeff

The computation of 2-D optical flow by means of regularized pel-recursive algorithms raises a host of issues, which include the treatment of outliers, motion discontinuities and occlusion among other problems. We propose a new approach…

Computer Vision and Pattern Recognition · Computer Science 2016-11-07 Vania V. Estrela , Luis A. Rivera , Paulo C. Beggio , Ricardo T. Lopes

We present a Newton-like method to solve inverse problems and to quantify parameter uncertainties. We apply the method to parameter reconstruction in optical scatterometry, where we take into account a priori information and measurement…

Computational Physics · Physics 2017-07-27 M. Hammerschmidt , M. Weiser , X. Garcia Santiago , L. Zschiedrich , B. Bodermann , S. Burger

We present a method for constructing all bounded rational motions that frame a space curve $\mathbf{r}(t)$. This means that the motion guides an orthogonal frame along the curve such that one frame axis is in direction of the curve tangent.…

Optimization and Control · Mathematics 2025-08-04 Hans-Peter Schröcker , Zbyněk Šír

In this paper, we aim to accelerate a preconditioned alternating direction method of multipliers (pADMM), whose proximal terms are convex quadratic functions, for solving linearly constrained convex optimization problems. To achieve this,…

Optimization and Control · Mathematics 2024-12-10 Defeng Sun , Yancheng Yuan , Guojun Zhang , Xinyuan Zhao

A singularly perturbed linear system of second order ordinary differential equations of reaction-diffusion type with given boundary conditions is considered. The leading term of each equation is multiplied by a small positive parameter.…

Numerical Analysis · Mathematics 2009-06-23 M. Paramasivam , S. Valarmathi , J. J. H. Miller

We study quantum radiation generated by an accelerated motion of a small body with a refractive index n which differes slightly from 1. To simplify calculations we consider a model with a scalar massless field. We use the perturbation…

General Relativity and Quantum Cosmology · Physics 2011-07-19 V. Frolov , D. Singh

In decision theoretic estimation of parameters in Euclidean space $\mathbb{R}^p$, the action space is chosen to be the convex closure of the estimand space. In this paper, the concept has been extended to the estimation of circular…

Statistics Theory · Mathematics 2016-06-28 Kanika , Somesh Kumar

It is believed that some numerical technique must be employed for the determination of the system parameters of a visual binary or a star with a planet because the relevant equations are not only highly nonlinear but also transcendental…

Astrophysics · Physics 2015-06-24 Hideki Asada , Toshio Akasaka , Masumi Kasai

Convenient parameterizations of matrices in terms of vectors transform (certain classes of) matrix equations into covariant (hence rotation-invariant) vector equations. Certain recently introduced such parameterizations are tersely…

Exactly Solvable and Integrable Systems · Physics 2009-11-10 M. Bruschi , F. Calogero

The relativistic acceleration of an electron in a uniform gravitational field is calculated numerically using the generalization of the Dirac equation to curved spacetime. Equivalent results are also obtained analytically using an iterative…

General Relativity and Quantum Cosmology · Physics 2016-02-09 J. D. Franson

Estimating optical flows is one of the most interesting problems in computer vision, which estimates the essential information about pixel-wise displacements between two consecutive images. This work introduces an efficient dual…

Optimization and Control · Mathematics 2021-10-05 Hongpeng Sun , Xue-Cheng Tai , Jing Yuan

The problems of optimally estimating a phase, a direction, and the orientation of a Cartesian frame (or trihedron) with general pure states are addressed. Special emphasis is put on estimation schemes that allow for inconclusive answers or…

Quantum Physics · Physics 2013-08-09 B. Gendra , E. Ronco-Bonvehi , J. Calsamiglia , R. Muñoz-Tapia , E. Bagan

The alternating direction method of multipliers (ADMM) has emerged as a powerful technique for large-scale structured optimization. Despite many recent results on the convergence properties of ADMM, a quantitative characterization of the…

Optimization and Control · Mathematics 2016-11-17 Euhanna Ghadimi , André Teixeira , Iman Shames , Mikael Johansson

Beam tracking software for accelerators typically falls into two categories: fast envelope simulations limited to linear beam optics, and slower multiparticle simulations that can model nonlinear effects. To find a middle ground between…

Accelerator Physics · Physics 2017-08-02 Ben Folsom , Emanuele Laface