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Generalized alternating projections is an algorithm that alternates relaxed projections onto a finite number of sets to find a point in their intersection. We consider the special case of two linear subspaces, for which the algorithm…

Optimization and Control · Mathematics 2017-03-31 Mattias Fält , Pontus Giselsson

An alternating direction method of multipliers (ADMM) framework is developed for nonsmooth biconvex optimization for inverse problems in imaging. In particular, the simultaneous estimation of activity and attenuation (SAA) problem in…

Medical Physics · Physics 2024-02-13 Zhimei Ren , Emil Y. Sidky , Rina Foygel Barber , Chien-Min Kao , Xiaochuan Pan

In this paper we continue the study of good re-embeddings of affine K-algebras started in [KLR]. The idea is to use special linear projections to find isomorphisms between a given affine K-algebra K[X]/I, where X=(x_1,...,x_n), and…

Commutative Algebra · Mathematics 2022-07-18 Martin Kreuzer , Le Ngoc Long , Lorenzo Robbiano

Recent advances in computer vision take advantage of adversarial data augmentation to ameliorate the generalization ability of classification models. Here, we present an effective and efficient alternative that advocates adversarial…

Machine Learning · Computer Science 2021-03-24 Tianlong Chen , Yu Cheng , Zhe Gan , Jianfeng Wang , Lijuan Wang , Zhangyang Wang , Jingjing Liu

The image degradation produced by atmospheric turbulence and optical aberrations is usually alleviated using post-facto image reconstruction techniques, even when observing with adaptive optics systems. These techniques rely on the…

Instrumentation and Methods for Astrophysics · Physics 2015-05-18 A. Asensio Ramos , A. Lopez Ariste

In this paper we consider geometrical two-photon optics of Bessel-Gaussian modes generated in spontaneous parametric down-conversion of a Gaussian pump beam. We provide a general theoretical expression for the orbital angular momentum (OAM)…

Quantum Physics · Physics 2016-11-26 Melanie McLaren , Jacquiline Romero , Miles J. Padgett , Filippus S. Roux , Andrew Forbes

We derive normal approximation results for a class of stabilizing functionals of binomial or Poisson point process, that are not necessarily expressible as sums of certain score functions. Our approach is based on a flexible notion of the…

Probability · Mathematics 2022-10-20 Zhaoyang Shi , Krishnakumar Balasubramanian , Wolfgang Polonik

We propose a new parallel framework for fast computation of inverse and forward dynamics of articulated robots based on prefix sums (scans). We re-investigate the well-known recursive Newton-Euler formulation of robot dynamics and show that…

Robotics · Computer Science 2016-09-16 Yajue Yang , Yuanqing Wu , Jia Pan

We introduce the concept of compressed convolution, a technique to convolve a given data set with a large number of non-orthogonal kernels. In typical applications our technique drastically reduces the effective number of computations. The…

Instrumentation and Methods for Astrophysics · Physics 2014-01-08 F. Elsner , B. D. Wandelt

We study the multiorder coherent Raman scattering of a quantum probe field in a far-off-resonance medium with a prepared coherence. Under the conditions of negligible dispersion and limited bandwidth, we derive a Bessel-function solution…

Quantum Physics · Physics 2009-11-10 Fam Le Kien , Anil K. Patnaik , K. Hakuta

Many imaging technologies rely on tomographic reconstruction, which requires solving a multidimensional inverse problem given a finite number of projections. Backprojection is a popular class of algorithm for tomographic reconstruction,…

Image and Video Processing · Electrical Eng. & Systems 2020-06-03 Xueqing Liu , Paul Sajda

We describe many different realizations with integer coordinates for the associahedron (i.e. the Stasheff polytope) and for the cyclohedron (i.e. the Bott-Taubes polytope) and compare them to the permutahedron of type A_n and B_n…

Combinatorics · Mathematics 2011-12-20 Christophe Hohlweg , Carsten Lange

Enabled by x-ray free-electron lasers, nonlinear optical phenomena can be explored in the x-ray domain nowadays. Among the multitude of newly accessible processes, this theoretical study focuses parametric x-ray optical wavemixing for…

Optics · Physics 2021-04-14 Dietrich Krebs , Nina Rohringer

In this paper, we derive explicit reconstruction formulas for two common measurement geometries: a plane and a sphere. The problem is formulated as inverting the forward operator $R^a$, which maps the initial source to the measured wave…

Analysis of PDEs · Mathematics 2025-08-27 Cong Shi

Modern adaptive optics (AO) systems for large telescopes require tomographic techniques to reconstruct the phase aberrations induced by the turbulent atmosphere along a line of sight to a target which is angularly separated from the guide…

Instrumentation and Methods for Astrophysics · Physics 2015-06-03 James Osborn , Francisco Javier De Cos Juez , Dani Guzman , Timothy Butterley , Richard Myers , Andres Guesalaga , Jesus Laine

Low-noise phased arrays are essential for the next generation of microwave and submillimetre wave astronomy. We analyze their behaviour from a functional perspective, and show that their operation is intimately related to the mathematical…

Astrophysics · Physics 2007-07-12 S. Withington , G. Saklatvala , M. P. Hobson

Computing resonance and anti-resonance backbone curves in complex nonlinear mechanical systems is of high engineering relevance but remains computationally challenging, especially for large finite-element (FE) models. Existing…

Classical Physics · Physics 2026-02-09 Wei Wen , Weikai Qi , Weidong Wen

Meta-optics promises compact, high-performance imaging and color routing. However, designing high-performance structures is a high-dimensional optimization problem: mapping a desired optical output back to a physical 3D structure requires…

Machine Learning · Computer Science 2026-04-21 Chanik Kang , Hyewon Suk , Haejun Chung

In quantum electrodynamics, optical processes are theoretically described by double-sided Feynman diagrams. This formalism is powerful in the case of molecules but proves inappropriate to account for light-matter interactions within complex…

Optics · Physics 2019-06-10 T. Noblet , C. Humbert

Modern ground-based telescopes rely on a technology called adaptive optics (AO) in order to compensate for the loss of image quality caused by atmospheric turbulence. Next-generation AO systems designed for a wide field of view require a…

Numerical Analysis · Mathematics 2015-11-24 Tapio Helin , Stefan Kindermann , Daniela Saxenhuber