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Recent Lyman-$\alpha$ forest tomography measurements of the intergalactic medium (IGM) have revealed a wealth of cosmic structures at high redshift ($z\sim 2.5$). In this work, we present the Tomographic Absorption Reconstruction and…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-18 Benjamin Horowitz , Khee-Gan Lee , Martin White , Alex Krolewski , Metin Ata

Compressed sensing (CS) is an innovative technique allowing to represent signals through a small number of their linear projections. In this paper we address the application of CS to the scenario of progressive acquisition of 2D visual…

Information Theory · Computer Science 2014-03-06 Giulio Coluccia , Enrico Magli

In [L. Chen and R. Li, Journal of Scientific Computing, Vol. 68, pp. 1172--1197, (2016)], an integrated linear reconstruction was proposed for finite volume methods on unstructured grids. However, the geometric hypothesis of the mesh to…

Numerical Analysis · Mathematics 2018-04-24 Li Chen , Guanghui Hu , Ruo Li

In previous works we proposed the Reverse Zeldovich Approximation (RZA) method, which can be used to estimate the cosmological initial conditions underlying the galaxy distribution in the Local Universe using peculiar velocity data. In this…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Timur Doumler , Stefan Gottloeber , Yehuda Hoffman , Helene Courtois

Scaled relative graphs (SRGs) enable graphical analysis and design of nonlinear systems. In this paper, we present a systematic approach for computing both soft and hard SRGs of nonlinear systems using dynamic integral quadratic constraints…

Optimization and Control · Mathematics 2026-04-03 Timo de Groot , Tom Oomen , W. P. M. H. Heemels , Sebastiaan van den Eijnden

We use the formalism of constrained Gaussian random field to compute a precise large scale simulation of the 60 Mpc/h volume of our Local Universe. We derive the constraints from the reconstructed peculiar velocities of the 2MASS Redshift…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Guilhem Lavaux

The problem of finding suitable point embedding or geometric configurations given only Euclidean distance information of point pairs arises both as a core task and as a sub-problem in a variety of machine learning applications. In this…

Machine Learning · Computer Science 2024-10-23 Ipsita Ghosh , Abiy Tasissa , Christian Kümmerle

We present a new analytic approach to describe large scale structure formation in the mildly non-linear regime. The central object of the method is the time-dependent probability distribution function generating correlators of the…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-09 Diego Blas , Mathias Garny , Mikhail M. Ivanov , Sergey Sibiryakov

This thesis investigates algorithms regarding their applicability for highly nonlinear model fitting on big datasets. Various mathematical methods are presented with which a model fit using the least squares criterion is possible. Special…

Instrumentation and Methods for Astrophysics · Physics 2017-12-20 Robin Geyer

We introduce a novel data-driven order reduction method for nonlinear control systems, drawing on recent progress in machine learning and statistical dimensionality reduction. The method rests on the assumption that the nonlinear system…

Optimization and Control · Mathematics 2011-06-15 Jake Bouvrie , Boumediene Hamzi

The Nonlinear GMRES (NGMRES) proposed by Washio and Oosterlee [Electron. Trans. Numer. Anal, 6(271-290), 1997] is an acceleration method for fixed point iterations. It has been demonstrated to be effective, but its convergence properties…

Numerical Analysis · Mathematics 2026-02-11 Chen Greif , Yunhui He

Compressive sensing is a methodology for the reconstruction of sparse or compressible signals using far fewer samples than required by the Nyquist criterion. However, many of the results in compressive sensing concern random sampling…

Information Theory · Computer Science 2013-06-11 Atul Divekar , Deanna Needell

The Vietoris-Rips filtration is a versatile tool in topological data analysis. It is a sequence of simplicial complexes built on a metric space to add topological structure to an otherwise disconnected set of points. It is widely used…

Computational Geometry · Computer Science 2013-03-07 Donald R. Sheehy

We present a neural-field-based large-scale reconstruction system that fuses lidar and vision data to generate high-quality reconstructions that are geometrically accurate and capture photo-realistic textures. This system adapts the…

Robotics · Computer Science 2025-02-18 Yifu Tao , Yash Bhalgat , Lanke Frank Tarimo Fu , Matias Mattamala , Nived Chebrolu , Maurice Fallon

We assess a neural network (NN) method for reconstructing 3D cosmological density and velocity fields (target) from discrete and incomplete galaxy distributions (input). We employ second-order Lagrangian Perturbation Theory to generate a…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-02 Punyakoti Ganeshaiah Veena , Robert Lilow , Adi Nusser

We revisit the issue of non-parametric gravitational lens reconstruction and present a new method to obtain the cluster mass distribution using strong lensing data without using any prior information on the underlying mass. The method…

Astrophysics · Physics 2009-10-07 J. M. Diego , P. Protopapas , H. B Sandvik , M. Tegmark

In practical nonlinear filtering, the assessment of achievable filtering performance is important. In this paper, we focus on the problem of efficiently approximate the posterior Cramer-Rao lower bound (CRLB) in a recursive manner. By using…

Applications · Statistics 2010-05-31 Ming Lei , Pierre Del Moral , Christophe Baehr

We consider the problem of efficiently solving large-scale linear least squares problems that have one or more linear constraints that must be satisfied exactly. Whilst some classical approaches are theoretically well founded, they can face…

Numerical Analysis · Mathematics 2021-12-24 Jennifer Scott , Miroslav Tuma

We present a grism extraction package (LINEAR) designed to reconstruct one-dimensional spectra from a collection of slitless spectroscopic images, ideally taken at a variety of orientations, dispersion directions, and/or dither positions.…

Instrumentation and Methods for Astrophysics · Physics 2018-02-21 R. E. Ryan , S. Casertano , N. Pirzkal

We develop a new method to constraint primordial non-Gaussianities of the local kind using unclustered tracers of the Large Scale Structure. We show that in the limit of low noise, zero bias tracers yield large improvement over standard…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-12 Emanuele Castorina , Yu Feng , Uros Seljak , Francisco Villaescusa-Navarro