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Inverse problems are prevalent in numerous scientific and engineering disciplines, where the objective is to determine unknown parameters within a physical system using indirect measurements or observations. The inherent challenge lies in…

Computational Physics · Physics 2025-02-06 Georgios E. Pavlou , Vasiliki Pavlidou , Vagelis Harmandaris

[abridge]Cosmic velocity and tidal fields are important for the understanding of the cosmic web and the environments of galaxies, and can also be used to constrain cosmology. In this paper, we reconstruct these two fields in SDSS volume…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Huiyuan Wang , H. J. Mo , Xiaohu Yang , Frank C. van den Bosch

A valuable amount of information is available in peculiar velocities of galaxies. Peculiar velocity surveys have recently allowed the discovery of potential problems with LCDM. Nonetheless, their direct observation through distance…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 G. Lavaux

Variational Bayes (VB) has become a widely-used tool for Bayesian inference in statistics and machine learning. Nonetheless, the development of the existing VB algorithms is so far generally restricted to the case where the variational…

Machine Learning · Computer Science 2021-08-04 Minh-Ngoc Tran , Dang H. Nguyen , Duy Nguyen

We present a self-consistent Bayesian formalism to sample the primordial density fields compatible with a set of dark matter density tracers after cosmic evolution observed in redshift space. Previous works on density reconstruction did not…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-09 E. G. Patrick Bos , Francisco-Shu Kitaura , Rien van de Weygaert

The simulation of physical phenomena with computer models relies on the estimation of physical and/or numerical parameters calibrated to fit experimental data. The approximations within the computer model and the errors in the measurements…

Methodology · Statistics 2026-05-12 Paul Lartaud , Gwenaël Salin

The reconstruction of the peculiar velocity field from the 1.936~Jy iras selected sample of galaxies is compared to a similar reconstruction from an optically selected sample. A general method for combining different samples to reconstruct…

Astrophysics · Physics 2015-06-24 Wolfram Freudling , Luiz Nicolaci da Costa , Paulo S. Pellegrini

We present the reconstructed real-space density and the predicted velocity fields from the Two Mass Redshift Survey (2MRS). The 2MRS is the densest all-sky redshift survey to date and includes about 23,200 galaxies with extinction corrected…

We derive peculiar velocities for the 6dF Galaxy Survey (6dFGS) and describe the velocity field of the nearby ($z<0.055$) southern hemisphere. The survey comprises 8885 galaxies for which we have previously reported Fundamental Plane data.…

Characterizing statistical properties of solutions of inverse problems is essential for decision making. Bayesian inversion offers a tractable framework for this purpose, but current approaches are computationally unfeasible for most…

Machine Learning · Statistics 2024-12-18 Jonas Adler , Ozan Öktem

We present a new framework for estimating a galaxy's gravitational potential, Phi(x), from its stellar kinematics by adopting a fully non-parametric model for the galaxy's unknown action-space distribution function, f(J). Having an…

Astrophysics of Galaxies · Physics 2015-06-15 John Magorrian

We introduce BAYES-LOSVD, a novel implementation of the non-parametric extraction of line-of-sight velocity distributions (LOSVDs) in galaxies. We employ bayesian inference to obtain robust LOSVDs and associated uncertainties. Our method…

Astrophysics of Galaxies · Physics 2021-02-03 J. Falcon-Barroso , M. Martig

Modelling noise in gravitational-wave observatories is crucial for accurately inferring the properties of gravitational-wave sources. We introduce a transdimensional Bayesian approach to characterise the noise in ground-based…

Instrumentation and Methods for Astrophysics · Physics 2025-03-10 Nir Guttman , Paul D. Lasky , Eric Thrane

Using the Tully-Fisher relation, we derive peculiar velocities for the 2MASS Tully-Fisher Survey and describe the velocity field of the nearby Universe. We use adaptive kernel smoothing to map the velocity field, and compare it to…

This paper addresses the challenge of fine-grained alignment in Vision-and-Language Navigation (VLN) tasks, where robots navigate realistic 3D environments based on natural language instructions. Current approaches use contrastive learning…

Computer Vision and Pattern Recognition · Computer Science 2024-12-03 Yuhang Song , Mario Gianni , Chenguang Yang , Kunyang Lin , Te-Chuan Chiu , Anh Nguyen , Chun-Yi Lee

The local galaxy peculiar velocity field can be reconstructed from the surrounding distribution of large-scale structure and plays an important role in calibrating cosmic growth and expansion measurements. In this paper, we investigate the…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-20 Ryan J. Turner , Chris Blake

We solve a Bayesian inverse Navier-Stokes (N-S) problem that assimilates velocimetry data in order to jointly reconstruct the flow field and learn the unknown N-S parameters. By incorporating a Carreau shear-thinning viscosity model into…

Fluid Dynamics · Physics 2025-05-21 Alexandros Kontogiannis , Richard Hodgkinson , Emily L. Manchester

Cosmological probes pose an inverse problem where the measurement result is obtained through observations, and the objective is to infer values of model parameters which characterize the underlying physical system -- our Universe. Modern…

Instrumentation and Methods for Astrophysics · Physics 2019-05-21 Timur Takhtaganov , Zarija Lukic , Juliane Mueller , Dmitriy Morozov

Future urban transportation concepts include a mixture of ground and air vehicles with varying degrees of autonomy in a congested environment. In such dynamic environments, occupancy maps alone are not sufficient for safe path planning.…

Robotics · Computer Science 2021-07-26 Ransalu Senanayake , Kyle Beltran Hatch , Jason Zheng , Mykel J. Kochenderfer

The problem of the reconstruction of the large scale density and velocity fields from peculiar velocities surveys is addressed here within a Bayesian framework by means of Hamiltonian Monte Carlo (HMC) sampling. The HAmiltonian Monte carlo…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-01 Aurélien Valade , Yehuda Hoffman , Noam I Libeskind , Romain Graziani
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