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We address the problem of improving the performance and in particular the sample complexity of deep neural networks by enforcing and guaranteeing invariances to symmetry transformations rather than learning them from data. Group-equivariant…

Machine Learning · Computer Science 2023-03-06 Matthias Rath , Alexandru Paul Condurache

The ambipolar-diffusion theory of star formation predicts the formation of fragments in molecular clouds with mass-to-flux ratios greater than that of the parent-cloud envelope. By contrast, scenarios of turbulence-induced fragmentation do…

Astrophysics of Galaxies · Physics 2015-05-14 Telemachos Ch. Mouschovias , Konstantinos Tassis

Spatiotemporal properties of two-dimensional (2D) Hall-magnetohydrodynamic turbulence at intermediate plasma $\beta=2$ are studied by means of Fast Iterative Filtering, a new technique for the decomposition of nonstationary nonlinear…

A novel approach is presented in this paper to improve images which are altered by atmospheric turbulence. Two new algorithms are presented based on two combinations of a blind deconvolution block, an elastic registration block and a…

Computer Vision and Pattern Recognition · Computer Science 2024-11-13 Jerome Gilles , Tristan Dagobert , Carlo De Franchis

In this paper we focus on the empirical variable-selection peformance of subsample-ordered least angle regression (Solar) -- a novel ultrahigh dimensional redesign of lasso -- on the empirical data with complicated dependence structures…

Machine Learning · Statistics 2020-12-17 Ning Xu , Timothy C. G. Fisher , Jian Hong

We introduce a novel way to extract information from turbulent datasets by applying an ARMA statistical analysis. Such analysis goes well beyond the analysis of the mean flow and of the fluctuations and links the behavior of the recorded…

We present a new method of wavelet packet decomposition to be used in gravitational wave detection. An issue in wavelet analysis is what is the time-frequency resolution which is best suited to analyze data when in quest of a signal of…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Riccardo Sturani , Roberto Terenzi

This paper focuses on waveform design for joint radar and communication systems and presents a new subset selection process to improve the communication error rate performance and global accuracy of radar sensing of the random stepped…

Information Theory · Computer Science 2024-01-17 Shalanika Dayarathna , Rajitha Senanayake , Peter Smith , Jamie Evans

We present a new algorithm for identifying dark matter halos, substructure, and tidal features. The approach is based on adaptive hierarchical refinement of friends-of-friends groups in six phase-space dimensions and one time dimension,…

Cosmology and Nongalactic Astrophysics · Physics 2013-01-15 Peter S. Behroozi , Risa H. Wechsler , Hao-Yi Wu

The geometric design of structures with optimized physical and chemical properties is one of the core topics in materials science. However, designing new functional materials is challenging due to the vast number of existing and the…

Optics · Physics 2025-07-17 Congcong Cui , Guangfeng Wei , Matthias Saba , Yuanyuan Cao , Lu Han

We present new experimental results on the development of turbulent spots in channel flow. The internal structure of a turbulent spot is measured, with Time Resolved Stereoscopic Particle Image Velocimetry. We report the observation of…

Fluid Dynamics · Physics 2013-11-20 Grégoire Lemoult , Konrad Gumowski , Jean-Luc Aider , José Eduardo Wesfreid

Wave breaking injects turbulence and bubbles into the upper ocean, modulating air-sea exchange of momentum, heat, gases, and sea-spray aerosols. These fluxes depend nonlinearly on sea state but remain poorly represented in coupled…

Atmospheric and Oceanic Physics · Physics 2026-02-05 Xiaohui Zhou , Anton S. Darmenov , Kianoosh Yousefi

A set of semi-analytical techniques based on Fourier analysis is used to solve wave scattering problems in variously shaped waveguides with varying normal admittance boundary conditions. Key components are newly developed conformal mapping…

Mathematical Physics · Physics 2015-06-02 Anders Andersson , Borje Nilsson , Thomas Biro

The estimation of power spectra from LDA data provides signal processing challenges for fluid dynamicists for several reasons: acquisition is dictated by randomly arriving particles, the registered particle velocities tend to be biased…

Fluid Dynamics · Physics 2019-06-14 Clara M. Velte , William K. George , Preben Buchhave

Global intermittency is observed in the stably stratified Atmospheric Boundary Layer (ABL) and corresponds to having large nonturbulent flow regions to develop in an otherwise turbulent flow. In this paper, the differences between…

Fluid Dynamics · Physics 2021-11-17 Abhishek Harikrishnan , Cedrick Ansorge , Rupert Klein , Nikki Vercauteren

The feature based spatial verification method SAL is applied to cloud data, i.e. two-dimensional spatial fields of total cloud cover and spectral radiance. Model output is obtained from the COSMO-DE forward operator SynSat and compared to…

Atmospheric and Oceanic Physics · Physics 2016-03-08 Michael Weniger , Petra Friederichs

We explore the structure and statistics of multiphase, magnetized ISM turbulence in the local Milky Way by means of driven periodic box numerical MHD simulations. Using the higher order-accurate piecewise-parabolic method on a local stencil…

Astrophysics of Galaxies · Physics 2017-06-19 Alexei G. Kritsuk , Sergey D. Ustyugov , Michael L. Norman

We introduce an innovative wavelet-based approach to dynamically adjust the local grid resolution to maintain a uniform specified error tolerance. Extending the work of Dubos and Kevlahan (2013), a wavelet multi-scale approximation is used…

Geophysics · Physics 2015-10-28 Matthias Aechtner , Nicholas Kevlahan , Thomas Dubos

Guided by the duality of turbulence (random versus coherent we seek coherent structures in the turbulent velocity field of molecular clouds, anticipating their importance in cloud evolution. We analyse a large map (40' by 20') obtained with…

Astrophysics of Galaxies · Physics 2015-05-13 Pierre Hily-Blant , Edith Falgarone

Scale invariance (fractality) is a prominent feature of the large-scale behavior of many stochastic systems. In this work, we construct an algorithm for the statistical identification of the Hurst distribution (in particular, the scaling…

Methodology · Statistics 2025-01-31 Patrice Abry , Gustavo Didier , Oliver Orejola , Herwig Wendt