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Context: Telescopes like the Extremely Large Telescope (ELT) and the Giant Magellan Telescope (GMT) will be used together with extreme adaptive optics (AO) instruments to directly image Earth-like planets. The AO systems will need to…

Instrumentation and Methods for Astrophysics · Physics 2024-01-17 Sebastiaan Y. Haffert

GPR full-waveform inversion optimizes the subsurface property model iteratively to match the entire waveform information. However, the model gradients derived from wavefield continuation often contain errors, such as ghost values and…

For ExAO instruments for the Giant Segmented Mirror Telescopes (GSMTs), alternative architectures of WFS are under consideration because there is a tradeoff between detector size, speed, and noise that reduces the performance of GSMT-ExAO…

We propose a new type of Wave Front Sensor (WFS) derived from the Pyramid WFS (PWFS). This new WFS, called the Flattened Pyramid-WFS (FPWFS), has a reduced Pyramid angle in order to optically overlap the four pupil images into an unique…

Instrumentation and Methods for Astrophysics · Physics 2015-08-06 O. Fauvarque , B. Neichel , T. Fusco , J. F. Sauvage

There exists continuous demand of improved turbulence models for the closure of Reynolds Averaged Navier-Stokes (RANS) simulations. Machine Learning (ML) offers effective tools for establishing advanced empirical Reynolds stress closures on…

Fluid Dynamics · Physics 2021-04-01 Muyuan Liu , Yiren Yang , Hao Chen

Deep convolutional neural networks (CNN) have recently been shown in many computer vision and pattern recog- nition applications to outperform by a significant margin state- of-the-art solutions that use traditional hand-crafted features.…

Robotics · Computer Science 2015-04-22 Yi Hou , Hong Zhang , Shilin Zhou

Predictive wavefront control is an important and rapidly developing field of adaptive optics (AO). Through the prediction of future wavefront effects, the inherent AO system servo-lag caused by the measurement, computation, and application…

Instrumentation and Methods for Astrophysics · Physics 2021-03-12 Robin Swanson , Masen Lamb , Carlos Correia , Suresh Sivanandam , Kiriakos Kutulakos

We show that in addition to providing effective and competitive closures, when analysed in terms of dynamics and physically-relevant diagnostics, artificial neural networks (ANNs) can be both interpretable and provide useful insights in the…

Computational Physics · Physics 2020-12-30 Gavin D. Portwood , Balasubramanya T. Nadiga , Juan A. Saenz , Daniel Livescu

Commonly used wavefront sensors, the Shack Hartmann wavefront sensor and the pyramid wavefront sensor, for example, have large dynamic range or high sensitivity, trading one regime for the other. A new type of wavefront sensor is being…

Instrumentation and Methods for Astrophysics · Physics 2022-08-19 Meghan Farris O'Brien , Sebastiaan Y. Haffert , Joseph D. Long , Lauren Schatz , Jared R. Males , Kyle Van Gorkom , Alex Rodack

Learning acoustic models directly from the raw waveform data with minimal processing is challenging. Current waveform-based models have generally used very few (~2) convolutional layers, which might be insufficient for building high-level…

Sound · Computer Science 2016-10-04 Wei Dai , Chia Dai , Shuhui Qu , Juncheng Li , Samarjit Das

Dense pixelwise prediction such as semantic segmentation is an up-to-date challenge for deep convolutional neural networks (CNNs). Many state-of-the-art approaches either tackle the loss of high-resolution information due to pooling in the…

Computer Vision and Pattern Recognition · Computer Science 2018-08-07 Lingni Ma , Jörg Stückler , Tao Wu , Daniel Cremers

Focal plane wavefront sensing (FPWFS) is appealing for several reasons. Notably, it offers high sensitivity and does not suffer from non-common path aberrations (NCPA). The price to pay is a high computational burden and the need for…

Instrumentation and Methods for Astrophysics · Physics 2021-07-14 G. Orban de Xivry , M. Quesnel , P. -O. Vanberg , O. Absil , G. Louppe

Wavefront sensors encode phase information of an incoming wavefront into an intensity pattern that can be measured on a camera. Several kinds of wavefront sensors (WFS) are used in astronomical adaptive optics. Amongst them, Fourier-based…

The Trapped Gyro-Landau Fluid (TGLF) model provides fast, accurate predictions of turbulent transport in tokamaks, but whole device simulations requiring thousands of evaluations remain computationally expensive. Neural network (NN)…

Several Tensor Basis Neural Network (TBNN) frameworks aimed at enhancing turbulence RANS modeling have recently been proposed in the literature as data-driven constitutive models for systems with known invariance properties. However,…

Neural networks with self-attention (a.k.a. Transformers) like ViT and Swin have emerged as a better alternative to traditional convolutional neural networks (CNNs). However, our understanding of how the new architecture works is still…

Computer Vision and Pattern Recognition · Computer Science 2023-12-15 Juyeop Kim , Junha Park , Songkuk Kim , Jong-Seok Lee

Deep neural networks (DNNs) are widely used as surrogate models in geophysical applications; incorporating theoretical guidance into DNNs has improved the generalizability. However, most of such approaches define the loss function based on…

Machine Learning · Computer Science 2021-09-28 Rui Xu , Dongxiao Zhang , Miao Rong , Nanzhe Wang

Full-Waveform Inversion seeks to achieve a high-resolution model of the subsurface through the application of multi-variate optimization to the seismic inverse problem. Although now a mature technology, FWI has limitations related to the…

Geophysics · Physics 2025-02-26 Christopher Zerafa , Pauline Galea , Cristiana Sebu

Turbulence is notoriously difficult to model due to its multi-scale nature and sensitivity to small perturbations. Classical solvers of turbulence simulation generally operate on finer grids and are computationally inefficient. In this…

Fluid Dynamics · Physics 2022-07-12 Yuchen Dang , Zheyuan Hu , Miles Cranmer , Michael Eickenberg , Shirley Ho

Consistent operation of adaptive optics (AO) systems requires the use of a wavefront sensor (WFS) with high sensitivity and low noise. The nonlinear curvature WFS (nlCWFS) has been shown both in simulations and lab experiments to be more…

Instrumentation and Methods for Astrophysics · Physics 2023-12-05 Sam Potier , Justin Crepp , Stanimir Letchev