English
Related papers

Related papers: INGOT WFS for LGSs: First Results from Simulations

200 papers

The low wind effect (LWE) refers to a characteristic set of quasi-static wavefront aberrations seen consistently by the SPHERE instrument when dome-level wind speeds drop below 3 m/s. This effect produces bright low-order speckles in the…

Instrumentation and Methods for Astrophysics · Physics 2018-07-18 Michael J. Wilby , Christoph U. Keller , Jean-Francois Sauvage , Kjetil Dohlen , Thierry Fusco , David Mouillet , Jean-Luc Beuzit

Laser guide stars (LGSs) have been deployed for the last 20-30 years in ground-based astronomical telescopes to overcome the limited sky coverage of classical adaptive optics (AO) systems. Unfortunately, slow altitude drifts of the sodium…

The correction of quasi-static wavefront errors within a coronagraphic optical system will be a key challenge to overcome in order to directly image exoplanets in reflected light. These quasi-static errors are caused by mid to high-order…

Instrumentation and Methods for Astrophysics · Physics 2024-06-28 Kian Milani , Ewan Douglas , Leonid Pogorelyuk , Christopher Mendillo , Kerri Cahoy , Nicholas Belsten , Brandon Eickert , Shanti Rao

We propose a novel control approach that combines offline supervised learning to address the challenges posed by non-linear phase reconstruction using unmodulated pyramid wavefront sensors (P-WFS) and online reinforcement learning for…

Instrumentation and Methods for Astrophysics · Physics 2024-05-24 Bartomeu Pou , Jeffrey Smith , Eduardo Quinones , Mario Martin , Damien Gratadour

Several methods have been developed for the simulation of the Hawkes process. The oldest approach is the inverse sampling transform (ITS) suggested in \citep{ozaki1979maximum}, but rapidly abandoned in favor of more efficient alternatives.…

Econometrics · Economics 2019-07-23 Martin Magris

We have designed and constructed a ``dispersed Fourier Transform Spectrometer'' (dFTS), consisting of a conventional FTS followed by a grating spectrometer. By combining these two devices, we negate a substantial fraction of the sensitivity…

The special affine Fourier transform (SAFT) is a promising tool for analyzing non-stationary signals with more degrees of freedom. However, the SAFT fails in obtaining the local features of non-transient signals due to its global kernel and…

Functional Analysis · Mathematics 2020-06-11 Firdous A. Shah , Azhar Y. Tantary , Aajaz A. Teali

The interstellar medium (ISM) is a complex non-linear system governed by gravity and magneto-hydrodynamics, as well as radiative, thermodynamical, and chemical processes. Our understanding of it mostly progresses through observations and…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-25 E. Allys , F. Levrier , S. Zhang , C. Colling , B. Regaldo-Saint Blancard , F. Boulanger , P. Hennebelle , S. Mallat

We present PhySG, an end-to-end inverse rendering pipeline that includes a fully differentiable renderer and can reconstruct geometry, materials, and illumination from scratch from a set of RGB input images. Our framework represents…

Computer Vision and Pattern Recognition · Computer Science 2021-04-02 Kai Zhang , Fujun Luan , Qianqian Wang , Kavita Bala , Noah Snavely

Accurately simulating the atmospheric turbulence behaviour is always challenging. The well-known FFT based method falls short in correctly predicting both the low and high frequency behaviours. Sub-harmonic compensation aids in…

Instrumentation and Methods for Astrophysics · Physics 2022-08-15 Sorabh Chhabra , Jyotirmay Paul , A. N. Ramaprakash , Avinash Surendran

This paper unveils the importance of intelligent reflecting surface (IRS) in a wireless powered sensor network (WPSN). Specifically, a multi-antenna power station (PS) employs energy beamforming to provide wireless charging for multiple…

Signal Processing · Electrical Eng. & Systems 2021-03-22 Zheng Chu , Zhengyu Zhu , Miao Zhang , Fuhui Zhou , Li Zhen , Xueqian Fu , and Naofal Al-Dhahir

We propose a new splitting method for strong numerical solution of the Cox-Ingersoll-Ross model. For this method, applied over both deterministic and adaptive random meshes, we prove a uniform moment bound and strong error results of order…

Numerical Analysis · Mathematics 2023-02-08 Cónall Kelly , Gabriel J. Lord

The concept of two perpendicular one-dimensional coded aperture cameras, necessitated by the imaging capability of the detector, finds its application in the design of the Wide Field Monitor (WFM). This instrument has the future goal to…

Instrumentation and Methods for Astrophysics · Physics 2026-05-13 J. J. M. in 't Zand , L. Kuiper , F. Ceraudo , Y. Evangelista , M. Hernanz , A. Patruno

The Multiconjugate Adaptive optics Demonstrator (MAD) has successfully demonstrated on sky both Star Oriented (SO) and Layer Oriented (LO) multiconjugate adaptive optics techniques. While SO has been realized using 3 Shack-Hartmann…

Given a multi-input, nonlinear, time-invariant, control-affine system and a controlled invariant, closed, embedded submanifold $\mathsf{N}$, the local transverse feedback linearization (TFL) problem seeks a coordinate and feedback…

Optimization and Control · Mathematics 2022-04-29 Rollen S. D'Souza , Christopher Nielsen

We use cosmological hydrodynamic simulations with stellar feedback from the FIRE project to study the physical nature of Lyman limit systems (LLSs) at z<1. At these low redshifts, LLSs are closely associated with dense gas structures…

Astrophysics of Galaxies · Physics 2017-06-21 Z. Hafen , C. -A. Faucher-Giguere , D. Angles-Alcazar , D. Keres , R. Feldmann , T. K. Chan , E. Quataert , N. Murray , P. F. Hopkins

This paper focuses on the fundamental problem of maximizing the achievable weighted sum rate (WSR) at information receivers (IRs) in an intelligent reflecting surface (IRS) assisted simultaneous wireless information and power transfer…

Signal Processing · Electrical Eng. & Systems 2023-03-02 Vaibhav Kumar , Anastasios Papazafeiropoulos , Muhammad Fainan Hanif , Le-Nam Tran , Mark F. Flanagan

The nonlinear curvature wavefront sensor (nlCWFS) has been shown to be a promising alternative to existing wavefront sensor designs. Theoretical studies indicate that the inherent sensitivity of this device could offer up to a factor of 10…

Instrumentation and Methods for Astrophysics · Physics 2022-09-02 Stanimir Letchev , Jonathan Crass , Justin R. Crepp , Sam Potier

Extended full-waveform inversion (FWI) has shown promising results for accurate estimation of subsurface parameters when the initial models are not sufficiently accurate. Frequency-domain applications have shown that the augmented…

Numerical Analysis · Mathematics 2021-09-16 Ali Gholami , Hossein S. Aghamiry , Stephane Operto

Traditional star formation subgrid models implemented in cosmological galaxy formation simulations, such as that of Springel & Hernquist (2003, hereafter SH03), employ adjustable parameters to satisfy constraints measured in the local…