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Linear Hall sensors are a cost-effective alternative to optical encoders for measuring the rotor positions of actuators, with the main challenge being that they exhibit position-dependent inaccuracies resulting from manufacturing…

Systems and Control · Electrical Eng. & Systems 2025-05-08 Max van Meer , Marijn van Noije , Koen Tiels , Enzo Evers , Lennart Blanken , Gert Witvoet , Tom Oomen

Block-Oriented Nonlinear (BONL) models, particularly Wiener models, are widely used for their computational efficiency and practicality in modeling nonlinear behaviors in physical systems. Filtering and smoothing methods for Wiener systems,…

Systems and Control · Electrical Eng. & Systems 2025-05-14 Angel L. Cedeño , Rodrigo A. González , Juan C. Agüero

This paper describes the optimisation theory on which VPFIT, a non-linear least-squares program for modelling absorption spectra, is based. Particular attention is paid to precision. Voigt function derivatives have previously been…

Instrumentation and Methods for Astrophysics · Physics 2021-10-20 John K. Webb , Robert F. Carswell , Chung-Chi Lee

We present an overview of the Velocity Coordinate Spectrum (VCS), a new technique for studying astrophysical turbulence that utilizes the line-of-sight statistics of Doppler-broadened spectral lines. We consider the retrieval of turbulence…

Astrophysics of Galaxies · Physics 2009-02-03 D. Pogosyan , A. Lazarian

An arbitrary optical waveform can be synthesized by complex-frequency waves as well as by realfrequency harmonic waves. While single complex-frequency wave with exponentially rising waveform can be perfectly absorbed in lossless structures.…

Optics · Physics 2025-12-22 Zhaohua Tian , Yu Tian , Yadi Niu , Qi Liu , Zihan Mo , Haoyang Zhang , Qihuang Gong , Ying Gu

The lensless endoscope is a promising device designed to image tissues in vivo at the cellular scale. The traditional acquisition setup consists in raster scanning during which the focused light beam from the optical fiber illuminates…

Computer Vision and Pattern Recognition · Computer Science 2018-10-31 Stéphanie Guérit , Siddharth Sivankutty , Camille Scotté , John Alto Lee , Hervé Rigneault , Laurent Jacques

The presence of interharmonics in power systems can lead to asynchronous sampling, a phenomenon further aggravated by shifts in the fundamental frequency, which significantly degrades the accuracy of power measurements. Under such…

Signal Processing · Electrical Eng. & Systems 2026-01-30 Jian Liu , Wei Zhao , Jianting Zhao , Shisong Li

In this work, we propose an adaptive spectral element algorithm for solving nonlinear optimal control problems. The method employs orthogonal collocation at the shifted Gegenbauer-Gauss points combined with very accurate and stable…

Optimization and Control · Mathematics 2023-03-06 Kareem T. Elgindy

Accurate measurement of light wavelength is critical for applications in spectroscopy, optical communication, and semiconductor manufacturing, ensuring precision and consistency of sensing, high-speed data transmission and device…

A novel and highly efficient computational framework for reconstructing binary-type images suitable for models of various complexity seen in diverse biomedical applications is developed and validated. Efficiency in computational speed and…

Optimization and Control · Mathematics 2024-02-09 Paul R. Arbic , Vladislav Bukshtynov

An accurate treatment of electronic spectra in large systems with a technique such as time dependent density functional theory (TDDFT) is computationally challenging. Due to the Nyquist sampling theorem, direct real time simulations must be…

Materials Science · Physics 2024-01-17 Matthias Kick , Ezra Alexander , Anton Beiersdorfer , Troy Van Voorhis

A high order wavelet integral collocation method (WICM) is developed for general nonlinear boundary value problems in physics. This method is established based on Coiflet approximation of multiple integrals of interval bounded functions…

Numerical Analysis · Mathematics 2017-04-26 Lei Zhang , Jizeng Wang , Xiaojing Liu , Youhe Zhou

We present an approach to spectropolarimetry which requires neither moving parts nor time dependent modulation, and which offers the prospect of achieving high sensitivity. The technique applies equally well, in principle, in the optical,…

Instrumentation and Methods for Astrophysics · Physics 2015-06-05 William Sparks , Thomas A. Germer , John MacKenty , Frans Snik

In this paper, we propose Fourier pseudospectral methods to solve the variable-order space fractional wave equation and develop an accelerated matrix-free approach for its effective implementation. In constant-order cases, our methods can…

Numerical Analysis · Mathematics 2024-02-06 Yanzhi Zhang , Xiaofei Zhao , Shiping Zhou

Synthetic Magnetic Resonance (MR) imaging predicts images at new design parameter settings from a few observed MR scans. Model-based methods, that use both the physical and statistical properties underlying the MR signal and its…

Applications · Statistics 2023-08-25 Subrata Pal , Somak Dutta , Ranjan Maitra

We consider minimization of composite functions of the form $f(g(x))+h(x)$, where $f$ and $h$ are convex functions (which can be nonsmooth) and $g$ is a smooth vector mapping. In addition, we assume that $g$ is the average of finite number…

Optimization and Control · Mathematics 2021-05-17 Junyu Zhang , Lin Xiao

We develop an efficient algorithm for Synthetic Aperture Sonar imaging based on the one-way wave equations. The algorithm utilizes the operator-splitting method to integrate the one-way wave equations. The well-posedness of the one-way wave…

Numerical Analysis · Mathematics 2009-07-14 Quyen Huynh , Kazufumi Ito

We investigate methods to calibrate the non-common path aberrations at an adaptive optics system having a wavefront-correcting device working at an extremely high resolution (larger than 150x150). We use focal-plane images collected…

Instrumentation and Methods for Astrophysics · Physics 2015-06-22 Visa Korkiakoski , Christoph U. Keller , Niek Doelman , Matthew Kenworthy , Gilles Otten , Michel Verhaegen

Excalibur is a non-parametric, hierarchical framework for precision wavelength-calibration of spectrographs. It is designed with the needs of extreme-precision radial velocity (EPRV) in mind, which require that instruments be calibrated or…

Instrumentation and Methods for Astrophysics · Physics 2021-01-27 L. L. Zhao , D. W. Hogg , M. Bedell , D. A. Fischer

We propose a robust calibration pipeline that optimises the selection of calibration samples for the estimation of calibration parameters that fit the entire scene. We minimise user error by automating the data selection process according…

Computer Vision and Pattern Recognition · Computer Science 2021-09-23 Darren Tsai , Stewart Worrall , Mao Shan , Anton Lohr , Eduardo Nebot