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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 fractional Fourier transform (FRFT) naturally exists in the strongly nonlocal nonlinear (SNN) media and the propagation of optical beams in SNN media can be simply regarded as a self-induced FRFT. Through FRFT technic the evolution of…

Optics · Physics 2008-12-17 Daquan Lu , Wei Hu , Yajian zheng , Yanbin liang , Longgui Cao , Sheng Lan , Qi Guo

The Fast Fourier Transform is extended to functions on finite graphs whose edges are identified with intervals of finite length. Spectral and pseudospectral methods are developed to solve a wide variety of time dependent partial…

Numerical Analysis · Mathematics 2025-07-11 Robert Carlson

Training diffusion models on limited datasets poses challenges in terms of limited generation capacity and expressiveness, leading to unsatisfactory results in various downstream tasks utilizing pretrained diffusion models, such as domain…

Computer Vision and Pattern Recognition · Computer Science 2023-11-03 Jiwan Hur , Jaehyun Choi , Gyojin Han , Dong-Jae Lee , Junmo Kim

This paper introduces a design method for densergraph-frequency graph Fourier frames (DGFFs) to enhance graph signal processing and analysis. The graph Fourier transform (GFT) enables us to analyze graph signals in the graph spectral domain…

Signal Processing · Electrical Eng. & Systems 2025-03-18 Kaito Nitani , Seisuke Kyochi

Digital signal processing is a valuable practical skill for the contemporary physicist, yet in physics curricula its central concepts are often introduced either in method courses in a highly abstract and mathematics-oriented manner or in…

Image computation is a fundamental tool for performance assessment of astronomical instrumentation, usually implemented by Fourier transform techniques. We review the numerical implementation, evaluating a direct implementation of the…

Astrophysics · Physics 2008-11-26 M. Gai , R. Cancelliere

In this paper, we propose a differentiable version of the short-time Fourier transform (STFT) that allows for gradient-based optimization of the hop length or the frame temporal position by making these parameters continuous. Our approach…

Signal Processing · Electrical Eng. & Systems 2023-08-07 Maxime Leiber , Yosra Marnissi , Axel Barrau , Mohammed El Badaoui

The 3D Discrete Fourier Transform (DFT) is a technique used to solve problems in disparate fields. Nowadays, the commonly adopted implementation of the 3D-DFT is derived from the Fast Fourier Transform (FFT) algorithm. However, evidence…

Computational Physics · Physics 2024-07-10 Nitin Malapally , Viacheslav Bolnykh , Estela Suarez , Paolo Carloni , Thomas Lippert , Davide Mandelli

Density functional theory (DFT) has become the most popular approach to electronic structure across disciplines, especially in material and chemical sciences. Last year, at least 30,000 papers used DFT to make useful predictions or give…

Chemical Physics · Physics 2017-01-05 Justin C. Smith , Francisca Sagredo , Kieron Burke

The FFT algorithm that implements the discrete Fourier transform is considered one of the top ten algorithms of the $20$th century. Its main strengths are the low computational cost of $\mathcal{O}(n \log n$) and its stability. It is one of…

Numerical Analysis · Mathematics 2017-06-15 Matteo Briani , Annie Cuyt , Wen-shin Lee

The graph Fourier transform (GFT) is a fundamental tool in graph signal processing and has recently been extended to the graph fractional Fourier transform (GFRFT). Existing sampling methods in the GFRFT domain are primarily designed to…

General Mathematics · Mathematics 2026-05-27 Yu Zhang , Jia-Yin Peng , Bing-Zhao Li

Modern applications of Covariant Density Functional Theory (CDFT) are discussed. First we show a systematic investigation of fission barriers in actinide nuclei within constraint relativistic mean field theory allowing for triaxial…

Nuclear Theory · Physics 2011-09-20 P. Ring , H. Abusara , A. V. Afanasjev , G. A. Lalazissis , T. Niksic , D. Vretenar

In distributed radar systems, when several transmitters radiate simultaneously, the reflected signals need to be distinguished at the receivers to detect various targets. If the transmit signals are in different frequency bands, they…

Signal Processing · Electrical Eng. & Systems 2024-01-02 Gokularam Muthukrishnan , S. Sruti , K. Giridhar

The Fractional Fourier Transform (FRFT) has been playing a unique and increasingly important role in signal and image processing. In this letter, we investigate the property of frequency shift in two-dimensional FRFT (2D-FRFT) domain. It is…

Signal Processing · Electrical Eng. & Systems 2021-03-02 Lei Gao , Lin Qi , Ling Guan

Density functional theory (DFT) became a universal approach to compute ground-state and excited configurations of many-electron systems held together by an external one-body potential in condensed-matter, atomic, and molecular physics. At…

Nuclear Theory · Physics 2011-09-30 J. Dobaczewski

We study the problem of constructing a graph Fourier transform (GFT) for directed graphs (digraphs), which decomposes graph signals into different modes of variation with respect to the underlying network. Accordingly, to capture low,…

Signal Processing · Electrical Eng. & Systems 2019-01-30 Rasoul Shafipour , Ali Khodabakhsh , Gonzalo Mateos , Evdokia Nikolova

This paper introduces a new tool for time-series analysis: the Sliding Window Discrete Fourier Transform (SWDFT). The SWDFT is especially useful for time-series with local- in-time periodic components. We define a 5-parameter model for…

Methodology · Statistics 2018-07-23 Lee F. Richardson , William F. Eddy

Graph Fourier transform (GFT) is one of the fundamental tools in graph signal processing to decompose graph signals into different frequency components and to represent graph signals with strong correlation by different modes of variation…

Information Theory · Computer Science 2022-09-08 Cheng Cheng , Yang Chen , Jeon Yu Lee , Qiyu Sun

This paper refers to the study of generalized Struve type function. Using generalized Galue type Struve function (GTSF) by Nisar et al. [13], we derive various integral transform, including Euler transform, Laplace transform, Whittakar…

Classical Analysis and ODEs · Mathematics 2016-07-19 D. L. Suthar , S. D. Purohit , K. S. Nisar