English
Related papers

Related papers: Directional short-time Fourier transform and direc…

200 papers

In this paper we generalize the continuous quaternion windowed Fourier transform called the multivariate two sided continuous quaternion windowed Fourier transform. Using the two sided quaternion Fourier transform we derive several…

Classical Analysis and ODEs · Mathematics 2019-06-21 Kamel Brahim , Emna Tefjeni

We introduce discrete wave-front sets with respect to Fourier Lebesgue and modulation spaces. We prove that these wave-front sets agree with corresponding wave-front sets of "continuous type".

Functional Analysis · Mathematics 2009-09-08 Karoline Johansson , Stevan Pilipovic , Nenad Teofanov , Joachim Toft

A new concept, called the spatio-temporal transfer function (STTF), is introduced to characterise a class of linear time-invariant (LTI) spatio-temporal dynamical systems. The spatio-temporal transfer function is a natural extension of the…

Systems and Control · Electrical Eng. & Systems 2021-11-04 Hua-Liang Wei , Stephen A. Billings

In this paper, we extend the coupled fractional Fourier transform of a complex valued functions to that of the quaternion valued functions on $\mathbb{R}^4$ and call it the quaternion coupled fractional Fourier transform (QCFrFT). We obtain…

General Mathematics · Mathematics 2023-10-02 Bivek Gupta , Amit K. Verma , Ravi P. Agarwal

The data analysis of space-based gravitational wave detectors like Taiji faces significant challenges from non-stationary noise, which compromises the efficacy of traditional frequency-domain analysis. This work proposes a unified framework…

General Relativity and Quantum Cosmology · Physics 2025-06-23 Minghui Du , Ziren Luo , Peng Xu

We present an extension of the second-principles density functional theory (SPDFT) method to perform time-dependent simulations. Our approach, which calculates the evolution of the density matrix in real time and real space using the…

Materials Science · Physics 2025-07-21 Toraya Fernández-Ruiz , Jorge Íñiguez , Javier Junquera , Pablo García-Fernández

Continuous symmetries are fundamental to many scientific and learning problems, yet they are often unknown a priori. Existing symmetry discovery approaches typically search directly in the space of transformation generators or rely on…

Machine Learning · Computer Science 2026-03-10 Pavan Karjol , Kumar Shubham , Prathosh AP

We study the statistics of the vertical motion of inertial particles in strongly stratified turbulence. We use Kinematic Simulation (KS) and Rapid Distortion Theory (RDT) to study the mean position and the root mean square (rms) of the…

Fluid Dynamics · Physics 2017-08-28 F. C. G. A. Nicolleau , K. -S. Sung , J. C. Vassilicos

We examine the out-of-equilibrium dynamical evolution of density profiles of ultrasoft particles under time-varying external confining potentials in three spatial dimensions. The theoretical formalism employed is the dynamical density…

Soft Condensed Matter · Physics 2009-11-10 J. Dzubiella , C. N. Likos

A mathematical relation between elements of one- and multi-dimensional discrete Fourier transforms (DFT) is found. A method of analysing the multi-dimensional data by their single one-dimensional (1-D) DFT is offered. An experiment of…

Numerical Analysis · Mathematics 2025-10-20 Andrew V. Batrac

A new definition of a fractional derivative has recently been developed, making use of a fractional Dirac delta function as its integral kernel. This derivative allows for the definition of a distributional fractional derivative, and as…

Classical Analysis and ODEs · Mathematics 2018-05-16 Evan Camrud

In this paper, we study a special one dimensional quaternion short-time Fourier transform (QSTFT). Its construction is based on the slice hyperholomorphic Segal-Bargmann transform. We discuss some basic properties and prove different…

Complex Variables · Mathematics 2020-09-02 Antonino De Martino , Kamal Diki

Graph signal processing (GSP) facilitates the analysis of high-dimensional data on non-Euclidean domains by utilizing graph signals defined on graph vertices. In addition to static data, each vertex can provide continuous time-series…

Signal Processing · Electrical Eng. & Systems 2025-02-21 Tuna Alikaşifoğlu , Bünyamin Kartal , Eray Özgünay , Aykut Koç

Density functional theory (DFT) is an essential building block for modern theoretical physics, chemistry, and engineering, especially those concerning electronic properties. Through decades of development, various program packages for…

Materials Science · Physics 2022-11-21 Yusuke Nomura , Ryosuke Akashi

Recently, the theory concerning piecewise smooth vector fields (PSVFs for short) have been undergoing important improvements. In fact, many results obtained do not have an analogous for smooth vector fields. For example, the chaoticity of…

Dynamical Systems · Mathematics 2021-12-07 Andre Amaral Antunes , Tiago Carvalho

In this contribution we generalize the classical Fourier Mellin transform [S. Dorrode and F. Ghorbel, Robust and efficient Fourier-Mellin transform approximations for gray-level image reconstruction and complete invariant description,…

Rings and Algebras · Mathematics 2013-06-10 Eckhard Hitzer

Universal conductance fluctuations are usually observed in the form of aperiodic oscillations in the magnetoresistance of thin wires as a function of the magnetic field B. If such oscillations are completely random at scales exceeding…

Disordered Systems and Neural Networks · Physics 2021-12-28 I. M. Suslov

Very recently the most general ensemble of qubits are identified using the notion of linearity; any of these qubits gets accepted by a Hadamard gate to generate the equal superposition of the qubit and its orthogonal. Towards more…

Quantum Physics · Physics 2012-08-28 Arpita Maitra

Variational mode decomposition (VMD) and its extensions like Multivariate VMD (MVMD) decompose signals into ensembles of band-limited modes with narrow central frequencies. These methods utilize Fourier transformations to shift signals…

Information Theory · Computer Science 2025-01-17 Hao Jia , Pengfei Cao , Tong Liang , Cesar F. Caiafa , Zhe Sun , Yasuhiro Kushihashi , Grau A , Bolea Y , Feng Duan , Jordi Sole-Casals

In this paper, we study the error behavior of the nonequispaced fast Fourier transform (NFFT). This approximate algorithm is mainly based on the convenient choice of a compactly supported window function. So far, various window functions…

Numerical Analysis · Mathematics 2021-08-25 Daniel Potts , Manfred Tasche