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The modal decomposition techniques of proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD) have become a common method for analysing the spatio-temporal coherence of dynamical systems. In particular, these techniques…

Fluid Dynamics · Physics 2019-09-18 Scott B. Leask , Vincent G. McDonell

Recent studies have shown convolutional neural networks (CNNs) can be trained to perform modal decomposition using intensity images of optical fields. A fundamental limitation of these techniques is that the modal phases can not be uniquely…

Optics · Physics 2021-04-20 Mitchell G. Schiworski , Daniel D. Brown , David J. Ottaway

The famous Fourier theorem states that, under some restrictions, any periodic function (or real world signal) can be obtained as a sum of sinusoids, and hence, a technique exists for decomposing a signal into its sinusoidal components. From…

Numerical Analysis · Computer Science 2008-04-24 Sossio Vergara

Time periodic patterns in a semiconductor superlattice, relevant to microwave generation, are obtained upon numerical integration of a known set of drift-diffusion equations. The associated spatio-temporal transport mechanisms are uncovered…

Materials Science · Physics 2021-10-01 F. Terragni , L. L. Bonilla , J. M. Vega

We present approaches for the study of fluid-structure interactions subject to thermal fluctuations. A mixed mechanical description is utilized combining Eulerian and Lagrangian reference frames. We establish general conditions for…

Soft Condensed Matter · Physics 2023-02-28 Paul J. Atzberger

Data analysis is a powerful tool in all experimental sciences. Statistical methods, such as sampling theory, computer technologies necessary for handling large amounts of data, skill in analysing information contained in different types of…

Physics Education · Physics 2012-06-20 Vera Montalbano

This work aims to improve fuel chamber injectors' performance in turbofan engines, thus implying improved performance and reduction of pollutants. This requires the development of models that allow real-time prediction and improvement of…

Machine Learning · Computer Science 2023-06-21 León Mata , Rodrigo Abadía-Heredia , Manuel Lopez-Martin , José M. Pérez , Soledad Le Clainche

Modeling turbulent flows by a random Fourier decomposition is a classical procedure in order to use simplified models of turbulence in heat transport and other applications. We carefully investigate the Fourier time series of…

Mathematical Physics · Physics 2026-05-14 Paolo Cifani , Franco Flandoli , Andrea Zanoni

Particle-based velocimetry (PV) is a widely used technique for non-invasive flow field measurements in fluid mechanics. Existing PV measurements typically rely on a single type of particle recording. With advancements in deep learning and…

Fluid Dynamics · Physics 2025-07-10 Fan Wu , Xiang Feng , Aoyu Zhang , Yong Lee

Signal decomposition and multiscale signal analysis provide many useful tools for time-frequency analysis. We proposed a random feature method for analyzing time-series data by constructing a sparse approximation to the spectrogram. The…

Signal Processing · Electrical Eng. & Systems 2023-03-17 Nicholas Richardson , Hayden Schaeffer , Giang Tran

To obtain fast solutions for governing physical equations in solid mechanics, we introduce a method that integrates the core ideas of the finite element method with physics-informed neural networks and concept of neural operators. This…

We present an approach to construct approximate Koopman-type decompositions for dynamical systems depending on static or time-varying parameters. Our method simultaneously constructs an invariant subspace and a parametric family of…

Optimization and Control · Mathematics 2024-11-12 Yue Guo , Milan Korda , Ioannis G. Kevrekidis , Qianxiao Li

Particle Image Velocimetry (PIV) is a widely adopted non-invasive imaging technique that tracks the motion of tracer particles across image sequences to capture the velocity distribution of fluid flows. It is commonly employed to analyze…

Computer Vision and Pattern Recognition · Computer Science 2026-01-05 Yunzhong Zhang , Bo Xiong , You Zhou , Changqing Su , Zhen Cheng , Zhaofei Yu , Xun Cao , Tiejun Huang

We perform a Fourier space decomposition of the dynamics of non-linear cosmological structure formation in LCDM models. From N-body simulations involving only cold dark matter we calculate 3-dimensional non-linear density, velocity…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-21 Jacob Brandbyge , Steen Hannestad

This is lecture notes on the course "Stochastic Processes". In this format, the course was taught in the spring semesters 2017 and 2018 for third-year bachelor students of the Department of Control and Applied Mathematics, School of Applied…

The research community has witnessed the powerful potential of self-supervised Masked Image Modeling (MIM), which enables the models capable of learning visual representation from unlabeled data. In this paper, to incorporate both the…

Computer Vision and Pattern Recognition · Computer Science 2023-12-01 Wenxuan Wang , Jing Wang , Chen Chen , Jianbo Jiao , Yuanxiu Cai , Shanshan Song , Jiangyun Li

Accurate skin lesion segmentation from dermoscopic images is of great importance for skin cancer diagnosis. However, automatic segmentation of melanoma remains a challenging task because it is difficult to incorporate useful texture…

Image and Video Processing · Electrical Eng. & Systems 2024-09-16 Rongtao Xu , Changwei Wang , Jiguang Zhang , Shibiao Xu , Weiliang Meng , Xiaopeng Zhang

We propose a new point of view in the study of Fourier analysis on graphs, taking advantage of localization in the Fourier domain. For a signal $f$ on vertices of a weighted graph $\mathcal{G}$ with Laplacian matrix $\mathcal{L}$, standard…

Signal Processing · Electrical Eng. & Systems 2021-12-02 Basile de Loynes , Fabien Navarro , Baptiste Olivier

Recently, several single-pixel imaging (SPI) schemes have emerged for imaging fast-moving objects and have shown dramatic results. However, fast image reconstruction of a moving object with high quality is still challenging for SPI, thereby…

Optics · Physics 2024-10-08 Shijian Li , Xu-Ri Yao , Wei Zhang , Yeliang Wang , Qing Zhao

These are notes for a set of 7 two-hour lectures given at the 2010 Summer School on Quantitative Evolutionary and Comparative Genomics at OIST, Okinawa, Japan. The emphasis is on understanding how biological systems process information. We…

Molecular Networks · Quantitative Biology 2010-06-23 Gašper Tkačik