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We present a Chebyshev collocation method for linear ODE and DDE problems. We first give a posteriori estimates for the accuracy of the approximate solution of a scalar ODE initial value problem. Examples of the success of the estimate are…

Numerical Analysis · Mathematics 2024-08-15 Ed Bueler

We consider dimensional reduction techniques for the Liouville-von Neumann equation for the evaluation of the expectation values in a mixed quantum system. In applications such as nuclear spin dynamics the main goal for simulations is being…

Numerical Analysis · Mathematics 2010-03-18 Giacomo Mazzi , Ben Leimkuhler

This study explores the use of a digital twin model and deep learning method to build a global terrain and altitude map based on USGS information. The goal is to artistically represent various landforms while incorporating precise elevation…

Image and Video Processing · Electrical Eng. & Systems 2023-05-25 Mohsen Ahmadi , Ahmad Gholizadeh Lonbar , Mohammadsadegh Nouri , Amir Sharifzadeh Javidi , Ali Tarlani Beris , Abbas Sharifi , Ali Salimi-Tarazouj

The aim of the present work is to introduce a method based on Chebyshev polynomials for the numerical solution of a system of Cauchy type singular integral equations of the first kind on a finite segment. Moreover, an estimation error is…

Numerical Analysis · Mathematics 2015-08-11 Sedaghat Shahmorad , Samad Ahdiaghdam

Ultrasound images are widespread in medical diagnosis for musculoskeletal, cardiac, and obstetrical imaging due to the efficiency and non-invasiveness of the acquisition methodology. However, the acquired images are degraded by acoustic…

Image and Video Processing · Electrical Eng. & Systems 2023-06-14 Hojat Asgariandehkordi , Sobhan Goudarzi , Adrian Basarab , Hassan Rivaz

In this paper we consider the numerical solution of fractional differential equations. In particular, we study a step-by-step graded mesh procedure based on an expansion of the vector field using orthonormal Jacobi polynomials. Under mild…

Numerical Analysis · Mathematics 2024-04-09 L. Brugnano , K. Burrage , P. Burrage , F. Iavernaro

Data representation techniques have made a substantial contribution to advancing data processing and machine learning (ML). Improving predictive power was the focus of previous representation techniques, which unfortunately perform rather…

Machine Learning · Computer Science 2022-05-24 Qiyou Duan , Hadi Ghauch , Taejoon Kim

We present a numerical scheme that can be combined with any fixed boundary finite element based Poisson or Grad-Shafranov solver to compute the first and second partial derivatives of the solution to these equations with the same order of…

Numerical Analysis · Mathematics 2015-07-29 L. F. Ricketson , A. J. Cerfon , M. Rachh , J. P. Freidberg

In this paper we consider an orthonormal basis, generated by a tensor product of Fourier basis functions, half period cosine basis functions, and the Chebyshev basis functions. We deal with the approximation problem in high dimensions…

Numerical Analysis · Mathematics 2024-04-26 Daniel Potts , Pascal Schröter

Denoising Diffusion Probabilistic Models (DDPMs) can generate high-quality samples such as image and audio samples. However, DDPMs require hundreds to thousands of iterations to produce final samples. Several prior works have successfully…

Computer Vision and Pattern Recognition · Computer Science 2022-11-01 Luping Liu , Yi Ren , Zhijie Lin , Zhou Zhao

Monitoring and managing Earth's forests in an informed manner is an important requirement for addressing challenges like biodiversity loss and climate change. While traditional in situ or aerial campaigns for forest assessments provide…

Computer Vision and Pattern Recognition · Computer Science 2022-12-13 Alexander Becker , Stefania Russo , Stefano Puliti , Nico Lang , Konrad Schindler , Jan Dirk Wegner

In this work, we focused on deep learning image processing in the context of oral rare diseases, which pose challenges due to limited data availability. A crucial step involves teeth detection, segmentation and numbering in panoramic…

Computer Vision and Pattern Recognition · Computer Science 2024-09-09 Hocine Kadi , Théo Sourget , Marzena Kawczynski , Sara Bendjama , Bruno Grollemund , Agnès Bloch-Zupan

Peridynamics is a nonlocal generalization of continuum mechanics theory which adresses discontinuous problems without using partial derivatives and replacing its by an integral operator. As a consequence, it finds applications in the…

Numerical Analysis · Mathematics 2022-09-07 Luciano Lopez , Sabrina Francesca Pellegrino

One of the major challenges of contemporary mathematics is numerical solving of various problems for functional differential equations (FDE), in particular Cauchy problem for delayed and neutral differential equations. Recently large…

Classical Analysis and ODEs · Mathematics 2019-01-09 Josef Rebenda , Zdeněk Šmarda , Yasir Khan

The Voronoi diagram-based dual-front active contour models are known as a powerful and efficient way for addressing the image segmentation and domain partitioning problems. In the basic formulation of the dual-front models, the evolving…

Computer Vision and Pattern Recognition · Computer Science 2021-06-09 Da Chen , Jack Spencer , Jean-Marie Mirebeau , Ke Chen , Minglei Shu , Laurent D. Cohen

This letter introduces a dual application of denoising diffusion probabilistic model (DDPM)-based channel estimation algorithm integrating data denoising and augmentation. Denoising addresses the severe noise in raw signals at pilot…

Signal Processing · Electrical Eng. & Systems 2025-10-06 Yupeng Li , Ruhao Zhang , Yitong Liu , Chunju Shao , Jing Jin , Shijian Gao

We introduce a new approach to the modelling of the light distribution of galaxies, an orthonormal polar base formed by a combination of Chebyshev rational functions and Fourier polynomials that we call CHEF functions, or CHEFs. We have…

Instrumentation and Methods for Astrophysics · Physics 2015-05-27 Y. Jiménez-Teja , N. Benítez

We develop a sparse spectral method for a class of fractional differential equations, posed on $\mathbb{R}$, in one dimension. These equations can include sqrt-Laplacian, Hilbert, derivative and identity terms. The numerical method utilizes…

Numerical Analysis · Mathematics 2024-06-12 Ioannis P. A. Papadopoulos , Sheehan Olver

Deep learning methods have played a more and more important role in hyperspectral image classification. However, the general deep learning methods mainly take advantage of the information of sample itself or the pairwise information between…

Computer Vision and Pattern Recognition · Computer Science 2021-03-30 Zhiqiang Gong , Weidong Hu , Xiaoyong Du , Ping Zhong , Panhe Hu

We derive a priori error estimates for Nitsche's method applied to elliptic problems on approximate domains. Such approximations arise, for example, in unfitted finite element methods, data-driven simulations, and evolving domain problems,…

Numerical Analysis · Mathematics 2026-04-02 Mats G. Larson , Karl Larsson , Shantiram Mahata