Results 81 to 90 of about 32,100 (199)

Inference on Common Trends in a Cointegrated Nonlinear SVAR

Oxford Bulletin of Economics and Statistics, EarlyView.
ABSTRACT We consider the problem of performing inference on the number of common stochastic trends when data is generated by a cointegrated CKSVAR (a two‐regime, piecewise affine SVAR; Mavroeidis, 2021), using a modified version of the Breitung (2002) multivariate variance ratio test that is robust to the presence of nonlinear cointegration (of a known
James A. Duffy, Xiyu Jiao
wiley   +1 more source

Self‐Similar Blowup for the Cubic Schrödinger Equation

Communications on Pure and Applied Mathematics, Volume 79, Issue 8, Page 1831-1918, August 2026.
ABSTRACT We give a rigorous proof for the existence of a finite‐energy, self‐similar solution to the focusing cubic Schrödinger equation in three spatial dimensions. The proof is computer‐assisted and relies on a fixed point argument that shows the existence of a solution in the vicinity of a numerically constructed approximation.
Roland Donninger, Birgit Schörkhuber
wiley   +1 more source

Is It Easier to Count Communities Than Find Them?

Random Structures &Algorithms, Volume 68, Issue 4, July 2026.
ABSTRACT Random graph models with community structure have been studied extensively in the literature. For both the problems of detecting and recovering community structure, an interesting landscape of statistical and computational phase transitions has emerged. A natural unanswered question is: Might it be possible to infer properties of the community
Cynthia Rush, Fiona Skerman, Alexander S. Wein, Dana Yang   +3 more
wiley   +1 more source

Two modified shifted Chebyshev–Galerkin operational matrix methods for even-order partial boundary value problems

Boundary Value Problems
This paper presents two operational matrices. The first one represents integer-order derivatives of the modified shifted Chebyshev polynomials of the second kind.
M. Abdelhakem, Dina Abdelhamied, M. El-Kady, Y. H. Youssri   +3 more
doaj   +1 more source

A numerical solution of time-fractional coupled Korteweg-de Vries equation by using spectral collection method

Ain Shams Engineering Journal, 2018
In this paper, we present a numerical method proficient for solving a system of time–fractional partial differential equations. For this sake, we use spectral collection method based on shifted Chebyshev polynomials in space and finite difference method ...
Basim Albuohimad, Hojatollah Adibi, Saeed Kazem   +2 more
doaj   +1 more source

RAMS: Residual‐Based Adversarial‐Gradient Moving Sample Method for Scientific Machine Learning in Solving Partial Differential Equations

Advanced Intelligent Discovery, Volume 2, Issue 3, June 2026.
We propose a residual‐based adversarial‐gradient moving sample (RAMS) method for scientific machine learning that treats samples as trainable variables and updates them to maximize the physics residual, thereby effectively concentrating samples in inadequately learned regions.
Weihang Ouyang, Min Zhu, Wei Xiong, Si‐Wei Liu, Lu Lu   +4 more
wiley   +1 more source

Elastoplasticity Informed Kolmogorov–Arnold Networks Using Chebyshev Polynomials

International Journal for Numerical and Analytical Methods in Geomechanics, Volume 50, Issue 8, Page 3331-3354, 10 June 2026.
ABSTRACT Multilayer perceptron (MLP) networks are predominantly used to develop data‐driven constitutive models for granular materials. They offer a compelling alternative to traditional physics‐based constitutive models in predicting non‐linear responses of these materials, for example, elastoplasticity, under various loading conditions. To attain the
Farinaz Mostajeran, Salah A. Faroughi
wiley   +1 more source

Collocation Method via Jacobi Polynomials for Solving Nonlinear Ordinary Differential Equations

International Journal of Mathematics and Mathematical Sciences, 2011
We extend a collocation method for solving a nonlinear ordinary differential equation (ODE) via Jacobi polynomials. To date, researchers usually use Chebyshev or Legendre collocation method for solving problems in
Ahmad Imani, Azim Aminataei, Ali Imani
doaj   +1 more source

Fast algorithm and new potential formula represented by Chebyshev polynomials for an [Formula: see text] globe network. [PDF]

Sci Rep, 2022
Zhou Y, Zheng Y, Jiang X, Jiang Z.
europepmc   +1 more source

Optimal Control‐Based Generic Framework for Radiofrequency Pulse Design in MRI

NMR in Biomedicine, Volume 39, Issue 6, June 2026.
This paper presents an open‐source Python‐based optimal control RF design framework, which can tackle various problems (short‐T2 selective excitation or B1‐robust excitation/inversion). It features three main methodological contributions: a specific cost is introduced to reduce pulse peak amplitude; consistent integration of various hard constraints on
Emilio Molina, Hélène Ratiney, Eric Van Reeth   +2 more
wiley   +1 more source