Results 21 to 30 of about 18,388 (125)

Equations of motion in General Relativity and Quantum Mechanics

open access: yes, 2011
In a previous article a relationship was established between the linearized metrics of General Relativity associated with geodesics and the Dirac Equation of quantum mechanics.
O'Hara, Paul
core   +1 more source

Fast Calculation for the Flow and Heat Transfer of Tempered Fractional Maxwell Viscoelastic Fluid

open access: yesInternational Journal for Numerical Methods in Fluids, EarlyView.
This study develops a tempered fractional Maxwell model to simulate unsteady thermal flow in viscoelastic fluids, capturing key rheological behaviors. A fast SOE‐based algorithm is proposed to improve the computational efficiency of the numerical scheme. Results reveal how key parameters influence fluid motion and heat transfer, demonstrating the model'
Yi Liu, Mochen Jiang, Libo Feng
wiley   +1 more source

Direct Numerical Simulation of Magnetohydrodynamic Slip‐Flow Past a Stretching Surface Using Physics‐Informed Neural Network

open access: yesHeat Transfer, EarlyView.
ABSTRACT Traditional numerical methods, such as finite difference methods (FDM), finite element methods (FEM), and spectral methods, often face meshing challenges and high computational cost for solving nonlinear coupled differential equations. Machine learning techniques, specifically Physics‐informed machine learning, address these obstacles by ...
Ahmad, Feroz Soomro, Husna Zafar
wiley   +1 more source

Optimal Homogeneous ℒp$$ {\boldsymbol{\mathcal{L}}}_{\boldsymbol{p}} $$‐Gain Controller

open access: yesInternational Journal of Robust and Nonlinear Control, EarlyView.
ABSTRACT Nonlinear ℋ∞$$ {\mathscr{H}}_{\infty } $$‐controllers are designed for arbitrarily weighted, continuous homogeneous systems with a focus on systems affine in the control input. Based on the homogeneous ℒp$$ {\mathcal{L}}_p $$‐norm, the input–output behavior is quantified in terms of the homogeneous ℒp$$ {\mathcal{L}}_p $$‐gain as a ...
Daipeng Zhang   +3 more
wiley   +1 more source

Hamiltonian constraint formulation of classical field theories

open access: yes, 2016
Classical field theory is considered as a theory of unparametrized surfaces embedded in a configuration space, which accommodates, in a symmetric way, spacetime positions and field values.
Zatloukal, Vaclav
core   +1 more source

Optimal Gain Selection for the Arbitrary‐Order Homogeneous Differentiator

open access: yesInternational Journal of Robust and Nonlinear Control, EarlyView.
ABSTRACT Differentiation of noisy signals is a relevant and challenging task. Widespread approaches are the linear high‐gain observer acting as a differentiator and Levant's robust exact differentiator with a discontinuous right‐hand side. We consider the family of arbitrary‐order homogeneous differentiators, which includes these special cases.
Benjamin Calmbach   +2 more
wiley   +1 more source

Reduction theory and the Lagrange–Routh equations [PDF]

open access: yes, 2000
Reduction theory for mechanical systems with symmetry has its roots in the classical works in mechanics of Euler, Jacobi, Lagrange, Hamilton, Routh, Poincaré, and others.
Marsden, Jerrold E.   +2 more
core   +2 more sources

Synthesizing Interacting Model‐Based Optimal Control and Model‐Free Learning Approaches for Nonlinear Systems

open access: yesInternational Journal of Robust and Nonlinear Control, EarlyView.
ABSTRACT In this paper, we consider the optimal control problem for an unknown continuous‐time nonlinear system, and present a framework that integrates model‐based and model‐free methods to solve it. Each approach offers distinct advantages: model‐based techniques provide offline synthesis and data efficiency, while model‐free procedures excel at ...
Surabhi Athalye   +2 more
wiley   +1 more source

Differential Galois Theory and Hopf Algebras for Lie Pseudogroups

open access: yesAxioms
According to a clever but rarely quoted or acknowledged work of E. Vessiot that won the prize of the Académie des Sciences in 1904, “Differential Galois Theory” (DGT) has mainly to do with the study of “Principal Homogeneous Spaces” (PHSs) for finite ...
Jean-Francois Pommaret
doaj   +1 more source

Key Technical Fields and Future Outlooks of Space Manipulators: A Survey

open access: yesSmartBot, EarlyView.
This paper systematically reviews the technological development of space manipulators, emphasizing the unique challenges posed by space environments. It examines four areas: structural design, modeling, planning, and control, while introducing typical ground test platforms.
Gang Chen   +12 more
wiley   +1 more source

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