Results 61 to 70 of about 11,949,866 (380)

Effect of Foot Orthoses on Midfoot Pain and the Volume of Bone Marrow Lesions in the Midfoot: A Randomized Mechanism of Action Study

open access: yesArthritis Care &Research, EarlyView.
Objective Foot orthoses are thought to improve pain by potentially modifying internal mechanical forces. To test this, we explored whether foot orthoses can modify patterns of bone marrow lesions (BMLs) in people with midfoot pain. Methods Forty‐two people were recruited with midfoot pain, and magnetic resonance imaging–confirmed midfoot BMLs ...
Jill Halstead   +4 more
wiley   +1 more source

Squares and difference sets in finite fields [PDF]

open access: yes, 2013
For infinitely many primes p = 4k+1 we give a slightly improved upper bound for the maximal cardinality of a set B ⊂ Z p such that the difference set B−B contains only quadratic residues. Namely, instead of the ”trivial” bound |B| ≤ √p we prove |B √p
Bachoc, C.   +2 more
core  

A Q‐Learning Algorithm to Solve the Two‐Player Zero‐Sum Game Problem for Nonlinear Systems

open access: yesInternational Journal of Adaptive Control and Signal Processing, Volume 39, Issue 3, Page 566-581, March 2025.
A Q‐learning algorithm to solve the two‐player zero‐sum game problem for nonlinear systems. ABSTRACT This paper deals with the two‐player zero‐sum game problem, which is a bounded L2$$ {L}_2 $$‐gain robust control problem. Finding an analytical solution to the complex Hamilton‐Jacobi‐Issacs (HJI) equation is a challenging task.
Afreen Islam   +2 more
wiley   +1 more source

Hopfield Neural Networks for Online Constrained Parameter Estimation With Time‐Varying Dynamics and Disturbances

open access: yesInternational Journal of Adaptive Control and Signal Processing, EarlyView.
This paper proposes two projector‐based Hopfield neural network (HNN) estimators for online, constrained parameter estimation under time‐varying data, additive disturbances, and slowly drifting physical parameters. The first is a constraint‐aware HNN that enforces linear equalities and inequalities (via slack neurons) and continuously tracks the ...
Miguel Pedro Silva
wiley   +1 more source

An Adaptive Human Pilot Model With Reaction Time Delay for Enhanced Adaptive Control in Piloted Systems

open access: yesInternational Journal of Adaptive Control and Signal Processing, EarlyView.
This work introduces an adaptive human pilot model that captures pilot time‐delay effects in adaptive control systems. The model enables the prediction of pilot–controller interactions, facilitating safer integration and improved design of adaptive controllers for piloted applications.
Abdullah Habboush, Yildiray Yildiz
wiley   +1 more source

Weak solvability of the unconditionally stable difference scheme for the coupled sine-Gordon system

open access: yesNonlinear Analysis, 2020
In this paper, we study the existence and uniqueness of weak solution for the system of finite difference schemes for coupled sine-Gordon equations. A novel first order of accuracy unconditionally stable difference scheme is considered.
Ozgur Yildirim, Meltem Uzun
doaj   +1 more source

Bistable Mechanisms 3D Printing for Mechanically Programmable Vibration Control

open access: yesAdvanced Engineering Materials, EarlyView.
This work introduces a 3D‐printed bistable mechanism integrated into tuned mass dampers (TMDs) for mechanically adaptive passive vibration suppression. Through optimized geometry, the bistable design provides adaptable vibration reduction across a broad range of scenarios, achieving effective vibration mitigation without complex controls or external ...
Ali Zolfagharian   +4 more
wiley   +1 more source

Geometric Optimization and Mechanical Performance Enhancement of Auxetic Structures for High‐Impact Applications Through Fused Deposition Modeling

open access: yesAdvanced Engineering Materials, EarlyView.
This study explores the mechanical performance of three auxetic structures, identifying a re‐entrant‐star hybrid as the most effective for impact absorption. Finite element simulations and experiments demonstrate significant gains in energy absorption and flexural strength after geometric optimization. This study investigates the mechanical performance
Malik Hassan   +4 more
wiley   +1 more source

Symmetrizable finite difference operators [PDF]

open access: yesMathematics of Computation, 1990
We introduce the notion of a symmetrizable finite difference operator and prove that such operators are stable. We then present some sufficient conditions for symmetrizability. One of these extends H.-O. Kreiss’ theorem on dissipative difference schemes for hyperbolic equations to a more general case with full (x, t)-variable coefficients.
openaire   +2 more sources

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