نتایج جستجو برای: letnikov derivative

تعداد نتایج: 63778  

2017
Ashutosh Bist Swati Sondhi

Underwater images usually suffer from degraded visibility. Light attenuates and scatters in water resulting in low contrast and haziness in the scenes. Therefore, the main problems to be dealt with in underwater environment are poor contrast, non-uniform lighting, haziness and blurring. Hence, in order to study underwater images, it becomes utmost important to extract the invisible or unclear e...

Journal: :Fractal and fractional 2021

In this paper, wave propagation is considered in a medium described by fractional-order model, which formulated with the use of two-sided fractional derivative Ortigueira and Machado. Although relation to causality clearly specified its definition, there no obvious between transfer function induced derivative. Hence, system investigated; output an electromagnetic signal propagating media time-d...

Journal: : 2022

Tumor diseases have killed many people around the world for centuries. For this purpose, a lot of scientists analyzed immune system’s cells in order to cope with tumor growths living beings. reason, we examine system reflecting relationship between and growth study. This is handled traditional Caputo fractional derivative. We give stability analysis equilibrium points solution properties system...

2016
Nikita Markov Konstantin Ushenin Ahmed Hendy

Space fractional derivatives have been used instead of integer operators with success in a variety of practical applications to study and describe transport processes in media characterized by spatial connectivity properties and high structural heterogeneity altering the classical laws of diffusion. This study provides an implementation of space fractional FitzHugh-Nagumo model of excitable med...

2002
Ivo PETRÁŠ Blas M. VINAGRE Ľubomír DORČÁK Vincent FELIU

The purpose of this paper is to make a contribution for solving one of the major drawbacks for using fractional controllers: the controller implementation. In digital form, this is usually done by using a truncated version of the Grundwald-Letnikov formula for fractional derivative. In this work, experimental results are given comparing this method for digital implementation of a fractional PD ...

Journal: :Advances in parallel computing 2021

At present, fractional differential is the effective mathematical approach which deals with factual problems. This projected technique employs derivatives definitions Riemann-Liouville (R-L), Grunwald-Letnikov (G-L) and caputo for denoising medical image. The presented method based on derivative in turn improves quality of input image processed integer order such as pre-processing operation, co...

Journal: :Mathematical Control and Related Fields 2021

In this paper, we study optimal control problems for nonlinear fractional order boundary value on a star graph, where the derivative is described in Caputo sense. The adjoint state and optimality system are derived problem (FOCP) by using Lagrange multiplier method. Then, existence uniqueness of solution equation proved means Banach contraction principle. We also pr...

2016
Nasser H. Sweilam Seham M. AL-Mekhlafi

In this paper, we presented a novel multi-strain TB model of variable-order fractional derivatives, which incorporates three strains: drug-sensitive, emerging multi-drug resistant (MDR) and extensively drug-resistant (XDR), as an extension for multi-strain TB model of nonlinear ordinary differential equations which developed in 2014 by Arino and Soliman [1]. Numerical simulations for this varia...

Journal: :Arab journal of basic and applied sciences 2023

An optimal control problem for the variable-order fractional-integer mathematical model of vaccination Covid 19 is presented in this research, where order derivatives varies during course time interval, becoming fractional or classical when it more favourable. The are defined here using both integral Riemann–Liouville and Caputo derivative. existence, uniqueness, boundedness positivity solution...

Journal: :CoRR 2018
Yiran Xu Jingye Li Guofei Pang Zhikai Wang Xiaohong Chen

Decoupled fractional Laplacian wave equation can describe the seismic wave propagation in attenuating media. Fourier pseudospectral implementations, which solve the equation in spatial frequency domain, are the only existing methods for solving the equation. For the earth media with curved boundaries, the pseudospectral methods could be less attractive to handle the irregular computational doma...

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