Browsing by Author "Hafez, R. M."

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A Computationally Efficient Method For a Class of Fractional Variational and Optimal Control Problems Using Fractional Gegenbauer Functions
(Editura Academiei Romane, 2018) El-Kalaawy, Ahmed A.; Doha, Eid H.; Ezz-Eldien, Samer S.; Abdelkawy, M. A.; Hafez, R. M.; Amin, A. Z. M.; Baleanu, Dumitru; Zaky, M. A.; 56389
This paper is devoted to investigate, from the numerical point of view, fractional-order Gegenbauer functions to solve fractional variational problems and fractional optimal control problems. We first introduce an orthonormal system of fractional-order Gegenbauer functions. Then, a formulation for the fractional-order Gegenbauer operational matrix of fractional integration is constructed. An error upper bound for the operational matrix of the fractional integration is also given. The properties of the fractional-order Gegenbauer functions are utilized to reduce the given optimization problems to systems of algebraic equations. Some numerical examples are included to demonstrate the efficiency and the accuracy of the proposed approach.
Citation Count: Bhrawy, AH...et.al. (2015). "A highly accurate Jacobi collocation algorithm for systems of high-order linear differential-difference equations with mixed initial conditions" Mathematical Methods In The Applied Sciences, Vol.38, No.14, pp.3022-3032.
A highly accurate Jacobi collocation algorithm for systems of high-order linear differential-difference equations with mixed initial conditions
(Wiley, 2015) Bhrawy, A. H.; Doha, E. H.; Baleanu, Dumitru; Hafez, R. M.; 56389
In this paper, a shifted Jacobi-Gauss collocation spectral algorithm is developed for solving numerically systems of high-order linear retarded and advanced differential-difference equations with variable coefficients subject to mixed initial conditions. The spatial collocation approximation is based upon the use of shifted Jacobi-Gauss interpolation nodes as collocation nodes. The system of differential-difference equations is reduced to a system of algebraic equations in the unknown expansion coefficients of the sought-for spectral approximations. The convergence is discussed graphically. The proposed method has an exponential convergence rate. The validity and effectiveness of the method are demonstrated by solving several numerical examples. Numerical examples are presented in the form of tables and graphs to make comparisons with the results obtained by other methods and with the exact solutions more easier.
Citation Count: Doha, E.H...et al. (2014). "A Jacobi Collocation Method for Troesch'S Problem in Plasma Physics", Proceedings of the Romanian Academy Series A - Mathematics Physics Technical Sciences Information Science, Vol. 15, No. 2, pp. 130-138.
A Jacobi Collocation Method for Troesch'S Problem in Plasma Physics
(Editura Academiei Romane, 2014) Doha, Eid. H.; Baleanu, Dumitru; Bhrawy, A. H.; Hafez, R. M.; 56389
In this paper, we propose a numerical approach for solving Troesch's problem which arises in the confinement of a plasma column by radiation pressure. It is also an inherently unstable two-point boundary value problem. The spatial approximation is based on shifted Jacobi-Gauss collocation method in which the shifted Jacobi-Gauss points are used as collocation nodes. The results presented here demonstrate reliability and efficiency of the method.
Citation Count: Hafez, R.M...et al. (2015). A Jacobi Gauss-Lobatto and Gauss-Radau collocation algorithm for solving fractional Fokker-Planck equations. Nonlinear Dynamics, 82(3), 1431-1440. http://dx.doi.org/10.1007/s11071-015-2250-7
A Jacobi Gauss-Lobatto and Gauss-Radau collocation algorithm for solving fractional Fokker-Planck equations
(Springer, 2015) Hafez, R. M.; Ezz-Eldien, Samer S.; Bhrawy, Ali H.; Ahmed, Engy A.; Baleanu, Dumitru
In this article, we construct a new numerical approach for solving the time-fractional Fokker-Planck equation. The shifted Jacobi polynomials are used as basis functions, and the fractional derivative is described in the sense of Caputo. The proposed approach is a combination of shifted Jacobi Gauss-Lobatto scheme for the spatial discretization and the shifted Jacobi Gauss-Radau scheme for temporal approximation. The problem is then reduced to a problem consisting of a system of algebraic equations that greatly simplifies the problem. In addition, our numerical algorithm is also applied for solving the space-fractional Fokker-Planck equation and the time-space-fractional Fokker-Planck equation. Numerical results are consistent with the theoretical analysis, indicating the high accuracy and effectiveness of the proposed algorithm
A New Jacobi Rational-Gauss Collocation Method For Numerical Solution of Generalized Pantograph Equations
(Elsevier, 2014) Doha, E. H.; Bhrawy, A. H.; Baleanu, Dumitru; Hafez, R. M.; 56389
This paper is concerned with a generalization of a functional differential equation known as the pantograph equation which contains a linear functional argument. In this article, a new spectral collocation method is applied to solve the generalized pantograph equation with variable coefficients on a semi-infinite domain. This method is based on Jacobi rational functions and Gauss quadrature integration. The Jacobi rational-Gauss method reduces solving the generalized pantograph equation to a system of algebraic equations. Reasonable numerical results are obtained by selecting few Jacobi rational-Gauss collocation points. The proposed Jacobi rational-Gauss method is favorably compared with other methods. Numerical results demonstrate its accuracy, efficiency, and versatility on the half-line. (C) 2013 IMACS. Published by Elsevier B.V. All rights reserved.
A Pseudospectral Algorithm for Solving Multipantograph Delay Systems on a Semi-Infinite Interval Using Legendre Rational Functions
(Hindawi LTD, 2014) Doha, E. H.; Baleanu, Dumitru; Bhrawy, A. H.; Hafez, R. M.; 56389
A new Legendre rational pseudospectral scheme is proposed and developed for solving numerically systems of linear and nonlinear multipantograph equations on a semi-infinite interval. A Legendre rational collocation method based on Legendre rational- Gauss quadrature points is utilized to reduce the solution of such systems to systems of linear and nonlinear algebraic equations. In addition, accurate approximations are achieved by selecting few Legendre rational- Gauss collocation points. The numerical results obtained by this method have been compared with various exact solutions in order to demonstrate the accuracy and efficiency of the proposed method. Indeed, for relatively limited nodes used, the absolute error in our numerical solutions is sufficiently small.
Citation Count: Doha, E.H...et al. (2015). An efficient numerical scheme based on the shifted orthonormal Jacobi polynomials for solving fractional optimal control problems. Advance in Difference Equations. http://dx.doi.org/10.1186/s13662-014-0344-z
An efficient numerical scheme based on the shifted orthonormal Jacobi polynomials for solving fractional optimal control problems
(Springer International Publishing, 2015) Doha, Eid H.; Bhrawy, Ali H.; Baleanu, Dumitru; Ezz-Eldien, Samer S.; Hafez, R. M.
In this article, we introduce a numerical technique for solving a general form of the fractional optimal control problem. Fractional derivatives are described in the Caputo sense. Using the properties of the shifted Jacobi orthonormal polynomials together with the operational matrix of fractional integrals (described in the Riemann-Liouville sense), we transform the fractional optimal control problem into an equivalent variational problem that can be reduced to a problem consisting of solving a system of algebraic equations by using the Legendre-Gauss quadrature formula with the Rayleigh-Ritz method. This system can be solved by any standard iteration method. For confirming the efficiency and accuracy of the proposed scheme, we introduce some numerical examples with their approximate solutions and compare our results with those achieved using other methods.
Citation Count: Doha, E. H...et.al. (2017). "Composite Bernoulli-Laguerre collocation method for a class of hyperbolic telegraph-type equations", Romanian Reports In Physics, Vol.69, No.4.
Composite Bernoulli-Laguerre collocation method for a class of hyperbolic telegraph-type equations
(Editura Academiei Romane, 2017) Doha, E. H.; Hafez, R. M.; Abdelkawy, M. A.; Ezz-Eldien, S. S.; Taha, T. M.; Zaky, M. A.; Amin, A. Z. M.; El-Kalaawy, A. A.; Baleanu, Dumitru; 56389
In this work, we introduce an efficient Bernoulli-Laguerre collocation method for solving a class of hyperbolic telegraph-type equations in one dimension. Bernoulli and Laguerre polynomials and their properties are utilized to reduce the aforementioned problems to systems of algebraic equations. The proposed collocation method, both in spatial and temporal discretizations, is successfully developed to handle the two-dimensional case. In order to highlight the effectiveness of our approachs, several numerical examples are given. The approximation techniques and results developed in this paper are appropriate for many other problems on multiple-dimensional domains, which are not of standard types.
Efficient Jacobi-Gauss Collocation Method for Solving Initial Value Problems of Bratu Type
(Pleiades Publishing INC, 2013) Doha, E. H.; Bhrawy, A. H.; Baleanu, Dumitru; Hafez, R. M.; 56389
In this paper, we propose the shifted Jacobi-Gauss collocation spectral method for solving initial value problems of Bratu type, which is widely applicable in fuel ignition of the combustion theory and heat transfer. The spatial approximation is based on shifted Jacobi polynomials J(n)((alpha, beta))(x) with alpha, beta is an element of (-1, infinity), x is an element of [0, 1] and n the polynomial degree. The shifted Jacobi-Gauss points are used as collocation nodes. Illustrative examples have been discussed to demonstrate the validity and applicability of the proposed technique. Comparing the numerical results of the proposed method with some well-known results show that the method is efficient and gives excellent numerical results.
Citation Count: Bhrawy, A.H...et al. (2015). Generalized Laguerre-Gauss-Radau scheme for first order hyperbolic equations on semi-infinite domains. Romanian Journal of Physics, 60(7-8), 918-934.
Generalized Laguerre-Gauss-Radau scheme for first order hyperbolic equations on semi-infinite domains
(Editura Academiei Romane, 2015) Bhrawy, A. H.; Hafez, R. M.; Alzahrani, Ebraheem; Baleanu, Dumitru; Alzahrani, A. A.
In this article, we develop a numerical approximation for first-order hyperbolic equations on semi-infinite domains by using a spectral collocation scheme. First, we propose the generalized Laguerre-Gauss-Radau collocation scheme for both spatial and temporal discretizations. This in turn reduces the problem to the obtaining of a system of algebraic equations. Second, we use a Newton iteration technique to solve it. Finally, the obtained results are compared with the exact solutions, highlighting the performance of the proposed numerical method.
Citation Count: Ezz-Eldien, Samer S... et.al. (2017). "New numerical approach for fractional variational problems using shifted legendre orthonormal polynomials", Journal Of Optimization Theory And Applications, Vol.174, No.1, pp.295-320.
New numerical approach for fractional variational problems using shifted legendre orthonormal polynomials
(Springer/Plenum Publishers, 2017) Ezz-Eldien, Samer S.; Hafez, R. M.; Bhrawy, Ali H.; Baleanu, Dumitru; El-Kalaawy, Ahmed A.; 56389
This paper reports a new numerical approach for numerically solving types of fractional variational problems. In our approach, we use the fractional integrals operational matrix, described in the sense of Riemann-Liouville, with the help of the Lagrange multiplier technique for converting the fractional variational problem into an easier problem that consisting of solving an algebraic equations system in the unknown coefficients. Several numerical examples are introduced, combined with their approximate solutions and comparisons with other numerical approaches, for confirming the accuracy and applicability of the proposed approach.
Citation Count: Hafez, R. M...et al. (20179. "Numerical solutions of two-dimensional mixed volterra-fredholm integral equations via bernoulli collocation method", Romanian Journal Of Physics, Vol. 62, No. 3-4.
Numerical solutions of two-dimensional mixed volterra-fredholm integral equations via bernoulli collocation method
(Editura Academiei Romane, 2017) Hafez, R. M.; Doha, E. H.; Bhrawy, A. H.; Baleanu, Dumitru; 56389
The mixed Volterra-Fredholm integral equations (VFIEs) arise in various physical and biological models. The main purpose of this article is to propose and analyze efficient Bernoulli collocation techniques for numerically solving classes of two-dimensional linear and nonlinear mixed VFIEs. The novel aspect of the technique is that it reduces the problem under consideration to a system of algebraic equations by using the Gauss-Bernoulli nodes. One of the main advantages of the present approach is its superior accuracy. Consequently, good results can be obtained even by using a relatively small number of collocation nodes. In addition, several numerical results are given to illustrate the features of the proposed technique.