K. Maleknejad and H. Mesgarani
Aims to present a boundary integral equation method for solving Laplace's equation Δu=0 with nonlinear boundary conditions.
Abstract
Purpose
Aims to present a boundary integral equation method for solving Laplace's equation Δu=0 with nonlinear boundary conditions.
Design/methodology/approach
The nonlinear boundary value problem is reformulated as a nonlinear boundary integral equation, with u on the boundary as the solution being sought. The integral equation is solved numerically by using the collocation method on smooth or nonsmooth boundary; the singularities of solution degrade the rates of convergence.
Findings
Variants of the methods for finding numerical solutions are suggested. So these methods have been compared with respect to number of iterations.
Practical implications
Numerical experiments show the efficiency of the proposed methods.
Originality/value
Provides new methods to solve nonlinear weakly singular integral equations and discusses difficulties that arise in particular cases.
Details
Keywords
K. Maleknejad, M. Tavassoli Kajani and Y. Mahmoudi
Uses the continuous Legendre wavelets on the interval [0,1) in the manner of M. Razzaghi and S. Yousefi, to solve the linear second kind integral equations. We use quadrature…
Abstract
Uses the continuous Legendre wavelets on the interval [0,1) in the manner of M. Razzaghi and S. Yousefi, to solve the linear second kind integral equations. We use quadrature formula for the calculation of inner products of any functions, which are required in the approximation for the integral equations. Then, we reduced the integral equation to the solution of linear algebraic equations.
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Keywords
K. Maleknejad, M. Alizadeh and R. Mollapourasl
The purpose of this paper is to discuss a numerical method for solving Fredholm integral equations of the first kind with degenerate kernels and convergence of this numerical…
Abstract
Purpose
The purpose of this paper is to discuss a numerical method for solving Fredholm integral equations of the first kind with degenerate kernels and convergence of this numerical method.
Design/methodology/approach
By using sinc collocation method in strip, the authors try to estimate a numerical solution for this kind of integral equation.
Findings
Some numerical results support the accuracy and efficiency of the stated method.
Originality/value
The paper presents a method for solving first kind integral equations which are ill‐posed.
Details
Keywords
Mohsen Rabbani and Khosrow Maleknejad
The purpose of this paper is to use Alpert wavelet basis and modify the integrand function approximation coefficients to solve Fredholm‐Hammerstein integral equations.
Abstract
Purpose
The purpose of this paper is to use Alpert wavelet basis and modify the integrand function approximation coefficients to solve Fredholm‐Hammerstein integral equations.
Design/methodology/approach
L2[0, 1] was considered as solution space and the solution was projected to the subspaces of L2[0, 1] with finite dimension so that basis elements of these subspaces were orthonormal.
Findings
In this process, solution of Fredholm‐Hammerstein integral equation is found by solving the generated system of nonlinear equations.
Originality/value
Comparing the method with others shows that this system has less computation. In fact, decreasing of computations result from the modification.
Details
Keywords
Mohsen Rabbani and Khosrow Maleknejad
The purpose of this paper is to explain the choice of Alpert multi‐wavelet as basis functions to discrete Fredholm integral equation of the second kind by using Petrov‐Galerkin…
Abstract
Purpose
The purpose of this paper is to explain the choice of Alpert multi‐wavelet as basis functions to discrete Fredholm integral equation of the second kind by using Petrov‐Galerkin method.
Design/methodology/approach
In this process, two kinds of matrices are obtained from inner product between basis of test space and trial space; some of them are diagonal with positive elements and some others are invertible. These matrices depend on type of selection of test and trial space basis.
Findings
In this process, solution of Fredholm integral equation of the second kind is found by solving the generated system of linear equations.
Originality/value
In previous work, convergence of Petrov‐Galerkin method has been discussed with some restrictions on degrees of chosen polynomial basis, but in this paper convergence is obtained for every degree. In point of computation, because of appearance of diagonal and invertible matrices, a small dimension system with a more accurate solution is obtained. The numerical examples illustrate these facts.
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Keywords
Elçin Yusufoğlu and Barış Erbaş
This paper sets out to introduce a numerical method to obtain solutions of Fredholm‐Volterra type linear integral equations.
Abstract
Purpose
This paper sets out to introduce a numerical method to obtain solutions of Fredholm‐Volterra type linear integral equations.
Design/methodology/approach
The flow of the paper uses well‐known formulations, which are referenced at the end, and tries to construct a new approach for the numerical solutions of Fredholm‐Volterra type linear equations.
Findings
The approach and obtained method exhibit consummate efficiency in the numerical approximation to the solution. This fact is illustrated by means of examples and results are provided in tabular formats.
Research limitations/implications
Although the method is suitable for linear equations, it may be possible to extend the approach to nonlinear, even to singular, equations which are the future objectives.
Practical implications
In many areas of mathematics, mathematical physics and engineering, integral equations arise and most of these equations are only solvable in terms of numerical methods. It is believed that the method is applicable to many problems in these areas such as loads in elastic plates, contact problems of two surfaces, and similar.
Originality/value
The paper is original in its contents, extends the available work on numerical methods in the solution of certain problems, and will prove useful in real‐life problems.
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Keywords
Khosrow Maleknejad, Saeed Sohrabi and Yasser Rostami
The purpose of this paper, with reference to compression of different images' portions with various qualities, is to obtain a high‐compression coefficient.
Abstract
Purpose
The purpose of this paper, with reference to compression of different images' portions with various qualities, is to obtain a high‐compression coefficient.
Design/methodology/approach
Usually, not all parts of a medical image have equal significance. Also, an image's background can be combined with noise. This method separates a part of the video which is moving from a part that is stationary.
Findings
This process results in the high‐quality compression of medical frames.
Originality/value
Separating parts of a frame using 2D and 3D wavelet transform makes a valuable contribution to biocybernetics.
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Keywords
The purpose of this study is to obtain a scheme for the numerical solution of Volterra integro-differential equations with time periodic coefficients deduced from the charged…
Abstract
Purpose
The purpose of this study is to obtain a scheme for the numerical solution of Volterra integro-differential equations with time periodic coefficients deduced from the charged particle motion for certain configurations of oscillating magnetic fields.
Design/methodology/approach
The method reduces the solution of these types of integro-differential equations to the solution of two-dimensional Volterra integral equations of the second kind. The new method uses the discrete collocation method together with thin plate splines constructed on a set of scattered points as a basis.
Findings
The scheme can be easily implemented on a computer and has a computationally attractive algorithm. Numerical examples are included to show the validity and efficiency of the new technique.
Originality/value
The author uses thin plate splines as a type of free-shape parameter radial basis functions which establish an effective and stable method to solve electromagnetic integro-differential equations. As the scheme does not need any background meshes, it can be identified as a meshless method.
Details
Keywords
This paper aims to propose an efficient and convenient numerical algorithm for two-dimensional nonlinear Volterra-Fredholm integral equations and fractional integro-differential…
Abstract
Purpose
This paper aims to propose an efficient and convenient numerical algorithm for two-dimensional nonlinear Volterra-Fredholm integral equations and fractional integro-differential equations (of Hammerstein and mixed types).
Design/methodology/approach
The main idea of the presented algorithm is to combine Bernoulli polynomials approximation with Caputo fractional derivative and numerical integral transformation to reduce the studied two-dimensional nonlinear Volterra-Fredholm integral equations and fractional integro-differential equations to easily solved algebraic equations.
Findings
Without considering the integral operational matrix, this algorithm will adopt straightforward discrete data integral transformation, which can do good work to less computation and high precision. Besides, combining the convenient fractional differential operator of Bernoulli basis polynomials with the least-squares method, numerical solutions of the studied equations can be obtained quickly. Illustrative examples are given to show that the proposed technique has better precision than other numerical methods.
Originality/value
The proposed algorithm is efficient for the considered two-dimensional nonlinear Volterra-Fredholm integral equations and fractional integro-differential equations. As its convenience, the computation of numerical solutions is time-saving and more accurate.
Details
Keywords
The purpose of this paper is to develop rationalized Haar functions to approximate the solutions of the integro‐differential equations.
Abstract
Purpose
The purpose of this paper is to develop rationalized Haar functions to approximate the solutions of the integro‐differential equations.
Design/methodology/approach
Properties of rationalized Haar functions are first presented, and the operational matrix of the product of two rationalized Haar functions vector is utilized to reduce the computation of integro‐differential equations to some algebraic equations.
Findings
Numerical results support the theoretical results.
Originality/value
Presents a method for solving integro‐differential equations.