In this paper, Numerical solution of Differential-Algebraic equations (DAEs) with index-3 is considered by Pade approximation. We applied this method to two examples. First differential-algebraic equations (DAEs) with index-3 has been converted to power series by one-dimensional differential transformation, Then the numerical solution of equation was put into Pade series form. Thus we obtained ...

A mixed method by combining a Eigen algorithm and improved pade approximations is proposed for reducing the order of the large-scale dynamic systems. The most dominant Eigen value of both original and reduced order systems remain same in this method. The proposed method guarantees stability of the reduced model if the original high-order system is stable and is comparable in quality with the ot...

In this paper, a new method is presented to derive a reduced order model for a discrete time systems. This method is based on modified pole clustering technique and pade approximations using bilinear transformations, which are conceptually simple and computer oriented. The denominator polynomial of the reduced order model is obtained by using modified pole clustering technique and numerator coe...

in this paper, nonlinear klein-gordon equation with quadratic term is solved by means of an analytic technique, namely the homotopy analysis method (ham).comparisons are made between the adomian decomposition method (adm), the exact solution and homotopy analysis method. the results reveal that the proposed method is very effective and simple.

The cluster-variation-Pade-approximant method is a recently proposed tool, based on the extrapolation of low- and high-temperature results obtained with the cluster-variation method, for the determination of critical parameters in Ising-like models. Here the method is applied to the three-dimensional simple cubic Ising model, and new results, obtained with an 18-site basic cluster, are reported...

in this paper, elzaki homotopy perturbation method is employed for solving linear and nonlinear differential equations with a variable coffecient. this method is a combination of elzaki transform and homotopy perturbation method. the aim of using elzaki transform is to overcome the deficiencies that mainly caused by unsatised conditions in some semi-analytical methods such as homotopy perturbat...

This paper proposed a new approach of controller design. By using model matching method we design a PID controller for higher order system. A higher order model is reduced by Pade approximation and mixed method, then design a controller for reduced order model. We take a comparatively study between close loop response of higher order system and reduced order system. The model order reduction an...

although homotopy-based methods, namely homotopy analysis method andhomotopy perturbation method, have largely been used to solve functionalequations, there are still serious questions on the convergence issue of thesemethods. some authors have tried to prove convergence of these methods, butthe researchers in this article indicate that some of those discussions are faulty.here, after criticizi...

in this study, a new efficient semi-analytical method is introduced to give approximate solutions of strongly nonlinear oscillators. the proposed method is based on combination of two different methods, the multi-step homotopy analysis method and spectral method, called the multi-step spectral homotopy analysis method (msham). in this method, firstly, we propose a new spectral homotopy analysis...