in this paper, a new analytical approach has been presented for solving strongly nonlinear oscillator problems. iteration perturbation method leads us to high accurate solution. two different high nonlinear examples are also presented to show the application and accuracy of the presented method. the results are compared with analytical methods and with the numerical solution using runge-kutta m...

the purpose of this study is to implement a new modification of the variational iteration method (h-s-vim), which is a combination of spectral method and variational iteration method for heat transfer problems with high nonlinearity order. the merit of this method is that it does not require the solution of any linear or nonlinear system of equations unlike spectral method. furthermore the prop...

sinc-galerkin method based upon double exponential transformation for solving troesch's problem was given in this study. properties of the sinc-galerkin approach were utilized to reduce the solution of nonlinear two-point boundary value problem to same nonlinear algebraic equations, also, the matrix form of the nonlinear algebraic equations was obtained.the error bound of the method was fo...

alternative legendre polynomials (alps) are used to approximate the solution of a class of nonlinear volterra-hammerstein integral equations. for this purpose, the operational matrices of integration and the product for alps are derived. then, using the collocation method, the considered problem is reduced into a set of nonlinear algebraic equations. the error analysis of the method is given an...

comparison of linear and nonlinear (bilinear) time series models in reference crop evapotranspiration prediction in urmia synoptic stationreference crop evapotranspiration (eto) prediction is one of the important elements in optimizing agricultural water consumption. in this regard, one of the prediction approaches is to use the stochastic time series methods. in this research, ar (p) and arma(...

In this paper, by investigating the common weights concept and DEA models with nonlinear virtual inputs/outputs, we introduce a model for evaluating the decision making units with nonlinear virtual inputs and outputs based on the common weights.