the current paper focuses on some analytical techniques to solve the non-linear duffing oscillator with large nonlinearity. four different methods have been applied for solution of the equation of motion; the variational iteration method, he’s parameter expanding method, parameterized perturbation method, and the homotopy perturbation method. the results reveal that approximation obtained by th...

the aim of present paper is to provide mathematical modelling for the two-dimensional mhd flow with induced magnetic field. the flaws in the already existing equations have been pointed out. the results of low magnetic reynolds number approximation are recovered as a special case from the developed equations. as an example, the peristaltic flow for a couple stress fluid in a channel is consider...

Robust optimization can provide safe and tractable analytical approximation for the chance constrained optimization problem. In this work, we studied the application of robust optimization approximation in solving chance constrained planning and scheduling problem under uncertainty. Four different robust optimization approximation methods for improving the quality of robust solution were invest...

This paper studies the discrete-time sampled-data approximation of the input-constrained finite-horizon linear quadratic regulator problem. Explicit estimates for the error in the performance index rendered by the solution of a discrete-time approximation are provided. This result can be used to evaluate the level of sub-optimality of the sampled-data solution corresponding to a given discretis...

We study the proximal gradient descent (PGD) method for l sparse approximation problem as well as its accelerated optimization with randomized algorithms in this paper. We first offer theoretical analysis of PGD showing the bounded gap between the sub-optimal solution by PGD and the globally optimal solution for the l sparse approximation problem under conditions weaker than Restricted Isometry...

in this paper, we introduce an efficient method for solving the quadratic riccati differential equation. in this technique, combination of laplace transform and new homotopy perturbation methods (ltnhpm) are considered as an algorithm to the exact solution of the nonlinear riccati equation. unlike the previous approach for this problem, so-called nhpm, the present method, does not need the init...

the dependence on ionic strength of protonation of l-aspartic acid and its complexation withdioxouranium(vi) is reported in sodium perchlorate solution as a background salt. the measurementshave been performed at 25 ± 0.1 °c and various ionic strengths in the range 0.1 to 1.0 mol dm-3, using acombination of potentiometric and spectrophotometric techniques. the overall analysis of the present an...

Vibration based techniques of structural damage detection using model updating method, are computationally expensive for large-scale structures. In this study, after locating precisely the eventual damage of a structure using modal strain energy based index (MSEBI), To efficiently reduce the computational cost of model updating during the optimization process of damage severity detection, the M...

In a combinatorial optimization problem, when given an input instance, one seeks a feasible solution that optimizes the value of the objective function. Many combinatorial optimization problems are NP-hard. A way of coping with NP-hardness is by considering approximation algorithms. These algorithms run in polynomial time, and their performance is measured by their approximation ratio: the wors...

Linear programming relaxations have been used extensively in designing approximation algorithms for optimization problems. For vertex cover, linear programming and a thresholding technique gives a 2-approximate solution, rivaling the best known performance ratio. For a generalization of vertex cover we call vc t , in which we seek to cover t edges, this technique may not yield a feasible soluti...