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In power distribution systems, sometimes, system reliability indices are available, where some components' reliability parameters are unknown. This letter presents the inverse reliability evaluation (IRE) problem in radial distribution systems to find unknown components' parameters from the known system reliability indices. To this end, a nonlinear system of equations is presented and solved. The solutions are analyzed in the RBTS bus 2 to verify the applicability of the proposed approach and to show the importance of the IRE problem. © 1969-2012 IEEE  

In this paper, we propose a new derivative-free preconditioned conjugate gradient method in order for solving large-scale square and under-determined nonlinear systems of equations. The proposed method is also equipped with a relaxed nonmonotone line search technique. Under some suitable assumptions, the global convergence property is established. Numerical results on some square and under-determined test systems show the efficiency and effectiveness of the new method in practice. An application of the new method for solving nonlinear integro-differential equations is also provided. © 2016 Elsevier Ltd  

In this manuscript, an advanced damage-plasticity model is utilized to simulate response of concrete structures under high-velocity impact. Due to presence of large deformations, it is necessary to incorporate the damage-plasticity model into the finite deformation framework. In high-velocity impact, severe numerical problems could be encountered while updating stress values due to the sudden increase in their levels, especially for the complicated material model used in this study. To overcome these obstacles, an enhancement is made in the nonlinear system of equations of stress- updating procedure. In addition, an adaptive multi-step numerical algorithm is introduced which improves the... 

In this paper, the aeroelastic analysis of a large scale wind turbine rotor is performed with the aim of studying transient performance of turbine in extreme wind conditions, such as wind gusts and rapid yaw changes. The effect of the presence and/or lack of blade pitch control system on output power, rotor thrust, and blade deformation in sudden change of wind speed are investigated. The NREL 5 MW offshore wind turbine is used as the baseline case. In this regard, the modal approach is implemented for modeling the flexible blade structure with tension, bending and torsion degrees of freedom. The unsteady vortex lattice method is employed to obtain the aerodynamic loads. Moreover, the...