نتایج جستجو برای: time domain method

تعداد نتایج: 3483685  

ژورنال: فیزیک زمین و فضا 2018

Time-frequency filtering is an acceptable technique for attenuating noise in 2-D (time-space) and 3-D (time-space-space) reflection seismic data. The common approach for this purpose is transforming each seismic signal from 1-D time domain to a 2-D time-frequency domain and then denoising the signal by a designed filter and finally transforming back the filtered signal to original time domain. ...

Journal: :فیزیک زمین و فضا 0
عبداله سهرابی بیدار استادیار، دانشکده زمین شناسی، دانشگاه تهران، ایران محسن کمالیان دانشیار، پژوهشکده مهندسی ژئوتکنیک، پژوهشگاه بین المللی زلزله شناسی و مهندسی زلزله، تهران، ایران محمد کاظم جعفری استاد، پژوهشکده مهندسی ژئوتکنیک، پژوهشگاه بین المللی زلزله شناسی و مهندسی زلزله، تهران، ایران

it is well established that the seismic ground response of surface topographies may differ from those of free field motion during earthquakes. complex nature of seismic wave scattering by topographical structures can only be solved accurately and economically using advanced numerical methods under realistic conditions. among the numerical methods, the boundary element is a powerful numerical te...

Journal: :international journal of electrical and electronics engineering 0
ehsan karami amirkabir shahram montaser kouhsari amirkabir seyed mahdi mazhari amirkabir

harmonics have become an important issue in modern power systems. the widespread penetration of non-linear loads to emerging power systems has turned power quality analysis into an important operation issue under both steady state and transient conditions. this paper employs an extended harmonic domain (ehd) based framework for dynamic analysis of long term analysis over voltages during the tra...

Journal: :IEEE Transactions on Antennas and Propagation 2022

A novel approach to computing time-harmonic solutions of Maxwell's equations by time-domain simulations is presented. The method, EM-WaveHoltz, results in a positive definite system which makes it amenable iterative solution with the conjugate gradient method or GMRES. Theoretical guaranteeing convergence away from resonances Numerical examples illustrating properties EM-WaveHoltz are given.

B. Vahidi M. Torabian Esfahani

An electric arc furnace (EAF) is known as nonlinear and time variant load that causes power quality (PQ) problems such as, current, voltage and current harmonics, voltage flicker, frequency changes in power system. One of the most important problems to study the EAF behavior is the choice of a suitable model for this load. Hence, in this paper, a probabilistic three-phase model is proposed base...

ژورنال: کنترل 2019

This paper presents a new approach to estimate and to enlarge the domain of attraction for a planar continuous-time piecewise affine system. Various continuous Lyapunov functions have been proposed to estimate and to enlarge the system’s domain of attraction. In the proposed method with a new vision and with the aids of a discontinuous piecewise quadratic Lyapunov function, the domain of attrac...

Journal: :فیزیک زمین و فضا 0
هانیه جهدی حمیدرضا سیاهکوهی

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Journal: :بینا 0
ابراهیم جعفرزاده پور e jafarzadehpour تهران- میرداماد- میدان محسنی- خیابان شهید شاه نظری- دانشکده علوم توانبخشی- گروه بینایی سنجی

purpose: comparison of the results of visual evoked potential (vep) in time domain and frequency domain between multiple sclerosis (ms) suspected patients and normal indivisuals. method: eleven ms suspected patients with normal visual findings and 20 normal individuals were tested by vep. results were compared between two groups. results: the time domain results showed no significant difference...

Journal: :international journal of civil engineering 0
jafar najafizadeh no. 21, arghavan st., north dibajee, farmanieh, tehran, islamic republic of iran mohsen kamalian no. 21, arghavan st., north dibajee, farmanieh, tehran, islamic republic of iran mohammad kazem jafari no. 21, arghavan st., north dibajee, farmanieh, tehran, islamic republic of iran naser khaji faculty of civil and environmental engineering, tarbiat modares university

in this paper, an advanced formulation of the spectral finite element method (sfem) is presented and applied in order to carry out site response analysis of 2d topographic structures subjected to vertically propagating incident in-plane waves in time-domain. the accuracy, efficiency and applicability of the formulation are demonstrated by solving some wave scattering examples. a numerical param...

The transient flow analyzing by the frequency domain method (FDM) is computationally much faster than the method of characteristic (MOC) in the time domain. FDM needs no discretization in time and space, but requires the linearization of governing equations and boundary conditions. Hence, the FDM is only valid for small perturbations in which the system’s hydraulics is almost linear. In this st...

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