نتایج جستجو برای: perturbation techniques

تعداد نتایج: 685705  

2013
Michael Creutz

Lattice gauge theory and chiral perturbation theory are among the primary tools for understanding non-perturbative aspects of QCD. I review several subtle and sometimes controversial issues that arise when combining these techniques. Among these are one failure of partially quenched chiral perturbation theory when the valence quarks become lighter than the average sea quark mass and a potential...

2004
T. S. NAVEENDRA

This work is motivated by the fact that basestation receiver performance degrades significantly in spatially diffused multipath channels. Herein, this problem is addressed for array DS-CDMA systems in spatially diffused vector channels. Firstly, multipath spatial diffusion is cast as a signal model perturbation problem and then two subspace based receiver techniques are proposed that effectivel...

Journal: :Optics letters 2005
Yang Jiao Shanhui Fan David A B Miller

We present a powerful sensitivity analysis method for devices in a photonic crystal. The method is based on a Wannier basis field expansion and efficient matrix analysis techniques for finding eigenvalue and transmission gradients with respect to the perturbation. The method permits fast analysis of a large number of dielectric perturbation situations for multiple devices in a photonic crystal....

پایان نامه :0 1375

this study examines the effetivenss of task-based activities in helping students learn english language structures for a better communication. initially, a michigan test was administered to the two groups of 52 students majoring in english at the allameh ghotb -e- ravandi university to ensure their homogeneity. the students scores on the grammar part of this test were also regarded as their pre...

M Aghaie-Khafri, M.H Sheikh-Ansari

Semi-solid materials undergo strain localization and shear band formation as a result of granular nature of semi-solid deformation. In the present study, to analyze the shear localization, a unified viscoplastic constitutive model was developed for the homogeneous flow. Then, a linearized analysis of the stability performed by examining the necessary condition for the perturbation growth. For t...

2016
Robert G. Littlejohn

Bound state perturbation theory applies to the bound states of perturbed systems, for which the energy levels are discrete and separated from one another. The system may also have a continuous spectrum, but the interest is attached to the discrete states. The effects of perturbations on states of the continuous spectrum, or on discrete states imbedded in the continuum, require different techniq...

2013
Wen Li Lin Jiang Wai-Ki Ching Lu-Bin Cui L. Cui

Multivariate Markov chain models have previously been proposed in for studying dependent multiple categorical data sequences. For a given multivariate Markov chain model, an important problem is to study its joint stationary distribution. In this paper, we use two techniques to present some perturbation bounds for the joint stationary distribution vector of a multivariate Markov chain with s ca...

Journal: :Adv. Comput. Math. 2010
Pedro G. Massey Mariano A. Ruiz

We present results about minimization of convex functionals defined over a finite set of vectors in a finite dimensional Hilbert space, that extend several known results for the Benedetto-Fickus frame potential. Our approach depends on majorization techniques. We also consider some perturbation problems, where a positive perturbation of the frame operator of a set of vectors is realized as the ...

2001
S Kais

The bound state solutions of Schrodinger’s equation for the anharmonic oscillator potentials V = x2+ AxZk ( k = 2 , 3 , . . .) have been investigated, using elementary techniques of low-order variational perturbation theory. For the quartic oscillator ( k = 2) a scaled harmonic potential provides a remarkably accurate model for all A. Although this model is slightly less satisfactory for higher...

M. Ghasemi M. Matinfar

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...

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