12,550 research outputs found
An advanced meshless method for time fractional diffusion equation
Recently, because of the new developments in sustainable engineering and renewable energy, which are usually governed by a series of fractional partial differential equations (FPDEs), the numerical modelling and simulation for fractional calculus are attracting more and more attention from researchers. The current dominant numerical method for modeling FPDE is Finite Difference Method (FDM), which is based on a pre-defined grid leading to inherited issues or shortcomings including difficulty in simulation of problems with the complex problem domain and in using irregularly distributed nodes. Because of its distinguished advantages, the meshless method has good potential in simulation of FPDEs. This paper aims to develop an implicit meshless collocation technique for FPDE. The discrete system of FPDEs is obtained by using the meshless shape functions and the meshless collocation formulation. The stability and convergence of this meshless approach are investigated theoretically and numerically. The numerical examples with regular and irregular nodal distributions are used to validate and investigate accuracy and efficiency of the newly developed meshless formulation. It is concluded that the present meshless formulation is very effective for the modeling and simulation of fractional partial differential equations
Guiding the selection of service-oriented software engineering methodologies
Service-oriented computing is a paradigm for effectively delivering software services in a dynamic environment. Accordingly, many service-oriented software engineering (SOSE) methodologies have been proposed and practiced in both academia and industry. Some of these methodologies share common features (e. g. cover similar life-cycle phases) but are presented for different purposes, ranging from project management to system modernization, and from business analysis to technical solutions development. Given this diversity in the methodologies available in the literature, it is very hard for a company to decide which methodology would fit best for its specific needs. With this aim, we took a feature analysis approach and devised a framework for comparing the existing SOA methodologies. Different from existing comparison frameworks, ours specifically highlights aspects that are specific to SOA and aims to differentiate the methodologies that are truly service-oriented from those that deal little with service aspects. As such, the criteria defined in the framework can be used as a checklist for selecting a SOSE methodology. © 2011 The Author(s)
Effective generation of Ising interaction and cluster states in coupled microcavities
We propose a scheme for realizing the Ising spin-spin interaction and atomic
cluster states utilizing trapped atoms in coupled microcavities. It is shown
that the atoms can interact with each other via the exchange of virtual photons
of the cavities. Through suitably tuning the parameters, an effective Ising
spin-spin interaction can be generated in this optical system, which is used to
produce the cluster states. This scheme does not need the preparation of
initial states of atoms and cavity modes, and is insensitive to cavity decay.Comment: 11pages, 2 figures, Revtex
Multipole polarizability of a graded spherical particle
We have studied the multipole polarizability of a graded spherical particle
in a nonuniform electric field, in which the conductivity can vary radially
inside the particle. The main objective of this work is to access the effects
of multipole interactions at small interparticle separations, which can be
important in non-dilute suspensions of functionally graded materials. The
nonuniform electric field arises either from that applied on the particle or
from the local field of all other particles. We developed a differential
effective multipole moment approximation (DEMMA) to compute the multipole
moment of a graded spherical particle in a nonuniform external field. Moreover,
we compare the DEMMA results with the exact results of the power-law graded
profile and the agreement is excellent. The extension to anisotropic DEMMA will
be studied in an Appendix.Comment: LaTeX format, 2 eps figures, submitted for publication
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Nonlinear alternating current responses of graded materials
When a composite of nonlinear particles suspended in a host medium is
subjected to a sinusoidal electric field, the electrical response in the
composite will generally consist of alternating current (AC) fields at
frequencies of higher-order harmonics. The situation becomes more interesting
when the suspended particles are graded, with a spatial variation in the
dielectric properties. The local electric field inside the graded particles can
be calculated by the differential effective dipole approximation, which agrees
very well with a first-principles approach. In this work, a nonlinear
differential effective dipole approximation and a perturbation expansion method
have been employed to investigate the effect of gradation on the nonlinear AC
responses of these composites. The results showed that the fundamental and
third-harmonic AC responses are sensitive to the dielectric-constant and/or
nonlinear-susceptibility gradation profiles within the particles. Thus, by
measuring the AC responses of the graded composites, it is possible to perform
a real-time monitoring of the fabrication process of the gradation profiles
within the graded particles.Comment: 18 pages, 4 figure
Ground-state fidelity of Luttinger liquids: A wave functional approach
We use a wave functional approach to calculate the fidelity of ground states
in the Luttinger liquid universality class of one-dimensional gapless quantum
many-body systems. The ground-state wave functionals are discussed using both
the Schrodinger (functional differential equation) formulation and a path
integral formulation. The fidelity between Luttinger liquids with Luttinger
parameters K and K' is found to decay exponentially with system size, and to
obey the symmetry F(K,K')=F(1/K,1/K') as a consequence of a duality in the
bosonization description of Luttinger liquids.Comment: 13 pages, IOP single-column format. Sec. 3 expanded with discussion
of short-distance cut-off. Some typos corrected. Ref. 44 in v2 is now
footnote 2 (moved by copy editor). Published versio
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