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921.
M. Ferreira M. M. Rodrigues N. Vieira 《Mathematical Methods in the Applied Sciences》2017,40(18):7033-7050
In this work, we obtain the fundamental solution (FS) of the multidimensional time‐fractional telegraph Dirac operator where the 2 time‐fractional derivatives of orders α∈]0,1] and β∈]1,2] are in the Caputo sense. Explicit integral and series representation of the FS are obtained for any dimension. We present and discuss some plots of the FS for some particular values of the dimension and of the fractional parameters α and β. Finally, using the FS, we study some Poisson and Cauchy problems. 相似文献
922.
923.
924.
Helen?Parks Melvin?LeokEmail authorView authors OrcID profile 《Journal of Nonlinear Science》2017,27(5):1399-1434
Interconnected systems are an important class of mathematical models, as they allow for the construction of complex, hierarchical, multiphysics, and multiscale models by the interconnection of simpler subsystems. Lagrange–Dirac mechanical systems provide a broad category of mathematical models that are closed under interconnection, and in this paper, we develop a framework for the interconnection of discrete Lagrange–Dirac mechanical systems, with a view toward constructing geometric structure-preserving discretizations of interconnected systems. This work builds on previous work on the interconnection of continuous Lagrange–Dirac systems (Jacobs and Yoshimura in J Geom Mech 6(1):67–98, 2014) and discrete Dirac variational integrators (Leok and Ohsawa in Found Comput Math 11(5), 529–562, 2011). We test our results by simulating some of the continuous examples given in Jacobs and Yoshimura (2014). 相似文献
925.
Lovász theta function and the related theta body of graphs have been in the center of the intersection of four research areas: combinatorial optimization, graph theory, information theory, and semidefinite optimization. In this paper, utilizing a modern convex optimization viewpoint, we provide a set of minimal conditions (axioms) under which certain key, desired properties are generalized, including the main equivalent characterizations of the theta function, the theta body of graphs, and the corresponding antiblocking duality relations. Our framework describes several semidefinite and polyhedral relaxations of the stable set polytope of a graph as generalized theta bodies. As a by-product of our approach, we introduce the notion of “Schur Lifting” of cones which is dual to PSD Lifting (more commonly used in SDP relaxations of combinatorial optimization problems) in our axiomatic generalization. We also generalize the notion of complements of graphs to diagonally scaling-invariant polyhedral cones. Finally, we provide a weighted generalization of the copositive formulation of the fractional chromatic number by Dukanovic and Rendl from 2010. 相似文献
926.
Carlos Banquet Lucas C. F. Ferreira Élder J. Villamizar‐Roa 《Mathematical Methods in the Applied Sciences》2017,40(15):5613-5618
We consider a semilinear wave equation with nonlinear damping in the whole space . Local‐in‐time existence and uniqueness results are obtained in the class of Bessel‐potential spaces . Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
927.
Well‐posedness and regularity results for a 2m‐th order parabolic equation in symmetric conical domains of ℝN+1
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Saïda Cherfaoui Amor Kessab Arezki Kheloufi 《Mathematical Methods in the Applied Sciences》2017,40(16):6035-6047
In this paper, we use the domain decomposition method to prove well‐posedness and smoothness results in anisotropic weighted Sobolev spaces for a multidimensional high‐order parabolic equation set in conical time‐dependent domains of . Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
928.
929.
Paulo B. Gonçalves Frederico M. A. Silva Zenón J. G. N. Del Prado 《Nonlinear dynamics》2007,50(1-2):121-145
In the present study, the large-amplitude vibrations and stability of a perfect circular cylindrical shell subjected to axial
harmonic excitation in the neighborhood of the lowest natural frequencies are investigated. Donnell's shallow shell theory
is used and the shell spatial discretization is obtained by the Ritz method. An efficient low-dimensional model presented
in previous publications is used to discretize the continuous system. The main purpose of this work is to discuss the use
of basins of attraction as a measure of the reliability and safety of the structure. First, the nonlinear behavior of the
conservative system is discussed and the basin structure and volume is understood from the topologic structure of the total
energy and its evolution as a function of the system parameters. Then, the behavior of the forced oscillations of the harmonically
excited shell is analyzed. First the stability boundaries in force control space are obtained and the bifurcation events connected
with these boundaries are identified. Based on the bifurcation diagrams, the probability of parametric instability and escape
are analyzed through the evolution and erosion of basin boundaries within a prescribed control volume defined by the manifolds.
Usually, basin boundaries become fractal. This together with the presence of catastrophic subcritical bifurcations makes the
shell very sensitive to initial conditions, uncertainties in system parameters, and initial imperfections. Results show that
the analysis of the evolution of safe basins and the derivation of appropriate measures of their robustness is an essential
step in the derivation of safe design procedures for multiwell systems. 相似文献
930.
Near-wall data for the strongly perturbed flow in a neutrally stable boundary layer encountering a steep, smooth, two-dimensional
hill are presented. Observations were made on the centerplane of a water channel at thirteen stations relative to the hill
by laser Doppler anemometry. The large reverse flow region that is formed on the lee of the hill was particularly scrutinized
through seven measuring stations. Results are presented for the mean and turbulent properties of the flow. Wall shear stress
was evaluated through fitting procedures that resorted to the near wall behavior of the velocity profile. Logarithmic fits
as well as predictions through the Reynolds stress profiles are also presented. 相似文献