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901.
A class of finite-difference interface schemes suitable for two-dimensional cell-centered grids with patch-refinement and step-changes in resolution is presented. Grids of this type are generated by adaptive mesh refinement methods according to resolution needs dictated by the physics of the problem being modeled. For these grids, coarse and fine nodes are not aligned at the mesh interfaces, resulting in hanging nodes. Three distinct geometries are identified at the interfaces of a domain with interior patch-refinement: edges, concave corners and convex corners. Asymptotic stability in time of the numerical scheme is achieved by imposing a summation-by-parts condition on the interface closure, which is thus also nondissipative. Interface stencils corresponding to an explicit fourth-order finite-difference scheme are presented for each geometry. To preserve stability, a reduction in local accuracy is required at the corner geometries. It is also found that no second-order accurate solution exists that satisfies the summation-by-parts condition. Tests using the 2-D scalar advection equation and an inviscid compressible vortex support the stability and accuracy of these stencils for both linear and nonlinear problems. 相似文献
902.
Romano Scozzafava 《International Journal of Mathematical Education in Science & Technology》2013,44(5):685-688
The widespread use of computers for handling specific statistical techniques affects the teaching of probability and statistics, reducing the need for a utilitarian point of view. It is argued that this teaching may be enriched by emphasizing critical and fundamental aspects, in particular the applications of the Bayesian standpoint. 相似文献
903.
《随机分析与应用》2013,31(3):627-645
Abstract The notions of fuzzy random variables and fuzzy (super) submartingales are introduced. In this paper we provide the necessary and sufficient conditions of Doob's decomposition for fuzzy (super) submartingales. Finally, we discuss the decomposition of fuzzy (super) submartingales on R, and an example is given which explains that not every fuzzy (super) submartingale has Doob's decomposition. 相似文献
904.
Yu. A. Chernyaev 《Computational Mathematics and Mathematical Physics》2008,48(10):1768-1776
The conditional gradient method and the steepest descent method, which are conventionally used for solving convex programming problems, are extended to the case where the feasible set is the set-theoretic difference between a convex set and the union of several convex sets. Iterative algorithms are proposed, and their convergence is examined. 相似文献
905.
We prove that if E is a rearrangement-invariant space, then a boundedly complete basis exists in E, if and only if one of the following conditions holds: 1) E is maximal and E ≠ L 1[0, 1]; 2) a certain (any) orthonormal system of functions from L ∞[0, 1], possessing the properties of the Schauder basis for the space of continuous on [0, 1] functions with the norm L ∞, represents a boundedly complete basis in E. As a corollary, we state the following assertion: Any (certain) orthonormal system of functions from L ∞[0, 1], possessing the properties of the Schauder basis for the space of continuous on [0, 1] functions with the norm L ∞, represents a spanning basis in a separable rearrangement-invariant space E, if and only if the adjoint space E* is separable. We prove that in any separable rearrangement-invariant space E the Haar system either forms an unconditional basis, or a strongly conditional one. The Haar system represents a strongly conditional basis in a separable rearrangement-invariant space, if and only if at least one of the Boyd indices of this space is trivial. 相似文献
906.
The coflow min–max equality is given a travelling preacher interpretation, and is applied to give a lower bound on the maximum size of a set of vertices, no two of which are joined by an edge. 相似文献
907.
This paper studies variable separation of the evolution equations via the generalized conditional symmetry. To illustrate, we classify the extended nonlinear wave equation utt=Au,uxuxx+Bu,ux,ut which admits the derivative-dependent functional separable solutions DDFSSs). We also extend the concept of the DDFSS to cover other variable separation approaches. 相似文献
908.
A. J. Short 《Foundations of Physics Letters》2001,14(3):275-284
Application of the uncertainty principle to conditional measurements is investigated and found to be valid for measurements on separated sub-systems. In light of this, an apparent violation of the uncertainty principle obtained by Kim and Shih in their realization of Popper's experiment [1] is explained through analogy with a simple optical system. 相似文献
909.
本文给出有限群的分裂的Abel扩张的稳定自同构群的计算.作为应用,给出了循环群的半直积的自同构群的结构,它包括了若干已知结果,如文[1]的全部结果,并解决了[1]提出的问题. 相似文献
910.