搜索结果: 16-30 共查到“知识库 离散数学”相关记录173条 . 查询时间(2.021 秒)
提出一种求解Riesz空间分布阶的分数阶扩散方程的数值方法。利用辛普森数值求积公式，将分布阶微分方程离散为一个多项分数阶导数的微分方程；利用四阶差分格式求解此具有多项分数阶导数的微分方程，并运用能量法分析数值格式的稳定性和收敛性。同时，给出数值例子，说明所建立的数值离散格式的有效性。
In the famous papers [1] and [2], J Cheeger, S Chern and J Simons define characteristic
classes for flat G–bundles. Each such characteristic class is given by a corresponding
universal c...
Discrete Gradient Flows for Shape Optimization and Applications
Shape optimization scalar product gradient flow
2015/12/11
We present a variational framework for shape optimization problems
that establishes clear and explicit connections among the continuous formulation, its full discretization and the resulting linear a...
Homogenization of reconstructed crystal surfaces:Fick’s law of diffusion
Homogenization reconstructed crystal surfaces Fick’s law of diffusion
2015/10/16
Fick’s law for the diffusion of adsorbed atoms adatoms on crystal surfaces below roughening is generalized to account for surface reconstruction. In this case, material parameters vary spatially at ...
From crystal steps to continuum laws:Behavior near large facets in one dimension
Crystal surface Epitaxial relaxation Self-similar solution Burton–Cabrera–Frank (BCF) model Facet Macroscopic limit
2015/10/16
The passage from discrete schemes for surface line defects (steps) to nonlinear macroscopic laws for crystals is studied via formal asymptotics in one space dimension. Our goal is to illustrate by exp...
分数阶偏微分电报方程一种解法的数值验证
分数阶电报方程 数值解 差分格式 精度
2016/7/25
对于二维分数阶偏微分波动方程，前人通过差分格式离散的方法求出了数值解；为了进一步提高数值解的精度，减小误差，采用了另一种差分格式；传统的离散方式在所选择的离散点处直接按分数阶导数的定义离散，现在采取的方法是在所给相邻两个离散点连线的中点进行离散；为了证明此种差分格式是否有效，选取了一个数值算例进行编程计算。最终证明中点离散算法的数值解具有较高精度。
CONVERGENCE OF MOMENTS FOR DISPERSING BILLIARDS WITH CUSPS
Chaos decay of correlations Central Limit Theorem
2015/9/29
Dispersing billiards with cusps are deterministic dnamical systems with a mild degree of chaos, exhibiting “intermittent” behavior that alternates between regular and chaotic paterns.
DIFFUSIVE MOTION AND RECURRENCE ON AN IDEALIZED GALTON BOARD
DIFFUSIVE MOTION AN IDEALIZED GALTON BOAR
2015/9/29
We study a mechanical model known as Galton board
{ a particle rolling on a tilted plane under gravitation and bouncing o a periodic array of rigid obstacles (pegs). This model is also
identical to...
A classical model of Brownian motion consists of a heavy molecule
submerged into a gas of light atoms in a closed container. In this work
we study a 2D version of this model, where the molecule is a...
This paper presents a framework for discretetime signal reconstruction from absolute values of its shorttime Fourier coefficients. Our approach has two steps. In step one we reconstruct a band-diagona...
Local rigidity of discrete groups acting on complex hyperbolic space
complex hyperbolic space Local rigidity
2015/9/29
The superrigidity theorem of Margulis, see Zimmer [17], classifies finite dimen-sional representations of lattices in semi-simple Lie groups of real rank strictly
larger than 1. It is a fundamental ...
CHARACTERISTIC CLASSES AND REPRESENTATIONS OF DISCRETE SUBGROUPS OF LIE GROUPS
CHARACTERISTIC CLASSES REPRESENTATIONS
2015/9/29
(For convenience we shall henceforth assume that n is torsionfree: by
Selberg's lemma [12] this may be accomplished by replacing TT by a subgroup of
finite index. This insures that M is a compact ...
Suppose G(R) is a real reductive group, with L-group ∨GΓ, and φ : WR →∨G Γ is an L-homomorphism.There is a close relationship between the Lpacket associated to φ and characters the component group of ...
Uncertainty Principles and Ideal Atomic Decomposition
Uncertainty Principles Ideal Atomic Decomposition
2015/8/21
Suppose a discrete-time signal S(t), 0 t
Continuous Curvelet Transform: II. Discretization and Frames
Curvelets Parabolic Scaling Fourier Integral Operator
2015/8/21
We develop a unifying perspective on several decompositions exhibiting directional parabolic
scaling. In each decomposition, the individual atoms are highly anisotropic at fine scales,
with e&...