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111.
112.
O. S. Klass O. Biham M. Levy O. Malcai S. Solomon 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,55(2):143-147
Statistical regularities at
the top end of the wealth distribution in the United States are
examined using the Forbes 400 lists of richest Americans,
published between 1988 and 2003.
It is found that the wealths are distributed according to a power-law
(Pareto) distribution.
This result is explained using a
simple stochastic model
of multiple investors that incorporates the
efficient market hypothesis
as well as the multiplicative nature of financial market fluctuations. 相似文献
113.
Wen-Rong Dai 《Journal of Mathematical Analysis and Applications》2007,327(1):188-202
In this paper, we study the regularity of the eigenvalues and eigenvectors and the existence of normalized coordinates for quasilinear hyperbolic systems with characteristic fields of constant multiplicity. We prove that the eigenvalues and eigenvectors of the system have the same regularity as the coefficients of the system. On the other hand, we show that, for the quasilinear hyperbolic system of conservation laws with characteristic fields of constant multiplicity, the normalized coordinates exist on the domain under consideration. 相似文献
114.
Space-Time Point-Process Models for Earthquake Occurrences 总被引:5,自引:0,他引:5
Yosihiko Ogata 《Annals of the Institute of Statistical Mathematics》1998,50(2):379-402
Several space-time statistical models are constructed based on both classical empirical studies of clustering and some more speculative hypotheses. Then we discuss the discrimination between models incorporating contrasting assumptions concerning the form of the space-time clusters. We also examine further practical extensions of the model to situations where the background seismicity is spatially non-homogeneous, and the clusters are non-isotropic. The goodness-of-fit of the models, as measured by AIC values, is discussed for two high quality data sets, in different tectonic regions. AIC also allows the details of the clustering structure in space to be clarified. A simulation algorithm for the models is provided, and used to confirm the numerical accuracy of the likelihood calculations. The simulated data sets show the similar spatial distributions to the real ones, but differ from them in some features of space-time clustering. These differences may provide useful indicators of directions for further study. 相似文献
115.
In this paper we consider scalar convex conservation laws in one space variable in a stripD =(x, t): 0 ≤x ≤1,t > 0 and obtain an explicit formula for the solution of the mixed initial boundary value problem, the boundary data being
prescribed in the sense of Bardos-Leroux and Nedelec. We also get an explicit formula for the solution of weighted Burgers
equation in a strip. 相似文献
116.
Mustansir Barma 《Pramana》1997,49(1):155-160
When the dynamics of a system partitions the phase space of configurations into very many disjoint sectors, we are faced with an assignment problem: Given a configuration, how can we tell which sector it belongs to? We study this problem in connection with the dynamics of deposition and evaporation ofk particles at a time, from a lattice substrate. Fork ≥ 3, the system shows complex behaviour: (a) The number of disjoint sectors in phase space grows exponentially with the size. (b) The asymptotic time dependence of the autocorrelation function shows slow decays, with power laws which depend on the sector. Both (a) and (b) are explained in terms of a nonlocal construct known as the irreducible string (IS), formed from a particle configuration by applying a deletion algorithm. The IS provides a label for sectors; the multiplicity of possible IS’s accounts for (a), and let us determine sector numbers and sizes. The elements of the IS are conserved; thus their motion is responsible for the slow modes of the system, and accounts for (b) as well. 相似文献
117.
118.
We study a few problems related to Markov processes of flipping triangulations of the sphere. We show that these processes
are ergodic and mixing, but find a natural example which does not satisfy detailed balance. In this example, the expected
distribution of the degrees of the nodes seems to follow the power law d
−4. 相似文献
119.
Scott A. Sarra 《Numerical Algorithms》2006,41(1):17-33
Digital total variation filtering is analyzed as a fast, robust, post-processing method for accelerating the convergence of
pseudospectral approximations that have been contaminated by Gibbs oscillations. The method, which originated in image processing,
can be combined with spectral filters to quickly post-process large data sets with sharp resolution of discontinuities and
with exponential accuracy away from the discontinuities. 相似文献
120.