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181.
Summary A tool for analyzing spatio-temporal complex physical phenomena was recently proposed by the authors, Aubry et al. [5]. This
tool consists in decomposing a spatially and temporally evolving signal into orthogonal temporal modes (temporal “structures”)
and orthogonal spatial modes (spatial “structures”) which are coupled. This allows the introduction of a temporal configuration
space and a spatial one which are related to each other by an isomorphism. In this paper, we show how such a tool can be used
to analyze space-time bifurcations, that is, qualitative changes in both space and time as a parameter varies. The Hopf bifurcation
and various spatio-temporal symmetry related bifurcations, such as bifurcations to traveling waves, are studied in detail.
In particular, it is shown that symmetry-breaking bifurcations can be detected by analyzing the temporal and spatial eigenspaces
of the decomposition which then lose their degeneracy, namely their invariance under the symmetry. Furthermore, we show how
an extension of the theory to “quasi-symmetries” permits the treatment of nondegenerate signals and leads to an exponentially
decreasing law of the energy spectrum. Examples extracted from numerically obtained solutions of the Kuramoto-Sivashinsky
equation, a coupled map lattice, and fully developed turbulence are given to illustrate the theory. 相似文献
182.
183.
F. Bontempi 《Nonlinear dynamics》1995,7(2):217-229
This paper deals with the dynamics of a truss structure, the Euler arch. The bars are made of elastic-plastic material, and the structure can exhibit large displacements. The aim of this paper is to give evidence of the possible chaotic behavior of this structure, even in the presence of a hardening plastic branch. The tools used are the diagrams of bifurcation, the measure of the dimension of the attractor, the Kolmogorov entropy, and the maximum Lyapunov exponent. This study emphasizes the sensitivity to the initial conditions by means of generalized basins of attraction. 相似文献
184.
Jörn Loviscach 《Journal of statistical physics》1994,75(1-2):189-213
Strongly chaotic systems (e.g., piecewise expanding mappings) exhibit diffusion-like behavior in the sense of central limit theorems. To find more precise statements about the similarity to probabilistic diffusion, we study how the evolution of probability densities underd-dimensional piecewise expanding mappings can be modeled by Markov processes with smooth transition probabilities (such as diffusion processes). Our results can be viewed as a special type of local limit theorem. 相似文献
185.
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188.
非线性非均衡蛛网模型的动态分析 总被引:5,自引:0,他引:5
黄赜琳 《数学的实践与认识》2004,34(3):40-45
描述单商品市场价格波动的蛛网模型是动态经济分析中的经典模型 ,证明了由模型 ( )所生成的价格序列在一定的条件下不会出现 3以上周期运动和混沌现象 ,并对其进行稳定性分析 ,得到模型关于均衡价格稳定的六个判别定理 . 相似文献
189.
Local structure theory calculations7 are applied to the study of cellular automata on the two-dimensional hexagonal lattice. A particular hexagonal lattice rule denoted (3422) is considered in detail. This rule has many features in common with Conway'sLife. The local structure theory captures many of the statistical properties of this rule; this supports hypotheses raised by a study ofLife itself(6). As inLife, the state of a cell under (3422) depends only on the state of the cell itself and the sum of states in its neighborhood at the previous time step. This property implies that evolution rules which operate in the same way can be studied on different lattices. The differences between the behavior of these rules on different lattices are dramatic. The mean field theory cannot reflect these differences. However, a generalization of the mean field theory, the local structure theory, does account for the rule-lattice interaction. 相似文献
190.