排序方式: 共有9条查询结果,搜索用时 20 毫秒
1
1.
广义Taylor映射与Hénon映射具有混沌条件的改进 总被引:3,自引:0,他引:3
本文进一步讨论了近年来动力系统中关于对具有混沌现象的Taylor映射,Henon映射等函数所做的研究,并着重分析了所讨论函数的参数. 相似文献
2.
系统地分析了Lemple-Ziv复杂性度量方法的应用过程中,将实际信号(时间序列)转变成符号序列的诸多方法中存在的一些问题,提出了更合理兼容法.该方法可以有效地刻划各种时间序列的复杂度.文章最后动态地分析了中国证券市场的复杂性. 相似文献
3.
提出了复合符号混沌序列的概念;并以符号动力学的揉序列为基础,将已知的伪随机数与揉序列规则下的短序列复合后得到新的符号混沌序列,再转换成二进制序列,从而得到长度随迭代次数成几何级数增加的伪随机序列(PRN).理论与实证分析都表明这是一个有效的伪随机生成器.为应用到图像的加解密技术中,建立了一个新型元胞自动机.该元胞自动机能有效地避免数据膨胀,加密效率高,并能产生显著的"雪崩效应",提高了加密技术的安全性.
关键词:
复合符号混沌序列
符号动力学
伪随机序列
元胞自动机 相似文献
4.
A universal algorithm to generate pseudo-random numbers based on uniform mapping as homeomorphism
下载免费PDF全文
![点击此处可从《中国物理 B》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A specific uniform map is constructed as a homeomorphism mapping chaotic time series into [0,1] to obtain sequences of standard uniform distribution. With the uniform map, a chaotic orbit and a sequence orbit obtained are topologically equivalent to each other so the map can preserve the most dynamic properties of chaotic systems such as permutation entropy. Based on the uniform map, a universal algorithm to generate pseudo random numbers is proposed and the pseudo random series is tested to follow the standard 0-1 random distribution both theoretically and experimentally. The algorithm is not complex, which does not impose high requirement on computer hard ware and thus computation speed is fast. The method not only extends the parameter spaces but also avoids the drawback of small function space caused by constraints on chaotic maps used to generate pseudo random numbers. The algorithm can be applied to any chaotic system and can produce pseudo random sequence of high quality, thus can be a good universal pseudo random number generator. 相似文献
5.
Based on forbidden patterns in symbolic dynamics, symbolic
subsequences are classified and relations between forbidden patterns, correlation
dimensions and complexity measures are studied. A complexity measure
approach is proposed in order to separate deterministic (usually chaotic) series
from random ones and measure the complexities of different dynamic systems.
The complexity is related to the correlation dimensions, and the algorithm is simple and
suitable for time series with noise. In the paper, the complexity measure method is used
to study dynamic systems of the Logistic map and the H\'enon map with multi-parameters. 相似文献
6.
A new method is proposed to transform the time series gained from a
dynamic system to a symbolic series which extracts both overall
and local information of the time series. Based on the
transformation, two measures are defined to characterize the
complexity of the symbolic series. The measures reflect the
sensitive dependence of chaotic systems on initial conditions and
the randomness of a time series, and thus can distinguish periodic
or completely random series from chaotic time series even though the
lengths of the time series are not long. Finally, the logistic map
and the two-parameter Henón map are studied and the results are
satisfactory. 相似文献
7.
将高维混沌理论应用到中国证券市场的分析之中,指出了当前许多文献中计算中国证券市场混沌特征指数出现较大差异的原因.通过比较上证综合指数与英国M organ S tan ley C ap ita l In ternationa l指数后指出,中国证券市场较复杂,且存在较多的高维(接近四维)混沌成分. 相似文献
8.
王福来 《数学的实践与认识》2007,37(12):173-178
首先从符号动力学的角度论证了一簇Lorenz映射且有的混沌性质:稠密的周期轨道,周期的集合,拓扑熵,几乎所有(关于Lebesgue测度)的点的Lyapunov指数;并从揉序列的分析给出了该簇映射的拓扑熵的一个下界及Lyapunov指数的一个下界与上界,在很大程度上反应了Lorenz系统的复杂程度.其次仍从符号动力学的角度论证了更一般的Lorenz映射,通过设立参数空间,穷尽了Lorenz映射中函数为直线段的所有情况,并得出同前述Lorenz映射相似的且较为复杂的性质. 相似文献
9.
构造了一个具有较大密钥空间的新型一维元胞自动机. 在该元胞自动机中,密钥为采用移位映射的伪随机序列及受控扰动项,避免了数据膨胀,元胞自动机具有随机性触发规则. 该元胞自动机一次处理信息量大,避免了复杂的计算过程. 所生成的流密码在理论上被证明了具有理想的随机性与雪崩效应,误差扩散速度快. 实证分析研究表明,流密码不仅在全局上、而且在局部上都具有良好的随机性能,通过测试长度为24000的流密码在400次迭代产生的数据表明,经χ2检验,在显著性水平为5%时,频数检验通过率超
关键词:
保密通信
元胞自动机
伪随机序列 相似文献
1