激光对DNA分子的非线性作用效应的混沌行为分析

本文对第一作者提出的激光－ＤＮＡ相互作用方程的非线性混沌行为进行了解析分析和数值分析，将有助于对激光的生物遗传诱变效应的解释．     

强混沌噪声背景下弱信号自适应检测

本文提出了一种强混沌噪声中检测微弱正弦信号的自适应方法.该方法在硬件设计上容易实现,并且计算量小,算法复杂度为a(n).计算机仿真实验结果表明:该方法能够比较精确地检测到强混沌噪声中的微弱信号,检测的信噪比可达到:-40dB.     

Chaos theory,informational needs,and natural disasters

This study applies chaos theory to a system-wide analysis of crisis communication in a natural disaster. Specifically, we analyze crisis communication during the 1997 Red River Valley flood in Minnesota and North Dakota. This flood, among the worst in modern American history, consumed entire metropolitan areas, displacing thousands of people. The conditions and decisions leading to the disaster, and the subsequent reactions are retraced. Communication related to river crest predictions (fractals), the shock at the magnitude of the crisis (cosmology episode), novel forms of reorganizing (self-organization), and agencies that aided in establishing a renewed order (strange attractors) are evaluated. Ultimately, we argue that preexisting sensemaking structures favoring rationalized, traditional views of a complex system led officials to make inappropriately unequivocal predictions and ultimately diminished the effectiveness of the region's crisis communication and planning.     

Power laws and athletic performance

In a previous study,we showed that the 1992 men's world record running times in the 100 m to 200 km could be represented accurately by the equation T= cDn, where T is the calculated record time for distance D, and c and n are positive constants. Here, we extend that to cover the years 1925-65 at 10-year intervals and 1970-95 in 5-year intervals for distances of 100 m to 10 km. Values of n for all years lie along a straight line with a small negative slope. A regression analysis yields an equation for values of n covering the period 1925-95. Values of c from 1925 to 1995 were fitted by a quadratic equation. These two equations define a surface in three-dimensional space log(T), log(D), date for all men's world record runs over the 70-year period for distances of 100 m to 10 km. We also demonstrated previously that event times, t, do not scatter randomly with respect to the values of T but form a consistent pattern about the straight lines in log(T) versus log(D) plots. In this study, we show that the pattern of (t-T)/t as a function of date has remained constant for the past 70 years.     

Bifurcation and chaos of a 4-side fixed rectangular thin plate in electromagnetic and mechanical fields

We studied the problem of bifurcation and chaos in a 4-side fixed rectangular thin plate in electromagnetic and mechanical fields. Based on the basic nonlinear electro-magneto-elastic motion equations for a rectangular thin plate and the expressions of electromagnetic forces, the vibration equations are derived for the mechanical loading in a steady transverse magnetic field. Using the Melnikov function method, the criteria are obtained for chaos motion to exist as demonstrated by the Smale horseshoe mapping. The vibration equations are solved numerically by a fourth-order Runge-Kutta method. Its bifurcation diagram, Lyapunov exponent diagram, displacement wave diagram, phase diagram and Poincare section diagram are obtained.     

Lorenz-like系统的线性反馈控制

在考虑lorenz-like混沌系统的定性行为基础之上,利用单参数线性反馈控制方法控制该系统,并借助Routh-Hurwitz准则对受控系统进行了定性分析,给出了控制参数的选择原则.经大量的的数值模拟,证实了该控制方法的有效性.     

浅谈赫鲁晓夫执政初期的“拨乱反正”

赫鲁晓夫上台针对斯大林时期的“个人崇拜”及其它种种错误,采取了拨乱反正的一系列措施：公开批判斯大林的“个人崇斧”,解放人们的思想;平反冤假错案,恢复正常的社会政治关系;在思想文化层进行“解冻”．赫鲁晓夫通过这一系列措施,扭转了社会生活的极不正常状态,促进了经济文化等各项社会事业的恢复和发展,也为其改革的推行奠定了坚实的基础．     

杜芬振子的仿真分析

混沌系统对微弱信号具有极强的敏感性,同时对噪声具有极大的抑制能力,它的这种性质使得混沌系统具有可应用于小信号检测中的潜力。一个动态非线性系统有四种状态即定态、动态、周期振荡和混沌运动状态,当系统处在一个临界状态,系统参数的一个微小变化也可能引起系统状态的性质变化,即方程的解在相空间的轨迹将发生变化。以杜芬方程作为研究系统,利用MATLAB软件对方程分析、模拟。在临界状态下,系统加入与外力频率相近的单频被测信号,其根轨迹及相平面将发生变化,从而检测出小信号的存在。     

Sliding mode control for synchronization of chaotic systems with structure or parameters mismatching

INTRODUCTION Synchronization of chaotic systems and its ap-plication to secure communication has recently re-ceived much attention. Several chaos synchronization schemes have been successfully established (Liao and Huang, 1999; Jiang, 2002; Zhao et al., 2004). How-ever, to our best knowledge, most of the chaos syn-chronization strategies have been studied in similar oscillators. In fact, from the perspective of hardware implementation, the resistance and capacitance of the resistors and…     

Logistic映射在图像加密中的应用

分析了logistic映射的稳定点随参数变化的特性及其混沌特征,将logistic映射产生的混沌序列应用于图像加密/解密之中.设计的算法采用了两种不同表达方式的logistic映射所产生的两列混沌序列对图像进行加密.基于这种算法的混沌加密系统具有双参数,对初值极端敏感和不可预测性等优点.计算机仿真实验结果也表明了这种系统具有良好的安全性.