我国证券市场的混沌与分形研究

最大李雅普诺夫指数和赫斯特指数分别是混沌和分形的重要指标,以深市和沪市的大盘日收盘价的对数收益率为研究对象,分别计算了深市和沪市的最大李雅普诺夫指数和赫斯特指数,验证了我国股市的混沌与分形的特性。     

我国证券市场的混沌与分形研究

最大李雅普诺夫指数和赫斯特指数分别是混沌和分形的重要指标，以深市和沪市的大盘日收盘价的对数收益率为研究对象，分别计算了深市和沪市的最大李雅普诺夫指数和赫斯特指数，验证了我国股市的混沈与分形的特性。     

一类非线性复杂网络的混沌动力学行为研究

基于系统最大李雅普诺夫指数的数学计算方法,从网络本身的拓扑结构出发,给出了一类非线性复杂网络对初始状态敏感的充分条件,同时仿真出网络所有李雅普诺夫指数随着时间推移的变化趋势图以及系统状态的相轨迹图,成功实现了网络的混沌反控制。     

下喷自吸环流反应器内局部混沌特性(英文)

应用确定性混沌分析技术,初步研究了下喷自吸环流反应器内气－液两相流动的时序压力波动的局部混沌特性．结果发现,在本文实验条件下,该反应器内局部最大李雅普诺夫指数值均大于零,并且呈现出与局部分形维数类似的分布规律．这些结果表明,该反应器内的流动行为呈现混沌特性,可以应用诸如局部最大李雅普诺夫指数和局部分形维数等局部非线性特征参数从更深层上揭示多相反应器内的流动特性,例如流区过渡及流动结构等．     

不同混沌源调制信号降低Boost型变换器电磁干扰水平研究

以Boost型DC／DC变换器为对象，研究在同一混沌调制模式下，不同混沌源对降低开关电源电磁干扰水平效果的影响。仿真结果表明：不同混沌源调制信号有不同的降低电磁干扰水平效果，Lorenz混沌源降低电磁干扰水平的效果较好。     

Lorenz混沌调频雷达信号性能分析

为了提高雷达系统的性能,克服因离散混沌调频信号李雅普诺夫指数小造成混沌特性差的缺点,提出了Lorenz混沌调频信号.通过经初值优化处理后的Lorenz连续混沌系统产生该调频信号,将其应用于雷达中.从自相关、抗干扰能力、相图3个方面对Lorenz混沌调频雷达信号进行了仿真对比分析.仿真结果表明,Lorenz混沌调频雷达信号提高了雷达的测距精度、成像质量和抗干扰能力.     

自由电子激光中的电子和光场的混沌

针对康普顿型常参数自由电子激光器的理论模型,应用运动轨道直接观测法,绘制了电子相轨道的二维投影构图,并计算了轨道的李雅普诺夫(Lyapunon)指数.确定了电子混沌轨道的临界区域.     

混沌同步化的线性反馈理论

对于Lorenz系统用李雅普诺夫函数方法构造了两种线性反馈函数形式,研究了实现混沌同步化的线性理论     

混沌同步化的非线性反馈方法

对于Loremz系统用李雅普诺夫函数方法构造了几种非线性反馈函数形式,讨论了实现混沌同步化的非线性方法.     

两个异结构超混沌Liu系统的同步研究

研究两个不同结构超混沌Liu系统的同步问题彳4用非线性控制方法,构建了实现它们同步非线性控制器．借助于李雅普诺夫稳定性定理,从理论上证明了同步误差系统是全局渐近稳定的．Matlab数值仿真结果表明所设计的非线性控制器能有效地实现超混沌Liu系统同步．     

Lyapunov指数计算研究及应用

Lyapunov指数是判定系统是否处于混沌状态的简捷方法之一,但计算Lyapunov指数的诸多方法普遍存在精度不高、受噪声影响大且计算量大等问题而使应用受到限制。借助计算机代数系统Maple建立基于Wolf算法的Lyapunov指数的机械化算法,可以方便地计算Lyapunov指数,从而可以迅速判定系统的混沌性。     

Nonlinear dynamics analysis of a new autonomous chaotic system

In this paper,a new nonlinear autonomous system introduced by Chlouverakis and Sprott is studied further,to present very rich and complex nonlinear dynamical behaviors. Some basic dynamical properties are studied either analytically or nu-merically,such as Poincaré map,Lyapunov exponents and Lyapunov dimension. Based on this flow,a new almost-Hamilton chaotic system with very high Lyapunov dimensions is constructed and investigated. Two new nonlinear autonomous systems can be changed into one another by adding or omitting some constant coefficients.     

English-medium teaching in Korean higher education: policy debates and reality

This study critically examined the effectiveness of English medium instruction (EMI) policy within the context of Korean higher education, putting a special focus on its implementation strategy. The data for this study were mainly drawn from student opinion surveys and focus group interviews conducted by the CTL (Center for Teaching and Learning) at KU. The research teams also carried out supplementary interviews with both professors and students. The results indicate that, although the EMI policy seems to have produced, in general, positive outcomes (i.e., with the overall satisfaction level with EMI or its overall effectiveness in improving students’ English proficiency), the compulsory enforcement of EMI without regard to students’/instructors’ language proficiency, the lack of a much-needed support system and appropriate instructors to conduct EMI classes, and the unilateral implementation of EMI across academic disciplines have brought about a number of side effects. Based on these findings, the study recommends for future EMI policy implementation (1) a more flexible approach, considering students’ language proficiency and career plans and the characteristics of various academic disciplines and (2) more thorough preparation to implement the EMI policy (i.e., examination of the human and financial resources available for the institution concerned).     

基于最小晶体管的非自主混沌电路

提出了由一个晶体管、两个电容和两个电阻组成的非自主混沌电路，混沌行为基于积分干扰以及双极性晶体管两极对电容正一反向的充电，调节振荡器的频率得到了完整的混沌仿真波形，并通过PSpice软件计算了李雅诺夫指数，证实了混沌特性。     

我国股票指数混沌行为测试

本文对我国股市是否存在混沌行为进行分析,运用Lyapunov指数和自相关函数对股票指数的历史数据进行了计算测试,得出我国股票指数具有混沌特征的结论。     

English as a medium of instruction at a Chilean engineering school: Experiences in finance and industrial organization courses

Implementing English as a medium of instruction (EMI) in Latin American countries contributes to reducing language exchange isolation in the region and helps prepare higher education students for future labor opportunities. However, one of the main concerns around EMI is whether English instruction could negatively affect content acquisition. This paper examines if the performance of native Spanish speakers is affected by EMI. Specifically, it discusses experiences from finance and industrial organization courses given to industrial engineers at a Chilean university. The results of a multivariate analysis of tests and final grades show that performance differences can mainly be attributed to students’ performance in previous courses; only on rare occasions do language, gender, and attendance explain performance differences.     

Chaotic phenomenon and the maximum predictable time scale of observation series of urban hourly water consumption

The chaotic characteristics and maximum predictable time scale of the observation series of hourly water consumption in Hangzhou were investigated using the advanced algorithm presented here is based on the conventional Wolf's algorithm for the largest Lyapunov exponent. For comparison, the largest Lyapunov exponents of water consumption series with one-hour and 24-hour intervals were calculated respectively. The results indicated that chaotic characteristics obviously exist in the hourly water consumption system; and that observation series with 24-hour interval have longer maximum predictable scale than hourly series. These findings could have significant practical application for better prediction of urban hourly water consumption.     

Chaotic phenomenon and the maximum predictable time scale of observation series of urban hourly water consumption

The chaotic characteristics and maximum predictable time scale of the observation series of hourly water consumption in Hangzhou were investigated using the advanced algorithm presented here is based on the conventional Wolf's algorithm for the largest Lyapunov exponent. For comparison, the largest Lyapunov exponents of water consumption series with one-hour and 24-hour intervals were calculated respectively. The results indicated that chaotic characteristics obviously exist in the hourly water consumption system; and that observation series with 24-hour interval have longer maximum predictable scale than hourly series. These findings could have significant practical application for better prediction of urban hourly water consumption.