混沌系统的延时全维混合投影同步

研究了参数未知混沌系统的全维混合投影同步.考虑到系统中存在延时,结合自适应控制策略和反馈控制方法,设计控制器和参数自适应更新函数,实现不同结构混沌系统的投影同步.数值仿真结果证实了本文提出的控制策略的有效性.     

异结构混沌系统同步控制的仿真研究

考虑到目前混沌同步问题主要研究结构相似的混沌系统之间同步控制的现状,本文提出运用非线性控制定律实现两个异结构混沌系统的同步控制,实现了新的混沌系统和一类统一混沌系统的同步控制.并运用非线性控制定律设计控制函数,得到了控制系数的稳定范围.采用Matlab进行数字仿真表明该同步控制方法的可行性.又利用EWB设计模拟电路,结果与Matlab的仿真结果吻合,更进一步证明了该同步方法的有效性.     

基于扩张状态观测器的四旋翼积分滑模反步控制

针对四旋翼路径跟踪控制问题,研究了基于扩张状态观测器(extended state observer,ESO)、积分滑模控制器(integral sliding mode controller,ISMC)及反步法(backstepping)的四旋翼控制算法。构造了一种考虑姿态控制器响应过程的无人机控制模型;设计了扩张状态观测器对扰动进行观测,并构建了积分滑模控制器以估计扰动观测误差;设计了基于反步法的抗干扰路径跟踪控制算法,利用扩展状态观测器估计的扰动信息,通过补偿方式较好地消除了扰动影响。仿真试验表明,该方法具有良好的轨迹跟踪性能和抗干扰能力。     

异结构超混沌系统的反同步

采用主动控制法和非线性控制法实现了超混沌Chert系统和超混沌Qi系统的不同结构间的反同步,设计了不同的控制器,使得两个超混沌系统实现异构反同步.基于线性系统稳定性原理,运用主动控制法来判别误差动态系统的稳定性;通过构造Lyapunov函数,运用了非线性控制法使两个超混沌系统得以反同步.数字仿真模拟验证了方法的有效性和可行性.     

离散和分布时变时滞混沌神经网络广义投影同步

研究一类离散和分布时变时滞的混沌神经网络的广义投影同步问题.利用非线性观测器方法实现同步十分简单,且利用极点配置技术,可通过调整特征值来调节同步速率的快慢.与一般混沌神经网络模型相比,带有离散和分布时变时滞的混沌神经网络模型更为一般,同时反同步和完全同步是广义投影同步的特例.最后,提出基于广义投影同步的离散和分布时变时滞混沌神经网络的保密通信方案,给出两个数值仿真例子验证结果的有效性.     

Adaptive Anti-Synchronization Between Different Chaotic/Hyperchaotic Systems with Fully Unknown Parameters

The anti-synchronization between different chaotic/hyperchaotic systems with fully unknown parameters is considered in detail. Based on Lyapunov stability theory, the adaptive control schemes and parameter update rules are designed in this paper. Two numerical examples show the effectiveness and feasibility of the proposed method.     

系统参数完全未知的一个新超混沌系统自适应修正投影同步

基于Lyapunov稳定性原理,在驱动系统和响应系统参数完全未知的情况下,设计自适应控制器和参数更新准则,使得两个不同或相同混沌系统同步,并能辨识出系统参数,同时可以通过调节控制增益和自适应增益来调整同步速度和参数辨识速度.作为该方法的应用,对超混沌Chen系统和一个新的超混沌系统实现了修正投影同步.数值仿真证明了所提方法的正确性.     

An Improving Indexing Approach on Time Series Based on Minimum Bounding Rectangle

A fundamental problem in whole sequence matching and subsequence matching is the problem of representation of time series. In the last decade many high level representations of time series have been proposed for data mining which involve a trade-off between accuracy and compactness. In this paper the author proposes a novel time series representation called Grid Minimum Bounding Rectangle (GMBR) and based on Minimum Bounding Rectangle. In this paper, the binary idea is applied into the Minimum Bounding Rectangle. The experiments have been performed on synthetic, as well as real data sequences to evaluate the proposed method. The experiment demonstrates that 69%- 92% of irrelevant sequences are pruned using the proposed method.     

基于荷载传递法的单桩沉降解析解

针对轴向荷载作用下的单桩工作特性,基于荷载传递法,采用了描述桩-土相互作用特性的双折线荷载传递函数,得到了针对桩-土变形全过程的单桩荷载-沉降关系解析解.利用该解析解,计算了具体案例,讨论了模型参数的取值范围,计算结果与实验曲线吻合较好.结果表明,本文方法能较好地描述单桩荷载传递过程,根据静载实验获得的具体参数,计算轴向荷载作用下单桩荷载-沉降关系,并估算单桩的承载力,为桩基础设计提供参考依据.     

Modified Projective Synchronization of a New Hyperchaotic System with Known or Unknown Parameters

This work presents two different methods-- nonlinear control method and adaptive control approach to achieve the modified projective synchronization of a new hyperchaotic system with known or unknown parameters. Based on Lyapunov stability theory, nonlinear control method is adopted when the parameters of driving and response systems are known beforehand; when the parameters are fully unknown, adaptive controllers and parameters update laws are proposed to synchronize two different hyperchaotic system and identify the unknown parameters. Moreover, the rate of synchronization can be regulated by adjusting the control gains designed in the controllers. The corresponding simulations are exploited to demonstrate the effectiveness of the proposed two methods.