共查询到18条相似文献,搜索用时 203 毫秒
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基于参数切换算法和离散混沌系统, 设计一种新的混沌系统参数切换算法, 给出了两算法的原理. 采用混沌吸引子相图观测法, 研究了不同算法下统一混沌系统和Rössler混沌系统参数切换结果, 最后引入方波发生器, 设计了Rössler混沌系统参数切换电路. 结果表明, 采用参数切换算法可以近似出指定参数下的系统, 其吸引子与该参数下吸引子一致; 基于离散系统的参数切换结果更为复杂, 当离散序列分布均匀时, 只可近似得到指定参数下的系统; 相比传统切换混沌电路, 参数切换电路不用修改原有系统电路结构, 设计更为简单, 输出结果受方波频率影响, 通过加入合适频率的方波发生器, 数值仿真与电路仿真结果一致. 相似文献
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Lyapunov指数是判定系统非线性行为的重要工具,然而目前的大多算法并不适用于切换系统.在传统Jacobi法的基础上,提出了一种新算法,可以直接计算得到n维切换系统的n个Lyapunov指数.首先,根据切换面处相邻轨线的动态变化规律,从相空间几何推导出切换面处轨线变化的Jacobi矩阵;然后,对该矩阵进行QR分解,从而利用R的对角线元素实现Lyapunov指数的切换补偿;最后,将新算法应用到平面双螺旋混沌系统、Glass网络和航天器供电系统三个实例中,并将计算结果与Poincaré映射方法的计算结果进行比较,对新算法的有效性进行验证. 相似文献
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从混沌与分形的关系出发,基于奇怪吸引子的分形结构和时间序列的自仿射特性,提出了一种混沌时间序列的预测方法.采用迭代函数系统跟踪混沌的局部运动轨迹,由此确定统计意义上仿射性能最优的时间序列段,并根据吸引子定理和拼贴定理建立预测模型.以Mackey-Glass混沌系统、脑电信号和Lorenz混沌系统等三种混沌系统为例进行预测试验,结果表明本方法能对混沌时间序列进行准确预测,且对混沌时间序列先验知识要求少,具有广泛的实用性.
关键词:
自仿射
迭代函数系统
混沌时间序列
预测 相似文献
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基于电流密度拉普拉斯变换方法改进的时域有限差分(LTJEC-FDTD)算法, 研究时变等离子体目标的电磁散射特性.由Maxwell方程和等离子体本构方程出发, 利用拉普拉斯变换和拉普拉斯逆变换, 推导出计算三维时变问题的时域有限差分(FDTD)算法的迭代式. 采用模式匹配方法验证了FDTD迭代式的正确性, 并通过计算等离子体球的雷达散射截面(RCS)验证了算法相关边界的正确性. 最后用LTJEC-FDTD算法分析了涂覆时变等离子体的战斧式巡航导弹的RCS.
关键词:
时变等离子体
雷达散射截面
模式匹配方法
时域有限差分方法 相似文献
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为了避免基于有限更新率的连续域信号采样涉及复杂的运算问题,认真研究分段线性序列特点,提出一种在离散域进行信号参量提取的方法,称之为序列重采样.给出了有限长序列更新率定义,总结出一种适合简单分段线性序列的参量提取算法——试探法,将之推广到一般分段线性序列.不需要事先知道更新率的数量,也不需要在连续域进行运算,从采样后的序列中直接检测信号更新点和更新参量,从而实现信号采样.对所提出的算法进行了仿真,结果表明该算法是有效的. 相似文献
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Approximation-error-ADP-based optimal tracking control for chaotic systems with convergence proof
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In this paper, an optimal tracking control scheme is proposed for a class of discrete-time chaotic systems using the approximation-error-based adaptive dynamic programming (ADP) algorithm. Via the system transformation, the optimal tracking problem is transformed into an optimal regulation problem, and then the novel optimal tracking control method is proposed. It is shown that for the iterative ADP algorithm with finite approximation error, the iterative performance index functions can converge to a finite neighborhood of the greatest lower bound of all performance index functions under some convergence conditions. Two examples are given to demonstrate the validity of the proposed optimal tracking control scheme for chaotic systems. 相似文献
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Vehicle-to-everything (V2X) communication is essential for intelligent transportation systems (ITS) and critical technology to ensure traffic safety. Aiming at the problems of noise interference, time-varying, and inter-carrier interference (ICI) in the LTE-V2X channel, a joint fast time-varying channel estimation with noise elimination and ICI cancellation is proposed in this paper. Firstly, using the autocorrelation characteristics of the Zadoff Chu (ZC) pilot sequence, a modified discrete Fourier transform (M-DFT) channel estimation algorithm is proposed to eliminate the noise in cyclic prefix (CP). Secondly, a joint iterative direct decision (IDD) and time-varying channel fitting (CF), called IDD-CF channel estimation algorithm, is proposed to track the rapid changes of channels on different symbols and eliminate ICI. The system simulation results show that the proposed joint fast time-varying channel estimation algorithm can effectively eliminate the noise and ICI, improve the performance of channel estimation, and have better robustness under different Doppler frequency shifts than the representative channel estimation algorithm. 相似文献
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针对复杂环境下的追踪控制问题,提出了一种基于连续时间广义预测校正的水下非线性追踪博弈控制算法.利用连续时间广义预测对目标机动偏离趋势进行在线预测补偿校正,将机动目标紧缩于最大捕获概率扇面之内,同时引入零效控制参数和连续时间广义预测校正算法,解决了微分对策动态博弈剩余时间难于估计的问题,提高了系统的响应速度.将算法应用于水下非线性追踪博弈的验证结果表明,该算法兼顾了控制约束与干扰抑制性能,能够实时有效地对抗初始偏差和随机扰动,不仅具有良好的导引效果,而且有效提高了系统对环境干扰的鲁棒性. 相似文献
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In this paper, we use finite element methods to simulate the hydrodynamical systems governing the motions of nematic liquid crystals in a bounded domain Ω. We reformulate the original model in the weak form which is consistent with the continuous dissipative energy law for the flow and director fields in W1,2+σ(Ω) (σ > 0 is an arbitrarily small number). This enables us to use convenient conformal C0 finite elements in solving the problem. Moreover, a discrete energy law is derived for a modified midpoint time discretization scheme. A fixed iterative method is used to solve the resulted nonlinear system so that a matrix free time evolution may be achieved and velocity and director variables may be solved separately. A number of hydrodynamical liquid crystal examples are computed to demonstrate the effects of the parameters and the performance of the method. 相似文献
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针对变水量空调系统温度控制的时变、大滞后、非线性特点,结合模糊控制和PID控制,设计了基于模糊规则切换的Fuzzy-PID分级控制器,并在Matlab/Simulink软件上进行了仿真。仿真结果表明,控制器同时具有模糊控制超调量小、鲁棒性好和PID控制精度高、响应速度快的优点。 相似文献
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J.S. WAUG 《Molecular physics》2013,111(5):731-735
The rearrangement of initial magnetic polarizations in a small isolated spin system does not lead to a uniform distribution as required by the microcanonical ensemble, but to a distribution of intermediate entropy as required by the initial conditions and auxiliary constants of the motion. The final equilibriumstate and the time to reach it are defined uniquely because of the finite number of discrete quantum states in such a system. Is such a system ergodic? 相似文献