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1.
提出了混沌神经网络的动态阈值控制方法, 将大脑脑电波的主要成分, 正弦信号作为控制变量实现对混沌神经网络内部状态的阈值动态改变, 从而达到了控制混沌神经网络混沌的目的. 利用该方法可以将混沌神经网络的输出稳定在一个与网络初始模式相关的存储模式和其反相模式上, 从而使混沌神经网络在模式识别、信息搜索等信息处理功能得以实现. 该控制方法不需要事先指定阈值, 是一种自适应方法, 符合实际人脑的思维运动.
关键词:
混沌控制
混沌神经网络
动态阈值控制
信息处理 相似文献
2.
基于混沌时间序列的非线性自适应预测原理,用一种sigmoid-Volterra自适应预测滤波器研究了连续混沌系统的非线性自适应预测跟踪控制.通过对Lorenz,R?ssler等典型混沌系统的控制,仿真证实了这种sigmoid-Volterra自适应预测控制器的有效性.这种方法的优点在于它既不需要知道精确的混沌系统模型,也不需要进行系统模型辨识.
关键词:
混沌
sigmoid-Volterra自适应预测滤波器
非线性自适应预测跟踪 相似文献
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在混沌有益时,有目的地产生混沌已经成为混沌学研究的热点问题,本文提出直接延迟反馈实现混沌的反控制,在非混沌系统中产生了混沌.该方法与间接延迟反馈控制方法相比,控制更加简单,更易于实现.该方法与Pyragas提出的延迟反馈混沌控制方法的控制器结构相同,因此,这种直接延迟反馈控制方法可以在需要混沌时产生混沌,不需要混沌时控制混沌,实现混沌控制和反控制的统一,为设计者提供最大的灵活性.针对参数处于非混沌区的Chen系统和Lorenz系统的仿真结果表明了该混沌反控制方法的有效性.
关键词:
混沌
反控制
直接延迟反馈 相似文献
4.
对不确定混沌系统控制问题, 研究了一种基于径向基函数神经网络(radial basis function neural network, RBFNN)的反馈补偿控制方法. 该方法首先用RBFNN对混沌系统的动力学特性进行学习, 然后用训练好的RBFNN模型对混沌系统进行反馈补偿控制. 该方法的特点是不需要被控混沌系统的数学模型,可以快速跟踪任意给定的参考信号. 数值仿真试验表明了该控制方法不仅具有响应速度快、控制精度高, 而且具有较强的抑制混沌系统参数摄动能力和抗干扰能力. 相似文献
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针对不确定混沌系统控制问题, 研究了一种基于共轭梯度法(conjugate gradient algorithm, CGA)的多项式函数模型 (polynomial-basis-functions model, PBFM)的补偿控制方法. 该方法首先用PBFM对混沌系统的动力学特性进行拟合, 然后用拟合好的PBFM模型对不确定混沌系统进行前馈补偿控制. 该方法的特点是不需要被控混沌系统的数学模型, 可以快速跟踪任意给定的参考信号. 数值仿真试验表明了该方法不仅具有响应速度快、控制精度高, 而且具有较强的抑制混沌系统参数摄动能力和抗干扰能力.
关键词:
混沌控制
多项式函数模型
共轭梯度法 相似文献
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针对永磁同步电动机中存在的混沌运动,给出了一种基于冲洗滤波(washout filter)技术的永磁同步电动机混沌控制方法.该方法以永磁同步电动机的电流作反馈,实现了混沌运动的控制.该控制方法不影响原系统的参数,只需要调整滤波器的控制参数,算法简单、易于工程实现.数值仿真结果表明了该方法的有效性和鲁棒性.
关键词:
冲洗滤波器
永磁同步电动机
混沌控制 相似文献
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混沌系统的一般变结构控制方法存在高频抖振和需要事先已知系统不确定项的上界等不足,针对这些不足,以一类不确定时变混沌系统为例,提出了自适应无抖振变结构控制(ACFVSC)方法,以控制混沌系统到任意设定轨道.该方法不仅能消除滑模面附近的抖振现象,实现渐近跟踪,而且不需要“不确定项的上界已知”的先验知识.ACFVSC的渐近跟踪分析与仿真结果都表明,只要选择合适的控制器参数,就能在有限时间内达到任意的设定跟踪精度.
关键词:
不确定时变混沌系统
变结构控制
无抖振 相似文献
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Results of radionuclide activity concentration measurements in deposition and ground-level air conducted at the station of
the Institute of Physics situated 3.5 km from the Ignalina Nuclear Power Plant (Ignalina NPP) in 2005 are analyzed. Atmospheric
depositional fluxes of 7Be, 60Co and 137Cs are estimated. Radionuclide particle deposition rates are calculated. The Hybrid Single-Particle Lagrangian Integrated
Trajectory (HYSPLIT) model of the global dispersion and deposition is used to explain variations in the 137Cs activity concentration in the ground-level air in the Ignalina NPP region in 2005. An increase in the 137Cs activity concentration of up to 17.4 μBq m−3 on 30 October-5 November is studied. Modelling results show that the Chernobyl NPP Unit 4 Sarcophagus and the radiocaesium
resuspension from the Chernobyl NPP accident polluted regions are sources of 137Cs to the environment of the Ignalina NPP. Results on solubility in water of aerosols — carriers of 137Cs — are discussed. 相似文献
12.
In this paper, we investigate the data of industries in China and find that the frequency distributions of fixed assets and fixed-assets’ investment of industries obey power laws. We show that these power-law modes can be explained by the rules of the Simon Model, rather than the existing investment theories such as the classical investment theory or acceleration principle. Moreover, the mechanism of the investment distribution may be similar to the forest-fire model of self-organizing criticality. By introducing the complex system methods, this research changes the traditional opinion of the investment and gains some meaningful understanding in the dynamics of industries and the economic cycle. 相似文献
13.
V. I. Nazaruk 《The European Physical Journal A - Hadrons and Nuclei》2007,31(2):177-183
The role of strong absorption of particles in intermediate and final states has been considered. The range of applicability
of phenomenological models of absorption has been studied. This model is nonuniversal. Its applicability depends on the type
of interaction Hamiltonian and matrix element used. We also demonstrate that the violation of the unitarity condition can
produce a qualitative error in the results. The absorption (decay) in the final state does not tend to suppress the total
process probability as well as the probability of the channel corresponding to absorption. This is true for the reactions,
decays and nˉ conversion in the medium. 相似文献
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On phase-coherence in rescattering in multiphoton ionization and in higher-order harmonic generation
Summary The recently discovered plateau and rings in high-order multiphoton ionization apparently have their origin in rescattering.
Similarly, rescattering is involved in higher-order harmonic generation. Using a simple one-dimensional model, it is shown
that the phase-coherence in this rescattering process is of considerable importance.
The authors of this paper have agreed to not receive the proofs for correction.
This work has been supported by the East-West Program of the Austrian Academy of Sciences and by the Austrian Ministry of
Science and Transportation under project no. 45.372/2-IV/6/97. One of us (JZK) acknowledges the support of the Polish Committee
of Scientific Research (grant KBN 2 P03B 007 13). 相似文献
17.
Efficient frequency-doubling is experimentally demonstrated in presence of beam self-trapping in congruent lithium niobate crystal. The self-trapping is induced by the generated second harmonic beam via photorefractive effect under an external applied field. The local space charge field distribution, formed by the second harmonic beam, is shown to efficiently trap both wavelengths. The dynamics of self-focusing is studied along with the power evolution of the second harmonic beam. Fast tuning of phase matching conditions in the written waveguide is realized by an externally applied voltage also used for the photorefractive confinement. 相似文献
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An electron gas in crossed electric and magnetic fields of arbitrary strength is considered in the framework of nonequilibrium
statistical mechanics. It is known that more than one independent frequency existing in a system, which are of comparable
magnitude, can generate coherent synergic radiation. In the present system three independent frequencies exist: viz the synchrotron
frequency due to the magnetic field, the hopping frequency due to the electric field, and the plasma frequency. It is shown
that all these can combine to generate a new synergic coherent radiation. The results also show the possibility of interpreting
the quantum nature of Hall conductance as due to density function alone. Besides these, the solution admits the Schubnikov-de
Haas oscillation of the electrical conductivity due to change in the fields. 相似文献