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1.
混沌时间序列的Volterra自适应预测   总被引:20,自引:1,他引:19       下载免费PDF全文
张家树  肖先赐 《物理学报》2000,49(3):403-408
基于混沌动力系统相空间的延迟坐标重构,提出了一种预测混沌时间序列的Volterra自适应滤波预测法,对8种低维混沌序列采用二阶Volterra自适应滤波器进行预测的实验结果表明:当滤波器的长度Nl足够大时,Volterra自适应滤波器能够有效地预测低维混沌时间序列,且Nl的选择不仅与D2有关,还与混沌映射的光滑程度有关 关键词:  相似文献   

2.
基于Takens的相空间延迟坐标重构,研究了用于混沌信号预测的三阶Volterra滤波器的一种乘积耦合近似实现结构,并应用于典型的低维混沌时间序列和具有高维混沌特性的EEG信号的预测.数值研究表明:这种滤波器结构对于低维混沌时间序列的预测精度可以比二阶Volterra滤波器提高103倍,而且能够较好地对一些具有高维混沌特性的EEG信号进行预测 关键词: 混沌 非线性自适应预测 三阶Volterra滤波器 electroencephalography信号  相似文献   

3.
张家树  肖先赐 《物理学报》2001,50(7):1248-1254
研究了二阶Volterra滤波器的一种乘积耦合近似实现结构及其非线性NLMS自适应算法,并用这种少参数二阶Volterra滤波器(RPSOVF)研究了一些混沌信号的非线性自适应预测性能.仿真研究结果表明:所给出的非线性NLMS自适应算法能够保证这种RPSOVF的稳定性和收敛性,且RPSOVF用这种非线性NLMS自适应算法能够自适应预测一些混沌时间序列. 关键词: 混沌 非线性自适应预测 Volterra滤波器 非线性NLMS自适应算法  相似文献   

4.
依据相空间邻近轨道演化相似性特点建立训练模式,提出了基于自适应高阶非线性Volterra滤波器(HONFIR)的混沌时间序列多步预测模型(MSP-HONFIR);通过定义距离相似度、趋势相似度来衡量轨道演化相似度,提出了混沌吸引子邻近轨道判别的新方法;从模型训练充分性角度出发探讨了MSP-HONFIR滤波器模型训练集规模控制的依据.数值研究表明MSP-HONFIR滤波器模型的多步预测性能优于原有HONFIR滤波器模型. 关键词: 混沌 非线性自适应预测 Volterra滤波器模型 训练模式  相似文献   

5.
风电功率时间序列混沌特性分析及预测模型研究   总被引:5,自引:0,他引:5       下载免费PDF全文
张学清  梁军 《物理学报》2012,61(19):190507-190507
为揭示风电功率序列内在的动态特性, 利用非线性方法对风电时间序列混沌特性进行识别, 为对风电功率进行预测提供了基础.首先对某风电场的风电功率时间序列的日相关性进行了分析;然后在相空间重构的基础上计算了风电序列的最大Lyapunov指数, 验证了风电时间序列的混沌特性;由于采用Volterra滤波器多步预测法对风电功率进行超短期预测误差较大, 利用局域多步预测法以及最大Lyapunov指数法的预测结果并结合加权马尔科夫链和有序算子对Volterra滤波器的预测结果进行校正.最后以某实际风电场的风电功率预测为算例, 仿真结果表明校正预测模型有效的提高了预测精度, 其为利用Volterra滤波器多步法进行风电预测提供了有益的参考.  相似文献   

6.
供热负荷时间序列混沌特性分析及预报模型研究   总被引:1,自引:0,他引:1       下载免费PDF全文
张永明  齐维贵 《物理学报》2011,60(10):100508-100508
为揭示供热负荷时间序列蕴含的内在动态特性,采用非线性分析方法对供热负荷时间序列混沌特性进行识别.以集中供热热源和热力站负荷时间序列为研究对象,进行相空间重构,求得了饱和关联维数和最大Lyapunov指数,验证了供热负荷时间序列的混沌特性,为供热负荷预报研究提供了混沌理论基础.针对现有供热负荷预报方法多为主观模型方法,本文提出了一种基于Volterra自适应滤波器的供热负荷预报方法,该方法不必事先建立主观模型,而直接根据负荷序列本身的特性进行预报,避免了负荷预报的人为主观性.最后,给出了供热负荷预报算例,仿真结果表明二阶Volterra自适应滤波器模型预报精度较高,可满足供热工程节能控制及热力调度的需要. 关键词: 供热节能 负荷预报 混沌 Volterra自适应滤波器  相似文献   

7.
非线性时间序列的小波分频预测   总被引:5,自引:0,他引:5       下载免费PDF全文
雷明  韩崇昭  郭文艳  文小琴 《物理学报》2005,54(5):1988-1993
基于噪声的小波变换特点,结合小波包分解和模极大重构来抽取含噪信号的主分量,提出了一种基于最佳尺度分解和Volterra自适应滤波的分频预测算法,使用较少的模型训练样本,同时具有强的抗噪能力.该算法克服了传统小波分解尺度选取的盲目性及单纯Volterra预测器抗噪性能的不足,数值仿真表明,针对含强噪声的非线性信号可进行有效预测. 关键词: 小波分解 Volterra自适应滤波器 分频预测  相似文献   

8.
李颖  陈兴林 《光子学报》2009,38(1):94-98
提出采用投影寻踪网络逼近Volterra滤波器的方法以实现光纤陀螺输出信号非线性噪声消除.投影寻踪网络采用批量学习和参数交替优化的训练算法,可以自适应确定神经网络的规模、参数和神经元函数,具有简捷的网络结构和较强的鲁棒性,克服了Volterra滤波器随着阶数增加,滤波系数的数量呈几何级数增长,实现困难的问题.仿真结果表明PPLN网络滤波器比Volterra滤波器具有更好的消噪效果.  相似文献   

9.
单极型马赫-曾德尔调制器的互调失真分析   总被引:7,自引:2,他引:5  
池灏  章献民  沈林放 《光学学报》2006,26(11):619-1622
针对单极型马赫曾德尔电光调制器在Radio over Fiber(RoF)和副载波复用系统中的应用,讨论了输入两路射频信号的情形,给出了电光调制器互调失真的严格通用解析解。该解析解可用于表示任意阶的互调失真项和谐波项。数值结果表明了该解析解的正确性。分析结果表明,调制器的三阶互调失真与调制器偏置相移无关,只与输入射频信号的调制系数有关,并且当外加偏置电压等于调制器的半波电压时,只存在偶数阶的失真项。根据该解析解,可方便地设计模拟光通信系统,精确地预计外调制器的非线性特征,优化系统性能。  相似文献   

10.
一种基于光纤光栅的毫米波副载波光纤通信方案   总被引:10,自引:0,他引:10  
叶青  刘峰  瞿荣辉  方祖捷 《光学学报》2006,26(10):464-1468
提出了一种采用光纤光栅滤波器获得具有一定间隔双波长成分的光脉冲光谱实现毫米波副载波光信号产生的方法。利用逆工程算法,设计了一种变迹叠栅(Moiré)光纤光栅滤波器,给出了相应的模拟结果;并在实验上初步制作了相应的光纤光栅滤波器,验证其可行性。同时基于所设计的光纤光栅和波分复用技术,提出了一种频移键控光纤无线通信系统Radio Over Fiber系统,为下一代的高速大容量的光纤无线通信系统系统提供一种可行的备选解决方案。  相似文献   

11.
Neural Volterra filter for chaotic time series prediction   总被引:1,自引:0,他引:1       下载免费PDF全文
李恒超  张家树  肖先赐 《中国物理》2005,14(11):2181-2188
A new second-order neural Volterra filter (SONVF) with conjugate gradient (CG) algorithm is proposed to predict chaotic time series based on phase space delay-coordinate reconstruction of chaotic dynamics system in this paper, where the neuron activation functions are introduced to constraint Volterra series terms for improving the nonlinear approximation of second-order Volterra filter (SOVF). The SONVF with CG algorithm improves the accuracy of prediction without increasing the computation complexity. Meanwhile, the difficulty of neuron number determination does not exist here. Experimental results show that the proposed filter can predict chaotic time series effectively, and one-step and multi-step prediction performances are obviously superior to those of SOVF, which demonstrate that the proposed SONVF is feasible and effective.  相似文献   

12.
Wei Ji  Woon-Seng Gan 《Applied Acoustics》2012,73(12):1251-1262
Due to the parametric acoustic array effect in air, the input audible signal of a parametric loudspeaker system can be reproduced with high directivity at the target region. However, the reproduced audible signal suffers from harmonic distortion, which is the by-product of nonlinear interaction between the primary waves. In order to investigate this inherent nonlinear phenomenon, a nonlinear system identification model is developed based on an adaptive Volterra filter. Unlike the conventional loudspeaker, the nonlinear characteristic of a parametric loudspeaker system is dependent on several primary parameters in nonlinear acoustics, which include the initial pressure of the primary waves, the observing distance and angle, as well as ambient temperature and relative humidity. By using a truncated Volterra series up to the 2nd-order kernel, numerical simulations are conducted to develop a system model with one group of parameters and examine the quadratic nonlinear intensity for different parameters’ settings. Experimental measurements, which take into account of emitter’s response, are carried out to verify the modeling result and evaluate the model performance. Based on the Volterra system model, the sound pressure level and the harmonic distortion can be accurately predicted.  相似文献   

13.
This paper proposes a nonlinear active noise control (ANC) system based on convex combination of a functional link artificial neural network (FLANN) and a Volterra filter. Simulation study reveals enhanced noise cancelation performance of the proposed ANC system over the ones based on its component filters.  相似文献   

14.
离焦模糊图像的维纳滤波恢复   总被引:4,自引:0,他引:4  
为消除离焦误差产生的图像模糊,介绍了基于逆滤波和维纳滤波的离焦模糊图像复原方法。从光学成像原理出发,根据高斯方程计算离焦误差,建立离焦误差与光学传递函数之间的关系。讨论了离焦误差对光学成像系统传递函数的影响。通过建立线性空间不变的模糊模型,构建点扩散函数和光学传递函数,采用与模糊过程相反的处理方法进行图像复原,消除离焦误差造成的图像模糊。测试实验中,对标准样本Lena图像进行了离焦模糊处理,采用维纳滤波算法复原图像,选择不同的离焦半径和维纳滤波参数进行对比。实验结果表明:维纳滤波方法可有效消除离焦模糊;抑制噪声干扰和"振铃效应";可把图像峰值信噪比提高到6dB以上。  相似文献   

15.
A parametric loudspeaker utilizes nonlinearity of a medium and is known as a super-directive loudspeaker. In this paper, the sound localization in the vertical direction using the upper and lower parametric loudspeakers is confirmed by listening tests and physical measurements. The differences in levels between the upper and lower parametric loudspeakers are varied as a parameter. The direction of sound localization in the vertical plane can be controlled not only when the acoustical axis is set to the right ear but also when it is set to at 5 deg to the right of the right ear. The effect of the level difference between the upper and lower loudspeakers is weaker than the differences observed when using ordinary loudspeakers. We obtained interesting characteristics of the left-right sound localization in the horizontal plane with the upper and lower parametric loudspeakers in the vertical plane. It is found that by setting the parametric loudspeaker at the right ear (that is, the horizontal angle of a listener to it is only 3 deg to the right), the direction of sound localization in the horizontal plane moved approximately 10 deg to the right. Moreover, by setting the parametric loudspeaker 5 deg to the right, the direction of sound localization moves approximately 20 deg to the right. The ILD (Interaural Level Difference) using a dummy head is calculated from the measured left and right sound signals. It is determined that ILDs of the parametric loudspeaker are larger than those of the ordinary loudspeaker. A simple geometrical acoustic model is introduced and analyzed. The analysis helps to explain the measured characteristics.  相似文献   

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