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1.
贾飞蕾  徐伟  都林 《物理学报》2007,56(10):5640-5647
采用扩阶方法(使响应系统和驱动系统的维数相同),把不同阶数混沌系统的广义同步问题转化为相同阶数混沌系统之间的广义同步,基于Lyapunov稳定性定理和自适应控制方法(用于相同阶数混沌系统的同步),给出了自适应控制器和参数自适应律,进而实现了不同阶数混沌系统的广义同步.将该方法应用于参数未知的超Lü,Lorenz,广义Lorenz和Liu等系统之间的广义混沌同步,理论证明了该方法可以使这些系统达到渐近广义同步,并且可以辨识驱动系统和响应系统的所有参数,数值模拟进一步证明了该方法的有效性.  相似文献   

2.
朱志宇 《物理学报》2006,55(12):6248-6252
应用精确线性化方法,通过严格的状态变换和反馈方法,将非线性混沌系统线性化. 考虑到系统的部分状态变量无法测量,设计了混沌系统的状态观测器,求解出了状态观测器的反馈控制律. 将这种控制方法应用于Lorenz混沌系统的同步控制,仿真结果表明,系统三个状态变量的同步误差均能在很短的时间内收敛到零.因此,该同步控制方法在保证闭环系统稳定的前提下,具有较好的同步控制快速性和较高的控制精度. 关键词: 反馈线性化 混沌同步 状态观测器  相似文献   

3.
基于观测器的混沌系统的同步研究   总被引:10,自引:1,他引:9       下载免费PDF全文
提出了一类混沌系统的观测器同步方法.利用混沌系统的状态观测器,给出了一类混沌系统 观测器的同步的简单有效的方法,并分析了系统的稳定性,通过对Lorenz混沌系统的分析和 数值模拟研究,验证了该方法在混沌同步中的优良性能. 关键词: 混沌系统 混沌同步 状态观测器  相似文献   

4.
针对寿命服从指数分布的随机截尾样本,研究单元及系统可靠度的评估方法,给出了系统可靠度置信下限估计方法,该方法同样适用于工程中常见的定时截尾样本与定数截尾样本的系统可靠度评估问题。首先通过分位数填充算法将随机截尾数据补充成虚拟完全样本,然后基于信仰推断,给出系统内每个单元失效率的信仰分布,最后根据指数分布的特点,从失效率角度出发,采用蒙特卡罗法对单元失效率进行随机抽样,结合系统可靠性模型得到系统失效率的分布,在给定置信水平下即可得到系统失效率上限,进而得到工程上特别关注的系统可靠度置信下限。  相似文献   

5.
Liu混沌系统的非线性反馈同步控制   总被引:48,自引:0,他引:48       下载免费PDF全文
陈志盛  孙克辉  张泰山 《物理学报》2005,54(6):2580-2583
研究了新型混沌系统——Liu系统的同步控制问题.基于Lyapunov稳定性理论,采用非线性反馈控制方法,给出了Liu系统实现自同步的充分条件以及控制律参数的取值范围;结合参数自适应控制方法,实现了Liu混沌系统与统一混沌系统的异结构系统快速同步.数值仿真证明了该方法的有效性. 关键词: Liu混沌系统 混沌同步 非线性反馈控制 参数自适应控制  相似文献   

6.
一类混沌系统的非自治反馈控制   总被引:1,自引:0,他引:1       下载免费PDF全文
蒋书敏  田立新 《物理学报》2006,55(7):3322-3327
提出一种自治系统的非自治反馈控制方法,并利用非自治系统的稳定性理论证明了该方法的正确性,最后就江苏-西部能源需求-供给模型及Arneodo系统进行了数值仿真,结果表明该方法是正确可行的. 关键词: 自治系统 非自治反馈控制 Lyapunov函数  相似文献   

7.
Liu混沌系统的线性反馈同步控制及电路实验的研究   总被引:2,自引:0,他引:2       下载免费PDF全文
王发强  刘崇新 《物理学报》2006,55(10):5055-5060
研究了新型混沌系统——Liu混沌系统的同步控制问题,基于Liu混沌系统的混沌特性,采用线性反馈控制方法,给出了实现Liu混沌系统同步的控制参数取值范围,数值仿真和电路实验证实了该方法的有效性. 关键词: Liu混沌系统 线性反馈控制 混沌同步 电路  相似文献   

8.
相似耦合系统的统计能量分析   总被引:5,自引:0,他引:5  
根据相关或互不相关激励条件下非保守耦合系统的统计能量分析原理,建立了两个相似的SEA系统之间的能量关系,提出了由已知系统预估未知相似系统的SEA方法。通过对保守和非保守耦合情况下板-梁和板-边框两个相似耦合系统的研究,分别从理论和实验上论证了这种方法的合理性。作为方法的应用,本文研究了两个相似切削系统的切削噪声问题,研究结果表明,理论分析和实验结果有很好的一致性,该方法可以有效地用于复杂耦合系统动态问题的研究。  相似文献   

9.
一类参数不确定统一混沌系统的脉冲滞后同步   总被引:1,自引:0,他引:1       下载免费PDF全文
马铁东  张化光  王智良 《物理学报》2007,56(7):3796-3802
针对一类具有传输信道时间延迟且参数不确定的统一混沌系统,提出了一种脉冲控制同步方法.该方法将两个非自治混沌系统之间脉冲同步的实用稳定性问题转化为同步误差系统在原点的实用稳定性问题,基于脉冲微分方程的相关理论,给出了同步误差系统在原点的实用稳定判据,仿真结果验证了方法的有效性. 关键词: 统一混沌系统 混沌同步 脉冲控制 实用稳定性  相似文献   

10.
混沌的自适应控制   总被引:12,自引:0,他引:12       下载免费PDF全文
童培庆 《物理学报》1995,44(2):169-176
提出了控制二维动力学系统中分贫和混沌的自适应方法,给出控制强度的选取方法,并且对两个动力学系统-Henon映射和强迫布鲁塞尔振子的分岔和浊进行了控制,取得了很好的结果,最后,将此方法与(OGY)ott,Grebogi,Yorke缩写为控制方法进行了比较,讨论了将此方法推广到高维系统以及方程未知的动力学系统的可能性。  相似文献   

11.
The storage of long bunches for long time intervals needs flattened stationary buckets with a large bucket height. The longitudinal motion of the initially mismatched beam has been studied for both the single and dual harmonic RF systems. The RF amplitude is determined to be r.m.s wise matched. The bucket height of the single harmonic system is too small even for shorter bunch with only 20% increased energy spread. The Halo formation and even debunching can be seen after a few synchrotron periods for single particles with large amplitude. In the case of small energy spread for a cooled beam, Coulomb interaction cannot be ignored. The external voltage has to be increased to keep the r.m.s bunch length unchanged. The new voltage ratio R(N) simplifies physics for the emittance-dominated bunches with modest particle number N. For the single harmonic system, substantial amount of debunching occurs without increasing the external voltage, but very little if the RF amplitude is doubled. Results from the ORBIT tracking code are presented for the 1 GeV bunch in the HESR synchrotron, part of the GSI FAIR project.  相似文献   

12.
A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.  相似文献   

13.
M. V. Lomonosov Moscow State University, Leninskie Gory, 119899, Moscow, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 2, pp. 38–46, March–April, 1995.  相似文献   

14.
Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·104 Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.  相似文献   

15.
Microphone array-based speech enhancement has great importance for speech communications and speech recognition. To reduce the aperture of the microphone array and to increase the effect of the speech enhancement will greatly broaden the application areas of the microphone array. An array crosstalk resistant adaptive noise cancellation method is therefore presented. And then an improved spectral subtraction algorithm is further cascaded to obtain better enhancement results. Theoretic analysis and experiments indicate that the proposed scheme needs only a very small microphone array while it simultaneously achieves a higher SNR improvement. Besides, the proposed scheme can be used in many noisy environments and is easy for real-time implementation.  相似文献   

16.
17.
Huaibei Environmental Monitoring Center, Huaibei, Anhui Province, 235000, P. R. China. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 6, pp. 76–80, November–December, 1995.  相似文献   

18.
Sap is transported under tension (i.e. negative pressure) in trees, according to the tension-cohesion theory. Since water is physically instable under negative pressure, a risk of cavitation is possible. Techniques have been developed during the past two decennia to study cavitation in trees. Trees appear remarkably immune to cavitation events. Cavities form only when extreme water stresses occur or when sap freezes. Nucleation is heterogeneous in trees, presumably caused by the aspiration of air bubbles through conduit walls. Threshold xylem pressures for cavitation vary greatly between species, in concordance with the great functional and ecological diversity of trees. To cite this article: H. Cochard, C. R. Physique 7 (2006).  相似文献   

19.
Gray cross correlation matching technique is adopted to extract candidate matches with gray cross correla- tion coefficients less than some certain range of maximal correlation coefficient called multi-peak candidate matches. Multi-peak candidates are extracted corresponding to three closest feature points at first. The corresponding multi-peak candidate matches are used to construct the model polygon. Correspondence is determined based on the local geometric relations between the three feature points and the multi-peak candidates. The disparity test and the global consistency checkout are applied to eliminate the remaining ambiguous matches that are not removed by the local geometric relational test. Experimental results show that the proposed algorithm is feasible and accurate.  相似文献   

20.
A study of the dynamical fluctuation properties at various c.m. Energies in e+e- collisions is performed using the Monte Carlo method. The results suggest that, after the normalized factorial moments of 3-dimensional phase space are analyzed using an isotropical phase space partition, the NFM describing non-linear dynamical properties show a power-law scaling, I.e., the dynamical fluctuations in higher dimensional phase space are isotropic. For c.m. Energies √s≤80 GeV,the scaling exponents φq increase rapidly with the c.m. Energy and for c.m. Energies √s>80 GeV,the φq gradually saturate.  相似文献   

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