共查询到20条相似文献,搜索用时 15 毫秒
1.
In this paper, stochastic behavior of FitzHugh–Nagumo neural system with two different kinds of time delays driven by colored noises is investigated. Based on the extended unified colored noise theory and the method of the probability density approximation, the Fokker–Planck equation and the steady-state probability density function are derived. Then through the two-state theory, the analytical expression of the signal-to-noise ratio (SNR) is also obtained. Finally, the effects of time delays and noise auto-correlation times in nonlinear dynamical system on the stationary probability density and the SNR are discussed respectively. 相似文献
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噪音关联对单模激光光强定态几率分布的影响 总被引:1,自引:1,他引:0
从理论上对加性白噪音和乘性色噪音之间存在关联作用的单模激光立方模型进行了分析.通过数值计算得到;噪音关联时间和噪音关联强度参量对光强定态几率分布曲线有很大影响;特别地,当两噪音之间存在完全负关联时,光强被锁定在某一固定值处. 相似文献
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Bei Xi Yong-Feng Guo Ya-Jun Shen Jian-Guo Tan Ming Liu 《Chinese Journal of Physics (Taipei)》2017,55(1):1-9
We study the transition problems in a piecewise nonlinear model induced by correlated multiplicative non-Gaussian noise and additive Gaussian white noise. Firstly, applying the path integral approach, the unified colored noise approximation, the analytical expression of the steady-state probability density function (SPD) is derived. Then the change regulation of the SPD is analyzed with the change of the strength and relevance of multiplicative noise and additive noise. From numerical computations we obtain some new nonlinear phenomena: the transition can be induced by the cross-correlation strength between noises, the non-Gaussian noise intensity and the Gaussian noise intensity as well as the non-Gaussian noise deviation parameter. This indicates that the effect of the non-Gaussian noise intensity on SPD is the same as that of the Gaussian noise intensity. Moreover, we also find the correlation time of the non-Gaussian noise can not induce the transition. 相似文献
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Fu HX Cao L Wu DJ 《Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics》1999,59(6):R6235-R6238
We study the thermal activation problem of a bistable system driven by correlated additive and multiplicative noises by means of numerical simulation. We find that in the colored noise case the suppression effect of the positive correlation decreases and finally is released as the autocorrelation time tau of the colored noise grows. When tau is large enough, negative correlation becomes more suppressive than the positive correlation. Such phenomena are ascribed to the collaboration between noises as well as the memory effect of the multiplicative colored noise. 相似文献
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本文主要研究了关联乘性非高斯噪声和加性高斯白噪声共同激励的FHN(Fitz Hugh-Nagumo)神经元系统.利用路径积分法和统一色噪声近似,推导出该系统的定态概率密度函数表达式.通过研究发现,乘性噪声强度D、加性噪声强度Q、噪声自关联时间τ以及互关联系数λ均可以诱导系统产生非平衡相变现象,而非高斯参数q却不可以诱导系统产生非平衡相变现象.此外,我们还发现参数D和λ的增大有利于神经元系统从激发态向静息态转换,Q和τ的增大有利于神经元系统从静息态向激发态转换,q的增大会使得神经元系统停留在静息态的概率增加. 相似文献
7.
S. Majhi B.K. Bera S. Banerjee D. Ghosh 《The European physical journal. Special topics》2016,225(1):65-74
We study the constructive role of noises in a Lorenz system with functional delay. The effect of delay can change the dynamics of the system to a chaotic one from its steady state. Induced synchronization with white and colored (red and green) noises are observed between two identical uncoupled systems and enhancement of synchrony is also observed with unidirectional coupling. We investigate both the phenomena in a globally coupled network in the presence of white and color noises. 相似文献
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在林木生长Logistic模型中, 引入加性和乘性关联色噪声, 运用统一色噪声近似、刘维方程以及诺维科夫原理, 推导了近似福克-普朗克方程, 分析了相关参数对稳态概率分布函数的影响. 结果表明: 改变乘性色噪声强度D和加性色噪声强度Q均能导致稳态概率分布曲线峰值高度的改变以及峰位置的移动, 对概率密度分布呈现出漂移作用. 但是在D和Q增大的过程中, 稳态概率分布曲线峰位置的移动方向是不同的: D增大时, 峰的位置向左移动; Q增大时, 峰的位置向右移动. 另外, 当λ >0时, 随着|λ|的增大, 稳态概率分布函数峰的位置向右移动, 且峰值的高度变大; 而λ<0时, 随着|λ|的增大, 稳态概率分布函数峰值的高度也变大, 而峰的位置却向左移动.
关键词:
林木生长
Logistic模型
色噪声
稳态概率分布 相似文献
10.
采用线性化近似,计算了由具有色关联的受偏置信号调制的色泵噪声和色量子噪声驱动 的单模激光增益模型的光强相对涨落,发现相对涨落随噪声强度的变化曲线中存在极小值,分析了偏置信号的强度、周期信号频率、噪声间的互关联强度和互关联时间对曲线的影响; 对单模激光增益模型在偏置信号调制和直接信号调制两种方式下的输出光强相对涨落进行了比较,发现光强涨落与偏置信号的强度密切相关.
关键词:
偏置信号调制
光强相对涨落
线性化近似 相似文献
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In this paper, we introduce a noise which is composed of multiplication of two dichotomous noises, and derive the probability density and the statistical properties of this noise. The obtained results can help study the resonant activation phenomenon, the phenomenon of stochastic resonance, the transport of particles, and the nonequilibrium (phase) transition for the systems driven by this noise. 相似文献
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We study Brownian motors driven by colored non Gaussian noises, both in the overdamped regime and in the case with inertia, and analyze how the departure of the noise distribution from Gaussian behavior can affect its behavior. We analyze the problem from two alternative points of view: one oriented mainly to possible technological applications and the other more inspired in natural systems. In both cases we find an enhancement of current and efficiency due to the non-Gaussian character of the noise. We also discuss the possibility of observing an enhancement of the mass separation capability of the system when non-Gaussian noises are considered.Received: 8 July 2004, Published online: 30 September 2004PACS:
05.45.-a Nonlinear dynamics and nonlinear dynamical systems - 05.40.Jc Brownian motion - 87.16.Uv Active transport processes; ion channels 相似文献
15.
Feng-guo Li 《Central European Journal of Physics》2008,6(3):539-545
Noise can induce an inverse period-doubling transition and chaos. The effects of noise on each periodic orbit of three different
period sequences are investigated for the logistic map. It is found that the dynamical behavior of each orbit, induced by
an uncorrelated Gaussian white noise, is different in the mergence transition. For an orbit of the period-six sequence, the
maximum of the probability density in the presence of noise is greater than that in the absence of noise. It is also found
that, under the same intensity of noise, the effects of uncorrelated Gaussian white noise and exponentially correlated colored
(Gaussian) noise on the period-four sequence are different.
相似文献
16.
The underdamped Josephson junction subjected to correlated colored noises was investigated. The results indicated that: (i) There
are two critical phenomena in the system; (ii) Net voltage of the system is induced by multiplicative noise, and exhibits
non-monotonic behaviors with noise autocorrelation rate and the Josephson junction capacitance. 相似文献
17.
在Levins模型的基础上研究了色交叉关联噪声对集合种群稳定性的影响, 应用Fokker-Plank方程得到了系统的稳态概率密度函数, 运用最快下降法得到了平均灭绝时间的解析式. 结果表明: 两噪声色关联时, 加性噪声强度和乘性噪声强度均弱化集合种群的稳定性; 噪声关联强度强化集合种群的稳定性. 两噪声之间负关联时, 平均灭绝时间是加性噪声强度和乘性噪声强度的减函数, 是噪声关联时间的增函数; 两噪声之间正关联时, 平均灭绝时间是加性噪声强度和噪声关联时间乘性噪声强度的减函数, 是乘性噪声强度的非单调函数.
关键词:
集合种群
色交叉关联噪声
稳定性
平均灭绝时间 相似文献
18.
S. E. Mangioni H. S. Wio 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,61(1):67-73
We analyze the effect of a colored non Gaussian noise on a model of
a random walker moving along a ratchet potential. Such a model was
motivated by the transport properties of motor proteins, like
kinesin and myosin. Previous studies have been realized assuming
white noises. However, for real situations, in general we could
expect that those noises be correlated and non Gaussian. Among other
aspects, in addition to a maximum in the current as the noise
intensity is varied, we have also found another optimal value of the
current when departing from Gaussian behavior. We show the relevant
effects that arise when departing from Gaussian behavior,
particularly related to current's enhancement, and discuss its
relevance for both biological and technological situations. 相似文献
19.
《中国物理快报》2017,(7)
We discuss the dynamical behavior of a chemical network arising from the coupling of two Brusselators established by the relationship between products and substrates. Our interest is to investigate the coherence resonance(CR)phenomena caused by noise for a coupled Brusselator model in the vicinity of the Hopf bifurcation, which can be determined by the signal-to-noise ratio(SNR). The CR in two coupled Brusselators will be considered in the presence of the Gaussian colored noise and two uncorrelated Gaussian white noises. Simulation results show that,for the case of single noise, the SNR characterizing the degree of temporal regularity of coupled model reaches a maximum value at some optimal noise levels, and the noise intensity can enhance the CR phenomena of both subsystems with a similar trend but in different resonance degrees. Meanwhile, effects of noise intensities on CR of the second subsystem are opposite for the systems under two uncorrelated Gaussian white noises. Moreover,we find that CR might be a general phenomenon in coupled systems. 相似文献
20.
HAN Li-Bo CAO Li WU Da-Jin WANG Jun 《理论物理通讯》2004,42(7)
By using the linear approximation method, the intensity correlation function and the intensity correlation time are calculated in a gain-noise model of a single-mode laser driven by colored cross-correlated pump noise and quantum noise, each of which is colored. We detect that, when the cross-correlation between both noises is negative, the behavior of the intensity correlation function C(t) versus time t, in addition to decreasing monotonously, also exhibits several other cases, such as one maximum, one minimum, and two extrema (one maximum and one minimum), i.e., some parameters of the noises can greatly change the dependence of the intensity correlation function upon time. T3. 相似文献