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The output characteristics of a linear monostable system driven with a periodic signal and an additive white Gaussian noise are studied in this paper. Theoretical analysis shows that the output signal-to-noise ratio (SNR) decreases monotonously with the increasing noise intensity but the output SNR-gain is stable. Inspired by this high SNR-gain phenomenon, this paper applies the linear monostable system in the parameters estimation algorithm for phase shift keying (PSK) signals and improves the estimation performance.

We examine the possibility of obtaining Set–Reset latch logical operation in a symmetric bistable system subjected to OU noise. Three major results are presented. First, we prove the Set–Reset latch logical operation can be obtained driven by OU noise. Second, while increasing the correlation time, the optimal noise band shifts to higher level and becomes wider. Meanwhile, peak performance degrades from 100% accuracy, but the system can still perform reliable logical operation. Third, at fixed noise intensity, the success probability evolves non-monotonically as correlation time increases. The study might provide development of the new paradigm of memory device.

Article history: We study the spatial dynamics of spiral waves in noisy Hodgkin-Huxley neuronal ensembles evoked by different information transmission delays and network topologies. In classical settings of coherence resonance the intensity of noise is fine-tuned so as to optimize the system's response. Here, we keep the noise intensity constant, and instead, vary the length of information transmission delay amongst coupled neurons. We show that there exists an intermediate transmission delay by which the spiral waves are optimally ordered, hence indicating the existence of delay-enhanced coherence of spatial dynamics in the examined system. Additionally, we examine the robustness of this phenomenon as the diffusive interaction topology changes towards the small-world type, and discover that shortcut links amongst distant neurons hinder the emergence of coherent spiral waves irrespective of transmission delay length. Presented results thus provide insights that could facilitate the understanding of information transmission delay on realistic neuronal networks. © 2008 Elsevier B.V. All rights reserved.

We study the transient properties of the laser phase in presence of the noise-correlation identified in a recent work (Phys. Lett. A 260 (1999) 126). Numerical results of the mean first-passage time (MFPT) T of laser phase are obtained for a range of value of the noise intensity Q and for various values of the correlation strength λ . The main features of the MFPT of laser phase are the following. In the positive correlation region, 0 λ T – Q curves can be classified into four categories: They are curves that possess zero, one, two, and four extrema, respectively. In the negative correlation region, −1 λ T – Q dependence has two types. For λ =−0.1 to 0, T decreases monotonously with increasing Q . In the region λ =−0.2 to −1, the T – Q curve has a maximum.

An exact analytical expression for the information transmitted through an array of threshold elements subject to a uniformly distributed signal and internal noise is presented. Additionally, approximations that accurately predict the optimal noise intensity and information gains achieved by the recently reported effect of suprathreshold stochastic resonance (N.G. Stocks, Phys. Rev. Lett. 84 (2000) 2310) are obtained.

Stochastic Resonance in a coupled FitzHugh-Nagumo equation is investigated. The optimal noise intensity and the optimal input frequency, which maximize the signal to noise ratio of the output signal, are studied numerically, and their dependence on system parameters and connection coefficients is examined. It is found that a network composed of six elements can separate a superimposed periodic pulse train by controlling the noise intensity.

Progress in the research in mechanical excess noise is reported. An improved technique for wire oscillation measurement has been applied to the investigation of the suspension of a test mass for a GW detector. The dependence of the excess noise intensity in the fundamental violin mode of the steel wires on the stress value is obtained.

We investigate the stochastic resonance in a FitzHugh-Nagumo neuronal model driven by colored noise with a 1 f β spectrum (0 ≤ β ≤ 2). A numerical simulation shows that the noise intensity needed to maximize the coherence between input and output signals is the smallest when β ≈ 1. We also demonstrate analytically that this phenomenon is never seen in a nondynamical threshold system.

All three essential ingredients (nonlinearity, periodic and random forces) are necessary for the onset of stochastic resonance. The mobility of an overdamped particle moving in a periodic potential and subject to a stochastic and a constant force (rather than a periodic one) remains a monotonic function of noise intensity in contrast to the results of Gang Hu [Phys. Lett. A 174 (1993) 247].

Experiments with molecular channels that form single microcontacts of 4 A in thin (50-60 A) dielectric films are presented. When a dielectric film separates 1 M aqueous potassium chloride solution, spectral measurements of noise in the steady microcontact do not reveal any 1/ƒ component. This makes it possible to estimate an upper limit for Hooge's empirical constant: α⩽10 -5 .