We expand on prior results on noise supported signal propagation in arrays of
coupled bistable elements. We present and compare experimental and numerical
results for kink propagation under the ...influence of local and global
fluctuations. As demonstrated previously for local noise, an optimum range of
global noise power exists for which the medium acts as a reliable transmission
``channel''. We discuss implications for propagation failure in a model of
cardiac tissue and present a general theoretical framework based on discrete
kink statistics. Valid for generic bistable chains, the theory captures the
essential features ob served in our experiments and numerical simulations.
Noise-induced synchronized switching in coupled bistable systems Bulsara, A.R.; Inchiosa, M.E.; Lindner, J.F. ...
Proceedings 1995 Second New Zealand International Two-Stream Conference on Artificial Neural Networks and Expert Systems,
1995
Conference Proceeding
We consider a network of bistable dynamic elements with local, linear coupling, subject to noise and a time periodic signal. The response (quantified by an output signal to noise ratio, SNR) of a ...single element can be substantially enhanced when it is coupled into an array of like elements. In fact we show that noise and coupling cooperate to organize spatio temporal order across the array, corresponding to an increase in the output SNR of the reference element. The results shed new light on the potentially beneficial role of background noise in nonlinear dynamic devices and networks of neuron like elements.
The electrophysiological mechanisms underlying cardiac arrhythmias are studied by determining the spatiotemporal progression of cardiac depolarization and repolarization, termed cardiac mapping. ...Analysis of transient events requires information to be obtained from multiple sites simultaneously. The most significant problem with the design of such systems has been the large amount of data storage required and the rapidity of the composite data stream. Mapping systems with 500 simultaneous channels are common, and 4,000 channel systems have been envisioned. The authors report a relatively simple approach to this data storage problem that uses commercially available frame grabber technology coupled to a personal computer. With this approach they have developed a storage system capable of 24,000 channels sampled at 1 kHz with 12 bit resolution. Hybrid mapping systems incorporating optical recording systems utilizing voltage sensitive dyes from devices such as CCD cameras as well as conventional extracellular electrograms can simultaneously utilize this approach.
We expand on prior results on noise supported signal propagation in arrays of coupled bistable elements. We present and compare experimental and numerical results for kink propagation under the ...influence of local and global fluctuations. As demonstrated previously for local noise, an optimum range of global noise power exists for which the medium acts as a reliable transmission ``channel''. We discuss implications for propagation failure in a model of cardiac tissue and present a general theoretical framework based on discrete kink statistics. Valid for generic bistable chains, the theory captures the essential features ob served in our experiments and numerical simulations.
Chaotic dynamics have been successfully exploited in feedback control strategies. Recently, the authors have described the existence of unstable fixed points during ventricular fibrillation (VF), ...similar to those previously used in chaos control. Prior to embarking on control attempts of VF, a signal source was designed with known nonlinearly deterministic dynamics with well characterized stable and unstable manifolds as well as fixed point location. This ensured that the complex real-time data acquisition/analysis necessary to attempt such control was feasible for the interval durations typical of VF. A signal source was designed that can operate on any IBM compatible PC via the parallel port, and generates a waveform whose inter-event interval is nonlinearly deterministic with timing resolution of 0.1 /spl mu/sec with a range from 20 msec to 1.5 sec, independent of PC clock speed.
Technical Impracticability Bruckner, Amy E.; dePersia, Lee R.; Ditto, Arthur L.
The Military engineer,
10/1997, Letnik:
89, Številka:
587
Magazine Article
