1,017 research outputs found
Stochastic resonance with different periodic forces in overdamped two coupled anharmonic oscillators
We study the stochastic resonance phenomenon in the overdamped two coupled
anharmonic oscillators with Gaussian noise and driven by different external
periodic forces. We consider (i) sine, (ii) square, (iii) symmetric saw-tooth,
(iv) asymmetric saw-tooth, (v) modulus of sine and (vi) rectified sinusoidal
forces. The external periodic forces and Gaussian noise term are added to one
of the two state variables of the system. The effect of each force is studied
separately. In the absence of noise term, when the amplitude of the applied
periodic force is varied cross-well motion is realized above a critical value
() of . This is found for all the forces except the modulus
of sine and rectified sinusoidal forces.Stochastic resonance is observed in the
presence of noise and periodic forces. The effect of different forces is
compared. The logarithmic plot of mean residence time
against where is the intensity of the noise and
is the value of at which cross-well motion is initiated
shows a sharp knee-like structure for all the forces. Signal-to-noise ratio is
found to be maximum at the noise intensity at which mean
residence time is half of the period of the driving force for the forces such
as sine, square, symmetric saw-tooth and asymmetric saw-tooth waves. With
modulus of sine wave and rectified sine wave, the peaks at a value of
for which sum of in two wells of the potential of the system is
half of the period of the driving force. For the chosen values of and
, signal-to-noise ratio is found to be maximum for square wave while it
is minimum for modulus of sine and rectified sinusoidal waves.Comment: 13 figures,27 page
Experimental confirmation of chaotic phase synchronization in coupled time-delayed electronic circuits
We report the first experimental demonstration of chaotic phase
synchronization (CPS) in unidirectionally coupled time-delay systems using
electronic circuits. We have also implemented experimentally an efficient
methodology for characterizing CPS, namely the localized sets. Snapshots of the
evolution of coupled systems and the sets as observed from the oscilloscope
confirming CPS are shown experimentally. Numerical results from different
approaches, namely phase differences, localized sets, changes in the largest
Lyapunov exponents and the correlation of probability of recurrence
(), corroborate the experimental observations.Comment: Physical_Review_E_82_065201(R) 201
K-T impact(s): Continental, oceanic or both
Although geochemical and mineralogical evidence indicate that a major accretionary event occurred at the K-T boundary, no impact crater of suitable size and age was recognized. The 35 km Manson Structure, Iowa, was suggested recently as a possibility and Ar-40/Ar-39 determinations indicate that its formation age is indistinguishable from that of the K-T boundary. In order to test a possible association between Manson and the K-T boundary clay, the geochemistry and mineralogy of the K-T boundary clays at the Scollard Canyon section, Alberta and the Starkville South section, Colorado are compared with three dominant lithologies affected by the Manson impact: Proterozoic red clastics, underlying late-state granites, and gneisses. The chemical and mineralogical makeup of the Scollard Canyon boundary clay and its clastic constituents are presented, commenting on the implications for impact models. An impact into crystalline material of continental affinity appears to be required to explain the mineralogy and chemistry of the Scollard Canyon (and other Western N. American K-T sections). The low REE abundances of some K-T boundary layers are unusual but perhaps attempts should be made to understand the contributions of individual crustal components (e.g., carbonates, arkoses) as well as the potential for alteration involving these and other elements during and after impact-induced vaporization, before mantle excavation is invoked. If further studies confirm the results of published studies of marine boundary clays that indicate an oceanic target, attention must be paid to the possibility that multiple impacts occurred at the K-T boundary - one or more on the continents and one or more in the ocean
Numerical Simulation of Waves and Calculation of Hydrodynamic characteristics Over different seawalls
Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv
Flexible Emergent Vegetation in Staggered Configuration as Bioshields
Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv
Noise reduction in ECG signals for bio-telemetry
In Biotelemetry, Biomedical signal such as ECG is extremely important in the diagnosis of patients in remote location and is recorded commonly with noise. Considered attention is required for analysis of ECG signal to find the patho-physiology and status of patient. In this paper, LMS and RLS algorithm are implemented on adaptive FIR filter for reducing power line interference (50Hz) and (AWGN) noise on ECG signals .The ECG signals are randomly chosen from MIT_BIH data base and de-noising using algorithms. The peaks and heart rate of the ECG signal are estimated. The measurements are taken in terms of Signal Power, Noise Power and  Mean Square Error
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