4,252 research outputs found
Secure Communication using Compound Signal from Generalized Synchronizable Chaotic Systems
By considering generalized synchronizable chaotic systems, the
drive-auxiliary system variables are combined suitably using encryption key
functions to obtain a compound chaotic signal. An appropriate feedback loop is
constructed in the response-auxiliary system to achieve synchronization among
the variables of the drive-auxiliary and response-auxiliary systems. We apply
this approach to transmit analog and digital information signals in which the
quality of the recovered signal is higher and the encoding is more secure.Comment: 7 pages (7 figures) RevTeX, Please e-mail Lakshmanan for figures,
submitted to Phys. Lett. A (E-mail: [email protected]
Rich Variety of Bifurcations and Chaos in a Variant of Murali-Lakshmanan-Chua Circuit
A very simple nonlinear parallel nonautonomous LCR circuit with Chua's diode
as its only nonlinear element, exhibiting a rich variety of dynamical features,
is proposed as a variant of the simplest nonlinear nonautonomous circuit
introduced by Murali, Lakshmanan and Chua(MLC). By constructing a two-parameter
phase diagram in the plane, corresponding to the forcing amplitude
(F) and frequency , we identify, besides the familiar period-doubling
scenario to chaos, intermittent and quasiperiodic routes to chaos as well as
period-adding sequences, Farey sequences, and so on. The chaotic dynamics is
verified by both experimental as well as computer simulation studies including
PSPICE.Comment: 4 pages, RevTeX 4, 5 EPS figure
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
Markov Chain Monte Carlo: Can We Trust the Third Significant Figure?
Current reporting of results based on Markov chain Monte Carlo computations
could be improved. In particular, a measure of the accuracy of the resulting
estimates is rarely reported. Thus we have little ability to objectively assess
the quality of the reported estimates. We address this issue in that we discuss
why Monte Carlo standard errors are important, how they can be easily
calculated in Markov chain Monte Carlo and how they can be used to decide when
to stop the simulation. We compare their use to a popular alternative in the
context of two examples.Comment: Published in at http://dx.doi.org/10.1214/08-STS257 the Statistical
Science (http://www.imstat.org/sts/) by the Institute of Mathematical
Statistics (http://www.imstat.org
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