10 research outputs found
Parameter space of experimental chaotic circuits with high-precision control parameters
ACKNOWLEDGMENTS The authors thank Professor IberĂȘ Luiz Caldas for the suggestions and encouragement. The authors F.F.G.d.S., R.M.R., J.C.S., and H.A.A. acknowledge the Brazilian agency CNPq and state agencies FAPEMIG, FAPESP, and FAPESC, and M.S.B. also acknowledges the EPSRC Grant Ref. No. EP/I032606/1.Peer reviewedPublisher PD
Mutual information rate and bounds for it
The amount of information exchanged per unit of time between two nodes in a
dynamical network or between two data sets is a powerful concept for analysing
complex systems. This quantity, known as the mutual information rate (MIR), is
calculated from the mutual information, which is rigorously defined only for
random systems. Moreover, the definition of mutual information is based on
probabilities of significant events. This work offers a simple alternative way
to calculate the MIR in dynamical (deterministic) networks or between two data
sets (not fully deterministic), and to calculate its upper and lower bounds
without having to calculate probabilities, but rather in terms of well known
and well defined quantities in dynamical systems. As possible applications of
our bounds, we study the relationship between synchronisation and the exchange
of information in a system of two coupled maps and in experimental networks of
coupled oscillators
Black filled circles represent a Chuaâs circuit and the numbers identify each circuit in the networks.
<p>Coupling is diffusive. We consider 4 topologies: 2 coupled Chuaâs circuit (A), an array of 3 coupled circuits, an array of 4 coupled circuits, and a ring formed by 4 coupled circuits.</p
Magnetic properties of MnP nanowhiskers grown by MBE
Abstract MnP nanowhiskers have been grown by molecular-beam epitaxy technique on the InP(100) surface. The measurements of the magnetization revealed that samples with MnP nanowhiskers exhibit ferromagnetic behavior up to room temperature. The investigation of temperature and angular dependences of ferromagnetic resonance has shown the existence of 90 degree anisotropy. The high values of coercive field and peak temperature obtained for the samples make it possible to consider such materials for potential applications in spintronic devices
This picture is a hand-made illustration.
<p>Squares are filled as to create an image of a stochastic process whose points spread according to the given Lyapunov exponents. (A) A small box representing a set of initial conditions. After one iteration of the system, the points that leave the initial box in (A) go to 4 boxes along the diagonal line [filled squares in (B)] and 8 boxes off-diagonal (along the transverse direction) [filled circles in (B)]. At the second iteration, the points occupy other neighbouring boxes as illustrated in (C) and after an interval of time the points do not spread any longer (D).</p
Results for experimental networks of Double-Scroll circuits.
<p>On the left-side upper corner pictograms represent how the circuits (filled circles) are bidirectionally coupled. as (green online) filled circles, as the (red online) thick line, and as the (blue online) squares, for a varying coupling resistance . The unit of these quantities shown in these figures is (kbits/s). (A) Topology I, (B) Topology II, (C) Topology III, and (D) Topology IV. In all figures, increases smoothly from 1.25 to 1.95 as varies from 0.1k to 5k. The line on the top of the figure represents the interval of resistance values responsible to induce almost synchronisation (AS) and phase synchronisation (PS).</p
Results for two coupled maps. [Eq. (3)] as (green online) filled circles, [Eq. (5)] as the (red online) thick line, and [Eq. (7)] as the (blue online) crosses.
<p>In (A) and in (B) . The units of , , and are [bits/iteration].</p