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The processes of synchronization and phase cluster formation are investigated in a complex network of dynamically coupled phase oscillators. Coupling weights evolve dynamically depending on the phase relations between the oscillators. It is shown that the network exhibits several types of behavior: the globally synchronized state, two-cluster and multi-cluster states, different synchronous states with a fixed phase relationship between the oscillators and chaotic desynchronized state. [ABSTRACT FROM AUTHOR]

Frequency multiplicity is commonly found in time-delay coupled oscillator systems. But such frequencies could wreck the coherence of oscillators in the presence of noise. Here we propose a mechanism that would eliminate the frequency multiplicity. Time delay between coupled oscillators may affect the strength of the coupling itself. When this dependence on delay is cast as an exponential function, we show that multiplicity of phase-locked states might disappear leaving only a single oscillating frequency which is near the intrinsic oscillation frequency of the uncoupled oscillators. Such states could be either in-phase or anti-phase depending on the level of the intrinsic frequency or time delay. The in-phase locked state offers a robust mechanism of synchronizing delay-coupled oscillators without phase difference near their natural frequencies. [ABSTRACT FROM AUTHOR]

The TCP global synchronization problem is a phenomenon that packet losses or window control actions of different flows are synchronized. It causes degradation of the utilization of network bandwidth. RED is a well known approach to avoid this problem. However, discard of packets occurs in some probability even if they are in low-rate flow, and it might be unfair. In this paper, we propose new transmission rate control by using chaotic nature appearing in coupled oscillators. Our control can avoid the synchronization problem despite no use of random numbers and improve the network utilization. [ABSTRACT FROM PUBLISHER]

In this paper, we study the influence of switching couplings in synchronization of a random network of Kuramoto oscillators. The topology of the network is assumed to be time-varying and switched over time. In order to adjust the accuracy of the switching effect, we introduce a switching regulatory index which is combined with the local order parameter in each time interval to regulate the value of switching interval. Under this switching scheme, the network topology can be intermittently changed. Numerical simulations illustrate that phase synchronizability of Kuramoto oscillators can significantly be enhanced in Erdős-Rǩnyi network topology and scale-free network topology, but only slightly enhanced in small-world network topology under the proposed scheme. [ABSTRACT FROM PUBLISHER]

We propose a consensus-based algorithm for the synchronization of carrier signals in a wireless network. This work is motivated by recent progress on distributed beamforming and other cooperative MIMO techniques that require synchronized RF signals among all the cooperating nodes in a network and is aimed at addressing the limitations of the centralized master-slave approach used in previous work in this area. Our proposed algorithm is based on a variation of the classic Kuramoto model for the synchronization of coupled oscillators and is well-suited for a digital baseband implementation. We describe our proposed algorithm in detail and present initial results that show that this algorithm achieves global frequency lock given only that the network is connected i.e. there exists (possibly multi-hop) paths for every node to transmit and receive a signal from every other node. [ABSTRACT FROM PUBLISHER]

Common greenhouse gas molecu les SF6, NO2, CH4, and CO2 are modeled as harmonic oscillators whose potential and kinetic energies are derived. Using the Euler-Lagrange equation, their equations of motion are derived and their phase portraits are plotted. The authors use these data to attempt to explain the lifespan of these gases in the atmosphere. [ABSTRACT FROM AUTHOR]

We present a Bayesian framework for parameter inference in noisy, non-stationary, nonlinear, dynamical systems. The technique is implemented in two distinct ways: (i) Lightweight implementation to be used for on-line analysis, allowing multiple parameter estimation, optimal compensation for dynamical noise, and reconstruction by integration of the hidden dynamical variables, but with some limitations on how the noise appears in the dynamics; (ii) Full scale implementation of the technique with extensive numerical simulations (MCMC), allowing for more sophisticated reconstruction of hidden dynamical trajectories and dealing better with sources of noise external to the dynamics (measurements noise). [ABSTRACT FROM AUTHOR]

The problem of aging in a large population of coupled oscillators has been put forth recently, which means to study how its behavior changes by increasing the ratio of inactivated elements, i.e. damped oscillators. So far a number of interesting results such as aging transition have been found for some idealized systems chosen as a first step. Here we briefly describe our recent results about more general systems which have either nonscalar diffusive coupling or frequency distribution. [ABSTRACT FROM AUTHOR]

Coupled nonlinear oscillators operating in the presence of noise are widespread in nature. Examples include brain waves and cardiovascular oscillations. They can be amplitude or frequency-coupled, and are characterised by time-varying frequencies of oscillation. The time series related to cardiovascular and brain oscillations have been extensively analysed in the past decades and often associated with 1/f spectra. Their origin has been characterised variously as noise, chaotic dynamics and phase coupled oscillations. Here we present and discuss an unsolved problem of how to define and calculate instantaneous phases and frequencies of noisy coupled oscillators. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Most real-world networks display not only a heterogeneous distribution of degrees, but also a heterogeneous distribution of weights in the strengths of the connections. Each of these heterogeneities alone has been shown to suppress synchronization in random networks of dynamical systems. Here we review our recent findings that complete synchronization is significantly enhanced and becomes independent of both distributions when the distribution of weights is suitably combined with the distribution of degrees. We also present new results addressing the optimality of our findings and extending our analysis to phase synchronization in networks of non-identical dynamical unities. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]