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Jitter noise reduction can be achieved by controlling the position of magnetic grains, but write synchronization is needed to take advantage of the potential reduction. A periodic read-back response can be obtained from DC-erased bits, which is composed of rows of grains. In this paper, the feasibility of creating a clock signal for write synchronization using this periodicity of the readback response is investigated. As a result, it was confirmed that a clock signal can be created by using the precise periodicity of the read-back response. [ABSTRACT FROM AUTHOR]

We study the problem of frame synchronization over a discrete memoryless channel (DMC) in an asynchronous setup. A sync frame is transmitted at a random time $V$ with a known distribution $\{a_{v} \}$ and entropy $H$. We seek to characterize the minimum average length or energy of the sync frame necessary for error-free frame synchronization, as $H$ tends to infinity. We present a variable length sync frame, where the length of the sync frame is adapted based on $H$ and $\{a_{v} \}$ , for the general arrival distribution and show error-free frame synchronization when the average sync frame length $\bar {N}$ scales as $\Omega (({H}/{\alpha (Q)})$ , where $\alpha (Q)$ is the synchronization threshold of the DMC. We then generalize the framework and study a tradeoff between $\bar {N}$ and $\alpha (Q)$ for optimal frame synchronization and characterize the scaling needed of both $\bar {N}$ and $\alpha (Q)$ with $H$. We illustrate our results with the AWGN channel and discuss the adapting sync frame length and symbol power for optimal frame synchronization. Finally, using numerical work and simulations, we evaluate the results under relaxed assumptions, including the imperfect knowledge of arrival distribution and symbol timing error. [ABSTRACT FROM AUTHOR]

We experimentally investigate the synchronization of driven metronomes using a servo motor to impose external control. We show that a driven metronome will only synchronize in a narrow range near its own frequency; when we introduce coupling between metronomes, we can widen the range of frequencies over which a metronome will synchronize to the external input. Using these features, we design a signal to synchronize a population of dissimilar metronomes; separately we design a signal to selectively synchronize a subpopulation of metronomes within a heterogeneous population. [ABSTRACT FROM AUTHOR]

This paper investigates an adaptive neural network prescribed performance synchronization scheme for unknown complex dynamic networks with different dimensions. Based on predefined performance bounded and Lyapunov stability theory, adaptive neural networks controllers are designed to ensure that synchronization errors remain in a neighborhood of origin with the prescribed bounds. In addition, the paper analyses in detail that the synchronization behaviors between drive network selected as the three-dimension chaotic system and response network selected as the four-dimension hyperchaotic chaotic system. The numerical simulation results are presented to show the validity of the proposed approach. [ABSTRACT FROM AUTHOR]

We propose an innovative method of automatic video summary generation with personal adaptations. User interests are mined from their personal image collections. To reduce the semantic gap, we propose to extract visual representations based on a novel semantic tree (SeTree). A SeTree is a hierarchy that captures the conceptual relationships between the visual scenes in a codebook. This idea builds upon the observation that such semantic connections among the elements have been overlooked in the previous work. To construct the SeTree, we adopt a normalized graph cut clustering algorithm by conjunctively exploiting visual features, textual information, and social user-image connections. Using this technique, we obtain an 8.1% improvement of normalized discounted cumulative gain in personalized video segments ranking compared with existing methods. Furthermore, to promote the interesting parts of a video, we extract a space–time saliency map and estimate the attractiveness of segments by kernel fitting and matching. A linear function is utilized to combine the two factors, based on which the playback rate of a video is adapted to generate the summary. We play the less important segments in a fast-forward mode to keep users updated with the context. Subjective experiments were conducted which showed that our proposed video summarization approach outperformed the state-of-the-art techniques by 6.2%. [ABSTRACT FROM PUBLISHER]

Two experiments were conducted to examine framing effects in sport. In Experiment 1, a conceptual replication [Loftus, E. F., & Palmer, J. C. (1974). Reconstruction of automobile destruction: An example of the interaction between language and memory.Journal of Verbal Learning and Verbal Behavior,13(5), 585–589], participants watched a hockey collision, with the hit described later in a written format as a “contact”, “bump”, or “smash”. This manipulation resulted in no differences in participants’ report of how fast the players were skating, their intentions, and the outcome of the hit. In Experiment 2, participants watched the same video clip with ongoing commentary. Those who heard the announcer describing the event as “contact” estimated a higher skating speed than participants who were exposed to the “smash” commentary. Participants who were exposed to the “bump” commentary rated the repercussions of the collision as less severe than did those exposed to the other commentaries. These findings show that the perception of magnitude hierarchy may be domain specific and suggest future avenues for exploring framing effects when one is exposed to visual stimuli. [ABSTRACT FROM PUBLISHER]

This paper investigates the synchronization problem of a class of general hybrid coupling delayed neural networks with internal delay as well as coupling delay. A general hybrid coupling term involving current-state coupling, discrete-delay coupling and distributed-delay coupling is considered. The partial mixed pinning impulsive control is proposed for achieving synchronization, which is combined with the advantage of pinning impulsive control and two impulsive effects simultaneously (i.e. synchronization and desynchronization). In order to handle the difficulties of multi-time delays, some generalized differential inequalities about time-varying delays are established. By using Lyapunov functional method and applying a mixed pinning impulsive control scheme, some sufficient conditions are derived to guarantee global synchronization of the neural networks. Moreover, our results can cover and extend the previous related works. Finally, numerical examples are also given to illustrate the efficiency of our methods and the theoretical results. [ABSTRACT FROM AUTHOR]

This paper investigates the problem of fault-tolerant synchronization control for complex dynamical networks with semi-Markov jump topology. The main purpose is to design a fault-tolerant controller so as to make the resultant closed-loop system is stochastically synchronous in the presence of actuator failures. Some sufficient conditions to ensure the presence of the controller are obtained by constructing a mode-dependent Lyapunov–Krasovskii functional and employing some novel inequalities. Based on these conditions, a clear expression for the desired controller is given by using a simple matrix decoupling method. Finally, a simulation example is given to demonstrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

A high precision multi-node clock network for multiple users was built following the precise frequency transmission and time synchronization of 120 km fiber. The network topology adopts a simple star-shaped network structure. The clock signal of a hydrogen maser (synchronized with UTC) was recovered from a 120 km telecommunication fiber link and then was distributed to 4 sub-stations. The fractional frequency instability of all substations is in the level of 10-15 in a second and the clock offset instability is in sub-ps in root-mean-square average. [ABSTRACT FROM AUTHOR]

This paper deals with fractional order Chua system with cubic nonlinearity (cubic Chua system), which is a modification of Chua system. The aim is, first, to study the chaotic behavior in fractional order cubic Chua system.We found that chaos indeed exists in the fractional version of this system. The necessary condition for exhibiting chaotic attractors similar to its integer order counterpart is presented. This condition is used to distinguish for which parameters and orders the system generates double scroll chaotic attractors. The synchronization problem between two coupled chaotic fractional order cubic Chua systems is then addressed. An adaptive feedback control scheme for the synchronization with suitable feedback nonlinear controller applied to the response system is presented. Numerical simulations are performed to verify the theoretical analysis. [ABSTRACT FROM AUTHOR]

Complex dynamical structures inherent in degenerate optical parametric oscillator (DOPO) system are studied in detail. The system under consideration is actually the temporal part of the original DOPO system. A host of fixed points and the corresponding route to chaos are analysed. In the process, several forms of attractors and bifurcation patterns are seen. The stability zones are enumerated with the help of the bi-parametric Lyapunov plots or shrimp structures. Lastly, we have analysed the behaviour of two such coupled systems for the analysis of different modes of synchronization. The coupling is chosen in different ways. One is the direct one, the other through quorum sensing and lastly through delayed quorum sensing. It is observed that introduction of delay effects the time to achieve synchronization. In each case, the stability and other properties are analysed. [ABSTRACT FROM AUTHOR]

We propose an approach for the synchronization of video streams using correntropy. Essentially, the time offset is calculated on the basis of the instantaneous transfer rates of the video streams that are extracted in the form of a univariate signal known as variable bit-rate (VBR). The state-of-the-art approach uses a window segmentation strategy that is based on consensual zero-mean normalized cross-correlation (ZNCC). This strategy has an elevated computational complexity, making its application to synchronizing online data streaming difficult. Hence, our proposal uses a different window strategy that, together with the correntropy function, allows the synchronization to be performed for online applications. This provides equivalent synchronization scores with a rapid offset determination as the streams come into the system. The efficiency of our approach has been verified through experiments that demonstrate its viability with values that are as precise as those obtained by ZNCC. The proposed approach scored 81% in time reference classification against the equivalent 81% of the state-of-the-art approach, requiring much less computational power. [ABSTRACT FROM AUTHOR]

In this paper, the emergence of hyperchaos in a network with two very simple discrete periodic oscillators is presented. Uncoupled periodic oscillators may represent, in the crudest and simplest form, periodic oscillators in nature, for example fireflies, crickets, menstrual cycles of women, among others. Nevertheless, the emergence of hyperchaos in this kind of real-life network has not been proven. In particular, we focus this study on the emergence of hyperchaotic dynamics, considering that these can be mainly used in engineering applications such as cryptography, secure communications, biometric systems, telemedicine, among others. In order to corroborate that the emerging dynamics are hyperchaotic, some chaos and hyperchaos verification tests are conducted. In addition, the presented hyperchaotic coupled systemsynchronizes, based on the proposed coupling scheme. [ABSTRACT FROM AUTHOR]

Phase synchronization may emerge from mutually interacting non-linear oscillators, even under weak coupling, when phase differences are bounded, while amplitudes remain uncorrelated. However, the detection of this phenomenon can be a challenging problem to tackle. In this work, we apply the Discrete Complex Wavelet Approach (DCWA) for phase assignment, considering signals from coupled chaotic systems and experimental data. The DCWA is based on the Dual-Tree Complex Wavelet Transform (DT-CWT), which is a discrete transformation. Due to its multi-scale properties in the context of phase characterization, it is possible to obtain very good results from scalar time series, even with non-phase-coherent chaotic systems without state space reconstruction or pre-processing. The method correctly predicts the phase synchronization for a chemical experiment with three locally coupled, non-phase-coherent chaotic processes. The impact of different time-scales is demonstrated on the synchronization process that outlines the advantages of DCWA for analysis of experimental data. [ABSTRACT FROM AUTHOR]

Synchronization of two exciters with asymmetric structure is more widely used in engineering, such as vibrating conveyer, dewatering screen, vibrating screen, however, the synchronization state of two exciters with asymmetric structure in the sub-resonant and super-resonant states is less considered, and it is a valuable research topic. Firstly, we establish a kind of weakly nonlinear vibrating system driven by two exciters with opposite rotation directions and asymmetrical structure. Using Lagrange equations, the differential equations of the vibrating system are obtained. Secondly, we apply Fourier series expansion to obtain the nonlinear elastic force of the nonlinear stiffness. Thirdly, we introduce the modified averaging method of small parameters and Hamilton's principle to get the criterions of synchronization synchronization stability of two exciters. The theoretical analysis shows that the phase differences are stabilized in the vicinity of Pi phase difference in a super-resonant state when le approaches to l0, otherwise, in the neighborhood of zero phase difference in a sub-resonant state. Then, the above theory is verified by experiments. The stable phase difference, amplitudes responses and energy consumption are also discussed. This research provides the foundation and guidance for the synchronization of two exciters with horizontal asymmetrical structure and engineering design. [ABSTRACT FROM AUTHOR]

This paper discusses the control of the linear switched reluctance machines (LSRMs) network for the zero phase-difference tracking to a sinusoidal reference. The dynamics of each LSRM is derived by online system identification and modeled as a second-order linear system. Accordingly, based on the coupled harmonic oscillators synchronization manner, a distributed control strategy is proposed to synchronize each LSRMstate to a virtual LSRMnode representing the external sinusoidal reference for tracking it with zero phase-difference. Subsequently, a simulation scenario and an experimental platform with the identical parameter setup are designed to investigate the tracking performance of the LSRMs network constructed by the proposed distributed control strategy. Finally, the simulation and experimental results verify the effectiveness of the proposed LSRMs network controller, and also prove that the coupled harmonic oscillators synchronization method can improve the synchronization tracking performance and precision. [ABSTRACT FROM AUTHOR]

This paper deals with the stochastic exponential synchronization problem of memristor-based neural networks with time-varying delay. Firstly, considering the state-dependent properties of the memristor, less conservative of model is constructed to analyze the complicated memristor-based neural networks. Then, by applying the stochastic differential inclusions theory and Lyapunov functional approach, sufficient verifiable conditions that depend on the time-varying delay and stochastic perturbation are obtained. It is shown that synchronization can be realized by linear feedback control and adaptive feedback control. The derived results complement and improve the previously known results. Finally, a numerical example is given to illustrate the effectiveness of the theoretical results. [ABSTRACT FROM AUTHOR]

Based on function projective synchronization theorem, a novel type of synchronization scheme called generalized binary function projective synchronization is proposed. Combining adaptive control theory with special matrix structure, an extended adaptive controller which is more general than some existing controllers is designed. Under the controller, the proposed synchronization between two different uncertain chaotic systems is achieved and the unknown parameters are also estimated. Numerical simulation result is presented to show the validity and feasibility of the scheme and controller. [ABSTRACT FROM AUTHOR]

Maximum likelihood estimation problems are, in general, intractable optimization problems. As a result, it is common to approximate the maximum likelihood estimator (MLE) using convex relaxations. In some cases, the relaxation is tight: it recovers the true MLE. Most tightness proofs only apply to situations where the MLE exactly recovers a planted solution (known to the analyst). It is then sufficient to establish that the optimality conditions hold at the planted signal. In this paper, we study an estimation problem (angular synchronization) for which the MLE is not a simple function of the planted solution, yet for which the convex relaxation is tight. To establish tightness in this context, the proof is less direct because the point at which to verify optimality conditions is not known explicitly. Angular synchronization consists in estimating a collection of n phases, given noisy measurements of the pairwise relative phases. The MLE for angular synchronization is the solution of a (hard) non-bipartite Grothendieck problem over the complex numbers. We consider a stochastic model for the data: a planted signal (that is, a ground truth set of phases) is corrupted with non-adversarial random noise. Even though the MLE does not coincide with the planted signal, we show that the classical semidefinite relaxation for it is tight, with high probability. This holds even for high levels of noise. [ABSTRACT FROM AUTHOR]

In this paper, we study the influence of the inertial effect on frequency synchronization in an ensemble of Kuramoto oscillators with finite inertia and symmetric and connected interactions. We present sufficient conditions in terms of coupling strength, algebraic connectivity, natural frequencies, and the inertial term to guarantee the occurrence of frequency synchronization. We also make a comparison with the existing conditions proposed for the first-order Kuramoto model and conclude that the inertial effect, if appropriately small, has little influence on frequency synchronization as long as the initial phase configurations are distributed in a half circle. [ABSTRACT FROM AUTHOR]

Ruminal synchronization of energy and protein supply is a strategy suggested by nutritionists to increase the efficiency of ruminant metabolic processes such as microbial protein synthesis and to decrease the environmental excretion of nutrients. A so-called synchronization index ( SI ), formulated as a function of the ratio of nitrogen to organic matter release in the rumen, is widely used to quantify and evaluate ruminal synchronization. A main concern is that SI values obtained from the in situ experimental method are influenced by many random factors and therefore SI value, calculated by the currently-used formula, may not represent actual degree of synchronization. Therefore, in this paper, we comprehensively examine sensitivity of SI to random variations (unwanted measurement errors) due to the experimental conditions variability. Evaluations were performed by means of in situ experiments on 3 ruminally fistulated Holstein lactating dairy cows, where 18 different diets were studied. The diets (g/kg DM) were formulated to a range of CP (150–190), NFC (300–400), NDF (310–410), and ADF (169–246). Based on measured data, a set of synthetic data were also generated to study a range of random variations and their effect on SI values. Our results indicated that SI values are quite sensitive to the random variations ( i.e. , significantly decrease as random variations increase). This fact revealed that the currently used SI depends not only on degree of synchronization, but also on degree of random variations due to the inevitable experimental conditions variability. Therefore, the original SI is not fully representative of the actual synchronization when having a high degree of variability. To resolve this problem, we propose a novel approach to calculating SI based on a regression analysis on measured data of nitrogen and organic matter release followed by an analytical derivation of SI based on the regression results. The SI values obtained from the new method showed minimal sensitivity to the random variations. The original method yielded a much lower SI than the new method (0.64 vs. 0.92) for our optimum diet (g/kg DM) (NFC = 350, NDF = 330, ADF = 183, and CP = 165), showing some degrees of asynchrony for this diet. Therefore, we conclude that the new method provides more reliable SI values for determining and quantifying ruminal synchronization. [ABSTRACT FROM AUTHOR]

This paper investigates the performance of acquisition section of synchronization in direct-sequence spread spectrum (DSSS-CDMA) under jamming attacks. DSSS-CDMA in this study uses chaotic sequences. The synchronization performance is analyzed under Gaussian and repeater jammer. The results of initial investigation show that the synchronization in DSSS-CDMA is vulnerable under these two jammers which may have significant effect on the probability of error rate. The analysis is performed based on the probability of detection and probability of false alarm, and mathematical expressions of these probabilities are derived. The amount of power which is required for each jammer to collapse the synchronization is derived. The theoretical results have been verified through Monte Carlo simulations in MATLAB. [ABSTRACT FROM AUTHOR]

We characterize the phase space for the infinite volume limit of a ferromagnetic mean-field XY model in a random field pointing in one direction with two symmetric values. We determine the stationary solutions and detect possible phase transitions in the interaction strength for fixed random field intensity. We show that at low temperature magnetic ordering appears perpendicularly to the field. The latter situation corresponds to a spin-flop transition. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the anti-synchronization between a class of chaotic real nonlinear systems and a class of chaotic complex nonlinear systems with fully uncertain parameters. According to Lyapunov stability theory, an adaptive control scheme and adaptive laws of parameters have been designed to realize the anti-synchronization between a class of chaotic real nonlinear systems and a class of chaotic complex nonlinear systems with different initial conditions. The anti-synchronization between the real Lorenz system and the complex Lorenz system, the real Chen system and the complex Lü system are presented as two examples to demonstrate the validity and feasibility of the presented control technique. [ABSTRACT FROM AUTHOR]

The mean square exponential (MSE) synchronization problem is investigated in this paper for complex networks with simultaneous presence of uncertain couplings and incomplete information, which comprise both the randomly occurring delay and the randomly occurring non-linearities. The network considered is uncertain with time-varying stochastic couplings. The randomly occurring delay and non-linearities are modelled by two Bernoulli-distributed white sequences with known probabilities to better describe realistic complex networks. By utilizing the coordinate transformation, the addressed complex network can be exponentially synchronized in the mean square if the MSE stability of a transformed subsystem can be assured. The stability problem is studied firstly for the transformed subsystem based on the Lyapunov functional method. Then, an easy-to-verify sufficient criterion is established by further decomposing the transformed system, which embodies the joint impacts of the single-node dynamics, the network topology and the statistical quantities of the uncertainties on the synchronization of the complex network. Numerical examples are exploited to illustrate the effectiveness of the proposed methods. [ABSTRACT FROM AUTHOR]

We derive a Hamiltonian version of the PT-symmetric discrete nonlinear Schrödinger equation that describes synchronized dynamics of coupled pendula driven by a periodic movement of their common strings. In the limit of weak coupling between the pendula, we classify the existence and spectral stability of breathers (time-periodic solutions localized in the lattice) supported near one pair of coupled pendula. Orbital stability or instability of breathers is proved in a subset of the existence region. [ABSTRACT FROM AUTHOR]

In this paper, the synchronization problem for a class of generalized neural networks with time-varying delays and reaction-diffusion terms is investigated concerning Neumann boundary conditions in terms of p-norm. The proposed generalized neural networks model includes reactiondiffusion local field neural networks and reaction-diffusion static neural networks as its special cases. By establishing a new inequality, some simple and useful conditions are obtained analytically to guarantee the global exponential synchronization of the addressed neural networks under the periodically intermittent control. According to the theoretical results, the influences of diffusion coefficients, diffusion space, and control rate on synchronization are analyzed. Finally, the feasibility and effectiveness of the proposed methods are shown by simulation examples, and by choosing different diffusion coefficients, diffusion spaces, and control rates, different controlled synchronization states can be obtained. [ABSTRACT FROM AUTHOR]

The objective of this letter is to convey two essential principles of biological computing—synchronization and memory—in an electronic circuit with two van der Pol (vdP) oscillators coupled via a memristive device. The coupling was mediated by connecting the gate terminals of two programmable unijunction transistors through a resistance-capacitance network comprising an Ag-TiOx-Al memristive device. In the high resistance state the memristance was in the order of MΩ, which leads to two independent self-sustained oscillators characterized by the different frequencies f1 and f2 and no phase relation between the oscillations. Depending on the mediated pulse amplitude, the memristive device switched to the low resistance state after a few cycles and a frequency adaptation and phase locking were observed. The experimental results are underlined by theoretically considering a system of two coupled vdP equations. This experiment may pave the way to larger neuromorphic networks in which the coupling parameters (through memristive devices) can vary in time and strength and are able to remember the history of applied electrical potentials. [ABSTRACT FROM AUTHOR]

We study the enhancement of neural synchrony in a network of electrically coupled Hindmarsh Rose (HR) neurons. The behavior of the network under control by an external environment modeled by the Fitzhugh Nagumo (FN) is analyzed. Biologically, such a control system could mimic the modification of normal neuronal dynamics due to drugs or other chemical substances. We show that the environment could have as effect the suppression of chaos, enhancement of synchrony and favor interesting properties such as sub-threshold membrane oscillations, and oscillation death for relatively strong local coupling. Interestingly, we find that the electrical coupling between each two coupled HR and FN is less important to synchronization than the local coupling between the HR and the FN neurons. In other words, local interactions are found to play a stronger role in synchronization than long-range (global) interactions. [ABSTRACT FROM AUTHOR]

Many studies on the switched modified function projective synchronization of nonlinear real dynamic systems have been carried out, whereas the switched modified function projective synchronization of chaotic complex systems has not been studied extensively. In this paper, the concept of the partial switched modified function projective synchronization of complex nonlinear systems with fully unknown parameters is proposed. Partial switched synchronization of chaotic systems means that the state variables of the drive system synchronize with partial different state variables of the response system. Based on the parameter modulation and the adaptive control technique, the adaptive control laws and the parameter update laws are derived to make the states of two different complex nonlinear systems asymptotically synchronized up to a desired scaling function matrix. The given scaling function can be an equilibrium point, a periodic orbit, or even a chaotic attractor in the phase space. Finally, numerical simulations are performed to verify the feasibility and effectiveness of the proposed controllers and identifiers. [ABSTRACT FROM AUTHOR]

In dissipationless linear lattices, spatial disorder or quasiperiodic modulations in on-site potentials induce localization of the eigenstates and block the spreading of wave packets. Quasiperiodic inhomogeneities allow for the metal-insulator transition at a finite modulation amplitude already in one dimension. We go beyond the dissipationless limit and consider nonlinear quasi-periodic arrays that are additionally subjected to dissipative losses and energy pumping. We find finite excitation thresholds for oscillatory phases in both metallic and insulating regimes. In contrast to disordered arrays, the transition in the metallic and weakly insulating regimes display features of the second order phase transition accompanied by a large-scale cluster synchronization. In the limit of strong localization, we find the existence of globally stable asymptotic states consisting of several localized modes. These localization attractors and chaotic synchronization effects can be potentially implemented with polariton condensate lattices and cavity-QED arrays. [ABSTRACT FROM AUTHOR]

Multicore instruction-set simulation (MCISS) has become more and more important due to tremendous increase in number of multicore designs. To boost the speed of MCISS, one of the most effective and commonly used approaches is parallel simulation. However, timing synchronization must be applied to ensure accurate simulation results of parallel MCISS, and may induce huge synchronization overhead. In this paper, we propose a highly efficient and effective parallel MCISS approach by synchronizing timing before each synchronization function (SF) call. We improve the applicability of the state-of-the-art critical-section-level simulation approach with a generic blocking/nonblocking send/receive model covering all types of SFs. To further reduce synchronization overhead, we also introduce optimization methods such as a hybrid scheduling technique and provide an analysis algorithm that helps the designers to choose the host platform with the best simulation performance. Experiments show that the proposed approach attains a simulation speed of up to 285 MIPS, while producing accurate timing and functional results. [ABSTRACT FROM AUTHOR]

Time synchronization is a fundamental requirement for many services provided by distributed systems. For this purpose, several time synchronization protocols have been proposed. However, they either achieve high accuracy by adding further network traffic, even more than common protocols such as network time protocol and precision time protocol, or consume a lot of time in additional computations. An online distributed tracing and monitoring system, used to identify functional and performance problems in distributed systems, must offer high precision with minimum time overhead and system resource consumption. The aim of this paper is to propose an efficient algorithm for time synchronization in online mode, applicable for all distributed services. The proposed method in this paper addresses five key requirements for a practical solution in distributed systems. First, it provides microseconds scale accuracy, which is applicable for trace events with nanosecond timestamp granularity. Secondly, it does not require adding new network traffic, using the send and receive time of existing traffic. Thirdly, it synchronizes the distributed traces in average time complexity of O(1) per synchronization update. Fourthly, it updates online synchronization parameters immediately without latency. Finally, it iteratively refines the early estimates without requiring significant buffering of earlier data. Although we used this work for distributed trace synchronization, it is a general, fully incremental, continuous synchronization approach applicable to most synchronization purposes. [ABSTRACT FROM AUTHOR]

With the rapid development of integrated circuit manufacturing processes, poor system scalability has become a prominent problem for System on Chip (SoC).To solve the bottleneck problems such as global synchronization, network on chip Networks on Chip (NoC) has emerged as a new design to tackle the increasing communication demand among elements on chips. With the development of networks-on-chip, the research has expanded from two-dimensional to three-dimensional design, and 3D networks-on-chip is a combination of 3D integration technology and 2D networks-on-chips with the advantages of both to meet the development trend of diversified chip functions. This paper presents an improved floorplanning optimization algorithm based on simulated annealing algorithm (Comprehensive Improved Simulated Annealing, hereinafter referred to as CISA algorithm) to replace the original floorplanning optimization algorithm based on simulated annealing algorithm (Simulated Annealing, hereinafter referred to as SA algorithm) to make it more applicable to the three-dimensional network-on- chip simulation. This paper describes the CISA algorithm improvement ideas and uses it on an existing 3D network-on-chip simulator with a set of classical simulation tests. The results show that the proposed CISA algorithm is better than the original SA algorithm and it is more suitable for simulations of three-dimensional networks-on-chip, especially when dealing with large scale 3D NoC. [ABSTRACT FROM AUTHOR]

Considering that time-delay is frequently encountered in a variety of practical chaotic systems, we investigate the complete synchronization (CS) of coupled multiple-time-delay complex chaotic systems and design the control law by error feedback, which is simple in principle and easy to implement in engineering. A communication scheme is further designed according to chaotic masking. We take coupled multiple-time-delay complex Lorenz system as an example, make simulations and verify the effect of the controllers. The error feedback is extended to complex chaotic systems with multiple-time-delay. The CS of real chaotic systems and complex chaotic systems without time-delay are its special cases. [ABSTRACT FROM AUTHOR]

Finding conditions that support synchronization is a fertile and active area of research with applications across multiple disciplines. Here we present and analyze a scheme for synchronizing chaotic dynamical systems by transiently wncoupling them. Specifically, systems coupled only in a fraction of their state space may synchronize even if fully coupled they do not. While for many standard systems coupling strengths need to be bounded to ensure synchrony, transient uncoupling removes this bound and thus enables synchronization in an infinite range of effective coupling strengths. The presented coupling scheme therefore opens up the possibility to induce synchrony in (biological or technical) systems whose parameters are fixed and cannot be modified continuously. [ABSTRACT FROM AUTHOR]

In this paper, we consider parallelization of the loop over elements using OpenMP in FEAP (Taylor, ), which is a research FE code, very popular at universities. Even for a serial version of FEAP (a cluster version also exists) such a parallelization is a non-trivial task due to the existing architecture of this code, which complicates efficient parallelization. First, we compare the serial version of FEAP to the parallel code Warp3D (Dodds et al., ), considering the usage of time and memory. As we found, Warp3D is much faster but uses more memory than FEAP. An analysis of Warp3D helps us to devise our method of parallelization of the loop over elements. Next, we describe several changes in FEAP, which were necessary to parallelize the loop over elements using OpenMP. In particular, the subroutine assembling elemental matrices is identified as crucial to good performance, and several directives for the mutual exclusion synchronization of OpenMP are implemented and tested. Finally, we demonstrate the performance of the parallelized FEAP, designated as ompFEAP, on numerical examples involving 3D and shell elements of FEAP as well as user's elements. We conclude that ompFEAP, using the directive ATOMIC for synchronization of the assembling, provides a very good speedup and efficiency. [ABSTRACT FROM AUTHOR]

This paper is concerned with the global robust synchronization of multiple memristive neural networks (MMNNs) with nonidentical uncertain parameters. A coupling scheme is introduced, in a general topological structure described by a direct or undirect graph, with a linear diffusive term and a discontinuous sign term. First, a set of sufficient conditions are derived based on the Lyapunov stability theory for ascertaining global robust synchronization of coupled MMNNs. Second, a pinning adaptive coupling method is proposed to ensure global synchronization without knowing the bound of parameter uncertainties. Two illustrative examples are discussed to substantiate the theoretical results. [ABSTRACT FROM PUBLISHER]

The mechanisms used to coordinate organ-level contractions of human labor are not universally accepted. We previously proposed a dual mechanism, where electrical activity coordinates cellular contractions into tissue-level regional contractions, and mechanotransduction synchronizes the regional contractions into organ-level contractions. The simulation of this model successfully recapitulates the phasic pressure rises typical of human labor. In this work we extend the simulation to probe the effects of three critical parameters: electrical coupling (which defines functional regions within the uterine wall), enhancement of contractile responses during action potential bursts (action potential multiplier), and the threshold for mechanical recruitment of regional myometrial contractions (threshold). We test how changing the values of these parameters modulates the ability of the uterus to generate synchronized organ-level contractions. Simulations are performed using Mathematica and a nonclassical cellular automaton program we recently published. At least 15 regions are necessary to generate physiologically relevant, synchronized contractions. Organ-level synchronization was improved using higher values for the action potential multiplier. At lower values of the action potential multiplier, synchronized contractions were inhibited when the number of regions was between 32 and 44, suggesting a critical level of electrical coupling is necessary at the onset of labor. Large numbers of low threshold regions resulted in contraction patterns suggestive of hyperstimulation. This work furthers support for the electrical-mechanotransduction mechanism for organ-level synchronization of uterine contractions. The mathematical simulation provides insight regarding how cellular- and tissue-level physiology converge to express synchronized contractions of human labor. [ABSTRACT FROM AUTHOR]

In the present paper, Linear Quadratic Regulator (LQR) and dual properties are employed to solve the observer-based synchronization problem. The synchronization is designed for nominal chaotic system, then it is applied to systems with uncertain parameters and systems with time-delays to investigate its tolerance to such systems. Moreover, to solve the nonlinear problem, which exist in chaotic systems, the optimal linearization technique is adopted to transform the nonlinear system into equivalent linear models. By linearizing the chaotic system and constructing linear models at every operating point, and then applying algebraic Riccati equation, the observer design problem is solved and chaotic synchronization is established. Numerical Simulations are used to demonstrate the effectiveness and feasibility of this design. [ABSTRACT FROM AUTHOR]

Objective: High-frequency electroencephalography (EEG) activity has been observed in association with cognitive processing, including stimulus perception, consciousness and selective attention, in humans. The aim of this study was to compare visual-motor integrated processing between execution and inhibition of a motor response using event-related synchronization (ERS) and desynchronization (ERD) in the 15- to 80-Hz range and to investigate a relationship between event-related potentials (ERPs) and ERS/ERD in 10 normal young subjects. Methods: EEGs were recorded from 21 scalp sites during a visual go/no-go paradigm. For ERPs, 40 artifact-free trials were averaged off-line referenced to linked ear lobes. In the β and γ bands, ERS and ERD were calculated by time-frequency analysis. Results: Go N2 and no-go N2 were elicited 200-250 ms after stimuli, and their distributions were predominant at Fz. Go P3 was predominantly elicited 340-360 ms after stimuli at Pz, whereas no-go P3 was predominantly elicited 360-380 ms after stimuli at Cz. ERD of the β band at Fz and Cz during 300-600 ms showed in the go condition, whereas ERD showed between 39 and 42 Hz at F3 in the no-go condition. Conclusion: Oscillatory cortical response-related β and γ activities differ between the processing of execution and inhibition in motor responses. β ERDs in the sensorimotor areas with go stimuli may be related to motor responses, and γ ERDs in the left frontal area with no-go stimuli may be involved in the processing of inhibition of motor responses. © 2015 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

We report the observation of quantum stochastic synchronization (QSS) in a dissipative quantum system-a moderately damped current-biased Josephson junction. We show that when the junction is biased subcritically by a combination of a constant current and a small sinusoidal modulation signal, forced phase synchronization between the otherwise random, incoherent quantum tunneling and the signal may arise as a consequence of the interplay between quantum fluctuation and the weak periodic drive. It is found that optimal synchronization occurs at a signal frequency fQSS that is comparable to the quantum tunneling rate. We also find a phenomenon called "modulation induced suppression of quantum noise": for signal frequency well below fQSS, the power spectral density of escape time distribution of the junction could be reduced substantially from the floor level of the unmodulated system. Furthermore, we demonstrate that the application of a small signal with proper phase can suppress the average tunneling rate and enhance the stability of the metastable system. Our experimental results agree well with the numerical calculations without the use of adjustable parameters. [ABSTRACT FROM AUTHOR]

Complex networks have, in recent years, brought many innovative impacts to large-scale systems. However, great challenges also come forth due to distinct complex situations and imperative requirements in human life nowadays. This paper attempts to present an overview of recent progress of synchronization of complex dynamical networks and its applications. We focus on robustness of synchronization, controllability and observability of complex networks and synchronization of multiplex networks. Then, we review several applications of synchronization in complex networks, especially in neuroscience and power grids. The present limitations are summarized and future trends are explored and tentatively highlighted. [ABSTRACT FROM AUTHOR]

This paper studies output synchronization problem, formation problem, and regulated synchronization problem for a heterogenous network of discrete-time introspective right-invertible agents. We first propose a decentralized control scheme to solve the output synchronization problem for a set of communication topologies. Moreover, if the synchronization trajectories are assumed to be bounded, a universal controller can be constructed for all communication topologies, which contain a directed spanning tree. The design can be applied to solve the formation problem with arbitrary formation vectors. In the regulated synchronization problem, we assume only the root receives information from exosystem. We then design a decentralized controller to solve the problem for a set of communication topologies. [ABSTRACT FROM AUTHOR]

Given that ground stationary infrastructures for traffic monitoring are barely able to handle everyday traffic volumes, there is a risk that they could fail altogether in situations arising from mass events or disasters. In this work, we present an alternative approach for traffic monitoring during disaster and mass events, which is based on an airborne optical sensor system. With this system, optical image sequences are automatically examined on board an aircraft to estimate road traffic information, such as vehicle positions, velocities and driving directions. The traffic information, estimated in real time on board, is immediately downlinked to a ground station. The airborne sensor system consists of a three-head camera system, a real-time-capable GPS/INS unit, five industrial PCs and a downlink unit. The processing chain for automatic extraction of traffic information contains modules for the synchronization of image and navigation data streams, orthorectification and vehicle detection and tracking modules. The vehicle detector is based on a combination of AdaBoost and support vector machine classifiers. Vehicle tracking relies on shape-based matching operators. The processing chain is evaluated on a large number of image sequences recorded during several campaigns, and the data quality is compared to that obtained from induction loops. In summary, we can conclude that the achieved overall quality of the traffic data extracted by the airborne system is in the range of 68% and 81%. Thus, it is comparable to data obtained from stationary ground sensor networks. [ABSTRACT FROM AUTHOR]

This paper presents an analytical study of synchronization in an array of output-coupled temporal Boolean networks. A temporal Boolean network (TBN) is a logical dynamic system developed to model Boolean networks with regulatory delays. Both state delay and output delay are considered, and these two delays are assumed to be different. By referring to the algebraic representations of logical dynamics and using the semi-tensor product of matrices, the output-coupled TBNs are firstly converted into a discrete-time algebraic evolution system, and then the relationship between the states of coupled TBNs and the initial state sequence is obtained. Then, some necessary and sufficient conditions are derived for the synchronization of an array of TBNs with an arbitrary given initial state sequence. Two numerical examples including one epigenetic model are finally given to illustrate the obtained results. [ABSTRACT FROM AUTHOR]