Cluster synchronization of uncertain complex networks with desynchronizing impulse

Cluster synchronization of nonlinear uncertain complex networks with desynchronizing impulse is explored. First of all, a feedback controller is employed, based on the Lyapunov stability theorem and Lipschitz condition, to guarantee that the uncertain complex networks with desynchronizing impulse synchronize with an object trajectory. Furthermore, a synchronizing impulse controller is presented, which is more efficiently and directly used to achieve the cluster synchronization. Finally, numerical examples are examined to show the effectiveness of the proposed methods.

A Feature-based Robust Digital Image Watermarking Against Desynchronization Attacks

In this paper, a new content-based image watermarking scheme is proposed. The Harris-Laplace detector is adopted to extract feature points, which can survive a variety of attacks. The local characteristic regions （LCRs） are adaptively constructed based on scale-space theory. Then, the LCRs are mapped to geometrically invariant space by using image normalization technique. Finally, several copies of the digital watermark are embedded into the nonoverlapped LCRs by quantizing the magnitude vectors of discrete Fourier transform （DFT） coefficients. By binding a watermark with LCR, resilience against desynchronization attacks can be readily obtained. Simulation results show that the proposed scheme is invisible and robust against various attacks which includes common signals processing and desynchronization attacks.

Delayed spontaneous reversibility of left bundle branch block in non-ischemic cardiomyopathy: a case report

Left bundle branch block(LBBB)causes a delay in left ventricular contraction with an unsynchronized ventricular systole.LBBB is an independent determinant of morbi-mortality mainly when associated with cardiomyopathy and left ventricular dysfunction.[1] LBBB due to non-ischemic cardiomyopathy is considered non-reversible.Such irreversibility occurs because LBBB and cardiomyopathy act in a synergic manner in order to maintain both situations.However,there are a few reports in the literature showing that some patients have had an improvement in cardiac function with normalization of QRS and have experienced a reverse remodelling with pharmacological therapy only.[2–4]

Electroencephalogram evidence for mirror neuron activity during the observation of drawn hand motion

The present study used electroencephalography to examine mu rhythm suppression （a putative index of human mirror neuron system activation） at frontal sites （F3, Fz and F4）, central sites （C3, Cz and C4）, parietal sites （P3, Pz and P4） and occipital sites （O1 and O2）, while subjects observed real hand motion （real hand motion condition） and illustrative depictions of hand motion （drawn hand motion condition）. Experimental data revealed that mu rhythm suppression was exhibited in the mirror neuron system when subjects observed both real and drawn hand motion. Moreover, the mu rhythm recorded at the F3, Fz, F4, and Pz poles was significantly suppressed while observing both stimulus types, but no obvious mu suppression occurred at the O1, 02 and 03 poles. These results suggest that the observation of drawings of human hand actions can activate the human mirror neuron system. This evidence supports the hypothesis that the mirror neuron system may be involved in intransitively abstract action understanding.

Electroencephalogram evidence for the activation of human mirror neuron system during the observation of intransitive shadow and line drawing actions

Previous studies have demonstrated that hand shadows may activate the motor cortex associated with the mirror neuron system in human brain. However, there is no evidence of activity of the human mirror neuron system during the observation of intransitive movements by shadows and line drawings of hands. This study examined the suppression of electroencephalography mu waves （8-13 Hz） induced by observation of stimuli in 18 healthy students. Three stimuli were used： real hand actions, hand shadow actions and actions made by line drawings of hands. The results showed significant desynchronization of the mu rhythm （＂mu suppression＂） across the sensodmotor cortex （recorded at C3, Cz and C4）, the frontal cortex （recorded at F3, Fz and F4） and the central and right posterior parietal cortex （recorded at Pz and P4） under all three conditions. Our experimental findings suggest that the observation of ＂impoverished hand actions＂, such as intransitive movements of shadows and line drawings of hands, is able to activate widespread cortical areas related to the putative human mirror neuron system.

Functional localization of the cortical motor area in the brain Electrocorticogram analysis

The method for rapidly, precisely and non-invasively localizing functional regions of the brain is a problem in neuromedicine research. Cortical electrostimulation is the optimal localization method during brain surgery, with a degree of accuracy of approximately 5 mm. However, electrostimulation can damage the cerebral cortex, trigger epilepsy, and extend the operation time. Studies are required to determine whether cortical motor regions can be localized by wavelet analysis from electrocorticograms. In this study, based on wavelet analysis of electrocorticograms, a selection of algorithms for classification of the mu rhythm in the motor regions utilizing experimental data was verified. Results demonstrated that a characteristic quantity of energy ratio in the reconstructed signal was filtered in the d6 （7.81-15.62 Hz） band prior to and following motion events. A characteristic threshold was considered to be 40%. The accuracy of localization detection was 93%. The degree of accuracy was less than 5 mm. The present study avoided the problems of cerebral cortex injury and epilepsy onset, with an operation time of 60 seconds. Therefore, wavelet analysis on electrocorticogram is feasible for localizing cortical motor regions. Furthermore, this localization technique is accurate, safe and rapid.

Synchronization and Desynchronization in Oscillatory Networks

A new class of neural systems called locally binary oscillator networks is proposed. It consists of a large number of binary oscillators, which couple with each other directly only through its nearest neighbours. The properties of synchronization and desynchronization of the networks are investigated. We find that under some criteria locally coupled binary oscillators can yield global synchronization.

Time-Frequency Analysis of EEG Signals Evoked by Voluntary, Stimulated and Imaginary Motions

In order to investigate the characteristics of sensorimotor cortex during motor execution(ME), voluntary, stimulated and imaginary finger flexions were performed by ten volunteer subjects. Electroencephalogram(EEG) data were recorded according to the modified 10-20 International EEG System. The patterns were compared by the analysis of the motion-evoked EEG signals focusing on the contralateral(C3) and ipsilateral(C4) channels for hemispheric differences. The EEG energy distributions at alpha(8—13 Hz), beta(14—30 Hz) and gamma(30—50 Hz) bands were computed by wavelet transform(WT) and compared by the analysis of variance(ANOVA). The timefrequency(TF) analysis indicated that there existed a contralateral dominance of alpha post-movement event-related synchronization(ERS) pattern during the voluntary task, and that the energy of alpha band increased in the ipsilateral area during the stimulated(median nerve of wrist) task. Besides, the contralateral alpha and beta event-related desynchronization(ERD) patterns were observed in both stimulated and imaginary tasks. Another significant difference was found in the mean power values of gamma band(p<0.01)between the imaginary and other tasks. The results show that significant hemispheric differences such as alpha and beta band EEG energy distributions and TF changing phenomena(ERS/ERD) were found between C3 and C4 areas during all of the three patterns. The largest energy distribution was always at the alpha band for each task.

Analysis of the Desynchronization Attack Impact on the E2EA Scheme

The healthcare IoT system is considered to be a significant and modern medical system.There is broad consensus that these systems will play a vital role in the achievement of economic growth in numerous growth countries.Among the major challenges preventing the fast and widespread adoption of such systems is the failure to maintain the data privacy of patients and the integrity of remote clinical diagnostics.Recently,the author proposed an end-to-end authentication scheme for healthcare IoT systems(E2EA),to provide a mutual authentication with a high data rate between the communication nodes of the healthcare IoT systems.Although the E2EA authentication scheme supports numerous attractive security services to resist various types of attack,there is an ambiguous view of the impact of the desynchronization attack on the E2EA authentication scheme.In general,the performance of the authentication scheme is considered a critical issue when evaluating the applicability of such schemes,along with the security services that can be achieved.Therefore,this paper discusses how the E2EA authentication scheme can resist the desynchronization attack through all possible attack scenarios.Additionally,the effect of the desynchronization attack on the E2EA scheme performance is analyzed in terms of its computation and communication costs,based on a comparison with the recently related authentication schemes that can prevent such attack.Moreover,this research paper finds that the E2EA authentication scheme can not only prevent the desynchronization attack,but also offers a low cost in terms of computations and communications,and can maintain consistency and synchronization between the communication nodes of the healthcare IoT systems during the next authentication sessions.

A survey on complex dynamical networks with impulsive effects

We review the research on complex dynamical networks(CDNs)with impulsive effects.We provide a comprehensive and intuitive overview of the fundamental results and recent progress of CDNs with impulsive effects,where impulsive effects are considered from two aspects,i.e.,impulsive control and impulsive perturbation.Five aspects of CDNs with impulsive effects are surveyed,including synchronizing impulses,desynchronizing impulses,adaptive-impulsive synchronization,pinning impulsive synchronization,and CDNs with stochastic and impulsive effects.Finally,conclusions and some future research directions are briefly addressed.

Recruitment of additional corticospinal pathways in the human brain with state-dependent paired associative stimulation

BACKGROUND AND OBJECTIVE Standard brain stimulation protocols modify human motor cortex excitability by modulating the gain of the activated corticospinal pathways. However, the restoration of motor function following lesions of the corticospinal tract requires also the recruitment of additional neurons to increase the net corticospinal output. For this purpose, we investigated a novel protocol based on brain state-dependent paired associative stimulation.

Entangled chimeras in nonlocally coupled bicomponent phase oscillators:From synchronous to asynchronous chimeras

Chimera states,a symmetry-breaking spatiotemporal pattern in nonlocally coupled identical dynamical units,have been identified in various systems and generalized to coupled nonidentical oscillators.It has been shown that strong heterogeneity in the frequencies of nonidentical oscillators might be harmful to chimera states.In this work,we consider a ring of nonlocally coupled bicomponent phase oscillators in which two types of oscillators are randomly distributed along the ring:some oscillators with natural.frequency w1 and others with w2.In this model,the heterogeneity in frequency is measured by frequency mismatch|w1-w2|between the oscillators in these two subpopulations.We report that the nonlocally coupled bicomponent phase oscillators allow for chimera states no matter how large the frequency mismatch is.The bicomponent oscillators are composed of two chimera states,one supported by oscillators with natural frequency wI and the other by oscillators with natural frequency w2.The two chimera states in two subpopulations are synchronized at weak frequency mismatch,in which the coberent oscillators in thern share similar mean phase velocity,and are desynchronized at large frequency mismatch,in which the coherent oscillators in different subpopulations have distinct mean phase velocities.The synchronization-desynchronization transition between chimera states in these two subpopulations is observed with the increase in the frequency mismatch.The observed phenomena are theoretically analyzed by passing to the continuum limit and using the Ott-Antonsen approach.

DESYNCHRONIZATION OF TWO COUPLED LIMIT-CYCLE OSCILLATORS USING AN ASTROCYTE-INSPIRED CONTROLLER

Astrocytes have potential to break synchrony between neurons. Authors＇ recent researches reveal that astrocytes vary the synchronization threshold and provide an appropriate feedback control in stabilizing neural activities. In this study, we propose an astrocyte-inspired controller for desynchronization of two coupled limit-cycle oscillators as a minimal network model. The design procedure consists of two parts. First, based on the astrocyte model, the structure of the dynamic controller is suggested. Then, to have an emcient controller, parameters of controller are tuned through an optimization algo- rithm. The proposed bio-inspired controller takes advantages of three important proper- ties： （1） the controller desynchronizes the oscillators without any undesirable effects （e.g. stopping, annihilating or starting divergent oscillations）; （2） it consumes little effort to preserve the desirable desynchronized state; and （3） the controller is robust with respect to parameters＇ variations. Simulation results reveal the ability of the proposed controller.