Outer Synchronization Research Articles

Outer synchronization and outer [formula omitted] synchronization for coupled fractional-order reaction–diffusion neural networks with multiweights

This paper introduces multiple state or spatial-diffusion coupled fractional-order reaction–diffusion neural networks, and discusses the outer synchronization and outer H∞ synchronization problems for these coupled fractional-order reaction–diffusion neural networks (CFRNNs). The Lyapunov functional method, Laplace transform and inequality techniques are utilized to obtain some outer synchronization conditions for CFRNNs. Moreover, some criteria are also provided to make sure the outer H∞ synchronization of CFRNNs. Finally, the derived outer and outer H∞ synchronization conditions are validated on the basis of two numerical examples.

Outer synchronization for two discrete-time complex dynamic networks via the synthesized coupling connections

Outer synchronization for two discrete-time complex dynamic networks via the synthesized coupling connections

Outer Synchronization of Two Muti-Layer Dynamical Complex Networks with Intermittent Pinning Control

This paper regards the outer synchronization of multi-layer dynamical networks with additive couplings via aperiodically intermittent pinning control, in which different layers of each multi-layer network have different topological structures. First, a state-feedback intermittent pinning controller is designed in the drive and response configuration, and sufficient conditions to achieve the outer synchronization are derived based on the Lyapunov stability theory and matrix inequalities. Second, outer synchronization problem of multi-layer networks is discussed by setting an adaptive intermittent pinning controller; an appropriate Lyapunov function is selected to prove the criteria of synchronization between the drive multi-layer network and the response multi-layer network. Finally, three simulation examples are given to show the effectiveness of our control schemes.

Generalized outer synchronization and parameters identification of uncertain delayed hypernetworks with stochastic noises

AbstractSynchronization of hypernetworks has been extensively researched due to its potential applications in various contexts, such as secure communications and power grid engineering. However, the existing works thus far have primarily been devoted to inner synchronization or complete outer synchronization with identical node dynamics and topology structures. To investigate harmonious coexistence between two networks with nonidentical node dynamics and reduce control costs as well, this paper focuses on generalized outer synchronization (GOS) and parameters identification of uncertain delayed hypernetworks with stochastic noises. Regardless of whether the node parameters are known or not, based on Lyapunov stability and the LaSalle‐type invariance principle for stochastic differential equations with multiple delays, some sufficient conditions are exhibited to reach GOS almost surely via adaptive control schemes. Moreover, the unknown node parameter vectors are identified by the designed updating laws. In addition, some corollaries are deduced and indicate that our proposed methods contain single‐layer networks and complete synchronization methods as special cases. Furthermore, numerical simulations are provided to verify the effectiveness of our approaches. In particular, it is revealed that network parameters, including time delays, coupling strengths, and noise intensities, have an impact on the performance of the proposed algorithms.

Outer Topology Network Synchronization Using Chaotic Nodes with Hidden Attractors

This paper addresses the synchronization problem in outer topology networks using chaotic nodes with hidden attractors. Specifically, we analyze bidirectionally coupled networks with various inner–outer coupling topologies to identify the optimal configuration that encourages outer synchronization. The inner–outer coupled networks incorporate a chaotic system capable of generating hidden attractors. To assess the stability of the synchronization state, we conduct numerical simulations and examine the maximum Lyapunov exponent of the generic variational equations. Our results reveal the most suitable bidirectional inner–outer coupling network topology for achieving outer synchronization.

Master-Slave Outer Synchronization in Different Inner-Outer Coupling Network Topologies.

In this work, the problem of master-slave outer synchronization in different inner-outer network topologies is presented. Specifically, the studied inner-outer network topologies are coupled in master-slave configuration, where some particular scenarios concerning inner-outer topologies are addressed in order to disclose a suitable coupling strength to achieve outer synchronization. The novel MACM chaotic system is used as a node in the coupled networks, which presents robustness in its bifurcation parameters. Extensive numerical simulations are presented where the stability of the inner-outer network topologies is analyzed through a master stability function approach.

Asymptotical Outer Synchronization for the Controlled Complex Dynamic Networks with Unknown Bounded Interaction

Asymptotical Outer Synchronization for the Controlled Complex Dynamic Networks with Unknown Bounded Interaction

Asymptotical outer synchronization control of the complex dynamical networks via unknown interaction and links dynamics

The nodes and links connecting them are the two main geometric elements of a complex network. If the nodes and links change over time, all the nodes and all the links are regarded the dynamic systems, respectively, and thus, a complex dynamical network (CDN) can be regarded to be composed of the two interconnected subsystems: the nodes subsystem (NS) and the links subsystem (LS). The outer synchronization happens in two CDNs, which means that the state error between the two NSs converges to zero. However, the dynamics of LS is ignored in the existing literature about the outer synchronization. In addition, the existing literature rarely consider the unknown interaction between two CDNs into the outer synchronization. In view of this, this paper investigates the outer synchronization of two CDNs with the unknown interaction. By using the dynamics of LSs and synthesizing the adaptive control scheme, the outer synchronization is asymptotically achieved. The results in this paper show that the outer synchronization happens when the two LSs can track, respectively, the synthesized auxiliary dynamic tracking targets. Finally, the numerical simulation is given to show the effectiveness of the theoretical results in this paper.

Outer synchronization for a class of discrete‐time complex dynamic networks with unknown bounded interaction

SummaryThis article investigates the outer synchronization for the two discrete‐time complex dynamic networks. First, the more universal mathematical models of the networks with unknown coupling and interaction are proposed. Then, based on the available state of networks and the estimation of summarized unknown parameters shown in the models, the adaptive state feedback controller is synthesized to make the outer synchronization error of two networks converge asymptotically to an arbitrarily small neighborhood at the origin. Finally, the results of simulation show the validity and advantages of the controller.

Topology Identification of Time-Scales Complex Networks

This paper studies a topology identification problem of complex networks with dynamics on different time scales. Using the adaptive synchronization method, some criteria for a successful estimation are obtained. In particular, by regulating the original network to synchronize with an auxiliary chaotic network, this work further explores a way to avoid the precondition of linear independence. When the adaptive controller fails to achieve the outer synchronization, an impulsive control method is used. In the end, we conclude with three numerical simulations. The results obtained in this paper generalize continuous, discrete with arbitrary time step size and mixed cases.

Distortion and instability compensation with deep learning for rotational scanning endoscopic optical coherence tomography.

Optical Coherence Tomography (OCT) is increasingly used in endoluminal procedures since it provides high-speed and high resolution imaging. Distortion and instability of images obtained with a proximal scanning endoscopic OCT system are significant due to the motor rotation irregularity, the friction between the rotating probe and outer sheath and synchronization issues. On-line compensation of artefacts is essential to ensure image quality suitable for real-time assistance during diagnosis or minimally invasive treatment. In this paper, we propose a new online correction method to tackle both B-scan distortion, video stream shaking and drift problem of endoscopic OCT linked to A-line level image shifting. The proposed computational approach for OCT scanning video correction integrates a Convolutional Neural Network (CNN) to improve the estimation of azimuthal shifting of each A-line. To suppress the accumulative error of integral estimation we also introduce another CNN branch to estimate a dynamic overall orientation angle. We train the network with semi-synthetic OCT videos by intentionally adding rotational distortion into real OCT scanning images. The results show that networks trained on this semi-synthetic data generalize to stabilize real OCT videos, and the algorithm efficacy is demonstrated on both ex vivo and in vivo data, where strong scanning artifacts are successfully corrected.

Synchronization of discrete fractional-order complex networks with and without unknown topology.

This paper studies the outer synchronization problem of discrete fractional complex networks (DFCNs) with and without the presence of unknown topology. A discrete complex network with a fractional difference is first established and analyzed. By constructing a suitable Lyapunov function and utilizing properties of the fractional difference, outer synchronization criteria for the DFCNs with and without unknown topology are established based on linear matrix inequalities. Meanwhile, the unknown parameters in the topology structure of the network can be identified by adaptive update laws. In the end, two numerical examples are given to exemplify the validity and applicability of the obtained results.

Asymptotical Outer Synchronization Control for the Complex Dynamic Networks with Unknown Bounded Interaction Via Links Dynamics

Asymptotical Outer Synchronization Control for the Complex Dynamic Networks with Unknown Bounded Interaction Via Links Dynamics

Outer Synchronization of Complex-Variable Networks with Complex Coupling via Impulsive Pinning Control

In this paper, outer synchronization of complex-variable networks with complex coupling is considered. Sufficient conditions for achieving outer synchronization using static impulsive pinning controllers are first derived according to the Lyapunov function method and stability theory of impulsive differential equations. From these conditions, the necessary impulsive gains and intervals for given networks can be easily calculated. Further, an adaptive strategy is introduced to design universal controllers and avoid repeated calculations for different networks. Notably, the estimation algorithms of the impulsive gains and intervals are provided. Finally, three numerical examples are performed to verify the effectiveness of the main results.

Outer synchronization of two different multi-links complex networks by chattering-free control

This paper investigates the outer synchronization problem of two different multi-links complex networks (MLCNs) by chattering-free control. In comparison to the existing works, node dynamics, internal coupling, sub-networks numbers, and node numbers in response networks are not required to be the same as the ones in drive networks. The model proposed is more general. In order to reduce chattering in the synchronization process, some novel chattering-free control schemes are designed to address the synchronization phenomenon of networks. Based on Lyapunov stability theory and Linear matrix inequality, synchronization criteria are established by strict theoretical proof. Numerical simulations and comparison are presented to demonstrate the effectiveness and superiority of the proposed theoretical results.

Aperiodically intermittent pinning outer synchronization control for delayed complex dynamical networks with reaction-diffusion terms

In this paper, we mainly study the outer synchronization problem of complex dynamical networks (CDNs) involving delays and reaction-diffusion terms by aperiodically intermittent pinning control (AIPC). By using piecewise function and Lyapunov-Krasovskii functional method, some criteria for the complete and exponential outer synchronization of the corresponding CDNs with and without the coupling delay are obtained. Furthermore, two numerical examples are provided to illustrate the effectiveness of the obtained results.

Interchangeable outer synchronization of community networks with two spatiotemporal clusters

This paper proposed a novel scheme for the interchangeable outer synchronization (IOS) of community networks, in which the interchangeable realization conditions of two drive-response community networks with two spatiotemporal clusters respectively are derived by the active sliding mode strategy. The numerical results showed that the first (second) cluster in the drive network synchronized with the second (first) cluster in the response network even if the cluster position was asymmetric, which solved the synchronous problem between asymmetrical communities and proved the distinctiveness and effectiveness of the IOS design.

Dynamic coupling in small-world outer synchronization of chaotic networks

In this work, the problem of small-world outer synchronization of chaotic networks using a dynamic intermediary system is studied. The proposed dynamic coupling is applied to the small-world model of Newman and Watts, where the Chua’s chaotic circuit is used like node. Some scenarios are presented where comparative analyses are performed to determine the inner and outer coupling strengths necessary to achieve networks synchronization of both a static diffusive (direct) coupling and the proposed dynamic (indirect) coupling. The comparative analysis between the conventional coupling and the proposed dynamic coupling, which is applied to both the inner and outer synchronization of the studied networks, is carried out through the analysis of the maximum Lyapunov exponent of the generic variational equations.

Realizing generalized outer synchronization of complex dynamical networks with stochastically adaptive coupling

In this paper the generalized outer synchronization between two coupled dynamical networks is investigated. Combining the advantages of adaptive control technique and stochastic coupling method, a new stochastically adaptive coupling method is proposed. We show, both analytically and numerically, that the generalized outer synchronization can be achieved by using the adaptive stochastic coupling. Particularly, the proposed coupling input can adjust its gain rapidly and randomly, which can optimize the required time and energy costs. Our results not only extend the applications of adaptive control technology but also provide a better understanding of the constructive role of noise on network synchronization.

Outer Synchronization of Drive-Response Complex-Valued Complex Networks via Intermittent Pinning Control

This paper is concerned with the outer exponential synchronization of the drive-response complex dynamical networks subject to time-varying delays. The dynamics of nodes is complex valued, the interactions among of the nodes are directed, and the two coupling matrices in the drive system and the response system are also different. The intermittent pinning control is proposed to achieve outer exponential synchronization in the aperiodical way. Some novel sufficient conditions are derived to guarantee outer exponential synchronization of the considered complex-valued complex networks by using the Lyapunov functional method. Finally, two numerical examples are presented to illustrate the effectiveness of the proposed control protocols.