Time-varying Coupling Delays Research Articles

Robust [formula omitted] synchronization for parabolic complex networks with coupling time-varying delays

This paper delves into the robust H∞ synchronization for diffusion-type parabolic complex networks (PCNs) characterized by second-order nonlinear partial differential equations (PDEs). Given that the potential deterioration of network performance or the loss of network synchronization caused by external disturbances and time delays, the analysis and synthesis results for the robust H∞ synchronization of the PCNs with coupling time-varying delays are derived with and without the utilization of the distributed adaptive state feedback control protocol. A numerical example is employed to validate the effectiveness of the acquired H∞ synchronization results and the adaptive protocol.

Local Synchronization of Directed Lur'e Networks With Coupling Delay via Distributed Impulsive Control Subject to Actuator Saturation.

This article studies the local exponential synchronization synthesis problem of directed Lur'e networks with coupling time-varying delay under the distributed impulsive control subject to actuator saturation. First, by utilizing proof by contradiction, impulsive comparison principle, and latest improved convex hull representation of saturation function, some delay-independent sufficient criteria for local exponential synchronization are presented in the form of bilinear matrix inequalities. Meanwhile, a novel method with less conservatism is developed to estimate the domain of attraction, which is radically different from the traditional method by means of contractive invariant set. Second, optimization problems constrained by the transformed linear matrix inequalities are established to acquire the maximum estimates of both the domain of attraction and average impulsive interval (AII), which are conveniently solved by the YALMIP toolbox in MATLAB software. Finally, a numerical simulation is rendered to demonstrate the effectiveness and advantages of the proposed theoretical results.

Synchronization of multi-weighted complex networks with mixed variable delays and uncertainties via impulsive pinning control

In this paper, the synchronization problem in nonlinearly-coupled multi-weighted complex networks with parameter uncertainties and multiple delays, where both internal time-varying delays and multiple coupling time-varying delays are included, is investigated by adopting a pinning impulsive control scheme, which combines the merits of pinning control and impulsive control. Impulsive pinning control ratio has been applied to select controlled nodes at each impulsive instant. Based on the Lyapunov function method, sufficient conditions for achieving complete synchronization of multi-weighted complex networks have been derived. And numerical simulations are presented to demonstrate the validity and efficacy of our derived theoretical results, which show that under the criteria proposed in this paper, multi-weighted complex networks with parameter uncertainties and multiple delays, could achieve complete synchronization by applying pinning impulsive control. Besides, taking bus lines as the network nodes, a public traffic roads network model with multi-weights is established and analyzed numerically as an application of the proposed multi-weighted complex network model.

Event-triggered H ∞ control of complex dynamical networks subject to stochastic cyber-attacks by new two-sided delay-dependent LKF functional

ABSTRACT This article deals with the problem of event-triggered control of complex dynamical networks (CDNs) subject to stochastic cyber-attacks and random coupling delays. Hackers may abuse the system by injecting malicious activity into communication networks. Two types of non-linear functions for cyber-attacks, time-varying coupling delays, respectively, and a set of random variables satisfying the Bernoulli distribution are proposed. Against complex dynamical networks, an attacker has the capacity to change the transmitted data. So the traditional control method can be a major challenge, and it is essential to respond to cyber-attacks of this kind. An event-triggered mechanism (ETM) was implemented to avoid losing limited bandwidth. The input delay method is then used to build a time-varying sample under stochastic cyber-attacks. The stability criterion of the developed system model and the display expression of control parameters are then established using a new two-sided delay-dependent Lyapunov–Krasovskii functional (LKF) and linear matrix inequality (LMI) techniques. Lastly, two numerical examples, including the inverted pendulum application, are presented to illustrate the effectiveness and feasibility of the derived theoretical results.

Finite-Time Bipartite Synchronization of Networked Systems with Time-Varying and Random Coupling Delays

Finite-Time Bipartite Synchronization of Networked Systems with Time-Varying and Random Coupling Delays

State Estimation-Based Hybrid-Triggered Controller Design for Synchronization of Repeated Scalar Nonlinear Complex Dynamical Networks

The goal of this work is to examine the issue of state estimation-based synchronization of nonlinear complex dynamical networks that are prone to external disturbances, repeated scalar nonlinearities and time-varying coupling delays. In a nutshell, hybrid-triggered communication transmission nonfragile control design with respect to the estimated states and extended dissipative theory is designed, which comprises of both the time and event-triggered mechanisms, and a hybrid generator is presented between the sensor and controller. More preciously, a stochastic variable satisfying the Bernoulli random binary distribution is utilized to represent the phenomenon of random transmission between the time and event-triggered mechanism. Furthermore, delay-dependent adequate conditions for ensuring the synchronization of the addressed system are developed in the form of linear matrix inequalities. And, the requisite gain matrices and hybrid-triggered parameters are evaluated with the help of solving these procured conditions. Lastly, a numerical example with an application to memristor-based Chua’s circuit model is demonstrated to ensure the effectiveness of established control technique.

Combination projection synchronization of fractional-order complex dynamic networks with time-varying delay couplings and disturbances

In this paper, the problem of combination projection synchronization of fractional-order complex dynamic networks with time-varying delay couplings and external interferences is studied. Firstly, the definition of combination projection synchronization of fractional-order complex dynamic networks is given, and the synchronization problem of the drive-response systems is transformed into the stability problem of the error system. In addition, time-varying delays and disturbances are taken into consideration to make the network synchronization more practical and universal. Then, based on Lyapunov stability theory and fractional inequality theory, the adaptive controller is formulated to make the drive and response systems synchronization by the scaling factors. The controller is easier to realize because there is no time-delay term in the controller. At last, the corresponding simulation examples demonstrate the effectiveness of the proposed scheme.

Saturated and asymmetric saturated impulsive control synchronization of coupled delayed inertial neural networks with time-varying delays

This paper considers control systems with impulses that are saturated and asymmetrically saturated which are used to examine the synchronization of inertial neural networks (INNs) with time-varying delay and coupling delays. Under the theoretical discussions, mixed delays, such as transmission delay and coupling delay are presented for inertial neural networks. The addressed INNs are transformed into first order differential equations utilizing variable transformation on INNs and then certain adequate conditions are derived for the exponential synchronization of the addressed model by substituting saturation nonlinearity with a dead-zone function. In addition, an asymmetric saturated impulsive control approach is given to realize the exponential synchronization of addressed INNs in the leader-following synchronization pattern. Finally, simulation results are used to validate the theoretical research findings.

Function Projective Synchronization of Two Complex Networks with Unknown Sector Nonlinear Input and Multiple Time-Varying Delay Couplings

This paper deals with the function projective synchronization of two complex dynamic networks with unknown sector nonlinear input, multiple time-varying delay couplings, model uncertainty, and external interferences. Based on Lyapunov stability theory and inequality transformation method, the robust adaptive synchronization controller is designed, by which the drive and response systems can achieve synchronization according to the function scaling factor. Different from some existing studies on nonlinear system with sector nonlinear input, this paper studies the synchronization of two complex dynamic networks when the boundary of sector nonlinear input is unknown. The controller does not include the boundary value of the sector nonlinear input and the time delay term, so it is more practical and relatively easy to implement. The corresponding simulation examples demonstrate the effectiveness of the proposed scheme.

Robust Asynchronous Filtering for Discrete-Time T–S Fuzzy Complex Dynamical Networks Against Deception Attacks

In this article, the robust asynchronous filtering problem is investigated for a class of discrete-time T–S fuzzy complex dynamical networks subjected to random coupling delays and deception attacks. Specifically, the deception attacks are considered in the filter, where the adversary attempts to inject some false information data in the measurement output to modify the transmitted signal in the communication networks. We introduce, respectively, two sets of stochastic variables satisfying the Bernoulli distribution to depict the probability of the data transmitted by the network being subjected to time-varying coupling delays and deception attacks. By using Lyapunov–Krasovskii stability theory and Abel lemma-based finite-sum inequality, a new set of sufficient conditions is established, which ensures the stochastic stability of the resulting error system with a prescribed mixed <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$H_\infty$</tex-math></inline-formula> and passivity performance index. The proposed filter parameters are obtained by solving linear matrix inequalities. Ultimately, both the effectiveness and advantages of the proposed asynchronous filter with deception attacks are verified by two numerical examples including a tunnel diode circuit model.

Pinning synchronization of complex networks with time-varying outer coupling and nonlinear multiple time-varying delay coupling

This article studies the pinning control problem for complex networks with time-varying outer coupling and nonlinear multiple time-varying delay coupling. The design aim is to provide appropriate pinning feedback controllers such that the nodes converge to the consistent state as well as the equilibrium point, periodic orbit or chaotic orbit of the nonlinear part of the node dynamic. Based on Lyapunov function theory, appropriate positive-definite functions are constructed, and sufficient synchronization criteria for two kinds of complex networks with different time-varying delay coupling are obtained respectively. Meanwhile, the boundary of the time-varying outer coupling and its influence on the synchronization are investigated. The theoretical results are extended to complex networks with general time-varying delay coupling. Simulation results on complex networks consisting of six nonidentical Chua’s circuits with time-varying outer coupling and nonlinear multiple time-varying delay coupling are presented to demonstrate the effectiveness of the proposed approaches.

Intermittent Control Strategy for Synchronization Analysis of Time-Varying Complex Dynamical Networks

The pth moment exponential synchronization (PMES) problem for time-varying complex dynamical networks (CDNs) with multiple time-varying delays (TCDNMTDs) by aperiodically intermittent control is studied in this paper. Compared with related work, the coupling structure of CDNs is time varying. Also, internal time-varying delays and coupling time-varying delays are taken into consideration and they are different from each other. It is worth emphasizing that the intermittent control scheme proposed here is nonperiodical. Some criteria are derived to make TCDNMTDs achieve PMES by using the Lyapunov method and graph theory. Additionally, we also consider the synchronization of second-order Kuramoto oscillators and coupled Chua's circuits and some numerical simulations are presented to verify the validity of our results.

Observer-based synchronization of fractional-order Markovian jump multi-weighted complex dynamical networks subject to actuator faults

This paper is concerned with an observer-based robust H∞ synchronization problem for a class of fractional-order multi-weighted complex dynamical networks subject to Markovian jump parameters, actuator faults and time-varying coupling delay by using fault-tolerant control scheme. The considered actuator fault model is a general one, which consisting of both linear and nonlinear fault terms. Further, by employing a continuous frequency distributed equivalent model and using indirect Lyapunov approach, a new set of sufficient conditions is derived to ensure the asymptotic synchronization of the addressed system in the mean square sense with a prescribed H∞ performance index. In particular, by constructing monochromatic Lyapunov functional and utilizing extended Wirtinger-based integral inequality the required sufficient conditions are developed in terms of linear matrix inequalities. Finally, two numerical examples including financial model are provided to illustrate the effectiveness of the obtained results.

Formula omitted] filtering for nonlinearly coupled complex networks subjected to unknown varying delays and multiple fading measurements

In this paper, the robust filtering problem for uncertain complex networks with time-varying state delay and stochastic nonlinear coupling based on H∞ performance criterion is studied. The random connections of coupling nodes are represented by utilizing independent random variables and the multiple fading measurements phenomenon is characterized by introducing diagonal matrices with independent stochastic elements. Moreover, the probabilistic time-varying delays in the measurement outputs are described by white sequences with the Bernoulli distributions. Furthermore, All system’s matrices are supposed to have uncertainty and a quadratic bound is assumed for nonlinear part of the network. This bound can be obtained by solving a sum of squares (SOS) optimization problem. By applying the Lyapunov theory, we design a robust filter for each node of the network so that the filtering error system is asymptomatically stable and the H∞ performances are met. Then, the parameters of the filters are achieved by solving a linear matrix inequality (LMI) feasibility problem. Finally, the applicability and performance of the proposed H∞ filtering approach are demonstrated via a practical example.

Robust non-fragile memory feedback control for multi-weighted complex dynamical networks with randomly occurring gain fluctuations

This paper deals with the robust observer-based synchronisation problem for a class of complex dynamic networks subject to multi-weights, time-varying coupling delay and external disturbance. Specifically, the gain fluctuation appears in the proposed controller and is represented in terms of a random variable obeying the Bernoulli distribution. The main objective of this paper is to design a non-fragile memory state feedback controller such that the resulting error system is stochastically synchronised under a prescribed performance level . First, a Luenberger-type state observer is constructed to estimate the state variables of the addressed system. Second, by constructing an appropriate Lyapunov–Krasovskii functional and using Wirtinger-based integral inequality techniques, the required set of sufficient conditions for the synchronisation of the proposed system is established in the form of linear matrix inequalities. In the end, two numerical examples are provided to demonstrate the validity and feasibility of the developed theoretical results.

New Delay-Dependent Synchronization Criteria of Complex Dynamical Networks With Time-Varying Coupling Delay Based on Sampled-Data Control via New Integral Inequality

In this work, the issue of synchronization control for complex dynamical networks with time-varying coupling delay based on sampled-data is addressed. First, the sampled-data control is transformed into the bounded sampling period with time-varying delay. As a result, this model is converted to the investigation for synchronization of complex networks with multiple time-varying delays. Second, an appropriate Lyapunov-Krasovkii functional (LKF) is constructed, which composites of double and triple integral terms in quadratic form. Third, we propose a new integral inequality including a reciprocally convex technique which leads to a better condition. Fourth, the solution for the controller gain matrix is obtained by solving linear matrix inequalities (LMIs) with available software such that the synchronization error system is exponentially stable. Finally, the effectiveness and less conservatism of our proposed method are demonstrated via numerical examples.

ℋ∞/passive non-fragile synchronisation of Markovian jump stochastic complex dynamical networks with time-varying delays

This paper deals with the problem of /passive non-fragile synchronisation for a class of complex dynamical networks subject to Markovian jumping time-varying coupling delays. Gain variation is represented by a stochastic variable that is assumed to satisfy the Bernoulli distribution with white sequences. The synchronisation error system became stable through our designed controller. By Lyapunov–Krasovskii stability theory, a new stochastic synchronisation criterion is established for the considered network in terms of linear matrix inequality (LMI). An illustration is given to show effectiveness of the proposed theoretical results.

Adaptive and Exponential Synchronization of Uncertain Fractional-Order T-S Fuzzy Complex Networks With Coupling Time-Varying Delays via Pinning Control Strategy

This article investigates the adaptive and exponential synchronization problems of fractional-order Takagi-Sugeno (T-S) fuzzy complex networks (FOTSFCN) with coupling time-varying delays and uncertainty. Firstly, the FOTSFCN model is established by embedding T-S fuzzy logic to reduce the complexity and robustness of the FOTSFCN. Secondly, based on the adaptive pinning control strategy, we obtain the asymptotic synchronization and exponential synchronization criteria to achieve synchronous control of FOTSFCN. Furthermore, according to the Lyapunov stability theory, we prove that the FOTSFCN controlled by the proposed controller is robust stable and the effect of coupling time-varying delays and uncertain disturbances on the tracking error can be subsided in view of the linear matrix inequalities (LMIs). Finally, the effectiveness and applicability of the theoretical results are presented through two illustrative examples.

Delay-dependent synchronization of T-S fuzzy Markovian jump complex dynamical networks

In this paper, a delay-dependent synchronization criteria for Markovian jump complex dynamical networks subject to time-varying coupling delays and external disturbances are proposed via Takagi-Sugeno (T-S) fuzzy approach. The class of Markovian jump complex dynamical networks is described by a fuzzy model composed of two levels such as a crisp level which represents the jumps and a fuzzy level which describes the system nonlinearities. An asymptotic synchronization criterion is obtained by employing fuzzy controller with the mixed H∞ and passivity performance index ν>0. Further, by constructing a novel Lyapunov-Krasovskii functional along with the extended integral inequality and using the properties of Kronecker product and convex combination approach, a set of sufficient constraints is derived in the form of linear matrix inequalities and checked for its feasibility using MATLAB software. At last, numerical simulations including the Lorentz system are given to demonstrate the applicability and effectiveness of the developed results.

Synchronization Analysis for Stochastic T-S Fuzzy Complex Networks with Markovian Jumping Parameters and Mixed Time-Varying Delays via Impulsive Control

In this paper, we propose and explore the synchronization examination for fuzzy stochastic complex networks’ Markovian jumping parameters portrayed by Takagi-Sugeno (T-S) fuzzy model with mixed time-varying coupling delays via impulsive control. The hybrid coupling includes time-varying discrete and distributed delays. Based on appropriate Lyapunov–Krasovskii functional (LKF) approach, Newton–Leibniz formula, and Jensen’s inequality, the stochastic examination systems and Kronecker product to create delay-dependent synchronization criteria that guarantee stochastically synchronous of the proposed T-S fuzzy stochastic complex networks with mixed time-varying delays. Adequate conditions for the synchronization criteria for the frameworks are established in terms of linear matrix inequalities (LMIs). At long last, numerical examples and simulations are given to demonstrate the correctness of the hypothetical outcomes.