Synchronization Control For Complex Networks Research Articles

Private Synchronization Control of Complex Networks Against Eavesdropping Attacks: A Differential Privacy Scheme

Private Synchronization Control of Complex Networks Against Eavesdropping Attacks: A Differential Privacy Scheme

Links synchronization control for complex networks with stochastic links dynamics

Links synchronization control for complex networks with stochastic links dynamics

Disturbance observer‐based PID synchronization control of complex networks with probabilistic interval time‐varying delays and multiple disturbances

AbstractIn this article, the disturbance observer‐based proportional–integral–derivative (PID) control protocol is investigated for synchronization of complex networks with probabilistic interval time‐varying delays and multiple disturbances. For the sake of reducing conservatism, a method of probabilistic interval time‐varying delay is proposed by introducing two certain intervals with known probability distributions. Moreover, two different disturbances are taken into account. One of the disturbances is produced by an exogenous system which acts through the input channel, while the other is usual norm‐bounded disturbance. Simultaneously, a disturbance observer is designed to estimate and compensate the disturbance generated by the exogenous system. By constructing an appropriate Lyapunov–Krasovskii function, a sufficient criterion is obtained to ensure both the exponential synchronization and prescribed performance index. Finally, the simulation examples are employed to demonstrate the validity of the theoretical results.

Adaptive event‐triggered pinning synchronization control for complex networks with random saturation subject to hybrid cyber‐attacks

SummaryThis research is concerned with the problem of pinning based output synchronization control for a complex networks with random saturation vulnerable to hybrid cyber‐attacks via an adaptive event‐triggered scheme (AETS). The output synchronization error systems are subject to suffer from deception attacks, replay attacks, and denial‐of‐service attacks. A novel hybrid cyber‐attack model is first constructed to integrate the three kinds of attacks into a synchronization of complex network. AETSs based on output synchronization errors with the consideration of hybrid cyber‐attacks, have been proposed to reduce the burden of communication. A pinning control strategy is used to decrease the control signal's input. By constructing a Lyapunov functional and using the linear matrix inequality technique, sufficient conditions are provided to ensure the output synchronization error system. Finally, a numerical simulation results are developed to illustrate the efficacy of the proposed theoretical methodology.

Fixed/Preassigned-Time Synchronization Control of Complex Networks With Time Varying Delay

The problem of fixed-time (FXT) and preassigned-time (PAT) synchronization for delayed dynamic complex networks via developing control schemes is concerned. First, by comparing with the existing results, some new results for delayed networks model to ensure the synchronization of FXT and PAT are obtained. Second, some looser conditions are obtained for FXT synchronization, and several more accurate settling time (ST) estimates are established through several special functions. Third, by using some non-trivial control strategy, the PAT synchronization is investigated with limited control gains, and the synchronization time is able to specified in advance on the basis of practical need and is not relate to any parameter and any initial value. In particular, as a distinct form, the essential conditions for the FXT and PAT synchronization are obtained for the coupled neural networks. last, the improved the FXT and PAT synchronization results of dynamic delayed networks are demonstrated by one numerical example.

Event-triggered synchronization control of complex networks with adaptive coupling strength

The event-triggered synchronization control problem is concerned for a class of complex networks with nonlinearly coupling function and adaptive coupling strength. Given a state-based event-trigger mechanism and the threshold, an event-triggered control method is introduced to make complex networks achieve exponential synchronization. By combining the Lyapunov stability theory and the knowledge of graph theory, a sufficient condition is established such that complex networks can achieve exponential synchronization. Then, the feasibility of the event-triggered control is analyzed. Moreover, the second-order Kuramoto oscillators is taken into account. And the event-triggered control strategy is used to make the oscillators achieve exponential synchronization. Meanwhile, two simulation results about the second-order Kuramoto oscillators are given to show the effectiveness of results.

Decentralized event‐triggered synchronization control for complex networks with nonperiodic DoS attacks

AbstractThis article focuses on the issue of decentralized event‐triggered synchronization control for complex networks (CNs) under nonperiodic denial‐of‐service (DoS) attacks. First, to alleviate the pressure on network bandwidth, a decentralized event‐triggered scheme is employed at each coupled node to decide whether the synchronization signal is transmitted to the communication network. Then, an event‐based synchronization error model is established for CNs under DoS attacks, where the communication network is assumed to be composed of multiple transmission channels and DoS attacks will independently compromise each of channels. Based on the constructed model, sufficient conditions that assuring the secure synchronization of the system are analyzed with the assistance of Lyapunov stability theory. Meanwhile, the synchronization controller gains are designed by solving a set of linear matrix inequalities. The efficiency of the study is finally validated by simulations.

Adaptive Event-Based Non-Fragile Output Pinning Synchronization Control for Complex Networks With Random Saturations and Cyber-Attacks

This paper addresses the adaptive event-triggered non-fragile output pinning synchronization control for complex networks subject to random saturations and cyber-attacks. An adaptive event-triggered scheme (AETS) based on the output synchronization error is proposed to save network bandwidth, and a pinning control strategy is employed to reduce the input of control signal. Considering the effect of AETS, randomly occurring saturations and cyber-attacks on the drive and response systems, we investigate a novel output security synchronization error model, and then design an event-triggered non-fragile controller such that the asymptotic stability of the error system can be guaranteed. Meanwhile, we obtain the controller gains and event-triggered matrices in terms of solving the linear matrix inequalities (LMIs). Finally, a simulation example is provided to verify the design method.

Finite/fixed-time synchronization for complex networks via quantized adaptive control

<p style='text-indent:20px;'>In this paper, a unified theoretical method is presented to implement the finite/fixed-time synchronization control for complex networks with uncertain inner coupling. The quantized controller and the quantized adaptive controller are designed to reduce the control cost and save the channel resources, respectively. By means of the linear matrix inequalities technique, two sufficient conditions are proposed to guarantee that the synchronization error system of the complex networks is finite/fixed-time stable in virtue of the Lyapunov stability theory. Moreover, two types of setting time, which are dependent and independent on the initial values, are given respectively. Finally, the effectiveness of the control strategy is verified by a simulation example.</p>

Observer-based synchronization control for complex networks against asynchronous attacks

Under the framework of cyber-physical systems (CPSs), this paper investigates the secure synchronization control problem of complex networks against asynchronous attacks. Different from the previous works that considered either connection attack on network connections or denial-of-service (DoS) attack in control (controller-to-actuator) channels, the asynchronous case of both types of attacks in complex networks is taken into account here. Besides, to overcome the difficulty that system states are not available for controllers, the pinning-nodes-based observer is designed to estimate all system states only using the measurements of pinning nodes rather than all ones. Such an observer is very realistic, especially for large-scale complex systems. By establishing a piecewise Lyapunov function, the secure synchronization criteria of complex networks under the considered asynchronous attacks are obtained. Finally, a numerical example and its simulations are exhibited to confirm the availability of the developed theoretical outcomes.

Pinning synchronization control of complex networks with partial couplings

In this article, the pinning synchronization problem of complex networks with a target node via sampled-data communications is considered. Due to partial couplings among the nodes in complex networks, a decoupling method is adopted to investigate each channel of complex networks independently. By constructing a time-dependent Lyapunov function, it is proved that the pinning synchronization of complex networks with a target node can be achieved if the control parameters are appropriately selected. Furthermore, further study is needed to investigate the pinning synchronization of complex networks in the presence of constant delay. A novel criterion is obtained using Jensen’s inequality and Wirtinger’s inequality. It is worth noting that the lower and upper bounds of the sampling intervals can be calculated by linear matrix inequality box of MATLAB. Theoretical results are well verified through a numerical simulation.

Adaptive event-triggered synchronization control for complex networks with quantization and cyber-attacks

This paper investigates the adaptive event-triggered synchronization control problem for a class of complex networks with quantization and cyber-attacks. For reducing the burden of communication and computation, an adaptive event-triggered scheme and a logarithmic quantizer are both introduced. Firstly, considering the effect of adaptive event-triggered sampling, quantization and cyber-attacks, a novel synchronization error model is established. By using Lyapunov functional method, some sufficient conditions are derived to guarantee the asymptotic stability of the augmented synchronization error system. Moreover, the co-design of the controller and adaptive event-triggered scheme are also solved in terms of solving the solution of linear matrix inequality(LMI). Finally, a numerical example is exploited to show the effectiveness of the proposed method.

Adaptive synchronization of complex networks with general distributed update laws for coupling weights

This paper discusses adaptive synchronization control for complex networks interacted in an undirected weighted graph, and aims to provide a novel and general approach for the design of distributed update laws for adaptively adjusting coupling weights. The proposed updating laws are very general in the sense that they encompass most weight update laws reported in the literature as special cases, and also provide new insights in the analysis of network system evolution and graph weight convergence. We show a rigorous proof for the synchronization stability of the overall complex network to a synchronized state, and demonstrate the convergence of adaptive weights for each edge to some bounded constants. A detailed comparison with available results is provided to elaborate the new features and advantages of the proposed adaptive strategies as compared with conventional adaptive laws. The effectiveness of the proposed approach is also validated by several typical simulations.

Extended dissipative memory sampled-data synchronization control of complex networks with communication delays

This paper focuses on the problem of extended dissipative sampled-data synchronization for a class of complex networks with communication delays. It designs for the first time an aperiodic memory sampled-data feedback control protocol to solve extended dissipative synchronization issues of such networks. In contrast to most existing works, the constructed Lyapunov functional is not necessarily positive definite on sampling intervals, and the extended dissipative index can be transformed into the H∞ performance, passivity performance and the dissipative performance in a unified framework. With the aid of the modified free-matrix-based integral inequality (MFMBII), a less conservative sufficient criterion is obtained such that the synchronization error system is stability and extended dissipative. Two simulation examples are carried out to demonstrate the superiority and advantages of the proposed method.

Event-triggered synchronization control for complex networks with actuator saturation

This paper investigates the problem of event-triggered synchronization control for complex networks. Each node is subject to actuator saturation. Based on Lyapunov theory and algebraic graph theory, novel sufficient conditions are derived, under which the synchronization error system is asymptotically stable. Compared with the existing results, the proposed event-riggered synchronization control strategy can be applied to the network with the unknown coupling configuration matrix. A numerical example is presented to demonstrate the effectiveness of the proposed control strategy.

Distributed synchronization control of complex networks with communication constraints

This paper is concerned with the distributed synchronization control of complex networks with communication constraints. In this work, the controllers communicate with each other through the wireless network, acting as a controller network. Due to the constrained transmission power, techniques such as the packet size reduction and transmission rate reduction schemes are proposed which could help reduce communication load of the controller network. The packet dropout problem is also considered in the controller design since it is often encountered in networked control systems. We show that the closed-loop system can be modeled as a switched system with uncertainties and random variables. By resorting to the switched system approach and some stochastic system analysis method, a new sufficient condition is firstly proposed such that the exponential synchronization is guaranteed in the mean-square sense. The controller gains are determined by using the well-known cone complementarity linearization (CCL) algorithm. Finally, a simulation study is performed, which demonstrates the effectiveness of the proposed design algorithm.

Event-triggered synchronization control for complex networks with uncertain inner coupling

This paper is concerned with the event-triggered synchronization control problem for a class of complex networks with uncertain inner couplings. The uncertain inner coupling under consideration is characterized in terms of the interval matrix. In order to save the communication and computation resources, the event-based mechanism is adopted and the event-triggered synchronization control scheme is proposed for the complex networks. First, we transform the event-triggered synchronization control problem into the exponential stabilization problem for a new class of dynamical systems with multiple delays. Then, by employing the Lyapunov stability theory, we derive a sufficient condition under which the multi-delayed system is exponentially stable. Subsequently, a set of event-triggered synchronization controllers is designed in terms of the solution to a linear matrix inequality that can be solved effectively by using available software. Finally, a numerical simulation example is presented to show the effectiveness of the proposed event-triggered control scheme.

Non‐fragile synchronization control for complex networks with additive time‐varying delays

In this article, a synchronization problem for complex dynamical networks with additive time‐varying coupling delays via non‐fragile control is investigated. A new class of Lyapunov–Krasovskii functional with triple integral terms is constructed and using reciprocally convex approach, some new delay‐dependent synchronization criteria are derived in terms of linear matrix inequalities (LMIs). When applying Jensen's inequality to partition double integral terms in the derivation of LMI conditions, a new kind of linear combination of positive functions weighted by the inverses of squared convex parameters appears. To handle such a combination, an effective method is introduced by extending the lower bound lemma. Then, a sufficient condition for designing the non‐fragile synchronization controller is introduced. Finally, a numerical example is given to show the advantages of the proposed techniques. © 2014 Wiley Periodicals, Inc. Complexity 21: 296–321, 2015

Robust synchronization control for complex networks with disturbed sampling couplings

This paper is concerned with the problems of asymptotic synchronization and L2 performance specification of a class of nonlinear complex networks against disturbed discrete-time sampling couplings. The sampling coupled network is converted into an effective perturbed coupling network. The perturbations and nonlinearities of nodes are supposed to be influenced by some internal and external factors of networks, which are depended on the transmitted signals and restricted by some constant bounds respectively. An adaptive mechanism is designed to estimate the dependency rate of signals and constant bounds. Then the robust adaptive compensation controllers are constructed to automatically eliminate the effects of perturbations and nonlinearities based on the estimations, and simultaneously to specify the L2 performance of networks. Through Lyapunov functions and adaptive schemes, the achievement of asymptotic synchronization of the closed-loop adaptive complex networks is obtained with satisfying a specified L2 performance criterion. Finally, numerical simulations are included to validate the effectiveness of the proposed method.

Phase synchronization control of complex networks of Lagrangian systems on adaptive digraphs

This paper presents a formation control and synchronization method that utilizes adaptive network topologies for a class of complex dynamical networks comprised of a large number of highly-nonlinear Euler–Lagrange (EL) systems. A time-varying and switching network topology, constructed by the adaptive graph Laplacian matrix, relaxes the standard requirement of consensus stability, even permitting exponential synchronization on an unbalanced digraph or a weakly connected digraph that can sporadically lose connectivity. The time-varying graph Laplacian matrix is adapted by an adaptive control scheme based on relative positions and errors of synchronization and tracking. The adaptive graph Laplacian is integrated with a phase synchronization controller that synchronizes the relative motions of EL systems moving in elliptical orbits, thereby yielding a smaller synchronization error than an uncoupled tracking control law in the presence of bounded disturbances and modeling errors. An example of reconfiguring hundreds of spacecraft in Low Earth Orbit shows the effectiveness of the proposed phase synchronization controller for a large number of complex EL systems moving in periodic elliptical orbits.