This paper is concerned with how multi-agent networks achieve finite-time consensus using distributed event-driven control. Due to the hybrid nonlinearities arising from the nonsmooth control and the ...triggering condition, finite-time consensus analyses are more challenging with event-driven control than with continuous-time control. We study agents with single integrator dynamics and scalar states and present a distributed event-driven control protocol for the finite-time consensus, with comparison to continuous-time control. It is shown that using the proposed event-driven control scheme, agents can reach consensus within a limited time and without Zeno behavior. We also obtain an estimate for the settling time and demonstrate that it is not only related to the initial condition and network connectivity, but is also linked with the event-triggering condition. Simulations are given to demonstrate the theoretical results.
Delayed impulsive controllers are proposed in this paper to enable the agents in a class of second-order multiagent systems (MASs) to achieve state consensus, based, respectively, on the relative ...full-state and partial-state sampled-data measurements among neighboring agents. It is a challenging task to analyze the consensus behaviors of the considered MASs as the dynamics of such MASs will be subjected to joint effects from delay-dependent impulses, aperiodic sampling, and switchings among different communication graphs. A novel analytical approach, based upon the discretization method, state augmentation, and linear state transformation, is developed to establish the sufficient consensus criteria on the range of the impulsive intervals and the control parameters. Remarkably, it is found that consensus in the closed-loop MASs can be always ensured by skillfully selecting the control parameters as long as the nonuniform delays and the impulsive intervals are bounded. A numerical example is finally performed to validate the effectiveness of the proposed delayed impulsive controllers.
Circular RNAs (circRNAs) play important roles in human cancer progression. Their high stability and tissue specificity make circRNAs important molecular targets for clinical diagnosis, treatment and ...prognosis. However, the functions and molecular mechanisms of circRNA WHSC1 in endometrial cancer are unknown. CircWHSC1 expression in normal endometrial and endometrial cancer tissues was detected using PCR. Overexpression or knockdown of circWHSC1 in endometrial cancer cell lines HEC‐1B or Ishikawa, respectively, cell function experiments were used to detect the impact of circWHSC1 on endometrial cancer cells. A nude mouse xenograft model was used to detect changes in tumorigenesis of HEC‐1B cells after circWHSC1 overexpression. Bioinformatics and dual luciferase reporter gene technology were used to predict and validate the sponging ability of circWHSC1 on microRNAs. Gene expression changes were detected by using Western blotting. CircWHSC1 expression was increased in endometrial cancer tissues. CircWHSC1 overexpression promoted the proliferation, migration and invasion of endometrial cancer cells and decreased apoptosis. CircWHSC1 knockdown had the opposite effect. CircWHSC1 overexpressed nude mice showed increased tumorigenicity. Bioinformatics predicted that circWHSC1 binds to miR‐646, which was confirmed using luciferase reporter gene assays. High expression of miR‐646 could reverse the effect of circWHSC1 on endometrial cancer cells. Western blotting showed increased or decreased levels of nucleophosmin 1 (NPM1), an miR‐646 downstream target, after circWHSC1 overexpression or knockdown, respectively. CircWHSC1 promotes endometrial cancer development through sponging miR‐646 and targeting NPM1.
This paper addresses the finite-time and fixed-time bipartite average tracking (BAT) problems in multi-agent systems (MASs) subject to bounded disturbances. A novel non-smooth protocol is first ...constructed on the basis of utilizing the finite-time control method, which can realize the finite-time BAT with structurally balanced graph. Then, the fixed-time BAT problem is dealt with nonlinear fixed-time algorithm, the setting time of which is obtained without depending on initial states. By employing Lyapunov stability theory, some sufficient criteria are obtained to achieve the finite-time and fixed-time BAT for MASs with disturbances. Numerical examples are finally developed for illustration.
The important topic of multistability of continuous-and discrete-time neural network (NN) models has been investigated rather extensively. Concerning the design of associative memories, ...multistability of delayed hybrid NNs is studied in this paper with an emphasis on the impulse effects. Arising from the spiking phenomenon in biological networks, impulsive NNs provide an efficient model for synaptic interconnections among neurons. Using state-space decomposition, the coexistence of multiple equilibria of hybrid impulsive NNs is analyzed. Multistability criteria are then established regrading delayed hybrid impulsive neurodynamics, for which both the impulse effects on the convergence rate and the basins of attraction of the equilibria are discussed. Illustrative examples are given to verify the theoretical results and demonstrate an application to the design of associative memories. It is shown by an experimental example that delayed hybrid impulsive NNs have the advantages of high storage capacity and high fault tolerance when used for associative memories.
In this paper, the leader-following output consensus problem for a class of uncertain nonlinear multiagent systems with unknown control directions is investigated. Each agent system has nonidentical ...dynamics and is subject to external disturbances and uncertain parameters. The agents are connected through a directed and jointly connected switching network. A novel two-layer distributed hierarchical control scheme is proposed. In the upper layer, to save the communication resources and to handle the switching networks, an event-triggered communication scheme is proposed, and a Zeno-free event-triggered mechanism is designed for each agent to generate the asynchronous triggering time instants. Furthermore, to avoid the continuous monitoring of the system states, a Zeno-free self-triggering algorithm is proposed. In the lower layer, to handle the unknown control directions problem and to achieve the output tracking of the local references generated in the upper layer, the Nussbaum-type function-based technique is combined with internal model principle. With the proposed two-layer distributed hierarchical controller, the leader-following output consensus is achieved. The obtained result is further extended to the formation control problem. Finally, three numerical examples are provided to demonstrate the effectiveness of the proposed theoretical results.
In this technical note, an impulsive consensus algorithm is proposed for second-order continuous-time multi-agent networks with switching topology. The communication among agents occurs at sampling ...instants based on position only measurements. By using the property of stochastic matrices and algebraic graph theory, some sufficient conditions are obtained to ensure the consensus of the controlled multi-agent network if the communication graph has a spanning tree jointly. A numerical example is given to illustrate the effectiveness of the proposed algorithm.
In this article, the controllability is investigated for nonlinear impulsive and switching systems with input delay. Using the fixed point method, two controllability conditions are developed for ...such systems under different nonlinear constraints. First, the Lipschitz nonlinear condition is considered. A control mapping is constructed based on the input matrix condition, and a nonlinear operator is introduced to convert the controllability into the existence of a fixed point. A sufficient controllability criterion is obtained under the Banach's contraction mapping principle. Second, a linear growth condition is imposed on the nonlinearity. A switched control mapping is constructed using the inverse of controllability matrix, and a corresponding nonlinear operator is introduced. An alternative controllability condition is then developed by resorting to the Rothe's fixed point theorem. It is shown that the system controllability can be influenced by the impulsive and switching factors, beyond the delayed part and the nonlinearity. Two numerical examples are given to verify the theory.
A new kind of high‐performance asymmetric supercapacitor is designed with pyrolyzed bacterial cellulose (p‐BC)‐coated MnO2 as a positive electrode material and nitrogen‐doped p‐BC as a negative ...electrode material via an easy, efficient, large‐scale, and green fabrication approach. The optimal asymmetric device possesses an excellent supercapacitive behavior with quite high energy and power density.
Observer-based dynamic event-triggered semiglobal bipartite consensus (SGBC) is investigated for linear multi-agent systems (MASs) with input saturation under a competitive network. Based on the ...estimated relative information and low-gain feedback technology, distributed dynamic event-triggered control (DETC) protocols are proposed for solving the observer-based SGBC problems for MASs under a fixed topology and a jointly connected topology, respectively. It is turned out that the SGBC of MASs can be achieved under the proposed protocols. By using gauge transformation and the Lyapunov theory, the bipartite consensus conditions are obtained. Moreover, Zeno behaviors will be excluded. Finally, two simulation examples are presented to verify the theoretical results efficiently.
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