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This paper investigates the finite-time leader-following consensus problem for multi-agent systems with switching topologies. First of all, consider the characteristic of failures, a failure distribution model which is more in line with the actual situation is established, and a semi-Markov chain is used to describe the topology switching of the multi-agent system, in which the transfer rate is time-varying. Secondly, based on the past state information, a topology-dependent consensus protocol is established, then the fault-tolerant consensus problem of leader-following multi-agent is transformed into the issue of system stability, according to the mode-dependent Lyapunov function and the finite time stochastic theorem, the sufficient conditions for the stability of the closed-loop system and the constraints of average residence time are obtained. In addition, an initial-state based $ {H_\infty } $ H ∞ performance index is proposed to reduce the influence of zero initial conditions on the system. Finally, a numerical example is provided to show the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

This article investigates the output fault‐tolerant consensus problem for multi‐agent systems with switching topology and deception attacks. In order to reduce the effects of switching topology, the differences between topologies can be modeled as topology uncertainties. In practice, the deception attack may occur in a random way and assumed to satisfy Bernoulli distributions. The purpose of this research is to design an output fault‐tolerant controller such that, in the presence of switching topology, actuator faults, and deception attacks, the finite‐horizon output fault‐tolerant consensus can be achieved under a prespecified H∞$$ {H}_{\infty } $$ performance. An initial‐state‐based performance requirement is constructed, and this bypasses the need for the zero initial condition in the conventional H∞$$ {H}_{\infty } $$ theory. After this, the controller gains are computed by employing an iterative linear matrix inequality scheme. Finally, a numerical example is provided to show the effectiveness of the proposed methods. [ABSTRACT FROM AUTHOR]

Summary: This article studies a kind of asynchronous fault‐tolerant control problem for stochastic systems (Markov jump systems, MJSs) with multiple‐types of actuator failures. Both the loss of effectiveness and stuck fault of actuator are taken into consideration in a unified actuator failures model. The asynchronization phenomenon between the controller and the original system is described by a hidden Markov model. By coupling the unknown stuck fault of actuator and the external disturbances together, the stuck fault and disturbance can be estimated simultaneously. After this, a fault‐tolerant controller based on the estimated values is designed further to automatically compensate for the faults while preserving the uniformly ultimate boundedness of the solutions. Moreover, a mode‐dependent adaptive event‐triggered mechanism is introduced to limit the number of packets sent on the network. Finally, a numerical example is employed to illustrate the effectiveness of the proposed design scheme. [ABSTRACT FROM AUTHOR]

Summary: In this paper, mixed passive / H∞ hybrid controllers are designed for a delayed Markovian jump system with actuator constraints and alarm signal. The actuator constraints include the unknown actuator bias failure and the actuator partial failure, and the controllers are switched by using alarm signals. First, a sufficient condition for mixed passive / H∞ performance of the closed‐loop system is constructed, and robust controllers and fault‐tolerant controllers are designed, respectively. Then, mixed passive / H∞ observers are presented to ensure that the actuator bias failure is well estimated. Next, an alarm system is proposed by designing multiple thresholds to avoid false alarm, and this system is used to invoke suitable controllers and determine whether to remove the estimated value of actuator bias failure. Finally, two numerical examples are given to illustrate the effectiveness of the method. [ABSTRACT FROM AUTHOR]

This paper investigates the problem of non-fragile H ∞ fault-tolerant course-keeping control (NFC) for uncertain unmanned surface vehicles (UUSV) with rudder failures. Firstly, due to the inevitable parameter perturbations in practice, the unmanned surface vehicles (USV) is modeled as a kind of uncertain Nomoto model, and an uncertain second-order under-damped system is used to describe the rudder system. Next, considering the distribution characteristic of failures, a distribution-dependent stochastic failure model is established and incorporated into the controller design. In order to investigate the fragile problems of the controller, a new non-fragile fault-tolerant scheme is given against multiplicative and additive controller gain perturbations. Finally, the effectiveness of the proposed methods is verified via two numerical examples. • A novel non-fragile H ∞ fault-tolerant course-keeping control for uncertain unmanned surface vehicles(USV) with rudder failures is proposed. • A uncertain Nomoto model and a uncertain second-order underdamped system are used to describe the USV system and rudder system respectively. • Based on the distribution characteristic of failures, a distribution-dependent stochastic failure model is established. [ABSTRACT FROM AUTHOR]

In this study, the synchronisation problem of bilateral teleoperation systems with time‐delay and actuator faults is considered. First, the error dynamic system with actuator faults is modelled as a time‐delay system with disturbance, and a fuzzy disturbance observer (FDO) is designed to estimate the unknown non‐linear disturbance. Moreover, an FDO‐based robust controller is provided for the master robot and a reliable controller is designed for the slave robot, respectively. Next, a sufficient condition is given to ensure the tracking error; the disturbance observation error and the parameter error are uniformly ultimate bounded. Finally, a numerical example is shown to illustrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

This paper investigates the problem of exponential synchronization of discrete-time neural networks with mixed time delays, actuator saturation and failures. Meanwhile, the unreliable communication links are considered between the neural networks, and such unreliable links are modeled as stochastic missing data satisfying Bernoulli distributions. In order to show the relationships between actuator constraints, unreliable communication link and mixed delay neural networks, by using Lyapunov functional approach, a missing data probability dependent exponential synchronization criterion is given. Then, based on such criterion, a reliable controller is designed to ensure that the neural networks are exponentially synchronized in the mean square. Finally, a numerical example is provided to illustrate the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

The stability and stabilisation problems for a series of continuous stochastic singular systems with multiple time-varying delays are studied in this paper. First, a useful lemma is proposed and a delay-distribution-dependent Lyapunov functional is constructed. Then, a novel delay-distribution-dependent condition is given to ensure the unforced stochastic singular systems to be regular and impulse-free. The mean-square exponential stability of the whole system is guaranteed under the proposed lemma. As a result, a suitable feedback controller is designed via strict linear matrix inequality such that the system's stabilisation problem is guaranteed. Finally, numerical examples are illustrated to show the proposed result are less conservative than the existing ones and the potential of such technology. [ABSTRACT FROM AUTHOR]

In this paper, the mean-square exponential stability problem for discrete-time recurrent neural networks with time-varying discrete and distributed delays is investigated. Considering the delay distributions, a novel class of Lyapunov functional is introduced. By exploiting all possible information in mixed time delays, a sufficient condition for the whole system to be mean-square exponentially stable is given. Numerical examples are proposed to illustrate the effectiveness of the method, and show that by using the approach in this paper, the obtained results are less conservative than the existing ones. [ABSTRACT FROM AUTHOR]

A new stochastic switched linear model is established to describe the Zigbee-based wireless networked control system (WNCS) with both network-induced delay and packet dropout. The network-induced delay can be less or longer than one sampling period. A sufficient condition is presented for the exponentially mean square stability of the closed-loop WNCS, and corresponding state feedback controller is designed by using the augmenting technique and multi-Lyapunov approach. Then, combined with carrier sense multiple access with collision avoidance (CSMA-CA) algorithm, a method is given to choose proper parameter values. Finally, a numerical example is provided to demonstrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

The problem of robust stabilisation for uncertain discrete singular systems with time-varying delay is discussed in this article. First, a new delay-distribution-dependent Lyapunov function is established. Then, sufficient conditions are proposed for guaranteeing that the uncertain discrete singular system with time-varying delay has the properties of regularity, causality and stability. Finally, a suitable robust state feedback controller is designed by linear matrix inequality. Numerical examples illustrate that the results derived from the proposed method are less conservative than the existing ones. [ABSTRACT FROM AUTHOR]

This paper is concerned with the stability analysis problem for uncertain stochastic discrete-time recurrent neural networks with time-varying delay. By using linear matrix inequality method and discrete Jensen inequality, a new Lyapunov–Krasovskii function is established to derive sufficient condition for globally asymptotical stability in mean square of the recurrent neural networks with stochastic disturbance. As an extension, we further consider the stability analysis problem for the same class of neural networks but with uncertainty. It is shown that the newly obtained result is less conservative than the existing ones when the described system is without disturbance and uncertainty. Meanwhile, the computational complexity is reduced since less variable is involved. Two numerical examples are presented to illustrate the effectiveness and the benefits of the proposed method. [ABSTRACT FROM AUTHOR]

The objective of this paper is to further improve the method of treating hemangioma with the copper needle and to standardize this method. The CHT-5302/MP copper needle therapeutic instrument has been used in a number of assorted cases. A review of 180 hemangioma cases treated by this instrument verifies that it can offer sufficient electricity for clinical use. This shows that the new treatment method offers a reliable, effective means for the treatment of high- or low-flow vascular malformations and hemangiomas. As there are no complications, it is better than previous treatments for hemangioma. It can offer an effective therapy for patients who previously could not be treated or who might require excision of limbs. [ABSTRACT FROM AUTHOR]

Background: Chronic hepatitis B virus (HBV) infection-reduced liver functions are associated with intestinal microbial community dissimilarity. This study aimed to investigate the microbial community dissimilarity in patients with different grades of HBV-related liver cirrhosis. Results: Serum endotoxin was increased with Child–Pugh (CP) class (A, B, and C). Veillonellaceae and Lachnospiraceae families were reduced in patients compared with controls. Megamonas and Veillonella genus was reduced and increased in patients compared with controls, respectively, especially in CPB and CPC groups. Correlation analysis showed that endotoxin content was significantly correlated with alcohol consumption (95% CI 0.100, 0.493), CP class (95% CI 0.289, 0.687) and Lachnospiraceae family level (95% CI − 0.539, − 0.122). Firmicutes/Bacteroidetes ratio was correlated with the level of Lachnospiraceae family (95% CI 0.013, 0.481), Veillonellaceae family (95% CI 0.284, 0.696), Megamonas genus (95% CI 0.101, 0.518) and Veillonella genus (95% CI 0.134, 0.545). All aforementioned bacteria were independent risk or protective factors for hepatitis. Alcohol consumption changed microbial community. Conclusions: Our study demonstrated that elevated Firmicutes/Bacteroidetes ratio, reduced Megamonas genus level and increased Veillonella genus level were indicators for HBV-related liver cirrhosis. Alcohol-related pathogenesis was associated with the changed microbial community. [ABSTRACT FROM AUTHOR]