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[Display omitted] • Prepared ZIF-67/CoFe-LDH has excellent catalytic performance. • DFT demonstrated that oxygen vacancies mediated free radical and non-free radical pathways. • The role of reactive oxygen species in ZIF-67/CoFe-LDH/PMS system was studied. • The SMX degradation pathway was analyzed and the biotoxicity of the degradation intermediates was estimated. Herein, a novel rich oxygen vacancy (Ov) cobalt-iron hydrotalcite composite cobalt metal–organic framework material (ZIF-67/CoFe-LDH) was prepared by simple urea water and heat reduction approach and utilized for the peroxymonosulfate (PMS) system to remove sulfamethoxazole (SMX). 95 ± 1.32 % SMX (20 mg/L) was able to degraded in 20 min with TOC removal of 53 ± 1.56 % in ZIF-67/CoFe-LDH/PMS system. The system maintained a fantastic catalytic capability with wide pH range (3–9) and common interfering substances (Cl−, NO 3 −, CO 3 2−, PO 4 2− and humic acid (HA)), and the degradation efficiency could even remain 80.2 ± 1.48 % at the fifth cycle. Meanwhile, the applicability and feasibility of the catalysts for practical water treatment was verified by the degradation effects of SMX in different water environments and several other typical pollutants. Co and Fe bimetallic active centers synergistically activate PMS, and density functional theory (DFT) predicted adsorption energy about Ov in ZIF-67/CoFe-LDH for PMS was 1.335 eV, and O O bond length of PMS was stretched to 1.826 Å. As a result, PMS was more easily activated and broken, which accelerated the singlet oxygen (1O 2), sulfate radical (SO 4 •−), high-valent metals and other reactive oxygen species (ROS). Radical and non-radical jointly degrading the pollutants improved the catalytic effect. Finally, SMX degradation intermediates were analyzed to explain the degradation pathway and their biotoxicity was also evaluated. This paper provides a new research perspective of oxygen vacancy activating PMS to degrade pollutants. [ABSTRACT FROM AUTHOR]

Based on the previous research on the energy absorption of foam metal materials with different structures, a composite blast-resistant energy-absorbing material with a flexible core layer was designed. The material is composed of three different fiber materials (carbon fiber, aramid fiber, and glass fiber) as the core layer and foamed iron–nickel metal as the front and rear panels. The energy absorption characteristics were tested using a self-built gas explosion tube network experimental platform, and the energy absorption effects of different combinations of blast-resistant materials were analyzed. The purpose of this paper is to evaluate the performance of blast-resistant materials designed with flexible fiber core layers. The experimental results show that the composite structure blast-resistant material with a flexible core layer has higher energy absorption performance. The work performed in this paper shows that the use of flexible core layer materials has great research potential and engineering research value for improving energy absorption performance, reducing the mass of blast-resistant materials, and reducing production costs. It also provides thoughts for the research of biomimetic energy-absorbing materials. [ABSTRACT FROM AUTHOR]

Combining the three-phase foam and simulated sea mud particle (SM-P: simulated sea mud particle) containing inert substances (SMTP: simulated sea mud three-phase foam) to engineer a new three-phase foam fire extinguishing material was a viable strategy to solve the problem of coal mine spontaneous combustion prevention and insufficient stability of mine fire extinguishing materials. Herein, based on constant temperature heating table and simulated coal spontaneous combustion fire extinguishing device, the experiments were conducted to evaluate the material properties. As expected, the SMTP-20 exhibited excellent stability (73.00 mins at 40 °C), which was 2.19 times that of ordinary three-phase foam (34.33 mins at 40 °C). The introduction of SM-P can also effectively reduce the thermal decomposition of powdered coal, the corresponding temperature of thermal decomposition peak value of raw coal was delayed 17.78 °C. The SMTP-20 could construct a thin fibrous-like foam layer with SM-P to cover the surface of burning coal and effectively seal cracks in the coal from oxygen contact, thereby preventing coal further oxidation. This work not only offers a new three-phase foam with outstanding performance, but also unravels a strategy for preparing three-phase foam with high stability and good fire extinguishing effect. [ABSTRACT FROM AUTHOR]

This paper considers a distributed constrained optimization problem over a multi-agent network in the non-Euclidean sense. The gossip protocol is adopted to relieve the communication burden, which also adapts to the constantly changing topology of the network. Based on this idea, a gossip-based distributed stochastic mirror descent (GB-DSMD) algorithm is proposed to handle the problem under consideration. The performances of GB-DSMD algorithms with constant and diminishing step sizes are analyzed, respectively. When the step size is constant, the error bound between the optimal function value and the expected function value corresponding to the average iteration output of the algorithm is derived. While for the case of the diminishing step size, it is proved that the output of the algorithm uniformly approaches to the optimal value with probability 1. Finally, as a numerical example, the distributed logistic regression is reported to demonstrate the effectiveness of the GB-DSMD algorithm. • A Gossip-Based Distributed Stochastic Mirror Descent (GB-DSMD) algorithm is proposed. • In the proposed algorithm, appropriate step-size can be chosen by each agent based on local information. • The impact of two different step sizes on the performance of GB-DSMD algorithm is analyzed. [ABSTRACT FROM AUTHOR]

This paper investigates the exponential mixed H∞/L2-L∞\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\mathcal {H} _{\infty }/\mathcal {L}_{2}-\mathcal {L}_{\infty }$$\end{document} state estimation for Markov switching memristive neural networks (MNNs) with time-varying delays. First, in addition to Markov switching parameters, the random variables that obeys Bernoulli distribution are also involved in the MNN model, and thus the considered system model is much more general. Second, the solution in Filippov’s sense is used to transform the Markov switching MNNs into a stochastic system with interval parameters. Third, the reciprocally convex combination technique and an appropriate Lyapunov-Krasovskii functional containing multiple integrals are used to derive less conservative conditions ensuring the existence of the desired state estimators. Finally, a numerical example is provided to show the validity of the proposed method. [ABSTRACT FROM AUTHOR]

This article investigates the issue of neuro-fuzzy-based adaptive dynamic surface control (DSC) for uncertain fractional-order (FO) nonlinear systems in strict-feedback form where input constraint is considered in the systems. In the recursive steps, the neuro-fuzzy network systems are employed to deal with the unknown nonlinear terms existing in systems. Furthermore, based on a DSC scheme, a modified FO filter is constructed to overcome the problem of explosion of complexity caused by the traditional backstepping design. Moreover, according to the FO Lyapunov stability theory, a neuro-fuzzy-based adaptive controller is designed to guarantee all the signals of FO closed-loop systems tend to be bounded. Finally, the three examples are provided to verify the validity and superiority of the presented control scheme. [ABSTRACT FROM AUTHOR]

This paper is concerned with the design of fuzzy controller for networked control systems (NCSs). T-S fuzzy system approach is adopted to study the problem. In account of NCSs, various data missing on both sides of the controller caused by event-triggered scheme, data losses and event-driven controller are involved. For handling this issue, an auxiliary random series method is presented to describe the data transferring in the network. Based on this method, the closed-loop NCSs is constructed and then analyzed via Lyapunov stability theory. Additionally, the probability of random data losses at each instant is supposed to be different which is more practical. For the purpose of obtaining more relaxed stabilization conditions, the fuzzy Lyapunov function obtained on the basis of both plant and controller fuzzy rules is employed. Furthermore, variations of membership functions are taken into account, and consequently, slack matrices are introduced to obtain less conservative result. At last, by considering a cart-damper-spring system, the effectiveness of the proposed method is illustrated. [ABSTRACT FROM AUTHOR]

Summary: Based on a new triggering quantizer, this article studies the design of networked control systems with limited bandwidth. The design algorithm is described by the program flow diagram, which implements the functions of sampling, quantization and triggering strategy. By using a specific random variable, the effects of networked issues are captured, so as to process the design procedure. Because of the nonlinearities induced by networked issues, new methods are developed to analyze the system stability. Specifically, two design methods are proposed in order to simplify the analysis and improve the performance. Finally, simulation examples are presented to verify the proposed methods. [ABSTRACT FROM AUTHOR]

This work focuses on the fault detection for nonlinear networked systems. A fault detection filter is designed to detect the fault signal under the effect of disturbance. The communication channel of the networked system is supposed to be influenced by the limited bandwidth and random data losses. To deal with these, event-triggered scheme and Bernoulli process are employed to describe the problems, respectively. According to the above situation, we employ a formulated random series to describe the input of fuzzy filter. Differential mean value theorem based method is presented to handle the asynchronous membership functions. Synthetically, linear matrix inequality approach is employed to obtain the stability conditions and the filter design process. At last, we verify the performance of this method acting in the simulation example. [ABSTRACT FROM AUTHOR]

A fractional-order integral fuzzy sliding mode control scheme is proposed for a class of uncertain fractional-order nonlinear systems subject to uncertainties and external disturbances. First, in each step, a neuro-fuzzy network system is developed to approximate the uncertain nonlinear function existing in fractional-subsystem and a fractional sliding mode surface is presented. Second, based on the fractional Lyapunov stability theory and the finite-time stability theory, a fractional adaptive backstepping neuro-fuzzy sliding mode controller is designed to drive the state trajectories of fractional-order systems to the prescribed sliding mode surface. Meanwhile, the finite-time stability of the fractional-order closed-loop system is proved. At last, three numerical examples are given to illustrate the effectiveness of the proposed control method. [ABSTRACT FROM AUTHOR]

This paper aims to design a dissipative fuzzy filter for a class of discrete-time nonlinear networked systems. In order to adopt the limited communication links, we employ an event-triggered scheme to reduce the number of transmitted data in the network by preventing the unnecessary ones from releasing. Due to the digital channel, the data to be transmitted should be quantized and a logarithmic quantizer is employed. Then, when the part of released data is transmitted in the network, data losses is captured by a Bernoulli process. Consequently, the uncomplete data sequence is compensated by the buffer and then send to the filter. During this process, a new random series is developed to help constructing the filtering systems. Thus, a novel method is presented to guarantee the filter error system to be dissipative based on the T–S fuzzy model approach. Finally, an example concerned with Henon mapping system is provided to verify the validity of the proposed design method. [ABSTRACT FROM AUTHOR]

In this paper, a fractional-order backstepping dynamic surface control (DSC) method is developed to cope with the stabilization problem for fractional-order nonlinear systems with uncertainties and external disturbances. In each step, a neuro-fuzzy network system is employed to approximate the unknown nonlinear function existing in fractional-order subsystem. Furthermore, a modified fractional-order filter is designed to avoid the problem of explosion of complexity caused by the recursive procedure. Then based on the fractional-order Lyapunov stability theory, the corresponding adaptive backstepping DSC controller is proposed to guarantee the stability of the fractional-order closed-loop systems. Finally, three examples are given in simulation part to demonstrate the validity of the proposed control method. [ABSTRACT FROM AUTHOR]

Abstract This paper is concerned with the output-feedback stabilization problem for a class of singular linear parameter-varying (LPV) systems. The objective is to design a dynamic output-feedback controller such that the resulting closed-loop system is robustly admissible. Different from the classical gain-scheduling techniques, it is assumed in this paper that the scheduling parameters involved in the plant model are not exactly available for the controller. First, a sufficient and necessary condition for the solvability of the underlying stabilization problem is obtained in the form of general parameter-dependent matrix inequalities. Second, an equivalent transformation is developed to convert the general parameter-dependent conditions into parameter-dependent linear matrix inequalities (LMIs). Third, the singular LPV system whose coefficient matrices take a polytopic form is considered, and the finite LMI-based conditions are derived. Finally, an illustrative example is provided to show the effectiveness of the proposed design methods. [ABSTRACT FROM AUTHOR]

Being a promising potential source for natural gas, methane hydrate (MH) is attracting increasing interest due to its great amount and diverse geographic distribution. The formation of MH is significantly influenced by the properties of sediment media such as porosity and permeability. In this study, in order to have a better understanding on the relationship between MH formation behavior and sediment properties, as well as to synthesize representative hydrate samples, MH was formed in six different sets of mixed-size porous media composed of clay, silt and fine sand, with saline water and circulating methane gas to reflect MH formation with free methane flux in marine sediment. The sediment composition, experimental pressure (15 MPa) and temperature (286.2 K) were chosen based on the SH2 drilling site in the Shenhu area in South China Sea. A two-stage growing behavior was observed for all systems. The gas consumption and hydrate formation rate exhibited positive relations with the permeability and porosity of the sediments. Furthermore, hydrates were found to be preferably formed in the bottom layer of the sediment, which could be attributed to the drastic drop of permeability at the early stage of hydrate formation. Lastly, the hydrate formation rate constant was calculated based on the intrinsic kinetic model and found to be a good reflection of the mass transfer properties of different porous media. [ABSTRACT FROM AUTHOR]

• Two bandit algorithms are designed based on the non-Euclidean framework. The Bregman divergence is used as the distance measure in the projection step. • In our algorithms, the potential time delay existing in the feedback process and the limited network resources are taken into account. • The static regret bounds are provided for the ET-DOCO algorithms with delayed bandit feedback. The obtained results show that the two algorithms can ensure a sublinear regret bound if the triggering threshold tends to zero. This paper is concerned with an online distributed convex-constrained optimization problem over a multi-agent network, where the limited network bandwidth and potential feedback delay caused by network communication are considered. To cope with the limited network bandwidth, an event-triggered communication scheme is introduced in information exchange. Then, based on the delayed (i.e., single-point and two-point) bandit feedback, two event-triggered distributed online convex optimization algorithms are developed by utilizing the Bregman divergence in the projection step. Meanwhile, the convergence of the two developed algorithms is analyzed according to the provided static regret bounds achieved by the algorithm. The obtained results show that a sublinear static regret with respect to the time horizon T can be ensured if the triggering threshold gradually approaches zero. In this case, the corresponding order of the regret bounds is also determined by choosing suitable triggering thresholds. Finally, a distributed online regularized linear regression problem is provided as an example to illustrate the effectiveness of the proposed two algorithms. [ABSTRACT FROM AUTHOR]

This paper considers the problem of flocking with connectivity preservation for a class of disturbed nonlinear multi-agent systems. In order to deal with the nonlinearities in the dynamic of all agents, some auxiliary variables are introduced into the state observer for stability analysis. By proposing a bounded potential function and using adaptive theory, a novel output feedback consensus algorithm is developed to guarantee that the states of all agents achieve flocking with connectivity preservation. [ABSTRACT FROM AUTHOR]

This note studies the problem of decay-rate-dependent exponential stability for neutral stochastic delay systems with Markovian jumping parameters. First, by introducing an operator D ( x t , i ) as well as a novel Lyapunov–Krasovskii functional, sufficient conditions for exponential stability of system with a decay rate are obtained. Second, the results are extended to the robust exponential estimates for uncertain neutral stochastic delay systems with Markovian jumping parameters. Finally, numerical examples are provided to show the effectiveness of the proposed results. [ABSTRACT FROM AUTHOR]

[Display omitted] • Carrier type imposed selection pressure on microbial recruitment. • Elastic cubic sponges induced closer cooperation within anammox community. • Carrier type affected nitrogen conversion related enzymes and genes abundances. • Elastic cubic sponges improved biofilm activity, EPS and heme c content. The impacts of carrier type on anammox community assembly, species interactions and nitrogen conversion were studied in this work. It was found that in addition to shared species with higher abundance, different carrier types recruited rare species by imposing selection pressure. Results from co-occurrence networks revealed that carrier type strongly influenced interactions between keystone species inhabiting within anammox biofilm through potentially inducing niche differences. Overall, elastic cubic sponges would lead to closer cooperation between different populations, whereas plastic hollow cylinders would trigger fiercer competition. Meanwhile, the results based on metagenomics sequencing showed carrier type significantly affected nitrogen conversion related genes abundances, and higher reads number was detected on the elastic cubic sponges. The information obtained in this work could provide some valuable information for the selection and optimization of carrier type in the anammox process. [ABSTRACT FROM AUTHOR]

This paper considers the problem of solving distributed online optimization over a network that consists of multiple interacting nodes. Each node in the network is endowed with a sequence of loss functions, each of which is revealed to the node after a decision has been committed. The goal of the network is to minimize the cumulative loss functions of nodes in a distributed fashion, while subject to two types of information constraints, namely, message quantization and bandit feedback. To this end, a quantized distributed online bandit optimization algorithm is proposed by adopting random quantization operation and one-point gradient estimator. We show the convergence of the algorithm by establishing an O (d T 3 / 4) regret bound, where d is the dimension of states and T is the total number of rounds. Finally, an online distributed quadratic programming problem is investigated to validate the theoretical findings of the paper. [ABSTRACT FROM AUTHOR]

This paper is concerned with the problem of reachable set estimation (RSE) for linear systems with time-varying delays and bounded peak inputs. The purpose is to find an ellipsoid that contains the system state in presence of all bounded peak inputs. First, the RSE problem for nominal time-delay systems is studied based on a relaxed Lyapunov-Krasovskii functional which does not require all the involved symmetric matrices to be positive definite. Delay-dependent and delay-rate-dependent conditions for the existence of a desired ellipsoid are obtained. Second, the RSE problem for time-delay systems with time-varying polytopic uncertainties is investigated. Under the assumption that the uncertain parameters are differentiable and their derivatives are bounded by known scalars, parameter-rate-dependent conditions for the existence of a desired ellipsoid are derived by using a parameter-dependent Lyapunov-Krasovskii functional. When the differentiability of the uncertain parameters is not taken into account, a common Lyapunov-Krasovskii functional is employed to tackle the addressed problem, and parameter-rate-independent conditions are presented. All the obtained conditions are given in terms of matrix inequalities, which become linear matrix inequalities when only one non-convex scalar is prescribed. Finally, the reduced conservatism of the obtained results in comparison with recent ones in the literature is shown through numerical examples. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper investigates the tracking control problem for nonlinear networked systems with repeated scalar nonlinearities. A polynomial fuzzy model based approach is employed to model the nonlinear systems. A polynomial fuzzy controller is designed to drive the system states to follow those of a given reference model. Imperfect communication links with two typical phenomenons (i.e., data packet dropout and signal quantization) are taken into account. Sufficient conditions are obtained in terms of sum of squares, which guarantee the stochastic stability and H ∞ performance constraint. Finally, a simulation example is given to illustrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

This article focuses on the resilient fixed-time stabilization of switched neural networks (SNNs) under impulsive deception attacks. A novel theorem for the fixed-time stability of impulsive systems is established by virtue of the comparison principle. Existing fixed-time stability theorems for impulsive systems assume that the impulsive strength is not greater than 1, while the proposed theorem removes this assumption. SNNs subjected to impulsive deception attacks are modeled as impulsive systems. Some sufficient criteria are derived to ensure the stabilization of SNNs in fixed time. The estimation of the upper bound for the settling time is also given. The influence of impulsive attacks on the convergence time is discussed. A numerical example and an application to Chua's circuit system are given to demonstrate the effectiveness of the theoretical results. [ABSTRACT FROM AUTHOR]

[Display omitted] • N-G promoted anammox average nitrogen removal efficiency by 17.57%. • N-G increased anammox biomass from 18.10% to 28.30%. • N-G improved anammox microbial function in terms of "Metabolism". • N-G enriched the genes involved in nitrogen removal to varing degree. • N-G upregulated the genes controlling extracellular polymeric substance secretion. The effect of 50 mg/L nitrogen-doped graphene (N-G) on anammox microbial guild was studied by metagenomics in this paper. The continuous experiment results showed the average NRE improved by 17.57% with N-G addition. The metagenomic analysis revealed N-G significantly increased the relative abundance of dominant AnAOB (Candidatus Kuenenia) from 18.10% to 28.30%. And the FISH assay further manifested N-G promoted the growth of AnAOB biomass. Meanwhile, metagenomics indicated that N-G enriched the abundance of genes (Hzs , Hdh , NosZ , NorB , NirK , NirS and NrfA) involved in nitrogen metabolism to varying degrees. Furthermore, N-G not only improved the microbial functionality in terms of "Metabolism", but markedly upregulated the abundance of c-di-GMP synthesized genes and genes related to quinolone signal molecule, which contributed to more EPS content and better sludge settleability. In brief, this study provided a novel perspective for anammox biomass enrichment, which may be valuable for practical engineering applications of anammox. [ABSTRACT FROM AUTHOR]

SUMMARY This paper is concerned with the reachable set estimation problem for discrete-time linear systems with multiple constant delays and bounded peak inputs. The objective is to check whether there exists a bounded set that contains all the system states under zero initial conditions. First, delay-dependent conditions for the solvability of the addressed problem are derived by employing a novel Lyapunov-Krasovskii functional. The obtained conditions are expressed in terms of matrix inequalities, which are linear when only one scalar variable is fixed. On the basis of these conditions, an ellipsoid containing the reachable set of the considered system is obtained. An approach for determining the smallest ellipsoid is also provided. Second, the approach and results developed in the first stage are generalized to the case of systems with polytopic parameter uncertainties, and delay-dependent conditions are given in the form of relaxed matrix inequalities. Finally, two numerical examples are provided to demonstrate the effectiveness of the proposed methods. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: This paper is concerned with the problem of exponential filter design for linear systems simultaneously with distributed delays, Markovian jumping parameters and norm-bounded parametric uncertainties. The purpose is to design full-order mode-dependent filters such that the filtering error system is not only mean-square robustly exponentially stable with a specified decay rate but also satisfies an performance requirement. First, sufficient conditions for the stability and performance analysis of the filtering error system are derived based on a novel version of mode-dependent Lyapunov–Krasovskii functional. Then, delay-dependent and decay-rate-dependent conditions for the existence of desired filters are obtained in terms of linear matrix inequalities (LMIs). The filter coefficients can be computed by using feasible solutions of the presented LMIs. Finally, a numerical example is provided to demonstrate the effectiveness of the proposed design method. [Copyright &y& Elsevier]

SUMMARY This paper deals with the problems of passivity analysis and passivity-based controller design for Markovian jump systems with both time-varying delays and norm-bounded parametric uncertainties. Firstly, new delay-dependent conditions for the considered system to be passive are obtained by using a mode-dependent Lyapunov functional and by introducing some slack variables. These conditions are expressed by means of LMIs that are easy to check. It is shown through a numerical example that the obtained passivity conditions are less conservative than the existing ones in the literature. Secondly, the passification problem is investigated. On the basis of the obtained passivity conditions, dynamic output-feedback controllers are designed, which ensure that the resulting closed-loop system is passive. The effectiveness of the proposed design method is demonstrated by a numerical example. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper focuses on the problem of dual-channel event-triggered control for positive nonlinear systems. A dual-channel event-triggered transmission scheme is proposed to determine whether the data packets should be released or not. Two 1-norm-based event-trigger conditions are designed for the sensor-controller channel and controller-actuator channel, respectively. The condition of the system remaining positivity with the designed event-trigger conditions and feedback control law is provided. By using the Lyapunov method and matrix decomposition technique, a sufficient criterion ensuring the closed loop system to be asymptotically stable is proposed. For the linearisation purpose, the control gain is delicately decomposed into a nonnegative component and a non-positive component. Zeno behaviour of the designed event-triggered transmission of sampled data packets is further rigorously proved to be excluded. An example of water pollution control system is provided to show the effectiveness of the obtained results. [ABSTRACT FROM AUTHOR]

Abstract: This paper is concerned with the problem of designing filters for a class of nonlinear networked control systems (NCSs) with transmission delays and packet losses. This problem is investigated under the following assumptions: (i) the delay is constant and known, (ii) the packet-loss process is described by a Bernoulli distributed white sequence, and (iii) the probability of the packet-loss process is unknown but bounded. The first two assumptions are well known in the literature of NCSs, while the last one may often arise in practical networks due to modeling or measurement errors. Under the aforementioned assumptions, delay-dependent conditions for the solvability of the addressed problem are presented in terms of linear matrix inequalities. Numerical examples are also included to illustrate the effectiveness of the proposed method. [Copyright &y& Elsevier]

Abstract: This paper is concerned with the passive controller design problem for a class of continuous-time Takagi–Sugeno (T–S) fuzzy systems with both state and input delays. The delays are assumed to be time-varying and differentiable. A notion of very-strict passivity is adopted. The purpose is to design a state-feedback fuzzy controller such that the resulting closed-loop system is very-strictly passive (VSP). Delay-dependent conditions for the solvability of the addressed problem are obtained by applying recently developed techniques for time-delay systems and fuzzy systems. These conditions are expressed by means of strict linear matrix inequalities (LMIs) that can be easily solved. A numerical example and simulation results are provided to demonstrate the effectiveness of the proposed method. [Copyright &y& Elsevier]

Abstract: This paper is concerned with the problem of absolute exponential stability analysis for a class of continuous-time systems with sector-bounded nonlinearities and interval time-varying delays. Absolute exponential stability criteria, which depend not only on the delay range but also on the decay rate, are derived by using a novel Lyapunov functional. These criteria are expressed in the form of linear matrix inequalities (LMIs) and they can easily be checked. By solving these LMIs, estimates of the exponential decay rate and decay coefficient are obtained. A numerical example is provided to demonstrate the effectiveness of the proposed method. [Copyright &y& Elsevier]

Abstract: This paper deals with the problem of robust stabilization for uncertain Takagi–Sugeno (T–S) fuzzy systems with constant time delays. The purpose is to design a state-feedback fuzzy controller such that the closed-loop system is robustly exponentially stable with a prescribed decay rate. Sufficient conditions for the solvability of this problem are presented in terms of linear matrix inequalities (LMIs). By using feasible solutions of these LMIs, desired fuzzy controllers are designed and their corresponding exponential estimates are given. In addition, the main results of this paper are explicitly dependent on the decay rate. This enables one to design fuzzy controllers by freely selecting decay rates according to different practical conditions. Two numerical examples are provided finally to demonstrate the effectiveness of the proposed design methods. [Copyright &y& Elsevier]

Abstract: This paper deals with the robust and deconvolution filtering problems for stochastic systems with polytopic uncertainties. The purpose is to design a full-order deconvolution filter such that (i) the deconvolution error system is robustly exponentially mean-square stable with a prescribed decay rate and (ii) an or performance of the deconvolution error system is guaranteed. Based on a homogeneous polynomial parameter-dependent matrix (HPPDM) approach, sufficient conditions for the solvability of these problems are given in terms of linear matrix inequalities (LMIs). Such conditions are dependent on the decay rate, which enables one to design robust deconvolution filters by selecting the decay rates according to different practical conditions. In addition, when these LMIs are feasible, a design procedure of the desired filters is developed and an exponential estimate for the deconvolution error system is given. Finally, two numerical examples are provided to demonstrate the effectiveness of the proposed design methods. [Copyright &y& Elsevier]

Abstract: This paper is concerned with the problem of stability analysis for a class of discrete-time recurrent neural networks with time-varying delays. Under a weak assumption on the activation functions and using a new Lyapunov functional, a delay-dependent condition guaranteeing the global exponential stability of the concerned neural network is obtained in terms of a linear matrix inequality. It is shown that this stability condition is less conservative than some previous ones in the literature. When norm-bounded parameter uncertainties appear in a delayed discrete-time recurrent neural network, a delay-dependent robust exponential stability criterion is also presented. Numerical examples are provided to demonstrate the effectiveness of the proposed method. [Copyright &y& Elsevier]

Abstract: This paper is concerned with the problem of delay-dependent stability analysis for discrete-time systems with interval-like time-varying delays and the problem of stabilization for discrete-time linear systems via time-delayed controllers. The first problem is solved by applying a novel Lyapunov functional, and an improved delay-dependent stability criterion is obtained in terms of a linear matrix inequality. Based on this, a sufficient condition for the solvability of the second problem is presented. The reduced conservatism of the proposed stability result is shown through a numerical example, while the applicability of the time-delayed controller design method is demonstrated by an inverted pendulum system. [Copyright &y& Elsevier]

Abstract: This paper is concerned with the delay-dependent stabilization problem for a class of time-delay stochastic fuzzy systems. The time delays are assumed to appear in both the state and the control input. The purpose is the design of a state-feedback fuzzy controller such that the resulting closed-loop system is asymptotically stable in the mean square. A delay-dependent condition for the solvability of this problem is obtained in terms of relaxed linear matrix inequalities (LMIs). By solving these LMIs, a desired controller can be obtained. Finally, a numerical example is given to demonstrate the effectiveness of the present results. [Copyright &y& Elsevier]

This article considers the delay-dependent H∞ control problem for linear neutral systems with both discrete and distributed delays. The problem we address is to design a state feedback controller such that the resulting closed-loop system is asymptotically stable and satisfies a prescribed H∞ performance level. First, a delay-dependent sufficient condition for the solvability of the problem is obtained in terms of matrix inequalities. Then, by using the cone complementarity linearization approach, an H∞ controller is developed based on the solvability condition. Finally, numerical examples are provided to demonstrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Abstract: This Letter investigates the problem of stability analysis for a class of high-order neural networks with time-varying delays. The delays are bounded but not necessarily differentiable. Based on the Lyapunov stability theory together with the linear matrix inequality (LMI) approach and the use of Halanay inequality, sufficient conditions guaranteeing the global exponential stability of the equilibrium point of the considered neural networks are presented. Two numerical examples are provided to demonstrate the effectiveness of the proposed stability criteria. [Copyright &y& Elsevier]

This paper considers the problem of robust exponential stability for a class of recurrent neural networks with time-varying delays and parameter uncertainties. The time delays are not necessarily differentiable and the uncertainties are assumed to be time-varying but norm-bounded. Sufficient conditions, which guarantee that the concerned uncertain delayed neural network is robustly, globally, exponentially stable for all admissible parameter uncertainties, are obtained under a weak assumption on the neuron activation functions. These conditions are dependent on the size of the time delay and expressed in terms of linear matrix inequalities. Numerical examples are provided to demonstrate the effectiveness and less conservatism of the proposed stability results. [ABSTRACT FROM AUTHOR]

This paper investigates the problem of stability analysis for recurrent neural networks with time-varying delays and polytopic uncertainties. Parameter-dependent Lypaunov functionals are employed to obtain sufficient conditions that guarantee the robust global exponential stability of the equilibrium point of the considered neural network. The derived stability criteria are expressed in terms of a set of relaxed linear matrix inequalities, which can be easily tested by using commercially available software. Two numerical examples are provided to demonstrate the effectiveness of the proposed results. [ABSTRACT FROM AUTHOR]

This article studies the output regulation problem (ORP) for nonlinear systems based on prescribed performance control (PPC). The items with the partial derivative of the virtual controller are combined together by using backstepping, and then the fuzzy logic systems (FLSs) are used to approximate these combined items, so that the designed virtual controller does not have the partial derivative of the previous virtual controllers. Therefore, this method not only reduces the calculation burden in the backstepping method, but also avoids the disadvantages of dynamic surface control (DSC). Finally, a function $\Theta $ is constructed such that the overall performance (dynamic performance and steady-state performance) of the tracking error (OPTE) is constrained by PP functions. The proposed control algorithm ensures that all the signals are semi-globally uniformly ultimately bounded (SGUUB), and the tracking error achieves the PPC. Simulation examples are provided to illustrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Magnetite/reduced graphene oxide nanocomposites (Fe 3 O 4 -rGO NCs) and magnetite nanoparticles (Fe 3 O 4 NPs) were added to enhance biohydrogen (bioH 2) production in dark fermentation. Concentration of supplements from 10 to 100 mg/L was appropriate to enhance bioH 2 production, and inhibition appeared once concentration exceeded 100 mg/L. The best bioH 2 yield was 198.30 mL/g glucose at 100 mg/L Fe 3 O 4 NPs and 225.60 mL/g glucose at 100 mg/L Fe 3 O 4 -rGO NCs, which was 42.97% and 62.65% higher than that in the blank group, respectively. Both Fe 3 O 4 NPs and Fe 3 O 4 -rGO NCs could intensify butyrate-type fermentation and change the hydrogen-producing microorganism cells morphology, but the enhancement effect of Fe 3 O 4 -rGO NCs was superior. Microbial community structure analysis showed that Clostridium-sensu-stricto-1 became more dominant ultimately by Fe 3 O 4 -rGO NCs. [Display omitted] • Fe 3 O 4 -rGO NCs were synthesized to enhance biohydrogen yield. • Fe 3 O 4 -rGO NCs enhanced disproportionation reaction of propionate to butyrate. • Fe 3 O 4 NPs and Fe 3 O 4 -rGO NCs could make the microbial cells longer and thicker. • Fe 3 O 4 -rGO NCs involved in intracellular and extracellular electron transfer. • Fe 3 O 4 -rGO NCs increased the abundance of Clostridium-sensu-stricto-1. [ABSTRACT FROM AUTHOR]