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In this article, classification problems for a class of tensor datasets with a noisy environment are investigated. To address such issues, a novel fuzzy support tensor machine (FSTM) dual model with robustness is established. First, for each input sample in the noisy tensor dataset, we define three kinds of fuzzy membership functions, such as linear, cosine, and exponential forms. In particular, the reconstruction process from one-dimensional (1-D) vector data to third-order tensor data is also derived in the Appendix. Second, the original optimization model of an FSTM on fuzzy membership is designed by constructing the vector pattern of the traditional support vector machine (SVM) models into a tensor pattern. Next, by introducing the Lagrangian multiplier method and tensor-Tucker decomposition method to the original FSTM model, an FSTM dual model without tensor inner product operation is obtained for the first time. Such a dual model with tensor-Tucker decomposition form can avoid conservativeness caused by the vectorization of tensor data in the traditional SVM model. Furthermore, an FSTM classifier is derived by the designed numerical algorithm, and the classification generalization error bound of the FSTM model with a general form is developed. It is worth noting that a linear least-squares FSTM (LLS-FSTM) equation with tensor-Tucker decomposition is also designed in the Appendix to further reduce the slightly time-consuming problem of the solving the dual optimization model FSTM. Finally, two numerical examples are presented to verify the feasibility and validity of the derived FSTM classifier. [ABSTRACT FROM AUTHOR]

In this article, the robust control problem of uncertain nonlinear systems subject to magnitude and rate saturation (MRS) is investigated via active disturbance rejection control. To this purpose, we propose a novel robust controller that involves an improved extended state observer (IESO), a composite loop, and two anti-windup loops. The IESO is designed to estimate the state and the total disturbance, which includes the uncertain dynamics and external disturbance. Compared with the traditional ESO, IESO absorbs an anti-windup loop to ensure accurate estimation under MRS. The convergence analysis of IESO is further carried out to theoretically verify the accurate estimation of IESO. The composite loop is generalized to cancel the total disturbance based on the output of IESO. Moreover, a rate anti-windup loop is designed to attenuate the effect of rate saturation on the estimation/cancellation of total disturbance. An algorithm for anti-windup gains computation is correspondingly established, in order to minimize the effect of external disturbance in terms of $L_{2}$ gain while guaranteeing the local asymptotic stability. Finally, the proposed method is applied to aeroengine, which involves large uncertainty and suffers from disturbance and MRS. The experimental results verify the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

This paper studies the problem of the input-to-state stability for homogeneous hybrid systems with bounded time-varying delays. First, some homogeneous concepts and properties are introduced and applied to hybrid systems with bounded time-varying delays. Furthermore, by using Lyapunov-Razumikhin approach, some sufficient conditions are extended to the hybrid systems to analyze the input-to-state stability, and with the homogeneous assumption, some special results can be obtained. Finally, numerical examples are given to illustrate the applicability and the effectiveness of the proposed results. [ABSTRACT FROM AUTHOR]

Summary: In this article, a novel multidimensional penalty‐free method is proposed for the optimal control problem of switched control systems with path constraints. First, by introducing a Boolean vector, the switched control system and path constraints are transformed into affine forms. Typically, the complementary constrained method and piecewise constant function are used to relax and approximate the Boolean vector. Moreover, numerical methods are used to solve the approximated constrained optimal control problem (COCP), which relies on a discrete grid of the control function by using a piecewise linear function. Furthermore, the approximated COCP of affine control systems is equivalently transformed into a constrained dynamic parameter optimization problem by a refined time‐scaling transformation. Finally, the global convergence of the proposed multidimensional penalty‐free algorithm is proved and the feasibility of the algorithm is verified by numerical examples. [ABSTRACT FROM AUTHOR]

This paper investigates a stabilization problem for linear systems subject to saturation and time-varying delays in the control input, where the delay takes both large and small values in an alternating manner. Based on the delay values, the considered system is described by a switched system including a stabilizable subsystem and an unstabilizable subsystem. By using Lyapunov–Krasovskii functional method, a time-dependent switching rule orchestrating the proposed controllers is established to guarantee the regional stabilization of the closed-loop system. To obtain a domain of attraction as large as possible, an optimization problem is formulated in the form of linear matrix inequalities. Numerical examples and simulations are provided to demonstrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

The stability problem is studied for hybrid systems with delays in this paper. Based on Lyapunov–Razumikhin approach, a novel theorem is presented for such system with the characteristic of homogeneity so that the system is globally preasymptotically stable. In particular, under the homogeneous assumption, we are able to obtain some rather weak conditions compared with general nonhomogeneous hybrid systems in this paper. Finally, two illustrative numerical examples are presented to demonstrate the applicability and the effectiveness of our theorems. [ABSTRACT FROM AUTHOR]

This paper investigates a problem of stability analysis for a class of nonlinear systems with a time-varying delay taking both large and small values in an alternating manner. This problem is a delay-dependent stability analysis one but it shares some features with delay-independent ones. Hence, traditional stability analysis techniques for systems with delay are not applicable. By building upon our previous works, we first introduce the concept of delay-hybrid-dependent stability, which characterizes the delays described above. The considered system is first represented as a system with a switched delay. Then by using switching techniques and Lyapunov–Krasovskii functionals (LKFs), a new stability criterion is developed. Next, in the linear context, it is shown how the needed LKFs can be constructed by developing an original design of LKFs. [ABSTRACT FROM AUTHOR]

This paper investigates gain-scheduled control design for linear systems with time-varying state delays subject to actuator saturation and external disturbance. Assuming the disturbance is peak bounded, a sufficient delay-dependent condition is established to guarantee that a family of level sets, corresponding to a novel parameter-dependent Lyapunov–Krasovskii functional, are nested and invariant to the closed-loop system. The invariant sets are then used to obtain nested reachable sets (ellipsoids) to bound the closed-loop states. A family of continuous controllers are designed based on these nested ellipsoids. The controller with the best performance is selected, each time, based on the closed-loop state vector, while complying with the saturation bound, and the resulting closed-loop system is locally input-to-state stable. All conditions are represented in the form of linear matrix inequalities (LMIs) by the linear spline method. Finally, the benefit of the control method is illustrated by two examples. [ABSTRACT FROM AUTHOR]

The secure operation of electricity generation system (EGS) is essential to the quality of electricity and the security of energy Internet. In order to design secure control strategy for EGS, the behavior and capacity of adversary and possible attack should be studied. From this point of view and considering the actuator saturation and the false-data injection attack in control input channel of EGS, we analyze the behavior and stealthiness of adversary and design stealthy attack strategies in this paper. First, we prove that the magnitude of effective attack signal is smaller than the magnitude of injected attack signal because of actuator saturation. Second, we find that smaller actuator saturation limit makes the adversary easier to be detected. Finally, two stealthy attack strategies are designed for EGS which incorporates a $\chi ^{2}$ attack detector, and the effectiveness of them are illustrated through simulation. [ABSTRACT FROM AUTHOR]

This study is to estimate the bounds for the maximum allowable sampling interval (MASI) and the coarsest quantisation density (CQD) that guarantee the stability of non‐linear systems with multi‐input signals sampled and logarithmic quantised. First of all, hybrid feedback systems are proposed to describe the non‐linear control systems. Then a sufficient condition is provided to ensure that the systems are uniformly globally exponentially stable. A crucial step is to find a novel Lyapunov function to verify the stability conditions in the sense of the hybrid framework. Meanwhile, explicit bounds for the MASI and CQD are obtained to guarantee stability. Furthermore, in the case of no quantisation or no sampling, some special stability criteria can be also obtained. Finally, some examples are given to illustrate the effectiveness of the proposed theorem. [ABSTRACT FROM AUTHOR]

Abstract In this paper, the stability problem for time-varying nonlinear delayed systems is investigated. An infinite-dimensional version of the nested Matrosov function theorem is proposed to conclude uniform global asymptotic stability for time-varying nonlinear delayed systems. Such a stability theorem requires a weak Lyapunov functional and some auxiliary functionals and the upper bounds of the derivatives on these functionals must satisfy some nested conditions. The proposed results can be used to analyze uniform asymptotic stability of time-varying delayed systems where LaSalle's invariance principle cannot be applied and Barbalat's lemma is not sufficient to conclude the uniform attractivity property. An example is given to illustrate the effectiveness of the proposed stability theorem. [ABSTRACT FROM AUTHOR]

The work studies the stability problem of networked control systems (NCSs) exposed to various imperfections, including scheduling protocols, transmission intervals, and delays by using hybrid systems tools. First of all, the above‐mentioned NCSs are converted into hybrid control systems. Then under a weaker assumption, the authors construct a novel Lyapunov function to derive a less conservative sufficient condition for the uniform global asymptotic stability of the systems. Furthermore, they derive useful upper bounds for the maximum allowable transmission interval and maximum allowable delay, which significantly improve the existing results. Finally, some examples are presented to illustrate the effectiveness of the proposed theorem. [ABSTRACT FROM AUTHOR]

Abstract This paper deals with the infinite horizon optimal control problem for deterministic Boolean control networks (BCNs) with average cost. Based on the semi-tensor product of matrices and Jordan decomposition technique, a nested optimality equation for the average infinite horizon problem of BCNs is presented. By resorting to Laurent series expression, a novel policy iteration algorithm, which can find the optimal state feedback controller in finite iteration steps, is proposed. Finally, as a practical application, the optimal intervention problem of Ara operon in E. coil is addressed. [ABSTRACT FROM AUTHOR]

In this work, we investigate the problem of event-triggered stabilization for a class of stochastic nonlinear systems. An event-triggered control (ETC) approach is proposed by introducing an additional internal dynamic variable. The presented event-triggered mechanism (ETM) can guarantee the existence of a positive lower bound on inter-event times (or called inter-execution times). In addition, the presented technique can ensure the second moment asymptotic stability of the closed-loop stochastic nonlinear system. [ABSTRACT FROM AUTHOR]

In this paper, we address the stabilization problem of interconnected systems with input delays. The considered system consists of two coupled subsystems with input delays. Distributed predictor-based controllers are proposed to stabilize such interconnected systems and each controller is independent of the others and does not utilize the state information of other subsystems to predict the state of the corresponding subsystem. We also present a low-pass filter version of the predictor-based controller. In order to analyze the stability of the closed-loop systems, such systems are transformed into partial differential equations (PDE). Under the numerical implementations of the predictor-based controller, exponential stability is asserted for the closed-loop systems and explicit Lyapunov functionals are constructed. Finally, an example is given to show the effectiveness of the distributed predictor-based controller. [ABSTRACT FROM AUTHOR]

We provide a distributed control strategy for each mobile agent in a surveillance network in the plane to cooperatively pursue an evader. The pursuit task is relayed from one agent to another when the evader crosses the boundary of the Voronoi regions divided according to the agents’ positions. The dynamics of the resulted cooperative relay-pursuit network are described by a novel model of impulsive systems. As a result, to guarantee the stability of the closed-loop network system, the controllers’ gains are chosen effectively using the solution of an algebraic Riccati equation. The proof of the stability is based on the construction of a switched Lyapunov function. We also show that the proposed controller is able to deal with delays if some sufficient conditions in the form of a set of linear inequalities are satisfied. A numerical example is provided to validate the performance of the proposed controller. [ABSTRACT FROM AUTHOR]

In this paper, we address the stability problem of hybrid systems with memory, which are newly developed to model hybrid dynamic systems affected by delays. For such systems, stability criteria are developed based on Razumikhin-type conditions, which are usually applied in the delay systems. We prove that the hybrid system with memory is uniformly globally pre-asymptotically stable by small gain theorem. Besides, a relaxed Razumikhin-type stability criterion is also proposed which does not require strict decrease of the Lyapunov–Razumikhin function during jumps. Several examples are given to illustrate the effectiveness and generality of the proposed results. [ABSTRACT FROM AUTHOR]

We consider a class of nonlinear time-varying switched control systems for which stabilizing feedbacks are available. We study the effect of the presence of a delay in the input of switched nonlinear systems with an external disturbance. By contrast with most of the contributions available in the literature, we do not assume that all the subsystems of the switched system we consider are stable when the delay is present. Through a Lyapunov approach, we derive sufficient conditions in terms of size of the delay ensuring the global exponential stability of the switched system. Moreover, under appropriate conditions, the input-to-state stability of the system with respect to an external disturbance is established. [ABSTRACT FROM AUTHOR]

In this paper, we consider a class of globally Lipschitz nonlinear continuous networked control systems (NCS) incorporating large time-varying transmission delays and transmission protocols of communication networks with periodic sampling. To stabilize the NCS, we propose a new predictive control design scheme with plant outputs as the only available data. With uniformly globally exponentially stable (UGES) protocols, input-to-state stability of the entire NCS is ensured by small gain theory. In particular, the predictive controller can compensate transmission delays with any finite upper bound under the constraint that the sampling periods of the plant output and the observer output are small enough as well as the constraint that the predictor is accurate enough. The scheme is applied to a benchmark example to illustrate the effectiveness of our proposed method. [ABSTRACT FROM AUTHOR]

This paper investigates the input-to-state stability for switched nonlinear input delay systems under asynchronous switching. Suppose a feedback control law has been designed such that the nominal closed-loop system is exponentially stable for a certain switching signal, and suppose further that a corresponding Lyapunov function for the nominal closed-loop system is available. In the presence of input delay and asynchronous switching, the system may not be stable under the same switching signal. For this case, we explicitly construct Lyapunov–Krasovskii functionals based on the knowledge of the known Lyapunov function. Then, by using the constructed Lyapunov–Krasovskii functionals, a new switching delay-dependent switching signal satisfying the new mode-dependent average dwell time conditions is provided to guarantee the input-to-state stability of the system with respect to the disturbance under a certain input delay bound. Two examples are given to illustrate the effectiveness of the proposed theory. [ABSTRACT FROM AUTHOR]

This study investigates the input‐to‐state stability issue and the Lyapunov–Krasovskii functional construction for a class of switched non‐linear systems with time‐varying input delay under mode‐dependent average dwell‐time scheme. The authors assume that an exponential stabilising state feedback controller has been predesigned for the nominal system and the Lyapunov function for the nominal closed‐loop system is available. When input delay and disturbance are involved, the closed‐loop system may be unstable under the average dwell time for the nominal system. In allusion to this instance, by introducing a positive definite relaxation matrix and constructing a novel piecewise Lyapunov–Krasovskii functional based on the known Lyapunov function, they provide sufficient conditions and the upper bound of the input delay such that the closed‐loop system is input‐to‐state stable with respect to the disturbance. Finally, numerical examples are given to illustrate the effective of the proposed method. [ABSTRACT FROM AUTHOR]

As an emerging research field, networked control systems have shown the increasing importance and attracted more and more attention in the recent years. The integration of control and communication in networked control systems has made the design and analysis of such systems a great theoretical challenge for conventional control theory. Such an integration also makes the implementation of networked control systems a necessary intermediate step towards the final convergence of control, communication, and computation. We here introduce the basics of networked control systems and then describe the state-of-the-art research in this field. We hope such a brief tutorial can be useful to inspire further development of networked control systems in both theory and potential applications. [ABSTRACT FROM AUTHOR]

This study is concerned with the robust predictive control problem for a class of uncertain networked control systems (NCS) with time‐varying delays and packet dropouts. A networked predictive control (NPC) scheme is proposed to compensate for the effect of time‐varying delays and packet dropouts. The closed‐loop NCS with uncertainties under the networked predictive controller are described as coupled switched control systems. Then by Lyapunov function approach, sufficient conditions are provided to guarantee the robust stability of the system in terms of linear matrix inequalities. As an application, the proposed NPC scheme is applied to DC‐motor control to show the effectiveness of the proposed control scheme. [ABSTRACT FROM AUTHOR]

In this article, we propose a switching anti-windup scheme for the aircraft engine control. The linear engine model with asymmetric saturation is first transformed into a switched system, each subsystem of which is subject to symmetric saturation. A state-dependent switching logic is presented to orchestrate the switching among multiple anti-windup compensators. We then establish the sufficient condition to guarantee the regional stability and $\mathcal {L}_{2}$ performance of the resulting closed-loop system. This condition is less conservative since the non-symmetric nature of the saturation nonlinearity can be fully exploited in the control design. Optimization algorithms are further developed for the anti-windup gain design. The theoretical aspect of the proposed method is analyzed rigorously, and the effectiveness is validated through experiments performed on a semi-physical test bed. [ABSTRACT FROM AUTHOR]

The input-to-state stability (ISS) for a class of networked control systems with random delays and packet dropouts appearing simultaneously in both feedback and forward channels is thoroughly investigated in this paper. A new network predictive controller scheme is introduced in order to compensate the effect of transmission delays and packet dropouts. By making use of the small gain theorem, the stability criteria of the considered new system are derived. The proposed stability conditions are fairly easy to check and considerably less conservative than the existing ones. These criteria reveal that, if the original linear systems are controllable and observable, then, by adopting the proposed networked-predictive-control scheme, the ISS properties can be guaranteed for the overall system despite the effects of networking such as transmission bounded delays, packet dropouts, and possible disturbance inputs. When no disturbance inputs occur, the system stability can be guaranteed for random delays with a certain bound or else for any large constant delays. Results for two illustrative examples are given to validate the proposed control scheme, the second one being a laboratory-scale dc-motor rig. [ABSTRACT FROM PUBLISHER]

The problem of guaranteed cost control for a class of networked control systems possessing uncertainties, network delays, and packet dropouts is solved in this paper. By means of introducing an auxiliary variable, a newly coupled, switched system model is derived first. Then, based on a predictive network control scheme, the conditions for guaranteed control performance of the overall system in terms of linear matrix inequalities are given. Next, a novel control design method, involving convex optimization technique to find solutions for the controllers that vary according to network delays and data-dropouts, is developed. It is shown from theory that the obtained criteria are much less conservative than existing ones. Finally, two illustrative examples, the second one being a laboratory-scale rig, are elaborated on to demonstrate the effectiveness of the proposed design method. Both numerical and simulation results appear favorable to this novel network control system synthesis. [ABSTRACT FROM AUTHOR]

Abstract: This paper studies the stability issue for switched nonlinear systems with input delay and disturbance. It is assumed that for the nominal system an exponential stabilizing controller is predesigned such that the switched system is stable under a certain switching signal, and a piecewise Lyapunov function for the corresponding closed-loop system is known. However, in the presence of input delay and disturbance, the system may be unstable under the same switching signal. For this case, a new Lyapunov–Krasovskii functional is firstly constructed based on the known Lyapunov function. Then, by employing this new functional, a new switching signal satisfying the new average dwell time conditions is constructed to guarantee the input-to-state stability of the system under a certain delay bound. The bound on the average dwell time is closely related to the bound on the input delay. Finally, numerical examples are given to illustrate the effectiveness of the proposed theory. [Copyright &y& Elsevier]

The input-to-state stability problem of a class of nonlinear switched networked control systems subject to time-varying transmission intervals, periodical packet dropouts, and communication constraints is investigated. By adopting the extended input-to-state stability(eISS) protocol and constructing a novel Lyapunov function, the input-to-state stability properties of such systems are discussed. Then, by making use of the small-gain theorem, the maximum allowable transmission interval to guarantee system stability is obtained. A batch reactor is finally considered to demonstrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

In order to reduce the possibility of structural fatigue and increase the lifetime of conveying fluid pipe, transverse vibration must be effectively eliminated. In this work, using parallel nonlinear energy sinks (NESs), a passive vibration controller is proposed to dissipate the vibration energy of the conveying fluid pipe. A high-order model of the conveying fluid pipe-parallel NESs system, in the form of partial differential equation, is derived and then converted into a quadratic form model containing the gradient information of a convex function. Combining the energy disturbance technique and first order convexity characteristic, the exponential stability of the closed-loop system is proved, which addresses the effectiveness of the proposed parallel NESs. Then, numerical simulations are given to verify the theoretical results and to illustrate the advantages of parallel NESs comparing with single NES. Finally, the reliability of the proposed approach is preliminarily verified through experiment. [ABSTRACT FROM AUTHOR]

This paper focuses on a spatially large linear system with a distributed array of sensors, each of which offers partial state measurements. Suppose that each sensor runs a distributed state estimator and they may be suffering either partially or fully manipulated stealthy attacks. A partially manipulated attack can inject data to replace the measurements from an infected sensor. While, a fully manipulated attack can totally control the infected sensor including its computation and transmission. Moreover, an attack on sensor is called stealthy if it produces bounded changes in the detection residue. We will study both the impacts of partially and fully manipulated stealthy attacks on the distributed state estimator. Correspondingly, a distributed state estimation system is called vulnerable if one of its local estimate can be destabilized by a stealthy attack. Considering both static and dynamic systems, we will provide four necessary and sufficient conditions for the vulnerability of static/dynamic system under partially/fully manipulated stealthy attacks. Numerical examples are given to illustrate the theoretical results. [ABSTRACT FROM AUTHOR]

This paper addresses stabilization problem for a class of switched stochastic systems with time delays by using piecewise Lyapunov-Krasovskii functional method. Asynchronous switching means the switching of the controller has a time delay to the switching of the system. We provide a set of Lyapunov-Krasovskii-type sufficient conditions for establishing the mean-square exponential stability. The mean-square exponential stability condition for the resulting closed-loop system is firstly derived by further allowing the Lyapunov-Krasovskii functional to increase during the running time of the active subsystem with the mismatched controller. Then, the corresponding solvability condition for stabilizing controllers is established. Finally, we present an example to show the effectiveness of the developed theory. [ABSTRACT FROM AUTHOR]

Abstract: This paper considers integral input-to-state stability (iISS) for a class of hybrid time-delay systems. Discrete dynamics includes impulsive and switching signals, and continuous dynamics is not necessarily stable. Based on multiple Lyapunov–Krasovskii functionals, a dwell-time bound is explicitly given to guarantee iISS of the hybrid delayed system. Compared with existing results on related problems, the obtained stability criteria can be applied to a larger class of hybrid delayed systems. Moreover, the obtained dwell-time bound is less conservative than existing ones. At last, an example related to networked control systems (NCSs) is provided to illustrate the effectiveness of the proposed result. [Copyright &y& Elsevier]

Abstract: Dominant gain-of-function mutations in proprotein convertase subtilisin kexin type 9 (PCSK9) cause familial hypercholesterolaemia (FH) and result in accelerated atherosclerosis and premature coronary heart disease. It is believed that PCSK9 binds to LDL-receptor (LDLR) protein and prevents its recycling to the cell surface; gain-of-function PCSK9 mutants enhance LDLR degradation. Several new variants of PCSK9 have been identified, but their effect on PCSK9 activity has not been determined. We describe a new procedure for assessing the activity of four putative gain-of-function mutations identified in FH patients (D129N, D374H, N425S, R496W). All four mutant proteins were secreted normally from transfected HEK293T cells. Immortalized lymphocytes from normolipaemic controls were incubated with conditioned medium from transfected cells and cell-surface LDLR protein was determined by FACS. D374H was as potent as D374Y in reducing cell-surface LDLR, while the other three mutations were more potent than wild type, but less so than the D374 mutants; this correlated with total serum cholesterol in the patients. Substitution of different amino acids at 374 showed that aspartate in this position was critical; even glutamate at residue 374 increased LDLR degradation. When the assay was carried out with ARH-negative lymphocytes that are unable to internalise the LDLR, D374Y-PCSK9 was able to reduce cell-surface LDLR by 35%, compared with ∼70% for normal lymphocytes. Thus, PCSK9-mediated LDLR degradation is not entirely dependent on ARH function. We propose a novel ARH-independent pathway for PCSK9 activity on LDLR. [Copyright &y& Elsevier]

Abstract: This paper considers the exponential stability problem for a class of discrete time-varying delay systems with large delay sequences (LDSs). A new method based on a switching technique is presented to solve this problem. A switched delay system, in which one of the discrete subsystems may be unstable, is firstly employed to describe such a system, and then some new concepts about LDSs are introduced. Next, using a novel piecewise Lyapunov functional, explicit delay-dependent conditions are developed to show how long and how frequent the LDSs can be and still maintain the system exponentially stable. Without LDSs, the criterion obtained in this paper includes the established one as a special case. Two numerical examples are given to show the effectiveness of the proposed method. [Copyright &y& Elsevier]

Abstract: In this paper, we study stability and -gain for a class of switched systems with time-varying delays. Sufficient conditions for exponential stability and weighted -gain are developed for a class of switching signals with average dwell time. These conditions are delay-dependent and are given in the form of linear matrix inequalities (LMIs). As a special case of such switching signals, we can obtain exponential stability and normal -gain under arbitrary switching signals. The state decay estimate is explicitly given. Two examples illustrate the effectiveness and applicability of the proposed method. [Copyright &y& Elsevier]

An aggregative game involving double-integrator agents is investigated. In this game, the dynamics of all players are subjected to unknown time-varying disturbances and unmodeled terms, and are also influenced by networked attacks on the communication topology. To seek a Nash equilibrium for such games, a novel distributed robust Nash equilibrium seeking algorithm is proposed and the complete closed-loop system is modeled as a hybrid system using an average dwell-time automaton and a time-ratio monitor to constrain attacks. Then, to analyze stability for the proposed algorithm, a Lyapunov function is constructed and uniform asymptotic stability is obtained under a local Lipschitz assumption on the gradients of the payoff functions. In addition, global uniform asymptotic stability is obtained under a global Lipschitz assumption on the gradients. Finally, an example is used to illustrate the results. [ABSTRACT FROM AUTHOR]

As a crucial and expensive component of the aircraft, it is important to effectively predict its remaining useful life (RUL) so as to reduce maintenance costs and improve maintenance strategies. In this paper, a novel concurrent semi-supervised model is proposed to estimate the RUL of the aero-engine. This semi-supervised model can provide satisfying prediction results with only a small amount of labeled data. And the concurrent structure is designed to improve the stability and accuracy of the prediction. The proposed method is verified on the popular C-MAPSS dataset and is compared with a variety of state-of-the-art approaches. The experimental results demonstrate that the proposed method is effective in the task of remaining useful life prediction. [ABSTRACT FROM AUTHOR]

It is well-known that a phase-locked loop (PLL) technique is widely used in engineering scenarios, recovering and synthesizing the phase and frequency values. The loop filter is the core part of the PLL. This article proposes a class of nonlinear active disturbance rejection loop filters for the PLL. First, we present the detailed nonlinear mathematical model of PLL in consideration of the phase unbalancing, the voltage harmonics, and the voltage offset. Next, based on the model, a class of nonlinear active disturbance rejection loop filters with different nonlinearity degree-of-freedom are proposed in the synchronous reference frame, which can make the PLL in possession of better performance in comparison with that of PLL designed by traditional methods. Moreover, the parameter tuning rules of the nonlinear loop filters are given. Furthermore, hardware-in-the-loop experiments are finished in the dSPACE platform so as to check the real-time performance of the loop filters in more electronic aircraft power grid system scenario. At last, we conclude that the loop filter with the nonlinear generalized integrator extended state observer type2 possesses the best performance among the three loop filters for PLL in this article. [ABSTRACT FROM AUTHOR]

For the speed-tracking control of permanent magnet synchronous motor (PMSM) systems, fast dynamic response and high reference speed require a large transient current to provide sufficient electromagnetic torque. However, the excessive transient current may damage the drive circuit and threaten the system safety. Besides, it is also important to pay attention to the influence of multiple disturbances including system parameter uncertainties and unknown load torque variation. To solve these problems, we propose a nonlinear speed-tracking control approach for uncertain PMSM systems. More specifically, based on the cascade control structure and by introducing auxiliary smooth function, we first develop a nonlinear current-constrained controller (CCC) to guarantee the speed tracking, disturbance rejection, and overcurrent protection simultaneously. In order to improve the robustness of the desired performances, we further implement extended state observer (ESO) techniques to propose an ESO-based CCC (ESO-CCC). Finally, comparative experiments are implemented in a 5.5 kW PMSM platform to verify the performance of the proposed two controllers. [ABSTRACT FROM AUTHOR]

Cell size varies during the cell cycle and in response to external stimuli. This requires the tight coordination, or "scaling," of mRNA and protein quantities with the cell volume in order to maintain biomolecule concentrations and cell density. Evidence in cell populations and single cells indicates that scaling relies on the coordination of mRNA transcription rates with cell size. Here, we use a combination of single-molecule fluorescence in situ hybridization (smFISH), time-lapse microscopy, and mathematical modeling in single fission yeast cells to uncover the precise molecular mechanisms that control transcription rates scaling with cell size. Linear scaling of mRNA quantities is apparent in single fission yeast cells during a normal cell cycle. Transcription of both constitutive and periodic genes is a Poisson process with transcription rates scaling with cell size and without evidence for transcriptional off states. Modeling and experimental data indicate that scaling relies on the coordination of RNA polymerase II (RNAPII) transcription initiation rates with cell size and that RNAPII is a limiting factor. We show using real-time quantitative imaging that size increase is accompanied by a rapid concentration-independent recruitment of RNAPII onto chromatin. Finally, we find that, in multinucleated cells, scaling is set at the level of single nuclei and not the entire cell, making the nucleus a determinant of scaling. Integrating our observations in a mechanistic model of RNAPII-mediated transcription, we propose that scaling of gene expression with cell size is the consequence of competition between genes for limiting RNAPII. • Numbers of constitutive and inducible mRNAs scale with cell size • Coordination of RNAPII initiation rates with cell size underpins scaling • Amounts of DNA-bound RNAPII increase with cell size and are limiting • Transcription of constitutive and periodic mRNAs is a non-bursty Poisson process Messenger RNA numbers scale with cell size to maintain constant concentrations. Using experimental approaches and mathematical models, Sun et al. show that scaling results from the coordination of RNAPII initiation rates with cell size. They propose a model where scaling is the consequence of competition between genes for limiting RNAPII. [ABSTRACT FROM AUTHOR]