This paper discusses the design of resilient and event-triggered control for linear aperiodic sampled-data systems.The stability and stabilization problem of the aperiodic sampled-data systems under a dynamic event-tr...This paper discusses the design of resilient and event-triggered control for linear aperiodic sampled-data systems.The stability and stabilization problem of the aperiodic sampled-data systems under a dynamic event-triggered scheme and against a stochastic deception attack is addressed in a novel looped-functional framework.A quadratic event-triggered scheme with a discrete-time dynamic variable is proposed in which the system states are only evaluated at aperiodic sampling instants so that the Zeno phenomenon can be avoided consequently.The system is assumed to be intruded by a deception attack signal which is determined by a Bernoulli random variable.Our objective in this paper is to derive the stability conditions firstly and then provide the resilient and event-triggered controller design for the aperiodic sampled-data system.With a certain H∞attack and the control updates can be obviously reduced by the proposed dynamic event-triggered scheme,which means the system performance,the limited communication resources,and the system security can be well balanced in our design.Finally,the validity and effectiveness of the proposed method is demonstrated by the simulations.展开更多
Over the past decades,photonics has transformed many areas in both fundamental research and practical applications.In particular,we can manipulate light in a desired and prescribed manner by rationally designed subwav...Over the past decades,photonics has transformed many areas in both fundamental research and practical applications.In particular,we can manipulate light in a desired and prescribed manner by rationally designed subwavelength structures.However,constructing complex photonic structures and devices is still a time-consuming process,even for experienced researchers.As a subset of artificial intelligence,artificial neural networks serve as one potential solution to bypass the complicated design process,enabling us to directly predict the optical responses of photonic structures or perform the inverse design with high efficiency and accuracy.In this review,we will introduce several commonly used neural networks and highlight their applications in the design process of various optical structures and devices,particularly those in recent experimental works.We will also comment on the future directions to inspire researchers from different disciplines to collectively advance this emerging research field.展开更多
The oxygen evolution reaction(OER)electrocatalysts,which can keep active for a long time in acidic media,are of great significance to proton exchange membrane water electrolyzers.Here,Ru-Co_(3)O_(4)electrocatalysts wi...The oxygen evolution reaction(OER)electrocatalysts,which can keep active for a long time in acidic media,are of great significance to proton exchange membrane water electrolyzers.Here,Ru-Co_(3)O_(4)electrocatalysts with transition metal oxide Co_(3)O_(4)as matrix and the noble metal Ru as doping element have been prepared through an ion exchange–pyrolysis process mediated by metal-organic framework,in which Ru atoms occupy the octahedral sites of Co_(3)O_(4).Experimental and theoretical studies show that introduced Ru atoms have a passivation effect on lattice oxygen.The strong coupling between Ru and O causes a negative shift in the energy position of the O p-band centers.Therefore,the bonding activity of oxygen in the adsorbed state to the lattice oxygen is greatly passivated during the OER process,thus improving the stability of matrix material.In addition,benefiting from the modulating effect of the introduced Ru atoms on the metal active sites,the thermodynamic and kinetic barriers have been significantly reduced,which greatly enhances both the catalytic stability and reaction efficiency of Co_(3)O_(4).展开更多
The alternative working modes and flexible working states are the outstanding features of an adaptive cycle engine, with a proper control schedule design being the only way to exploit the performance of such an engine...The alternative working modes and flexible working states are the outstanding features of an adaptive cycle engine, with a proper control schedule design being the only way to exploit the performance of such an engine. However, unreasonable design in the control schedule causes not only performance deterioration but also serious aerodynamic stability problems. Thus, in this work,a hybrid optimization method that automatically chooses the working modes and identifies the optimal and smooth control schedules is proposed, by combining the differential evolution algorithm and the Latin hypercube sampling method. The control schedule architecture does not only optimize the engine steady-state performance under different working modes but also solves the control-schedule discontinuity problem, especially during mode transition. The optimal control schedules are continuous and almost monotonic, and hence are strongly suitable for a control system, and are designed for two different working conditions, i.e., supersonic and subsonic throttling,which proves that the proposed hybrid method applies to various working conditions. The evaluation demonstrates that the proposed control method optimizes the engine performance, the surge margin of the compression components, and the range of the thrust during throttling.展开更多
基金supported in part by the China Scholarship Council(No.202206030132)the European Union-NextGenerationEU。
文摘This paper discusses the design of resilient and event-triggered control for linear aperiodic sampled-data systems.The stability and stabilization problem of the aperiodic sampled-data systems under a dynamic event-triggered scheme and against a stochastic deception attack is addressed in a novel looped-functional framework.A quadratic event-triggered scheme with a discrete-time dynamic variable is proposed in which the system states are only evaluated at aperiodic sampling instants so that the Zeno phenomenon can be avoided consequently.The system is assumed to be intruded by a deception attack signal which is determined by a Bernoulli random variable.Our objective in this paper is to derive the stability conditions firstly and then provide the resilient and event-triggered controller design for the aperiodic sampled-data system.With a certain H∞attack and the control updates can be obviously reduced by the proposed dynamic event-triggered scheme,which means the system performance,the limited communication resources,and the system security can be well balanced in our design.Finally,the validity and effectiveness of the proposed method is demonstrated by the simulations.
文摘Over the past decades,photonics has transformed many areas in both fundamental research and practical applications.In particular,we can manipulate light in a desired and prescribed manner by rationally designed subwavelength structures.However,constructing complex photonic structures and devices is still a time-consuming process,even for experienced researchers.As a subset of artificial intelligence,artificial neural networks serve as one potential solution to bypass the complicated design process,enabling us to directly predict the optical responses of photonic structures or perform the inverse design with high efficiency and accuracy.In this review,we will introduce several commonly used neural networks and highlight their applications in the design process of various optical structures and devices,particularly those in recent experimental works.We will also comment on the future directions to inspire researchers from different disciplines to collectively advance this emerging research field.
基金the National Natural Science Foundation of China(Nos.12025503,U23B2072,and 12105208)。
文摘The oxygen evolution reaction(OER)electrocatalysts,which can keep active for a long time in acidic media,are of great significance to proton exchange membrane water electrolyzers.Here,Ru-Co_(3)O_(4)electrocatalysts with transition metal oxide Co_(3)O_(4)as matrix and the noble metal Ru as doping element have been prepared through an ion exchange–pyrolysis process mediated by metal-organic framework,in which Ru atoms occupy the octahedral sites of Co_(3)O_(4).Experimental and theoretical studies show that introduced Ru atoms have a passivation effect on lattice oxygen.The strong coupling between Ru and O causes a negative shift in the energy position of the O p-band centers.Therefore,the bonding activity of oxygen in the adsorbed state to the lattice oxygen is greatly passivated during the OER process,thus improving the stability of matrix material.In addition,benefiting from the modulating effect of the introduced Ru atoms on the metal active sites,the thermodynamic and kinetic barriers have been significantly reduced,which greatly enhances both the catalytic stability and reaction efficiency of Co_(3)O_(4).
基金funded by National Nature Science Foundation of China(Nos.51776010 and 91860205)supported by the Academic Excellence Foundation of BUAA for PhD Students,China。
文摘The alternative working modes and flexible working states are the outstanding features of an adaptive cycle engine, with a proper control schedule design being the only way to exploit the performance of such an engine. However, unreasonable design in the control schedule causes not only performance deterioration but also serious aerodynamic stability problems. Thus, in this work,a hybrid optimization method that automatically chooses the working modes and identifies the optimal and smooth control schedules is proposed, by combining the differential evolution algorithm and the Latin hypercube sampling method. The control schedule architecture does not only optimize the engine steady-state performance under different working modes but also solves the control-schedule discontinuity problem, especially during mode transition. The optimal control schedules are continuous and almost monotonic, and hence are strongly suitable for a control system, and are designed for two different working conditions, i.e., supersonic and subsonic throttling,which proves that the proposed hybrid method applies to various working conditions. The evaluation demonstrates that the proposed control method optimizes the engine performance, the surge margin of the compression components, and the range of the thrust during throttling.
