Uncontrolled hemorrhage remains the leading cause of death in clinical and emergency care,posing a major threat to human life.To achieve effective bleeding control,many hemostatic materials have emerged.Among them,nat...Uncontrolled hemorrhage remains the leading cause of death in clinical and emergency care,posing a major threat to human life.To achieve effective bleeding control,many hemostatic materials have emerged.Among them,nature-derived biopolymers occupy an important position due to the excellent inherent biocompatibility,biodegradability and bioactivity.Additionally,sponges have been widely used in clinical and daily life because of their rapid blood absorption.Therefore,we provide the overview focusing on the latest advances and smart designs of biopolymer-based hemostatic sponge.Starting from the component,the applications of polysaccharide and polypeptide in hemostasis are systematically introduced,and the unique bioactivities such as antibacterial,antioxidant and immunomodulation are also concerned.From the perspective of sponge structure,different preparation processes can obtain unique physical properties and structures,which will affect the material properties such as hemostasis,antibacterial and tissue repair.Notably,as development frontier,the multifunctions of hemostatic materials is summarized,mainly including enhanced coagulation,antibacterial,avoiding tumor recurrence,promoting tissue repair,and hemorrhage monitoring.Finally,the challenges facing the development of biopolymer-based hemostatic sponges are emphasized,and future directions for in vivo biosafety,emerging materials,multiple application scenarios and translational research are proposed.展开更多
In current memristor-based neuromorphic computing research,several studies face the challenge of realizing only a single function at a time or having isolated functions.This limitation is particularly evident when sim...In current memristor-based neuromorphic computing research,several studies face the challenge of realizing only a single function at a time or having isolated functions.This limitation is particularly evident when simulating biological cognition,as the overall synergy between multiple cognitive functions is difficult to represent.In this work,a high-performance heterojunction memristor is presented at first.The memristor-based neural network and functional circuit are further implemented to realize and integrate multiple cognitive functions.Specifically,the proposed photoelectric memristor has the structure of Ag/ZnO-SnO_(2)/WO_(3-x)/ITO,it exhibits various synaptic behaviors under external modulations,which are characterized by good stability and repeatability.Based on this device,a neural network is built to realize the basic recognition function in biological cognition.The recognition results are translated into different labelled voltage signals and subsequently fed into a memristor-based functional circuit.By leveraging memory characteristics and tunable conductance of the memristor,and controlling the specific circuit functionalities,the input signals are processed to produce different outputs representing various cognitive functions.This methodology allows the realization and integration of recognition,memory,learning,association,relearning,and forgetting into one single system,thereby enabling a more comprehensive and authentic simulation of biological cognition.This work presents a novel memristor and a method for achieving and integrating multiple neuromorphic computing functions within a single system,providing a successful example for achieving complete biological function.展开更多
NXP Semiconductors’ new G2iL and G2iL+EPC Gen 2 chips will enable tags to be turned on or off,be switched into low read range,send tamper alerts or transfer data to microcontrollers.
In this paper,we study normal families of meromorphic functions.By using the idea in[16],we obtain some normality criteria for families of meromorphic functions concerning the wandering multiple functions,which extend...In this paper,we study normal families of meromorphic functions.By using the idea in[16],we obtain some normality criteria for families of meromorphic functions concerning the wandering multiple functions,which extend and improve the well-known Montel's criterion,Bloch-Valiron's theorem,and the related results due to Carathéodory,and Grahl-Nevo et al..展开更多
This paper presents a procedure to develop fragility curves of structures equipped with TMD considering multiple failure functions.The failure criteria considered are maximum inter-story drift ratio as a safety criter...This paper presents a procedure to develop fragility curves of structures equipped with TMD considering multiple failure functions.The failure criteria considered are maximum inter-story drift ratio as a safety criterion,maximum absolute acceleration as a convenience criterion and TMD stroke length.The relationship between intensity measure and responses of the structure was assumed to follow the power-law model,and a regression analysis was used to estimate its properties.A nonlinear eight-story shear building subjected to near-fault earthquakes was used for the numerical studies.Fragility curves using multiple and single failure functions for an uncontrolled structure and a structure equipped with optimal TMDs were developed.Numerical analysis showed that using multiple failure functions led to increasing the fragility when compared with using the single failure function for both the uncontrolled and controlled structures.However,TMDs slightly reduced the seismic fragility and have the capability to improve the reliability of the structure.Also,it was found that the fragility was significantly influenced by the values of the capacity thresholds of both the acceleration of the structure and TMD stroke length,which should be selected by considering the target performance and application of the structure and control device.展开更多
In this paper, both Fritz John and Karush-Kuhn-Tucker necessary optimality conditions are established for a （weakly） LU-efficient solution in the considered nonsmooth multiobjective programming problem with the mult...In this paper, both Fritz John and Karush-Kuhn-Tucker necessary optimality conditions are established for a （weakly） LU-efficient solution in the considered nonsmooth multiobjective programming problem with the multiple interval-objective function. Further, the sufficient optimality conditions for a （weakly） LU-efficient solution and several duality results in Mond-Weir sense are proved under assumptions that the functions constituting the considered nondifferentiable multiobjective programming problem with the multiple interval- objective function are convex.展开更多
Aqueous zinc-ion batteries are a kind of attractive power supply devices due to their high energy, environmental benignity, and intrinsic safety. In recent years, tremendous enthusiasm has been devoted to the function...Aqueous zinc-ion batteries are a kind of attractive power supply devices due to their high energy, environmental benignity, and intrinsic safety. In recent years, tremendous enthusiasm has been devoted to the functionalities of aqueous zinc-ion batteries, aiming to extend their potential applications in multiple dimensions and multiple scales. Here, the latest advances in the design, construction, and performance evaluation of aqueous zinc-ion batteries are summarized. The focus is on various functionalities such as flexibility, self-healing, self-charging, and miniaturization. We also highlight the materials and structures that have been engineered to realize these functionalities. Finally, we offer some general insights into the challenges and chances in such exciting field.展开更多
This paper is devoted to investigating the solutions of refinement equations of the form Ф（x）=∑α∈Z^s α（α）Ф（Mx-α）,x∈R^s,where the vector of functions Ф = （Ф1,… ,Фr）^T is in （L1（R^s））^r, α =（...This paper is devoted to investigating the solutions of refinement equations of the form Ф（x）=∑α∈Z^s α（α）Ф（Mx-α）,x∈R^s,where the vector of functions Ф = （Ф1,… ,Фr）^T is in （L1（R^s））^r, α =（α（α））α∈Z^s is an infinitely supported sequence of r × r matrices called the refinement mask, and M is an s × s integer matrix such that lim n→∞ M^-n =0, with m = detM. Some properties about the solutions of refinement equations axe obtained.展开更多
This paper addresses the cooperative output regulation problem of a class of multi-agent systems （MASs）. Each agent is a switched linear system. We propose an agent-dependent multiple Lyapunov function （MLF） appro...This paper addresses the cooperative output regulation problem of a class of multi-agent systems （MASs）. Each agent is a switched linear system. We propose an agent-dependent multiple Lyapunov function （MLF） approach to design the switching law for each switched agent. The distributed controller for each agent is constructed based on a dynamic compensator. A sufficient condition for the solvability of the output regulation problem of switched agent networks is presented by distributed controllers and agent-dependent multiple Lyapunov function approach. Finally, simulation results demonstrate the effectiveness of our theory.展开更多
The basic principles of the partial and multiple coherence ananlysis and their utilization on vibration source identification are discussed in detail in this paper. The partial coherence analysis is the effective meth...The basic principles of the partial and multiple coherence ananlysis and their utilization on vibration source identification are discussed in detail in this paper. The partial coherence analysis is the effective method of vibration source identification in multiple input single output systems.Formerly, there was not any this kind of function in the signal processor, and there was not any special software too. The software which we developed and used in the 7T 17S signal processor has this function. This software can be used not only for the partial and multiple coherence analysis of signal, but also for the correlation analysis, power spectrum analysis, transfer function analysis et al.We used this software to make the identifcation of the vibration source of the car floor board of electrical measuring vehicle, and to find the main factors which effect the vibration of the car board.The excellent result was obtained. This method can also be used for making the identifications of noise source and other sources.展开更多
The notion of a sort of biorthogonal multiple vector-valued bivariate wavelet packets,which are associated with a quantity dilation matrix,is introduced.The biorthogonality property of the multiple vector-valued wavel...The notion of a sort of biorthogonal multiple vector-valued bivariate wavelet packets,which are associated with a quantity dilation matrix,is introduced.The biorthogonality property of the multiple vector-valued wavelet packets in higher dimensions is studied by means of Fourier transform and integral transform biorthogonality formulas concerning these wavelet packets are obtained.展开更多
[ Objective] The multiple mean generational function （MMGF） method was applied to forecast the annual number of typhoons （TYs） over the Western North Pacific （WNP）. [Method]The method yields a number of predicto...[ Objective] The multiple mean generational function （MMGF） method was applied to forecast the annual number of typhoons （TYs） over the Western North Pacific （WNP）. [Method]The method yields a number of predictors by mean generational function based on the rolling 50- year data of TYs frequency and sunspot number, and was repeated to generate forecasts year after year by optimal subset regression. [ Result] The results showed a reasonably high predictive ability dudng period 2000 -2010, with an average root mean square （RMSE） value of 1.92 and a mean absolute error （MAE） value of 1.64. [ Conclusion] Although the MMGF method needs further validation in the practical operation, it already has strong potential for the improvement of skill at forecasting annual frequency of TYs in the WNP.展开更多
The order of magnitude of multiple Fourier coefficients of complex valued functions of generalized bounded variations like （∧^1,.. .,∧^N）BV^（p） and r-BV, over [0,2π]^ N, are estimated.
This paper considers adaptive event-triggered stabilization for a class of uncertain time-varying nonlinear systems.Remarkably,the systems contain intrinsic time-varying unknown parameters which are allowed to be non-...This paper considers adaptive event-triggered stabilization for a class of uncertain time-varying nonlinear systems.Remarkably,the systems contain intrinsic time-varying unknown parameters which are allowed to be non-differentiable and in turn can be fast-varying.Moreover,the systems admit unknown control directions.To counteract the different uncertainties,more than one compensation mechanism has to be incorporated.However,in the context of event-triggered control,ensuring the effectiveness of these compensation mechanisms under reduced execution necessitates delicate design and analysis.This paper proposes a tight and powerful strategy for adaptive event-triggered control(ETC)by integrating the state-of-the-art adaptive techniques.In particular,the strategy substantially mitigates the conservatism caused by repetitive inequality-based treatments of uncertainties.Specifically,by leveraging the congelation-of-variables method and tuning functions,the conservatism in the treatment of the fast-varying parameters is significantly reduced.With multiple Nussbaum functions employed to handle unknown control directions,a set of dynamic compensations is designed to counteract unknown amplitudes of control coefficients without relying on inequality-based treatments.Moreover,a dedicated dynamic compensation is introduced to deal with the control coefficient coupled with the execution error,based on which a relativethreshold event-triggering mechanism(ETM)is rigorously validated.It turns out that the adaptive event-triggered controller achieves the closed-loop convergence while guaranteeing a uniform lower bound for inter-execution times.Simulation results verify the effectiveness and superiority of the proposed strategy.展开更多
This research focuses on detecting faults in flight vehicles with unstable subsystems operating asynchronously.By accounting for asynchronous switching,a switched model is established,and filters for fault detection(F...This research focuses on detecting faults in flight vehicles with unstable subsystems operating asynchronously.By accounting for asynchronous switching,a switched model is established,and filters for fault detection(FD)in unstable subsystems are developed.The FD challenge is then transformed into an H∞filtering issue.Utilizing the multiple discontinuous Lyapunov function(MDLF)approach and the mode-dependent average dwell time(MDADT)method,sufficient conditions are derived to ensure stability during both fast and slow switching.Furthermore,the existence and solutions for FD filters are provided through linear matrix inequalities(LMIs).The simulation outcomes demonstrated the excellent performance of the developed method in studied cases.展开更多
Based on winter nursery and shuttle breeding, Hainan National Breeding and Multiplication （HNBM）, with off-season breeding and seed production as the essence, has become a national strategic resource. The way of HNB...Based on winter nursery and shuttle breeding, Hainan National Breeding and Multiplication （HNBM）, with off-season breeding and seed production as the essence, has become a national strategic resource. The way of HNBM rising to the national strategy was analyzed through the aspects of technology features, historical characteristics, irreplaceability, function and value hierarchy, and the key problems. As the major achievement of the practice of scientific research and historical selec- tion, HNBM played an irreplaceable role in the climatic conditions, scientific breed- ing, and seed production in disaster relief, protecting the safety of the seed industry and Iocational advantages. Based on the analysis on the functions, values and ex- isted problems of HNBM, the function and value hierarchical structure of HNBM was established through introducing concepts of value engineering, industrial clusters and regional economy. But to fully achieve the industrial clustering development and functional values of HNBM, it needed to solve the key problems existed in top-level planning, experimental bases, system design, hardware construction and ecological security. Some suggestions were put forward in this paper, including setting up key scientific research protection zones, improving the regulations and policies safeguard mechanism and management system of HNBM, drawing up and carrying out the base development planning of HNBM, and striving for financial support from national policies.展开更多
The exponential stabilization problem for finite dimensional switched systems is extended to the infinite dimensional distributed parameter systems in the Hilbert space. Based on the semigroup theory, by applying the ...The exponential stabilization problem for finite dimensional switched systems is extended to the infinite dimensional distributed parameter systems in the Hilbert space. Based on the semigroup theory, by applying the multiple Lyapunov function method, the exponential stabilization conditions are derived. These conditions are given in the form of linear operator inequalities where the decision variables are operators in the Hilbert space; while the stabilization properties depend on the switching rule. Being applied to the two-dimensional heat switched propagation equations with the Dirichlet boundary conditions, these linear operator inequalities are transformed into standard linear matrix inequalities. Finally, two examples are given to illustrate the effectiveness of the proposed results.展开更多
This paper deals with the problem of switching between an open-loop estimator and a close-loop estimator for compensating transmission error and packet dropout of networked control systems. Switching impulse is consid...This paper deals with the problem of switching between an open-loop estimator and a close-loop estimator for compensating transmission error and packet dropout of networked control systems. Switching impulse is considered in order to reduce the error between theory and application, a sufficient condition for exponential stabilization of networked control systems under a given switching rule is presented by multiple Lyapunov-like functions. These results are presented for both continuous-time and discrete-time domains. Controllers are designed by means of linear matrix inequalities. Sim- ulation results show the feasibility and efficiency of the proposed method.展开更多
This paper is concerned with controller synthesis for linear switched systems with actuator saturation. Based on common Lyapunov function technique and multiple-Lyapunov function technique, two methods for designing s...This paper is concerned with controller synthesis for linear switched systems with actuator saturation. Based on common Lyapunov function technique and multiple-Lyapunov function technique, two methods for designing state feedback controller are proposed respectively in terms of linear matrix inequalities for the switched systems with saturation. An approach on enlarging the attractive domain is then investigated, The application of the presented approach is illustrated finally by a numerical example.展开更多
This paper focuses on the H_∞ model reference tracking control for a switched linear parameter-varying(LPV)model representing an aero-engine. The switched LPV aeroengine model is built based on a family of linearized...This paper focuses on the H_∞ model reference tracking control for a switched linear parameter-varying(LPV)model representing an aero-engine. The switched LPV aeroengine model is built based on a family of linearized models.Multiple parameter-dependent Lyapunov functions technique is used to design a tracking control law for the desirable H_∞ tracking performance. A control synthesis condition is formulated in terms of the solvability of a matrix optimization problem.Simulation result on the aero-engine model shows the feasibility and validity of the switching tracking control scheme.展开更多
基金jointly sponsored by Sichuan Science and Tech-nology Program(2024NSFSC0002 and MZGC20240011)“1.3.5”Project for Disciplines of Excellence,West China Hospital,Sichuan University(ZYGD23037)+1 种基金the Frontiers Medical Center,Tianfu Jincheng Laboratory Foundation(TFJC2023010002)the National Natural Science Foundation of China(Grant No.32171351).
文摘Uncontrolled hemorrhage remains the leading cause of death in clinical and emergency care,posing a major threat to human life.To achieve effective bleeding control,many hemostatic materials have emerged.Among them,nature-derived biopolymers occupy an important position due to the excellent inherent biocompatibility,biodegradability and bioactivity.Additionally,sponges have been widely used in clinical and daily life because of their rapid blood absorption.Therefore,we provide the overview focusing on the latest advances and smart designs of biopolymer-based hemostatic sponge.Starting from the component,the applications of polysaccharide and polypeptide in hemostasis are systematically introduced,and the unique bioactivities such as antibacterial,antioxidant and immunomodulation are also concerned.From the perspective of sponge structure,different preparation processes can obtain unique physical properties and structures,which will affect the material properties such as hemostasis,antibacterial and tissue repair.Notably,as development frontier,the multifunctions of hemostatic materials is summarized,mainly including enhanced coagulation,antibacterial,avoiding tumor recurrence,promoting tissue repair,and hemorrhage monitoring.Finally,the challenges facing the development of biopolymer-based hemostatic sponges are emphasized,and future directions for in vivo biosafety,emerging materials,multiple application scenarios and translational research are proposed.
基金supported in part by the Shandong Provincial Natural Science Foundation of China under Grant ZR2023ZD03 and ZR2024QF183in part by the Taishan Scholars Project Special Funds under Grant tsqn202312035.
文摘In current memristor-based neuromorphic computing research,several studies face the challenge of realizing only a single function at a time or having isolated functions.This limitation is particularly evident when simulating biological cognition,as the overall synergy between multiple cognitive functions is difficult to represent.In this work,a high-performance heterojunction memristor is presented at first.The memristor-based neural network and functional circuit are further implemented to realize and integrate multiple cognitive functions.Specifically,the proposed photoelectric memristor has the structure of Ag/ZnO-SnO_(2)/WO_(3-x)/ITO,it exhibits various synaptic behaviors under external modulations,which are characterized by good stability and repeatability.Based on this device,a neural network is built to realize the basic recognition function in biological cognition.The recognition results are translated into different labelled voltage signals and subsequently fed into a memristor-based functional circuit.By leveraging memory characteristics and tunable conductance of the memristor,and controlling the specific circuit functionalities,the input signals are processed to produce different outputs representing various cognitive functions.This methodology allows the realization and integration of recognition,memory,learning,association,relearning,and forgetting into one single system,thereby enabling a more comprehensive and authentic simulation of biological cognition.This work presents a novel memristor and a method for achieving and integrating multiple neuromorphic computing functions within a single system,providing a successful example for achieving complete biological function.
文摘NXP Semiconductors’ new G2iL and G2iL+EPC Gen 2 chips will enable tags to be turned on or off,be switched into low read range,send tamper alerts or transfer data to microcontrollers.
文摘In this paper,we study normal families of meromorphic functions.By using the idea in[16],we obtain some normality criteria for families of meromorphic functions concerning the wandering multiple functions,which extend and improve the well-known Montel's criterion,Bloch-Valiron's theorem,and the related results due to Carathéodory,and Grahl-Nevo et al..
文摘This paper presents a procedure to develop fragility curves of structures equipped with TMD considering multiple failure functions.The failure criteria considered are maximum inter-story drift ratio as a safety criterion,maximum absolute acceleration as a convenience criterion and TMD stroke length.The relationship between intensity measure and responses of the structure was assumed to follow the power-law model,and a regression analysis was used to estimate its properties.A nonlinear eight-story shear building subjected to near-fault earthquakes was used for the numerical studies.Fragility curves using multiple and single failure functions for an uncontrolled structure and a structure equipped with optimal TMDs were developed.Numerical analysis showed that using multiple failure functions led to increasing the fragility when compared with using the single failure function for both the uncontrolled and controlled structures.However,TMDs slightly reduced the seismic fragility and have the capability to improve the reliability of the structure.Also,it was found that the fragility was significantly influenced by the values of the capacity thresholds of both the acceleration of the structure and TMD stroke length,which should be selected by considering the target performance and application of the structure and control device.
文摘In this paper, both Fritz John and Karush-Kuhn-Tucker necessary optimality conditions are established for a （weakly） LU-efficient solution in the considered nonsmooth multiobjective programming problem with the multiple interval-objective function. Further, the sufficient optimality conditions for a （weakly） LU-efficient solution and several duality results in Mond-Weir sense are proved under assumptions that the functions constituting the considered nondifferentiable multiobjective programming problem with the multiple interval- objective function are convex.
基金Sponsored by the Fundamental Research Program of Shanxi Province (Grant No.202103021223019)the Science and Technology Major Project of Shanxi (Grant No. 202101030201022)+1 种基金the National Natural Science Foundation of China (Grant Nos.52172219, 51872192)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (Grant No.19KJA170001)。
文摘Aqueous zinc-ion batteries are a kind of attractive power supply devices due to their high energy, environmental benignity, and intrinsic safety. In recent years, tremendous enthusiasm has been devoted to the functionalities of aqueous zinc-ion batteries, aiming to extend their potential applications in multiple dimensions and multiple scales. Here, the latest advances in the design, construction, and performance evaluation of aqueous zinc-ion batteries are summarized. The focus is on various functionalities such as flexibility, self-healing, self-charging, and miniaturization. We also highlight the materials and structures that have been engineered to realize these functionalities. Finally, we offer some general insights into the challenges and chances in such exciting field.
基金Supported by the National Natural Science Foundation of China (10071071)
文摘This paper is devoted to investigating the solutions of refinement equations of the form Ф（x）=∑α∈Z^s α（α）Ф（Mx-α）,x∈R^s,where the vector of functions Ф = （Ф1,… ,Фr）^T is in （L1（R^s））^r, α =（α（α））α∈Z^s is an infinitely supported sequence of r × r matrices called the refinement mask, and M is an s × s integer matrix such that lim n→∞ M^-n =0, with m = detM. Some properties about the solutions of refinement equations axe obtained.
基金supported by National Natural Science Foundation of China(Nos.61304058 and 61233002)IAPI Fundamental Research Funds(No.2013ZCX03-01)General Project of Scientific Research of the Education Department of Liaoning Province(No.L2015547)
文摘This paper addresses the cooperative output regulation problem of a class of multi-agent systems （MASs）. Each agent is a switched linear system. We propose an agent-dependent multiple Lyapunov function （MLF） approach to design the switching law for each switched agent. The distributed controller for each agent is constructed based on a dynamic compensator. A sufficient condition for the solvability of the output regulation problem of switched agent networks is presented by distributed controllers and agent-dependent multiple Lyapunov function approach. Finally, simulation results demonstrate the effectiveness of our theory.
文摘The basic principles of the partial and multiple coherence ananlysis and their utilization on vibration source identification are discussed in detail in this paper. The partial coherence analysis is the effective method of vibration source identification in multiple input single output systems.Formerly, there was not any this kind of function in the signal processor, and there was not any special software too. The software which we developed and used in the 7T 17S signal processor has this function. This software can be used not only for the partial and multiple coherence analysis of signal, but also for the correlation analysis, power spectrum analysis, transfer function analysis et al.We used this software to make the identifcation of the vibration source of the car floor board of electrical measuring vehicle, and to find the main factors which effect the vibration of the car board.The excellent result was obtained. This method can also be used for making the identifications of noise source and other sources.
基金Supported by Natural Science Foundation of Henan Province（0511013500）
文摘The notion of a sort of biorthogonal multiple vector-valued bivariate wavelet packets,which are associated with a quantity dilation matrix,is introduced.The biorthogonality property of the multiple vector-valued wavelet packets in higher dimensions is studied by means of Fourier transform and integral transform biorthogonality formulas concerning these wavelet packets are obtained.
基金Supported by the Natural Science Fund of Education Department of Anhui Province (KJ2012Z097)
文摘[ Objective] The multiple mean generational function （MMGF） method was applied to forecast the annual number of typhoons （TYs） over the Western North Pacific （WNP）. [Method]The method yields a number of predictors by mean generational function based on the rolling 50- year data of TYs frequency and sunspot number, and was repeated to generate forecasts year after year by optimal subset regression. [ Result] The results showed a reasonably high predictive ability dudng period 2000 -2010, with an average root mean square （RMSE） value of 1.92 and a mean absolute error （MAE） value of 1.64. [ Conclusion] Although the MMGF method needs further validation in the practical operation, it already has strong potential for the improvement of skill at forecasting annual frequency of TYs in the WNP.
文摘The order of magnitude of multiple Fourier coefficients of complex valued functions of generalized bounded variations like （∧^1,.. .,∧^N）BV^（p） and r-BV, over [0,2π]^ N, are estimated.
基金supported in part by the National Natural Science Foundation of China(62033007)the Fundamental Research Program of Shandong Province(ZR2023ZD37).
文摘This paper considers adaptive event-triggered stabilization for a class of uncertain time-varying nonlinear systems.Remarkably,the systems contain intrinsic time-varying unknown parameters which are allowed to be non-differentiable and in turn can be fast-varying.Moreover,the systems admit unknown control directions.To counteract the different uncertainties,more than one compensation mechanism has to be incorporated.However,in the context of event-triggered control,ensuring the effectiveness of these compensation mechanisms under reduced execution necessitates delicate design and analysis.This paper proposes a tight and powerful strategy for adaptive event-triggered control(ETC)by integrating the state-of-the-art adaptive techniques.In particular,the strategy substantially mitigates the conservatism caused by repetitive inequality-based treatments of uncertainties.Specifically,by leveraging the congelation-of-variables method and tuning functions,the conservatism in the treatment of the fast-varying parameters is significantly reduced.With multiple Nussbaum functions employed to handle unknown control directions,a set of dynamic compensations is designed to counteract unknown amplitudes of control coefficients without relying on inequality-based treatments.Moreover,a dedicated dynamic compensation is introduced to deal with the control coefficient coupled with the execution error,based on which a relativethreshold event-triggering mechanism(ETM)is rigorously validated.It turns out that the adaptive event-triggered controller achieves the closed-loop convergence while guaranteeing a uniform lower bound for inter-execution times.Simulation results verify the effectiveness and superiority of the proposed strategy.
基金the National Natural Science Foundation of China(Grant Nos.62303380,62176214,62101590,62003268)the Aeronautical Science Foundation of China(Grant No.201907053001).
文摘This research focuses on detecting faults in flight vehicles with unstable subsystems operating asynchronously.By accounting for asynchronous switching,a switched model is established,and filters for fault detection(FD)in unstable subsystems are developed.The FD challenge is then transformed into an H∞filtering issue.Utilizing the multiple discontinuous Lyapunov function(MDLF)approach and the mode-dependent average dwell time(MDADT)method,sufficient conditions are derived to ensure stability during both fast and slow switching.Furthermore,the existence and solutions for FD filters are provided through linear matrix inequalities(LMIs).The simulation outcomes demonstrated the excellent performance of the developed method in studied cases.
基金Supported by the Natural Science Foundation of Hainan Province(313114)the Sanya Science Project(2013YD89)the Social Science Project(SYSK14-08)~~
文摘Based on winter nursery and shuttle breeding, Hainan National Breeding and Multiplication （HNBM）, with off-season breeding and seed production as the essence, has become a national strategic resource. The way of HNBM rising to the national strategy was analyzed through the aspects of technology features, historical characteristics, irreplaceability, function and value hierarchy, and the key problems. As the major achievement of the practice of scientific research and historical selec- tion, HNBM played an irreplaceable role in the climatic conditions, scientific breed- ing, and seed production in disaster relief, protecting the safety of the seed industry and Iocational advantages. Based on the analysis on the functions, values and ex- isted problems of HNBM, the function and value hierarchical structure of HNBM was established through introducing concepts of value engineering, industrial clusters and regional economy. But to fully achieve the industrial clustering development and functional values of HNBM, it needed to solve the key problems existed in top-level planning, experimental bases, system design, hardware construction and ecological security. Some suggestions were put forward in this paper, including setting up key scientific research protection zones, improving the regulations and policies safeguard mechanism and management system of HNBM, drawing up and carrying out the base development planning of HNBM, and striving for financial support from national policies.
基金The National Natural Science Foundation of China(No.61273119,61104068,61374038)the Natural Science Foundation of Jiangsu Province(No.BK2011253)
文摘The exponential stabilization problem for finite dimensional switched systems is extended to the infinite dimensional distributed parameter systems in the Hilbert space. Based on the semigroup theory, by applying the multiple Lyapunov function method, the exponential stabilization conditions are derived. These conditions are given in the form of linear operator inequalities where the decision variables are operators in the Hilbert space; while the stabilization properties depend on the switching rule. Being applied to the two-dimensional heat switched propagation equations with the Dirichlet boundary conditions, these linear operator inequalities are transformed into standard linear matrix inequalities. Finally, two examples are given to illustrate the effectiveness of the proposed results.
基金This work was supported by the National Natural Science Foundation of China (No.60574013, 60274009), and the Natural Science Fundation ofLiaoning Province (No.20032020).
文摘This paper deals with the problem of switching between an open-loop estimator and a close-loop estimator for compensating transmission error and packet dropout of networked control systems. Switching impulse is considered in order to reduce the error between theory and application, a sufficient condition for exponential stabilization of networked control systems under a given switching rule is presented by multiple Lyapunov-like functions. These results are presented for both continuous-time and discrete-time domains. Controllers are designed by means of linear matrix inequalities. Sim- ulation results show the feasibility and efficiency of the proposed method.
基金This work was supported by the National Natural Science Foundation of China(No. 60474034).
文摘This paper is concerned with controller synthesis for linear switched systems with actuator saturation. Based on common Lyapunov function technique and multiple-Lyapunov function technique, two methods for designing state feedback controller are proposed respectively in terms of linear matrix inequalities for the switched systems with saturation. An approach on enlarging the attractive domain is then investigated, The application of the presented approach is illustrated finally by a numerical example.
基金supported by the National Natural Science Foundation of China(61304058,61233002)IAPI Fundamental Research Funds(2013ZCX03-01)
文摘This paper focuses on the H_∞ model reference tracking control for a switched linear parameter-varying(LPV)model representing an aero-engine. The switched LPV aeroengine model is built based on a family of linearized models.Multiple parameter-dependent Lyapunov functions technique is used to design a tracking control law for the desirable H_∞ tracking performance. A control synthesis condition is formulated in terms of the solvability of a matrix optimization problem.Simulation result on the aero-engine model shows the feasibility and validity of the switching tracking control scheme.
