In the present paper the transformation of symmetric Markov processes by symmetric martingale multiplicative functionals is studied and the corresponding Dirichlet form is formulated.
The authors introduce concepts of even and odd additive functionals and prove that an even martingale continuous additive functional of a symmetric Markov process vanishes identically.A representation for symmetric s...The authors introduce concepts of even and odd additive functionals and prove that an even martingale continuous additive functional of a symmetric Markov process vanishes identically.A representation for symmetric super-martingale multiplicative functionals are also given.展开更多
By using the unsymmetrical scale instead of the symmetrical scale,the multiplicative intuitionistic fuzzy sets(MIFSs) reflect our intuition more objectively.Each element in a MIFS is expressed by an ordered pair which...By using the unsymmetrical scale instead of the symmetrical scale,the multiplicative intuitionistic fuzzy sets(MIFSs) reflect our intuition more objectively.Each element in a MIFS is expressed by an ordered pair which is called a multiplicative intuitionistic fuzzy number(MIFN)and is based on the unbalanced scale(i.e.,Saaty’s 1-9 scale).In order to describe the derivatives and differentials for multiplicative intuitionistic fuzzy information more comprehensively,in this paper,we firstly propose two new basic operational laws for MIFNs,which are the subtraction law and the division law.Secondly,we describe the change values of MIFNs when considering them as variables,classify these change values based on the basic operational laws for MIFNs,and depict the convergences of sequences of MIFNs by the subtraction and division laws.Finally,we focus on the multiplicative intuitionistic fuzzy functions and derive some basic results related to their continuities,derivatives and differentials,and also give their application in selecting the configuration of a computer.展开更多
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 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
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
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
Sodium-sulfur(Na–S)batteries that utilize earth-abundant materials of Na and S have been one of the hottest topics in battery research.The low cost and high energy density make them promising candidates for next-gene...Sodium-sulfur(Na–S)batteries that utilize earth-abundant materials of Na and S have been one of the hottest topics in battery research.The low cost and high energy density make them promising candidates for next-generation storage technologies as required in the grid and renewable energy.In recent years,extensive efforts have been devoted to the diversity and functionalities of Na–S batteries,aiming to extend their potential applications across multiple temporal and spatial dimensions.Here,we summarize the unconventional designs for the functionalities of Na–S batteries such as flexible batteries,solid-state cells,flame resistance,and operation at extreme temperatures.By highlighting these design strategies that help to realize the functionalities,we hope this review offers a pathway to foster the bright future of Na–S batteries in diverse applications.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
A sufficient condition for the existence of nonfragile state-feedback controllers and a switching law for a class of uncertain switching fuzzy time-delay systems are proposed based on the multiple Lyapunov functions t...A sufficient condition for the existence of nonfragile state-feedback controllers and a switching law for a class of uncertain switching fuzzy time-delay systems are proposed based on the multiple Lyapunov functions technique, under the assumption that the controller gain to be designed has variations. The corresponding results are all formulated in terms of linear matrix inequalities (LMIs). Simulation results show the effectiveness of the design method.展开更多
The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material.The holes will lead to mutations and discontinuity to ...The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material.The holes will lead to mutations and discontinuity to the structure.So the hole-edge stress concentration is always a serious phenomenon.And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points.Most partial damage begins from these weak points.According to the complex variable functions theory,the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes.Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction.The boundary integral equations are founded based on exact boundary conditions.Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved.Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed.And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made.It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient;and smaller angle of outer load and fiber can decrease the stress peak value.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 proposes a method for the stability analysis of deterministic switched systems.Two motivational examples are introduced （nonholonomic system and constrained pendulum）.The finite collection of models consi...This paper proposes a method for the stability analysis of deterministic switched systems.Two motivational examples are introduced （nonholonomic system and constrained pendulum）.The finite collection of models consists of nonlinear models,and a switching sequence is arbitrary.It is supposed that there is no jump in the state at switching instants,and there is no Zeno behavior,i.e.,there is a finite number of switches on every bounded interval.For the analysis of deterministic switched systems,the multiple Lyapunov functions are used,and the global exponential stability is proved.The exponentially stable equilibrium of systems is relevant for practice because such systems are robust to perturbations.展开更多
Motivated by the autopilot of an unmanned aerial vehicle（UAV） with a wide flight envelope span experiencing large parametric variations in the presence of uncertainties, a fuzzy adaptive tracking controller（FATC） ...Motivated by the autopilot of an unmanned aerial vehicle（UAV） with a wide flight envelope span experiencing large parametric variations in the presence of uncertainties, a fuzzy adaptive tracking controller（FATC） is proposed. The controller consists of a fuzzy baseline controller and an adaptive increment, and the main highlight is that the fuzzy baseline controller and adaptation laws are both based on the fuzzy multiple Lyapunov function approach, which helps to reduce the conservatism for the large envelope and guarantees satisfactory tracking performances with strong robustness simultaneously within the whole envelope. The constraint condition of the fuzzy baseline controller is provided in the form of linear matrix inequality（LMI）, and it specifies the satisfactory tracking performances in the absence of uncertainties. The adaptive increment ensures the uniformly ultimately bounded（UUB） predication errors to recover satisfactory responses in the presence of uncertainties. Simulation results show that the proposed controller helps to achieve high-accuracy tracking of airspeed and altitude desirable commands with strong robustness to uncertainties throughout the entire flight envelope.展开更多
基金in partby the National Natural Science Founda-tion of China(1 950 1 0 36)
文摘In the present paper the transformation of symmetric Markov processes by symmetric martingale multiplicative functionals is studied and the corresponding Dirichlet form is formulated.
基金Project supported by the National Natural Science Foundation of China.
文摘The authors introduce concepts of even and odd additive functionals and prove that an even martingale continuous additive functional of a symmetric Markov process vanishes identically.A representation for symmetric super-martingale multiplicative functionals are also given.
基金supported in part by the National Natural Science Foundation of China(71571123,71771155)
文摘By using the unsymmetrical scale instead of the symmetrical scale,the multiplicative intuitionistic fuzzy sets(MIFSs) reflect our intuition more objectively.Each element in a MIFS is expressed by an ordered pair which is called a multiplicative intuitionistic fuzzy number(MIFN)and is based on the unbalanced scale(i.e.,Saaty’s 1-9 scale).In order to describe the derivatives and differentials for multiplicative intuitionistic fuzzy information more comprehensively,in this paper,we firstly propose two new basic operational laws for MIFNs,which are the subtraction law and the division law.Secondly,we describe the change values of MIFNs when considering them as variables,classify these change values based on the basic operational laws for MIFNs,and depict the convergences of sequences of MIFNs by the subtraction and division laws.Finally,we focus on the multiplicative intuitionistic fuzzy functions and derive some basic results related to their continuities,derivatives and differentials,and also give their application in selecting the configuration of a computer.
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..
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.
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.
基金supported by the National Natural Science Foundation of China(52172219 and 51872192)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(19KJA170001)+1 种基金the Fundamental Research Program of Shanxi Province(202103021223019)Science and Technology Major Project of Shanxi(No.202101030201022)
文摘Sodium-sulfur(Na–S)batteries that utilize earth-abundant materials of Na and S have been one of the hottest topics in battery research.The low cost and high energy density make them promising candidates for next-generation storage technologies as required in the grid and renewable energy.In recent years,extensive efforts have been devoted to the diversity and functionalities of Na–S batteries,aiming to extend their potential applications across multiple temporal and spatial dimensions.Here,we summarize the unconventional designs for the functionalities of Na–S batteries such as flexible batteries,solid-state cells,flame resistance,and operation at extreme temperatures.By highlighting these design strategies that help to realize the functionalities,we hope this review offers a pathway to foster the bright future of Na–S batteries in diverse applications.
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.
基金supported by the National Natural Science Foundation of China (No.60874024, 60574013, 90816028)the Specialized Research Fund for the Doctoral Program of Higher Education of China (No.200801450019)
文摘A sufficient condition for the existence of nonfragile state-feedback controllers and a switching law for a class of uncertain switching fuzzy time-delay systems are proposed based on the multiple Lyapunov functions technique, under the assumption that the controller gain to be designed has variations. The corresponding results are all formulated in terms of linear matrix inequalities (LMIs). Simulation results show the effectiveness of the design method.
基金supported by National Natural Science Foundation of China(No.50675209)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education of China(No.200724).
文摘The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material.The holes will lead to mutations and discontinuity to the structure.So the hole-edge stress concentration is always a serious phenomenon.And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points.Most partial damage begins from these weak points.According to the complex variable functions theory,the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes.Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction.The boundary integral equations are founded based on exact boundary conditions.Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved.Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed.And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made.It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient;and smaller angle of outer load and fiber can decrease the stress peak value.
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 Ministry of Science and Technological Development of the Republic of Serbia (No. TR-3326)
文摘This paper proposes a method for the stability analysis of deterministic switched systems.Two motivational examples are introduced （nonholonomic system and constrained pendulum）.The finite collection of models consists of nonlinear models,and a switching sequence is arbitrary.It is supposed that there is no jump in the state at switching instants,and there is no Zeno behavior,i.e.,there is a finite number of switches on every bounded interval.For the analysis of deterministic switched systems,the multiple Lyapunov functions are used,and the global exponential stability is proved.The exponentially stable equilibrium of systems is relevant for practice because such systems are robust to perturbations.
文摘Motivated by the autopilot of an unmanned aerial vehicle（UAV） with a wide flight envelope span experiencing large parametric variations in the presence of uncertainties, a fuzzy adaptive tracking controller（FATC） is proposed. The controller consists of a fuzzy baseline controller and an adaptive increment, and the main highlight is that the fuzzy baseline controller and adaptation laws are both based on the fuzzy multiple Lyapunov function approach, which helps to reduce the conservatism for the large envelope and guarantees satisfactory tracking performances with strong robustness simultaneously within the whole envelope. The constraint condition of the fuzzy baseline controller is provided in the form of linear matrix inequality（LMI）, and it specifies the satisfactory tracking performances in the absence of uncertainties. The adaptive increment ensures the uniformly ultimately bounded（UUB） predication errors to recover satisfactory responses in the presence of uncertainties. Simulation results show that the proposed controller helps to achieve high-accuracy tracking of airspeed and altitude desirable commands with strong robustness to uncertainties throughout the entire flight envelope.
