Since 2005,dozens of geographical observational stations have been established in the Heihe River Basin(HRB),and by now a large amount of meteorological,hydrological,and ecological observations as well as data pertain...Since 2005,dozens of geographical observational stations have been established in the Heihe River Basin(HRB),and by now a large amount of meteorological,hydrological,and ecological observations as well as data pertaining to water resources,soil and vegetation have been collected.To adequately analyze these available data and data to be further collected in future,we present a perspective from complexity theory.The concrete materials covered include a presentation of adaptive multiscale filter,which can readily determine arbitrary trends,maximally reduce noise,and reliably perform fractal and multifractal analysis,and a presentation of scale-dependent Lyapunov exponent(SDLE),which can reliably distinguish deterministic chaos from random processes,determine the error doubling time for prediction,and obtain the defining parameters of the process examined.The adaptive filter is illustrated by applying it to obtain the global warming trend and the Atlantic multidecadal oscillation from sea surface temperature data,and by applying it to some variables collected at the HRB to determine diurnal cycle and fractal properties.The SDLE is illustrated to determine intermittent chaos from river flow data.展开更多
In this paper, we consider the distributed adaptive fault-tolerant output regulation problem for heterogeneous multiagent systems with matched system uncertainties and mismatched coupling uncertainties among subsystem...In this paper, we consider the distributed adaptive fault-tolerant output regulation problem for heterogeneous multiagent systems with matched system uncertainties and mismatched coupling uncertainties among subsystems under the influence of actuator faults. First, distributed finite-time observers are proposed for all subsystems to observe the state of the exosystem. Then, a novel fault-tolerant controller is designed to compensate for the influence of matched system uncertainties and actuator faults. By using the linear matrix inequality technique, a sufficient condition is provided to guarantee the solvability of the considered problem in the presence of mismatched coupling uncertainties. Moreover, it is shown that the system in closed-loop with the developed controller can achieve output regulation by using the Lyapunov stability theory and cyclic-small-gain theory.Finally, a numerical example is given to illustrate the effectiveness of the obtained result.展开更多
In this paper, the robust adaptive fuzzy tracking control problem is discussed for a class of perturbed strict-feedback nonlinear systems. The fuzzy logic systems in Mamdani type are used to approximate unknown nonlin...In this paper, the robust adaptive fuzzy tracking control problem is discussed for a class of perturbed strict-feedback nonlinear systems. The fuzzy logic systems in Mamdani type are used to approximate unknown nonlinear functions. A design scheme of the robust adaptive fuzzy controller is proposed by use of the backstepping technique. The proposed controller guarantees semi-global uniform ultimate boundedness of all the signals in the derived closed-loop system and achieves the good tracking performance. The possible controller singularity problem which may occur in some existing adaptive control schemes with feedback linearization techniques can be avoided. In addition, the number of the on-line adaptive parameters is not more than the order of the designed system. Finally, two simulation examples are used to demonstrate the effectiveness of the proposed control scheme.展开更多
Dear Editor, In recent decades, owing to the significance of sampled-data control way on reducing the burden of communication transmission and improving the control capability of networked control systems, the researc...Dear Editor, In recent decades, owing to the significance of sampled-data control way on reducing the burden of communication transmission and improving the control capability of networked control systems, the research of sampled-data systems has become increasingly important(see [1]–[5]).展开更多
A Yb_（0.11）Gd_（0.89）Ca_4O（BO_3）_3 crystal with new composition was grown by the Czochralski method. The crystal structure was measured and analyzed. The unit-cell parameters of the Yb_（0.11）Gd_（0.89）COB were...A Yb_（0.11）Gd_（0.89）Ca_4O（BO_3）_3 crystal with new composition was grown by the Czochralski method. The crystal structure was measured and analyzed. The unit-cell parameters of the Yb_（0.11）Gd_（0.89）COB were calculated to be a=0.8089（7） nm, b=1.5987（6） nm, c=0.3545（8） nm, β=101.22o. The absorption and fluorescence spectra were measured. The maximum absorption cross-section of Yb_（0.11）Gd_（0.89） COB crystal was 0.79×10^（–20）cm^2, which occurred at 976 nm with Y polarization. The emission cross-section at 1027 nm was calculated to be 0.33×10^（–20） cm^2. The radiative lifetime trad was calculated to be 2.74 ms. The Stark energy-level diagram of Yb^（3＋）in the Yb_（0.11）Gd_（0.89）COB crystal field at room temperature was determined. The ground-state energy level ~2F_（7/2） splitting was calculated to be as large as 1004 cm^（–1） and the zero-line energy was 10246 cm^（–1）. A maximum output power of 9.35 W was achieved in continuous-wave（CW） mode, with the slope efficiency being 42.1%. Chemical etching experiment revealed that the dominating imperfections in the studied Yb_（0.11）Gd_（0.89） COB crystal were dislocations and sub-grain boundaries. The existence of crystal defects could cause light scattering, and degrade laser output efficiency. The influence of crystal defects on laser properties was discussed.展开更多
In this paper, the relations of the network topology and the moving consensus of multi-agent systems are studied. A consensus-prestissimo scale-free network model with the static preferential-consensus attachment is p...In this paper, the relations of the network topology and the moving consensus of multi-agent systems are studied. A consensus-prestissimo scale-free network model with the static preferential-consensus attachment is presented on the rewired link of the regular network. The effects of the static preferential-consensus BA network on the algebraic connectivity of the topology graph are compared with the regular network. The robustness gain to delay is analyzed for variable network topology with the same scale. The time to reach the consensus is studied for the dynamic network with and without communication delays. By applying the computer simulations, it is validated that the speed of the convergence of multi-agent systems can be greatly improved in the preferential-consensus BA network model with different configuration.展开更多
This paper investigates the polynomial synchronization(PS)problem of complex-valued inertial neural networks with multi-proportional delays.It is analyzed based on the non-separation method.Firstly,an exponential tran...This paper investigates the polynomial synchronization(PS)problem of complex-valued inertial neural networks with multi-proportional delays.It is analyzed based on the non-separation method.Firstly,an exponential transformation is applied and an appropriate controller is designed.Then,a new sufficient criterion for PS of the considered system is derived by the Lyapunov function approach and some inequalities techniques.In the end,a numerical example is given to illustrate the effectiveness of the obtained result.展开更多
High quality, concentrated sugar syrup crystal is produced in a critical step in cane sugar production： the clarification process. It is characterized by two variables： the color of the produced sugar and its clarit...High quality, concentrated sugar syrup crystal is produced in a critical step in cane sugar production： the clarification process. It is characterized by two variables： the color of the produced sugar and its clarity degree. We show that the temporal variations of these variables follow power-law distributions and can be well modeled by multiplicative cascade multifractal processes. These interesting properties suggest that the degradation in color and clarity degree has a systemwide cause. In particular, the cascade multifractal model suggests that the degradation in color and clarity degree can be equivalently accounted for by the initial ＂impurities＂ in the sugarcane. Hence, more effective cleaning of the sugarcane before the clarification stage may lead to substantial improvement in the effect of clarification.展开更多
This paper proposes an indirect adaptive neural control scheme for a class of nonlinear systems with time delays. Based on the backstepping technique and Lyapunov – Krasovskii functional method are combined to constr...This paper proposes an indirect adaptive neural control scheme for a class of nonlinear systems with time delays. Based on the backstepping technique and Lyapunov – Krasovskii functional method are combined to construct the indirect adaptive neural controller. The proposed indirect adaptive neural controller guarantees that the state variables converge to a small neighborhood of the origin and all the signals of the closedloop system are bounded. Finally, an example is used to show the effectiveness of the proposed control strategy.展开更多
The multi-agent controllability is intrinsically affected by the network topology and the selection of leaders.A focus of exploring this problem is to uncover the relationship between the eigenspace of Laplacian matri...The multi-agent controllability is intrinsically affected by the network topology and the selection of leaders.A focus of exploring this problem is to uncover the relationship between the eigenspace of Laplacian matrix and network topology.For strongly connected directed circle graphs,we elaborate how the zero entries in the left eigenvectors of Laplacian matrix L arise.The topologies arising from left eigenvectors with zero entries are filtered to construct essentially controllable directed circle graphs regardless of the choice of leaders.We propose two methods for constructing a substantial quantity of essentially controllable graphs,with a focus on utilizing essentially controllable circle graphs as the foundation.For a special directed graph-OT tree,the controllability is shown to be related with its substructure-paths.This promotes the establishment of a sufficient and necessary condition for controllability.Finally,a method is presented to check the controllable subspace by identifying the left eigenvectors and generalized left eigenvectors.展开更多
Human-in-the-loop(HiTL)control is promising for the cooperative control problem of multi-agent systems(MASs)under the complicated environment.By considering the effect of human intelligence and decision making,the sys...Human-in-the-loop(HiTL)control is promising for the cooperative control problem of multi-agent systems(MASs)under the complicated environment.By considering the effect of human intelligence and decision making,the system robustness and security are notably enhanced.Hence,a distributed fixed-time tracking control problem is investigated in this paper for heterogeneous MASs based on the HiTL idea.First,a lemma of practically fixed-time stable is given where an explicit relationship of settling time and convergence domain is clearly shown.Then,under the framework of the adaptive backstepping approach,a series of modified intermediate control signals is designed to avoid the singularity problem by taking advantage of power transformation,fuzzy logic systems,and inequality schemes.Finally,the numerical example and comparison results are utilized to testify the effectiveness of the proposed method.展开更多
This paper investigates the controllability of general linear discrete-time multi-agent systems with directed and weighted signed networks by using graphic and algebraic methods.The nondelay and delay cases are consid...This paper investigates the controllability of general linear discrete-time multi-agent systems with directed and weighted signed networks by using graphic and algebraic methods.The nondelay and delay cases are considered respectively.For the case of no time delay,the upper bound condition of the controllable subspace is given by using the equitable partition method,and the influence of coefficient matrix selection of individual dynamics is illustrated.For the case of single delay and multiple delays,the equitable partition method is extended to deal with time-delay systems,and some conclusions are obtained.In particular,some simplified algebraic criteria for controllability of systems with time delay are obtained by using augmented system method and traditional algebraic controllability criteria.展开更多
In this paper,the irrational-behavior-proof conditions in a class of stochastic dynamic games over event trees are presented.Four kinds of irrational-behavior-proof conditions are proposed by the imputation distributi...In this paper,the irrational-behavior-proof conditions in a class of stochastic dynamic games over event trees are presented.Four kinds of irrational-behavior-proof conditions are proposed by the imputation distribution procedure,and their relationships are discussed.More specific properties for the general transformation of characteristic functions are developed,based on which,the irrational-behavior-proof conditions are proved to be true in a transformed cooperative game.展开更多
In this paper,we investigate the observer-based event-triggered consensus problem for linear multi-agent systems(MASs)under a directed graph and denial-of-service(DoS)attacks.A type of DoS attacks launched by maliciou...In this paper,we investigate the observer-based event-triggered consensus problem for linear multi-agent systems(MASs)under a directed graph and denial-of-service(DoS)attacks.A type of DoS attacks launched by malicious attackers at irregular intervals is considered,which can cause communication channel disruption.A novel event-triggered secure control scheme based on a closed-loop observer is proposed to determine the scheduling of the controller update,and a separation method with less conservativeness is employed to design the controller and observer gains.Then,the frequency and duration of DoS attacks that can be tolerated are analysed for the observer-based secure consensus problem.In addition,a strictly positive minimal event-triggered time interval for each agent is designed with the help of the proposed eventtriggered condition to eliminate the Zeno behaviour.Finally,a numerical simulation is given to verify the theoretical analysis.展开更多
For automated container terminals,the effective integrated scheduling of different kinds of equipment such as quay cranes(QCs),automated guided vehicles(AGVs),and yard cranes(YCs)is of great significance in reducing e...For automated container terminals,the effective integrated scheduling of different kinds of equipment such as quay cranes(QCs),automated guided vehicles(AGVs),and yard cranes(YCs)is of great significance in reducing energy consumption and achieving sustainable development.Aiming at the joint scheduling of AGVs and YCs with consideration of conflict-free path planning for AGVs as well as capacity constraints on AGV-mate which is also called buffer bracket in blocks,a mixed integer programming model is established to minimize the energy consumption of AGVs and YCs for the given loading/unloading task.A solution method based on a novel bi-level genetic algorithm(BGA),in which the outer and the inner layer search the optimal dispatching strategy for QCs and YCs,respectively,is designed.The validity of the model and the algorithm is verified by simulation experiments,which take the Port of Qingdao as an example and the performance under different conflicting resolution strategies is compared.The results show that,for the given task,the proposed solution to conflict-free path and the schedule provided by the algorithm can complete the task with minimum energy consumption without loss of AGVs utilization,and the number of AGV-mates should be adjusted according to the task rather than keeping unchanged.Comparison results indicate that our proposed approach could efficiently find solutions within 6%optimality gaps.Energy consumption is dropped by an average of 15%.展开更多
The blood flow model admits the steady state,in which the flux gradient is non-zero and is exactly balanced by the source term.In this paper,we present a high order well-balanced finite difference weighted essentially...The blood flow model admits the steady state,in which the flux gradient is non-zero and is exactly balanced by the source term.In this paper,we present a high order well-balanced finite difference weighted essentially non-oscillatory(WENO)scheme,which exactly preserves the steady state.In order to maintain the wellbalanced property,we propose to reformulate the equation and apply a novel source term approximation.Extensive numerical experiments are carried out to verify the performances of the current scheme such as the maintenance of well-balanced property,the ability to capture the perturbations of such steady state and the genuine high order accuracy for smooth solutions.展开更多
This paper addresses the asymptotic control problem of uncertain multi-input and multi-output(MIMO)nonlinear systems.The considered MIMO systems contain unknown virtual control coefficients(UVCCs)and state constraints...This paper addresses the asymptotic control problem of uncertain multi-input and multi-output(MIMO)nonlinear systems.The considered MIMO systems contain unknown virtual control coefficients(UVCCs)and state constraints.Acreative Lyapunov function by associating with the lower bounds of UVCCs is presented to counteract the adverse effect deriving from UVCCs.The state constraints are ensured by utilising the barrier Lyapunov function.Moreover,the asymptotic tracking controller is recursively constructed by combining the backstepping technique with fuzzy logic systems.The remarkable character of the designed controller is that the asymptotic tracking performance can be achieved by introducing some smooth functions into adaptive backstepping procedure.In contrast to the existing results,the conditions on the UVCCs are relaxed.Finally,the new control design is illustrated by a practical example.展开更多
基金National Natural Science Foundation of China,No.71661002,No.41671532National Key R&D Program of China,No.2017YFB0504102The Fundamental Research Funds for the Central Universities
文摘Since 2005,dozens of geographical observational stations have been established in the Heihe River Basin(HRB),and by now a large amount of meteorological,hydrological,and ecological observations as well as data pertaining to water resources,soil and vegetation have been collected.To adequately analyze these available data and data to be further collected in future,we present a perspective from complexity theory.The concrete materials covered include a presentation of adaptive multiscale filter,which can readily determine arbitrary trends,maximally reduce noise,and reliably perform fractal and multifractal analysis,and a presentation of scale-dependent Lyapunov exponent(SDLE),which can reliably distinguish deterministic chaos from random processes,determine the error doubling time for prediction,and obtain the defining parameters of the process examined.The adaptive filter is illustrated by applying it to obtain the global warming trend and the Atlantic multidecadal oscillation from sea surface temperature data,and by applying it to some variables collected at the HRB to determine diurnal cycle and fractal properties.The SDLE is illustrated to determine intermittent chaos from river flow data.
基金supported in part by the National Natural Science Foundation of China(61473195,61603081,61773131,61773056,61873306,U1966202,61803305,61873338)the China Postdoctoral Science Foundation(2015M580513)Research Fund for the Taishan Scholar Project of Shandong Province of China(TSQN201812052)。
文摘In this paper, we consider the distributed adaptive fault-tolerant output regulation problem for heterogeneous multiagent systems with matched system uncertainties and mismatched coupling uncertainties among subsystems under the influence of actuator faults. First, distributed finite-time observers are proposed for all subsystems to observe the state of the exosystem. Then, a novel fault-tolerant controller is designed to compensate for the influence of matched system uncertainties and actuator faults. By using the linear matrix inequality technique, a sufficient condition is provided to guarantee the solvability of the considered problem in the presence of mismatched coupling uncertainties. Moreover, it is shown that the system in closed-loop with the developed controller can achieve output regulation by using the Lyapunov stability theory and cyclic-small-gain theory.Finally, a numerical example is given to illustrate the effectiveness of the obtained result.
基金This work was supported by the National Natural Science Foundation of China (No.60674055)the Taishan Scholar programme and the NaturalScience Foundation of Shandong Province (No.Y2006G04)
文摘In this paper, the robust adaptive fuzzy tracking control problem is discussed for a class of perturbed strict-feedback nonlinear systems. The fuzzy logic systems in Mamdani type are used to approximate unknown nonlinear functions. A design scheme of the robust adaptive fuzzy controller is proposed by use of the backstepping technique. The proposed controller guarantees semi-global uniform ultimate boundedness of all the signals in the derived closed-loop system and achieves the good tracking performance. The possible controller singularity problem which may occur in some existing adaptive control schemes with feedback linearization techniques can be avoided. In addition, the number of the on-line adaptive parameters is not more than the order of the designed system. Finally, two simulation examples are used to demonstrate the effectiveness of the proposed control scheme.
基金supported in part by the National Natural Science Foundation of China (61873137, 61973179)the Shandong Taishan Scholar Project (ts20190930)。
文摘Dear Editor, In recent decades, owing to the significance of sampled-data control way on reducing the burden of communication transmission and improving the control capability of networked control systems, the research of sampled-data systems has become increasingly important(see [1]–[5]).
基金Project supported by National Natural Science Foundation of China(11204148,11374170)Taishan Scholar Program of Shandong Province+2 种基金Open Project of State Key Laboratory of Rare Earth Resource Utilization(RERU2016015)the Applied Basic Research Programs for Youths of Qingdao(15-9-1-52-JCH)Qingdao Postdoctoral Application Research Project(2015127)
文摘A Yb_（0.11）Gd_（0.89）Ca_4O（BO_3）_3 crystal with new composition was grown by the Czochralski method. The crystal structure was measured and analyzed. The unit-cell parameters of the Yb_（0.11）Gd_（0.89）COB were calculated to be a=0.8089（7） nm, b=1.5987（6） nm, c=0.3545（8） nm, β=101.22o. The absorption and fluorescence spectra were measured. The maximum absorption cross-section of Yb_（0.11）Gd_（0.89） COB crystal was 0.79×10^（–20）cm^2, which occurred at 976 nm with Y polarization. The emission cross-section at 1027 nm was calculated to be 0.33×10^（–20） cm^2. The radiative lifetime trad was calculated to be 2.74 ms. The Stark energy-level diagram of Yb^（3＋）in the Yb_（0.11）Gd_（0.89）COB crystal field at room temperature was determined. The ground-state energy level ~2F_（7/2） splitting was calculated to be as large as 1004 cm^（–1） and the zero-line energy was 10246 cm^（–1）. A maximum output power of 9.35 W was achieved in continuous-wave（CW） mode, with the slope efficiency being 42.1%. Chemical etching experiment revealed that the dominating imperfections in the studied Yb_（0.11）Gd_（0.89） COB crystal were dislocations and sub-grain boundaries. The existence of crystal defects could cause light scattering, and degrade laser output efficiency. The influence of crystal defects on laser properties was discussed.
基金Supported in part by Chinese National Natural Science Foundation under Grant Nos. 60774016 60875039+2 种基金 60904022 60805039the Science Foundation of Education Office of Shandong Province of China under Grant No. J08LJ01
文摘In this paper, the relations of the network topology and the moving consensus of multi-agent systems are studied. A consensus-prestissimo scale-free network model with the static preferential-consensus attachment is presented on the rewired link of the regular network. The effects of the static preferential-consensus BA network on the algebraic connectivity of the topology graph are compared with the regular network. The robustness gain to delay is analyzed for variable network topology with the same scale. The time to reach the consensus is studied for the dynamic network with and without communication delays. By applying the computer simulations, it is validated that the speed of the convergence of multi-agent systems can be greatly improved in the preferential-consensus BA network model with different configuration.
基金the National Natural Science Foundation of China (61503222, 62173214)the Natural Science Foundation of Shandong Province of China (ZR2021MF100)+2 种基金the Research Fund for the Taishan Scholar Project of Shandong Province of Chinain part by the Science and Technology Support Plan for Youth Innovation of Colleges and Universities of Shandong Province of China (2019KJI005)in part by the SDUST Research Fund
文摘This paper investigates the polynomial synchronization(PS)problem of complex-valued inertial neural networks with multi-proportional delays.It is analyzed based on the non-separation method.Firstly,an exponential transformation is applied and an appropriate controller is designed.Then,a new sufficient criterion for PS of the considered system is derived by the Lyapunov function approach and some inequalities techniques.In the end,a numerical example is given to illustrate the effectiveness of the obtained result.
文摘High quality, concentrated sugar syrup crystal is produced in a critical step in cane sugar production： the clarification process. It is characterized by two variables： the color of the produced sugar and its clarity degree. We show that the temporal variations of these variables follow power-law distributions and can be well modeled by multiplicative cascade multifractal processes. These interesting properties suggest that the degradation in color and clarity degree has a systemwide cause. In particular, the cascade multifractal model suggests that the degradation in color and clarity degree can be equivalently accounted for by the initial ＂impurities＂ in the sugarcane. Hence, more effective cleaning of the sugarcane before the clarification stage may lead to substantial improvement in the effect of clarification.
文摘This paper proposes an indirect adaptive neural control scheme for a class of nonlinear systems with time delays. Based on the backstepping technique and Lyapunov – Krasovskii functional method are combined to construct the indirect adaptive neural controller. The proposed indirect adaptive neural controller guarantees that the state variables converge to a small neighborhood of the origin and all the signals of the closedloop system are bounded. Finally, an example is used to show the effectiveness of the proposed control strategy.
基金supported by the National Natural Science Foundation of China(62373205,62033007)Taishan Scholars Climbing Program of Shandong Province of China,and Taishan Scholars Project of Shandong Province of China(tstp20230624,ts20190930).
文摘The multi-agent controllability is intrinsically affected by the network topology and the selection of leaders.A focus of exploring this problem is to uncover the relationship between the eigenspace of Laplacian matrix and network topology.For strongly connected directed circle graphs,we elaborate how the zero entries in the left eigenvectors of Laplacian matrix L arise.The topologies arising from left eigenvectors with zero entries are filtered to construct essentially controllable directed circle graphs regardless of the choice of leaders.We propose two methods for constructing a substantial quantity of essentially controllable graphs,with a focus on utilizing essentially controllable circle graphs as the foundation.For a special directed graph-OT tree,the controllability is shown to be related with its substructure-paths.This promotes the establishment of a sufficient and necessary condition for controllability.Finally,a method is presented to check the controllable subspace by identifying the left eigenvectors and generalized left eigenvectors.
基金the National Natural Science Foundation of China(Grant Nos.62373208,62003097,62033003,61873139,62103214 and 62203245)the Talent Introduction and Cultivation Plan for Youth Innovation of Universities in Shandong Province。
文摘Human-in-the-loop(HiTL)control is promising for the cooperative control problem of multi-agent systems(MASs)under the complicated environment.By considering the effect of human intelligence and decision making,the system robustness and security are notably enhanced.Hence,a distributed fixed-time tracking control problem is investigated in this paper for heterogeneous MASs based on the HiTL idea.First,a lemma of practically fixed-time stable is given where an explicit relationship of settling time and convergence domain is clearly shown.Then,under the framework of the adaptive backstepping approach,a series of modified intermediate control signals is designed to avoid the singularity problem by taking advantage of power transformation,fuzzy logic systems,and inequality schemes.Finally,the numerical example and comparison results are utilized to testify the effectiveness of the proposed method.
基金the National Natural Science Foundation of China under Grant Nos.61873136 and 62033007Taishan Scholars Climbing Program of Shandong Province of China and Taishan Scholars Project of Shandong Province of China under Grant No.ts20190930。
文摘This paper investigates the controllability of general linear discrete-time multi-agent systems with directed and weighted signed networks by using graphic and algebraic methods.The nondelay and delay cases are considered respectively.For the case of no time delay,the upper bound condition of the controllable subspace is given by using the equitable partition method,and the influence of coefficient matrix selection of individual dynamics is illustrated.For the case of single delay and multiple delays,the equitable partition method is extended to deal with time-delay systems,and some conclusions are obtained.In particular,some simplified algebraic criteria for controllability of systems with time delay are obtained by using augmented system method and traditional algebraic controllability criteria.
基金supported by National Natural Science Foundation of China(No.72171126)China Postdoctoral Science Foundation(No.2016M600525)Qingdao Postdoctoral Application Research Project(No.2016029).
文摘In this paper,the irrational-behavior-proof conditions in a class of stochastic dynamic games over event trees are presented.Four kinds of irrational-behavior-proof conditions are proposed by the imputation distribution procedure,and their relationships are discussed.More specific properties for the general transformation of characteristic functions are developed,based on which,the irrational-behavior-proof conditions are proved to be true in a transformed cooperative game.
基金the National Natural Science Foundation of China[61873338]Natural Science Foundation of Shandong Province[ZR2020KF034]Taishan Scholars[tsqn201812052].
文摘In this paper,we investigate the observer-based event-triggered consensus problem for linear multi-agent systems(MASs)under a directed graph and denial-of-service(DoS)attacks.A type of DoS attacks launched by malicious attackers at irregular intervals is considered,which can cause communication channel disruption.A novel event-triggered secure control scheme based on a closed-loop observer is proposed to determine the scheduling of the controller update,and a separation method with less conservativeness is employed to design the controller and observer gains.Then,the frequency and duration of DoS attacks that can be tolerated are analysed for the observer-based secure consensus problem.In addition,a strictly positive minimal event-triggered time interval for each agent is designed with the help of the proposed eventtriggered condition to eliminate the Zeno behaviour.Finally,a numerical simulation is given to verify the theoretical analysis.
基金This study is supported by the Natural Science Foundation of China under Grant Nos.61673228 and 61072260the Science Technology Program of Qingdao(21-1-2-16-zhz).
文摘For automated container terminals,the effective integrated scheduling of different kinds of equipment such as quay cranes(QCs),automated guided vehicles(AGVs),and yard cranes(YCs)is of great significance in reducing energy consumption and achieving sustainable development.Aiming at the joint scheduling of AGVs and YCs with consideration of conflict-free path planning for AGVs as well as capacity constraints on AGV-mate which is also called buffer bracket in blocks,a mixed integer programming model is established to minimize the energy consumption of AGVs and YCs for the given loading/unloading task.A solution method based on a novel bi-level genetic algorithm(BGA),in which the outer and the inner layer search the optimal dispatching strategy for QCs and YCs,respectively,is designed.The validity of the model and the algorithm is verified by simulation experiments,which take the Port of Qingdao as an example and the performance under different conflicting resolution strategies is compared.The results show that,for the given task,the proposed solution to conflict-free path and the schedule provided by the algorithm can complete the task with minimum energy consumption without loss of AGVs utilization,and the number of AGV-mates should be adjusted according to the task rather than keeping unchanged.Comparison results indicate that our proposed approach could efficiently find solutions within 6%optimality gaps.Energy consumption is dropped by an average of 15%.
基金The authors would like to thank the support of the Natural Science Foundation of China through Grants Nos.11201254 and 41476101the Natural Science Foundation of Shandong Province of China through Grants Nos.ZR2014DM017 and ZR2015PF002the Project for Scientific Plan of Higher Education in Shandong Province of China through Grant No.J12LI08.
文摘The blood flow model admits the steady state,in which the flux gradient is non-zero and is exactly balanced by the source term.In this paper,we present a high order well-balanced finite difference weighted essentially non-oscillatory(WENO)scheme,which exactly preserves the steady state.In order to maintain the wellbalanced property,we propose to reformulate the equation and apply a novel source term approximation.Extensive numerical experiments are carried out to verify the performances of the current scheme such as the maintenance of well-balanced property,the ability to capture the perturbations of such steady state and the genuine high order accuracy for smooth solutions.
基金supported in part by the National Natural Science Foundation of China under grant numbers 52171299 and 61803116,62173103in part by the Fundamental Research Funds for the Central Universities of China under grant number 3072022JC0402.
文摘This paper addresses the asymptotic control problem of uncertain multi-input and multi-output(MIMO)nonlinear systems.The considered MIMO systems contain unknown virtual control coefficients(UVCCs)and state constraints.Acreative Lyapunov function by associating with the lower bounds of UVCCs is presented to counteract the adverse effect deriving from UVCCs.The state constraints are ensured by utilising the barrier Lyapunov function.Moreover,the asymptotic tracking controller is recursively constructed by combining the backstepping technique with fuzzy logic systems.The remarkable character of the designed controller is that the asymptotic tracking performance can be achieved by introducing some smooth functions into adaptive backstepping procedure.In contrast to the existing results,the conditions on the UVCCs are relaxed.Finally,the new control design is illustrated by a practical example.
