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
Many energy efficiency asynchronous duty-cycle MAC(media access control) protocols have been proposed in recent years.However,in these protocols,wireless sensor nodes almost choose their wakeup time randomly during th...Many energy efficiency asynchronous duty-cycle MAC(media access control) protocols have been proposed in recent years.However,in these protocols,wireless sensor nodes almost choose their wakeup time randomly during the operational cycle,which results in the packet delivery latency increased significantly on the multiple hops path.To reduce the packet delivery latency on multi-hop path and energy waste of the sender's idle listening,a new low latency routing-enhanced asynchronous duty-cycle MAC protocol was presented,called REA-MAC.In REA-MAC,each sensor node decided when it waked up to send the beacon based on cross-layer routing information.Furthermore,the sender adaptively waked up based on the relationship between the transmission request time and the wakeup time of its next hop node.The simulation results show that REA-MAC reduces delivery latency by 60% compared to RI-MAC and reduces 8.77% power consumption on average.Under heavy traffic,REA-MAC's throughput is 1.48 times of RI-MAC's.展开更多
This paper presents partially asynchronous parallel simulation of continuous-system (PAPSoCS) and some approaches to the issues of its implementation on a multicomputer system. To guarantee the simulation results cor...This paper presents partially asynchronous parallel simulation of continuous-system (PAPSoCS) and some approaches to the issues of its implementation on a multicomputer system. To guarantee the simulation results correct and speedup the simulation, the scheme for efficient PAPSoCS is proposed and the virtual topology star is constructed to match the path of message passing for solving algorithm-architecture adequation problem. Under the circumstances that messages frequently passed inter-processor are much shorter, typically within several 4 bytes, asynchronous communication mode is employed to reduce the communication ratio. Experiment results show that asynchronous parallel simulation has much higher efficiency than its synchronous counterpart.展开更多
We study distributed optimization problems over a directed network,where nodes aim to minimize the sum of local objective functions via directed communications with neighbors.Many algorithms are designed to solve it f...We study distributed optimization problems over a directed network,where nodes aim to minimize the sum of local objective functions via directed communications with neighbors.Many algorithms are designed to solve it for synchronized or randomly activated implementation,which may create deadlocks in practice.In sharp contrast,we propose a fully asynchronous push-pull gradient(APPG) algorithm,where each node updates without waiting for any other node by using possibly delayed information from neighbors.Then,we construct two novel augmented networks to analyze asynchrony and delays,and quantify its convergence rate from the worst-case point of view.Particularly,all nodes of APPG converge to the same optimal solution at a linear rate of O(λ^(k)) if local functions have Lipschitz-continuous gradients and their sum satisfies the Polyak-?ojasiewicz condition(convexity is not required),where λ ∈(0,1) is explicitly given and the virtual counter k increases by one when any node updates.Finally,the advantage of APPG over the synchronous counterpart and its linear speedup efficiency are numerically validated via a logistic regression problem.展开更多
鉴于农民因信息不对称导致农产品购销渠道不畅,设计开发了一种基于Ajax(Asynchronous JavaScript and XML)的多层体系结构的简单、高效的农产品信息服务平台系统。系统采用异步通信方式实现无刷新下动态页面局部数据更新;提供基于实例...鉴于农民因信息不对称导致农产品购销渠道不畅,设计开发了一种基于Ajax(Asynchronous JavaScript and XML)的多层体系结构的简单、高效的农产品信息服务平台系统。系统采用异步通信方式实现无刷新下动态页面局部数据更新;提供基于实例的信息发布方式;通过自动查询和嵌入手机短信实现信息的配对,从而使系统具有易用性、高效性、便捷性,利于平台的使用推广。展开更多
A kind of networked control system with network-induced delay and packet dropout, modeled on asynchronous dynamical systems was tested, and the integrity design of the networked control system with sensors failures an...A kind of networked control system with network-induced delay and packet dropout, modeled on asynchronous dynamical systems was tested, and the integrity design of the networked control system with sensors failures and actuators failures was analyzed using hybrid systems technique based on the robust fault-tolerant control theory. The parametric expression of controller is given based on the feasible solution of linear matrix inequality. The simulation results are provided on the basis of detailed theoretical analysis, which further demonstrate the validity of the proposed schema.展开更多
Due to the different data rates of the sensors and communication delays in the radar netting, the research of the asynchronous multisensor data fusion problem is more practical than that of the synchronous one. Throug...Due to the different data rates of the sensors and communication delays in the radar netting, the research of the asynchronous multisensor data fusion problem is more practical than that of the synchronous one. Through discussing the sequential approach, which is the classical asynchronous multisensor data fusion algorithm, a new algorithm based on distributed computation structure is proposed. The new algorithm can meet the requirement of real-time computation of netting fusion system, and is more practical for engineering compared with the classical sequential approach. Simulation results show the validity of the presented algorithm.展开更多
Error codes induced by M-ary modulation and modulation selection in network-based control systems are studied.It is the first time the issue of error codes induced by M-ary modulation is addressed in control field.In ...Error codes induced by M-ary modulation and modulation selection in network-based control systems are studied.It is the first time the issue of error codes induced by M-ary modulation is addressed in control field.In network-based control systems,error codes induced by noisy channel can significantly decrease the quality of control.To solve this problem,the network-based control system with delay and noisy channel is firstly modeled as an asynchronous dynamic system(ADS).Secondly,conditions of packet with error codes(PEC)loss rate by using M-ary modulation are obtained based on dynamic output feedback scheme.Thirdly,more importantly,the selection principle of M-ary modulation is proposed according to the measured signal-to-noise ratio(SNR)and conditions of PEC loss rate.Finally,system stability is analyzed and controller is designed through Lyapunov function and linear matrix inequality(LMI)scheme,and numerical simulations are made to demonstrate the effectiveness of the proposed scheme.展开更多
ECFD （erroneous cell tail drop）, a buffer management optimization strategy is suggested which can improve the utilization of buffer resources in satellite ATM （asynchronous transfer mode） networks. The strategy, i...ECFD （erroneous cell tail drop）, a buffer management optimization strategy is suggested which can improve the utilization of buffer resources in satellite ATM （asynchronous transfer mode） networks. The strategy, in which erroneous cells caused by satellite channel and the following cells that belong to the same PDU （protocol data Unit） are discarded, concerns non-real-time data services that use higher layer protocol for retransmission. Based on EPD （early packet drop） policy, mathematical models are established with and without ECTD. The numerical results show that ECTD would optimize buffer management and improve effective throughput （goodput）, and the increment of goodput is relative to the CER （cell error ratio） and the PDU length. The higher their values are, the greater the increment. For example, when the average PDU length values are 30 and 90, the improvement of goodput are respectively about 4% and 10%.展开更多
Today the cycle time of the product develop is requ ir ed to be shortened. At the same time the requirement of the customers becomes mo re and more diverse and complex. The capability of the develop unit is limited b ...Today the cycle time of the product develop is requ ir ed to be shortened. At the same time the requirement of the customers becomes mo re and more diverse and complex. The capability of the develop unit is limited b ecause of the existence of heterogeneous systems and distributed environments. I n this paper, we bring forward a new approach to solve the problem in product de velopment process. We also settle part key technologies in it. A great deal of information from all kinds of sources in the distributed develop ment process is interweaved. The solution to organize the workflow and manage th e information in the process is called for anxiously. We use a new approach that is asynchronous and synchronous coupling product development approach based on the network. The approach extends the develop process from the time axis. Then t he activities in the process are organized from the asynchronous and synchronous aspects. The state of every activity projects at the ASN (active semantic netwo rk). The ASN includes decision system, intelligent agent, user interface and net work. The ASN decides the types and states of the activities and deals with the couple relationship among them. The knowledge stored in ASN is open to all users through the relative interfaces. Every specialist keeps contact with their user s relying on collaborative platform implements CSCW (computer support collaborat ive work) that integrated product/process design and development. The lack of gl obal communication in product development process can be prevented in the most d egree. The key technologies that exist in the asynchronous and synchronous coupling pro duct develop approach include: integrated development structure, orderly organiz ation of information, transparent management of process, agile transfer of infor mation and rapid prototype. The development process can be completed quickly by these technologies. The technologies involve wide content. In this paper, we dis cuss some key technologies. We validate the approach by the projectrapid response manufacturing a pplication in the distributed environment. The expensive device, high technology and low using lead to RE (Rapid engineering) and RP (Rapid prototype) service a pplication by the network. RE and RP develop rapidly due to the accelerated prod uct development process. RE and RP application service platform is built in the project.展开更多
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Projects(61103011,61170261) supported by the National Natural Science Foundation of China
文摘Many energy efficiency asynchronous duty-cycle MAC(media access control) protocols have been proposed in recent years.However,in these protocols,wireless sensor nodes almost choose their wakeup time randomly during the operational cycle,which results in the packet delivery latency increased significantly on the multiple hops path.To reduce the packet delivery latency on multi-hop path and energy waste of the sender's idle listening,a new low latency routing-enhanced asynchronous duty-cycle MAC protocol was presented,called REA-MAC.In REA-MAC,each sensor node decided when it waked up to send the beacon based on cross-layer routing information.Furthermore,the sender adaptively waked up based on the relationship between the transmission request time and the wakeup time of its next hop node.The simulation results show that REA-MAC reduces delivery latency by 60% compared to RI-MAC and reduces 8.77% power consumption on average.Under heavy traffic,REA-MAC's throughput is 1.48 times of RI-MAC's.
文摘This paper presents partially asynchronous parallel simulation of continuous-system (PAPSoCS) and some approaches to the issues of its implementation on a multicomputer system. To guarantee the simulation results correct and speedup the simulation, the scheme for efficient PAPSoCS is proposed and the virtual topology star is constructed to match the path of message passing for solving algorithm-architecture adequation problem. Under the circumstances that messages frequently passed inter-processor are much shorter, typically within several 4 bytes, asynchronous communication mode is employed to reduce the communication ratio. Experiment results show that asynchronous parallel simulation has much higher efficiency than its synchronous counterpart.
基金Supported by National Natural Science Foundation of China(62033006,62203254)。
文摘We study distributed optimization problems over a directed network,where nodes aim to minimize the sum of local objective functions via directed communications with neighbors.Many algorithms are designed to solve it for synchronized or randomly activated implementation,which may create deadlocks in practice.In sharp contrast,we propose a fully asynchronous push-pull gradient(APPG) algorithm,where each node updates without waiting for any other node by using possibly delayed information from neighbors.Then,we construct two novel augmented networks to analyze asynchrony and delays,and quantify its convergence rate from the worst-case point of view.Particularly,all nodes of APPG converge to the same optimal solution at a linear rate of O(λ^(k)) if local functions have Lipschitz-continuous gradients and their sum satisfies the Polyak-?ojasiewicz condition(convexity is not required),where λ ∈(0,1) is explicitly given and the virtual counter k increases by one when any node updates.Finally,the advantage of APPG over the synchronous counterpart and its linear speedup efficiency are numerically validated via a logistic regression problem.
文摘鉴于农民因信息不对称导致农产品购销渠道不畅,设计开发了一种基于Ajax(Asynchronous JavaScript and XML)的多层体系结构的简单、高效的农产品信息服务平台系统。系统采用异步通信方式实现无刷新下动态页面局部数据更新;提供基于实例的信息发布方式;通过自动查询和嵌入手机短信实现信息的配对,从而使系统具有易用性、高效性、便捷性,利于平台的使用推广。
基金This project was supported by the National Natural Science Foundation of China (60274014)Doctor Foundation of China Education Ministry (20020487006).
文摘A kind of networked control system with network-induced delay and packet dropout, modeled on asynchronous dynamical systems was tested, and the integrity design of the networked control system with sensors failures and actuators failures was analyzed using hybrid systems technique based on the robust fault-tolerant control theory. The parametric expression of controller is given based on the feasible solution of linear matrix inequality. The simulation results are provided on the basis of detailed theoretical analysis, which further demonstrate the validity of the proposed schema.
文摘Due to the different data rates of the sensors and communication delays in the radar netting, the research of the asynchronous multisensor data fusion problem is more practical than that of the synchronous one. Through discussing the sequential approach, which is the classical asynchronous multisensor data fusion algorithm, a new algorithm based on distributed computation structure is proposed. The new algorithm can meet the requirement of real-time computation of netting fusion system, and is more practical for engineering compared with the classical sequential approach. Simulation results show the validity of the presented algorithm.
基金Project(61172022) supported by the National Natural Science Foundation of ChinaProject(GDW20151100010) supported by the State Administration of Foreign Experts Affairs of China
文摘Error codes induced by M-ary modulation and modulation selection in network-based control systems are studied.It is the first time the issue of error codes induced by M-ary modulation is addressed in control field.In network-based control systems,error codes induced by noisy channel can significantly decrease the quality of control.To solve this problem,the network-based control system with delay and noisy channel is firstly modeled as an asynchronous dynamic system(ADS).Secondly,conditions of packet with error codes(PEC)loss rate by using M-ary modulation are obtained based on dynamic output feedback scheme.Thirdly,more importantly,the selection principle of M-ary modulation is proposed according to the measured signal-to-noise ratio(SNR)and conditions of PEC loss rate.Finally,system stability is analyzed and controller is designed through Lyapunov function and linear matrix inequality(LMI)scheme,and numerical simulations are made to demonstrate the effectiveness of the proposed scheme.
文摘ECFD （erroneous cell tail drop）, a buffer management optimization strategy is suggested which can improve the utilization of buffer resources in satellite ATM （asynchronous transfer mode） networks. The strategy, in which erroneous cells caused by satellite channel and the following cells that belong to the same PDU （protocol data Unit） are discarded, concerns non-real-time data services that use higher layer protocol for retransmission. Based on EPD （early packet drop） policy, mathematical models are established with and without ECTD. The numerical results show that ECTD would optimize buffer management and improve effective throughput （goodput）, and the increment of goodput is relative to the CER （cell error ratio） and the PDU length. The higher their values are, the greater the increment. For example, when the average PDU length values are 30 and 90, the improvement of goodput are respectively about 4% and 10%.
文摘Today the cycle time of the product develop is requ ir ed to be shortened. At the same time the requirement of the customers becomes mo re and more diverse and complex. The capability of the develop unit is limited b ecause of the existence of heterogeneous systems and distributed environments. I n this paper, we bring forward a new approach to solve the problem in product de velopment process. We also settle part key technologies in it. A great deal of information from all kinds of sources in the distributed develop ment process is interweaved. The solution to organize the workflow and manage th e information in the process is called for anxiously. We use a new approach that is asynchronous and synchronous coupling product development approach based on the network. The approach extends the develop process from the time axis. Then t he activities in the process are organized from the asynchronous and synchronous aspects. The state of every activity projects at the ASN (active semantic netwo rk). The ASN includes decision system, intelligent agent, user interface and net work. The ASN decides the types and states of the activities and deals with the couple relationship among them. The knowledge stored in ASN is open to all users through the relative interfaces. Every specialist keeps contact with their user s relying on collaborative platform implements CSCW (computer support collaborat ive work) that integrated product/process design and development. The lack of gl obal communication in product development process can be prevented in the most d egree. The key technologies that exist in the asynchronous and synchronous coupling pro duct develop approach include: integrated development structure, orderly organiz ation of information, transparent management of process, agile transfer of infor mation and rapid prototype. The development process can be completed quickly by these technologies. The technologies involve wide content. In this paper, we dis cuss some key technologies. We validate the approach by the projectrapid response manufacturing a pplication in the distributed environment. The expensive device, high technology and low using lead to RE (Rapid engineering) and RP (Rapid prototype) service a pplication by the network. RE and RP develop rapidly due to the accelerated prod uct development process. RE and RP application service platform is built in the project.
