This paper concerns ultimately bounded output-feedback control problems for networked systems with unknown nonlinear dynamics. Sensor-to-observer signal transmission is facilitated over networks that has communication...This paper concerns ultimately bounded output-feedback control problems for networked systems with unknown nonlinear dynamics. Sensor-to-observer signal transmission is facilitated over networks that has communication constraints.These transmissions are carried out over an unreliable communication channel. In order to enhance the utilization rate of measurement data, a buffer-aided strategy is novelly employed to store historical measurements when communication networks are inaccessible. Using the neural network technique, a novel observer-based controller is introduced to address effects of signal transmission behaviors and unknown nonlinear dynamics.Through the application of stochastic analysis and Lyapunov stability, a joint framework is constructed for analyzing resultant system performance under the introduced controller. Subsequently, existence conditions for the desired output-feedback controller are delineated. The required parameters for the observerbased controller are then determined by resolving some specific matrix inequalities. Finally, a simulation example is showcased to confirm method efficacy.展开更多
In a crumbling tech hub near the marginal coastline,young Angolan developers,despite the challenges of unreliable Internet and dependence on foreign APIs(application programming interfaces),are tapping on donated lapt...In a crumbling tech hub near the marginal coastline,young Angolan developers,despite the challenges of unreliable Internet and dependence on foreign APIs(application programming interfaces),are tapping on donated laptops,debugging health apps that alert rural clinics of disease outbreaks.Their resilience and determination in the face of such obstacles are not just a source of innovation,but also of inspiration and hope.展开更多
为探索民机驾驶舱人机交互典型场景中人为差错发生的认知层面原因,运用人的排队网络信息加工模型(Queuing Network-Model Human Processor, QN-MHP)和人因可靠性方法对空速不可靠场景下的飞行员行为进行仿真研究。首先,通过设计任务及...为探索民机驾驶舱人机交互典型场景中人为差错发生的认知层面原因,运用人的排队网络信息加工模型(Queuing Network-Model Human Processor, QN-MHP)和人因可靠性方法对空速不可靠场景下的飞行员行为进行仿真研究。首先,通过设计任务及场景进行任务建模;然后,对模型中表示各脑区功能服务器的处理时间、处理容量及实体处理路径与差错概率赋值,进行24次仿真模拟;最后,通过设计模拟飞行试验,验证QN-MHP模型在民机驾驶舱人机交互研究中的可行性。结果表明,在空客A320机型空速不可靠处置任务中,飞行员在处置路径上易发生人为差错,在故障的识别、判断等关键节点也有少数差错发生,且任务过程中飞行员眼部利用率较高。研究表明,飞行员过高的用眼负荷是导致驾驶舱人机交互失效的原因之一,在未来驾驶舱人机交互流程设计及飞行训练中应予以重点关注。展开更多
Different from traditional aggregation method, the unreliable buffers are originally considered and a more general aggregation method is offered, in which not only the unreliable buffers are considered, but also the p...Different from traditional aggregation method, the unreliable buffers are originally considered and a more general aggregation method is offered, in which not only the unreliable buffers are considered, but also the probabilities of system states are obtained by a discrete model rather than the continuous flow model of unreliable manufacturing systems. The solution technique is offered to get the system sate probabilities. The method advances the traditional system aggregation techniques. Numerical results specify the extended aggregation method and also show that the unreliable limited buffers have a strong impact on the efficiency of the production lines.展开更多
This paper mainly investigates the connectivity of the unreliable sensor grid network. We consider an unreliable sensor grid network with mn nodes placed in a certain planar area A, and we assume that each node has in...This paper mainly investigates the connectivity of the unreliable sensor grid network. We consider an unreliable sensor grid network with mn nodes placed in a certain planar area A, and we assume that each node has independent failure probability p and has the same transmission range R. This paper presents a new method for calculating the connectivity probability of the network, which uses thorough mathematical methods to derive the relationship among the network connectivity probability, the probability that a node is ＂failed＂ （not active）, the numbers of node, and the node＇s transmission range in unreliable sensor networks. Our approach is more useful and efficient for given problem and conditions. Such as the numerical calculating results indicate that, for a 100×100 size sensot network, if node failure probability is bounded 0.5%, even if the transmission range is small （such as R = 10）, we can still maintain very high connectivity probability （reach 95.8%）. On the other hand, the simulation results show that building high connectivity probability is entirely possible on unreliable sensor grid networks.展开更多
The work deals with the development of analytical model of multichannel technical queuing system with unreliable servers and input memory where server failure flows and incoming request flows comply with Poissonian la...The work deals with the development of analytical model of multichannel technical queuing system with unreliable servers and input memory where server failure flows and incoming request flows comply with Poissonian laws, while the flows of failed facilities repairs and flows of incoming requests comply with exponential laws of probability distribution. Random process of system change-over is a Markovian process with continuous time and discrete states. Relations binding basic parameters and output characteristics of the system indicated are obtained as probabilities of system staying in the given moment in one of the possible states. The proposed model is the most generalized compared to some models known in literature which could be considered as special cases of the considered model.展开更多
基金supported in part by the National Natural Science Foundation of China (61933007,62273087,U22A2044,61973102,62073180)the Shanghai Pujiang Program of China (22PJ1400400)+1 种基金the Royal Society of the UKthe Alexander von Humboldt Foundation of Germany。
文摘This paper concerns ultimately bounded output-feedback control problems for networked systems with unknown nonlinear dynamics. Sensor-to-observer signal transmission is facilitated over networks that has communication constraints.These transmissions are carried out over an unreliable communication channel. In order to enhance the utilization rate of measurement data, a buffer-aided strategy is novelly employed to store historical measurements when communication networks are inaccessible. Using the neural network technique, a novel observer-based controller is introduced to address effects of signal transmission behaviors and unknown nonlinear dynamics.Through the application of stochastic analysis and Lyapunov stability, a joint framework is constructed for analyzing resultant system performance under the introduced controller. Subsequently, existence conditions for the desired output-feedback controller are delineated. The required parameters for the observerbased controller are then determined by resolving some specific matrix inequalities. Finally, a simulation example is showcased to confirm method efficacy.
文摘In a crumbling tech hub near the marginal coastline,young Angolan developers,despite the challenges of unreliable Internet and dependence on foreign APIs(application programming interfaces),are tapping on donated laptops,debugging health apps that alert rural clinics of disease outbreaks.Their resilience and determination in the face of such obstacles are not just a source of innovation,but also of inspiration and hope.
文摘为探索民机驾驶舱人机交互典型场景中人为差错发生的认知层面原因,运用人的排队网络信息加工模型(Queuing Network-Model Human Processor, QN-MHP)和人因可靠性方法对空速不可靠场景下的飞行员行为进行仿真研究。首先,通过设计任务及场景进行任务建模;然后,对模型中表示各脑区功能服务器的处理时间、处理容量及实体处理路径与差错概率赋值,进行24次仿真模拟;最后,通过设计模拟飞行试验,验证QN-MHP模型在民机驾驶舱人机交互研究中的可行性。结果表明,在空客A320机型空速不可靠处置任务中,飞行员在处置路径上易发生人为差错,在故障的识别、判断等关键节点也有少数差错发生,且任务过程中飞行员眼部利用率较高。研究表明,飞行员过高的用眼负荷是导致驾驶舱人机交互失效的原因之一,在未来驾驶舱人机交互流程设计及飞行训练中应予以重点关注。
基金Great Technology Innovation of Gansu Province,China (No.2GS063-A52-005-01)Natural Science Foundation of Gansu Province,China (No.3ZS062-B25-034)Research Item of Education Department of Gansu Province,China (No.0703-06)
文摘Different from traditional aggregation method, the unreliable buffers are originally considered and a more general aggregation method is offered, in which not only the unreliable buffers are considered, but also the probabilities of system states are obtained by a discrete model rather than the continuous flow model of unreliable manufacturing systems. The solution technique is offered to get the system sate probabilities. The method advances the traditional system aggregation techniques. Numerical results specify the extended aggregation method and also show that the unreliable limited buffers have a strong impact on the efficiency of the production lines.
基金Supported by the National Natural Science Foundation of China(90412012) the Natural Science Foundation of Guangdong Province andthe Post-doctoral Science Foundation of China
文摘This paper mainly investigates the connectivity of the unreliable sensor grid network. We consider an unreliable sensor grid network with mn nodes placed in a certain planar area A, and we assume that each node has independent failure probability p and has the same transmission range R. This paper presents a new method for calculating the connectivity probability of the network, which uses thorough mathematical methods to derive the relationship among the network connectivity probability, the probability that a node is ＂failed＂ （not active）, the numbers of node, and the node＇s transmission range in unreliable sensor networks. Our approach is more useful and efficient for given problem and conditions. Such as the numerical calculating results indicate that, for a 100×100 size sensot network, if node failure probability is bounded 0.5%, even if the transmission range is small （such as R = 10）, we can still maintain very high connectivity probability （reach 95.8%）. On the other hand, the simulation results show that building high connectivity probability is entirely possible on unreliable sensor grid networks.
文摘The work deals with the development of analytical model of multichannel technical queuing system with unreliable servers and input memory where server failure flows and incoming request flows comply with Poissonian laws, while the flows of failed facilities repairs and flows of incoming requests comply with exponential laws of probability distribution. Random process of system change-over is a Markovian process with continuous time and discrete states. Relations binding basic parameters and output characteristics of the system indicated are obtained as probabilities of system staying in the given moment in one of the possible states. The proposed model is the most generalized compared to some models known in literature which could be considered as special cases of the considered model.
