For a class of linear discrete-time systems that is subject to randomly occurred networked packet loss in industrial cyber physical systems, a novel robust model predictive control method with active compensation mech...For a class of linear discrete-time systems that is subject to randomly occurred networked packet loss in industrial cyber physical systems, a novel robust model predictive control method with active compensation mechanism was proposed. The probability distribution of packet loss is described as the Bernoulli distributed white sequences. By using the Lyapunov stability theory, the existing sufficient conditions of the controller are derived from solving a group of linear matrix inequalities. Moreover, dropout-rate with uncertainty and unknown dropout-rate are also considered, which can greatly reduce the conservativeness of the controller. The designed robust model predictive control method not only efficiently eliminates the negative effects of the networked data loss in industrial cyber physical systems but also ensures the stability of closed-loop system. Two examples were provided to illustrate the superiority and effectiveness of the proposed method.展开更多
Time delay or round trip time (RTT) is an important parameter in the model of Internet congestion control. On the one hand, the delay may induce oscillation via the Hopf bifurcation. In the present paper, a congestion...Time delay or round trip time (RTT) is an important parameter in the model of Internet congestion control. On the one hand, the delay may induce oscillation via the Hopf bifurcation. In the present paper, a congestion control model of n dimensions is considered to study the delay-induced oscillation. By linear analysis of the n-dimensional system, the critical delay for the Hopf bifurcation is obtained. To describe the relation between the delay and oscillation analytically, the method of multiple scales (MMS) is employed to obtain the bifurcating periodic solution. On the other hand, it can be understood that the oscillation will increase the risk of congestion for the network system. To avoid the congestion derived from the oscillation, a new control scheme is proposed by perturbing the delay periodically. Particularly, according to our study, it is possible to control the oscillation by perturbing only one of the n delays. This provides a practical scheme for the oscillation control in the real network system. By MMS, the strengths of the perturbations are predicted analytically such that the oscillation disappears. To give an example, an eight-dimensional model is studied in detail. The analytical results are in good agreement with the numerical simulations.展开更多
To enhance the communication quality of Open Flow controlled all-optical networks,an optical signal-to-noise ratio comprehensive-awareness(OSNR-CA) model based lightpath control scheme is proposed.This approach transf...To enhance the communication quality of Open Flow controlled all-optical networks,an optical signal-to-noise ratio comprehensive-awareness(OSNR-CA) model based lightpath control scheme is proposed.This approach transforms main physical-layer optical impairments into OSNR value,and takes this comprehensive OSNR value of the optical signal along the lightpath into consideration,when establishing the lightpath for the connection request using OpenFlow protocol.Moreover,the proposed scheme makes full advantages of the OSNR monitoring function in each node,and assigns the lightpath according to the comprehensive-OSNR value by extending messages of Open Flow protocol,in order to guarantee the reliable establishment of the lightpath.The simulation results show that the proposed scheme has better performance in terms of packet loss rate and lightpath establishment time.展开更多
基金Project(61673199)supported by the National Natural Science Foundation of ChinaProject(ICT1800400)supported by the Open Research Project of the State Key Laboratory of Industrial Control Technology,Zhejiang University,China
文摘For a class of linear discrete-time systems that is subject to randomly occurred networked packet loss in industrial cyber physical systems, a novel robust model predictive control method with active compensation mechanism was proposed. The probability distribution of packet loss is described as the Bernoulli distributed white sequences. By using the Lyapunov stability theory, the existing sufficient conditions of the controller are derived from solving a group of linear matrix inequalities. Moreover, dropout-rate with uncertainty and unknown dropout-rate are also considered, which can greatly reduce the conservativeness of the controller. The designed robust model predictive control method not only efficiently eliminates the negative effects of the networked data loss in industrial cyber physical systems but also ensures the stability of closed-loop system. Two examples were provided to illustrate the superiority and effectiveness of the proposed method.
基金supported by the State Key Program of National Natural Science Foundation of China (Grant No. 11032009)Shanghai Leading Academic Discipline Project (Grant No. B302)
文摘Time delay or round trip time (RTT) is an important parameter in the model of Internet congestion control. On the one hand, the delay may induce oscillation via the Hopf bifurcation. In the present paper, a congestion control model of n dimensions is considered to study the delay-induced oscillation. By linear analysis of the n-dimensional system, the critical delay for the Hopf bifurcation is obtained. To describe the relation between the delay and oscillation analytically, the method of multiple scales (MMS) is employed to obtain the bifurcating periodic solution. On the other hand, it can be understood that the oscillation will increase the risk of congestion for the network system. To avoid the congestion derived from the oscillation, a new control scheme is proposed by perturbing the delay periodically. Particularly, according to our study, it is possible to control the oscillation by perturbing only one of the n delays. This provides a practical scheme for the oscillation control in the real network system. By MMS, the strengths of the perturbations are predicted analytically such that the oscillation disappears. To give an example, an eight-dimensional model is studied in detail. The analytical results are in good agreement with the numerical simulations.
基金supported by the National High Technical Research and Development Program of China(863 Program)(No.2012AA050804)
文摘To enhance the communication quality of Open Flow controlled all-optical networks,an optical signal-to-noise ratio comprehensive-awareness(OSNR-CA) model based lightpath control scheme is proposed.This approach transforms main physical-layer optical impairments into OSNR value,and takes this comprehensive OSNR value of the optical signal along the lightpath into consideration,when establishing the lightpath for the connection request using OpenFlow protocol.Moreover,the proposed scheme makes full advantages of the OSNR monitoring function in each node,and assigns the lightpath according to the comprehensive-OSNR value by extending messages of Open Flow protocol,in order to guarantee the reliable establishment of the lightpath.The simulation results show that the proposed scheme has better performance in terms of packet loss rate and lightpath establishment time.
