To reduce the number of the level sets used in algorithm of constrained nonlinear systems via ellipsoidal techniques, according to the analysis of mathematics, searching algorithm is used for choosing the control inpu...To reduce the number of the level sets used in algorithm of constrained nonlinear systems via ellipsoidal techniques, according to the analysis of mathematics, searching algorithm is used for choosing the control input. Simulation shows that the number of level sets used for controlling is almost the same as that used in polytope techniques. Sub time optimal algorithm reduces the number of the level sets used in ellipsoidal techniques.展开更多
Power allocation is an important issue for Cognitive Radio Networks(CRNs),since it needs to consider the Quality of Service(QoS) for Secondary Users(SUs) while maintaining the interference power to Primary User(PU) be...Power allocation is an important issue for Cognitive Radio Networks(CRNs),since it needs to consider the Quality of Service(QoS) for Secondary Users(SUs) while maintaining the interference power to Primary User(PU) below the Interference Temperature(IT) threshold. In this paper, based on Euclidean projection, we propose a distributed power control algorithm with QoS requirements to minimise the total power consumption of SUs under the time-varying channel scenario. Considering the maximum transmit power constraints and the minimum signal to interference plus noise constraints for each SU, together with the IT constraints for each PU, the power allocation problem is transformed into a convex optimization problem without auxiliary variables, and is solved by the Lagrangian dual method with less information exchange.Simulation results demonstrate that the proposed scheme is superior to the Iterative Water-Filling Algorithm(IWFA).展开更多
Many industry processes can be described as Hammerstein-Wiener nonlinear systems. In this work, an improved constrained model predictive control algorithm is presented for Hammerstein-Wiener systems. In the new approa...Many industry processes can be described as Hammerstein-Wiener nonlinear systems. In this work, an improved constrained model predictive control algorithm is presented for Hammerstein-Wiener systems. In the new approach, the maximum and minimum of partial derivative for input and output nonlinearities are solved in the neighbourhood of the equilibrium. And several parameter-dependent Lyapunov functions, each one corresponding to a different vertex of polytopic descriptions models, are introduced to analyze the stability of Hammerstein-Wiener systems, but only one Lyapunov function is utilized to analyze system stability like the traditional method. Consequently, the conservation of the traditional quadratic stability is removed, and the terminal regions are enlarged. Simulation and field trial results show that the proposed algorithm is valid. It has higher control precision and shorter blowing time than the traditional approach.展开更多
We evaluated the pathogenicity of six strains 1. fumosorosea to determine their potential as biological control agents of A. ludens by performing bioassays under laboratory conditions （25 ± 2 ℃, 60± 5% R.H...We evaluated the pathogenicity of six strains 1. fumosorosea to determine their potential as biological control agents of A. ludens by performing bioassays under laboratory conditions （25 ± 2 ℃, 60± 5% R.H and 12：12 h L： D） exposing larvae and pupae to a concentration of 1 × 10^8 conidia per milliliter using three different methods： direct spraying, spray of soil and submerged for both instars. The results showed that direct spraying method Pfr-612 strain showed the highest mortality （47%） in pupae while for larvae was strain HIB-27 to 46%. Regarding spray of soil Pfr-612 strain showed the highest percentage of mortality for pupae and larvae with 45 and 57% mortality, respectively. Finally, for the submerged method in pupae HIB-27 strain showed 62% mortality whereas in larvae HIB-32 strain showed 46%. These results indicate that A. ludens is susceptible in at least two instars to L fumosorosea and make this fungus a promising agent for control of the Mexican fruit fly.展开更多
A reconfigurable, self-phase quadrifilar helical antenna was designed at BDS/GPS frequency band. The impedance, gain and directivity of the antenna were studied by HFSS based on FEM （finite element method） and exper...A reconfigurable, self-phase quadrifilar helical antenna was designed at BDS/GPS frequency band. The impedance, gain and directivity of the antenna were studied by HFSS based on FEM （finite element method） and experiment. Results show the beam width of the main lobe of the pattern can reach over 160° with the help of the load on the top of the antenna. And the power of the side-lobe level is very low. In addition, the quadrifitar helix antenna has excellent right-hand circular polarization performance with a beam width of 180°. Both single-frequency and double-frequency communications can be carried out by the antenna in the ranges between 1.2 and 1.8 GHz, with the bandwidth of each frequency about 60 MHz, the simulating and experimental results are nearly the same.展开更多
A first-order necessary condition for an infinite-dimensional nonlinear op-timization problem, which arises when the all-at-once method is employed to slove theoptimal control problems, is formulated and analyzed. Ope...A first-order necessary condition for an infinite-dimensional nonlinear op-timization problem, which arises when the all-at-once method is employed to slove theoptimal control problems, is formulated and analyzed. Operator constraint and simplebound on part of the variables are both considered. Based on this optimality condition,the trust-region subproblems are built, then the trust region method rnay be employedto deal with the optimizatiou problem in infinite-dimensional space.展开更多
文摘To reduce the number of the level sets used in algorithm of constrained nonlinear systems via ellipsoidal techniques, according to the analysis of mathematics, searching algorithm is used for choosing the control input. Simulation shows that the number of level sets used for controlling is almost the same as that used in polytope techniques. Sub time optimal algorithm reduces the number of the level sets used in ellipsoidal techniques.
基金supported by the National Natural Science Foundation of China under Grant No.61171079
文摘Power allocation is an important issue for Cognitive Radio Networks(CRNs),since it needs to consider the Quality of Service(QoS) for Secondary Users(SUs) while maintaining the interference power to Primary User(PU) below the Interference Temperature(IT) threshold. In this paper, based on Euclidean projection, we propose a distributed power control algorithm with QoS requirements to minimise the total power consumption of SUs under the time-varying channel scenario. Considering the maximum transmit power constraints and the minimum signal to interference plus noise constraints for each SU, together with the IT constraints for each PU, the power allocation problem is transformed into a convex optimization problem without auxiliary variables, and is solved by the Lagrangian dual method with less information exchange.Simulation results demonstrate that the proposed scheme is superior to the Iterative Water-Filling Algorithm(IWFA).
基金Project(61074074) supported by the National Natural Science Foundation,ChinaProject(KT2012C01J0401) supported by the Group Innovative Fund,China
文摘Many industry processes can be described as Hammerstein-Wiener nonlinear systems. In this work, an improved constrained model predictive control algorithm is presented for Hammerstein-Wiener systems. In the new approach, the maximum and minimum of partial derivative for input and output nonlinearities are solved in the neighbourhood of the equilibrium. And several parameter-dependent Lyapunov functions, each one corresponding to a different vertex of polytopic descriptions models, are introduced to analyze the stability of Hammerstein-Wiener systems, but only one Lyapunov function is utilized to analyze system stability like the traditional method. Consequently, the conservation of the traditional quadratic stability is removed, and the terminal regions are enlarged. Simulation and field trial results show that the proposed algorithm is valid. It has higher control precision and shorter blowing time than the traditional approach.
文摘We evaluated the pathogenicity of six strains 1. fumosorosea to determine their potential as biological control agents of A. ludens by performing bioassays under laboratory conditions （25 ± 2 ℃, 60± 5% R.H and 12：12 h L： D） exposing larvae and pupae to a concentration of 1 × 10^8 conidia per milliliter using three different methods： direct spraying, spray of soil and submerged for both instars. The results showed that direct spraying method Pfr-612 strain showed the highest mortality （47%） in pupae while for larvae was strain HIB-27 to 46%. Regarding spray of soil Pfr-612 strain showed the highest percentage of mortality for pupae and larvae with 45 and 57% mortality, respectively. Finally, for the submerged method in pupae HIB-27 strain showed 62% mortality whereas in larvae HIB-32 strain showed 46%. These results indicate that A. ludens is susceptible in at least two instars to L fumosorosea and make this fungus a promising agent for control of the Mexican fruit fly.
基金The research is supported by Shanghai Shuguang Plan Project （No： 15SG44） and NSFC of China （No： 51579143, 51379121 and 61304230） and China Postdoctoral Science Foundation （No： 2015M581585）.
文摘A reconfigurable, self-phase quadrifilar helical antenna was designed at BDS/GPS frequency band. The impedance, gain and directivity of the antenna were studied by HFSS based on FEM （finite element method） and experiment. Results show the beam width of the main lobe of the pattern can reach over 160° with the help of the load on the top of the antenna. And the power of the side-lobe level is very low. In addition, the quadrifitar helix antenna has excellent right-hand circular polarization performance with a beam width of 180°. Both single-frequency and double-frequency communications can be carried out by the antenna in the ranges between 1.2 and 1.8 GHz, with the bandwidth of each frequency about 60 MHz, the simulating and experimental results are nearly the same.
文摘A first-order necessary condition for an infinite-dimensional nonlinear op-timization problem, which arises when the all-at-once method is employed to slove theoptimal control problems, is formulated and analyzed. Operator constraint and simplebound on part of the variables are both considered. Based on this optimality condition,the trust-region subproblems are built, then the trust region method rnay be employedto deal with the optimizatiou problem in infinite-dimensional space.
