To extract the track parameters of a traffic object in traffic video and identify its motion behavior,a new method is proposed based on CamShift(Continuously Adaptive Mean Shift)and HMM(Hidden Markov Model).First,an o...To extract the track parameters of a traffic object in traffic video and identify its motion behavior,a new method is proposed based on CamShift(Continuously Adaptive Mean Shift)and HMM(Hidden Markov Model).First,an object entering the video scene is located and tracked by the CamShift based algorithm,then its track parameters are obtained.Next,the track parameters are processed to form the observation sequence of HMM,and the motion behavior modeling and probability evaluation are implemented based on HMM.At last,the behavior identification and behavior statistics of the tracked traffic object in video are achieved.Experiments show that this method can be used to sort and recognize the motion behavior of the traffic object by its corresponding behavior track,and to do some statistics or corresponding process schemes.展开更多
This article proposes a linear parameter varying （LPV） switching tracking control scheme for a flexible air-breathing hypersonic vehicle （FAHV）. First, a polytopic LPV model is constructed to represent the complex...This article proposes a linear parameter varying （LPV） switching tracking control scheme for a flexible air-breathing hypersonic vehicle （FAHV）. First, a polytopic LPV model is constructed to represent the complex nonlinear longitudinal model of the FAHV by using Jacobian linearization and tensor-product （T-P） model transformation approach. Second, for less conservative controller design purpose, the flight envelope is divided into four sub-regions and a non-fragile LPV controller is designed for each parameter sub-region. These non-fragile LPV controllers are then switched in order to guarantee the closed-loop FAHV system to be asymptotically stable and satisfy a specified performance criterion. The desired non-fragile LPV switching controller is found by solving a convex constraint problem which can be efficiently solved using available linear matrix inequality （LMI） techniques, and robust stability analysis of the closed-loop FAHV system is verified based on multiple Lypapunov functions （MLFs）. Finally, numerical simulations have demonstrated the effectiveness of the proposed approach.展开更多
In this research we try to investigate the optimum etching time for the tracks originate in (CR-39) solid state nuclear track detector after irradiated with alpha source (<sup>241</sup>Am) using three diff...In this research we try to investigate the optimum etching time for the tracks originate in (CR-39) solid state nuclear track detector after irradiated with alpha source (<sup>241</sup>Am) using three different etching techniques: the traditional method (water bath), microwaves and ultrasound devices. The track etching parameters: bulk etch rate (V<sub>B</sub>), track etch rate (V<sub>T</sub>), track etch rate ratio evaluates (V), critical angle (θ<sub>C</sub>), and etching efficiency (η) were calculated in this research. It’s seen that the optimum etching time was ranging with (60 - 150 min), (20 - 30 min) and (60 - 120 min) when etching with water bath, microwave and ultrasound respectively. Also we observed that the critical angle was (24.29) when etching CR-39 detector with microwave. This value is lower than the critical angles values for the detector etched with water bath or ultrasound;thus it can be the optimum magnitude because its decrease leads to increasing the number of the tracks appeared in the detector and the etching efficiency.展开更多
To achieve fast, smooth and accurate set point tracking in servo positioning systems, a parameterized design of nonlinear feedback controllers is presented, based on a so-called composite nonlinear feedback （CNF） co...To achieve fast, smooth and accurate set point tracking in servo positioning systems, a parameterized design of nonlinear feedback controllers is presented, based on a so-called composite nonlinear feedback （CNF） control technique. The controller designed here consists of a linear feedback part and a nonlinear part. The linear part is responsible for stability and fast response of the closed-loop system. The nonlinear part serves to increase the damping ratio of closed-loop poles as the controlled output approaches the target reference. The CNF control brings together the good points of both the small and the large damping ratio cases, by continuously scheduling the damping ratio of the dominant closed-loop poles and thus has the capability for superior transient performance, i.e. a fast output response with low overshoot. In the presence of constant disturbances, an integral action is included so as to remove the static bias. An explicitly parameterized controller is derived for servo positioning systems characterized by second-order model. Practical application in a micro hard disk drive servo system is then presented, together with some discussion of the rationale and characteristics of such design. Simulation and experimental results demonstrate the effectiveness of this control design methodology.展开更多
To realize the stabilization and the tracking of flight control for an air-breathing hypersonic cruise vehicle, the linearization of the longitudinal model under trimmed cruise condition is processed firstly. Furtherm...To realize the stabilization and the tracking of flight control for an air-breathing hypersonic cruise vehicle, the linearization of the longitudinal model under trimmed cruise condition is processed firstly. Furthermore, the flight control problem is formulated as a robust model tracking control problem. And then, based on the robust parametric approach, eigenstructure assignment and reference model tracking theory, a parametric optimization method for robust controller design is presented. The simulation results show the effectiveness of the proposed approach.展开更多
利用美国国家环境预测中心(National Centers for Environmental Prediction,NCEP)和国家大气研究中心(NCAR)联合研发的天气研究和预报模式(Weather Research and Forecasting Model,WRF),研究了不同积云对流参数化方案和微物理过程方案...利用美国国家环境预测中心(National Centers for Environmental Prediction,NCEP)和国家大气研究中心(NCAR)联合研发的天气研究和预报模式(Weather Research and Forecasting Model,WRF),研究了不同积云对流参数化方案和微物理过程方案对0514号台风"彩蝶"路径的影响。结果表明,积云对流参数化方案对台风路径影响较大,KF方案比BM方案能更好地模拟出台风路径;使用KF方案时,选择微物理方案比不选微物理方案对于台风路径有更好的模拟结果,其中,Ferrier、WSM6和Lin非常接近于实况;KF方案较好地模拟出副热带高压(简称副高)的西伸和东退的变化以及台风环流的风场分布和强度。展开更多
基金Sponsored by the National High Technology Research and Development Program of China(Grant No.2004AA742209)
文摘To extract the track parameters of a traffic object in traffic video and identify its motion behavior,a new method is proposed based on CamShift(Continuously Adaptive Mean Shift)and HMM(Hidden Markov Model).First,an object entering the video scene is located and tracked by the CamShift based algorithm,then its track parameters are obtained.Next,the track parameters are processed to form the observation sequence of HMM,and the motion behavior modeling and probability evaluation are implemented based on HMM.At last,the behavior identification and behavior statistics of the tracked traffic object in video are achieved.Experiments show that this method can be used to sort and recognize the motion behavior of the traffic object by its corresponding behavior track,and to do some statistics or corresponding process schemes.
基金co-supported by National Outstanding Youth Science Foundation(No.61125306)National Natural Science Foundation of Major Research Plan(Nos.91016004,61034002)+1 种基金Research Fund for the Doctoral Program of Higher Education of China(No.20110092110020)the Scientific Research Foundation of Graduate School of Southeast University(No.YBJJ1103)
文摘This article proposes a linear parameter varying （LPV） switching tracking control scheme for a flexible air-breathing hypersonic vehicle （FAHV）. First, a polytopic LPV model is constructed to represent the complex nonlinear longitudinal model of the FAHV by using Jacobian linearization and tensor-product （T-P） model transformation approach. Second, for less conservative controller design purpose, the flight envelope is divided into four sub-regions and a non-fragile LPV controller is designed for each parameter sub-region. These non-fragile LPV controllers are then switched in order to guarantee the closed-loop FAHV system to be asymptotically stable and satisfy a specified performance criterion. The desired non-fragile LPV switching controller is found by solving a convex constraint problem which can be efficiently solved using available linear matrix inequality （LMI） techniques, and robust stability analysis of the closed-loop FAHV system is verified based on multiple Lypapunov functions （MLFs）. Finally, numerical simulations have demonstrated the effectiveness of the proposed approach.
文摘In this research we try to investigate the optimum etching time for the tracks originate in (CR-39) solid state nuclear track detector after irradiated with alpha source (<sup>241</sup>Am) using three different etching techniques: the traditional method (water bath), microwaves and ultrasound devices. The track etching parameters: bulk etch rate (V<sub>B</sub>), track etch rate (V<sub>T</sub>), track etch rate ratio evaluates (V), critical angle (θ<sub>C</sub>), and etching efficiency (η) were calculated in this research. It’s seen that the optimum etching time was ranging with (60 - 150 min), (20 - 30 min) and (60 - 120 min) when etching with water bath, microwave and ultrasound respectively. Also we observed that the critical angle was (24.29) when etching CR-39 detector with microwave. This value is lower than the critical angles values for the detector etched with water bath or ultrasound;thus it can be the optimum magnitude because its decrease leads to increasing the number of the tracks appeared in the detector and the etching efficiency.
文摘To achieve fast, smooth and accurate set point tracking in servo positioning systems, a parameterized design of nonlinear feedback controllers is presented, based on a so-called composite nonlinear feedback （CNF） control technique. The controller designed here consists of a linear feedback part and a nonlinear part. The linear part is responsible for stability and fast response of the closed-loop system. The nonlinear part serves to increase the damping ratio of closed-loop poles as the controlled output approaches the target reference. The CNF control brings together the good points of both the small and the large damping ratio cases, by continuously scheduling the damping ratio of the dominant closed-loop poles and thus has the capability for superior transient performance, i.e. a fast output response with low overshoot. In the presence of constant disturbances, an integral action is included so as to remove the static bias. An explicitly parameterized controller is derived for servo positioning systems characterized by second-order model. Practical application in a micro hard disk drive servo system is then presented, together with some discussion of the rationale and characteristics of such design. Simulation and experimental results demonstrate the effectiveness of this control design methodology.
基金Sponsored by the Major Program of National Natural Science Foundation of China (Grant No.60710002)the Program for Changjiang Scholars and Innovative Research Team in University
文摘To realize the stabilization and the tracking of flight control for an air-breathing hypersonic cruise vehicle, the linearization of the longitudinal model under trimmed cruise condition is processed firstly. Furthermore, the flight control problem is formulated as a robust model tracking control problem. And then, based on the robust parametric approach, eigenstructure assignment and reference model tracking theory, a parametric optimization method for robust controller design is presented. The simulation results show the effectiveness of the proposed approach.
文摘利用美国国家环境预测中心(National Centers for Environmental Prediction,NCEP)和国家大气研究中心(NCAR)联合研发的天气研究和预报模式(Weather Research and Forecasting Model,WRF),研究了不同积云对流参数化方案和微物理过程方案对0514号台风"彩蝶"路径的影响。结果表明,积云对流参数化方案对台风路径影响较大,KF方案比BM方案能更好地模拟出台风路径;使用KF方案时,选择微物理方案比不选微物理方案对于台风路径有更好的模拟结果,其中,Ferrier、WSM6和Lin非常接近于实况;KF方案较好地模拟出副热带高压(简称副高)的西伸和东退的变化以及台风环流的风场分布和强度。
