There is a strong magnetic coupling between poloidal field coils of superconducting tokamak HT-7, especially between ohinic heating and vertical field coils. These coils are connected to individual power supply. The c...There is a strong magnetic coupling between poloidal field coils of superconducting tokamak HT-7, especially between ohinic heating and vertical field coils. These coils are connected to individual power supply. The control system for the plasma current and horizontal position control has been designed and showed satisfactory results with the feedback control of multivari- able feedforward-decoupling and var-parameter PID controller to simultaneously modulate power supplies. The design and analysls of the control system is presented.展开更多
Objective The purpose of the study was to evaluate the efficiency of the supine roll test(SRT)and alternative positional tests(APTs)including the bow and lean test(BLT),pseudo-spontaneous nystagmus(PSN),and lying down...Objective The purpose of the study was to evaluate the efficiency of the supine roll test(SRT)and alternative positional tests(APTs)including the bow and lean test(BLT),pseudo-spontaneous nystagmus(PSN),and lying down nystagmus(LDN)to identify the affected side in horizontal canal benign paroxysmal positional vertigo(HC-BPPV).Methods In our prospective study,we performed a testing profile(PSN,BLT,LDN,SRT)on 59 HC-BPPV patients using videonystagmography.We compared the accuracy and sensitivity of these tests in HC-BPPV lateralization.Data from 30 healthy patients were collected as the control group.Results When performing positional tests,the elicited nystagmus coinciding with Ewald’s second law was defined as a“positive response”.In 44 patients with geotropic nystagmus,the rates of positive response in LDN,PSN,and BLT were 22/44(50%),19/44(43%),and 18/44(41%),respectively,while in 15 patients with apogeotropic nystagmus,the positive response rates of these three tests were 10/15(66.7%),9/15(60%),and 4/15(27.00%),respectively.The sensitivity of LDN(54.38%)was higher than that of PSN(47.37%)and BLT(38.60%)but lower than that of SRT(89.47%).Notably,the accuracy rate of PSN(71.8%)was higher than that of the other APTs.In 6 patients with symmetrical nysgtamus during the roll test,5 patients showed a positive response in both LDN and BLT(83.34%),whereas 4 patients showed a positive response in PSN(66.67%).Conclusion All positional tests are helpful for determining the affected side of HC-BPPV,but SRT carries the highest accuracy of lateralization followed by PSN.展开更多
Based on multiple unmanned aerial vehicles(UAVs) flight at a constant altitude,a fault-tolerant cooperative localization algorithm against global positioning system(GPS) signal loss due to GPS receiver malfunction...Based on multiple unmanned aerial vehicles(UAVs) flight at a constant altitude,a fault-tolerant cooperative localization algorithm against global positioning system(GPS) signal loss due to GPS receiver malfunction is proposed.Contrast to the traditional means with single UAV,the proposed method is based on the use of inter-UAV relative range measurements against GPS signal loss and more suitable for the small-size and low-cost UAV applications.Firstly,for re-localizing an UAV with a malfunction in its GPS receiver,an algorithm which makes use of any other three healthy UAVs in the cooperative flight as the reference points for re-localization is proposed.Secondly,by using the relative ranges from the faulty UAV to the other three UAVs,its horizontal location can be determined after the GPS signal is lost.In order to improve an accuracy of the localization,a Kalman filter is further exploited to provide the estimated location of the UAV with the GPS signal loss.The Kalman filter calculates the variance of observations in terms of horizontal dilution of positioning(HDOP) automatically.Then,during each discrete computing time step,the best reference points are selected adaptively by minimizing the HDOP.Finally,two simulation examples in Matlab/Simulink environment with five UAVs in cooperative flight are shown to evaluate the effectiveness of the proposed method.展开更多
Receiver Autonomous Integrity Monitoring (RAIM) is a software algorithm available in some GPS receivers which gives an indication if the position solution given by the GPS receiver is suitable to use. The detail alg...Receiver Autonomous Integrity Monitoring (RAIM) is a software algorithm available in some GPS receivers which gives an indication if the position solution given by the GPS receiver is suitable to use. The detail algorithm of the parity space method of RAIM technique is presented. Using FDI and FDE methods, the simulations of RAIM performance have been done in three different phases independently with respect to the bias of the fault satellite. Case study of simulation results is discussed and each performance of RAIM is analyzed. According to the analysis of simulation results, the parity space method of RAIM can meet the integrity requirements for nonprecision, terminal and enroute flight phase. It also indicates that the results of performance of FDE are better than that of FDI.展开更多
文摘There is a strong magnetic coupling between poloidal field coils of superconducting tokamak HT-7, especially between ohinic heating and vertical field coils. These coils are connected to individual power supply. The control system for the plasma current and horizontal position control has been designed and showed satisfactory results with the feedback control of multivari- able feedforward-decoupling and var-parameter PID controller to simultaneously modulate power supplies. The design and analysls of the control system is presented.
基金the National Natural Science Foundation of China(No.81500794,No.81271078 and No.81500791)Scientific Research Project of Hubei Province Health and Family Planning(No.WJ2015MB062).
文摘Objective The purpose of the study was to evaluate the efficiency of the supine roll test(SRT)and alternative positional tests(APTs)including the bow and lean test(BLT),pseudo-spontaneous nystagmus(PSN),and lying down nystagmus(LDN)to identify the affected side in horizontal canal benign paroxysmal positional vertigo(HC-BPPV).Methods In our prospective study,we performed a testing profile(PSN,BLT,LDN,SRT)on 59 HC-BPPV patients using videonystagmography.We compared the accuracy and sensitivity of these tests in HC-BPPV lateralization.Data from 30 healthy patients were collected as the control group.Results When performing positional tests,the elicited nystagmus coinciding with Ewald’s second law was defined as a“positive response”.In 44 patients with geotropic nystagmus,the rates of positive response in LDN,PSN,and BLT were 22/44(50%),19/44(43%),and 18/44(41%),respectively,while in 15 patients with apogeotropic nystagmus,the positive response rates of these three tests were 10/15(66.7%),9/15(60%),and 4/15(27.00%),respectively.The sensitivity of LDN(54.38%)was higher than that of PSN(47.37%)and BLT(38.60%)but lower than that of SRT(89.47%).Notably,the accuracy rate of PSN(71.8%)was higher than that of the other APTs.In 6 patients with symmetrical nysgtamus during the roll test,5 patients showed a positive response in both LDN and BLT(83.34%),whereas 4 patients showed a positive response in PSN(66.67%).Conclusion All positional tests are helpful for determining the affected side of HC-BPPV,but SRT carries the highest accuracy of lateralization followed by PSN.
基金supported by the National Natural Science Foundation of China(60974146)the Natural Science and Engineering Research Council of Canada(NSERC)
文摘Based on multiple unmanned aerial vehicles(UAVs) flight at a constant altitude,a fault-tolerant cooperative localization algorithm against global positioning system(GPS) signal loss due to GPS receiver malfunction is proposed.Contrast to the traditional means with single UAV,the proposed method is based on the use of inter-UAV relative range measurements against GPS signal loss and more suitable for the small-size and low-cost UAV applications.Firstly,for re-localizing an UAV with a malfunction in its GPS receiver,an algorithm which makes use of any other three healthy UAVs in the cooperative flight as the reference points for re-localization is proposed.Secondly,by using the relative ranges from the faulty UAV to the other three UAVs,its horizontal location can be determined after the GPS signal is lost.In order to improve an accuracy of the localization,a Kalman filter is further exploited to provide the estimated location of the UAV with the GPS signal loss.The Kalman filter calculates the variance of observations in terms of horizontal dilution of positioning(HDOP) automatically.Then,during each discrete computing time step,the best reference points are selected adaptively by minimizing the HDOP.Finally,two simulation examples in Matlab/Simulink environment with five UAVs in cooperative flight are shown to evaluate the effectiveness of the proposed method.
文摘Receiver Autonomous Integrity Monitoring (RAIM) is a software algorithm available in some GPS receivers which gives an indication if the position solution given by the GPS receiver is suitable to use. The detail algorithm of the parity space method of RAIM technique is presented. Using FDI and FDE methods, the simulations of RAIM performance have been done in three different phases independently with respect to the bias of the fault satellite. Case study of simulation results is discussed and each performance of RAIM is analyzed. According to the analysis of simulation results, the parity space method of RAIM can meet the integrity requirements for nonprecision, terminal and enroute flight phase. It also indicates that the results of performance of FDE are better than that of FDI.