This paper presents a method of NTP-based time synchronization and a strategy of master-slave server structured time synchronization to ensure the test and control system of aeroengine to be time-synchronized. Based o...This paper presents a method of NTP-based time synchronization and a strategy of master-slave server structured time synchronization to ensure the test and control system of aeroengine to be time-synchronized. Based on time synchronization, the hierarchy and the integration of the measurement and control system of aeroengine are investigated. In result, our method is successfully applied for multiple front-end tests in a simulative altitude test facility of aeroengine.展开更多
It has been suggested that sick sinus syndrome, which is due to the dysfunction of the sinus node, may result from the sparser gap junctions and/or lower intrinsic frequencies of pacemaker cells that occur with aging....It has been suggested that sick sinus syndrome, which is due to the dysfunction of the sinus node, may result from the sparser gap junctions and/or lower intrinsic frequencies of pacemaker cells that occur with aging. Hence, in this paper, the synchronization mechanism of pacemaker cells that lie in the sinus node of the heart is examined using a modified Kuramoto phase model. Although each element always interacts with all the others in the Kuramoto phase model, in the proposed model, each element interacts only with the neighbors over a certain time (called the interaction time) during Phase 4 of the action potential. The pacemaker cell elements are arranged on a square lattice, and each element connects with the elements surrounding it. The results indicate that the diversity of intrinsic frequencies of pacemaker cells may be necessary for synchronization. Moreover, increasing the proportion of invalid connections causes the elements to take more time to synchronize until eventually they do not synchronize at all, and decreasing the intrinsic frequencies of the elements prevents them from synchronizing. Probably these elucidate the cause of sick sinus syndrome.展开更多
The researchers who study the local area network( LAN) eXtension for instrumentation( LXI) instrument are pursuing instrument's high-precision synchronization. In the paper,three synchronization modes were discuss...The researchers who study the local area network( LAN) eXtension for instrumentation( LXI) instrument are pursuing instrument's high-precision synchronization. In the paper,three synchronization modes were discussed which were clock synchronization, trigger synchronization, and response synchronization. Synchronous process between LXI instruments was analyzed and each time factor affecting the synchronization accuracy was discussed. On the basis of the analysis,it can be found that delay trigger plays an important role in the network testing system's synchronization. Delay trigger can produce an additional time interval to correct the difference of each LXI instrument's response time. Then,a method to realize the delay trigger was introduced. Delay time can be adjustable according to the actual demand. Finally,synchronization accuracy of network testing system can reach nanoseconds.展开更多
This paper considers the case of smart antennas and multiple inputs multiple outputs (MIMO) systems, suited for the radio access of 3G mobile communications, involving two-dimensional spatio-temporal signal processing...This paper considers the case of smart antennas and multiple inputs multiple outputs (MIMO) systems, suited for the radio access of 3G mobile communications, involving two-dimensional spatio-temporal signal processing and two-dwell procedures. The main novelty of our work is twofold: first, a two-dwell acquisition technique is here performed to save the mean acquisition time versus one-dwell acquisition techniques;sec-ond, the searching procedure is driven from the estimates of the local signal-to-interference-plus-noise ratio, reducing again the mean acquisition time. Some examples of application to the detection of 3G communication signals in typical mobile scenarios are provided and we have verified the effectiveness of the analyzed spatio-temporal two-dwell procedures. The presented technique seems to constitute a promising tool for analytic setting of near optimum spatio-temporal acquisition testing procedures based on serial search/veri-fication modes.展开更多
A new dual-actuator fatigue loading system of wind turbine blades was designed.Compared with the traditional pendulum loading mode,the masses in this system only moved linearly along the loading direction to increase ...A new dual-actuator fatigue loading system of wind turbine blades was designed.Compared with the traditional pendulum loading mode,the masses in this system only moved linearly along the loading direction to increase the exciting force.However,the two actuators and the blade constituted a complicated non-linear energy transferring system,which led to the non-synchronization of actuators.On-site test results showed that the virtual spindle synchronous strategy commonly used in synchronous control was undesirable and caused the instability of the blade’s amplitude eventually.A cross-coupled control strategy based on the active disturbance rejection algorithm was proposed.Firstly,a control system model was built according to the synchronization error and tracking error.Furthermore,based on arranging the transition process,estimating the system state and error feedback,and compensating disturbance,an active disturbance rejection controller was designed by adopting the optimal control function.Finally,on-site test results showed that the cross-coupled control strategy based on the active disturbance rejection algorithm could ensure the synchronization of two actuators.The maximum speed synchronization error of the two motors was less than 16 RPM,the displacement synchronization error of the two actuators was less than 0.25 mm and approaching zero after 4 seconds,and the peak value of vibration of the blade was less than 5 mm,which satisfied the fatigue test requirement.展开更多
With a random sample of 10 JCR(Science) subject areas it is shown that the 2-year and the 5-year impact factor of journals lead statistically to the same ranking per category. Yet in a majority of cases, the 5-year im...With a random sample of 10 JCR(Science) subject areas it is shown that the 2-year and the 5-year impact factor of journals lead statistically to the same ranking per category. Yet in a majority of cases, the 5-year impact factor is larger than the 2-year one.展开更多
This study proposes a recoverable stress testing algorithm (RSTA) for such special devices as compression/decom-pression card and encryption/decryption card. It uses a chaos function to generate a random sequence, and...This study proposes a recoverable stress testing algorithm (RSTA) for such special devices as compression/decom-pression card and encryption/decryption card. It uses a chaos function to generate a random sequence, and then, according to the random sequence, generates an effective command sequence. The dispatch of command obeys a special schedule strategy we designed for such devices, i.e., the commands are sent according to the command sequence, and the complete commands are put in a buffer for further result check. RSTA is used to test the HIFN compression acceleration card SAICHI-1000. Test results show that RSTA can make the card work continuously and adequately.展开更多
文摘This paper presents a method of NTP-based time synchronization and a strategy of master-slave server structured time synchronization to ensure the test and control system of aeroengine to be time-synchronized. Based on time synchronization, the hierarchy and the integration of the measurement and control system of aeroengine are investigated. In result, our method is successfully applied for multiple front-end tests in a simulative altitude test facility of aeroengine.
文摘It has been suggested that sick sinus syndrome, which is due to the dysfunction of the sinus node, may result from the sparser gap junctions and/or lower intrinsic frequencies of pacemaker cells that occur with aging. Hence, in this paper, the synchronization mechanism of pacemaker cells that lie in the sinus node of the heart is examined using a modified Kuramoto phase model. Although each element always interacts with all the others in the Kuramoto phase model, in the proposed model, each element interacts only with the neighbors over a certain time (called the interaction time) during Phase 4 of the action potential. The pacemaker cell elements are arranged on a square lattice, and each element connects with the elements surrounding it. The results indicate that the diversity of intrinsic frequencies of pacemaker cells may be necessary for synchronization. Moreover, increasing the proportion of invalid connections causes the elements to take more time to synchronize until eventually they do not synchronize at all, and decreasing the intrinsic frequencies of the elements prevents them from synchronizing. Probably these elucidate the cause of sick sinus syndrome.
基金Sino-German Joint Research Project of the Sino-German Center for Science(No.GZ817)the Fundamental Research Funds for the Central Universities,China(No.ZYGX2012 J090)National Natural Science Foundation of China(No.61271035)
文摘The researchers who study the local area network( LAN) eXtension for instrumentation( LXI) instrument are pursuing instrument's high-precision synchronization. In the paper,three synchronization modes were discussed which were clock synchronization, trigger synchronization, and response synchronization. Synchronous process between LXI instruments was analyzed and each time factor affecting the synchronization accuracy was discussed. On the basis of the analysis,it can be found that delay trigger plays an important role in the network testing system's synchronization. Delay trigger can produce an additional time interval to correct the difference of each LXI instrument's response time. Then,a method to realize the delay trigger was introduced. Delay time can be adjustable according to the actual demand. Finally,synchronization accuracy of network testing system can reach nanoseconds.
文摘This paper considers the case of smart antennas and multiple inputs multiple outputs (MIMO) systems, suited for the radio access of 3G mobile communications, involving two-dimensional spatio-temporal signal processing and two-dwell procedures. The main novelty of our work is twofold: first, a two-dwell acquisition technique is here performed to save the mean acquisition time versus one-dwell acquisition techniques;sec-ond, the searching procedure is driven from the estimates of the local signal-to-interference-plus-noise ratio, reducing again the mean acquisition time. Some examples of application to the detection of 3G communication signals in typical mobile scenarios are provided and we have verified the effectiveness of the analyzed spatio-temporal two-dwell procedures. The presented technique seems to constitute a promising tool for analytic setting of near optimum spatio-temporal acquisition testing procedures based on serial search/veri-fication modes.
基金the National Key R&D Program of China,Grant No.2018YFB1501203Meanwhile,this research was funded by the Natural Science Foundation of Shandong,Grant No.ZR2019MEE076And the work in this paper has partly received funding from the National Key R&D Program of Shandong,Grant No.2019GGX104001.
文摘A new dual-actuator fatigue loading system of wind turbine blades was designed.Compared with the traditional pendulum loading mode,the masses in this system only moved linearly along the loading direction to increase the exciting force.However,the two actuators and the blade constituted a complicated non-linear energy transferring system,which led to the non-synchronization of actuators.On-site test results showed that the virtual spindle synchronous strategy commonly used in synchronous control was undesirable and caused the instability of the blade’s amplitude eventually.A cross-coupled control strategy based on the active disturbance rejection algorithm was proposed.Firstly,a control system model was built according to the synchronization error and tracking error.Furthermore,based on arranging the transition process,estimating the system state and error feedback,and compensating disturbance,an active disturbance rejection controller was designed by adopting the optimal control function.Finally,on-site test results showed that the cross-coupled control strategy based on the active disturbance rejection algorithm could ensure the synchronization of two actuators.The maximum speed synchronization error of the two motors was less than 16 RPM,the displacement synchronization error of the two actuators was less than 0.25 mm and approaching zero after 4 seconds,and the peak value of vibration of the blade was less than 5 mm,which satisfied the fatigue test requirement.
基金supported by the National Natural Science Foundation of China(Grant No.70673019)
文摘With a random sample of 10 JCR(Science) subject areas it is shown that the 2-year and the 5-year impact factor of journals lead statistically to the same ranking per category. Yet in a majority of cases, the 5-year impact factor is larger than the 2-year one.
基金the Hi-Tech Research and Development Pro-gram (863) of China (No. 2006AA01Z431)the Giant Project of Zhejiang Province, China (No. 2006C11105)
文摘This study proposes a recoverable stress testing algorithm (RSTA) for such special devices as compression/decom-pression card and encryption/decryption card. It uses a chaos function to generate a random sequence, and then, according to the random sequence, generates an effective command sequence. The dispatch of command obeys a special schedule strategy we designed for such devices, i.e., the commands are sent according to the command sequence, and the complete commands are put in a buffer for further result check. RSTA is used to test the HIFN compression acceleration card SAICHI-1000. Test results show that RSTA can make the card work continuously and adequately.
