Magnetic sensors can be applied in vehicle recognition.Most of the existing vehicle recognition algorithms use one sensor node to measure a vehicle’s signature.However,vehicle speed variation and environmental distur...Magnetic sensors can be applied in vehicle recognition.Most of the existing vehicle recognition algorithms use one sensor node to measure a vehicle’s signature.However,vehicle speed variation and environmental disturbances usually cause errors during such a process.In this paper we propose a method using multiple sensor nodes to accomplish vehicle recognition.Based on the matching result of one vehicle’s signature obtained by different nodes,this method determines vehicle status and corrects signature segmentation.The co-relationship between signatures is also obtained,and the time offset is corrected by such a co-relationship.The corrected signatures are fused via maximum likelihood estimation,so as to obtain more accurate vehicle signatures.Examples show that the proposed algorithm can provide input parameters with higher accuracy.It improves the average accuracy of vehicle recognition from 94.0%to 96.1%,and especially the bus recognition accuracy from 77.6%to 92.8%.展开更多
In this study, finite element analysis based on an Ansoft Maxwell software was used to reveal the temperature stability of a magnet ring and the equivalent structural periodic permanent-magnet（PPM） focusing system. ...In this study, finite element analysis based on an Ansoft Maxwell software was used to reveal the temperature stability of a magnet ring and the equivalent structural periodic permanent-magnet（PPM） focusing system. It is found that with the temperature increasing, the decrease rate of magnetic induction peak（Bz）maxof single magnet ring is greater than that of remanence Brof magnet in the range from room temperature to 200 °C, however,the PPM focusing system do have the same temperature characteristics of permanent-magnet materials. It indicates that the magnetic temperature properties of the PPM system can be effectively controlled by adjusting the temperature properties of the magnets. Moreover, the higher permeability of the magnets indicates the less Hcb, giving rise to lower magnetic induction peak （Bz）′max： Finally, it should be noted that the magnetic orientation deviation angle θ（／15°） of permanent magnets has little effect on the focusing magnetic field of the PPM system at different temperatures and the temperature stability. The obtained results are beneficial to the design and selection of permanent magnets for PPM focusing system.展开更多
基金supported by the National Natural Science Foundation of China(No.61104164)the National High-Tech R&D Program(863)of China(No.2012AA112401)
文摘Magnetic sensors can be applied in vehicle recognition.Most of the existing vehicle recognition algorithms use one sensor node to measure a vehicle’s signature.However,vehicle speed variation and environmental disturbances usually cause errors during such a process.In this paper we propose a method using multiple sensor nodes to accomplish vehicle recognition.Based on the matching result of one vehicle’s signature obtained by different nodes,this method determines vehicle status and corrects signature segmentation.The co-relationship between signatures is also obtained,and the time offset is corrected by such a co-relationship.The corrected signatures are fused via maximum likelihood estimation,so as to obtain more accurate vehicle signatures.Examples show that the proposed algorithm can provide input parameters with higher accuracy.It improves the average accuracy of vehicle recognition from 94.0%to 96.1%,and especially the bus recognition accuracy from 77.6%to 92.8%.
基金financially supported by the National Natural Science Foundation of China (No. 61001120)
文摘In this study, finite element analysis based on an Ansoft Maxwell software was used to reveal the temperature stability of a magnet ring and the equivalent structural periodic permanent-magnet（PPM） focusing system. It is found that with the temperature increasing, the decrease rate of magnetic induction peak（Bz）maxof single magnet ring is greater than that of remanence Brof magnet in the range from room temperature to 200 °C, however,the PPM focusing system do have the same temperature characteristics of permanent-magnet materials. It indicates that the magnetic temperature properties of the PPM system can be effectively controlled by adjusting the temperature properties of the magnets. Moreover, the higher permeability of the magnets indicates the less Hcb, giving rise to lower magnetic induction peak （Bz）′max： Finally, it should be noted that the magnetic orientation deviation angle θ（／15°） of permanent magnets has little effect on the focusing magnetic field of the PPM system at different temperatures and the temperature stability. The obtained results are beneficial to the design and selection of permanent magnets for PPM focusing system.
