According to the basic requirements of underground mine personnel position systems and the working characteristics of active RFID tags,we studied the cause of concurrent collision of RFID tags and leak reading probabi...According to the basic requirements of underground mine personnel position systems and the working characteristics of active RFID tags,we studied the cause of concurrent collision of RFID tags and leak reading probability,by means of theoretical analysis and computation.The result shows that the probability of wireless collision increases linearly with an increase in the number of tags.The probability of collision and leak reading can be reduced by extending the working period of the duty cycle and using a backoff algorithm.In a practical application,a working schedule for available labels has been designed according to the requirement of the project.展开更多
Calculation of repeated observation data at the densified GPS monitoring network in northeastern area of Pamir together with data from IGS stations in the periphery of the area yielded the movement rate of more than 4...Calculation of repeated observation data at the densified GPS monitoring network in northeastern area of Pamir together with data from IGS stations in the periphery of the area yielded the movement rate of more than 40 GPS station sites in the area, and, hence, the recent crustal deformation rate pattern and time series of fiducial GPS stations in the area were obtained. The result indicates that the principal movement direction of the GPS station sites is NNW, basically diagonal to the strike of Tianshan fold belt, i.e. a normal compression occurs in the Tianshan region. The movement pattern near Jiashi and its southwestern zone is some different from that of station sites in their surrounding areas, indicating a certain relation of tectonic deformation in Jiashi area to seismic activity during last years. The movement rate of station sites in the periphery of Tarim basin less varies and its direction is basically consistent. It indicates less or basically no deformation within Tarim basin.展开更多
基金supported by the Fund of Coal Gas Sensing Technology and Early Warning Systems-Based Theory and Key Technology Research (No.50534050)
文摘According to the basic requirements of underground mine personnel position systems and the working characteristics of active RFID tags,we studied the cause of concurrent collision of RFID tags and leak reading probability,by means of theoretical analysis and computation.The result shows that the probability of wireless collision increases linearly with an increase in the number of tags.The probability of collision and leak reading can be reduced by extending the working period of the duty cycle and using a backoff algorithm.In a practical application,a working schedule for available labels has been designed according to the requirement of the project.
基金the state 973 project (G1998040703) and key research project of the State Science & Technology Ministry (96-913-07-03),China.
文摘Calculation of repeated observation data at the densified GPS monitoring network in northeastern area of Pamir together with data from IGS stations in the periphery of the area yielded the movement rate of more than 40 GPS station sites in the area, and, hence, the recent crustal deformation rate pattern and time series of fiducial GPS stations in the area were obtained. The result indicates that the principal movement direction of the GPS station sites is NNW, basically diagonal to the strike of Tianshan fold belt, i.e. a normal compression occurs in the Tianshan region. The movement pattern near Jiashi and its southwestern zone is some different from that of station sites in their surrounding areas, indicating a certain relation of tectonic deformation in Jiashi area to seismic activity during last years. The movement rate of station sites in the periphery of Tarim basin less varies and its direction is basically consistent. It indicates less or basically no deformation within Tarim basin.
