The performance of a cellular location system based on received signal strength difference （RSSD） is investigated. In the cellular location system, each mobile station needs to measure the signal strength transmitte...The performance of a cellular location system based on received signal strength difference （RSSD） is investigated. In the cellular location system, each mobile station needs to measure the signal strength transmitted by surrounding base stations, and sends its measurements to the service base station. Using the strength difference between the service base station and neighboring base stations, the position of a mobile station is estimated. The related Cramer-Rao lower bound （CRLB） on the location error of this method was derived, and numerical simulations are made to discuss the influences of the number of base stations, correlation coefficient of shadowing attenuation, and cell radius on CRLB. The results show that the CRLB is positively correlated with the standard deviation of shadowing attenuation and cell radius, but negatively correlated with the number of base stations and the correlation coefficient of shadowing attenuation. In addition, the CRLB results obtained in this paper were compared with those of the cellular location system based on received signal strength （RSS） measurements, which reveals that the former is more tight.展开更多
Acute hemorrhagic anemia can decrease blood flow and oxygen supply to brain, and affect its physiological function. While detecting changes in brain function in patients with acute hemorrhagic anemia is helpful for pr...Acute hemorrhagic anemia can decrease blood flow and oxygen supply to brain, and affect its physiological function. While detecting changes in brain function in patients with acute hemorrhagic anemia is helpful for preventing neurological complications and evaluating therapeutic effects, clinical changes in the nervous systems of these patients have not received much attention. In part, this is because current techniques can only indirectly detect changes in brain function following onset of anemia, which leads to lags between real changes in brain function and their detection.展开更多
Since 1983 it has been reported many times that the tensile strength of a liquid has a noticeable influence on incipient cavitation test[1,2,3].In this paper some results indicate the characters of tensile strength of...Since 1983 it has been reported many times that the tensile strength of a liquid has a noticeable influence on incipient cavitation test[1,2,3].In this paper some results indicate the characters of tensile strength of test wa- ter in different cavitation test facilities for example;characters in normal cavitation tunnel without free surface and in depression tank with free surface respectively.For getting a comparable and stable test result of cavitation inception it is important to know the tensile strength of test water and to keep it stable.展开更多
基金The National Natural Science Foundationof China (No.60472089)Southwest Jiaotong University Young Stuff Startup Research Project (No.2007Q134)
文摘The performance of a cellular location system based on received signal strength difference （RSSD） is investigated. In the cellular location system, each mobile station needs to measure the signal strength transmitted by surrounding base stations, and sends its measurements to the service base station. Using the strength difference between the service base station and neighboring base stations, the position of a mobile station is estimated. The related Cramer-Rao lower bound （CRLB） on the location error of this method was derived, and numerical simulations are made to discuss the influences of the number of base stations, correlation coefficient of shadowing attenuation, and cell radius on CRLB. The results show that the CRLB is positively correlated with the standard deviation of shadowing attenuation and cell radius, but negatively correlated with the number of base stations and the correlation coefficient of shadowing attenuation. In addition, the CRLB results obtained in this paper were compared with those of the cellular location system based on received signal strength （RSS） measurements, which reveals that the former is more tight.
基金supported by the Science and Technology Project of Shenzhen,No.JCY20120613170958482the First Affiliated Hospital of Shenzhen University Breeding Program,No.2012015
文摘Acute hemorrhagic anemia can decrease blood flow and oxygen supply to brain, and affect its physiological function. While detecting changes in brain function in patients with acute hemorrhagic anemia is helpful for preventing neurological complications and evaluating therapeutic effects, clinical changes in the nervous systems of these patients have not received much attention. In part, this is because current techniques can only indirectly detect changes in brain function following onset of anemia, which leads to lags between real changes in brain function and their detection.
基金This work was supported by Chinese National Natural Science Foundation by the Hydraulic and Hydroelectric Engineering Foundation of China.
文摘Since 1983 it has been reported many times that the tensile strength of a liquid has a noticeable influence on incipient cavitation test[1,2,3].In this paper some results indicate the characters of tensile strength of test wa- ter in different cavitation test facilities for example;characters in normal cavitation tunnel without free surface and in depression tank with free surface respectively.For getting a comparable and stable test result of cavitation inception it is important to know the tensile strength of test water and to keep it stable.
