This paper is devoted to application of ordinary kriging method in Choghart north anomaly iron ore deposit in Yazd province, Iran. In order to estimate the deposit, 2329 input data gained from 26 boreholes were used. ...This paper is devoted to application of ordinary kriging method in Choghart north anomaly iron ore deposit in Yazd province, Iran. In order to estimate the deposit, 2329 input data gained from 26 boreholes were used. Fe grade was selected as the major regional variable on which the present research has focused. All of the available data were changed to 12.5 m composites so that statistical regularization could be reached. Studies indicated that iron grade input data had single-population characteristics. To carry out ordinary kriging, a spherical model was fitted over empirical variogram. Then the model was verified through cross validation method and proved to be valid with a coherence coefficient of 0.773 between the estimated and real data. Plotting the empirical variogram in different directions showed no geometric anisotropy for the deposit. To estimate the Iron grade, ordinary kriging method was used according to which, all of the exploitable blocks with dimensions 20 m x 20 m x 12.5 m were block esti- mated within the estimation space. Finally tonnage-grade curve has been drawn and reserve classified into measured, indicated and inferred.展开更多
There is an increasing demand on wireless communications in subway tunnels to provide video surveillance and sensory data for security,maintenance and train control,and to offer various communication or entertainment ...There is an increasing demand on wireless communications in subway tunnels to provide video surveillance and sensory data for security,maintenance and train control,and to offer various communication or entertainment services(e.g.,Internet,etc.) to passengers as well.The wireless channel in tunnels is quite unique due to the confined space and the waveguide effects.Therefore,modeling the radio channel characteristics in tunnels is critically important for communication systems design or optimization.This paper investigates the key radio channel characteristics of a subway tunnel at 2.4 GHz and 5 GHz,such as the path loss,root mean square(RMS) delay spread,channel stationarity,Doppler shift,and channel capacity.The field measurements show that channel characteristics in tunnels are highly location-dependent and there exist abundant components in Doppler shift domain.In the straight section of the subway tunnel,the measured path loss exponents are close to1.6,lower than that in free space.展开更多
Based on the analysis of the impact of Doppler shift to the railway dedicated mobile communication quality under the condition of high-speed mobility,this paper presents a Doppler shift measurement approach based on t...Based on the analysis of the impact of Doppler shift to the railway dedicated mobile communication quality under the condition of high-speed mobility,this paper presents a Doppler shift measurement approach based on the phase estimation of frequency correction channel(FCCH) which correctly reflects the time-varying characteristic of the channel with a testing system developed.The Doppler shift data under the high-speed condition is collected,processed,analyzed,and compared with the simulation results.The scientific laws of the Doppler shift distribution of radio channel under high-speed condition are obtained.These data and analysis are essential for the establishment of high-speed railway Doppler power spectrum model and the development of the key technology of antiDoppler shift.展开更多
基金the National Natural Science Foundation of China (Nos. 40772192 and 40372123)the Key Laboratory Project of Deep Rock Mechanics (No.PD1011)
文摘This paper is devoted to application of ordinary kriging method in Choghart north anomaly iron ore deposit in Yazd province, Iran. In order to estimate the deposit, 2329 input data gained from 26 boreholes were used. Fe grade was selected as the major regional variable on which the present research has focused. All of the available data were changed to 12.5 m composites so that statistical regularization could be reached. Studies indicated that iron grade input data had single-population characteristics. To carry out ordinary kriging, a spherical model was fitted over empirical variogram. Then the model was verified through cross validation method and proved to be valid with a coherence coefficient of 0.773 between the estimated and real data. Plotting the empirical variogram in different directions showed no geometric anisotropy for the deposit. To estimate the Iron grade, ordinary kriging method was used according to which, all of the exploitable blocks with dimensions 20 m x 20 m x 12.5 m were block esti- mated within the estimation space. Finally tonnage-grade curve has been drawn and reserve classified into measured, indicated and inferred.
基金supported in part by the NSFC project under grant No.61132003the Fundamental Research Funds for the Central Universities(2013JBZ002)the Ph.D.Program Foundation of Ministry of Education of China under grant No.20120009130002
文摘There is an increasing demand on wireless communications in subway tunnels to provide video surveillance and sensory data for security,maintenance and train control,and to offer various communication or entertainment services(e.g.,Internet,etc.) to passengers as well.The wireless channel in tunnels is quite unique due to the confined space and the waveguide effects.Therefore,modeling the radio channel characteristics in tunnels is critically important for communication systems design or optimization.This paper investigates the key radio channel characteristics of a subway tunnel at 2.4 GHz and 5 GHz,such as the path loss,root mean square(RMS) delay spread,channel stationarity,Doppler shift,and channel capacity.The field measurements show that channel characteristics in tunnels are highly location-dependent and there exist abundant components in Doppler shift domain.In the straight section of the subway tunnel,the measured path loss exponents are close to1.6,lower than that in free space.
基金Supported by the National Natural Science Foundation of China(No.U133420261222105)+1 种基金the Key Grant Project of Chinese Ministry of Education(No.313006)the Project of State Key Lab of Rail Traffic Control and Safety(No.RCS 2014ZT11)
文摘Based on the analysis of the impact of Doppler shift to the railway dedicated mobile communication quality under the condition of high-speed mobility,this paper presents a Doppler shift measurement approach based on the phase estimation of frequency correction channel(FCCH) which correctly reflects the time-varying characteristic of the channel with a testing system developed.The Doppler shift data under the high-speed condition is collected,processed,analyzed,and compared with the simulation results.The scientific laws of the Doppler shift distribution of radio channel under high-speed condition are obtained.These data and analysis are essential for the establishment of high-speed railway Doppler power spectrum model and the development of the key technology of antiDoppler shift.
