Deformation modulus is the important parameter in stability analysis of tunnels, dams and mining struc- tures. In this paper, two predictive models including Mamdani fuzzy system （MFS） and multivariable regression a...Deformation modulus is the important parameter in stability analysis of tunnels, dams and mining struc- tures. In this paper, two predictive models including Mamdani fuzzy system （MFS） and multivariable regression analysis （MVRA） were developed to predict deformation modulus based on data obtained from dilatometer tests carried out in Bakhtiary dam site and additional data collected from longwall coal mines. Models inputs were considered to be rock quality designation, overburden height, weathering, unconfined compressive strength, bedding inclination to core axis, joint roughness coefficient and fill thickness. To control the models performance, calculating indices such as root mean square error （RMSE）, variance account for （VAF） and determination coefficient （R^2） were used. The MFS results show the significant prediction accuracy along with high performance compared to MVRA results. Finally, the sensitivity analysis of MFS results shows that the most and the least effective parameters on deformation modulus are weatherin~ and overburden height, respectively.展开更多
The ability to speak two languages in the non-English-speaking countries is a remarkable achievement. There is a good reason to believe that bilingualism is the norm for the majority of people in the world, because 70...The ability to speak two languages in the non-English-speaking countries is a remarkable achievement. There is a good reason to believe that bilingualism is the norm for the majority of people in the world, because 70% of the earth＇s population are supposed to be bilingual or multilingual. Our purpose of the study was to determine the participants＇ awareness of using true and false cognate words of L 1 （the first language） ＆ L2 （the second language） in learning English. Three hundred and eighty-five selected people from 3,789 statistical population participated in 2014--2015 at three levels of A.D., B.A., and M.A. of Islamic Azad University as well as teachers of English in English educational institutions in Zanjan （Iran）. Each educational level was considered as one category with the total sample calculated by using Kokran Formula, and the amount of each category was determined by using appropriate proportion and randomized categorical sampling method. The participants＇ age was between from 18 to 52, with a mean age of 29 years. The materials were 45 words of true and false cognate＇s words from 500 words by doing CVR （content validity ratio） and CVI （content validity index） （Lawshe＇s table with the index of 88% and 82% respectively） for being reliable and valid. ANOVA （Analysis of variance） was used for studying the effect of educational level on the rate of awareness. In other words, the awareness level has been compared in different educational levels. The results of Dankan test show that： There is no significant difference between the awareness of A.D., B.A., and M.A. levels, but there is a significant difference between the level of awareness of teachers group and the other groups （in true cognate words） and for false cognate words, there is no significant difference between the level of awareness of the four groups in this regard.展开更多
Orthogonal Frequency Division Multiplexing(OFDM) is an effective technique to deal with a frequency selective channel since it can convert the channel into some flat fading subchannels.However,very different output SN...Orthogonal Frequency Division Multiplexing(OFDM) is an effective technique to deal with a frequency selective channel since it can convert the channel into some flat fading subchannels.However,very different output SNR values of the subchannels will lead to poor bit error performance when a linear equalizer and Equal Bit Allocation(EBA) are adopted in OFDM systems.So,we proposed three novel nonlinear Joint Transceiver(JT) schemes based on Zero-Forcing(ZF) criterion and Minimum Mean Square Error(MMSE) criterion respectively,which can transform all subchannels of an OFDM system into subchannels with identical channel gain.Thus,EBA is equivalent to the Optimum Bit Allocation(OBA) for these subchannels.Numerical analysis helps us to obtain the theoretical approximate BER values of the JT scheme.Simulation results verify the numerical analysis and confirm that the performance of our proposed JT scheme greatly outperforms the traditional linear equalizer with EBA at moderate and high SNR values.展开更多
The accuracy of daily mean 2 meter air temperatures from five reanalyses are assessed against in-situ observations from Automatic Weather Stations in East Antarctica for 2005 to 2008. The five reanalyses all explain m...The accuracy of daily mean 2 meter air temperatures from five reanalyses are assessed against in-situ observations from Automatic Weather Stations in East Antarctica for 2005 to 2008. The five reanalyses all explain more than 70% of the average variance, and have annual root mean square errors （RMSE） between 3.4 and 6.9℃. The NOAA reanalyses, NCEP-1, NCEP-2 and 20CRv2, have cool biases of 2.5, 1.4 and 1.5℃, respectively. The ERA Interim and JCDAS reanalyses have warm biases of 1.7 and 2.0℃. All reanalyses generally perform better in the austral spring and worse in winter and autumn. They also show the best performance at an inland plateau site at 2800 m elevation, but are worst at Dome A, the summit of the East Antarctic ice sheet. In general, ERA Interim is superior to the other reanalyses, probably because of its 4D assimilation scheme. The three NOAA reanalyses perform worst; Their assimilation scheme is more constrained by limited observations and 20CRy2 has less input data, assimilating only surface pressure observations. Despite deficiencies and limitations, the reanalyses are still powerful tools for climate studies in the Antarctic region. However, more in-situ observations are required, especially from the vast interior of Antarctica.展开更多
This paper presents an innovative and low-cost approach for nondestructive fruit quality analysis. The specialized optical fiber sensor developed and presented in this paper used a monochromatic wavelength, rather tha...This paper presents an innovative and low-cost approach for nondestructive fruit quality analysis. The specialized optical fiber sensor developed and presented in this paper used a monochromatic wavelength, rather than a broad spectrum, to measure the intact carambola （star fruit） intrinsic quality, namely pH and firmness. The main objective of this research was to investigate the two optical fiber sensors used in this work, namely, the optical fiber red system （OF-RS） that operated with the peak sensitivity at 635 nm and the optical fiber near the infrared spectroscopy system （OF-NIRS） that operated with the peak sensitivity at 880nm. Both systems showed good accuracy in the pH and firmness measurement of the intact carambola with the correlation coefficient R over 0.75, and the measurement results were comparable with those of the commercial spectrometer. The best measurement results were obtained using OF-RS （pH： R = 0.876; the root mean square error （RMSE） = 0.211 pH; firmness： R = 0.872; RMSE = 0.909 kgf）.展开更多
An improved method is proposed to simulate the scintillation introduced by the turbulence, based on the finite Markov state model. As a contrast to the literatures, uniformly distributed variables take place during a ...An improved method is proposed to simulate the scintillation introduced by the turbulence, based on the finite Markov state model. As a contrast to the literatures, uniformly distributed variables take place during a certain state, which contributes to equivalent simulation of the intensity fluctuations with fewer states than the traditional Markov model. It's also discovered that the proposed Markov model with 20 states provides a satisfactory approximation to the experimental results in the auto-covariance analysis. Moreover, the outage probability and mean fading time are more accurate than those of the traditional Markov model with equivalent states.展开更多
This paper analyzes performance of optimal channel estimation and multiuser detection(MUD) in a block-fading code-division multiple-access (CDMA) channel on the assumptions of randomspreading and large-system limit,by...This paper analyzes performance of optimal channel estimation and multiuser detection(MUD) in a block-fading code-division multiple-access (CDMA) channel on the assumptions of randomspreading and large-system limit,by using the replica method developed in statistical mechanics.The authors find that the asymptotic spectral efficiency of the linear minimum mean-squared error(LMMSE) MUD which was proposed and analyzed by Evans and Tse in 2000 is indistinguishable fromthat of the optimal MUD for small system loads.Our results imply that performance of MUD scarcelyimproves even if one spends more computational cost than that of the LMMSE MUD,i.e.,at most thecube of the number of users,on the above-described conditions.展开更多
文摘Deformation modulus is the important parameter in stability analysis of tunnels, dams and mining struc- tures. In this paper, two predictive models including Mamdani fuzzy system （MFS） and multivariable regression analysis （MVRA） were developed to predict deformation modulus based on data obtained from dilatometer tests carried out in Bakhtiary dam site and additional data collected from longwall coal mines. Models inputs were considered to be rock quality designation, overburden height, weathering, unconfined compressive strength, bedding inclination to core axis, joint roughness coefficient and fill thickness. To control the models performance, calculating indices such as root mean square error （RMSE）, variance account for （VAF） and determination coefficient （R^2） were used. The MFS results show the significant prediction accuracy along with high performance compared to MVRA results. Finally, the sensitivity analysis of MFS results shows that the most and the least effective parameters on deformation modulus are weatherin~ and overburden height, respectively.
文摘The ability to speak two languages in the non-English-speaking countries is a remarkable achievement. There is a good reason to believe that bilingualism is the norm for the majority of people in the world, because 70% of the earth＇s population are supposed to be bilingual or multilingual. Our purpose of the study was to determine the participants＇ awareness of using true and false cognate words of L 1 （the first language） ＆ L2 （the second language） in learning English. Three hundred and eighty-five selected people from 3,789 statistical population participated in 2014--2015 at three levels of A.D., B.A., and M.A. of Islamic Azad University as well as teachers of English in English educational institutions in Zanjan （Iran）. Each educational level was considered as one category with the total sample calculated by using Kokran Formula, and the amount of each category was determined by using appropriate proportion and randomized categorical sampling method. The participants＇ age was between from 18 to 52, with a mean age of 29 years. The materials were 45 words of true and false cognate＇s words from 500 words by doing CVR （content validity ratio） and CVI （content validity index） （Lawshe＇s table with the index of 88% and 82% respectively） for being reliable and valid. ANOVA （Analysis of variance） was used for studying the effect of educational level on the rate of awareness. In other words, the awareness level has been compared in different educational levels. The results of Dankan test show that： There is no significant difference between the awareness of A.D., B.A., and M.A. levels, but there is a significant difference between the level of awareness of teachers group and the other groups （in true cognate words） and for false cognate words, there is no significant difference between the level of awareness of the four groups in this regard.
基金the National Natural Science Foundation of China for Distinguished Young Scholars，the National Key Basic Research Program of China (973 program)，the National Natural Science Foundation of China，the National Science and Technology Major Project，the Special Research Fund of State Key Laboratory，the 111 Project
文摘Orthogonal Frequency Division Multiplexing(OFDM) is an effective technique to deal with a frequency selective channel since it can convert the channel into some flat fading subchannels.However,very different output SNR values of the subchannels will lead to poor bit error performance when a linear equalizer and Equal Bit Allocation(EBA) are adopted in OFDM systems.So,we proposed three novel nonlinear Joint Transceiver(JT) schemes based on Zero-Forcing(ZF) criterion and Minimum Mean Square Error(MMSE) criterion respectively,which can transform all subchannels of an OFDM system into subchannels with identical channel gain.Thus,EBA is equivalent to the Optimum Bit Allocation(OBA) for these subchannels.Numerical analysis helps us to obtain the theoretical approximate BER values of the JT scheme.Simulation results verify the numerical analysis and confirm that the performance of our proposed JT scheme greatly outperforms the traditional linear equalizer with EBA at moderate and high SNR values.
基金funded by the Major State Basic Research Development Program of China (Grant No. 2013CBA01804)the National Natural Science Foundation of China (Grant Nos. 41121001, 40801027)the State Key Laboratory of Cryospheric Sciences (Grant No. SKLCS-ZZ- 2012-01-07)
文摘The accuracy of daily mean 2 meter air temperatures from five reanalyses are assessed against in-situ observations from Automatic Weather Stations in East Antarctica for 2005 to 2008. The five reanalyses all explain more than 70% of the average variance, and have annual root mean square errors （RMSE） between 3.4 and 6.9℃. The NOAA reanalyses, NCEP-1, NCEP-2 and 20CRv2, have cool biases of 2.5, 1.4 and 1.5℃, respectively. The ERA Interim and JCDAS reanalyses have warm biases of 1.7 and 2.0℃. All reanalyses generally perform better in the austral spring and worse in winter and autumn. They also show the best performance at an inland plateau site at 2800 m elevation, but are worst at Dome A, the summit of the East Antarctic ice sheet. In general, ERA Interim is superior to the other reanalyses, probably because of its 4D assimilation scheme. The three NOAA reanalyses perform worst; Their assimilation scheme is more constrained by limited observations and 20CRy2 has less input data, assimilating only surface pressure observations. Despite deficiencies and limitations, the reanalyses are still powerful tools for climate studies in the Antarctic region. However, more in-situ observations are required, especially from the vast interior of Antarctica.
文摘This paper presents an innovative and low-cost approach for nondestructive fruit quality analysis. The specialized optical fiber sensor developed and presented in this paper used a monochromatic wavelength, rather than a broad spectrum, to measure the intact carambola （star fruit） intrinsic quality, namely pH and firmness. The main objective of this research was to investigate the two optical fiber sensors used in this work, namely, the optical fiber red system （OF-RS） that operated with the peak sensitivity at 635 nm and the optical fiber near the infrared spectroscopy system （OF-NIRS） that operated with the peak sensitivity at 880nm. Both systems showed good accuracy in the pH and firmness measurement of the intact carambola with the correlation coefficient R over 0.75, and the measurement results were comparable with those of the commercial spectrometer. The best measurement results were obtained using OF-RS （pH： R = 0.876; the root mean square error （RMSE） = 0.211 pH; firmness： R = 0.872; RMSE = 0.909 kgf）.
文摘An improved method is proposed to simulate the scintillation introduced by the turbulence, based on the finite Markov state model. As a contrast to the literatures, uniformly distributed variables take place during a certain state, which contributes to equivalent simulation of the intensity fluctuations with fewer states than the traditional Markov model. It's also discovered that the proposed Markov model with 20 states provides a satisfactory approximation to the experimental results in the auto-covariance analysis. Moreover, the outage probability and mean fading time are more accurate than those of the traditional Markov model with equivalent states.
基金support through Grant-in-Aid for Scientific Research on Priority Areas (No. 18079010)from MEXT, Japan
文摘This paper analyzes performance of optimal channel estimation and multiuser detection(MUD) in a block-fading code-division multiple-access (CDMA) channel on the assumptions of randomspreading and large-system limit,by using the replica method developed in statistical mechanics.The authors find that the asymptotic spectral efficiency of the linear minimum mean-squared error(LMMSE) MUD which was proposed and analyzed by Evans and Tse in 2000 is indistinguishable fromthat of the optimal MUD for small system loads.Our results imply that performance of MUD scarcelyimproves even if one spends more computational cost than that of the LMMSE MUD,i.e.,at most thecube of the number of users,on the above-described conditions.
