Sense of economic gain of e-commerce participation is an important aspect for evaluating the inclusiveness of e-commerce development.Based on the data of 6,242 rural households collected from the 2017 summer surveys c...Sense of economic gain of e-commerce participation is an important aspect for evaluating the inclusiveness of e-commerce development.Based on the data of 6,242 rural households collected from the 2017 summer surveys conducted by the China Institute for Rural Studies(CIRS),Tsinghua University,this paper evaluates the effects of e-commerce participation on rural households’sense of economic gain with the propensity score matching(PSM)method,and carries out grouped comparisons between poor and non-poor households.Speci fically,the“Self-evaluated income level relative to fellow villagers”measures respondents’sense of economic gain in the relative sense,and“Percentage of expected household income growth(reduction)in 2018 over 2017”measures future income growth expectation.Findings suggest that e-commerce participation signi ficantly increased sample households’sense of economic gain relative to their fellow villagers and their future income growth expectation.Yet grouped comparisons offer different conclusions:E-commerce participation increased poor households’sense of economic gain compared with fellow villagers more than it did for non-poor households.E-commerce participation did little to increase poor households’future income growth expectation.Like many other poverty reduction programs,pro-poor e-commerce helps poor households with policy preferences but have yet to help them foster skills to prosper in the long run.The sustainability and quality of perceived relative economic gain for poor households are yet to be further observed and examined.All poverty reduction initiatives including pro-poor e-commerce must help poor households develop endogenous growth momentum to prosper beyond the effects of short-term pro-poor policies.展开更多
The accuracy of the measured current is a preeminent parameter for Current Control based Power Converter applications to ensure genuine operation of the designed converter.The current measurement accuracy can be affec...The accuracy of the measured current is a preeminent parameter for Current Control based Power Converter applications to ensure genuine operation of the designed converter.The current measurement accuracy can be affected by several parameters which includes the type of technology used,components used for the selected technology,aging,usage,operating and environmental conditions.The effect of gain resistors and their manufacturing tolerances on differential amplifier-based buck converter current measurement is investigated in this work.The analysis mainly focused on the output voltage variation and its accuracy with respect to the change in gain resistance tolerances.The gain resistors with 5%,1%,0.5%and 0.1%manufacturing tolerances taken for the worst-case analysis and the calculated performance results are compared and verified with the simula-tion results.The Operational amplifiers(Op-Amp)for high frequency power con-verter applications must operate in a high frequency noise environment and the intended current measuring system must manage common mode noise distur-bances paired with the signal to be measured.Based on the Common Mode Rejec-tion Ratio(CMRR)the common mode voltages and noise signals will effectively getfiltered out.Lesser CMRR results in lower common mode signal rejection,resulting in poor precision and noise rejection.In differential amplifiers,the CMRR predominantly depends on gain resistors.So,the variations in Common Mode Rejection Ratio due to gain resistor tolerances also analyzed and compared with the output voltage variations.Besides the effects of resistor tolerances,this paper also examines the effect of Op-Amp offset voltage on output accuracy spe-cifically for low magnitude input currents.The obtained results from this analysis clearly shows that the gain resistors with 0.1%tolerance gives maximum accuracy with improved CMRR and accuracy at low magnitude input currents will get well improved by using Op-Amps with Low Offset voltage specifications.展开更多
基金sponsored by the Youth Program of the National Social Sciences Fund of China (NSSFC)“Study on the Multidimensional Poverty of Rural Elderly Population and Targeted Poverty Reduction”(Grant No. 17CGL030)the Youth Research Start-Up Program of the Chinese Academy of Social Sciences (CASS)“Study on the Development Mechanism of Inclusive E-Commerce in the Countryside”Program of the National Natural Science Foundation of China (NSFC)“Research on the Mechanism and Effects of Precise Poverty Alleviation and Internet Poverty Alleviation in Rural China”(Grant No. 71661147001)。
文摘Sense of economic gain of e-commerce participation is an important aspect for evaluating the inclusiveness of e-commerce development.Based on the data of 6,242 rural households collected from the 2017 summer surveys conducted by the China Institute for Rural Studies(CIRS),Tsinghua University,this paper evaluates the effects of e-commerce participation on rural households’sense of economic gain with the propensity score matching(PSM)method,and carries out grouped comparisons between poor and non-poor households.Speci fically,the“Self-evaluated income level relative to fellow villagers”measures respondents’sense of economic gain in the relative sense,and“Percentage of expected household income growth(reduction)in 2018 over 2017”measures future income growth expectation.Findings suggest that e-commerce participation signi ficantly increased sample households’sense of economic gain relative to their fellow villagers and their future income growth expectation.Yet grouped comparisons offer different conclusions:E-commerce participation increased poor households’sense of economic gain compared with fellow villagers more than it did for non-poor households.E-commerce participation did little to increase poor households’future income growth expectation.Like many other poverty reduction programs,pro-poor e-commerce helps poor households with policy preferences but have yet to help them foster skills to prosper in the long run.The sustainability and quality of perceived relative economic gain for poor households are yet to be further observed and examined.All poverty reduction initiatives including pro-poor e-commerce must help poor households develop endogenous growth momentum to prosper beyond the effects of short-term pro-poor policies.
文摘The accuracy of the measured current is a preeminent parameter for Current Control based Power Converter applications to ensure genuine operation of the designed converter.The current measurement accuracy can be affected by several parameters which includes the type of technology used,components used for the selected technology,aging,usage,operating and environmental conditions.The effect of gain resistors and their manufacturing tolerances on differential amplifier-based buck converter current measurement is investigated in this work.The analysis mainly focused on the output voltage variation and its accuracy with respect to the change in gain resistance tolerances.The gain resistors with 5%,1%,0.5%and 0.1%manufacturing tolerances taken for the worst-case analysis and the calculated performance results are compared and verified with the simula-tion results.The Operational amplifiers(Op-Amp)for high frequency power con-verter applications must operate in a high frequency noise environment and the intended current measuring system must manage common mode noise distur-bances paired with the signal to be measured.Based on the Common Mode Rejec-tion Ratio(CMRR)the common mode voltages and noise signals will effectively getfiltered out.Lesser CMRR results in lower common mode signal rejection,resulting in poor precision and noise rejection.In differential amplifiers,the CMRR predominantly depends on gain resistors.So,the variations in Common Mode Rejection Ratio due to gain resistor tolerances also analyzed and compared with the output voltage variations.Besides the effects of resistor tolerances,this paper also examines the effect of Op-Amp offset voltage on output accuracy spe-cifically for low magnitude input currents.The obtained results from this analysis clearly shows that the gain resistors with 0.1%tolerance gives maximum accuracy with improved CMRR and accuracy at low magnitude input currents will get well improved by using Op-Amps with Low Offset voltage specifications.
