The aim of this work was to evaluate and compare the performance of comparatively new synthetic PTW 60019 microDiamond with PTW 60017 Diode E detector in measuring the output factors (OF) of IntraOperative Radiation T...The aim of this work was to evaluate and compare the performance of comparatively new synthetic PTW 60019 microDiamond with PTW 60017 Diode E detector in measuring the output factors (OF) of IntraOperative Radiation Therapy (IORT) electron beams. For a given electron beam, OFs are defined as the ratio of the dose for any applicator size at the depth of maximum to that for a reference applicator. IORT is an innovative treatment technique that delivers a large single fraction of radiation dose to the tumor bed during surgery. The electron beams considered in this study were generated by the mobile NOVAC7 system. This device produces high-dose-per-pulse electron beams with four different energies in the range from 3 MeV to 9 MeV. We performed measurements for two higher energies, namely 7MeV and 9 MeV. The beam collimation was performed through Perspex (PMMA) cylindrical applicators with different diameters. The accurate dose delivery of IORT tightly depends on the precision of measured dose by reference applicator and the output factors of clinical applicators. The output factors were measured using microDiamond and Diode E detectors. The microDiamond detector performance was compared with a Diode E detector. Determined output factors of two detectors were in good agreement. The maximum deviations of output factors for microDiamond were found 2.74%, and 2.17% for 7 MeV and 9 MeV, respectively with respect to the PTW Diode E. The microDiamond detector was shown to exhibit excellent properties for output factor measurements and could be considered as a suitable tool for electron beam dosimetry.展开更多
Small radiation fields are abundantly used in modern radiotherapy techniques like in IMRT and SRS. In order to commission these techniques, dosimetric data for small fields is required. The purpose of this study is to...Small radiation fields are abundantly used in modern radiotherapy techniques like in IMRT and SRS. In order to commission these techniques, dosimetric data for small fields is required. The purpose of this study is to compare dosimetric measurements with two different ion chambers cc13, and cc01 for smaller fields. Dosimetric measurements are beam profile, output factor, pdds, and collimator factor. Dosimetric data is acquired in water phantom for two different photon beam energies 6 MV and 15 MV with zero gantry angle. In beam profiles cc13 chamber, measure wider penumbra as compare to cc01. And this wider measurement of penumbra occurs for smaller as well as for larger field sizes. Accumulated relative error in the measurement of penumbra for number of field sizes and 6 MV at dmax, and at 10 cm depth are 34.32% and 27.72% respectively. Accumulated relative error in the measurement of penumbra for number of field sizes and 15 MV at dmax, and at 10 cm depth are 28.49% and 23.92%. In case of output factor for smaller fields cc13 underestimates the output factor relative to cc01, with non-linear increase for smaller fields. But for larger fields, this increase in output factor is almost linear difference of two chambers is decreased. For very smaller fields × 2 cm, relative error in output factor of cc13 and cc01 is greater than 5% and rapidly increases with decreasing field size. But for lager fields, this relative error is negligible. In measurement of pdds after the buildup region difference occurs in the response of two chambers cc13 and cc01 for smaller fields. For field sizes ≤2 cm × 2 cm average cc13-cc01 at various depths 30 cm, 40 cm, 50 cm, 60 cm, 70 cm, and 80 cm is almost greater than 0.5 cm. And similarly as output factor, this difference (cc13-cc01) increases with field size decreasing.展开更多
In intensity modulated radiation treatment (IMRT) planning, the use of asymmetrically collimated fields that are placed on central axis or its off-set is mostly required. Output is the main topic discussed today for e...In intensity modulated radiation treatment (IMRT) planning, the use of asymmetrically collimated fields that are placed on central axis or its off-set is mostly required. Output is the main topic discussed today for extremely small and/or severe irregularly shaped fields. The air scatter data are involved directly or indirectly in obtaining the output. Despite the fact that extensive data have been published in many studies to provide a guide on the magnitude of output factor for clinical accelerators, there are very few data reviewed about output factor in-air or phantom for off-set fields. This study was aimed to investigate the impact of these conditions for small fields. This study was conducted in Elekta Synergy linear accelerator which produces 6 MV X-ray energy. The in-air output factor (Sc) has been measured by CC04 ion chamber with brass-alloy “build-up” cap and Dose-1 electrometer, and the total output (Scp) measurements were carried on at dose maximum depth in phantom by the same chamber and Thermoluminescence dosimeter (TLD) for 1 - 10 cm2 fields. The all measurements at center of isocenter and off-set fields at three directions (X2, Y1, Diagonal) were done. By decreasing field size from 10 to 2 cm2 at isocenter, the Sc value using CC04 was decreased to 5.4% and Scp using CC04 and TLD to 14.5% and 11% respectively. By increasing off-set value, the Sc and Scp values were increased in all directions comparing to central fields. The maximum increase was obtained in Y1 direction for Sc and Scp. TLD results for Scp is slightly higher than CC04. The dosimetric properties of small fields and their off-set should be evaluated and modelled appropriately in the treatment planning system to ensure accurate dose calculation in Intensity Modulated Radiation Treatment.展开更多
This paper estimates a stochastic frontier function using a panel data set that includes 4 961 farmer households for the period of 2005-2009 to decompose the growth of grain production and the total factor productivi...This paper estimates a stochastic frontier function using a panel data set that includes 4 961 farmer households for the period of 2005-2009 to decompose the growth of grain production and the total factor productivity （TFP） growth at the farmer level. The empirical results show that the major contributor to the grain output growth for farmers is input growth and that its average contribution accounts for 60.92% of farmer’s grain production growth in the period of 2006-2009, whereas the average contributions sourced from TFP growth and residuals are only 17.30 and 21.78%, respectively. The growth of intermediate inputs is a top contributor with an average contribution of 44.46%, followed by the planted area （18.16%）, investment in fixed assets （1.05%）, and labor input （-2.75%）, indicating that the contribution from the farmer’s input growth is mainly due to the growth of intermediate inputs and that the decline in labor inputs has become an obstacle for farmers in seeking grain output growth. Among the elements consisting of TFP growth, the contribution of technical progress is the largest （32.04%）, followed by grain subsidies （8.55%）, the average monthly temperature （4.26%）, the average monthly precipitation （-0.88%）, the adjusted scale effect （-5.66%）, and growth in technical efficiency （-21.01%）. In general, the contribution of climate factors and agricultural policy factor are positive and significant.展开更多
[Objective] The aim was to explore interrelationship between agricultural input and output in Jiangsu and the influence degrees of input factors on agricultur-al output. [Method] Quantitative analysis and evaluation w...[Objective] The aim was to explore interrelationship between agricultural input and output in Jiangsu and the influence degrees of input factors on agricultur-al output. [Method] Quantitative analysis and evaluation were made on agricultural input and output in Jiangsu during 1990-2012 as per factor analysis and regression analysis. [Result] The result of factor analysis showed that since the 1990s, the comprehensive efficiency of agricultural input/output in Jiangsu was growing and in-put/output of agriculture, forestry, animal husbandry and fishery, crop farming, and of food production were extracted, whose scores reflect the changes of input/output ef-ficiencies in terms of agriculture, forestry, animal husbandry, fishery, crop farming and food production in the two decades. The results of regression analysis indicated that the effects of the three indices on agricultural output tended to be volatile and the influence degrees were concluded also by regression parameters. [Conclusion] The research provides theoretical references for agricultural input/output structure in Jiangsu Province.展开更多
Based on the theory of system energy-saving, a multilevel input-output computational model ot the iron and steel enterprise was established. And one example was calculated using this model to analyze the product energ...Based on the theory of system energy-saving, a multilevel input-output computational model ot the iron and steel enterprise was established. And one example was calculated using this model to analyze the product energy value, the process of energy consumption and energy consumption per ton of steel of an iron and steel enterprise. The influences of factory layout, steel ratio and production structure are calculated and analyzed. The calculation example indicates that reasonable factory layout is helpful to reduce its transportation energy consumption, decrease loss of heat, improve product rate and reduce environmental contamination; ore to steel ratio and iron to steel ratio decrease at the same degree; the influence of ore to steel ratio on energy intensity per ton is less than that of iron to steel ratio. The lord process product structure has a certain effect on comprehensive energy consumption per ton of steel.展开更多
Analysis of carbon emission mechanism based on regional perspectives is an im- portant research method capable of achieving energy savings and emission reductions. Xin- jiang, an important Chinese energy production ba...Analysis of carbon emission mechanism based on regional perspectives is an im- portant research method capable of achieving energy savings and emission reductions. Xin- jiang, an important Chinese energy production base, is currently going through a period of strategic opportunities for rapid development. Ensuring stable socio-economic development while achieving energy savings and meeting emission reductions targets, is the key issue currently facing the region. This paper is based on the input-output theory, and conducts a structural decomposition analysis on the factors affecting energy-related carbon emissions in Xinjiang from 1997 to 2007; this analysis employs a hybrid input-output analysis framework of ＂energy - economy - carbon emissions＂. （1） Xinjiang＇s carbon emissions from energy con- sumption increased from 20.70 million tons in 1997 to 40.34 million tons in 2007; carbon emissions growth was mainly concentrated in the production and processing of energy re- sources, the mining of mineral resources, and the processing industry. （2） The analysis of the direct effects of the influencing factors on carbon emissions showed that the change in per capita GDP, the final demand structure, the population scale, and the production structure were the important factors causing an increase in carbon emissions, while the decrease in carbon emission intensity during this period was the important influencing factor in stopping the growth of carbon emissions. This showed that while the sizes of Xinjiang＇s economy and population were growing, the economic structure had not been effectively optimized and the production technology had not been efficiently improved, resulting in a rapid growth of carbon emissions from energy consumption. （3） The analysis of the indirect effects of the influencing factors of carbon emission showed that the inter-provincial export, fixed capital formation, and the consumption by urban residents had significant influence on the changes in carbon emissions from energy consumption in Xinjiang. （4） The growth of investments in fixed assets of carbon intensive industry sectors, in addition to the growth of inter-provincial exports ofenergy resource products, makes the transfer effect of inter-provincial ＂embodied carbon＂ very significant.展开更多
To deal with colored noise and unexpected load disturbance in identification of industrial processes with time delay, a bias-eliminated iterative least-squares(ILS) identification method is proposed in this paper to e...To deal with colored noise and unexpected load disturbance in identification of industrial processes with time delay, a bias-eliminated iterative least-squares(ILS) identification method is proposed in this paper to estimate the output error model parameters and time delay simultaneously. An extended observation vector is constructed to establish an ILS identification algorithm. Moreover, a variable forgetting factor is introduced to enhance the convergence rate of parameter estimation. For consistent estimation, an instrumental variable method is given to deal with the colored noise. The convergence and upper bound error of parameter estimation are analyzed. Two illustrative examples are used to show the effectiveness and merits of the proposed method.展开更多
The agricultural sector is the basis of livelihood for a large proportion of society in Ethiopia. In the three political regimes in modern Ethiopia, the Imperial, the military and the Ethiopian people revolutionary de...The agricultural sector is the basis of livelihood for a large proportion of society in Ethiopia. In the three political regimes in modern Ethiopia, the Imperial, the military and the Ethiopian people revolutionary democratic front (EPRDF), agriculture has been regarded as a critical sector. The Agricultural Development Led Industrialization (ADLI) is the national policy of the country. Regardless of the government policy attention and investment, there is a long way to go for smallholders to ensure food self-sufficiency. Agriculture is the base of our food, transformation to industrialization, climatic change control system. Agriculture is the soul of our sovereignty for development as well as poverty reduction for individuals and country level. In Ethiopia, population density is high and has been increasing and agricultural land has been decreasing because of fragmenting or converting it into residential plots. To meet the domestic food requirements, use of improved production technologies developed by research is come out to be important. Therefore, the goal of this study was to analyze factors that affect the performance of agricultural products in Amahara region national state and to determine the highly significant input factors for producing high and qualified agricultural outputs. Data regarding total agricultural outputs and its input factors in study area of Amahara region from 2010 to 2018 was obtained from Amhara national state branch of the Ethiopian institute of agricultural sector. Correlation analyses were used to examine the strength of the relationship between each of the determinant factors with total agricultural output, while multiple regression analysis was employed to examine the simultaneous effects of several independent variables on the dependent variable, total agricultural outputs. These analyses were employed through the packages R and Stata to achieve the main objectives of the study. All of the independent variables were highly correlated with the total agricultural output. The overall regression model was highly significant (p-value < 0.01) with F = 45.532. The R-squared value implies that 93.8% percent of the changes in average total agricultural outputs are successfully explained by the variables used in the model of this study. If we take model size into account, 91.8% percent of the variation in average total agricultural output was explained by the values of the independent variables. Specifically, among the independent variables irrigated land, fertilizer, improved seed and pesticides are the most significant factors for total products (p-value < 0.05).展开更多
This paper analyzes the citrus input-output efficiency by using the DEA-Malmquist productivity index methods based on the data of six counties in Jiangxi Province from 2010 to 2013.The result shows that TFP of Jiangxi...This paper analyzes the citrus input-output efficiency by using the DEA-Malmquist productivity index methods based on the data of six counties in Jiangxi Province from 2010 to 2013.The result shows that TFP of Jiangxi citrus is at low level overall,but the development is rapid.Technological progress is the driving force to promote productivity growth.Based on the static analysis study of six counties in 2013,it is found that the available input factors on the whole are in an ideal condition,and the citrus input factors in a few counties are redundant.Therefore,according to the results,the following policy recommendations are proposed:speeding up the intensive production of citrus in Jiangxi Province,to maximize the scale effect;adjusting the input ratio of various factors of production,so as to improve the citrus input-output efficiency.展开更多
By adding a suitable LC filter to the input of a Buck converter, a high-power-factor buck converter is proposed. The converter can operate in the discontinuous-output-current mode operation. A Buck converter in this o...By adding a suitable LC filter to the input of a Buck converter, a high-power-factor buck converter is proposed. The converter can operate in the discontinuous-output-current mode operation. A Buck converter in this operation mode features simple control as the constant duty cycle PWM used. The operation condition of the converter is studied. The validity of analysis is verified by Simulation and Experimental results.展开更多
文摘The aim of this work was to evaluate and compare the performance of comparatively new synthetic PTW 60019 microDiamond with PTW 60017 Diode E detector in measuring the output factors (OF) of IntraOperative Radiation Therapy (IORT) electron beams. For a given electron beam, OFs are defined as the ratio of the dose for any applicator size at the depth of maximum to that for a reference applicator. IORT is an innovative treatment technique that delivers a large single fraction of radiation dose to the tumor bed during surgery. The electron beams considered in this study were generated by the mobile NOVAC7 system. This device produces high-dose-per-pulse electron beams with four different energies in the range from 3 MeV to 9 MeV. We performed measurements for two higher energies, namely 7MeV and 9 MeV. The beam collimation was performed through Perspex (PMMA) cylindrical applicators with different diameters. The accurate dose delivery of IORT tightly depends on the precision of measured dose by reference applicator and the output factors of clinical applicators. The output factors were measured using microDiamond and Diode E detectors. The microDiamond detector performance was compared with a Diode E detector. Determined output factors of two detectors were in good agreement. The maximum deviations of output factors for microDiamond were found 2.74%, and 2.17% for 7 MeV and 9 MeV, respectively with respect to the PTW Diode E. The microDiamond detector was shown to exhibit excellent properties for output factor measurements and could be considered as a suitable tool for electron beam dosimetry.
文摘Small radiation fields are abundantly used in modern radiotherapy techniques like in IMRT and SRS. In order to commission these techniques, dosimetric data for small fields is required. The purpose of this study is to compare dosimetric measurements with two different ion chambers cc13, and cc01 for smaller fields. Dosimetric measurements are beam profile, output factor, pdds, and collimator factor. Dosimetric data is acquired in water phantom for two different photon beam energies 6 MV and 15 MV with zero gantry angle. In beam profiles cc13 chamber, measure wider penumbra as compare to cc01. And this wider measurement of penumbra occurs for smaller as well as for larger field sizes. Accumulated relative error in the measurement of penumbra for number of field sizes and 6 MV at dmax, and at 10 cm depth are 34.32% and 27.72% respectively. Accumulated relative error in the measurement of penumbra for number of field sizes and 15 MV at dmax, and at 10 cm depth are 28.49% and 23.92%. In case of output factor for smaller fields cc13 underestimates the output factor relative to cc01, with non-linear increase for smaller fields. But for larger fields, this increase in output factor is almost linear difference of two chambers is decreased. For very smaller fields × 2 cm, relative error in output factor of cc13 and cc01 is greater than 5% and rapidly increases with decreasing field size. But for lager fields, this relative error is negligible. In measurement of pdds after the buildup region difference occurs in the response of two chambers cc13 and cc01 for smaller fields. For field sizes ≤2 cm × 2 cm average cc13-cc01 at various depths 30 cm, 40 cm, 50 cm, 60 cm, 70 cm, and 80 cm is almost greater than 0.5 cm. And similarly as output factor, this difference (cc13-cc01) increases with field size decreasing.
文摘In intensity modulated radiation treatment (IMRT) planning, the use of asymmetrically collimated fields that are placed on central axis or its off-set is mostly required. Output is the main topic discussed today for extremely small and/or severe irregularly shaped fields. The air scatter data are involved directly or indirectly in obtaining the output. Despite the fact that extensive data have been published in many studies to provide a guide on the magnitude of output factor for clinical accelerators, there are very few data reviewed about output factor in-air or phantom for off-set fields. This study was aimed to investigate the impact of these conditions for small fields. This study was conducted in Elekta Synergy linear accelerator which produces 6 MV X-ray energy. The in-air output factor (Sc) has been measured by CC04 ion chamber with brass-alloy “build-up” cap and Dose-1 electrometer, and the total output (Scp) measurements were carried on at dose maximum depth in phantom by the same chamber and Thermoluminescence dosimeter (TLD) for 1 - 10 cm2 fields. The all measurements at center of isocenter and off-set fields at three directions (X2, Y1, Diagonal) were done. By decreasing field size from 10 to 2 cm2 at isocenter, the Sc value using CC04 was decreased to 5.4% and Scp using CC04 and TLD to 14.5% and 11% respectively. By increasing off-set value, the Sc and Scp values were increased in all directions comparing to central fields. The maximum increase was obtained in Y1 direction for Sc and Scp. TLD results for Scp is slightly higher than CC04. The dosimetric properties of small fields and their off-set should be evaluated and modelled appropriately in the treatment planning system to ensure accurate dose calculation in Intensity Modulated Radiation Treatment.
基金supported by Japan International Research Center for Agricultural Sciences
文摘This paper estimates a stochastic frontier function using a panel data set that includes 4 961 farmer households for the period of 2005-2009 to decompose the growth of grain production and the total factor productivity （TFP） growth at the farmer level. The empirical results show that the major contributor to the grain output growth for farmers is input growth and that its average contribution accounts for 60.92% of farmer’s grain production growth in the period of 2006-2009, whereas the average contributions sourced from TFP growth and residuals are only 17.30 and 21.78%, respectively. The growth of intermediate inputs is a top contributor with an average contribution of 44.46%, followed by the planted area （18.16%）, investment in fixed assets （1.05%）, and labor input （-2.75%）, indicating that the contribution from the farmer’s input growth is mainly due to the growth of intermediate inputs and that the decline in labor inputs has become an obstacle for farmers in seeking grain output growth. Among the elements consisting of TFP growth, the contribution of technical progress is the largest （32.04%）, followed by grain subsidies （8.55%）, the average monthly temperature （4.26%）, the average monthly precipitation （-0.88%）, the adjusted scale effect （-5.66%）, and growth in technical efficiency （-21.01%）. In general, the contribution of climate factors and agricultural policy factor are positive and significant.
文摘[Objective] The aim was to explore interrelationship between agricultural input and output in Jiangsu and the influence degrees of input factors on agricultur-al output. [Method] Quantitative analysis and evaluation were made on agricultural input and output in Jiangsu during 1990-2012 as per factor analysis and regression analysis. [Result] The result of factor analysis showed that since the 1990s, the comprehensive efficiency of agricultural input/output in Jiangsu was growing and in-put/output of agriculture, forestry, animal husbandry and fishery, crop farming, and of food production were extracted, whose scores reflect the changes of input/output ef-ficiencies in terms of agriculture, forestry, animal husbandry, fishery, crop farming and food production in the two decades. The results of regression analysis indicated that the effects of the three indices on agricultural output tended to be volatile and the influence degrees were concluded also by regression parameters. [Conclusion] The research provides theoretical references for agricultural input/output structure in Jiangsu Province.
基金Item Sponsored by National Science and Technology Support Plan(863)of China(2008AA042901)
文摘Based on the theory of system energy-saving, a multilevel input-output computational model ot the iron and steel enterprise was established. And one example was calculated using this model to analyze the product energy value, the process of energy consumption and energy consumption per ton of steel of an iron and steel enterprise. The influences of factory layout, steel ratio and production structure are calculated and analyzed. The calculation example indicates that reasonable factory layout is helpful to reduce its transportation energy consumption, decrease loss of heat, improve product rate and reduce environmental contamination; ore to steel ratio and iron to steel ratio decrease at the same degree; the influence of ore to steel ratio on energy intensity per ton is less than that of iron to steel ratio. The lord process product structure has a certain effect on comprehensive energy consumption per ton of steel.
基金National Natural Science Foundation of China, No.41501144 National Key Research and Development Program, No.2016YFA0602801+2 种基金 Guangdong Academy of Sciences Youth Science Foundation, No.qn.ij201501 High-level Leading Talent Introduction Program of GDAS, No.2016GDASRC-0101 Scientific Platform and Innovation Capability Construction Program of GDAS, No.2016GDASPT-0210.
文摘Analysis of carbon emission mechanism based on regional perspectives is an im- portant research method capable of achieving energy savings and emission reductions. Xin- jiang, an important Chinese energy production base, is currently going through a period of strategic opportunities for rapid development. Ensuring stable socio-economic development while achieving energy savings and meeting emission reductions targets, is the key issue currently facing the region. This paper is based on the input-output theory, and conducts a structural decomposition analysis on the factors affecting energy-related carbon emissions in Xinjiang from 1997 to 2007; this analysis employs a hybrid input-output analysis framework of ＂energy - economy - carbon emissions＂. （1） Xinjiang＇s carbon emissions from energy con- sumption increased from 20.70 million tons in 1997 to 40.34 million tons in 2007; carbon emissions growth was mainly concentrated in the production and processing of energy re- sources, the mining of mineral resources, and the processing industry. （2） The analysis of the direct effects of the influencing factors on carbon emissions showed that the change in per capita GDP, the final demand structure, the population scale, and the production structure were the important factors causing an increase in carbon emissions, while the decrease in carbon emission intensity during this period was the important influencing factor in stopping the growth of carbon emissions. This showed that while the sizes of Xinjiang＇s economy and population were growing, the economic structure had not been effectively optimized and the production technology had not been efficiently improved, resulting in a rapid growth of carbon emissions from energy consumption. （3） The analysis of the indirect effects of the influencing factors of carbon emission showed that the inter-provincial export, fixed capital formation, and the consumption by urban residents had significant influence on the changes in carbon emissions from energy consumption in Xinjiang. （4） The growth of investments in fixed assets of carbon intensive industry sectors, in addition to the growth of inter-provincial exports ofenergy resource products, makes the transfer effect of inter-provincial ＂embodied carbon＂ very significant.
基金Supported by the National Thousand Talents Program of Chinathe National Natural Science Foundation of China(61473054)the Fundamental Research Funds for the Central Universities of China
文摘To deal with colored noise and unexpected load disturbance in identification of industrial processes with time delay, a bias-eliminated iterative least-squares(ILS) identification method is proposed in this paper to estimate the output error model parameters and time delay simultaneously. An extended observation vector is constructed to establish an ILS identification algorithm. Moreover, a variable forgetting factor is introduced to enhance the convergence rate of parameter estimation. For consistent estimation, an instrumental variable method is given to deal with the colored noise. The convergence and upper bound error of parameter estimation are analyzed. Two illustrative examples are used to show the effectiveness and merits of the proposed method.
文摘The agricultural sector is the basis of livelihood for a large proportion of society in Ethiopia. In the three political regimes in modern Ethiopia, the Imperial, the military and the Ethiopian people revolutionary democratic front (EPRDF), agriculture has been regarded as a critical sector. The Agricultural Development Led Industrialization (ADLI) is the national policy of the country. Regardless of the government policy attention and investment, there is a long way to go for smallholders to ensure food self-sufficiency. Agriculture is the base of our food, transformation to industrialization, climatic change control system. Agriculture is the soul of our sovereignty for development as well as poverty reduction for individuals and country level. In Ethiopia, population density is high and has been increasing and agricultural land has been decreasing because of fragmenting or converting it into residential plots. To meet the domestic food requirements, use of improved production technologies developed by research is come out to be important. Therefore, the goal of this study was to analyze factors that affect the performance of agricultural products in Amahara region national state and to determine the highly significant input factors for producing high and qualified agricultural outputs. Data regarding total agricultural outputs and its input factors in study area of Amahara region from 2010 to 2018 was obtained from Amhara national state branch of the Ethiopian institute of agricultural sector. Correlation analyses were used to examine the strength of the relationship between each of the determinant factors with total agricultural output, while multiple regression analysis was employed to examine the simultaneous effects of several independent variables on the dependent variable, total agricultural outputs. These analyses were employed through the packages R and Stata to achieve the main objectives of the study. All of the independent variables were highly correlated with the total agricultural output. The overall regression model was highly significant (p-value < 0.01) with F = 45.532. The R-squared value implies that 93.8% percent of the changes in average total agricultural outputs are successfully explained by the variables used in the model of this study. If we take model size into account, 91.8% percent of the variation in average total agricultural output was explained by the values of the independent variables. Specifically, among the independent variables irrigated land, fertilizer, improved seed and pesticides are the most significant factors for total products (p-value < 0.05).
文摘This paper analyzes the citrus input-output efficiency by using the DEA-Malmquist productivity index methods based on the data of six counties in Jiangxi Province from 2010 to 2013.The result shows that TFP of Jiangxi citrus is at low level overall,but the development is rapid.Technological progress is the driving force to promote productivity growth.Based on the static analysis study of six counties in 2013,it is found that the available input factors on the whole are in an ideal condition,and the citrus input factors in a few counties are redundant.Therefore,according to the results,the following policy recommendations are proposed:speeding up the intensive production of citrus in Jiangxi Province,to maximize the scale effect;adjusting the input ratio of various factors of production,so as to improve the citrus input-output efficiency.
文摘By adding a suitable LC filter to the input of a Buck converter, a high-power-factor buck converter is proposed. The converter can operate in the discontinuous-output-current mode operation. A Buck converter in this operation mode features simple control as the constant duty cycle PWM used. The operation condition of the converter is studied. The validity of analysis is verified by Simulation and Experimental results.
