China implemented the public hospital reform in 2012. This study utilized bootstrapping data envelopment analysis(DEA) to evaluate the technical efficiency(TE) and productivity of county public hospitals in Easter...China implemented the public hospital reform in 2012. This study utilized bootstrapping data envelopment analysis(DEA) to evaluate the technical efficiency(TE) and productivity of county public hospitals in Eastern, Central, and Western China after the 2012 public hospital reform. Data from 127 county public hospitals(39, 45, and 43 in Eastern, Central, and Western China, respectively) were collected during 2012–2015. Changes of TE and productivity over time were estimated by bootstrapping DEA and bootstrapping Malmquist. The disparities in TE and productivity among public hospitals in the three regions of China were compared by Kruskal–Wallis H test and Mann–Whitney U test. The average bias-corrected TE values for the four-year period were 0.6442, 0.5785, 0.6099, and 0.6094 in Eastern, Central, and Western China, and the entire country respectively, with average non-technical efficiency, low pure technical efficiency(PTE), and high scale efficiency found. Productivity increased by 8.12%, 0.25%, 12.11%, and 11.58% in China and its three regions during 2012–2015, and such increase in productivity resulted from progressive technological changes by 16.42%, 6.32%, 21.08%, and 21.42%, respectively. The TE and PTE of the county hospitals significantly differed among the three regions of China. Eastern and Western China showed significantly higher TE and PTE than Central China. More than 60% of county public hospitals in China and its three areas operated at decreasing return scales. There was a considerable space for TE improvement in county hospitals in China and its three regions. During 2012–2015, the hospitals experienced progressive productivity; however, the PTE changed adversely. Moreover, Central China continuously achieved a significantly lower efficiency score than Eastern and Western China. Decision makers and administrators in China should identify the causes of the observed inefficiencies and take appropriate measures to increase the efficiency of county public hospitals in the three areas of China, especially in Central China.展开更多
Although mining production depends on various equipments, significant amount of production loss can be attributed a specific equipment or fleet. Bottleneck is defined not only by production loss but also by our satisf...Although mining production depends on various equipments, significant amount of production loss can be attributed a specific equipment or fleet. Bottleneck is defined not only by production loss but also by our satisfaction from the equipment. The user satisfaction could be measured as machine effectiveness.Mining literatures on performance improvement and optimization of equipment operations assert importance of availability, utilization and production performance as key parameters. These three parameters are useful for evaluating effectiveness of equipment. Mine production index(MPI), which can represent the effect of these factors, has been applied for continuous operation in mining. MPI uses Fuzzy Delphi Analytical Hierarchy Process to determine importance of each three parameter for individual equipment. A case study in a Swedish open pit mine was done to evaluate the field application of MPI.The results reveal that crusher is the bottleneck equipment in studied mine. As a methodical approach,an algorithm which uses MPI and detects bottleneck in continuous mining operation has been proposed.展开更多
Hydrothermal condition is mismatched in arid and semi-arid regions,particularly in Central Asia(including Kazakhstan,Kyrgyzstan,Tajikistan,Uzbekistan,and Turkmenistan),resulting many environmental limitations.In this ...Hydrothermal condition is mismatched in arid and semi-arid regions,particularly in Central Asia(including Kazakhstan,Kyrgyzstan,Tajikistan,Uzbekistan,and Turkmenistan),resulting many environmental limitations.In this study,we projected hydrothermal condition in Central Asia based on bias-corrected multi-model ensembles(MMEs)from the Coupled Model Intercomparison Project Phase 6(CMIP6)under four Shared Socioeconomic Pathway and Representative Concentration Pathway(SSP-RCP)scenarios(SSP126(SSP1-RCP2.6),SSP245(SSP2-RCP4.5),SSP460(SSP4-RCP6.0),and SSP585(SSP5-RCP8.5))during 2015-2100.The bias correction and spatial disaggregation,water-thermal product index,and sensitivity analysis were used in this study.The results showed that the hydrothermal condition is mismatched in the central and southern deserts,whereas the region of Pamir Mountains and Tianshan Mountains as well as the northern plains of Kazakhstan showed a matched hydrothermal condition.Compared with the historical period,the matched degree of hydrothermal condition improves during 2046-2075,but degenerates during 2015-2044 and 2076-2100.The change of hydrothermal condition is sensitive to precipitation in the northern regions and the maximum temperatures in the southern regions.The result suggests that the optimal scenario in Central Asia is SSP126 scenario,while SSP585 scenario brings further hydrothermal contradictions.This study provides scientific information for the development and sustainable utilization of hydrothermal resources in arid and semi-arid regions under climate change.展开更多
Climate warming is expected to influence forest growth,composition and distribution.However,accurately estimating and predicting forest biomass,potential productivity or forest growth is still a challenge for forest m...Climate warming is expected to influence forest growth,composition and distribution.However,accurately estimating and predicting forest biomass,potential productivity or forest growth is still a challenge for forest managers dealing with land-use at the stand to regional levels.In the present study,we predicted the potential productivity(PP)of forest under current and future climate scenarios(RCP2.6,RCP4.5,RCP6.0 and RCP8.5)in Jilin province,northeastern China by using Paterson’s Climate Vegetation and Productivity(CVP)index model.The PP was validated by comparing it with the mean and maximum net primary production calculated from light energy utilization(GLM_PEM).Our results indicated that using the CVP index model is partially valid for predicting the potential forest productivity in northeastern China.PP exhibited obvious spatial heterogeneity varying from 4.6 to 8.9 m3 ha-1 year-1 with an increasing tendency from northwest to southeast driven by the precipitation across the region.The number of vegetation-active months,precipitation and insolation coefficient were identified as the primary factors affecting PP,but no significant relationship was found for warmest temperature or temperature fluctuation.Under future climate scenarios,PP across the Jilin Province is expected to increase from 1.38%(RCP2.6 in 2050)to 15.30%(RCP8.5 in 2070),especially in the eastern Songnen Plain(SE)for the RCP8.5 scenarios.展开更多
During the last decade,the food and beverage industry has been one of the most significant and prioritized industries that contributed to the economic growth in Vietnam.Therefore,how to enhance the performance of food...During the last decade,the food and beverage industry has been one of the most significant and prioritized industries that contributed to the economic growth in Vietnam.Therefore,how to enhance the performance of food and beverage firms has become a critical factor for Vietnam’s economic development.This research aims to use the data envelopment analysis(DEA)and the Malmquist productivity index(MPI)to assess changes in operational performance and productivity of listed lead food and beverage firms in Vietnam during the period between 2015 and 2020.The obtained results reveal that Vietnamese food and beverage firms were generally inefficient between 2015 and 2020 because the number of relatively inefficient companies was higher than the relatively efficient ones in each year between 2015 and 2020.The MPI findings indicate the growth in productivity during the study period as a result of technological progress.By integrating the findings of the relative efficiency and productivity change,this study creates five decision-making matrixes for five periods,respectively,from 2015 to 2020 to position the food and beverage firms in each sector.The analytical results provide instructions to senior managers on developing strategy for increasing efficiency of food and beverage listed companies in Vietnam.展开更多
The calculation of the overall profit Malmquist productivity index(MPI)requires precise and accurate information on the input,output,input-output prices of each decision making unit(DMU).However,in many situations,som...The calculation of the overall profit Malmquist productivity index(MPI)requires precise and accurate information on the input,output,input-output prices of each decision making unit(DMU).However,in many situations,some inputs and/or outputs and input-output prices are imprecise.As such,we consider the overall profit MPI problem when the input,output,and input-output prices are imprecise and vary over intervals,showing that method(MCM 54:2827–2838,2011)has some shortfalls.To remedy these shortfalls,we propose another method for measuring the overall profit MPI when the inputs,outputs,and price vectors vary over intervals.That is,to calculate the overall profit efficiency intervals,cone-ratio data envelopment analysis models can be applied to the incorporated information as weight restrictions.Further,we provide a new approach to calculating the upper bound of the overall profit efficiency of each DMU.A numerical example is provided for illustrating the proposed method.展开更多
Agricultural product price index insurance is a kind of index insurance. It avoids defects of traditional agricultural insurance,such as moral hazards,adverse selection,and high management cost. On the basis of studyi...Agricultural product price index insurance is a kind of index insurance. It avoids defects of traditional agricultural insurance,such as moral hazards,adverse selection,and high management cost. On the basis of studying agricultural product price index insurance of all areas of China,this paper analyzed characteristics of agricultural product price index insurance from object selection,product object,premium design,and policy support,and discussed feasibility of extending agricultural product price index insurance in an all-round way.展开更多
In Asia, the rice crop sustains millions of people. However, growing demand for this crop needs to be met while simultaneously reducing its water consumption to cope with the effects of climate change. Lowland croppin...In Asia, the rice crop sustains millions of people. However, growing demand for this crop needs to be met while simultaneously reducing its water consumption to cope with the effects of climate change. Lowland cropping systems are the most common and productive but have particularly high water requirements. High-yielding rice genotypes adapted to drier environments(such as rainfed or aerobic rice ecosystems) are needed to increase the water use efficiency of cropping. Identifying these genotypes requires fast and more accurate selection methods. It is hypothesized that applying a new quantitative selection method(the score index selection method), can usefully compare rice yield responses over different years and stress intensities to select genotypes more rapidly and efficiently. Applying the score index to previously published rice yield data for 39 genotypes grown in no-stress and two stress environments, identified three genotypes(ARB 8, IR55419-04 and ARB 7) with higher and stable yield under moderate to severe stress conditions. These genotypes are postulated to be better adapted to stress environment such as upland and aerobic environments. Importantly, the score index selection method offers improved precision than the conventional breeding selection method in identifying genotypes that are well-suited to a range of stress levels within the target environment.展开更多
Employing DEA model and Malmquist productivity index, this paper probes into the urban efficiencies of 24 typical resources-based cities in China and their changes from 2000 to 2008. The research finds that the overal...Employing DEA model and Malmquist productivity index, this paper probes into the urban efficiencies of 24 typical resources-based cities in China and their changes from 2000 to 2008. The research finds that the overall efficiencies of the resources-based cities are just at a general level, and only a few of them reach the optimal level. The scale efficiency is the major determining factor of the achievement of overall efficiency, the effect of which, nevertheless, is reducing. From the perspective of classification characteristics, the resources-based cities in northeastern region have been in the front rank in terms of overall efficiency, pure technical efficiency and scale efficiency. There is a certain positive correlation between urban population scale and urban efficiency. The analysis of urban efficiency changes shows that the changes in overall efficiency of resources-based cities from 2000 to 2008 had a weak improving tendency. Both the technical change index and productivity change index decreased, indicating that the urban efficiency did not improve during this period, and the tendency of technical recession and productivity decline was obvious. In terms of the classification of urban efficiency changes, the urban overall efficiency improved in each of the four regions from 2000 to 2008, among which western region witnessed the greatest increase. Cities with different resource types have improved their urban overall efficiencies except steel-based cities. The urban overall efficiency increased in resources-based cities of different scales, with greater improvement in small and medium-sized cities than in big cities.展开更多
The border areas of the Tibetan Plateau and the neighboring mountainous areashave a high incidence of earthquakes with a magnitude greater than Ms 5.0, as well as havinga dense distribution of geological disasters suc...The border areas of the Tibetan Plateau and the neighboring mountainous areashave a high incidence of earthquakes with a magnitude greater than Ms 5.0, as well as havinga dense distribution of geological disasters such as collapses, landslides, and debris flows.Revealing the post-disaster economic development and recovery process is very importantfor enhancing disaster prevention and response capacity in order to formulate control policiesand recovery methods for post-disaster economic reconstruction based on economic resilience.Using long-term socioeconomic data and the autoregressive integrated moving average(ARIMA) model, this paper calculated the economic resilience index of the areas mostseverely affected by the Wenchuan Earthquake of 2008 and adopted the improved variablereturns to scale (VRS) date envelopment analysis (DEA) model and the Malmquist productivityindex to analyze the efficiency and effect of annual post-disaster recovery. The resultsshow that: (1) the economic resilience index of the areas most severely affected by theWenchuan Earthquake was 0.877. The earthquake resulted in a short-term economic recessionin the affected areas, but the economy returned to pre-quake levels within two years. Inaddition, the industrial economy was less resilient than agriculture and the service industry. (2)The comprehensive economic recovery efficiency of the disaster-stricken area in the yearfollowing the disaster was 0.603. The comprehensive efficiency, the pure technical efficiency,and the scale efficiency of the plain and hilly areas were significantly greater than those of theplateau and mountain areas. (3) The annual fluctuation in total factor productivity (TFP) followingthe disaster was considerable, and the economic recovery efficiency decreased significantly,resulting in a short-term economic recession. The TFP index returned to steadystate following decreases of 33.7% and 15.2%, respectively, in the two years following thedisaster. (4) The significant decrease in the post-disaster recovery efficiency was causedmainly by technological changes, and the renewal of the production system was the leading factor in determining the economic resilience following the disaster. With the decline in thescale of economic recovery following the earthquake, long-term economic recovery in thedisaster-stricken areas depended mainly on pure technical efficiency, and the improvement inthe latter was the driving force for maintaining the long-term growth of the post-disastereconomy. Therefore, according to the local characteristics of natural environment and economicsystem, the disaster-stricken areas need to actively change and readjust their economicstructures. At the same time, attention should be paid to updating the production systemto enhance the level of technological progress and give full play to the scale effects oflarge-scale capital, new facilities, human resources, and other investment factors followingthe disaster so as to enhance the impact of economic resilience and recovery efficiency inresponse to the disaster.展开更多
Soil loss tolerance (/) is the maximum rate of annual soil erosion that is tolerated and still allows a high level of crop productivity to be sustained economically and indefinitely. In the black soil region of Nort...Soil loss tolerance (/) is the maximum rate of annual soil erosion that is tolerated and still allows a high level of crop productivity to be sustained economically and indefinitely. In the black soil region of Northeast China, an empirically determined, default Tvalue of 200 (t/km2.a) is used for designing land restoration strategies for different types of soils. The ob- jective of this study was to provide a methodology to calculate a quantitative T for different black soil species. A field investigation was conducted to determine the typical soil profiles of 21 black soil species in the study area and a quantitative methodology based on a modified soil productivity index model was established to calculate the Tvalues. These values, which varied from 68 t/km2.a to 358 t/km2-a, yielded an average Tvalue of 141 t/km2.a for the 21 soil species. This is 29.5% lower than the current national standard T value. Two significant factors that influenced the T value were soil thickness and vulnerability to erosion. An acceptable reduction rate of soil productivity over a planned time period of 1% is recommended as necessary for maintaining long-term sustainable soil productivity. Compared with the cur- rently used of regional unified standard T value, the proposed method, which determines T using specific soil profile indices, has more practical implications for effective, sustainable management of soil and water conservation.展开更多
A vertex labeling f : V →Z2 of a simple graph G = (V, E) induces two edge labelings The friendly index set and the product-cordial index set of G are defined as the setsf is friendly}. In this paper we study and d...A vertex labeling f : V →Z2 of a simple graph G = (V, E) induces two edge labelings The friendly index set and the product-cordial index set of G are defined as the setsf is friendly}. In this paper we study and determine the connection between the friendly index sets and product-cordial index sets of 2-regular graphs and generalized wheel graphs.展开更多
This paper aims to measure the productivity of academic journals in the field of management science and operations research on the basis of a data envelopment analysis(DEA)-Malmquist approach.Using the empirical resul...This paper aims to measure the productivity of academic journals in the field of management science and operations research on the basis of a data envelopment analysis(DEA)-Malmquist approach.Using the empirical results,we make the following findings:(1)Compared with the DEA-CCR(Charnes,Cooper,Rhodes)model,the DEA-BCC(Banker,Charnes,Cooper)model may overestimate the performance of journals with a shorter cited half-life and fewer articles,and may underestimate the performance of journals with a longer cited half-life and more articles;(2)The average performance of journals in the management science and operations research field progressed by 1.8%during 2007-2014,which was a result of the frontier-shift effect;(3)The gap between the best journals on the DEA frontier and the rest of the journals is increasing because the best journals grow relatively faster;(4)High-level journals have made more progress and their performance is more stable,and the difference between high-level journals was also smaller during 2007-2014;and,(5)A higher total factor productivity value corresponds to higher Association of Business Schools rankings for certain journals.展开更多
With the development of China’s economy,environmental pollution has become cumulatively serious.The primary source of environmental pollution is thermal power generation,which has attracted the attention of governmen...With the development of China’s economy,environmental pollution has become cumulatively serious.The primary source of environmental pollution is thermal power generation,which has attracted the attention of governments and academia in recent years.To effectively reduce environmental pollution,research should study how to constrain the undesirable output of thermal power plants,that is,to limit the total undesirable output of the plants to a certain fixed sum.However,few studies have suggested that these undesirable outputs should be fixed-sum outputs.Moreover,no previous research publication about thermal power plants has analyzed their environmental performance changes.To address these gaps,a novel Malmquist-DEA approach is proposed for evaluate the environmental performance of thermal power plants in this paper.This approach generalizes the equilibrium efficient frontier DEA model with fixed-sum undesirable outputs and incorporates the model into the Malmquist productivity index(MPI).The authors apply this approach to the analysis of provincial thermal power plant environmental performance in China and analyze such plants’trends based on panel data from2011 to 2014.The empirical research shows that the environmental performance of regional thermal power plants was positively affected by efficiency change and negatively affected by technical change.Finally,the authors provide policy suggestions based on our findings.展开更多
The objective of this paper is introducing practical solutions for stabilized pseudo-steady state productivity index and pressure behaviors and flow regimes of multiple vertical wells depleting closed rectangular rese...The objective of this paper is introducing practical solutions for stabilized pseudo-steady state productivity index and pressure behaviors and flow regimes of multiple vertical wells depleting closed rectangular reservoirs.It introduces full understanding of reservoir performance during transient and pseudo-steady state flow using pressure and pressure derivative patterns and productivity index and productivity index derivative schemes.The practical solutions proposed in this study are relied on a new approach for accurate estimation of starting time of pseudo-steady state flow and stabilized productivity index by applying productivity index derivative that converges mathematically to zero at the beginning of this flow.It is also an attempt for pointing out the optimal reservoir configuration that can give maximum stabilized pseudo-steady state productivity index for different wellbore types and distributions in the drainage area.Several analytical models are used in this study for describing pressure drop and productivity index behavior of multiple vertical wells considering different reservoir configurations and different wellbore types and locations.These wells were assumed either fully or partially penetrate the formations.These pressure models are justified to generate two pressure derivatives,one represents the derivative of time dependent pressure drop and the second represents the derivative of time-invariant pressure drop.The two derivatives are used for determining the starting time of pseudo-steady state flow and stabilized productivity index when both converge and mathematically become identical.These models are used also to generate several plots for time-invariant or stabilized pseudo-steady state productivity index for different reservoir geometries considering different wellbore conditions.The maximum stabilized productivity index is illustrated in these plots and several analytical models for the expected flow regimes are developed using pressure and pressure derivative behaviors of different reservoirs and wellbore conditions.The outcomes of this study are summarized in:1)Developing new analytical solutions for pressure distribution in porous media drained by multiple vertical wells.2)Developing new practical solution for estimating stabilized pseudo-steady state productivity index.3)Understanding pressure,pressure derivative,and productivity index behavior of finite acting reservoir depleted by multiple vertical wells during transient and pseudo-steady state production.4)Investigating the impacts of different reservoir configurations and wellbore sizes and locations as well as partial penetration on stabilized pseudo-steady state productivity index.The novel points in this study are:1)The optimum reservoir configuration that gives the maximum stabilized productivity index is the rectangular shape reservoir with reservoir length to width ratio of(2-4).2)Starting time of pseudo-steady state and stabilized productivity index are impacted by wellbore numbers,sizes,and locations.3)Starting time of pseudo-steady state flow is not affected by partial penetration ratio,however,stabilized productivity index is affected by this ratio.4)Five spots pattern gives the maximum productivity index compared with other wellbore distribution patterns.5)Productivity index of diagonally distributed wellbores is greater than the index of wellbores distributed along reservoir length.展开更多
This paper introduces some index concepts used in the study of economical theoryand summarizes some conclusions on the consistency between linear homogeneous production (or cost)function and index formula. In the last...This paper introduces some index concepts used in the study of economical theoryand summarizes some conclusions on the consistency between linear homogeneous production (or cost)function and index formula. In the last section , the authors show the consistency between nonlinearhomogeneous production and index formula and fill the gap in this field.展开更多
Background:Decisions regarding the conversion of land from an existing crop to bioenergy crops are critical for the sustainable production of both food and fuels.This study seeks to establish criteria for delineating ...Background:Decisions regarding the conversion of land from an existing crop to bioenergy crops are critical for the sustainable production of both food and fuels.This study seeks to establish criteria for delineating land as“economically marginal”,and thus suited for growing switchgrass.Methods:In this case study of an Illinois agricultural field,the profitability of switchgrass,with farmgate prices of$44 Mg−1,$66 Mg−1,or$88 Mg−1,was compared to corn and soybean crop prices.Further,the study also evaluates the profitability of switchgrass when replacing corn‐based yield estimates from the Soil Productivity Index(SPI)of Illinois.Results:Based on a dry‐matter yield of 10.45 Mg ha−1,switchgrass can compete with soybeans only at the high price of$88 Mg−1,but depending on location,can compete with corn at$66 Mg−1.Across Illinois,at$88 ha−1,all Illinois land with SPI<100%and 95%of land under SPI class C(SPI 100–116)is profitable under switchgrass.Switchgrass may not be profitable relative to corn grown in the SPI class A(SPI>133)and only 7%of class B(SPI 117–132).Conclusions:Our results show that land with drainage and erosion limitations is economically marginal when corn and soybean yields are low,and the farmgate price for switchgrass is greater than$66 Mg−1.However,this may not be possible on land where switchgrass is replacing frequent soybean rotations(corn–soybean ratio≤1).Land used to produce only soybeans may only be marginal at the farmgate price of$88 Mg−1.Further studies need to be conducted to identify how much land can be converted to switchgrass without harming corn production.展开更多
基金supported by the National Natural Science Foundation of China(No.71473099)
文摘China implemented the public hospital reform in 2012. This study utilized bootstrapping data envelopment analysis(DEA) to evaluate the technical efficiency(TE) and productivity of county public hospitals in Eastern, Central, and Western China after the 2012 public hospital reform. Data from 127 county public hospitals(39, 45, and 43 in Eastern, Central, and Western China, respectively) were collected during 2012–2015. Changes of TE and productivity over time were estimated by bootstrapping DEA and bootstrapping Malmquist. The disparities in TE and productivity among public hospitals in the three regions of China were compared by Kruskal–Wallis H test and Mann–Whitney U test. The average bias-corrected TE values for the four-year period were 0.6442, 0.5785, 0.6099, and 0.6094 in Eastern, Central, and Western China, and the entire country respectively, with average non-technical efficiency, low pure technical efficiency(PTE), and high scale efficiency found. Productivity increased by 8.12%, 0.25%, 12.11%, and 11.58% in China and its three regions during 2012–2015, and such increase in productivity resulted from progressive technological changes by 16.42%, 6.32%, 21.08%, and 21.42%, respectively. The TE and PTE of the county hospitals significantly differed among the three regions of China. Eastern and Western China showed significantly higher TE and PTE than Central China. More than 60% of county public hospitals in China and its three areas operated at decreasing return scales. There was a considerable space for TE improvement in county hospitals in China and its three regions. During 2012–2015, the hospitals experienced progressive productivity; however, the PTE changed adversely. Moreover, Central China continuously achieved a significantly lower efficiency score than Eastern and Western China. Decision makers and administrators in China should identify the causes of the observed inefficiencies and take appropriate measures to increase the efficiency of county public hospitals in the three areas of China, especially in Central China.
文摘Although mining production depends on various equipments, significant amount of production loss can be attributed a specific equipment or fleet. Bottleneck is defined not only by production loss but also by our satisfaction from the equipment. The user satisfaction could be measured as machine effectiveness.Mining literatures on performance improvement and optimization of equipment operations assert importance of availability, utilization and production performance as key parameters. These three parameters are useful for evaluating effectiveness of equipment. Mine production index(MPI), which can represent the effect of these factors, has been applied for continuous operation in mining. MPI uses Fuzzy Delphi Analytical Hierarchy Process to determine importance of each three parameter for individual equipment. A case study in a Swedish open pit mine was done to evaluate the field application of MPI.The results reveal that crusher is the bottleneck equipment in studied mine. As a methodical approach,an algorithm which uses MPI and detects bottleneck in continuous mining operation has been proposed.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences,Pan-Third Pole Environment Study for a Green Silk Road(Pan-TPE)of China(XDA2004030202)Shanghai Cooperation and the Organization Science and Technology Partnership of China(2021E01019)。
文摘Hydrothermal condition is mismatched in arid and semi-arid regions,particularly in Central Asia(including Kazakhstan,Kyrgyzstan,Tajikistan,Uzbekistan,and Turkmenistan),resulting many environmental limitations.In this study,we projected hydrothermal condition in Central Asia based on bias-corrected multi-model ensembles(MMEs)from the Coupled Model Intercomparison Project Phase 6(CMIP6)under four Shared Socioeconomic Pathway and Representative Concentration Pathway(SSP-RCP)scenarios(SSP126(SSP1-RCP2.6),SSP245(SSP2-RCP4.5),SSP460(SSP4-RCP6.0),and SSP585(SSP5-RCP8.5))during 2015-2100.The bias correction and spatial disaggregation,water-thermal product index,and sensitivity analysis were used in this study.The results showed that the hydrothermal condition is mismatched in the central and southern deserts,whereas the region of Pamir Mountains and Tianshan Mountains as well as the northern plains of Kazakhstan showed a matched hydrothermal condition.Compared with the historical period,the matched degree of hydrothermal condition improves during 2046-2075,but degenerates during 2015-2044 and 2076-2100.The change of hydrothermal condition is sensitive to precipitation in the northern regions and the maximum temperatures in the southern regions.The result suggests that the optimal scenario in Central Asia is SSP126 scenario,while SSP585 scenario brings further hydrothermal contradictions.This study provides scientific information for the development and sustainable utilization of hydrothermal resources in arid and semi-arid regions under climate change.
文摘Climate warming is expected to influence forest growth,composition and distribution.However,accurately estimating and predicting forest biomass,potential productivity or forest growth is still a challenge for forest managers dealing with land-use at the stand to regional levels.In the present study,we predicted the potential productivity(PP)of forest under current and future climate scenarios(RCP2.6,RCP4.5,RCP6.0 and RCP8.5)in Jilin province,northeastern China by using Paterson’s Climate Vegetation and Productivity(CVP)index model.The PP was validated by comparing it with the mean and maximum net primary production calculated from light energy utilization(GLM_PEM).Our results indicated that using the CVP index model is partially valid for predicting the potential forest productivity in northeastern China.PP exhibited obvious spatial heterogeneity varying from 4.6 to 8.9 m3 ha-1 year-1 with an increasing tendency from northwest to southeast driven by the precipitation across the region.The number of vegetation-active months,precipitation and insolation coefficient were identified as the primary factors affecting PP,but no significant relationship was found for warmest temperature or temperature fluctuation.Under future climate scenarios,PP across the Jilin Province is expected to increase from 1.38%(RCP2.6 in 2050)to 15.30%(RCP8.5 in 2070),especially in the eastern Songnen Plain(SE)for the RCP8.5 scenarios.
基金This research was supported in part by the Ministry of Science and Technology in Taiwan under Grants MOST 109-2410-H-027-012-MY2.
文摘During the last decade,the food and beverage industry has been one of the most significant and prioritized industries that contributed to the economic growth in Vietnam.Therefore,how to enhance the performance of food and beverage firms has become a critical factor for Vietnam’s economic development.This research aims to use the data envelopment analysis(DEA)and the Malmquist productivity index(MPI)to assess changes in operational performance and productivity of listed lead food and beverage firms in Vietnam during the period between 2015 and 2020.The obtained results reveal that Vietnamese food and beverage firms were generally inefficient between 2015 and 2020 because the number of relatively inefficient companies was higher than the relatively efficient ones in each year between 2015 and 2020.The MPI findings indicate the growth in productivity during the study period as a result of technological progress.By integrating the findings of the relative efficiency and productivity change,this study creates five decision-making matrixes for five periods,respectively,from 2015 to 2020 to position the food and beverage firms in each sector.The analytical results provide instructions to senior managers on developing strategy for increasing efficiency of food and beverage listed companies in Vietnam.
文摘The calculation of the overall profit Malmquist productivity index(MPI)requires precise and accurate information on the input,output,input-output prices of each decision making unit(DMU).However,in many situations,some inputs and/or outputs and input-output prices are imprecise.As such,we consider the overall profit MPI problem when the input,output,and input-output prices are imprecise and vary over intervals,showing that method(MCM 54:2827–2838,2011)has some shortfalls.To remedy these shortfalls,we propose another method for measuring the overall profit MPI when the inputs,outputs,and price vectors vary over intervals.That is,to calculate the overall profit efficiency intervals,cone-ratio data envelopment analysis models can be applied to the incorporated information as weight restrictions.Further,we provide a new approach to calculating the upper bound of the overall profit efficiency of each DMU.A numerical example is provided for illustrating the proposed method.
基金Supported by the National Social Science Foundation of China(16BJY136) in 2016the Consultant Project of Chinese Academy of Engineering(07-XY-003) in 2015
文摘Agricultural product price index insurance is a kind of index insurance. It avoids defects of traditional agricultural insurance,such as moral hazards,adverse selection,and high management cost. On the basis of studying agricultural product price index insurance of all areas of China,this paper analyzed characteristics of agricultural product price index insurance from object selection,product object,premium design,and policy support,and discussed feasibility of extending agricultural product price index insurance in an all-round way.
基金supported by a FONDECYT——World Bank fund for the project 017-2020a Newton Fund Impact Scheme ID 630222342 under the Newton-Paulet Fund partnership。
文摘In Asia, the rice crop sustains millions of people. However, growing demand for this crop needs to be met while simultaneously reducing its water consumption to cope with the effects of climate change. Lowland cropping systems are the most common and productive but have particularly high water requirements. High-yielding rice genotypes adapted to drier environments(such as rainfed or aerobic rice ecosystems) are needed to increase the water use efficiency of cropping. Identifying these genotypes requires fast and more accurate selection methods. It is hypothesized that applying a new quantitative selection method(the score index selection method), can usefully compare rice yield responses over different years and stress intensities to select genotypes more rapidly and efficiently. Applying the score index to previously published rice yield data for 39 genotypes grown in no-stress and two stress environments, identified three genotypes(ARB 8, IR55419-04 and ARB 7) with higher and stable yield under moderate to severe stress conditions. These genotypes are postulated to be better adapted to stress environment such as upland and aerobic environments. Importantly, the score index selection method offers improved precision than the conventional breeding selection method in identifying genotypes that are well-suited to a range of stress levels within the target environment.
基金National Natural Science Foundation of China, No.40701044 National Key Technology R&D Program, No.2008BAH31B01
文摘Employing DEA model and Malmquist productivity index, this paper probes into the urban efficiencies of 24 typical resources-based cities in China and their changes from 2000 to 2008. The research finds that the overall efficiencies of the resources-based cities are just at a general level, and only a few of them reach the optimal level. The scale efficiency is the major determining factor of the achievement of overall efficiency, the effect of which, nevertheless, is reducing. From the perspective of classification characteristics, the resources-based cities in northeastern region have been in the front rank in terms of overall efficiency, pure technical efficiency and scale efficiency. There is a certain positive correlation between urban population scale and urban efficiency. The analysis of urban efficiency changes shows that the changes in overall efficiency of resources-based cities from 2000 to 2008 had a weak improving tendency. Both the technical change index and productivity change index decreased, indicating that the urban efficiency did not improve during this period, and the tendency of technical recession and productivity decline was obvious. In terms of the classification of urban efficiency changes, the urban overall efficiency improved in each of the four regions from 2000 to 2008, among which western region witnessed the greatest increase. Cities with different resource types have improved their urban overall efficiencies except steel-based cities. The urban overall efficiency increased in resources-based cities of different scales, with greater improvement in small and medium-sized cities than in big cities.
基金Second Tibetan Plateau Scientific Expedition and Research Program(STEP),No.2019QZKK0406National Natural Science Foundation of China,No.41807510,No.41501139。
文摘The border areas of the Tibetan Plateau and the neighboring mountainous areashave a high incidence of earthquakes with a magnitude greater than Ms 5.0, as well as havinga dense distribution of geological disasters such as collapses, landslides, and debris flows.Revealing the post-disaster economic development and recovery process is very importantfor enhancing disaster prevention and response capacity in order to formulate control policiesand recovery methods for post-disaster economic reconstruction based on economic resilience.Using long-term socioeconomic data and the autoregressive integrated moving average(ARIMA) model, this paper calculated the economic resilience index of the areas mostseverely affected by the Wenchuan Earthquake of 2008 and adopted the improved variablereturns to scale (VRS) date envelopment analysis (DEA) model and the Malmquist productivityindex to analyze the efficiency and effect of annual post-disaster recovery. The resultsshow that: (1) the economic resilience index of the areas most severely affected by theWenchuan Earthquake was 0.877. The earthquake resulted in a short-term economic recessionin the affected areas, but the economy returned to pre-quake levels within two years. Inaddition, the industrial economy was less resilient than agriculture and the service industry. (2)The comprehensive economic recovery efficiency of the disaster-stricken area in the yearfollowing the disaster was 0.603. The comprehensive efficiency, the pure technical efficiency,and the scale efficiency of the plain and hilly areas were significantly greater than those of theplateau and mountain areas. (3) The annual fluctuation in total factor productivity (TFP) followingthe disaster was considerable, and the economic recovery efficiency decreased significantly,resulting in a short-term economic recession. The TFP index returned to steadystate following decreases of 33.7% and 15.2%, respectively, in the two years following thedisaster. (4) The significant decrease in the post-disaster recovery efficiency was causedmainly by technological changes, and the renewal of the production system was the leading factor in determining the economic resilience following the disaster. With the decline in thescale of economic recovery following the earthquake, long-term economic recovery in thedisaster-stricken areas depended mainly on pure technical efficiency, and the improvement inthe latter was the driving force for maintaining the long-term growth of the post-disastereconomy. Therefore, according to the local characteristics of natural environment and economicsystem, the disaster-stricken areas need to actively change and readjust their economicstructures. At the same time, attention should be paid to updating the production systemto enhance the level of technological progress and give full play to the scale effects oflarge-scale capital, new facilities, human resources, and other investment factors followingthe disaster so as to enhance the impact of economic resilience and recovery efficiency inresponse to the disaster.
基金Foundation: National Natural Science Foundation of China, No.40671111 No.41101267 Nonprofit Sector Special Funds of the Ministry of Water Resources of China, No.2010332030
文摘Soil loss tolerance (/) is the maximum rate of annual soil erosion that is tolerated and still allows a high level of crop productivity to be sustained economically and indefinitely. In the black soil region of Northeast China, an empirically determined, default Tvalue of 200 (t/km2.a) is used for designing land restoration strategies for different types of soils. The ob- jective of this study was to provide a methodology to calculate a quantitative T for different black soil species. A field investigation was conducted to determine the typical soil profiles of 21 black soil species in the study area and a quantitative methodology based on a modified soil productivity index model was established to calculate the Tvalues. These values, which varied from 68 t/km2.a to 358 t/km2-a, yielded an average Tvalue of 141 t/km2.a for the 21 soil species. This is 29.5% lower than the current national standard T value. Two significant factors that influenced the T value were soil thickness and vulnerability to erosion. An acceptable reduction rate of soil productivity over a planned time period of 1% is recommended as necessary for maintaining long-term sustainable soil productivity. Compared with the cur- rently used of regional unified standard T value, the proposed method, which determines T using specific soil profile indices, has more practical implications for effective, sustainable management of soil and water conservation.
文摘A vertex labeling f : V →Z2 of a simple graph G = (V, E) induces two edge labelings The friendly index set and the product-cordial index set of G are defined as the setsf is friendly}. In this paper we study and determine the connection between the friendly index sets and product-cordial index sets of 2-regular graphs and generalized wheel graphs.
基金supported by the National Natural Science Foundation of China(NSFC,Nos.71201158,71671181)Hunan Province Social Science Achievement Evaluation Committee(2017,No.GLX195).
文摘This paper aims to measure the productivity of academic journals in the field of management science and operations research on the basis of a data envelopment analysis(DEA)-Malmquist approach.Using the empirical results,we make the following findings:(1)Compared with the DEA-CCR(Charnes,Cooper,Rhodes)model,the DEA-BCC(Banker,Charnes,Cooper)model may overestimate the performance of journals with a shorter cited half-life and fewer articles,and may underestimate the performance of journals with a longer cited half-life and more articles;(2)The average performance of journals in the management science and operations research field progressed by 1.8%during 2007-2014,which was a result of the frontier-shift effect;(3)The gap between the best journals on the DEA frontier and the rest of the journals is increasing because the best journals grow relatively faster;(4)High-level journals have made more progress and their performance is more stable,and the difference between high-level journals was also smaller during 2007-2014;and,(5)A higher total factor productivity value corresponds to higher Association of Business Schools rankings for certain journals.
基金supported by the National Natural Science Foundation of China under Grant Nos.72071192,71671172the Anhui Provincial Quality Engineering Teaching and Research Project under Grant No.2020jyxm2279+2 种基金the Anhui University and Enterprise Cooperation Practice Education Base Project under Grant No.2019sjjd02Teaching and Research Project of USTC(2019xjyxm019,2020ycjg08)the Fundamental Research Funds for the Central Universities(WK2040000027)。
文摘With the development of China’s economy,environmental pollution has become cumulatively serious.The primary source of environmental pollution is thermal power generation,which has attracted the attention of governments and academia in recent years.To effectively reduce environmental pollution,research should study how to constrain the undesirable output of thermal power plants,that is,to limit the total undesirable output of the plants to a certain fixed sum.However,few studies have suggested that these undesirable outputs should be fixed-sum outputs.Moreover,no previous research publication about thermal power plants has analyzed their environmental performance changes.To address these gaps,a novel Malmquist-DEA approach is proposed for evaluate the environmental performance of thermal power plants in this paper.This approach generalizes the equilibrium efficient frontier DEA model with fixed-sum undesirable outputs and incorporates the model into the Malmquist productivity index(MPI).The authors apply this approach to the analysis of provincial thermal power plant environmental performance in China and analyze such plants’trends based on panel data from2011 to 2014.The empirical research shows that the environmental performance of regional thermal power plants was positively affected by efficiency change and negatively affected by technical change.Finally,the authors provide policy suggestions based on our findings.
文摘The objective of this paper is introducing practical solutions for stabilized pseudo-steady state productivity index and pressure behaviors and flow regimes of multiple vertical wells depleting closed rectangular reservoirs.It introduces full understanding of reservoir performance during transient and pseudo-steady state flow using pressure and pressure derivative patterns and productivity index and productivity index derivative schemes.The practical solutions proposed in this study are relied on a new approach for accurate estimation of starting time of pseudo-steady state flow and stabilized productivity index by applying productivity index derivative that converges mathematically to zero at the beginning of this flow.It is also an attempt for pointing out the optimal reservoir configuration that can give maximum stabilized pseudo-steady state productivity index for different wellbore types and distributions in the drainage area.Several analytical models are used in this study for describing pressure drop and productivity index behavior of multiple vertical wells considering different reservoir configurations and different wellbore types and locations.These wells were assumed either fully or partially penetrate the formations.These pressure models are justified to generate two pressure derivatives,one represents the derivative of time dependent pressure drop and the second represents the derivative of time-invariant pressure drop.The two derivatives are used for determining the starting time of pseudo-steady state flow and stabilized productivity index when both converge and mathematically become identical.These models are used also to generate several plots for time-invariant or stabilized pseudo-steady state productivity index for different reservoir geometries considering different wellbore conditions.The maximum stabilized productivity index is illustrated in these plots and several analytical models for the expected flow regimes are developed using pressure and pressure derivative behaviors of different reservoirs and wellbore conditions.The outcomes of this study are summarized in:1)Developing new analytical solutions for pressure distribution in porous media drained by multiple vertical wells.2)Developing new practical solution for estimating stabilized pseudo-steady state productivity index.3)Understanding pressure,pressure derivative,and productivity index behavior of finite acting reservoir depleted by multiple vertical wells during transient and pseudo-steady state production.4)Investigating the impacts of different reservoir configurations and wellbore sizes and locations as well as partial penetration on stabilized pseudo-steady state productivity index.The novel points in this study are:1)The optimum reservoir configuration that gives the maximum stabilized productivity index is the rectangular shape reservoir with reservoir length to width ratio of(2-4).2)Starting time of pseudo-steady state and stabilized productivity index are impacted by wellbore numbers,sizes,and locations.3)Starting time of pseudo-steady state flow is not affected by partial penetration ratio,however,stabilized productivity index is affected by this ratio.4)Five spots pattern gives the maximum productivity index compared with other wellbore distribution patterns.5)Productivity index of diagonally distributed wellbores is greater than the index of wellbores distributed along reservoir length.
文摘This paper introduces some index concepts used in the study of economical theoryand summarizes some conclusions on the consistency between linear homogeneous production (or cost)function and index formula. In the last section , the authors show the consistency between nonlinearhomogeneous production and index formula and fill the gap in this field.
基金supported by the University of Illinois at Urbana‐Champaign Hatch Project(1001878)the US Department of Energy,Energy Efficiency and Renewable Energy(EERE),Bioenergy Technologies Office(BETO),grant number DE‐EE0008521.
文摘Background:Decisions regarding the conversion of land from an existing crop to bioenergy crops are critical for the sustainable production of both food and fuels.This study seeks to establish criteria for delineating land as“economically marginal”,and thus suited for growing switchgrass.Methods:In this case study of an Illinois agricultural field,the profitability of switchgrass,with farmgate prices of$44 Mg−1,$66 Mg−1,or$88 Mg−1,was compared to corn and soybean crop prices.Further,the study also evaluates the profitability of switchgrass when replacing corn‐based yield estimates from the Soil Productivity Index(SPI)of Illinois.Results:Based on a dry‐matter yield of 10.45 Mg ha−1,switchgrass can compete with soybeans only at the high price of$88 Mg−1,but depending on location,can compete with corn at$66 Mg−1.Across Illinois,at$88 ha−1,all Illinois land with SPI<100%and 95%of land under SPI class C(SPI 100–116)is profitable under switchgrass.Switchgrass may not be profitable relative to corn grown in the SPI class A(SPI>133)and only 7%of class B(SPI 117–132).Conclusions:Our results show that land with drainage and erosion limitations is economically marginal when corn and soybean yields are low,and the farmgate price for switchgrass is greater than$66 Mg−1.However,this may not be possible on land where switchgrass is replacing frequent soybean rotations(corn–soybean ratio≤1).Land used to produce only soybeans may only be marginal at the farmgate price of$88 Mg−1.Further studies need to be conducted to identify how much land can be converted to switchgrass without harming corn production.