The energy sector in Poland is the source of 81% of greenhouse gas（GHG） emissions. Poland,among other European Union countries, occupies a leading position with regard to coal consumption. Polish energy sector activ...The energy sector in Poland is the source of 81% of greenhouse gas（GHG） emissions. Poland,among other European Union countries, occupies a leading position with regard to coal consumption. Polish energy sector actively participates in efforts to reduce GHG emissions to the atmosphere, through a gradual decrease of the share of coal in the fuel mix and development of renewable energy sources. All evidence which completes the knowledge about issues related to GHG emissions is a valuable source of information. The article presents the results of modeling of GHG emissions which are generated by the energy sector in Poland. For a better understanding of the quantitative relationship between total consumption of primary energy and greenhouse gas emission, multiple stepwise regression model was applied. The modeling results of CO2 emissions demonstrate a high relationship（0.97） with the hard coal consumption variable. Adjustment coefficient of the model to actual data is high and equal to 95%. The backward step regression model, in the case of CH4 emission, indicated the presence of hard coal（0.66）, peat and fuel wood（0.34）, solid waste fuels, as well as other sources（- 0.64） as the most important variables. The adjusted coefficient is suitable and equals R2= 0.90. For N2 O emission modeling the obtained coefficient of determination is low and equal to 43%. A significant variable influencing the amount of N2 O emission is the peat and wood fuel consumption.展开更多
This paper intends to provide an in-depth and comprehensive analysis of China＇s service sector reform during 1978-2016 and characterize the model of the service sector reform. Due to unique national conditions and de...This paper intends to provide an in-depth and comprehensive analysis of China＇s service sector reform during 1978-2016 and characterize the model of the service sector reform. Due to unique national conditions and development journey, China＇s service sector reform was carried out in the context of China＇s overall reform and opening-up program based on non-industrial motivations with a pragmatic approach to improve both people＇s livelihood and efficiency and address practical problems facing China in various stages of its development, putting aside theoretical controversies. How to further improve the model of China＇s service sector reform that came into shape in such a unique historical context and advance service sector reform is an important yet arduous task.展开更多
In this paper, a two\|sector growth model is given. The labor force transfer process from agricultural sector to industrial sector is exogenous determined. By introducing the labor force transferring function, a two\|...In this paper, a two\|sector growth model is given. The labor force transfer process from agricultural sector to industrial sector is exogenous determined. By introducing the labor force transferring function, a two\|dimension nonautonomous differential equation is obtained. The results of the model manifest that the labor force transfer delays industrial sector growth and accelerates the agricultural sector growth. It is proved that the solution of the model is asymptotic stable. By the numerical analysis, the economic growth and labor force transfer is presented under the specific parameters.展开更多
China has huge differences among its regions in terms of socio-economic development, industrial structure, natural resource endowments, and technological advancement. These differences have created complicated linkage...China has huge differences among its regions in terms of socio-economic development, industrial structure, natural resource endowments, and technological advancement. These differences have created complicated linkages between regions in China. In this study, building upon gravity model and location quotient techniques, we develop a sector-specific model to estimate inter-provincial trade flows, which is the base for making a multi-regional input-output table. In the model, we distinguish sectors with less intra-sector input from those with larger intra-sector input, and assume that the former sectors tend to compete among regions while the latter tend to cooperate among regions. Then we apply this new method of inter-regional trade estimation to three sectors： food and tobacco, metal smelting and proc- essing, and electrical equipment. The results show that selection of bandwidth has a significant impact on the assessment of inter-regional trade. Trade flows are more scattered with the increase of bandwidths. As a result, bandwidth reflects the spatial concentration of geo- graphical activities, which should be distinguishable for different industries. We conclude that the sector-specific spatial model can increase the credibility of estimates of inter-regional trade flows.展开更多
Terminal airspace(TMA)is the airspace centering several military and civil aviation airports with complex route structure,limited airspace resources,traffic flow,difficult management and considerable airspace complexi...Terminal airspace(TMA)is the airspace centering several military and civil aviation airports with complex route structure,limited airspace resources,traffic flow,difficult management and considerable airspace complexity.A scientific and rational sectorization of TMA can optimize airspace resources,and sufficiently utilize the control of human resources to ensure the safety of TMA.The functional sectorization model was established based on the route structure of arriving and departing aircraft as well as controlling requirements.Based on principles of sectorization and topological relations within a network,the arrival and departure sectorization model was established,using tree based ant colony algorithm(ACO)searching.Shanghai TMA was taken as an example to be sectorizaed,and the result showed that this model was superior to traditional ones when arrival and departure routes were separated at dense airport terminal airspace.展开更多
In this paper, we subdivide the sample of manufacturing companies listed in two stock exchanges in China from the year 2000 to 2009 into two categories： the firms which adopted the similar financial models and those ...In this paper, we subdivide the sample of manufacturing companies listed in two stock exchanges in China from the year 2000 to 2009 into two categories： the firms which adopted the similar financial models and those which did not. Then we use t-test and nonparametric test to explore the differences between the two sub-samples in cash management, assets and liabilities structures, assets turnover ratios, profitability, liquidity and growth rates. The results show that the former has shorter Cash Conversion Cycle （CCC）, quicker assets turnover, higher Debt Ratio （DR）, higher growth rate and thus has better profitability. In addition, the regression analysis results further demonstrate that Return on Invested Capital （ROIC） of similar-financial-model firms are positively related to Net Profit Margin （NPM） （p 〈 0.01）, and negatively to CCC （p 〈 0.01）, Interest Expense Ratio （IER） （p 〈 0.01）, the Ratio of Interest-Bearing Debt to Total Liabilities （IBDR） （p 〈 0.01） and the ratio of Net Receivables to Sales Revenue （NRSR） （p 〈 0.01）. Moreover, negative relationship between ROIC and dummy variable GROUP implies that the former has better profitability than the latter.展开更多
The energy sector is the second largest emitter of greenhouse (GHG) gases in Kenya, emitting about 31.2% of GHG emissions in the country. The aim of this study was to model Kenya’s GHG emissions by the energy sector ...The energy sector is the second largest emitter of greenhouse (GHG) gases in Kenya, emitting about 31.2% of GHG emissions in the country. The aim of this study was to model Kenya’s GHG emissions by the energy sector using ARIMA models for forecasting future values. The data used for the study was that of Kenya’s GHG emissions by the energy sector for the period starting from 1970 to 2022 obtained for the International Monetary Fund (IMF) database that was split into training and testing sets using the 80/20 rule for modelling purposes. The best specification for the ARIMA model was identified using Akaike Information Criterion (AIC), root mean squared error (RMSE), mean absolute error (MAE), mean absolute percentage error (MAPE) and mean absolute scaled error (MASE). ARIMA (1, 1, 1) was identified as the best model for modelling Kenya’s GHG emissions and forecasting future values. Using this model, Kenya’s GHG emissions by the energy sector were forecasted to increase to a value of about 43.13 million metric tons of carbon dioxide equivalents by 2030. The study, therefore, recommends that Kenya should accelerate the adjustment of industry structure and improve the efficient use of energy, optimize the energy structure and accelerate development and promotion of energy-efficient products to reduce the emission of GHGs by the country’s energy sector.展开更多
Transport sector is cited among the key emitted sector.In Burkina Faso,road transport occupies more than 60%of the emissions of the entire transport sector.However,there is no model equation for greenhouse gases model...Transport sector is cited among the key emitted sector.In Burkina Faso,road transport occupies more than 60%of the emissions of the entire transport sector.However,there is no model equation for greenhouse gases modelling in transport sector.A methodology combining literature review and survey has been adopted to develop the simplified model equation in transport sector.The vehicle type survey allowed the identification of the type of vehicle and the literature review allowed the identification of the key parameters used for greenhouses gases modelling.The results revealed 10 vehicle types for road transport in Burkina Faso such as:Private cars,Public Transport/Buses,Special Vehicle(Ambulances,Fire bus,Funeral vehicles),other vehicle,Motorcycles,Wheeler,Rail,Van,Lorries and Truck Tractor.The keys parameters for greenhouse gases modelling are Fleet availability,Average annual distance travelled,Fuel Economy and Fuel emission factor.For all vehicle type identified simplified model equation was developed to support Burkina Faso,assessing greenhouse gases emission in the sector of transport.This approach could be replicated in other countries in the sub-Saharan Region.展开更多
Since reform and opening-up in 1978, changes in China's industrial structure have generally followed the pattern of "Kuznets facts" but still exhibits some unique characteristics, which led us to raise t...Since reform and opening-up in 1978, changes in China's industrial structure have generally followed the pattern of "Kuznets facts" but still exhibits some unique characteristics, which led us to raise the following three questions regarding China's structural transformation:(1) Why did the share of China's agricultural and manufacturing employment reduce/increase intermittently rather than continuously?(2) Why did the share of China's agricultural employment increase during certain periods? When the share of manufacturing employment reduced, why did the workforce reversely flow into agriculture rather than move to the service sector?(3) Why did growth in the share of China's service sector employment decelerate before reaching its peak? Why did the share of employment in the industrial sector suddenly increase after an abrupt decline? This paper creates a multisector economic growth model that contains non-homothetic preferences and differentiated productivity, and incorporates the "two drivers" therein for a demand-side estimation and analysis. The result shows that China's economic growth model driven by net export and investment is a critical factor for explaining the three questions regarding its structural transformation. This paper believes that only by implementing supply-side structural reforms, reducing the dependence on net export and investment, and achieving sustainable endogenous economic growth will China be able to expedite its industrial restructuring.展开更多
Interdependencies between critical infrastructures and the economy amplify the effects of damage caused by disasters.The growing interest in impacts beyond physical damage and community resilience has spurred a surge ...Interdependencies between critical infrastructures and the economy amplify the effects of damage caused by disasters.The growing interest in impacts beyond physical damage and community resilience has spurred a surge in literature on economic modeling methodologies for estimating indirect economic impacts of disasters and the recovery of economic activity over time.In this review,we present a framework for categorizing modeling approaches that assess indirect economic impacts across natural hazards and anthropogenic disasters such as cyber attacks.We first conduct a comparative analysis of macroeconomic models,focusing on the approaches capturing sectoral interdependencies.These include the Leontief Input-Output(I/O)model,the Inoperability Input-Output Model(IIM),the Dynamic Inoperability Input-Output Model(DIIM),the Adaptive Regional Input-Output(ARIO)model,and the Computable General Equilibrium(CGE)model and its extensions.We evaluate their applicability to disaster scenarios based on input data availability,the compatibility of model assumptions,and output capabilities.We also reveal the functional relationships of input data and output metrics across economic modeling approaches for inter-sectoral impacts.Furthermore,we examine how the damage mechanisms posed by different types of disasters translate into model inputs and impact modeling processes.This synthesis provides guidance for researchers and practitioners in selecting and configuring models based on specific disaster scenarios.It also identifies the gaps in the literature,including the need for a deeper understanding of model performance reliability,key drivers of economic outcomes in different disaster contexts,and the disparities in modeling approach applications across various hazard types.展开更多
Recently,the transportation sector in China has gradually become the main source of urban air pollution and primary driver of carbon emissions growth.Considering air pollutants and greenhouse gases come from the same ...Recently,the transportation sector in China has gradually become the main source of urban air pollution and primary driver of carbon emissions growth.Considering air pollutants and greenhouse gases come from the same emission sources,it is necessary to establish an updated high-resolution emission inventory for the transportation sector in Central China,themost polluted region in China.The inventory includes on-road mobile,non-roadmobile,oil storage and transportation,and covers 9 types of air pollutants and 3 types of greenhouse gases.Based on the Long-range Energy Alternatives Planning System(LEAP)model,the emissions of pollutants were predicted for the period from2020 to 2035 in different scenarios.Results showed that in 2020,emissions of SO_(2),NO_(x),CO,PM_(10),PM_(2.5),VOCs,NH_(3),BC,OC,CO_(2),CH_(4),and N_(2)O in Henan Province were 27.5,503.2,878.6,20.1,17.4,222.1,21.5,9.4,2.9,92,077.9,6.0,and 10.4 kilotons,respectively.Energy demand and pollutant emissions in Henan Province are simulated under four scenarios(Baseline Scenario(BS),Pollution Abatement Scenario(PA),Green Transportation Scenario(GT),and Reinforcing Low Carbon Scenario(RLC)).The collaborative emission reduction effect is most significant in the RLC scenario,followed by the GT scenario.By 2035,under the RLC scenario,energy consumption and emissions of SO_(2),NO_(x),CO,PM_(10),PM_(2.5),VOCs,NH_(3),CO_(2),CH_(4),and N_(2)O are projected to decrease by 72.0%,30.0%,55.6%,56.0%,38.6%,39.7%,51.5%,66.1%,65.5%,55.4%,and 52.8%,respectively.This study provides fundamental data support for subsequent numerical simulations.展开更多
The study constructs a low-carbon path analysis model of China's power sector based on TIMES model and presents a comparative analysis of carbon emissions under Reference,Low-Carbon and Enhanced Low-Carbon scenari...The study constructs a low-carbon path analysis model of China's power sector based on TIMES model and presents a comparative analysis of carbon emissions under Reference,Low-Carbon and Enhanced Low-Carbon scenarios,and the main difference of the three scenarios is manifested by policy selection and policy strength.The conclusions are drawn as follows:(1)The peak of carbon emission in China's power sector will range from 4.0 GtCO2 to 4.8 GtCO2,which implies an increment of 0.5e1.3 billion or 14%e35%from the 2015 levels.(2)Introducing carbon price is an effective way to inhibit coal power and promote non-fossil fuels and Carbon Capture,Utilization and Storage applications(CCUS).The carbon emission reduction effects will gradually increase with carbon price.When the carbon price attains to CN￥150 t1CO2,the CO2 emission can decrease by 36%than that without carbon price.(3)CCUS is one of important contributing factor to reduce CO2 emission in power sector.Generally speaking,the development of non-fossil fuels and energy efficiency improvement are two main drivers for carbon mitigation,but once the carbon price reaches up to CN￥106 t 1CO2,the CCUS will be required to equip with thermal power units and its contribution on carbon emission reduction will remarkably increase.When carbon price increases to CN￥150 t1CO2 in 2050,the application of CCUS will account for 44%of total emission reduction.(4)In the scenario with carbon price of CN￥150 t1CO2,power sector would be decarbonized significantly,and the CO2 intensity will be 0.22 kgCO2(kW h)1,but power sector is far from the goal that achieving net zero emission.In order to realize the long-term low greenhouse gas emission development goal that proposed by the Paris Agreement,more efforts are needed to be put to further reduce the carbon emission reduction of power sector.Based on the above scenario analysis,the study proposes four recommendations on the low-carbon development of China's power sector:(1)improve the energy efficiency proactively and optimize the energy structure of power sector gradually;(2)promote the low-carbon transition of power sector by using market-based mechanism like carbon emission trading scheme to internalize the external cost of carbon emission;(3)give more emphasis on and support to the CCUS application in power sector.展开更多
Climate change is expected to have substantial effects on agricultural productivity worldwide. However, these impacts will differ across commodities, locations and time periods. As a result, landowners will see change...Climate change is expected to have substantial effects on agricultural productivity worldwide. However, these impacts will differ across commodities, locations and time periods. As a result, landowners will see changes in relative returns that are likely to induce modifications in production practices and land allocation. In addition, regional variations in impacts can alter relative competitiveness across countries and lead to adjustments in international trade patterns. Thus in climate change impact studies it is likely useful to account for worldwide productivity effects. In this study, we investigate the implications of considering rest of world climate impacts on projections of the US agricultural exports. We chose to focus on the US because it is one of the largest agricultural exporters. To conduct our analyses, we consider four alternative climate scenarios, both with and without rest of world climate change impacts. Our results show that considering/ignoring rest of world climate impacts causes significant changes in the US production and exports projections. Thus we feel climate change impact studies should account not only for climate impacts in the country of focus but also on productivity in the rest of the world in order to capture effects on commodity markets and trade potential.展开更多
This paper deals with dynamic airspace sectorization （DAS） problem by an improved genetic algorithm （iGA）. A graph model is first constructed that represents the airspace static structure. Then the DAS problem is ...This paper deals with dynamic airspace sectorization （DAS） problem by an improved genetic algorithm （iGA）. A graph model is first constructed that represents the airspace static structure. Then the DAS problem is formulated as a graph-partitioning problem to balance the sector workload under the premise of ensuring safety. In the iGA, multiple populations and hybrid coding are applied to determine the optimal sector number and airspace sectorization. The sector constraints are well satisfied by the improved genetic operators and protect zones. This method is validated by being applied to the airspace of North China in terms of three indexes, which are sector balancing index, coordination workload index and sector average flight time index. The improvement is obvious, as the sector balancing index is reduced by 16.5 %, the coordination workload index is reduced by 11.2 %, and the sector average flight time index is increased by 11.4 % during the peak-hour traffic.展开更多
The electricity needs of populations in Cameroon are increasing and are still very inadequate. Companies, public buildings and households are facing frequent blackout which constrain development and social well-being....The electricity needs of populations in Cameroon are increasing and are still very inadequate. Companies, public buildings and households are facing frequent blackout which constrain development and social well-being. Therefore, the present work tried to forecast the electricity demand in the residential sector in Cameroon, in order to contribute significantly to the mastery of electricity consumption and highlight decision-makers in this sector. Six macroeconomics parameters covering the period 1994-2014 are used for these issues. Stationarity tests within gross domestic product, gross domestic product per capita, electricity consumption, population and numbers of subscribers and households respectively;reveal that all the series are I(1). Thus, the VAR (Vector Autoregressive) model has been retained to forecast the electricity demand until 2020. The cusum test and the cusum of squared test attest the stability of that model with a margin of error of 0.02%. Previsions are then more reliable and show that the electric request will skip from 1721 GWh in 2014 to more than 2481 GWh in 2020 approximatively, following a growing yearly rate of 5.36%. In order to reach its emergence, Cameroon ought to speed up its production in the domain of hydroelectric and thermal grid in order to meet the requirements in electric power in short and long term.展开更多
The basic aim of this paper is to study and analyze the current level of operational competitiveness of Pakistani Private Sector—Textile Manufacturing Enterprises. The subject research area will be probed on the basi...The basic aim of this paper is to study and analyze the current level of operational competitiveness of Pakistani Private Sector—Textile Manufacturing Enterprises. The subject research area will be probed on the basis of making cross reference comparison between the Pakistani Private Sector (PPS)—Textile Manufacturing Enterprises (TME) with the global Textile Manufacturing players in global manufacturing strategies databases. The results revealed that the “quality” is the most important competitive priority of the case PPS-TME and it also pointed towards having some competitive advantages in prospector group. However, it will take considerable amount of time for Pakistani Private Sector—Textile Manufacturing Enterprises to regain their previous global recognition and then further improve their operational competitiveness due to the weak and faulty organizational management structure and practices, currently being affected by nation’s political, economic, energy and security situation.展开更多
This paper uses an SBM-GML index model to assess Green Total Factor Productivity(GTFP)in China's carbon-intensive sectors and conducts an empirical investigation into which factors influence GTFP in these sectors....This paper uses an SBM-GML index model to assess Green Total Factor Productivity(GTFP)in China's carbon-intensive sectors and conducts an empirical investigation into which factors influence GTFP in these sectors.The GTFP in the carbon-intensive sectors experienced a decline between 2006 and 2011,followed by an upward trend beginning in 2012.Technological progress was the primary driver of GTFP growth,while business size was also a notable contributor.Irrational energy structures negatively influenced the high-quality development of the carbon-intensive sectors,and environmental regulation and foreign direct investment(FDI)have not yet significantly impacted GTFP.Based on these findings,this paper suggests that the carbon-intensive sectors should expedite their green transitions by focusing on system improvement,technological innovations,energy revolutions,and high-level opening up.展开更多
The study was looking at establishing factors that are affecting the adoption of electronic government services in the Developing Countries for Transport sector amidst the Covid-19 pandemic based on the Unified Theory...The study was looking at establishing factors that are affecting the adoption of electronic government services in the Developing Countries for Transport sector amidst the Covid-19 pandemic based on the Unified Theory of Acceptance and Use of Technology Model (UTAUT). The study first looked at the major challenges faced by the Zambian transport sector in the implementation of e-government services among the citizens. The study then proposed a model through a web-based e-commerce web portal that could be adopted to address the challenges identified in the study. The study was based on all registered motor vehicles. These were from the various transport sectors in Zambia’s capital city, Lusaka. Both qualitative and quantitative data was collected from respondents using a structured questionnaire. The questionnaire was generated based on the UTAUT conceptual model. The response rate was 57% giving 141 questionnaire responses from the four transport providers. The Chi-Square test of independence was used to analyze the data using SPSS software. The results showed that interaction between trust in government and trust in the Internet has a significant effect on the utilisation of e-government services. The test had an observed P-Value of 0.05 against the Chi-Square value of 59.535. The results further showed that e-services control and effort expectancy had a significant impact on the actual utilisation of e-government services.展开更多
This paper uses the SBM-DDF model to measure the green inefficiency of all kinds of industries in Anhui Province under the constraint of carbon emissions from 2006 to 2014.The results show that whether from the perspe...This paper uses the SBM-DDF model to measure the green inefficiency of all kinds of industries in Anhui Province under the constraint of carbon emissions from 2006 to 2014.The results show that whether from the perspective of the overall industries in Anhui Province or from the perspective of separate industry groups,the sources of the green inefticiency are mainly from insufficient industrial output,followed by excessive emissions of CO2.The green inefficiency values of each group(from big to small)are sized down by high-emission industries,medium-emission industries and low-emission industries respectively.During the period of research,the effect of the emission reduction in high-emission industries was not significant,and the potential of reducing the green inefficiency in the medium-emission and low-emission industries by increasing the output was not large.展开更多
文摘The energy sector in Poland is the source of 81% of greenhouse gas（GHG） emissions. Poland,among other European Union countries, occupies a leading position with regard to coal consumption. Polish energy sector actively participates in efforts to reduce GHG emissions to the atmosphere, through a gradual decrease of the share of coal in the fuel mix and development of renewable energy sources. All evidence which completes the knowledge about issues related to GHG emissions is a valuable source of information. The article presents the results of modeling of GHG emissions which are generated by the energy sector in Poland. For a better understanding of the quantitative relationship between total consumption of primary energy and greenhouse gas emission, multiple stepwise regression model was applied. The modeling results of CO2 emissions demonstrate a high relationship（0.97） with the hard coal consumption variable. Adjustment coefficient of the model to actual data is high and equal to 95%. The backward step regression model, in the case of CH4 emission, indicated the presence of hard coal（0.66）, peat and fuel wood（0.34）, solid waste fuels, as well as other sources（- 0.64） as the most important variables. The adjusted coefficient is suitable and equals R2= 0.90. For N2 O emission modeling the obtained coefficient of determination is low and equal to 43%. A significant variable influencing the amount of N2 O emission is the peat and wood fuel consumption.
文摘This paper intends to provide an in-depth and comprehensive analysis of China＇s service sector reform during 1978-2016 and characterize the model of the service sector reform. Due to unique national conditions and development journey, China＇s service sector reform was carried out in the context of China＇s overall reform and opening-up program based on non-industrial motivations with a pragmatic approach to improve both people＇s livelihood and efficiency and address practical problems facing China in various stages of its development, putting aside theoretical controversies. How to further improve the model of China＇s service sector reform that came into shape in such a unique historical context and advance service sector reform is an important yet arduous task.
文摘In this paper, a two\|sector growth model is given. The labor force transfer process from agricultural sector to industrial sector is exogenous determined. By introducing the labor force transferring function, a two\|dimension nonautonomous differential equation is obtained. The results of the model manifest that the labor force transfer delays industrial sector growth and accelerates the agricultural sector growth. It is proved that the solution of the model is asymptotic stable. By the numerical analysis, the economic growth and labor force transfer is presented under the specific parameters.
基金National Science Foundation for Distinguished Young Scholars of China, No.41125005
文摘China has huge differences among its regions in terms of socio-economic development, industrial structure, natural resource endowments, and technological advancement. These differences have created complicated linkages between regions in China. In this study, building upon gravity model and location quotient techniques, we develop a sector-specific model to estimate inter-provincial trade flows, which is the base for making a multi-regional input-output table. In the model, we distinguish sectors with less intra-sector input from those with larger intra-sector input, and assume that the former sectors tend to compete among regions while the latter tend to cooperate among regions. Then we apply this new method of inter-regional trade estimation to three sectors： food and tobacco, metal smelting and proc- essing, and electrical equipment. The results show that selection of bandwidth has a significant impact on the assessment of inter-regional trade. Trade flows are more scattered with the increase of bandwidths. As a result, bandwidth reflects the spatial concentration of geo- graphical activities, which should be distinguishable for different industries. We conclude that the sector-specific spatial model can increase the credibility of estimates of inter-regional trade flows.
基金supported by the National Natural Science Foundation of China(Nos.U1233101,71271113)the Fundamental Research Funds for the Central Universities(No.NS2016062)
文摘Terminal airspace(TMA)is the airspace centering several military and civil aviation airports with complex route structure,limited airspace resources,traffic flow,difficult management and considerable airspace complexity.A scientific and rational sectorization of TMA can optimize airspace resources,and sufficiently utilize the control of human resources to ensure the safety of TMA.The functional sectorization model was established based on the route structure of arriving and departing aircraft as well as controlling requirements.Based on principles of sectorization and topological relations within a network,the arrival and departure sectorization model was established,using tree based ant colony algorithm(ACO)searching.Shanghai TMA was taken as an example to be sectorizaed,and the result showed that this model was superior to traditional ones when arrival and departure routes were separated at dense airport terminal airspace.
文摘In this paper, we subdivide the sample of manufacturing companies listed in two stock exchanges in China from the year 2000 to 2009 into two categories： the firms which adopted the similar financial models and those which did not. Then we use t-test and nonparametric test to explore the differences between the two sub-samples in cash management, assets and liabilities structures, assets turnover ratios, profitability, liquidity and growth rates. The results show that the former has shorter Cash Conversion Cycle （CCC）, quicker assets turnover, higher Debt Ratio （DR）, higher growth rate and thus has better profitability. In addition, the regression analysis results further demonstrate that Return on Invested Capital （ROIC） of similar-financial-model firms are positively related to Net Profit Margin （NPM） （p 〈 0.01）, and negatively to CCC （p 〈 0.01）, Interest Expense Ratio （IER） （p 〈 0.01）, the Ratio of Interest-Bearing Debt to Total Liabilities （IBDR） （p 〈 0.01） and the ratio of Net Receivables to Sales Revenue （NRSR） （p 〈 0.01）. Moreover, negative relationship between ROIC and dummy variable GROUP implies that the former has better profitability than the latter.
文摘The energy sector is the second largest emitter of greenhouse (GHG) gases in Kenya, emitting about 31.2% of GHG emissions in the country. The aim of this study was to model Kenya’s GHG emissions by the energy sector using ARIMA models for forecasting future values. The data used for the study was that of Kenya’s GHG emissions by the energy sector for the period starting from 1970 to 2022 obtained for the International Monetary Fund (IMF) database that was split into training and testing sets using the 80/20 rule for modelling purposes. The best specification for the ARIMA model was identified using Akaike Information Criterion (AIC), root mean squared error (RMSE), mean absolute error (MAE), mean absolute percentage error (MAPE) and mean absolute scaled error (MASE). ARIMA (1, 1, 1) was identified as the best model for modelling Kenya’s GHG emissions and forecasting future values. Using this model, Kenya’s GHG emissions by the energy sector were forecasted to increase to a value of about 43.13 million metric tons of carbon dioxide equivalents by 2030. The study, therefore, recommends that Kenya should accelerate the adjustment of industry structure and improve the efficient use of energy, optimize the energy structure and accelerate development and promotion of energy-efficient products to reduce the emission of GHGs by the country’s energy sector.
基金“This research was funded by Global Green Growth Institute,through his Monitoring,Reporting and Verification National Project in order to highlight Transport sector contribution to National Greenhouses emission”.
文摘Transport sector is cited among the key emitted sector.In Burkina Faso,road transport occupies more than 60%of the emissions of the entire transport sector.However,there is no model equation for greenhouse gases modelling in transport sector.A methodology combining literature review and survey has been adopted to develop the simplified model equation in transport sector.The vehicle type survey allowed the identification of the type of vehicle and the literature review allowed the identification of the key parameters used for greenhouses gases modelling.The results revealed 10 vehicle types for road transport in Burkina Faso such as:Private cars,Public Transport/Buses,Special Vehicle(Ambulances,Fire bus,Funeral vehicles),other vehicle,Motorcycles,Wheeler,Rail,Van,Lorries and Truck Tractor.The keys parameters for greenhouse gases modelling are Fleet availability,Average annual distance travelled,Fuel Economy and Fuel emission factor.For all vehicle type identified simplified model equation was developed to support Burkina Faso,assessing greenhouse gases emission in the sector of transport.This approach could be replicated in other countries in the sub-Saharan Region.
文摘Since reform and opening-up in 1978, changes in China's industrial structure have generally followed the pattern of "Kuznets facts" but still exhibits some unique characteristics, which led us to raise the following three questions regarding China's structural transformation:(1) Why did the share of China's agricultural and manufacturing employment reduce/increase intermittently rather than continuously?(2) Why did the share of China's agricultural employment increase during certain periods? When the share of manufacturing employment reduced, why did the workforce reversely flow into agriculture rather than move to the service sector?(3) Why did growth in the share of China's service sector employment decelerate before reaching its peak? Why did the share of employment in the industrial sector suddenly increase after an abrupt decline? This paper creates a multisector economic growth model that contains non-homothetic preferences and differentiated productivity, and incorporates the "two drivers" therein for a demand-side estimation and analysis. The result shows that China's economic growth model driven by net export and investment is a critical factor for explaining the three questions regarding its structural transformation. This paper believes that only by implementing supply-side structural reforms, reducing the dependence on net export and investment, and achieving sustainable endogenous economic growth will China be able to expedite its industrial restructuring.
基金supported by the Stanford Graduate Fellowship,the Center for Urban Science and Progress at New York Universitythe National Science Foundation under award number CMMI-2053014.The views and opinions expressed in this paper are those of the authors alone.
文摘Interdependencies between critical infrastructures and the economy amplify the effects of damage caused by disasters.The growing interest in impacts beyond physical damage and community resilience has spurred a surge in literature on economic modeling methodologies for estimating indirect economic impacts of disasters and the recovery of economic activity over time.In this review,we present a framework for categorizing modeling approaches that assess indirect economic impacts across natural hazards and anthropogenic disasters such as cyber attacks.We first conduct a comparative analysis of macroeconomic models,focusing on the approaches capturing sectoral interdependencies.These include the Leontief Input-Output(I/O)model,the Inoperability Input-Output Model(IIM),the Dynamic Inoperability Input-Output Model(DIIM),the Adaptive Regional Input-Output(ARIO)model,and the Computable General Equilibrium(CGE)model and its extensions.We evaluate their applicability to disaster scenarios based on input data availability,the compatibility of model assumptions,and output capabilities.We also reveal the functional relationships of input data and output metrics across economic modeling approaches for inter-sectoral impacts.Furthermore,we examine how the damage mechanisms posed by different types of disasters translate into model inputs and impact modeling processes.This synthesis provides guidance for researchers and practitioners in selecting and configuring models based on specific disaster scenarios.It also identifies the gaps in the literature,including the need for a deeper understanding of model performance reliability,key drivers of economic outcomes in different disaster contexts,and the disparities in modeling approach applications across various hazard types.
基金supported by the 2020 National Supercomputing Zhengzhou Center Innovation Ecosystem Construction Technology Project(No.201400210700)Zhengzhou PM2.5 and O3 Collaborative Control and Monitoring Project(No.20220347A).
文摘Recently,the transportation sector in China has gradually become the main source of urban air pollution and primary driver of carbon emissions growth.Considering air pollutants and greenhouse gases come from the same emission sources,it is necessary to establish an updated high-resolution emission inventory for the transportation sector in Central China,themost polluted region in China.The inventory includes on-road mobile,non-roadmobile,oil storage and transportation,and covers 9 types of air pollutants and 3 types of greenhouse gases.Based on the Long-range Energy Alternatives Planning System(LEAP)model,the emissions of pollutants were predicted for the period from2020 to 2035 in different scenarios.Results showed that in 2020,emissions of SO_(2),NO_(x),CO,PM_(10),PM_(2.5),VOCs,NH_(3),BC,OC,CO_(2),CH_(4),and N_(2)O in Henan Province were 27.5,503.2,878.6,20.1,17.4,222.1,21.5,9.4,2.9,92,077.9,6.0,and 10.4 kilotons,respectively.Energy demand and pollutant emissions in Henan Province are simulated under four scenarios(Baseline Scenario(BS),Pollution Abatement Scenario(PA),Green Transportation Scenario(GT),and Reinforcing Low Carbon Scenario(RLC)).The collaborative emission reduction effect is most significant in the RLC scenario,followed by the GT scenario.By 2035,under the RLC scenario,energy consumption and emissions of SO_(2),NO_(x),CO,PM_(10),PM_(2.5),VOCs,NH_(3),CO_(2),CH_(4),and N_(2)O are projected to decrease by 72.0%,30.0%,55.6%,56.0%,38.6%,39.7%,51.5%,66.1%,65.5%,55.4%,and 52.8%,respectively.This study provides fundamental data support for subsequent numerical simulations.
文摘The study constructs a low-carbon path analysis model of China's power sector based on TIMES model and presents a comparative analysis of carbon emissions under Reference,Low-Carbon and Enhanced Low-Carbon scenarios,and the main difference of the three scenarios is manifested by policy selection and policy strength.The conclusions are drawn as follows:(1)The peak of carbon emission in China's power sector will range from 4.0 GtCO2 to 4.8 GtCO2,which implies an increment of 0.5e1.3 billion or 14%e35%from the 2015 levels.(2)Introducing carbon price is an effective way to inhibit coal power and promote non-fossil fuels and Carbon Capture,Utilization and Storage applications(CCUS).The carbon emission reduction effects will gradually increase with carbon price.When the carbon price attains to CN￥150 t1CO2,the CO2 emission can decrease by 36%than that without carbon price.(3)CCUS is one of important contributing factor to reduce CO2 emission in power sector.Generally speaking,the development of non-fossil fuels and energy efficiency improvement are two main drivers for carbon mitigation,but once the carbon price reaches up to CN￥106 t 1CO2,the CCUS will be required to equip with thermal power units and its contribution on carbon emission reduction will remarkably increase.When carbon price increases to CN￥150 t1CO2 in 2050,the application of CCUS will account for 44%of total emission reduction.(4)In the scenario with carbon price of CN￥150 t1CO2,power sector would be decarbonized significantly,and the CO2 intensity will be 0.22 kgCO2(kW h)1,but power sector is far from the goal that achieving net zero emission.In order to realize the long-term low greenhouse gas emission development goal that proposed by the Paris Agreement,more efforts are needed to be put to further reduce the carbon emission reduction of power sector.Based on the above scenario analysis,the study proposes four recommendations on the low-carbon development of China's power sector:(1)improve the energy efficiency proactively and optimize the energy structure of power sector gradually;(2)promote the low-carbon transition of power sector by using market-based mechanism like carbon emission trading scheme to internalize the external cost of carbon emission;(3)give more emphasis on and support to the CCUS application in power sector.
文摘Climate change is expected to have substantial effects on agricultural productivity worldwide. However, these impacts will differ across commodities, locations and time periods. As a result, landowners will see changes in relative returns that are likely to induce modifications in production practices and land allocation. In addition, regional variations in impacts can alter relative competitiveness across countries and lead to adjustments in international trade patterns. Thus in climate change impact studies it is likely useful to account for worldwide productivity effects. In this study, we investigate the implications of considering rest of world climate impacts on projections of the US agricultural exports. We chose to focus on the US because it is one of the largest agricultural exporters. To conduct our analyses, we consider four alternative climate scenarios, both with and without rest of world climate change impacts. Our results show that considering/ignoring rest of world climate impacts causes significant changes in the US production and exports projections. Thus we feel climate change impact studies should account not only for climate impacts in the country of focus but also on productivity in the rest of the world in order to capture effects on commodity markets and trade potential.
基金funded by the Joint Funds of the National Natural Science Foundation of China (61079001)
文摘This paper deals with dynamic airspace sectorization （DAS） problem by an improved genetic algorithm （iGA）. A graph model is first constructed that represents the airspace static structure. Then the DAS problem is formulated as a graph-partitioning problem to balance the sector workload under the premise of ensuring safety. In the iGA, multiple populations and hybrid coding are applied to determine the optimal sector number and airspace sectorization. The sector constraints are well satisfied by the improved genetic operators and protect zones. This method is validated by being applied to the airspace of North China in terms of three indexes, which are sector balancing index, coordination workload index and sector average flight time index. The improvement is obvious, as the sector balancing index is reduced by 16.5 %, the coordination workload index is reduced by 11.2 %, and the sector average flight time index is increased by 11.4 % during the peak-hour traffic.
文摘The electricity needs of populations in Cameroon are increasing and are still very inadequate. Companies, public buildings and households are facing frequent blackout which constrain development and social well-being. Therefore, the present work tried to forecast the electricity demand in the residential sector in Cameroon, in order to contribute significantly to the mastery of electricity consumption and highlight decision-makers in this sector. Six macroeconomics parameters covering the period 1994-2014 are used for these issues. Stationarity tests within gross domestic product, gross domestic product per capita, electricity consumption, population and numbers of subscribers and households respectively;reveal that all the series are I(1). Thus, the VAR (Vector Autoregressive) model has been retained to forecast the electricity demand until 2020. The cusum test and the cusum of squared test attest the stability of that model with a margin of error of 0.02%. Previsions are then more reliable and show that the electric request will skip from 1721 GWh in 2014 to more than 2481 GWh in 2020 approximatively, following a growing yearly rate of 5.36%. In order to reach its emergence, Cameroon ought to speed up its production in the domain of hydroelectric and thermal grid in order to meet the requirements in electric power in short and long term.
文摘The basic aim of this paper is to study and analyze the current level of operational competitiveness of Pakistani Private Sector—Textile Manufacturing Enterprises. The subject research area will be probed on the basis of making cross reference comparison between the Pakistani Private Sector (PPS)—Textile Manufacturing Enterprises (TME) with the global Textile Manufacturing players in global manufacturing strategies databases. The results revealed that the “quality” is the most important competitive priority of the case PPS-TME and it also pointed towards having some competitive advantages in prospector group. However, it will take considerable amount of time for Pakistani Private Sector—Textile Manufacturing Enterprises to regain their previous global recognition and then further improve their operational competitiveness due to the weak and faulty organizational management structure and practices, currently being affected by nation’s political, economic, energy and security situation.
基金part of the project“Research on the Investment Game and Market Improvement of Social Capital in Supporting Poverty Reduction and Development in Ethnic Regions in Western China” (16XMZ094)funded by the National Social Science Fund of China。
文摘This paper uses an SBM-GML index model to assess Green Total Factor Productivity(GTFP)in China's carbon-intensive sectors and conducts an empirical investigation into which factors influence GTFP in these sectors.The GTFP in the carbon-intensive sectors experienced a decline between 2006 and 2011,followed by an upward trend beginning in 2012.Technological progress was the primary driver of GTFP growth,while business size was also a notable contributor.Irrational energy structures negatively influenced the high-quality development of the carbon-intensive sectors,and environmental regulation and foreign direct investment(FDI)have not yet significantly impacted GTFP.Based on these findings,this paper suggests that the carbon-intensive sectors should expedite their green transitions by focusing on system improvement,technological innovations,energy revolutions,and high-level opening up.
文摘The study was looking at establishing factors that are affecting the adoption of electronic government services in the Developing Countries for Transport sector amidst the Covid-19 pandemic based on the Unified Theory of Acceptance and Use of Technology Model (UTAUT). The study first looked at the major challenges faced by the Zambian transport sector in the implementation of e-government services among the citizens. The study then proposed a model through a web-based e-commerce web portal that could be adopted to address the challenges identified in the study. The study was based on all registered motor vehicles. These were from the various transport sectors in Zambia’s capital city, Lusaka. Both qualitative and quantitative data was collected from respondents using a structured questionnaire. The questionnaire was generated based on the UTAUT conceptual model. The response rate was 57% giving 141 questionnaire responses from the four transport providers. The Chi-Square test of independence was used to analyze the data using SPSS software. The results showed that interaction between trust in government and trust in the Internet has a significant effect on the utilisation of e-government services. The test had an observed P-Value of 0.05 against the Chi-Square value of 59.535. The results further showed that e-services control and effort expectancy had a significant impact on the actual utilisation of e-government services.
文摘This paper uses the SBM-DDF model to measure the green inefficiency of all kinds of industries in Anhui Province under the constraint of carbon emissions from 2006 to 2014.The results show that whether from the perspective of the overall industries in Anhui Province or from the perspective of separate industry groups,the sources of the green inefticiency are mainly from insufficient industrial output,followed by excessive emissions of CO2.The green inefficiency values of each group(from big to small)are sized down by high-emission industries,medium-emission industries and low-emission industries respectively.During the period of research,the effect of the emission reduction in high-emission industries was not significant,and the potential of reducing the green inefficiency in the medium-emission and low-emission industries by increasing the output was not large.
