This paper addresses urban sustainability challenges amid global urbanization, emphasizing the need for innova tive approaches aligned with the Sustainable Development Goals. While traditional tools and linear models ...This paper addresses urban sustainability challenges amid global urbanization, emphasizing the need for innova tive approaches aligned with the Sustainable Development Goals. While traditional tools and linear models offer insights, they fall short in presenting a holistic view of complex urban challenges. System dynamics (SD) models that are often utilized to provide holistic, systematic understanding of a research subject, like the urban system, emerge as valuable tools, but data scarcity and theoretical inadequacy pose challenges. The research reviews relevant papers on recent SD model applications in urban sustainability since 2018, categorizing them based on nine key indicators. Among the reviewed papers, data limitations and model assumptions were identified as ma jor challenges in applying SD models to urban sustainability. This led to exploring the transformative potential of big data analytics, a rare approach in this field as identified by this study, to enhance SD models’ empirical foundation. Integrating big data could provide data-driven calibration, potentially improving predictive accuracy and reducing reliance on simplified assumptions. The paper concludes by advocating for new approaches that reduce assumptions and promote real-time applicable models, contributing to a comprehensive understanding of urban sustainability through the synergy of big data and SD models.展开更多
By means of ISM (Interpretative Structural Modeling) and SD (System Dynamics) methods, this paper made a system dynamics model of urbanization and eco-environment coupling in Jiangsu Province according to the implicat...By means of ISM (Interpretative Structural Modeling) and SD (System Dynamics) methods, this paper made a system dynamics model of urbanization and eco-environment coupling in Jiangsu Province according to the implication and PSR (Pressure State Response) framework of urbanization and eco-environment coupling. Moreover, five typical scenarios during 2000-2015 have been simulated and analyzed based on the time serial statistical data during 1990-2003 in Jiangsu, which indicates: firstly, there are significant differences between the results and the scenarios, and the five coupling models all have comparative advantages and drawbacks; secondly, in terms of the characteristics and regional development disparities of Jiangsu and the general rule of world urbanization process, this paper reveals that only when either population urbanization model or social urbanization model to be correspondingly adopted, the sustainable development among population, economy, urbanization and eco-environment can be realized.展开更多
The Chinese government has set ambitious targets to reduce the per unit of GDP by 40% ~45% during 2005 to 2020 and achieve the intensity peaking of carbon emissions of CO2 emissions a- round 2030. The T21 national dev...The Chinese government has set ambitious targets to reduce the per unit of GDP by 40% ~45% during 2005 to 2020 and achieve the intensity peaking of carbon emissions of CO2 emissions a- round 2030. The T21 national development model for China was developed for the purpose of analy- zing the effects of long-term national policies that relate to carbon emissions, loss of farm land, water shortage, energy security, food security, and their contributions to this reduction target. The focus of this paper is on the policies that have substantial impacts on carbon emissions from fossil fuels. Four scenarios are developed with the model to simulate future carbon emissions ： 1 ） the BAU （ busi- ness as usual） scenario, showing the likely results of continuing current policies; 2 ） the TECH （technology） scenario showing the effects of more investment in renewable energy sources and promoting more energy efficient technologies; 3 ） the BEHAVIOR scenario, showing how government tax and price policies, together with public education programs, would instigate behaviour changes towards more sustainable living; and 4 ） the TECH＆BEHA scenario, which shows the results of combining scenarios 2 and 3. The simulation results show that CO2 emissions reduction targets of China are achievable, but also require great effort to put in.展开更多
The economic growth of China has led to increasing growth disparities between regions. Such disparities are uncontrolled and are severely negative symptoms in the process of economic development. On the basis of syste...The economic growth of China has led to increasing growth disparities between regions. Such disparities are uncontrolled and are severely negative symptoms in the process of economic development. On the basis of system dynamics(SD) modeling and the relationship between industrial relocation and regional economic growth, we construct a model of the interrelationship between the two aforementioned phenomena. The model is an effective and creative exploration for examining effects of industrial relocation on Chinese regional economic growth disparities. The SD model is employed in this study to build an inter-regional labor migration SD model, an inter-regional capital migration SD model, an intra-industry SD model, an intra-regional population SD model, and an intra-regional SD model which are based on realities in labor and capital flow from the view of industrial relocation. VENSIM software is utilized to perform a system simulation based on the data of the eastern, middle, and western regions from 2000 to 2010. Results show that industrial relocation gradually narrows the relative disparity in GDP among the three regions. Moreover, the absolute one is enlarged continuously. The absolute and relative disparities in per capita GDP among eastern, middle, and western regions generally exhibit decreasing trends.展开更多
The Manas River Basin in Xinjiang Uygur autonomous region, similar to other arid regions, is facing water constraints which challenge decision-makers as to how to rationally allocate the available water resources to m...The Manas River Basin in Xinjiang Uygur autonomous region, similar to other arid regions, is facing water constraints which challenge decision-makers as to how to rationally allocate the available water resources to meet the demands from industries and natural ecosystems. Policies which integrate the supply and demand are needed to address the water stress issues. An object-oriented system dynamics model was developed to capture the interrelationships between water availability and increasing water demands from the growth of industries, agri- cultural production and the population through modeling the decision-making process of the water exploration ex- plicitly, in which water stress is used as a major indicator. The model is composed of four sectors： 1 ） natural surface and groundwater resources; 2） water demand; 3） the water exploitation process, including the decision to build reservoirs, canals and pumps; 4） water stress to which political and social systems respond through increasing the supply, limiting the growth or improving the water use efficiency. The model was calibrated using data from 1949 to 2009 for population growth, irrigated land area, industry output, perceived water stress, groundwater resources availability and the drying-out process of Manas River; and simulations were carried out from 2010 to 2050 on an annual time step. The comparison of results from calibration and observation showed that the model corresponds to observed behavior, and the simulated values fit the observed data and trends accurately. Sensitivity analysis showed that the model is robust to changes in model parameters related to population growth, land reclamation, pumping capacity and capital contribution to industry development capacity. Six scenarios were designed to inves- tigate the effectiveness of policy options in the area of reservoir relocation, urban water recycling, water demand control and groundwater pumping control. The simulation runs demonstrated that the technical solutions for im- proving water availability and water use efficiency are not sustainable. Acknowledging the carrying capacity of water resources and eliminating a growth-orientated value system are crucial for the sustainability of the Manas River Basin.展开更多
Stage-discharge curves are particularly important in river basin management. For a compound channel, the stage-discharge curve is often difficult to be extrapolated to yield estimates of level for a given frequency of...Stage-discharge curves are particularly important in river basin management. For a compound channel, the stage-discharge curve is often difficult to be extrapolated to yield estimates of level for a given frequency of flow. By analyzing a large number of experimental data from Science and Engineering Research Council Flood Channel Facility (SERC-FCF) and applying system dynamics method, the authors established system dynamics model of conveyance capacity when rivers flow in an overbank mode, spilling onto the adjoining flood plain. The model was applied to a compound channel. And the corresponding simulated results are shown to attain high accurcy.展开更多
This research develops and applies a system dynamics(SD) model for the strategic evaluation of environmental adaptation options for coastal communities. The article defines and estimates asset-based measures for commu...This research develops and applies a system dynamics(SD) model for the strategic evaluation of environmental adaptation options for coastal communities. The article defines and estimates asset-based measures for community vulnerability, resilience, and adaptive capacity with respect to the environmental, economic, social, and cultural pillars of the coastal community under threat. The SD model simulates the annual multidimensional dynamic impacts of severe coastal storms and storm surges on the community pillars under alternative adaptation strategies.The calculation of the quantitative measures provides valuable information for decision makers for evaluating the alternative strategies. The adaptation strategies are designed model results illustrated for the specific context of the coastal community of Charlottetown, Prince Edward Island, Canada. The dynamic trend of the measures and model sensitivity analyses for Charlottetown—facing increased frequency of severe storms, storm surges, and sea-level rise—provide impetus for enhanced community strategic planning for the changing coastal environment.This research is presented as part of the International Community-University Research Alliance C-Change project ‘‘Managing Adaptation to Environmental Change in Coastal Communities: Canada and the Caribbean'' sponsored by the Social Science and Humanities Research Council of Canada and the International Development Resource Centre.展开更多
China is currently the largest emitter of carbon dioxide globally.The nation,vulnerable to the imminent challenges of climate change and greenhouse gas emissions,is determined to reduce emissions.Thus,by adopting a sy...China is currently the largest emitter of carbon dioxide globally.The nation,vulnerable to the imminent challenges of climate change and greenhouse gas emissions,is determined to reduce emissions.Thus,by adopting a systemstheory approach,this study is aimed at examining how the agricultural lands,output values,production activities,and populations,as well as the economic factors,influence carbon emissions in Sichuan Province.To offer insights into the long-term agricultural carbon emission(ACE)trajectories,a system dynamics model is used to predict the emission trends from 2023 to 2040.The findings indicate the following:①policy regulation exerts influence on the ACE in the province.As per the simulation results,regulating the gross domestic product growth of the primary industry at 2.5%,5%,and 10%will only increase the carbon emissions by 0.24%,0.25%,and 0.53%,respectively,by 2040,indicating that effective policy regulations can decouple economic growth from substantial increases in emissions,thereby underscoring their pivotal role in emission control.②Regulating the agricultural-economy growth rate and policies can effectively reduce ACEs in the province.③While single policies exert limited influence,combining multiple measures significantly boosts carbon reduction.For example,comprehensive strategies,including reduced pesticide use and marginal farmland conversion,can lower agricultural land carbon emissions by 3.48%,5.30%,and 7.47%(by 2035)and 1.67%,2.76%,and 3.65%(by 2040).Overall,these results emphasize the effectiveness of coordinated policies,alongside market control and land-use adjustments,in advancing low-carbon agricultural development.展开更多
Elm(Ulmus pumila L.)is the dominant tree species in the sparse elm woodland,the original vegetation in the Horqin Sandy Land.The effects of changes in precipitation on U.pumila trees have not been fully studied.We det...Elm(Ulmus pumila L.)is the dominant tree species in the sparse elm woodland,the original vegetation in the Horqin Sandy Land.The effects of changes in precipitation on U.pumila trees have not been fully studied.We determined a dynamic model by considering the five stages in the U.pumila life cycle,i.e.seed,seedling,and juvenile,mature and over-mature tree stages.The effects of changes in precipitation on population density and age structure were then evaluated.Population density,after averaging all study developmental morphology stages,ranged from 16.67 individuals/m2 to 25.01 individuals/m2 under a mean annual precipitation(MAP)of 80%to 120%,respectively.This suggests that population density could increase as MAP also increased.The proportion of seedlings,and juvenile,mature and over-mature trees were 95.23%,4.58%,0.19%and 0.01%,respectively,under all precipitation levels.This indicates that precipitation had little effects on the developmental stages of the studied U.pumila populations in the Horqin Sandy Land.Additional water supply might be provided in addition to the natural rainfall that occurs in the region,for contributing to maintain U.pumila population density in the Horqin Sandy Land.展开更多
Based on the logical causal relationship and taking Liaoning Province, China, which is the Chinese traditional industrial base and is in the stage of accelerated urbanisation, as a case study, this study builds the ＇...Based on the logical causal relationship and taking Liaoning Province, China, which is the Chinese traditional industrial base and is in the stage of accelerated urbanisation, as a case study, this study builds the ＇Urbanisation-Energy Consumption-COn Emissions System Dynamics （UEC-SD）＇ model using a system dynamics method. The UEC-SD model is applied to analyse the effect of the ar- banisation process on the regional energy structure and CO2 emissions, followed by simulation of future production and living energy consumption structure as well as the evolutionary trend of CO2 emissions of three urbanisation scenarios （low speed, intermediate speed and high speed） under the assumed boundary conditions in urban and rural areas of Liaoning Province, China. The results show that the urbanisation process can alter production and the living energy consumption structure and thereby change regional CO2 emissions. An increase in the urbanisation rate in case area will lead to regional COz emissions rising in the short term, but when the urbanisation rate approaches 80%, CO2 emissions will reach a peak value and then decrease. Comparison of different urbanisation rates showed that pro- duction and living energy consumption exhibit different directions of change and rules in urban and rural areas. The effect of urbanisa- tion on CO2 emissions and energy structure is not direct, and urbanisation can increase the differences in energy and CO2 emissions between urban and rural areas caused by the industrial structure, technical level and other factors.展开更多
Due to long-term human activity interference,the Hainan Tropical Rainforest National Park(HTRNP)of China has experienced ecological problems such as habitat fragmentation and biodiversity loss,and with the expanding s...Due to long-term human activity interference,the Hainan Tropical Rainforest National Park(HTRNP)of China has experienced ecological problems such as habitat fragmentation and biodiversity loss,and with the expanding scope and intensity of human activity impact,the regional ecological security is facing serious challenges.A scientific assessment of the interrelationship between human activity intensity and habitat quality in the HTRNP is a prerequisite for achieving effective management of ecological disturbances caused by human activities and can also provide scientific strategies for the sustainable development of the region.Based on the land use change data in 2000,2010,and 2020,the spatial and temporal variations and the relationship between habitat quality(HQ)and human activity intensity(HAI)in the HTRNP were explored using the integrated valuation of ecosystem services and trade-offs(InVEST)model.System dynamics and land use simulation models were also combined to conduct multi-scenario simulations of their relationships.The results showed that during 2000–2020,the habitat quality of the HTRNP improved,the intensity of human activities decreased each year,and there was a negative correlation between the two.Second,the system dynamic model could be well coupled with the land use simulation model by combining socio-economic and natural factors.The simulation scenarios of the coupling model showed that the harmonious development(HD)scenario is effective in curbing the increasing trend of human activity intensity and decreasing trend of habitat quality,with a weaker trade-off between the two compared with the baseline development(BD)and investment priority oriented(IPO)scenarios.To maintain the authenticity and integrity of the HTRNP,effective measures such as ecological corridor construction,ecological restoration,and the implementation of ecological compensation policies need to be strengthened.展开更多
Abstract Cities based on coal resources have increasingly important social and economic roles in China. Their strategies for sustainable development, however, urgently need to be improved, which represents a huge chal...Abstract Cities based on coal resources have increasingly important social and economic roles in China. Their strategies for sustainable development, however, urgently need to be improved, which represents a huge challenge. Most observers believe that the continued progress of these cities relies on the optimization of scientific adaptive management in which social, economic, and ecological factors are incorporated. A systems perspective that combines policies, management priorities, and long-term policy impacts needs to be applied. To date, however, such an approach has not been adopted, which means it is difficult to implement adaptive management at the regional scale. In this study, we used various situations to develop a multiple adaptive scenario system dynamics model. We then simulated a range of policy scenarios, with Ordos in the Inner Mongolia Autonomous Region as a case study. Simulation results showed that the current strategy is not sustainable and predicted that the system would exceed the environmental capacity, with risks of resource exhaustion and urban decline in 2025-2035. Five critical policy variables, including the urban population carrying capacity, rates of water consumption and water recycling, and expansion of urban land cover, were identified during sensitivity analysis. We developed and compared six socio-economic scenarios. The urban area, represented by the urban population density, seemed to transition through five different stages, namely natural growth, rapid growth, stable oscillation, fading, and rebalancing. Our scenarios suggested that different policies had different roles through each stage. The water use efficiency management policy had a comprehensive far-reaching influence on the system behavior; land urbanization management functions dominated at the start, and population capacity management was a major control in the mid-term. Our results showed that the water recycling policy and the urban population carrying capacity were extremely important, and both should be reinforced and evaluated by the local governments.展开更多
Coal production capacity regulation is a complex system involving economic growth,structural optimization,high-efficiency mining,and environmental protection.Based on its driving factors,this paper forms four regulati...Coal production capacity regulation is a complex system involving economic growth,structural optimization,high-efficiency mining,and environmental protection.Based on its driving factors,this paper forms four regulation modes representing different control orientations,establishes a system dynamics model,and predicts the regulation effects of single-factor and combined control mode.The result shows:(1) Except for the mechanization degree and recovery rate,the other nine individual production capacity control policies are all conducive to reducing coal production capacity and restraining the excessive growth of coal production capacity.(2) The effect of combined regulation mode on slowing down the growth of coal demand,regulating the excessive growth of coal production capacity and new capacity investment are obviously better than that of single policy.(3) The combined control modes have obvious differences in the suppression effect on coal production capacity:transformational development mode > technology-driven mode > structural optimization mode > efficiency improvement mode.Therefore,in the process of achieving optimal regulation of coal production capacity,attention should be paid to the preferential use of transformational development and technology-driven mode.At the same time,the comprehensive use of regulation and control methods should also be considered to improve the regulation effect and the regulation efficiency of coal production capacity.展开更多
China’s policy on cropland protection is a fundamental agricultural policy,which supports the state’s sustainable development goals of eradicating hunger,achieving food security,improving nutrition and promoting sus...China’s policy on cropland protection is a fundamental agricultural policy,which supports the state’s sustainable development goals of eradicating hunger,achieving food security,improving nutrition and promoting sustainable agriculture.We combined the SD and PLUS models to construct an integrated framework for simulating future areas of cropland and their spatial distribution.We simulated the spatial and temporal changes in cropland in Guangxi Autonomous Region under different scenarios in 2030,2040 and 2050.The results showed that the simulation error for historical cropland areas using the SD model was≤3%.The PLUS model results for the spatial distribution of cropland in Guangxi in 2020 was 0.92 for overall accuracy(OA),0.77 for Kappa,and 0.33 for the figure of merit(FOM).Thus,the integrated model was suitable for simulating cropland in Guangxi under different future scenarios.Analyses of the landscape index,standard deviation ellipse and hot spots were performed to examine the spatial and temporal distribution characteristics of Guangxi’s cropland under different future scenarios in more detail.They indicated that the area of cropland in Guangxi under different future scenarios gradually decreased,with the SSP245 scenario showing the greatest decrease in the area of cropland.Cropland in Guangxi showed a westward shift under different future scenarios,which was most rapid under the SSP245 scenario.cropland remained fragmented from 2000 to 2020,with fragmentation intensifying under different future scenarios,while cropland shifted to western rocky,desertified and poverty-affected areas.In sum,the results show that the SD-PLUS integrated model can predict the change trend of cropland in Guangxi under different future scenarios,which facilitates optimisation of the spatial allocation and planning of cropland and provides key data for implementing future cropland protection policies in Guangxi.展开更多
The Microgravity Active vibration Isolation System(MAIS),which was onboard China’s first cargo-spacecraft Tianzhou-1 launched on April 20,2017,aims to provide high-level microgravity at an order of 10^(-5)–10^(-6)g ...The Microgravity Active vibration Isolation System(MAIS),which was onboard China’s first cargo-spacecraft Tianzhou-1 launched on April 20,2017,aims to provide high-level microgravity at an order of 10^(-5)–10^(-6)g for specific scientific experiments.MAIS is mainly composed of a stator and a floater,and payloads are mounted on the floater.Sensing relative motion with respect to the stator fixed on the spacecraft,the floater is isolated from vibration on the stator via control forces and torques generated by electromagnetic actuators.This isolation results in a high-level microgravity environment.Before MAIS was launched into space,its control performance had been simulated on computers and tested by air-bearing platform levitation and aircraft parabolic flight.This article first presents an overview of the MAIS’s hardware system,particularly system structure,measurement sensors,and control actuators.Its system dynamics,state estimation,and control laws are then discussed,followed by the results of computer simulation and engineering tests,including the test of the six-degree-of-freedom motion by aircraft parabolic flight.Simulation and test results verify the accuracy of the control strategy design,effectiveness of the control algorithms,and performance of the entire control system,paving the way for operation of MAIS in space.This article also presents the steps recommended for the control performance simulation and tests of MAIS-like devices.These devices are expected to be used on China’s Space Station for various scientific experiments that require a high-level microgravity environment.展开更多
In order to find some effective management policy by the feedback archetypes analysis. To the minimum archetypes generating problem of a complex system, we transform the rate variable fundamental in-tree model of SD t...In order to find some effective management policy by the feedback archetypes analysis. To the minimum archetypes generating problem of a complex system, we transform the rate variable fundamental in-tree model of SD to a diagonal-0 branch-vector matrix using the method combining graph theory and algebra. We create the branch vector matrix formula to generate minimum archetypes of the network flow diagram. We solve the problem of how to generate the minimum archetypes of the complex system archetype generating method, and create a SD model of a human resource management in an organization using this new method. We prove that there are 16 new positive feedback loops and 17 negative feedback loops of 2 to 6 order of the HR management that is based on the incitements of performance levels. At the same time, these policies restrain the performance of the organization because of the increasing of cost. By analyze the growth limited structure model, we find the policy of increasing the performance of both the employee and the organization.展开更多
Due to a lack of resources,rural communities often face challenges when planning catastrophic events.This project involved applying systems thinking and model-based systems engineering to develop a proof-of-concept,mu...Due to a lack of resources,rural communities often face challenges when planning catastrophic events.This project involved applying systems thinking and model-based systems engineering to develop a proof-of-concept,multi-method computer simulation and then determining whether the simulation could be used to assess the efficacy of disaster planning approaches on health outcomes in rural communities,as a function of primary healthcare.The project focus was a rural or non-urban healthcare system experiencing a natural hazard.Both system dynamics and discrete event models were incorporated to represent subsystem operations,crucial disaster responses,as well as three key response systems:public health,emergency management,and healthcare.The subsystem models included several components:policies/procedures,communications,resources,exercises/drills/training,healthcare space and staff,and the flow of affected people into and through the system.The combined simulation can serve as a first step to a more comprehensive approach to helping rural communities achieve more efficient and effective healthcare planning for disaster responses.展开更多
A global enterprise must continuously improve the efficiency of logistic operations between supply chain collaborators. Integrating logistic services, resources, and necessary information flows in the supply chain to ...A global enterprise must continuously improve the efficiency of logistic operations between supply chain collaborators. Integrating logistic services, resources, and necessary information flows in the supply chain to ensure efficiency and efficacy is critically important to these companies. Global logistic service companies face challenges from their clients to provide logistic services that are cost effective, accurate, and seamlessly integrate material, information and cash flows. In this research, an improved framework for one-stop logistic services is systematically designed, analyzed, and evaluated. The one-stop logistic service framework, defmed in four models, is developed to provide enterprises with integrated and comprehensive services within the global supply chain context. The levels of service importance are assessed using a four categories questionnaire. This research provides a case study of the implementation of one-stop logistic services in the distribution industry and demonstrates the framework operating under different demand conditions. Finally, system dynamics causal evaluation is used to evaluate the advantages of the logistic service framework.展开更多
基金sponsored by the U.S.Department of Housing and Urban Development(Grant No.NJLTS0027-22)The opinions expressed in this study are the authors alone,and do not represent the U.S.Depart-ment of HUD’s opinions.
文摘This paper addresses urban sustainability challenges amid global urbanization, emphasizing the need for innova tive approaches aligned with the Sustainable Development Goals. While traditional tools and linear models offer insights, they fall short in presenting a holistic view of complex urban challenges. System dynamics (SD) models that are often utilized to provide holistic, systematic understanding of a research subject, like the urban system, emerge as valuable tools, but data scarcity and theoretical inadequacy pose challenges. The research reviews relevant papers on recent SD model applications in urban sustainability since 2018, categorizing them based on nine key indicators. Among the reviewed papers, data limitations and model assumptions were identified as ma jor challenges in applying SD models to urban sustainability. This led to exploring the transformative potential of big data analytics, a rare approach in this field as identified by this study, to enhance SD models’ empirical foundation. Integrating big data could provide data-driven calibration, potentially improving predictive accuracy and reducing reliance on simplified assumptions. The paper concludes by advocating for new approaches that reduce assumptions and promote real-time applicable models, contributing to a comprehensive understanding of urban sustainability through the synergy of big data and SD models.
文摘By means of ISM (Interpretative Structural Modeling) and SD (System Dynamics) methods, this paper made a system dynamics model of urbanization and eco-environment coupling in Jiangsu Province according to the implication and PSR (Pressure State Response) framework of urbanization and eco-environment coupling. Moreover, five typical scenarios during 2000-2015 have been simulated and analyzed based on the time serial statistical data during 1990-2003 in Jiangsu, which indicates: firstly, there are significant differences between the results and the scenarios, and the five coupling models all have comparative advantages and drawbacks; secondly, in terms of the characteristics and regional development disparities of Jiangsu and the general rule of world urbanization process, this paper reveals that only when either population urbanization model or social urbanization model to be correspondingly adopted, the sustainable development among population, economy, urbanization and eco-environment can be realized.
基金Supported by the National Science&Technology Pillar Program(No.2012BAC20B09)
文摘The Chinese government has set ambitious targets to reduce the per unit of GDP by 40% ~45% during 2005 to 2020 and achieve the intensity peaking of carbon emissions of CO2 emissions a- round 2030. The T21 national development model for China was developed for the purpose of analy- zing the effects of long-term national policies that relate to carbon emissions, loss of farm land, water shortage, energy security, food security, and their contributions to this reduction target. The focus of this paper is on the policies that have substantial impacts on carbon emissions from fossil fuels. Four scenarios are developed with the model to simulate future carbon emissions ： 1 ） the BAU （ busi- ness as usual） scenario, showing the likely results of continuing current policies; 2 ） the TECH （technology） scenario showing the effects of more investment in renewable energy sources and promoting more energy efficient technologies; 3 ） the BEHAVIOR scenario, showing how government tax and price policies, together with public education programs, would instigate behaviour changes towards more sustainable living; and 4 ） the TECH＆BEHA scenario, which shows the results of combining scenarios 2 and 3. The simulation results show that CO2 emissions reduction targets of China are achievable, but also require great effort to put in.
基金Under the auspices of National Natural Science Foundation of China(No.41171099)National Key Basic Research Program of China(No.2012CB955802)National Social Science Foundation of China(No.10ZD&022)
文摘The economic growth of China has led to increasing growth disparities between regions. Such disparities are uncontrolled and are severely negative symptoms in the process of economic development. On the basis of system dynamics(SD) modeling and the relationship between industrial relocation and regional economic growth, we construct a model of the interrelationship between the two aforementioned phenomena. The model is an effective and creative exploration for examining effects of industrial relocation on Chinese regional economic growth disparities. The SD model is employed in this study to build an inter-regional labor migration SD model, an inter-regional capital migration SD model, an intra-industry SD model, an intra-regional population SD model, and an intra-regional SD model which are based on realities in labor and capital flow from the view of industrial relocation. VENSIM software is utilized to perform a system simulation based on the data of the eastern, middle, and western regions from 2000 to 2010. Results show that industrial relocation gradually narrows the relative disparity in GDP among the three regions. Moreover, the absolute one is enlarged continuously. The absolute and relative disparities in per capita GDP among eastern, middle, and western regions generally exhibit decreasing trends.
基金supported by the National Basic Research Program of China (2010CB951004)a project of Xinjiang Key Lab of Water Cycle and Utilization in Arid Zone,Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences (XJYS0907-2009-02)
文摘The Manas River Basin in Xinjiang Uygur autonomous region, similar to other arid regions, is facing water constraints which challenge decision-makers as to how to rationally allocate the available water resources to meet the demands from industries and natural ecosystems. Policies which integrate the supply and demand are needed to address the water stress issues. An object-oriented system dynamics model was developed to capture the interrelationships between water availability and increasing water demands from the growth of industries, agri- cultural production and the population through modeling the decision-making process of the water exploration ex- plicitly, in which water stress is used as a major indicator. The model is composed of four sectors： 1 ） natural surface and groundwater resources; 2） water demand; 3） the water exploitation process, including the decision to build reservoirs, canals and pumps; 4） water stress to which political and social systems respond through increasing the supply, limiting the growth or improving the water use efficiency. The model was calibrated using data from 1949 to 2009 for population growth, irrigated land area, industry output, perceived water stress, groundwater resources availability and the drying-out process of Manas River; and simulations were carried out from 2010 to 2050 on an annual time step. The comparison of results from calibration and observation showed that the model corresponds to observed behavior, and the simulated values fit the observed data and trends accurately. Sensitivity analysis showed that the model is robust to changes in model parameters related to population growth, land reclamation, pumping capacity and capital contribution to industry development capacity. Six scenarios were designed to inves- tigate the effectiveness of policy options in the area of reservoir relocation, urban water recycling, water demand control and groundwater pumping control. The simulation runs demonstrated that the technical solutions for im- proving water availability and water use efficiency are not sustainable. Acknowledging the carrying capacity of water resources and eliminating a growth-orientated value system are crucial for the sustainability of the Manas River Basin.
文摘Stage-discharge curves are particularly important in river basin management. For a compound channel, the stage-discharge curve is often difficult to be extrapolated to yield estimates of level for a given frequency of flow. By analyzing a large number of experimental data from Science and Engineering Research Council Flood Channel Facility (SERC-FCF) and applying system dynamics method, the authors established system dynamics model of conveyance capacity when rivers flow in an overbank mode, spilling onto the adjoining flood plain. The model was applied to a compound channel. And the corresponding simulated results are shown to attain high accurcy.
基金the community-based University of Ottawa EnRiCH project (http://www.enrichproject.ca/), led by Dr. Tracey O’Sullivan of the Interdisciplinary Faculty of Health Sciences, University of Ottawathe ‘‘C-Change’’ International Community-University Research Alliance (ICURA) (http://www.coastalchange.ca) funded by the Social Sciences and Humanities Research Council (SSHRC) of Canadathe International Development Research Centre (IDRC)
文摘This research develops and applies a system dynamics(SD) model for the strategic evaluation of environmental adaptation options for coastal communities. The article defines and estimates asset-based measures for community vulnerability, resilience, and adaptive capacity with respect to the environmental, economic, social, and cultural pillars of the coastal community under threat. The SD model simulates the annual multidimensional dynamic impacts of severe coastal storms and storm surges on the community pillars under alternative adaptation strategies.The calculation of the quantitative measures provides valuable information for decision makers for evaluating the alternative strategies. The adaptation strategies are designed model results illustrated for the specific context of the coastal community of Charlottetown, Prince Edward Island, Canada. The dynamic trend of the measures and model sensitivity analyses for Charlottetown—facing increased frequency of severe storms, storm surges, and sea-level rise—provide impetus for enhanced community strategic planning for the changing coastal environment.This research is presented as part of the International Community-University Research Alliance C-Change project ‘‘Managing Adaptation to Environmental Change in Coastal Communities: Canada and the Caribbean'' sponsored by the Social Science and Humanities Research Council of Canada and the International Development Resource Centre.
文摘China is currently the largest emitter of carbon dioxide globally.The nation,vulnerable to the imminent challenges of climate change and greenhouse gas emissions,is determined to reduce emissions.Thus,by adopting a systemstheory approach,this study is aimed at examining how the agricultural lands,output values,production activities,and populations,as well as the economic factors,influence carbon emissions in Sichuan Province.To offer insights into the long-term agricultural carbon emission(ACE)trajectories,a system dynamics model is used to predict the emission trends from 2023 to 2040.The findings indicate the following:①policy regulation exerts influence on the ACE in the province.As per the simulation results,regulating the gross domestic product growth of the primary industry at 2.5%,5%,and 10%will only increase the carbon emissions by 0.24%,0.25%,and 0.53%,respectively,by 2040,indicating that effective policy regulations can decouple economic growth from substantial increases in emissions,thereby underscoring their pivotal role in emission control.②Regulating the agricultural-economy growth rate and policies can effectively reduce ACEs in the province.③While single policies exert limited influence,combining multiple measures significantly boosts carbon reduction.For example,comprehensive strategies,including reduced pesticide use and marginal farmland conversion,can lower agricultural land carbon emissions by 3.48%,5.30%,and 7.47%(by 2035)and 1.67%,2.76%,and 3.65%(by 2040).Overall,these results emphasize the effectiveness of coordinated policies,alongside market control and land-use adjustments,in advancing low-carbon agricultural development.
基金supported by the National Nature Science Foundation of China(41870709)the Scientific Research Program of the Education Department of Liaoning province(LYB201613)China Postdoctoral Science Foundation funded project(2017M611251).
文摘Elm(Ulmus pumila L.)is the dominant tree species in the sparse elm woodland,the original vegetation in the Horqin Sandy Land.The effects of changes in precipitation on U.pumila trees have not been fully studied.We determined a dynamic model by considering the five stages in the U.pumila life cycle,i.e.seed,seedling,and juvenile,mature and over-mature tree stages.The effects of changes in precipitation on population density and age structure were then evaluated.Population density,after averaging all study developmental morphology stages,ranged from 16.67 individuals/m2 to 25.01 individuals/m2 under a mean annual precipitation(MAP)of 80%to 120%,respectively.This suggests that population density could increase as MAP also increased.The proportion of seedlings,and juvenile,mature and over-mature trees were 95.23%,4.58%,0.19%and 0.01%,respectively,under all precipitation levels.This indicates that precipitation had little effects on the developmental stages of the studied U.pumila populations in the Horqin Sandy Land.Additional water supply might be provided in addition to the natural rainfall that occurs in the region,for contributing to maintain U.pumila population density in the Horqin Sandy Land.
基金Under the auspices of National Natural Science Foundation of China(No.41301637,41101117,41271186)Key Program of National Natural Science Foundation of China(No.71133003)
文摘Based on the logical causal relationship and taking Liaoning Province, China, which is the Chinese traditional industrial base and is in the stage of accelerated urbanisation, as a case study, this study builds the ＇Urbanisation-Energy Consumption-COn Emissions System Dynamics （UEC-SD）＇ model using a system dynamics method. The UEC-SD model is applied to analyse the effect of the ar- banisation process on the regional energy structure and CO2 emissions, followed by simulation of future production and living energy consumption structure as well as the evolutionary trend of CO2 emissions of three urbanisation scenarios （low speed, intermediate speed and high speed） under the assumed boundary conditions in urban and rural areas of Liaoning Province, China. The results show that the urbanisation process can alter production and the living energy consumption structure and thereby change regional CO2 emissions. An increase in the urbanisation rate in case area will lead to regional COz emissions rising in the short term, but when the urbanisation rate approaches 80%, CO2 emissions will reach a peak value and then decrease. Comparison of different urbanisation rates showed that pro- duction and living energy consumption exhibit different directions of change and rules in urban and rural areas. The effect of urbanisa- tion on CO2 emissions and energy structure is not direct, and urbanisation can increase the differences in energy and CO2 emissions between urban and rural areas caused by the industrial structure, technical level and other factors.
基金Under the auspices of the National Social Science Found of China(No.21XGL019)Hainan Provincial Natural Science Foundation of China(No.421RC1034)Professor/Doctor Research Foundation of Huizhou University(No.2022JB080)。
文摘Due to long-term human activity interference,the Hainan Tropical Rainforest National Park(HTRNP)of China has experienced ecological problems such as habitat fragmentation and biodiversity loss,and with the expanding scope and intensity of human activity impact,the regional ecological security is facing serious challenges.A scientific assessment of the interrelationship between human activity intensity and habitat quality in the HTRNP is a prerequisite for achieving effective management of ecological disturbances caused by human activities and can also provide scientific strategies for the sustainable development of the region.Based on the land use change data in 2000,2010,and 2020,the spatial and temporal variations and the relationship between habitat quality(HQ)and human activity intensity(HAI)in the HTRNP were explored using the integrated valuation of ecosystem services and trade-offs(InVEST)model.System dynamics and land use simulation models were also combined to conduct multi-scenario simulations of their relationships.The results showed that during 2000–2020,the habitat quality of the HTRNP improved,the intensity of human activities decreased each year,and there was a negative correlation between the two.Second,the system dynamic model could be well coupled with the land use simulation model by combining socio-economic and natural factors.The simulation scenarios of the coupling model showed that the harmonious development(HD)scenario is effective in curbing the increasing trend of human activity intensity and decreasing trend of habitat quality,with a weaker trade-off between the two compared with the baseline development(BD)and investment priority oriented(IPO)scenarios.To maintain the authenticity and integrity of the HTRNP,effective measures such as ecological corridor construction,ecological restoration,and the implementation of ecological compensation policies need to be strengthened.
基金supported by the National Natural Science Foundation of China(Grant Nos.41590845&41601096)the China Postdoctoral Science Foundation(Grant No.2015M581160)
文摘Abstract Cities based on coal resources have increasingly important social and economic roles in China. Their strategies for sustainable development, however, urgently need to be improved, which represents a huge challenge. Most observers believe that the continued progress of these cities relies on the optimization of scientific adaptive management in which social, economic, and ecological factors are incorporated. A systems perspective that combines policies, management priorities, and long-term policy impacts needs to be applied. To date, however, such an approach has not been adopted, which means it is difficult to implement adaptive management at the regional scale. In this study, we used various situations to develop a multiple adaptive scenario system dynamics model. We then simulated a range of policy scenarios, with Ordos in the Inner Mongolia Autonomous Region as a case study. Simulation results showed that the current strategy is not sustainable and predicted that the system would exceed the environmental capacity, with risks of resource exhaustion and urban decline in 2025-2035. Five critical policy variables, including the urban population carrying capacity, rates of water consumption and water recycling, and expansion of urban land cover, were identified during sensitivity analysis. We developed and compared six socio-economic scenarios. The urban area, represented by the urban population density, seemed to transition through five different stages, namely natural growth, rapid growth, stable oscillation, fading, and rebalancing. Our scenarios suggested that different policies had different roles through each stage. The water use efficiency management policy had a comprehensive far-reaching influence on the system behavior; land urbanization management functions dominated at the start, and population capacity management was a major control in the mid-term. Our results showed that the water recycling policy and the urban population carrying capacity were extremely important, and both should be reinforced and evaluated by the local governments.
基金support provided by National Social Science:China’s coal industry excess capacity and policy selection issues under the background of the new normal (Nos.16BJY054)。
文摘Coal production capacity regulation is a complex system involving economic growth,structural optimization,high-efficiency mining,and environmental protection.Based on its driving factors,this paper forms four regulation modes representing different control orientations,establishes a system dynamics model,and predicts the regulation effects of single-factor and combined control mode.The result shows:(1) Except for the mechanization degree and recovery rate,the other nine individual production capacity control policies are all conducive to reducing coal production capacity and restraining the excessive growth of coal production capacity.(2) The effect of combined regulation mode on slowing down the growth of coal demand,regulating the excessive growth of coal production capacity and new capacity investment are obviously better than that of single policy.(3) The combined control modes have obvious differences in the suppression effect on coal production capacity:transformational development mode > technology-driven mode > structural optimization mode > efficiency improvement mode.Therefore,in the process of achieving optimal regulation of coal production capacity,attention should be paid to the preferential use of transformational development and technology-driven mode.At the same time,the comprehensive use of regulation and control methods should also be considered to improve the regulation effect and the regulation efficiency of coal production capacity.
文摘China’s policy on cropland protection is a fundamental agricultural policy,which supports the state’s sustainable development goals of eradicating hunger,achieving food security,improving nutrition and promoting sustainable agriculture.We combined the SD and PLUS models to construct an integrated framework for simulating future areas of cropland and their spatial distribution.We simulated the spatial and temporal changes in cropland in Guangxi Autonomous Region under different scenarios in 2030,2040 and 2050.The results showed that the simulation error for historical cropland areas using the SD model was≤3%.The PLUS model results for the spatial distribution of cropland in Guangxi in 2020 was 0.92 for overall accuracy(OA),0.77 for Kappa,and 0.33 for the figure of merit(FOM).Thus,the integrated model was suitable for simulating cropland in Guangxi under different future scenarios.Analyses of the landscape index,standard deviation ellipse and hot spots were performed to examine the spatial and temporal distribution characteristics of Guangxi’s cropland under different future scenarios in more detail.They indicated that the area of cropland in Guangxi under different future scenarios gradually decreased,with the SSP245 scenario showing the greatest decrease in the area of cropland.Cropland in Guangxi showed a westward shift under different future scenarios,which was most rapid under the SSP245 scenario.cropland remained fragmented from 2000 to 2020,with fragmentation intensifying under different future scenarios,while cropland shifted to western rocky,desertified and poverty-affected areas.In sum,the results show that the SD-PLUS integrated model can predict the change trend of cropland in Guangxi under different future scenarios,which facilitates optimisation of the spatial allocation and planning of cropland and provides key data for implementing future cropland protection policies in Guangxi.
基金The authors gratefully acknowledge DLR for providing us the opportunity to attend the 27th parabolic flight campaign and Novespace for the support for the test of MAIS by the Airbus A310 ZERO-GThe authors would also like to thank Weijia Ren,Xiaoru Sang,Shimeng Lv,Peng Yang,Yu-e Gao,Lingcai Song,Mengxi Yu,Boqi Kang,Yanlin Zhou,and Anping Wang,who have contributed significantly to the MAIS project.
文摘The Microgravity Active vibration Isolation System(MAIS),which was onboard China’s first cargo-spacecraft Tianzhou-1 launched on April 20,2017,aims to provide high-level microgravity at an order of 10^(-5)–10^(-6)g for specific scientific experiments.MAIS is mainly composed of a stator and a floater,and payloads are mounted on the floater.Sensing relative motion with respect to the stator fixed on the spacecraft,the floater is isolated from vibration on the stator via control forces and torques generated by electromagnetic actuators.This isolation results in a high-level microgravity environment.Before MAIS was launched into space,its control performance had been simulated on computers and tested by air-bearing platform levitation and aircraft parabolic flight.This article first presents an overview of the MAIS’s hardware system,particularly system structure,measurement sensors,and control actuators.Its system dynamics,state estimation,and control laws are then discussed,followed by the results of computer simulation and engineering tests,including the test of the six-degree-of-freedom motion by aircraft parabolic flight.Simulation and test results verify the accuracy of the control strategy design,effectiveness of the control algorithms,and performance of the entire control system,paving the way for operation of MAIS in space.This article also presents the steps recommended for the control performance simulation and tests of MAIS-like devices.These devices are expected to be used on China’s Space Station for various scientific experiments that require a high-level microgravity environment.
文摘In order to find some effective management policy by the feedback archetypes analysis. To the minimum archetypes generating problem of a complex system, we transform the rate variable fundamental in-tree model of SD to a diagonal-0 branch-vector matrix using the method combining graph theory and algebra. We create the branch vector matrix formula to generate minimum archetypes of the network flow diagram. We solve the problem of how to generate the minimum archetypes of the complex system archetype generating method, and create a SD model of a human resource management in an organization using this new method. We prove that there are 16 new positive feedback loops and 17 negative feedback loops of 2 to 6 order of the HR management that is based on the incitements of performance levels. At the same time, these policies restrain the performance of the organization because of the increasing of cost. By analyze the growth limited structure model, we find the policy of increasing the performance of both the employee and the organization.
基金funding support from Oak Ridge Associated Universities(ORAU)Foundations for this research。
文摘Due to a lack of resources,rural communities often face challenges when planning catastrophic events.This project involved applying systems thinking and model-based systems engineering to develop a proof-of-concept,multi-method computer simulation and then determining whether the simulation could be used to assess the efficacy of disaster planning approaches on health outcomes in rural communities,as a function of primary healthcare.The project focus was a rural or non-urban healthcare system experiencing a natural hazard.Both system dynamics and discrete event models were incorporated to represent subsystem operations,crucial disaster responses,as well as three key response systems:public health,emergency management,and healthcare.The subsystem models included several components:policies/procedures,communications,resources,exercises/drills/training,healthcare space and staff,and the flow of affected people into and through the system.The combined simulation can serve as a first step to a more comprehensive approach to helping rural communities achieve more efficient and effective healthcare planning for disaster responses.
基金This work was supported by the International Research Center of Big Data for Sustainable Development Goals,the National Natural Science Foundation of China(42271422 and 41930648)the Open Fund of Key Laboratory of Urban Land Resources Monitoring and Simulation,Ministry of Natural Resources(KF-2020-05-025).
文摘A global enterprise must continuously improve the efficiency of logistic operations between supply chain collaborators. Integrating logistic services, resources, and necessary information flows in the supply chain to ensure efficiency and efficacy is critically important to these companies. Global logistic service companies face challenges from their clients to provide logistic services that are cost effective, accurate, and seamlessly integrate material, information and cash flows. In this research, an improved framework for one-stop logistic services is systematically designed, analyzed, and evaluated. The one-stop logistic service framework, defmed in four models, is developed to provide enterprises with integrated and comprehensive services within the global supply chain context. The levels of service importance are assessed using a four categories questionnaire. This research provides a case study of the implementation of one-stop logistic services in the distribution industry and demonstrates the framework operating under different demand conditions. Finally, system dynamics causal evaluation is used to evaluate the advantages of the logistic service framework.
