Urban traffic congestion is a significant challenge that contributes to high-density environments in urban areas,adversely impacting the living conditions of urban residents.The concept of urban renewal introduces new...Urban traffic congestion is a significant challenge that contributes to high-density environments in urban areas,adversely impacting the living conditions of urban residents.The concept of urban renewal introduces new requirements and challenges pertaining to urban transportation issues.To mitigate urban traffic congestion,enhance the greening rate of the city,and improve the urban environment,the concept of developing urban aerial ecological corridors is proposed.An analysis of the current state of various urban aerial corridors in different cities indicates that aerial ecological corridors effectively enhance connectivity and accessibility between different spaces,representing a significant strategy for addressing the issue of urban traffic congestion.Aerial ecological corridors have the potential to enhance the vertical space within urban environments,increase the greening rate of cities,and promote the physical and mental health of urban residents.Additionally,these corridors can improve the connectivity of habitat patches and address the developmental needs of biodiversity.Consequently,they serve as a crucial foundation for guiding the future transformation of urban development towards a healthier and greener direction.展开更多
Recent years have witnessed rapid and widespread economic growth in regions involved in China’s Belt and Road Initiative(BRI),mainly due to the construction of six economic corridors.This paper aims to quantify the l...Recent years have witnessed rapid and widespread economic growth in regions involved in China’s Belt and Road Initiative(BRI),mainly due to the construction of six economic corridors.This paper aims to quantify the levels of six economic corridors according to the socioeconomic development levels in the BRI regions.Here,a gridded socioeconomic development index was first created,and a dividing line was drawn to reveal the distribution characteristics of socioeconomic development in the BRI regions.A classification method was then applied to identify local development levels.Finally,we created an economic corridor development index(ECDI)to evaluate the progress of six economic corridors.The results reveal spatial heterogeneity within the socioeconomic groups of BRI regions,which can be roughly divided into offshore(or Part A,50.54%)and inland(or Part B,49.46%)areas.Although both parts comprise roughly the same area,over 95%of the population is located in offshore regions.The China–Mongolia–Russia Economic Corridor has the highest development index due to a stable political environment and long-running cooperation.The China–Pakistan Economic Corridor suffers from the lowest ECDI but with strong development potential.Our methods can provide critical reference and practice for the future evaluation of the level of regional development.The results of this study can offer policymakers some insight into reducing socioeconomic inequality in the BRI regions.展开更多
With the accelerated urbanization,human activities pose serious threats to species because of fragmentation.Planning conservation corridors between habitats could improve species mobility in order to address the human...With the accelerated urbanization,human activities pose serious threats to species because of fragmentation.Planning conservation corridors between habitats could improve species mobility in order to address the human disturbance.However,there are a limited number of studies that focus on assessing the effect of human activities on species movement in mountain areas as well as how to integrate different conservation models relating to conservation corridors identification.In our study,we modified the resistance model and took land use data as input parameters to quantify the impacts of human activities in mountain areas.Meanwhile,different conservation planning models,including Circuit model and Least Cost Path(LCP)algorithm,were integrated.Moreover,our approach was applied to identify giant panda corridors in Miarro nature reserve,Caopo nature reserve,and Wolong nature reserve.The results suggested that the impacts of human activities were limited in valley regions due to topography by resistance model.Secondly,Circuit model demonstrated that the conservation corridors for giant panda could not be identified between the Miarro and the Caopo nature reserves.Additionally,more detailed corridors between habitats were planned by the LCP algorithm.Furthermore,we also identified bottlenecks for migration in each corridor,indicating that human activities’interference was the primary cause.Our approach not only could connect habitats for conservation in mountain areas but also found out that the corridor could not be identified between habitats.展开更多
Sustainability is popularly defined as meeting the needs of the present generation without compromising the ability of future generations to meet their own needs. Social, economic and environmental parameters are most...Sustainability is popularly defined as meeting the needs of the present generation without compromising the ability of future generations to meet their own needs. Social, economic and environmental parameters are most commonly accepted as the three pillars of sustainability. In this paper, various sustainability indicators have been identified during the construction stage for elevated transportation corridors and thereafter classified under various categories. Using fuzzy VIKOR technique, sustainability evaluation of transportation corridors is made on two selected project sites of two different government organizations using various identified sustainability indicators, i.e., a 3.2-km long elevated road project under construction from Vikaspuri to Meerabagh in West Delhi by PWD （Public Works Department） and the metro rail elevated corridor （part） from Punjabi Bagh to Mayapuri as a part of Phase 3, Line 7 by DMRC （Delhi Metro Rail Corporation）. The study is made at both sites in the midst of the construction period and it is identified that during the construction stage, the sustainability of these transportation corridors is just not limited to three pillars, but in actuality, it is much beyond that. From the study, it is inferred that the metro rail elevated corridor is a more sustainable corridor, in the context of the identified sustainability indicators.展开更多
Corridors are special patches with narrow and long shape, and often have the functions as transportation,protection, resources and aesthetics. Corridors in the study area can be classilied into 8 types, with a total l...Corridors are special patches with narrow and long shape, and often have the functions as transportation,protection, resources and aesthetics. Corridors in the study area can be classilied into 8 types, with a total length of 5167. 2 km, and conidor density of 1. 25 km/km2. The conidore are mainly composed of irrigation and drainag canals,the total length of which is 2794 km,about 54. 1% of all the corridors. The conidors have segmented the landscape, and changed the original situation of the natural landscapes. The types of conidors are clooely related to the landscape types they are distributed in. Canals are maily distributed in the wetland landscapes, while roads are mainly in the built-up area. Dikes are always along rivers or coastlines. The conidors are most densely distributed wherever human activity occurs most bouendy, such as in the artifical wedlands of paddy fields.展开更多
The rapid development of multimodal transportation system prompts travellers to choose multiple transportation modes, such as private vehicles or taxi, transit(subways or buses), or park-and-ride combinations for urba...The rapid development of multimodal transportation system prompts travellers to choose multiple transportation modes, such as private vehicles or taxi, transit(subways or buses), or park-and-ride combinations for urban trips. Traffic corridor is a major scenario that supports travellers to commute from suburban residential areas to central working areas. Studying their modal choice behaviour is receiving more and more interests. On one hand, it will guide the travellers to rationally choose their most economic and beneficial mode for urban trips. On the other hand, it will help traffic operators to make more appropriate policies to enhance the share of public transit in order to alleviate the traffic congestion and produce more economic and social benefits. To analyze the travel modal choice, a generalized cost model for three typical modes is first established to evaluate each different travel alternative. Then, random utility theory(RUT) and decision field theory(DFT) are introduced to describe the decision-making process how travellers make their mode choices. Further, some important factors that may influence the modal choice behaviour are discussed as well. To test the feasibility of the proposed model, a field test in Beijing was conducted to collect the real-time data and estimate the model parameters. The improvements in the test results and analysis show new advances in the development of travel mode choice on multimodal transportation networks.展开更多
The problem of designing integration traffic strategies for traffic corridors with the use of ramp metering, speed limit, and route guidance is considered in this paper. As an improvement to the previous work, the pre...The problem of designing integration traffic strategies for traffic corridors with the use of ramp metering, speed limit, and route guidance is considered in this paper. As an improvement to the previous work, the presented approach has the following five features： 1） modeling traffic flow to analyze traffic characteristics under the influence of variable speed limit, on-ramp metering and guidance information; 2） building a hierarchy model to realize the integration design of traffic control and route guidance in traffic corridors; 3） devising a multi-class analytical dynamic traffic assignment （DTA） model for traffic corridors, where not only the route choice process will be different for each user-class, but also the traffic flow operations are user-class specific because the travel time characteristic for each user-class is considered; 4） predicting route choice probabilities adaptively with real-time traffic conditions and route choice behaviors corresponding to variant users, rather than assuming as pre-determined; and 5） suggesting a numerical solution algorithm of the hierarchy model presented in this paper based on the modified algorithm of iterative optimization assignment （IOA）. Preliminary numerical test demonstrates the potential of the developed model and algorithm for integration corridor control.展开更多
Introduction The Caspian-Black Sea-Mediterranean Corridor["CORRIDOR"]encompasses the Eurasian intercontinental basins of the Caspian,Black,Marmara,Aegean,and Eastern Mediterranean(Levantine)seas with their c...Introduction The Caspian-Black Sea-Mediterranean Corridor["CORRIDOR"]encompasses the Eurasian intercontinental basins of the Caspian,Black,Marmara,Aegean,and Eastern Mediterranean(Levantine)seas with their connecting straits and coasts.Periodic connection/isolation of the basins during the Quaternary predetermined their specific environmental conditions and particular hydrologic regimes,and thus,the area,and especially the Ponto-Caspian,represents a“natural laboratory”to study the responses of semi-isolated and isolated basins to climate changes.展开更多
The landlocked countries are the one without access to the sea and can be assimilate as countries around the world with a disadvantage of geography situation location. Chad and the Central African Republic are two of ...The landlocked countries are the one without access to the sea and can be assimilate as countries around the world with a disadvantage of geography situation location. Chad and the Central African Republic are two of the 40 landlocked countries around the world that transport 80% of their goods by road and rail, and as much as almost more than 50% of their passengers through a transit country with a transit transport system which is crucial for their trade and exchanges. The study aims to introduce the importance to have a good and efficiency transport network infrastructure in Central Africa to facilitate the trade for the landlocked countries of Central Africa (Chad and the Central African Republic), member of CEMAC trade area and proposes some measures that can be adopt</span><span style="font-family:"">ed</span><span style="font-family:""> to improve their conditions and ameliorate the trade for those countries.展开更多
In this paper,an adaptive Unmanned Ground Vehicle swarm(UGVS)control for crossing corridors or gaps with self-organized formation is proposed to overcome the limitations of obstacle scenes.In traditional methods,obsta...In this paper,an adaptive Unmanned Ground Vehicle swarm(UGVS)control for crossing corridors or gaps with self-organized formation is proposed to overcome the limitations of obstacle scenes.In traditional methods,obstacles are typically arranged in a regular and simplistic manner,often relying on global information for path planning,which makes it difficult to deal with more complex scenes.To tackle this problem,the authors propose a new control strategy to achieve efficient tracking and obstacle avoidance of UGVS in corridors or gaps environments.Firstly,a constraint model that considers the performance of tracking,obstacle avoidance,and formation maintenance is constructed,which is more suitable for obstacle scenes of complex corridors or gaps.Secondly,a new control framework based on the barrier Lyapunov function(BLF)is proposed to achieve tracking and obstacle avoidance of UGVS through constraint control.Meanwhile,a control strategy of UGVS for crossing corridors or gaps is designed,which avoids pre-training for specific obstacle scenes and cumbersome path planning for each individual.At last,the stability analysis is provided by the designed Lyapunov function.Simulation results of three different scenes verify the effectiveness of the proposed method.展开更多
This paper investigates the mechanisms and effects of international transport corridors on the growth of China's environmental goods exports.Using bilateral data between Chinese provinces and their trading partner...This paper investigates the mechanisms and effects of international transport corridors on the growth of China's environmental goods exports.Using bilateral data between Chinese provinces and their trading partners,this study treats the opening of the China-Europe Railway Express(CRE)as a quasi-experiment and employs a staggered difference-in-differences method for empirical testing.The results show that the opening of the CRE has promoted the growth of China's environmental goods exports.This growth was driven by mechanisms that increased demand in the international market,diversified the export of environmental goods,stimulated environmental innovation,and enhanced China's capacity to supply environmental goods globally.Significant heterogeneity was observed in the trade of environmental goods due to differences in product types,exporting provinces,and importing countries.The findings suggest that the international transport corridors can generate mutual benefits in the trade of environmental goods.展开更多
Based on a comprehensive analysis of the domestic academic research on corridors,this paper argues that distinct disciplines define corridors differently,with varying research purposes.Professor Fei Xiaotong advocated...Based on a comprehensive analysis of the domestic academic research on corridors,this paper argues that distinct disciplines define corridors differently,with varying research purposes.Professor Fei Xiaotong advocated that the fundamental purpose of corridor research is to expound on the formation and development of the Chinese nation.Furthermore,the paper provides a detailed analysis of the six major corridors referenced in ethnological research and proposes the use of the concept of"mortise-and-tenon joint"to reinterpret the significant role of these corridors in the formation and development of both the territory of China as a multi-ethnic state and the Chinese nation.展开更多
Ventilation corridors in cities can decrease air pollution and alleviate heat island problems but there remains a need to fully assess their effectiveness.Few urban managers have been able to take city-scale approache...Ventilation corridors in cities can decrease air pollution and alleviate heat island problems but there remains a need to fully assess their effectiveness.Few urban managers have been able to take city-scale approaches to the construction of urban ventilation corridors.This study aimed to introduced the Ventilation Corridor Planning(VCP)model,which is a multi-criteria evaluation method combined with a geographical information system(GIS)to determine where the ventilated environment is most appropriate.Specifically,the VCP model took Bozhou,China as the research object and contained two scales,including mesoscale and local scale.In mesoscale scale,we got three outputs to build urban ventilation corridors,including 1)background wind environment,2)ventilation potential,3)heat island intensity.In local scale,we used traditional computational fluid dynamics(CFD)model to verify the impact of VCP criteria.The results revealed that compared with the traditional CFD model,the proposed VCP model has advantages in establishing a comprehensive evaluation standard.In addition,the application of VCP model in macro and micro also enhances the efficiency of ventilation corridor construction.Overall,this study introduced a effective modeling method to urban ventilation corridors planning,and provide a way to study the urban climate.展开更多
Aims Riparian corridors play vital roles in the maintenance of biodiversity.Nonetheless,plant species diversity and vegetation coverage in riparian corridors are seriously threatened by increasing pressure owing to li...Aims Riparian corridors play vital roles in the maintenance of biodiversity.Nonetheless,plant species diversity and vegetation coverage in riparian corridors are seriously threatened by increasing pressure owing to livestock consumption and anthropogenic disturbance;even the stability of river courses has been threatened.The establishment of enclosures is a widely used strategy to restore degraded grassland ecosystems,but its impact on degraded herbaceous riparian vegetation and soil properties remains unclear.The aim of this study was to evaluate whether species composition,richness,diversity,and soil properties can be recovered by the enclosure.Methods Twenty long-term monitoring sample plots were set in the Liaohe main stream river,Liaohe main stream river was enclosed for grazing and farmland exclusion in 2012.The height,coverage and individual numbers of plant were recorded for species richness and diversity evaluation from 2012 to 2017;soil nutrients were measured for comparative analysis in 2012 and 2017.We examined the effects of the establishment of enclosures on plant species diversity and soil properties from 2012 to 2017 in the riparian corridors of the Liaohe River system in China.Important Findings Plant species richness and diversity significantly increased from 2012 to 2017.The dominance of Asteraceae plants increased,while the abundance of Gramineae plants decreased over time.The difference in abundance increased each year since enclosure was implemented in 2012.The concentrations of phosphorus and potassium in the soil significantly decreased as a result of the combined effects of vegetation restoration and prohibition of farming practices following the establishment of enclosures.There was also a lag time related to the response of soil organic matter to the establishment of enclosures.In conclusion,our study provides new evidence regarding the response of species diversity,species composition and soil properties following riparian vegetation restoration efforts through enclosure development.展开更多
Generating dynamically feasible trajectory for fixed-wing Unmanned Aerial Vehicles(UAVs)in dense obstacle environments remains computationally intractable.This paper proposes a Safe Flight Corridor constrained Sequent...Generating dynamically feasible trajectory for fixed-wing Unmanned Aerial Vehicles(UAVs)in dense obstacle environments remains computationally intractable.This paper proposes a Safe Flight Corridor constrained Sequential Convex Programming(SFC-SCP)to improve the computation efficiency and reliability of trajectory generation.SFC-SCP combines the front-end convex polyhedron SFC construction and back-end SCP-based trajectory optimization.A Sparse A^(*)Search(SAS)driven SFC construction method is designed to efficiently generate polyhedron SFC according to the geometric relation among obstacles and collision-free waypoints.Via transforming the nonconvex obstacle-avoidance constraints to linear inequality constraints,SFC can mitigate infeasibility of trajectory planning and reduce computation complexity.Then,SCP casts the nonlinear trajectory optimization subject to SFC into convex programming subproblems to decrease the problem complexity.In addition,a convex optimizer based on interior point method is customized,where the search direction is calculated via successive elimination to further improve efficiency.Simulation experiments on dense obstacle scenarios show that SFC-SCP can generate dynamically feasible safe trajectory rapidly.Comparative studies with state-of-the-art SCP-based methods demonstrate the efficiency and reliability merits of SFC-SCP.Besides,the customized convex optimizer outperforms off-the-shelf optimizers in terms of computation time.展开更多
Land use/cover change(LUCC)constitutes the spatial and temporal patterns of ecological security,and the construction of ecological networks is an effective way to ensure ecological security.Exploring the spatial and t...Land use/cover change(LUCC)constitutes the spatial and temporal patterns of ecological security,and the construction of ecological networks is an effective way to ensure ecological security.Exploring the spatial and temporal change characteristics of ecological network and analyzing the integrated relationship between LUCC and ecological security are crucial for ensuring regional ecological security.Gansu is one of the provinces with fragile ecological environment in China,and rapid changes in land use patterns in recent decades have threatened ecological security.Therefore,taking Gansu Province as the study area,this study simulated its land use pattern in 2050 using patch-generating land use simulation(PLUS)model based on the LUCC trend from 2000 to 2020 and integrated the LUCC into morphological spatial pattern analysis(MSPA)to identify ecological sources and extract the ecological corridors to construct ecological network using circuit theory.The results revealed that,according to the prediction results in 2050,the areas of cultivated land,forest land,grassland,water body,construction land,and unused land would be 63,447.52,39,510.80,148,115.18,4605.21,8368.89,and 161,752.40 km^(2),respectively.The number of ecological sources in Gansu Province would increase to 80,with a total area of 99,927.18 km^(2).The number of ecological corridors would increase to 191,with an estimated total length of 6120.66 km.Both ecological sources and ecological corridors showed a sparse distribution in the northwest and dense distribution in the southeast of the province at the spatial scale.The number of ecological pinch points would reach 312 and the total area would expect to increase to 842.84 km^(2),with the most pronounced increase in the Longdong region.Compared with 2020,the number and area of ecological barriers in 2050 would decrease significantly by 63 and 370.71 km^(2),respectively.In general,based on the prediction results,the connectivity of ecological network of Gansu Province would increase in 2050.To achieve the predicted ecological network in 2050,emphasis should be placed on the protection of cultivated land and ecological land,the establishment of ecological sources in desert areas,the reinforcement of the protection for existing ecological sources,and the construction of ecological corridors to enhance the stability of ecological network.This study provides valuable theoretical support and references for the future construction of ecological networks and regional land resource management decision-making.展开更多
Scientifically constructing an ecological security pattern(ESP)is an important spatial analysis approach to improve ecological functions in arid areas and achieve sustainable development.However,previous research meth...Scientifically constructing an ecological security pattern(ESP)is an important spatial analysis approach to improve ecological functions in arid areas and achieve sustainable development.However,previous research methods ignored the complex trade-offs between ecosystem services in the process of constructing ESP.Taking the mainstream of the Tarim River Basin(MTRB),China as the study area,this study set seven risk scenarios by applying Ordered Weighted Averaging(OWA)model to trade-off the importance of the four ecosystem services adopted by this study(water conservation,carbon storage,habitat quality,and biodiversity conservation),thereby identifying priority protection areas for ecosystem services.And then,this study identified ecological sources by integrating ecosystem service importance with eco-environmental sensitivity.Using circuit theory,the ecological corridors and nodes were extracted to construct the ESP.The results revealed significant spatial heterogeneity in the four ecosystem services across the study area,primarily driven by hydrological gradients and human activity intensity.The ESP of the MTRB included 34 ecological sources with a total area of 1471.38 km^(2),66 ecological corridors with a length of about 1597.45 km,11 ecological pinch points,and 13 ecological barrier points distributed on the ecological corridors.The spatial differentiation of the ESP was obvious,with the upper and middle reaches of the MTRB having a large number of ecological sources and exhibiting higher clustering of ecological corridors compared with the lower reaches.The upper and middle reaches require ecological protection to sustain the existing ecosystem,while the lower reaches need to carry out ecological restoration measures including desertification control.Overall,this study makes up for the shortcomings of constructing ESP simply by spatial superposition of ecosystem service functions and can effectively improve the robustness and stability of ESP construction.展开更多
Global climate warming has placed immense pressure on the ecological environment worldwide,and the ecological issues affecting the quality of the living environment have garnered widespread attention.In this context,t...Global climate warming has placed immense pressure on the ecological environment worldwide,and the ecological issues affecting the quality of the living environment have garnered widespread attention.In this context,the question of“how to effectively optimize regional ecological network patterns”has become one of the critical issues that urban and rural planning and ecological geography need to address.This study takes Huzhou,Zhejiang Province,China,as the research area,and uses a combination of landscape type transition matrices and landscape pattern indices to analyze the evolution characteristics of green space landscape patterns from 2017 to 2022.Through geographical detectors and GBDT(Gradient Boosting Decision Tree)algorithms,the study explores the driving factors behind the changes in green space landscape patterns.Based on MSPA(Morphological Spatial Pattern Analysis),key ecological sources in Huzhou are extracted.Using a combination of resistance surfaces and gravity models,ecological corridors and networks are constructed.The study also provides suggestions for the evaluation and optimization of ecological network patterns.The aim is to summarize generalizable patterns of green space landscape evolution and methods for constructing and optimizing regional ecological corridor networks,offering insights and references for the improvement of the living environment and the construction of ecological civilization.展开更多
The Inner Asian Mountain Corridor(IAMC)acted as a crossroads of trans-Eurasian exchange since approximately 6000 cal.yr BP.The history of the introduction and utilization of crops and livestock in the area has been in...The Inner Asian Mountain Corridor(IAMC)acted as a crossroads of trans-Eurasian exchange since approximately 6000 cal.yr BP.The history of the introduction and utilization of crops and livestock in the area has been intensively discussed,while geographical-temporal variations of human activities and subsistence strategies remain unclear.Here we report new zooarchaeological data and radiocarbon dates from the Naba Cemeteries,revealing herbivorous livestock were predominant animal resource during both the Bronze and Early Iron Ages,and sheep/goat and horse were paramount sacrificial animals in these two periods,respectively.In tandem with published radiocarbon dates,zooarchaeological and archaeobotanical data from IAMC's prehistoric sites,we detect humans mainly engaged in hunting-gathering games in the IAMC during 8000-5000 cal.yr BP.During 5000-4000 cal.yr BP,the territory of agro-pastoral groups evidently expanded in the IAMC with a hotspot in the Altai Region,and wheat and barley were introduced into the area.In the following two millennia,herding became an economic mainstay,and cultivations of crops were ubiquitous in the IAMC's oases.We argue that prehistoric human activities in the IAMC were mainly affected by agro-pastoral expansions associated with exchanges across the Eurasia,which was likely promoted by climate change.展开更多
基金Sponsored by Research Team Project of Anhui Xinhua University(kytd202202)Anhui Provincial Undergraduate Innovation Training Program(S202212216146,S202212216133,S202212216138,AH202112216114)Key Project of Anhui Provincial Higher Education Scientific Research Project(Natural Science)(2022AH051861,2024AH050601).
文摘Urban traffic congestion is a significant challenge that contributes to high-density environments in urban areas,adversely impacting the living conditions of urban residents.The concept of urban renewal introduces new requirements and challenges pertaining to urban transportation issues.To mitigate urban traffic congestion,enhance the greening rate of the city,and improve the urban environment,the concept of developing urban aerial ecological corridors is proposed.An analysis of the current state of various urban aerial corridors in different cities indicates that aerial ecological corridors effectively enhance connectivity and accessibility between different spaces,representing a significant strategy for addressing the issue of urban traffic congestion.Aerial ecological corridors have the potential to enhance the vertical space within urban environments,increase the greening rate of cities,and promote the physical and mental health of urban residents.Additionally,these corridors can improve the connectivity of habitat patches and address the developmental needs of biodiversity.Consequently,they serve as a crucial foundation for guiding the future transformation of urban development towards a healthier and greener direction.
基金The Strategic Priority Research Program of the Chinese Academy of Sciences,No.XDA20010203The Second Tibetan Plateau Scientific Expedition and Research Program,No.2019QZKK1006+1 种基金National Natural Science Foundation of China,No.42130508The Chinese Academy of Sciences,No.ZDRW-XH-2021-3。
文摘Recent years have witnessed rapid and widespread economic growth in regions involved in China’s Belt and Road Initiative(BRI),mainly due to the construction of six economic corridors.This paper aims to quantify the levels of six economic corridors according to the socioeconomic development levels in the BRI regions.Here,a gridded socioeconomic development index was first created,and a dividing line was drawn to reveal the distribution characteristics of socioeconomic development in the BRI regions.A classification method was then applied to identify local development levels.Finally,we created an economic corridor development index(ECDI)to evaluate the progress of six economic corridors.The results reveal spatial heterogeneity within the socioeconomic groups of BRI regions,which can be roughly divided into offshore(or Part A,50.54%)and inland(or Part B,49.46%)areas.Although both parts comprise roughly the same area,over 95%of the population is located in offshore regions.The China–Mongolia–Russia Economic Corridor has the highest development index due to a stable political environment and long-running cooperation.The China–Pakistan Economic Corridor suffers from the lowest ECDI but with strong development potential.Our methods can provide critical reference and practice for the future evaluation of the level of regional development.The results of this study can offer policymakers some insight into reducing socioeconomic inequality in the BRI regions.
基金funded by National Nature Science Foundation of China(Grant No.41701114)the West Light Foundation of The Chinese Academy of Sciences(Grant No.Y7R280080)the Research on Conservation and Breeding of Plant Diversity in Giant Panda National Park(Grant No.2018SZDZX0035)
文摘With the accelerated urbanization,human activities pose serious threats to species because of fragmentation.Planning conservation corridors between habitats could improve species mobility in order to address the human disturbance.However,there are a limited number of studies that focus on assessing the effect of human activities on species movement in mountain areas as well as how to integrate different conservation models relating to conservation corridors identification.In our study,we modified the resistance model and took land use data as input parameters to quantify the impacts of human activities in mountain areas.Meanwhile,different conservation planning models,including Circuit model and Least Cost Path(LCP)algorithm,were integrated.Moreover,our approach was applied to identify giant panda corridors in Miarro nature reserve,Caopo nature reserve,and Wolong nature reserve.The results suggested that the impacts of human activities were limited in valley regions due to topography by resistance model.Secondly,Circuit model demonstrated that the conservation corridors for giant panda could not be identified between the Miarro and the Caopo nature reserves.Additionally,more detailed corridors between habitats were planned by the LCP algorithm.Furthermore,we also identified bottlenecks for migration in each corridor,indicating that human activities’interference was the primary cause.Our approach not only could connect habitats for conservation in mountain areas but also found out that the corridor could not be identified between habitats.
文摘Sustainability is popularly defined as meeting the needs of the present generation without compromising the ability of future generations to meet their own needs. Social, economic and environmental parameters are most commonly accepted as the three pillars of sustainability. In this paper, various sustainability indicators have been identified during the construction stage for elevated transportation corridors and thereafter classified under various categories. Using fuzzy VIKOR technique, sustainability evaluation of transportation corridors is made on two selected project sites of two different government organizations using various identified sustainability indicators, i.e., a 3.2-km long elevated road project under construction from Vikaspuri to Meerabagh in West Delhi by PWD （Public Works Department） and the metro rail elevated corridor （part） from Punjabi Bagh to Mayapuri as a part of Phase 3, Line 7 by DMRC （Delhi Metro Rail Corporation）. The study is made at both sites in the midst of the construction period and it is identified that during the construction stage, the sustainability of these transportation corridors is just not limited to three pillars, but in actuality, it is much beyond that. From the study, it is inferred that the metro rail elevated corridor is a more sustainable corridor, in the context of the identified sustainability indicators.
文摘Corridors are special patches with narrow and long shape, and often have the functions as transportation,protection, resources and aesthetics. Corridors in the study area can be classilied into 8 types, with a total length of 5167. 2 km, and conidor density of 1. 25 km/km2. The conidore are mainly composed of irrigation and drainag canals,the total length of which is 2794 km,about 54. 1% of all the corridors. The conidors have segmented the landscape, and changed the original situation of the natural landscapes. The types of conidors are clooely related to the landscape types they are distributed in. Canals are maily distributed in the wetland landscapes, while roads are mainly in the built-up area. Dikes are always along rivers or coastlines. The conidors are most densely distributed wherever human activity occurs most bouendy, such as in the artifical wedlands of paddy fields.
基金Project(2012CB725405)supported in part by National Basic Research Program of ChinaProject(2014BAG03B01)supported by the National Science and Technology Support Program,China+1 种基金Project(71301083)supported by the National Natural Science Foundation of ChinaProject(20131089307)supported by the Project Supported by Tsinghua University,China
文摘The rapid development of multimodal transportation system prompts travellers to choose multiple transportation modes, such as private vehicles or taxi, transit(subways or buses), or park-and-ride combinations for urban trips. Traffic corridor is a major scenario that supports travellers to commute from suburban residential areas to central working areas. Studying their modal choice behaviour is receiving more and more interests. On one hand, it will guide the travellers to rationally choose their most economic and beneficial mode for urban trips. On the other hand, it will help traffic operators to make more appropriate policies to enhance the share of public transit in order to alleviate the traffic congestion and produce more economic and social benefits. To analyze the travel modal choice, a generalized cost model for three typical modes is first established to evaluate each different travel alternative. Then, random utility theory(RUT) and decision field theory(DFT) are introduced to describe the decision-making process how travellers make their mode choices. Further, some important factors that may influence the modal choice behaviour are discussed as well. To test the feasibility of the proposed model, a field test in Beijing was conducted to collect the real-time data and estimate the model parameters. The improvements in the test results and analysis show new advances in the development of travel mode choice on multimodal transportation networks.
基金supported by the National Natural Science Foundation of China (No.50808025)the Ministry of Communications of China Application Foundation (No.2006319815080)+1 种基金the Key Project of Hunan Education Department (No.08A003)the Project of Hunan Science and Technology Department (No.2008GK3114)
文摘The problem of designing integration traffic strategies for traffic corridors with the use of ramp metering, speed limit, and route guidance is considered in this paper. As an improvement to the previous work, the presented approach has the following five features： 1） modeling traffic flow to analyze traffic characteristics under the influence of variable speed limit, on-ramp metering and guidance information; 2） building a hierarchy model to realize the integration design of traffic control and route guidance in traffic corridors; 3） devising a multi-class analytical dynamic traffic assignment （DTA） model for traffic corridors, where not only the route choice process will be different for each user-class, but also the traffic flow operations are user-class specific because the travel time characteristic for each user-class is considered; 4） predicting route choice probabilities adaptively with real-time traffic conditions and route choice behaviors corresponding to variant users, rather than assuming as pre-determined; and 5） suggesting a numerical solution algorithm of the hierarchy model presented in this paper based on the modified algorithm of iterative optimization assignment （IOA）. Preliminary numerical test demonstrates the potential of the developed model and algorithm for integration corridor control.
文摘Introduction The Caspian-Black Sea-Mediterranean Corridor["CORRIDOR"]encompasses the Eurasian intercontinental basins of the Caspian,Black,Marmara,Aegean,and Eastern Mediterranean(Levantine)seas with their connecting straits and coasts.Periodic connection/isolation of the basins during the Quaternary predetermined their specific environmental conditions and particular hydrologic regimes,and thus,the area,and especially the Ponto-Caspian,represents a“natural laboratory”to study the responses of semi-isolated and isolated basins to climate changes.
文摘The landlocked countries are the one without access to the sea and can be assimilate as countries around the world with a disadvantage of geography situation location. Chad and the Central African Republic are two of the 40 landlocked countries around the world that transport 80% of their goods by road and rail, and as much as almost more than 50% of their passengers through a transit country with a transit transport system which is crucial for their trade and exchanges. The study aims to introduce the importance to have a good and efficiency transport network infrastructure in Central Africa to facilitate the trade for the landlocked countries of Central Africa (Chad and the Central African Republic), member of CEMAC trade area and proposes some measures that can be adopt</span><span style="font-family:"">ed</span><span style="font-family:""> to improve their conditions and ameliorate the trade for those countries.
基金supported by the National Natural Science Foundation of China under Grant Nos.62373302and 62333009。
文摘In this paper,an adaptive Unmanned Ground Vehicle swarm(UGVS)control for crossing corridors or gaps with self-organized formation is proposed to overcome the limitations of obstacle scenes.In traditional methods,obstacles are typically arranged in a regular and simplistic manner,often relying on global information for path planning,which makes it difficult to deal with more complex scenes.To tackle this problem,the authors propose a new control strategy to achieve efficient tracking and obstacle avoidance of UGVS in corridors or gaps environments.Firstly,a constraint model that considers the performance of tracking,obstacle avoidance,and formation maintenance is constructed,which is more suitable for obstacle scenes of complex corridors or gaps.Secondly,a new control framework based on the barrier Lyapunov function(BLF)is proposed to achieve tracking and obstacle avoidance of UGVS through constraint control.Meanwhile,a control strategy of UGVS for crossing corridors or gaps is designed,which avoids pre-training for specific obstacle scenes and cumbersome path planning for each individual.At last,the stability analysis is provided by the designed Lyapunov function.Simulation results of three different scenes verify the effectiveness of the proposed method.
基金supported by the Youth Projects of the National Social Science Foundation of China(No.23CJL014).
文摘This paper investigates the mechanisms and effects of international transport corridors on the growth of China's environmental goods exports.Using bilateral data between Chinese provinces and their trading partners,this study treats the opening of the China-Europe Railway Express(CRE)as a quasi-experiment and employs a staggered difference-in-differences method for empirical testing.The results show that the opening of the CRE has promoted the growth of China's environmental goods exports.This growth was driven by mechanisms that increased demand in the international market,diversified the export of environmental goods,stimulated environmental innovation,and enhanced China's capacity to supply environmental goods globally.Significant heterogeneity was observed in the trade of environmental goods due to differences in product types,exporting provinces,and importing countries.The findings suggest that the international transport corridors can generate mutual benefits in the trade of environmental goods.
文摘Based on a comprehensive analysis of the domestic academic research on corridors,this paper argues that distinct disciplines define corridors differently,with varying research purposes.Professor Fei Xiaotong advocated that the fundamental purpose of corridor research is to expound on the formation and development of the Chinese nation.Furthermore,the paper provides a detailed analysis of the six major corridors referenced in ethnological research and proposes the use of the concept of"mortise-and-tenon joint"to reinterpret the significant role of these corridors in the formation and development of both the territory of China as a multi-ethnic state and the Chinese nation.
基金We acknowledge the financial support from the Natural Science Project of Anhui Provincial Department of Education[KJ2018ZD047,KJ2018A0504]Anhui Provincial Natural Science Foundation[1908085ME140].
文摘Ventilation corridors in cities can decrease air pollution and alleviate heat island problems but there remains a need to fully assess their effectiveness.Few urban managers have been able to take city-scale approaches to the construction of urban ventilation corridors.This study aimed to introduced the Ventilation Corridor Planning(VCP)model,which is a multi-criteria evaluation method combined with a geographical information system(GIS)to determine where the ventilated environment is most appropriate.Specifically,the VCP model took Bozhou,China as the research object and contained two scales,including mesoscale and local scale.In mesoscale scale,we got three outputs to build urban ventilation corridors,including 1)background wind environment,2)ventilation potential,3)heat island intensity.In local scale,we used traditional computational fluid dynamics(CFD)model to verify the impact of VCP criteria.The results revealed that compared with the traditional CFD model,the proposed VCP model has advantages in establishing a comprehensive evaluation standard.In addition,the application of VCP model in macro and micro also enhances the efficiency of ventilation corridor construction.Overall,this study introduced a effective modeling method to urban ventilation corridors planning,and provide a way to study the urban climate.
基金supported by the National Key Technology R&D Program(2017YFC1200100)the special S&T project on treatment and control of water pollution(2012ZX07202-004)+3 种基金National Natural Science Foundation of China(31901209)China Postdoctoral Science Foundation(2018M641492)Liaoning Natural Science Foundation(20180551024)the Shenyang Science and Technology Bureau(SYSY2016-16,SYSY2017-010).
文摘Aims Riparian corridors play vital roles in the maintenance of biodiversity.Nonetheless,plant species diversity and vegetation coverage in riparian corridors are seriously threatened by increasing pressure owing to livestock consumption and anthropogenic disturbance;even the stability of river courses has been threatened.The establishment of enclosures is a widely used strategy to restore degraded grassland ecosystems,but its impact on degraded herbaceous riparian vegetation and soil properties remains unclear.The aim of this study was to evaluate whether species composition,richness,diversity,and soil properties can be recovered by the enclosure.Methods Twenty long-term monitoring sample plots were set in the Liaohe main stream river,Liaohe main stream river was enclosed for grazing and farmland exclusion in 2012.The height,coverage and individual numbers of plant were recorded for species richness and diversity evaluation from 2012 to 2017;soil nutrients were measured for comparative analysis in 2012 and 2017.We examined the effects of the establishment of enclosures on plant species diversity and soil properties from 2012 to 2017 in the riparian corridors of the Liaohe River system in China.Important Findings Plant species richness and diversity significantly increased from 2012 to 2017.The dominance of Asteraceae plants increased,while the abundance of Gramineae plants decreased over time.The difference in abundance increased each year since enclosure was implemented in 2012.The concentrations of phosphorus and potassium in the soil significantly decreased as a result of the combined effects of vegetation restoration and prohibition of farming practices following the establishment of enclosures.There was also a lag time related to the response of soil organic matter to the establishment of enclosures.In conclusion,our study provides new evidence regarding the response of species diversity,species composition and soil properties following riparian vegetation restoration efforts through enclosure development.
基金supported by the National Natural Science Foundation of China(No.62203256)。
文摘Generating dynamically feasible trajectory for fixed-wing Unmanned Aerial Vehicles(UAVs)in dense obstacle environments remains computationally intractable.This paper proposes a Safe Flight Corridor constrained Sequential Convex Programming(SFC-SCP)to improve the computation efficiency and reliability of trajectory generation.SFC-SCP combines the front-end convex polyhedron SFC construction and back-end SCP-based trajectory optimization.A Sparse A^(*)Search(SAS)driven SFC construction method is designed to efficiently generate polyhedron SFC according to the geometric relation among obstacles and collision-free waypoints.Via transforming the nonconvex obstacle-avoidance constraints to linear inequality constraints,SFC can mitigate infeasibility of trajectory planning and reduce computation complexity.Then,SCP casts the nonlinear trajectory optimization subject to SFC into convex programming subproblems to decrease the problem complexity.In addition,a convex optimizer based on interior point method is customized,where the search direction is calculated via successive elimination to further improve efficiency.Simulation experiments on dense obstacle scenarios show that SFC-SCP can generate dynamically feasible safe trajectory rapidly.Comparative studies with state-of-the-art SCP-based methods demonstrate the efficiency and reliability merits of SFC-SCP.Besides,the customized convex optimizer outperforms off-the-shelf optimizers in terms of computation time.
基金supported by the Science Fund for the Gansu Provincial Natural Science Foundation Project(22JR5RA339).
文摘Land use/cover change(LUCC)constitutes the spatial and temporal patterns of ecological security,and the construction of ecological networks is an effective way to ensure ecological security.Exploring the spatial and temporal change characteristics of ecological network and analyzing the integrated relationship between LUCC and ecological security are crucial for ensuring regional ecological security.Gansu is one of the provinces with fragile ecological environment in China,and rapid changes in land use patterns in recent decades have threatened ecological security.Therefore,taking Gansu Province as the study area,this study simulated its land use pattern in 2050 using patch-generating land use simulation(PLUS)model based on the LUCC trend from 2000 to 2020 and integrated the LUCC into morphological spatial pattern analysis(MSPA)to identify ecological sources and extract the ecological corridors to construct ecological network using circuit theory.The results revealed that,according to the prediction results in 2050,the areas of cultivated land,forest land,grassland,water body,construction land,and unused land would be 63,447.52,39,510.80,148,115.18,4605.21,8368.89,and 161,752.40 km^(2),respectively.The number of ecological sources in Gansu Province would increase to 80,with a total area of 99,927.18 km^(2).The number of ecological corridors would increase to 191,with an estimated total length of 6120.66 km.Both ecological sources and ecological corridors showed a sparse distribution in the northwest and dense distribution in the southeast of the province at the spatial scale.The number of ecological pinch points would reach 312 and the total area would expect to increase to 842.84 km^(2),with the most pronounced increase in the Longdong region.Compared with 2020,the number and area of ecological barriers in 2050 would decrease significantly by 63 and 370.71 km^(2),respectively.In general,based on the prediction results,the connectivity of ecological network of Gansu Province would increase in 2050.To achieve the predicted ecological network in 2050,emphasis should be placed on the protection of cultivated land and ecological land,the establishment of ecological sources in desert areas,the reinforcement of the protection for existing ecological sources,and the construction of ecological corridors to enhance the stability of ecological network.This study provides valuable theoretical support and references for the future construction of ecological networks and regional land resource management decision-making.
基金funded by the Xinjiang Uygur Autonomous Region Tianshan Talent Training Program(2023TSYCLJ0047)the Natural Science Foundation of Xinjiang Uygur Autonomous Region(2023D01D18)+1 种基金the Key Research and Development Project of Xinjiang(2022B03024-1)the Science and Technology Planning Project of Xinjiang Production and Construction Corps(2022DB023)。
文摘Scientifically constructing an ecological security pattern(ESP)is an important spatial analysis approach to improve ecological functions in arid areas and achieve sustainable development.However,previous research methods ignored the complex trade-offs between ecosystem services in the process of constructing ESP.Taking the mainstream of the Tarim River Basin(MTRB),China as the study area,this study set seven risk scenarios by applying Ordered Weighted Averaging(OWA)model to trade-off the importance of the four ecosystem services adopted by this study(water conservation,carbon storage,habitat quality,and biodiversity conservation),thereby identifying priority protection areas for ecosystem services.And then,this study identified ecological sources by integrating ecosystem service importance with eco-environmental sensitivity.Using circuit theory,the ecological corridors and nodes were extracted to construct the ESP.The results revealed significant spatial heterogeneity in the four ecosystem services across the study area,primarily driven by hydrological gradients and human activity intensity.The ESP of the MTRB included 34 ecological sources with a total area of 1471.38 km^(2),66 ecological corridors with a length of about 1597.45 km,11 ecological pinch points,and 13 ecological barrier points distributed on the ecological corridors.The spatial differentiation of the ESP was obvious,with the upper and middle reaches of the MTRB having a large number of ecological sources and exhibiting higher clustering of ecological corridors compared with the lower reaches.The upper and middle reaches require ecological protection to sustain the existing ecosystem,while the lower reaches need to carry out ecological restoration measures including desertification control.Overall,this study makes up for the shortcomings of constructing ESP simply by spatial superposition of ecosystem service functions and can effectively improve the robustness and stability of ESP construction.
基金Major Program of National Fund of Philosophy and Social Science of China(24&ZD148).
文摘Global climate warming has placed immense pressure on the ecological environment worldwide,and the ecological issues affecting the quality of the living environment have garnered widespread attention.In this context,the question of“how to effectively optimize regional ecological network patterns”has become one of the critical issues that urban and rural planning and ecological geography need to address.This study takes Huzhou,Zhejiang Province,China,as the research area,and uses a combination of landscape type transition matrices and landscape pattern indices to analyze the evolution characteristics of green space landscape patterns from 2017 to 2022.Through geographical detectors and GBDT(Gradient Boosting Decision Tree)algorithms,the study explores the driving factors behind the changes in green space landscape patterns.Based on MSPA(Morphological Spatial Pattern Analysis),key ecological sources in Huzhou are extracted.Using a combination of resistance surfaces and gravity models,ecological corridors and networks are constructed.The study also provides suggestions for the evaluation and optimization of ecological network patterns.The aim is to summarize generalizable patterns of green space landscape evolution and methods for constructing and optimizing regional ecological corridor networks,offering insights and references for the improvement of the living environment and the construction of ecological civilization.
基金The NSFC-INSF Joint Research Project,No.42261144670The Second Tibetan Plateau Scientific Expedition and Research Program,No.2019QZKK0601。
文摘The Inner Asian Mountain Corridor(IAMC)acted as a crossroads of trans-Eurasian exchange since approximately 6000 cal.yr BP.The history of the introduction and utilization of crops and livestock in the area has been intensively discussed,while geographical-temporal variations of human activities and subsistence strategies remain unclear.Here we report new zooarchaeological data and radiocarbon dates from the Naba Cemeteries,revealing herbivorous livestock were predominant animal resource during both the Bronze and Early Iron Ages,and sheep/goat and horse were paramount sacrificial animals in these two periods,respectively.In tandem with published radiocarbon dates,zooarchaeological and archaeobotanical data from IAMC's prehistoric sites,we detect humans mainly engaged in hunting-gathering games in the IAMC during 8000-5000 cal.yr BP.During 5000-4000 cal.yr BP,the territory of agro-pastoral groups evidently expanded in the IAMC with a hotspot in the Altai Region,and wheat and barley were introduced into the area.In the following two millennia,herding became an economic mainstay,and cultivations of crops were ubiquitous in the IAMC's oases.We argue that prehistoric human activities in the IAMC were mainly affected by agro-pastoral expansions associated with exchanges across the Eurasia,which was likely promoted by climate change.
