Data is undoubtedly becoming a commodity like oil,land,and labour in the 21st century.Although there have been many successful marketplaces for data trading,the existing data marketplaces lack consideration of the cas...Data is undoubtedly becoming a commodity like oil,land,and labour in the 21st century.Although there have been many successful marketplaces for data trading,the existing data marketplaces lack consideration of the case where buyers want to acquire a collection of datasets(instead of one),and the overall spatial coverage and connectivity matter.In this paper,we make the first attempt to formulate this problem as Budgeted Maximum Coverage with Connectivity Constraint(BMCC),which aims to acquire a dataset collection with the maximum spatial coverage under a limited budget while maintaining spatial connectivity.To solve the problem,we propose two approximate algorithms with detailed theoretical guarantees and time complexity analysis,followed by two acceleration strategies to further improve the efficiency of the algorithm.Experiments are conducted on five real-world spatial dataset collections to verify the efficiency and effectiveness of our algorithms.展开更多
On the basis of analyzing yearly data and spatial relationships between tourism spots, star hotels and travel agencies of Hainan Province, and comparing all the methods of measuring industrial spatial agglomeration, t...On the basis of analyzing yearly data and spatial relationships between tourism spots, star hotels and travel agencies of Hainan Province, and comparing all the methods of measuring industrial spatial agglomeration, this paper chose Hefindahl index, Location Quotient, nearest neighbor index, spatial connection index and geographic concentration index to measure Hainan tourism agglomeration. By applying these methods, total tourism agglomeration, agglomeration of tourism factors and regional agglomeration differences were studied. The results showed that the overall agglomeration increases as time flows, and the eastern part is the most agglomerated, the west takes the second, with the middle ranking the least. The large-scale agglomeration regions are Sanya and Haikou. The influencing factors of Hainan tourism spatial agglomeration were concluded as tourism resource endowment, industrial attributes, geographic conditions, governmental policies and the overall economic development level, etc. In addition, the paper proposed tourism spatial agglomeration modes of Hainan Province at various spatial scales.展开更多
It is well established that complex networks are responsible for the high-level information processing in the human brain.The topology of complex networks allows efficient dynamic interactions between spatially distin...It is well established that complex networks are responsible for the high-level information processing in the human brain.The topology of complex networks allows efficient dynamic interactions between spatially distinct brain areas,which may be studied by analyzing the topological展开更多
The aim of this work is to explore the impact of regional transit service on tour-based commuter travel behavior by using the Bayesian hierarchical multinomial logit model, accounting for the spatial heterogeneity of ...The aim of this work is to explore the impact of regional transit service on tour-based commuter travel behavior by using the Bayesian hierarchical multinomial logit model, accounting for the spatial heterogeneity of the people living in the same area.With two indicators, accessibility and connectivity measured at the zone level, the regional transit service is captured and then related to the travel mode choice behavior. The sample data are selected from Washington-Baltimore Household Travel Survey in 2007,including all the trips from home to workplace in morning hours in Baltimore city. Traditional multinomial logit model using Bayesian approach is also estimated. A comparison of the two different models shows that ignoring the spatial context can lead to a misspecification of the effects of the regional transit service on travel behavior. The results reveal that improving transit service at regional level can be effective in reducing auto use for commuters after controlling for socio-demographics and travel-related factors.This work provides insights for interpreting tour-based commuter travel behavior by using recently developed methodological approaches. The results of this work will be helpful for engineers, urban planners, and transit operators to decide the needs to improve regional transit service and spatial location efficiently.展开更多
Background In response to the growing ecological crises driven by rapid urbanization,nature-based solutions(NBS)have gained increasing attention,particularly from the perspective of coupled social-ecological systems.U...Background In response to the growing ecological crises driven by rapid urbanization,nature-based solutions(NBS)have gained increasing attention,particularly from the perspective of coupled social-ecological systems.Understanding the dynamic interactions between urban expansion and ecosystems is essential for promoting sustainable development.This study investigated the spatio-temporal effects of urban expansion on ecological security patterns(ESPs)through the lens of land use.By integrating urban growth simulation with ESP analysis,we examined how urban expansion influenced the temporal adaptation and spatial connectivity of ESPs in the rapidly developing Wuhan Metropolitan Area(WMA),China.Results From 2000 to 2020,urban land in the WMA expanded rapidly,characterized by a diffusion pattern dominated by edge-expansion.During this period,the ESPs were characterized by an increase in the area of ecological sources,the extension of ecological corridors,and the expansion of pinchpoint and barrier zones.Urban expansion showed limited direct impact on ecological sources but exerted stronger indirect effects through the displacement of cropland.Although projections indicate that the rate of urban expansion may slow and urban form may tend toward coalescence by 2030 under the natural development scenario(NDS),the threat to high-quality ecological sources remains.Moreover,the direct disruption of ecological corridors is expected to persist and intensify in critical zones,undermining spatial connectivity.Conclusions To mitigate the ecological impacts of urban growth,targeted ecological conservation and restoration strategies should be implemented,particularly through ecological source zoning and landscape classification at pinchpoints and barriers.Promoting compact urban forms and coordinating land use strategies across cities are essential to minimizing ecological trade-offs.This study provided practical insights for harmonizing urban growth with ecological conservation in rapidly urbanizing regions.展开更多
Similar to species immigration or exotic species invasion,infectious disease transmis-sion is strengthened due to the globalization of human activities.Using schistosomiasis as an exam-ple,we propose a conceptual mode...Similar to species immigration or exotic species invasion,infectious disease transmis-sion is strengthened due to the globalization of human activities.Using schistosomiasis as an exam-ple,we propose a conceptual model simulating the spatio-temporal dynamics of infectious diseases.We base the model on the knowledge of the interrelationship among the source,media,and the hosts of the disease.With the endemics data of schistosomiasis in Xichang,China,we demonstrate that the conceptual model is feasible;we introduce how remote sensing and geographic information systems techniques can be used in support of spatio-temporal modeling;we compare the different effects caused to the entire population when selecting different groups of people for schistosomiasis control.Our work illustrates the importance of such a modeling tool in supporting spatial decisions.Our mod-eling method can be directly applied to such infectious diseases as the plague,lyme disease,and hemorrhagic fever with renal syndrome.The application of remote sensing and geographic informa-tion systems can shed light on the modeling of other infectious disease and invasive species studies.展开更多
The environmental factors that influence tree-grass abundances in tropical savanna and grasslands are not well understood,particularly for woodland-grassland mosaics in humid zones.We studied the effects of abiotic an...The environmental factors that influence tree-grass abundances in tropical savanna and grasslands are not well understood,particularly for woodland-grassland mosaics in humid zones.We studied the effects of abiotic and spatial variables on woody and herbaceous species distributions in a Terai ecosystem of northeastern India.We evaluated the importance of climatic and non-climatic factors that maintain variable tree-grass ratios across the landscape,and also accounted for spatial connectivity and dispersal.We measured species abundances of woody and herbaceous plant species in 134 plots with each 30 m×30 m in a 519 km^(2)protected Terai habitat,and derived several climatic and non-climatic environmental factors.We constructed variables based on different models of spatial connectivity among sites,to test their influence on species abundances.We then used redundancy analyses and variation partitioning to quantify the importance of environmental variables and spatial structure on variation in tree-grass abundances.We found that environmental variables including rainfall,fire,water stress,topography and soil nutrients had statistically significant effects on species abundance and tree-grass ratios.Spatial structure was significant,and the best spatial model was an inverse distance-weighted model with linkage extending to 23.5 km,indicating weak dispersal limitation.About 21%of the variation in species abundance was explained by the selected environmental and spatial factors.The results indicate that dynamic plant communities in which spatial-temporal variation in environmental factors may drive stochasticity in species distribution and abundance,thus dominantly influencing on the vegetation mosaic.展开更多
基金supported by the National Key R&D Program of China(Grant No.2023YFB4503600)the National Natural Science Foundation of China(Grant Nos.62202338 and 62372337)the Key R&D Program of Hubei Province(Grant No.2023BAB081).
文摘Data is undoubtedly becoming a commodity like oil,land,and labour in the 21st century.Although there have been many successful marketplaces for data trading,the existing data marketplaces lack consideration of the case where buyers want to acquire a collection of datasets(instead of one),and the overall spatial coverage and connectivity matter.In this paper,we make the first attempt to formulate this problem as Budgeted Maximum Coverage with Connectivity Constraint(BMCC),which aims to acquire a dataset collection with the maximum spatial coverage under a limited budget while maintaining spatial connectivity.To solve the problem,we propose two approximate algorithms with detailed theoretical guarantees and time complexity analysis,followed by two acceleration strategies to further improve the efficiency of the algorithm.Experiments are conducted on five real-world spatial dataset collections to verify the efficiency and effectiveness of our algorithms.
基金Sponsored by National Natural Science Foundation of China(51309134)Research Starting Funds for Imported TalentsNingxia University(BQD2012011)
文摘On the basis of analyzing yearly data and spatial relationships between tourism spots, star hotels and travel agencies of Hainan Province, and comparing all the methods of measuring industrial spatial agglomeration, this paper chose Hefindahl index, Location Quotient, nearest neighbor index, spatial connection index and geographic concentration index to measure Hainan tourism agglomeration. By applying these methods, total tourism agglomeration, agglomeration of tourism factors and regional agglomeration differences were studied. The results showed that the overall agglomeration increases as time flows, and the eastern part is the most agglomerated, the west takes the second, with the middle ranking the least. The large-scale agglomeration regions are Sanya and Haikou. The influencing factors of Hainan tourism spatial agglomeration were concluded as tourism resource endowment, industrial attributes, geographic conditions, governmental policies and the overall economic development level, etc. In addition, the paper proposed tourism spatial agglomeration modes of Hainan Province at various spatial scales.
文摘It is well established that complex networks are responsible for the high-level information processing in the human brain.The topology of complex networks allows efficient dynamic interactions between spatially distinct brain areas,which may be studied by analyzing the topological
基金Project(71173061)supported by the National Natural Science Foundation of ChinaProject(2013U-6)supported by Key Laboratory of Eco Planning & Green Building,Ministry of Education(Tsinghua University),China
文摘The aim of this work is to explore the impact of regional transit service on tour-based commuter travel behavior by using the Bayesian hierarchical multinomial logit model, accounting for the spatial heterogeneity of the people living in the same area.With two indicators, accessibility and connectivity measured at the zone level, the regional transit service is captured and then related to the travel mode choice behavior. The sample data are selected from Washington-Baltimore Household Travel Survey in 2007,including all the trips from home to workplace in morning hours in Baltimore city. Traditional multinomial logit model using Bayesian approach is also estimated. A comparison of the two different models shows that ignoring the spatial context can lead to a misspecification of the effects of the regional transit service on travel behavior. The results reveal that improving transit service at regional level can be effective in reducing auto use for commuters after controlling for socio-demographics and travel-related factors.This work provides insights for interpreting tour-based commuter travel behavior by using recently developed methodological approaches. The results of this work will be helpful for engineers, urban planners, and transit operators to decide the needs to improve regional transit service and spatial location efficiently.
基金supported by the National Natural Science Foundation of China(Grant Nos.42230107 and 42401323)the China Postdoctoral Science Foundation(Grant Nos.2024M762497 and 2025T180197)the Postdoctoral Project of Hubei Provice(Grant No.2024HBBHCXB068)
文摘Background In response to the growing ecological crises driven by rapid urbanization,nature-based solutions(NBS)have gained increasing attention,particularly from the perspective of coupled social-ecological systems.Understanding the dynamic interactions between urban expansion and ecosystems is essential for promoting sustainable development.This study investigated the spatio-temporal effects of urban expansion on ecological security patterns(ESPs)through the lens of land use.By integrating urban growth simulation with ESP analysis,we examined how urban expansion influenced the temporal adaptation and spatial connectivity of ESPs in the rapidly developing Wuhan Metropolitan Area(WMA),China.Results From 2000 to 2020,urban land in the WMA expanded rapidly,characterized by a diffusion pattern dominated by edge-expansion.During this period,the ESPs were characterized by an increase in the area of ecological sources,the extension of ecological corridors,and the expansion of pinchpoint and barrier zones.Urban expansion showed limited direct impact on ecological sources but exerted stronger indirect effects through the displacement of cropland.Although projections indicate that the rate of urban expansion may slow and urban form may tend toward coalescence by 2030 under the natural development scenario(NDS),the threat to high-quality ecological sources remains.Moreover,the direct disruption of ecological corridors is expected to persist and intensify in critical zones,undermining spatial connectivity.Conclusions To mitigate the ecological impacts of urban growth,targeted ecological conservation and restoration strategies should be implemented,particularly through ecological source zoning and landscape classification at pinchpoints and barriers.Promoting compact urban forms and coordinating land use strategies across cities are essential to minimizing ecological trade-offs.This study provided practical insights for harmonizing urban growth with ecological conservation in rapidly urbanizing regions.
基金partially supported by the National Natural Science Foundation of China(Grant No.30590370)the Tenth-Five-Year Key Project(Grant No.2004BA718B06)and an NIH(Grant No.RO1-AI-43961).
文摘Similar to species immigration or exotic species invasion,infectious disease transmis-sion is strengthened due to the globalization of human activities.Using schistosomiasis as an exam-ple,we propose a conceptual model simulating the spatio-temporal dynamics of infectious diseases.We base the model on the knowledge of the interrelationship among the source,media,and the hosts of the disease.With the endemics data of schistosomiasis in Xichang,China,we demonstrate that the conceptual model is feasible;we introduce how remote sensing and geographic information systems techniques can be used in support of spatio-temporal modeling;we compare the different effects caused to the entire population when selecting different groups of people for schistosomiasis control.Our work illustrates the importance of such a modeling tool in supporting spatial decisions.Our mod-eling method can be directly applied to such infectious diseases as the plague,lyme disease,and hemorrhagic fever with renal syndrome.The application of remote sensing and geographic informa-tion systems can shed light on the modeling of other infectious disease and invasive species studies.
基金We thank the UNESCO World Heritage Sites Program and the United States Fish and Wildlife Service Tiger Conservation Grant Program(F12AP00312)for financial support to carry out this work.
文摘The environmental factors that influence tree-grass abundances in tropical savanna and grasslands are not well understood,particularly for woodland-grassland mosaics in humid zones.We studied the effects of abiotic and spatial variables on woody and herbaceous species distributions in a Terai ecosystem of northeastern India.We evaluated the importance of climatic and non-climatic factors that maintain variable tree-grass ratios across the landscape,and also accounted for spatial connectivity and dispersal.We measured species abundances of woody and herbaceous plant species in 134 plots with each 30 m×30 m in a 519 km^(2)protected Terai habitat,and derived several climatic and non-climatic environmental factors.We constructed variables based on different models of spatial connectivity among sites,to test their influence on species abundances.We then used redundancy analyses and variation partitioning to quantify the importance of environmental variables and spatial structure on variation in tree-grass abundances.We found that environmental variables including rainfall,fire,water stress,topography and soil nutrients had statistically significant effects on species abundance and tree-grass ratios.Spatial structure was significant,and the best spatial model was an inverse distance-weighted model with linkage extending to 23.5 km,indicating weak dispersal limitation.About 21%of the variation in species abundance was explained by the selected environmental and spatial factors.The results indicate that dynamic plant communities in which spatial-temporal variation in environmental factors may drive stochasticity in species distribution and abundance,thus dominantly influencing on the vegetation mosaic.
