An improved method using kernel density estimation （KDE） and confidence level is presented for model validation with small samples. Decision making is a challenging problem because of input uncertainty and only smal...An improved method using kernel density estimation （KDE） and confidence level is presented for model validation with small samples. Decision making is a challenging problem because of input uncertainty and only small samples can be used due to the high costs of experimental measurements. However, model validation provides more confidence for decision makers when improving prediction accuracy at the same time. The confidence level method is introduced and the optimum sample variance is determined using a new method in kernel density estimation to increase the credibility of model validation. As a numerical example, the static frame model validation challenge problem presented by Sandia National Laboratories has been chosen. The optimum bandwidth is selected in kernel density estimation in order to build the probability model based on the calibration data. The model assessment is achieved using validation and accreditation experimental data respectively based on the probability model. Finally, the target structure prediction is performed using validated model, which are consistent with the results obtained by other researchers. The results demonstrate that the method using the improved confidence level and kernel density estimation is an effective approach to solve the model validation problem with small samples.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
Taking the Ming Tombs Forest Farm in Beijing as the research object,this research applied multi-source data fusion and GIS heat-map overlay analysis techniques,systematically collected bird observation point data from...Taking the Ming Tombs Forest Farm in Beijing as the research object,this research applied multi-source data fusion and GIS heat-map overlay analysis techniques,systematically collected bird observation point data from the Global Biodiversity Information Facility(GBIF),population distribution data from the Oak Ridge National Laboratory(ORNL)in the United States,as well as information on the composition of tree species in suitable forest areas for birds and the forest geographical information of the Ming Tombs Forest Farm,which is based on literature research and field investigations.By using GIS technology,spatial processing was carried out on bird observation points and population distribution data to identify suitable bird-watching areas in different seasons.Then,according to the suitability value range,these areas were classified into different grades(from unsuitable to highly suitable).The research findings indicated that there was significant spatial heterogeneity in the bird-watching suitability of the Ming Tombs Forest Farm.The north side of the reservoir was generally a core area with high suitability in all seasons.The deep-aged broad-leaved mixed forests supported the overlapping co-existence of the ecological niches of various bird species,such as the Zosterops simplex and Urocissa erythrorhyncha.In contrast,the shallow forest-edge coniferous pure forests and mixed forests were more suitable for specialized species like Carduelis sinica.The southern urban area and the core area of the mausoleums had relatively low suitability due to ecological fragmentation or human interference.Based on these results,this paper proposed a three-level protection framework of“core area conservation—buffer zone management—isolation zone construction”and a spatio-temporal coordinated human-bird co-existence strategy.It was also suggested that the human-bird co-existence space could be optimized through measures such as constructing sound and light buffer interfaces,restoring ecological corridors,and integrating cultural heritage elements.This research provided an operational technical approach and decision-making support for the scientific planning of bird-watching sites and the coordination of ecological protection and tourism development.展开更多
As a key node for the surrounding area,metro stations are closely connected with the surrounding urban space and develop cooperatively.Different types of metro stations have differences in land use and functional posi...As a key node for the surrounding area,metro stations are closely connected with the surrounding urban space and develop cooperatively.Different types of metro stations have differences in land use and functional positioning.This paper mainly used the methods of Tyson polygon,kernel density analysis and correlation analysis,based on POI data,to classify the stations of Beijing Metro Line 7.This paper made a detailed analysis of commercial subway stations,and analyzed the distribution characteristics of commercial metro stations on Line 7.展开更多
There is a growing concern in traffic accident rate in recent years. Using Mashhad city （Iran second populous city） traffic accident records as case study, this paper applied the combi- nation of geo-information tec...There is a growing concern in traffic accident rate in recent years. Using Mashhad city （Iran second populous city） traffic accident records as case study, this paper applied the combi- nation of geo-information technology and spatial-statistical analysis to bring out the influence of spatial factors in their formation. The aim of the study is to examine 4 clustering analyses to have a better understanding of traffic accidents patterns in complex urban network. In order to deploy the clustering technique in urban roads, 9331 point features for inner city traffic accidents during 12 months have been registered according to their x and y location in geographic information system （GIS）. The mentioned areas were analyzed by kernel density estimation （KDE） using ARCMAP and two other analyses using SANET 4th edition software so that the results of network analysis can be compared with traditional KDE method. In addi- tion, this research introduces five classifications for determining the eventfulness of the under study area based on standard deviation and to make priority in creating security in the area. The nearest neighbor and K-function output analysis consist of four curves and regarding the fact that for all fatal, injury and property damage only crashes, the observed value curve is above the 5% confidence interval. Accidents in the study region are more clustered than ex- pected by random chance. The importance of this study is to use GIS as a management system for accident analysis by combination of spatial-statistical methods.展开更多
基金Funding of Jiangsu Innovation Program for Graduate Education (CXZZ11_0193)NUAA Research Funding (NJ2010009)
文摘An improved method using kernel density estimation （KDE） and confidence level is presented for model validation with small samples. Decision making is a challenging problem because of input uncertainty and only small samples can be used due to the high costs of experimental measurements. However, model validation provides more confidence for decision makers when improving prediction accuracy at the same time. The confidence level method is introduced and the optimum sample variance is determined using a new method in kernel density estimation to increase the credibility of model validation. As a numerical example, the static frame model validation challenge problem presented by Sandia National Laboratories has been chosen. The optimum bandwidth is selected in kernel density estimation in order to build the probability model based on the calibration data. The model assessment is achieved using validation and accreditation experimental data respectively based on the probability model. Finally, the target structure prediction is performed using validated model, which are consistent with the results obtained by other researchers. The results demonstrate that the method using the improved confidence level and kernel density estimation is an effective approach to solve the model validation problem with small samples.
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Sponsored by Beijing Youth Innovation Talent Support Program for Urban Greening and Landscaping——The 2024 Special Project for Promoting High-Quality Development of Beijing’s Landscaping through Scientific and Technological Innovation(KJCXQT202410).
文摘Taking the Ming Tombs Forest Farm in Beijing as the research object,this research applied multi-source data fusion and GIS heat-map overlay analysis techniques,systematically collected bird observation point data from the Global Biodiversity Information Facility(GBIF),population distribution data from the Oak Ridge National Laboratory(ORNL)in the United States,as well as information on the composition of tree species in suitable forest areas for birds and the forest geographical information of the Ming Tombs Forest Farm,which is based on literature research and field investigations.By using GIS technology,spatial processing was carried out on bird observation points and population distribution data to identify suitable bird-watching areas in different seasons.Then,according to the suitability value range,these areas were classified into different grades(from unsuitable to highly suitable).The research findings indicated that there was significant spatial heterogeneity in the bird-watching suitability of the Ming Tombs Forest Farm.The north side of the reservoir was generally a core area with high suitability in all seasons.The deep-aged broad-leaved mixed forests supported the overlapping co-existence of the ecological niches of various bird species,such as the Zosterops simplex and Urocissa erythrorhyncha.In contrast,the shallow forest-edge coniferous pure forests and mixed forests were more suitable for specialized species like Carduelis sinica.The southern urban area and the core area of the mausoleums had relatively low suitability due to ecological fragmentation or human interference.Based on these results,this paper proposed a three-level protection framework of“core area conservation—buffer zone management—isolation zone construction”and a spatio-temporal coordinated human-bird co-existence strategy.It was also suggested that the human-bird co-existence space could be optimized through measures such as constructing sound and light buffer interfaces,restoring ecological corridors,and integrating cultural heritage elements.This research provided an operational technical approach and decision-making support for the scientific planning of bird-watching sites and the coordination of ecological protection and tourism development.
基金Beijing Municipal Social Science Foundation(22GLC062).
文摘As a key node for the surrounding area,metro stations are closely connected with the surrounding urban space and develop cooperatively.Different types of metro stations have differences in land use and functional positioning.This paper mainly used the methods of Tyson polygon,kernel density analysis and correlation analysis,based on POI data,to classify the stations of Beijing Metro Line 7.This paper made a detailed analysis of commercial subway stations,and analyzed the distribution characteristics of commercial metro stations on Line 7.
文摘There is a growing concern in traffic accident rate in recent years. Using Mashhad city （Iran second populous city） traffic accident records as case study, this paper applied the combi- nation of geo-information technology and spatial-statistical analysis to bring out the influence of spatial factors in their formation. The aim of the study is to examine 4 clustering analyses to have a better understanding of traffic accidents patterns in complex urban network. In order to deploy the clustering technique in urban roads, 9331 point features for inner city traffic accidents during 12 months have been registered according to their x and y location in geographic information system （GIS）. The mentioned areas were analyzed by kernel density estimation （KDE） using ARCMAP and two other analyses using SANET 4th edition software so that the results of network analysis can be compared with traditional KDE method. In addi- tion, this research introduces five classifications for determining the eventfulness of the under study area based on standard deviation and to make priority in creating security in the area. The nearest neighbor and K-function output analysis consist of four curves and regarding the fact that for all fatal, injury and property damage only crashes, the observed value curve is above the 5% confidence interval. Accidents in the study region are more clustered than ex- pected by random chance. The importance of this study is to use GIS as a management system for accident analysis by combination of spatial-statistical methods.
