The spatialization of population of counties in China is significant. Firstly, we can gain the estimated values of population density adaptive to different kinds of regions. Secondly, we can integrate effectively popu...The spatialization of population of counties in China is significant. Firstly, we can gain the estimated values of population density adaptive to different kinds of regions. Secondly, we can integrate effectively population data with other data including natural resources, environment, society and economy, build 1km GRIDs of natural resources reserves per person, population density and other economic and environmental data, which are necessary to the national management and macro adjustment and control of natural resources and dynamic monitoring of population. In order to establish population information system serving national decision making, three steps ought to be followed:1) establishing complete geographical spatial data foundation infrastructure including the establishment of electric map of residence with high resolution using topographical map with large scale and high resolution satellite remote sensing data, the determination of attribute information of housing and office buildings, and creating complete set of attribute database and rapid data updating; 2) establishing complete census systems including improving the transformation efficiency from census data to digital database and strengthening the link of census database and geographical spatial database, meanwhile, the government should attach great importance to the establishment and integration of population migration database; 3) considering there is no GIS software specially serving the analysis and management of population data, a practical approach is to add special modules to present software system, which works as a bridge actualizing the digitization and spatialization of population geography research.展开更多
By using the observation data of drought,storm and hail in Dalian in recent 30 years,the spatialization of major agriculture meteorological disasters were carried out by means of cokriging and plate smooth slice splin...By using the observation data of drought,storm and hail in Dalian in recent 30 years,the spatialization of major agriculture meteorological disasters were carried out by means of cokriging and plate smooth slice spline method.Based on the 1:250 000 geographical information data in Dalian City,major meteorological disasters were spatially analyzed by using ArcMap,and the thematic map overlaying disaster distribution and crop information was made.Taking the distribution of hail disaster and crop yield for example,the application of spatialization method of agriculture meteorological disasters was elaborated.The results could provide decision basis for the establishment of disaster prevention and reduction and the optimization of crop distribution in Dalian.展开更多
Population and housing grid data spatialization hased on 340 grid samples （ 1 kmx 1 kin） is used in- stead of regional statistical data to simulate the population and housing distribution data of Yunnan Province （ ...Population and housing grid data spatialization hased on 340 grid samples （ 1 kmx 1 kin） is used in- stead of regional statistical data to simulate the population and housing distribution data of Yunnan Province （ 1 km×1 kin） for rapid loss assessment ibr the Jinggu Ms6.6 earthquake. The resuhs indicate that the method reflects the actual population and housing distribution and that the assessment results are eredihle. The method can be used to quickly provide spatial orientation disaster information after an earthquake.展开更多
Recently,the expertise accumulated in the field of geovisualization has found application in the visualization of abstract multidimensional data,on the basis of methods called spatialization methods.Spatialization met...Recently,the expertise accumulated in the field of geovisualization has found application in the visualization of abstract multidimensional data,on the basis of methods called spatialization methods.Spatialization methods aim at visualizing multidimensional data into low-dimensional representational spaces by making use of spatial metaphors and applying dimension reduction techniques.Spatial metaphors are able to provide a metaphoric framework for the visualization of information at different levels of granularity.The present paper makes an investigation on how the issue of granularity is handled in the context of representative examples of spatialization methods.Furthermore,this paper introduces the prototyping tool Geo-Scape,which provides an interactive spatialization environment for representing and exploring multidimensional data at different levels of granularity,by making use of a kernel density estimation technique and on the landscape "smoothness" metaphor.A demonstration scenario is presented next to show how Geo-Scape helps to discover knowledge into a large set of data,by grouping them into meaningful clusters on the basis of a similarity measure and organizing them at different levels of granularity.展开更多
In this paper the application of spatialization technology on metadata quality check and updating was dis-cussed. A new method based on spatialization was proposed for checking and updating metadata to overcome the de...In this paper the application of spatialization technology on metadata quality check and updating was dis-cussed. A new method based on spatialization was proposed for checking and updating metadata to overcome the defi-ciency of text based methods with the powerful functions of spatial query and analysis provided by GIS software. Thismethod employs the technology of spatialization to transform metadata into a coordinate space and the functions ofspatial analysis in GIS to check and update spatial metadata in a visual environment. The basic principle and technicalflow of this method were explained in detail, and an example of implementation using ArcMap of GIS software wasillustrated with a metadata set of digital raster maps. The result shows the new method with the support of interactionof graph and text is much more intuitive and convenient than the ordinary text based method, and can fully utilize thefunctions of GIS spatial query and analysis with more accuracy and efficiency.展开更多
Population spatialization is widely used for spatially downscaling census population data to finer-scale.The core idea of modern population spatialization is to establish the association between ancillary data and pop...Population spatialization is widely used for spatially downscaling census population data to finer-scale.The core idea of modern population spatialization is to establish the association between ancillary data and population at the administrative-unit-level(AUlevel)and transfer it to generate the gridded population.However,the statistical characteristic of attributes at the pixel-level differs from that at the AU-level,thus leading to prediction bias via the cross-scale modeling(i.e.scale mismatch problem).In addition,integrating multi-source data simply as covariates may underutilize spatial semantics,and lead to incorrect population disaggregation;while neglecting the spatial autocorrelation of population generates excessively heterogeneous population distribution that contradicts to real-world situation.To address the scale mismatch in downscaling,this paper proposes a Cross-Scale Feature Construction(CSFC)method.More specifically,by grading pixel-level attributes,we construct the feature vector of pixel grade proportions to narrow the scale differences in feature representation between AU-level and pixel-level.Meanwhile,fine-grained building patch and mobile positioning data are utilized to adjust the population weighting layer generated from POI-density-based regression modeling.Spatial filtering is furtherly adopted to model the spatial autocorrelation effect of population and reduce the heterogeneity in population caused by pixel-level attribute discretization.Through the comparison with traditional feature construction method and the ablation experiments,the results demonstrate significant accuracy improvements in population spatialization and verify the effectiveness of weight correction steps.Furthermore,accuracy comparisons with WorldPop and GPW datasets quantitatively illustrate the advantages of the proposed method in fine-scale population spatialization.展开更多
基于国际比较的地方空间规划的范围和工具研究An International Comparison of the Scope and Instruments of Local Spatial Planning源自:The TownPlanning Review,2024,95(2):197-217作者:MaciejJNowak,StefanieDühr,Sergio Pe&...基于国际比较的地方空间规划的范围和工具研究An International Comparison of the Scope and Instruments of Local Spatial Planning源自:The TownPlanning Review,2024,95(2):197-217作者:MaciejJNowak,StefanieDühr,Sergio Peña,et al.推荐:申明锐,南京大学建筑与城市规划学院。shenmingr@nju.edu.cn.展开更多
针对UAV在仿真实验中自动跟踪移动目标的需求,提出基于改进CSRT(channel and spatial reliability-aware tracker)算法的无人机长时自动跟踪方法。通过导向滤波加拉普拉斯算子LOGF(laplacian of guided filter)检测获取目标边缘特征,再...针对UAV在仿真实验中自动跟踪移动目标的需求,提出基于改进CSRT(channel and spatial reliability-aware tracker)算法的无人机长时自动跟踪方法。通过导向滤波加拉普拉斯算子LOGF(laplacian of guided filter)检测获取目标边缘特征,再与HOG(histogram of oriented gradient)和CN(color names)特征融合,增强算法对目标的判别能力;使用平均峰值相关能量和感知哈希汉明距离来综合判定目标状态,当判定目标被遮挡时,采用YOLOv8定位目标,再将定位结果传输至跟踪算法继续跟踪目标。仿真结果表明:在搭建的仿真环境中算法能够在目标被遮挡时仍能长时稳定的跟踪目标,为无人机目标跟踪算法研究提供了良好的仿真实验环境。展开更多
Laser wakefield accelerators(LWFAs)offer acceleration gradients up to 1000 times higher than those of conventional radio-frequency accelerators,offering a pathway to significantly more compact and cost-effective accel...Laser wakefield accelerators(LWFAs)offer acceleration gradients up to 1000 times higher than those of conventional radio-frequency accelerators,offering a pathway to significantly more compact and cost-effective accelerator systems.This breakthrough opens up new possibilities for laboratory-scale light sources.All-optical inverse Compton scattering(AOCS)sources driven by LWFAs produce high-brightness,quasimonochromatic X rays with micrometer-scale source sizes,delivering the spatial coherence and resolution required for X-ray phase-contrast imaging(XPCI).These features position AOCS X-ray sources as promising tools for applications in biology,medicine,physics,and materials science.However,previous AOCS-based imaging studies have primarily focused on X-ray absorption imaging.In this work,we report successful experimental demonstrations of edge-enhanced in-line XPCI using energy-tunable,quasi-monochromatic AOCS X rays.With a spatial resolution of~20μm,our results clearly show the potential of high-resolution,AOCS-based XPCI applications.展开更多
Owing to intensified globalization and informatization,the structures of the urban scale hierarchy and urban networks between cities have become increasingly intertwined,resulting in different spatial effects.Therefor...Owing to intensified globalization and informatization,the structures of the urban scale hierarchy and urban networks between cities have become increasingly intertwined,resulting in different spatial effects.Therefore,this paper analyzes the spatial interaction between urban scale hierarchy and urban networks in China from 2019 to 2023,drawing on Baidu migration data and employing a spatial simultaneous equation model.The results reveal a significant positive spatial correlation between cities with higher hierarchy and those with greater network centrality.Within a static framework,we identify a positive interaction between urban scale hierarchy and urban network centrality,while their spatial cross-effects manifest as negative neighborhood interactions based on geographical distance and positive cross-scale interactions shaped by network connections.Within a dynamic framework,changes in urban scale hierarchy and urban networks are mutually reinforcing,thereby widening disparities within the urban hierarchy.Furthermore,an increase in a city’s network centrality had a dampening effect on the population growth of neighboring cities and network-connected cities.This study enhances understanding of the spatial organisation of urban systems and offers insights for coordinated regional development.展开更多
The suppression of ablative Rayleigh–Taylor instability(ARTI)by a spatially modulated laser in inertial confinement fusion(ICF)is studied through numerical simulations.The results show that in the acceleration phase ...The suppression of ablative Rayleigh–Taylor instability(ARTI)by a spatially modulated laser in inertial confinement fusion(ICF)is studied through numerical simulations.The results show that in the acceleration phase of ICF implosion,the growth of ARTI can be suppressed by using a short-wavelength spatially modulated laser.The ARTI growth rate decreases as the wavelength of the spatially modulated laser decreases,and ARTI is completely suppressed after a certain wavelength has been reached.A spatially uniform laser is introduced to keep the state of motion of the implosion fluid consistent,and it is found that the proportion of the spatially modulated laser required for complete suppression of ARTI decreases as the wavelength continues to decrease.We also optimize the spatial intensity distribution of the spatially modulated laser.In addition,as the duration of the spatially modulated laser decreases,the proportion required for completely suppressing ARTI increases,but the required energy decreases.When the perturbation wavenumber decreases,the wavelength of the spatially modulated laser required for complete suppression of ARTI becomes longer.In the case of multimode perturbation,ARTI can also be significantly suppressed by a spatially modulated laser,and the perturbation amplitude can be reduced to less than 10% of that without a spatially modulated laser.We believe that the conclusions drawn from our simulations can provide the basis for new approaches to control ARTI in ICF.展开更多
Alzheimer’s disease(AD)is the most common form of dementia.In addition to the lack of effective treatments,there are limitations in diagnostic capabilities.The complexity of AD itself,together with a variety of other...Alzheimer’s disease(AD)is the most common form of dementia.In addition to the lack of effective treatments,there are limitations in diagnostic capabilities.The complexity of AD itself,together with a variety of other diseases often observed in a patient’s history in addition to their AD diagnosis,make deciphering the molecular mechanisms that underlie AD,even more important.Large datasets of single-cell RNA sequencing,single-nucleus RNA-sequencing(snRNA-seq),and spatial transcriptomics(ST)have become essential in guiding and supporting new investigations into the cellular and regional susceptibility of AD.However,with unique technology,software,and larger databases emerging;a lack of integration of these data can contribute to ineffective use of valuable knowledge.Importantly,there was no specialized database that concentrates on ST in AD that offers comprehensive differential analyses under various conditions,such as sex-specific,region-specific,and comparisons between AD and control groups until the new Single-cell and Spatial RNA-seq databasE for Alzheimer’s Disease(ssREAD)database(Wang et al.,2024)was introduced to meet the scientific community’s growing demand for comprehensive,integrated,and accessible data analysis.展开更多
Investigating urban spatial structures(USSs)and their influencing factors at different spatial scales is crucial for promoting sustainable urban transformation.Based on nighttime light datasets and the Herfindahl-Hirs...Investigating urban spatial structures(USSs)and their influencing factors at different spatial scales is crucial for promoting sustainable urban transformation.Based on nighttime light datasets and the Herfindahl-Hirschman index(HHI),this study analyzes USS characteristics in China from 2007 to 2023 on two spatial scales-prefecture-level cities and urban agglomerations.It also explores structural influencing factors,including the economy,infrastructure,society,and government intervention.We find that:(1)HHI values for both cities and urban agglomerations exhibit a decreasing trend,indicating a USS for both that is evolving toward polycentricity;(2)economic development promotes a polycentric structure at both spatial scales,whereas government intervention drives a monocentric structure;and(3)postal and communication infrastructure have conflicting effects on USSs,encouraging a monocentric structure at the city scale but fostering polycentricity at the urban agglomeration scale.展开更多
The integrated nested Laplace approximation(INLA)algorithm provides a computationally efficient approach for approximate Bayesian inference,overcoming the limitations of traditional Markov chain Monte Carlo(MCMC)metho...The integrated nested Laplace approximation(INLA)algorithm provides a computationally efficient approach for approximate Bayesian inference,overcoming the limitations of traditional Markov chain Monte Carlo(MCMC)methods.This paper reviews INLA algorithm and provides a systematic review of six key books that explore the theoretical foundations,practical implementations,and diverse applications of INLA.These six books cover spatial and spatio-temporal modelling,general Bayesian inference,SPDE-based spatial analysis,geospatial health data,regression modelling,and dynamic time series.In addition,these books highlight the versatility of INLA method in handling complex models while maintaining high computational efficiency.This paper begins with an introduction to the INLA method and algorithm,followed by a systematic review of six key publications in the field.展开更多
Two-dimensional materials for flexible energy storage commonly facehuge challenges in limited active surface and hindered charge transport.Herein,wereport an innovative asymmetric pseudocapacitor based on synergistic ...Two-dimensional materials for flexible energy storage commonly facehuge challenges in limited active surface and hindered charge transport.Herein,wereport an innovative asymmetric pseudocapacitor based on synergistic design of modifiedMXene and graphene,integrating gas-induced rapid expansion technology andprecise surface chemical regulation methods.For graphene modification,rapid vaporizationinduces exfoliation and expansion of graphene oxide layers.Subsequently,pseudocapacitiveoxygen-containing groups were selectively introduced through acid oxidation,yielding expanded-and-oxidized graphene(OEG)for positive porous-nanopaperelectrode.For MXene modification,alkali-treated MXene underwent hydrazine assistance to facilitate gas expansion and-NH_(2)grafting,producing MXene-NH_(2)(NOM)for negative porous-nanopaper electrode.Density functional theory calculations show that-COOH moreeffectively modulate graphene’s electronic structure by inducing charge redistribution and creating active sites,thereby enhancing H^(+)adsorption and ion interactions compared to-OH.Meanwhile,-NH_(2)on MXene enable electron delocalization and dynamic Ti-N-H^(+)interactions,speeding up proton adsorption/desorption and boosting both pseudocapacitance and conductivity.Through collaborativeoptimized spatial architecture and surface properties,flexible OEGB and NOMB exhibited of 333.6 and 500.5 F g^(-1)at high mass loading,respectively.The assembled proton pseudocapacitor readily achieved energy and power densities of 58.9 Wh kg^(-1)and 3802 W kg^(-1),respectively,with excellent stability for potential applications.展开更多
Endowed with opportunities from both land and ocean,coastal areas attract expanding human populations and economic activities.At the same time,they face growing societal and environmental pressures from both the above...Endowed with opportunities from both land and ocean,coastal areas attract expanding human populations and economic activities.At the same time,they face growing societal and environmental pressures from both the above river catchments and the bordering sea due to climate change,ecosystem degradation,and expansion of built-up areas.Despite the accumulation of human population,economic activities,and environmental impacts,we lack social-ecological systems analysis on water-related risks to world’s coastal human population.To address this research gap,we analyze the spatial extent of six globally important water stressors to people within the world’s coastal zone(100 km from the coastal line)and classify this zone globally into 12 groups by distance from the coastline and elevation from the mean sea level.Adopting the approaches of the UN Sendai Framework and IPCC,we produce risk maps from the stressor maps by multiplying them with population exposure and vulnerability.For most risks,geographical hotspots are the Chinese coast,Bay of Bengal,Gujarat,and the Island of Java.The analysis reveals fundamental differences between water stressors and related risks,often mixed in scholarly literature.Both manifest specific geographic patterns and latitudinal profiles.Our study highlights the importance of high-resolution spatial analysis of vulnerability,exposure,and risks posed by water related stressors in the world’s coastal zone,in a manner prompted by key policy bodies to promote policy design and shared responsibility for managing stress-prone areas.展开更多
Water infiltration in loess is one of the most significant processes that can lead to geological disasters on the Loess Plateau in China.However,the spatiotemporal characteristics of infiltration in intact loess,parti...Water infiltration in loess is one of the most significant processes that can lead to geological disasters on the Loess Plateau in China.However,the spatiotemporal characteristics of infiltration in intact loess,particularly the heterogeneity of three-dimensional(3D)seepage and its relationship with soil properties,remain poorly understood.This study conducted field infiltration tests on a 3 m×3 m loess column,instrumented with 48 moisture sensors to monitor 3D seepage and infiltration rates.Both horizontal and vertical infiltration behaviors were analyzed,alongside a detailed characterization of soil physical properties.The results demonstrated that the water infiltration process was significantly heterogeneous in intact loess,with wetting front velocities varying considerably across profiles and depths,despite relatively uniform physical properties.The infiltration process also exhibited pronounced anisotropy,with vertical wetting front velocities at least 10 times higher than those of the horizontal velocities.The in situ tests indicated that the physical properties were not the primary factors influencing infiltration.However,the microfeatures that facilitated the formation of preferential pathways exerted the most significant influence on the water infiltration process in thick unsaturated loess.Additionally,prior infiltration events negatively impacted subsequent infiltration in thick unsaturated loess.These findings enhance the understanding of loess infiltration dynamics,providing insights into unsaturated flow processes and their implications for geological stability in loess regions.展开更多
Grouting with water–cement mixtures is the most widely used and cost-effective method for managing excess water inflow during tunnel construction.Due to uncertain geological and hydrological conditions,current grouti...Grouting with water–cement mixtures is the most widely used and cost-effective method for managing excess water inflow during tunnel construction.Due to uncertain geological and hydrological conditions,current grouting design relies heavily on the experience of onsite engineers.Recent advances in machine learning offer a promising alternative to traditional design to predict grout volume and improve grouting efficiency.Here,an artificial neural network(ANN)model was developed using the data set from an operation tunnel of Jurong Rock Caverns in Singapore to showcase an efficient and physics-guided training strategy.The ANN model was refined by incorporating the spatial scenarios,including the number of grouting holes in four quadrants of tunneling faces,the sequence of grouting screens along the tunnel axis,and the order of grouting rounds on the tunneling faces.The results indicate that an improved training strategy should encompass the grouting process,from Round 1 with grouting holes uniformly distributed around the tunnel periphery,to Round 2 with grouting holes drilled midway between neighboring first-round holes,and to Round 3 with grouting holes determined by onsite engineers.This model,trained based on the order of grouting rounds,performs better than the other models,highlighting the importance of establishing machine learning models grounded in physical principles.The finding was verified by the data set from another operation tunnel and concluded with a perspective on future grouting research.展开更多
While conventional FISH and IHC methods struggle to decode complex tissue heterogeneity and comprehensive molecular diagnosis due to low-throughput spatial information,spatial omics technologies enable high-throughput...While conventional FISH and IHC methods struggle to decode complex tissue heterogeneity and comprehensive molecular diagnosis due to low-throughput spatial information,spatial omics technologies enable high-throughput molecular mapping across tissue microenvironments.These technologies are emerging as transformative tools in molecular diagnostics and medical research.By integrating histopathological morphology with spatial multi-omics profiling(genome,transcriptome,epigenome,and proteome),spatial omics technologies open an avenue for understanding disease progression,therapeutic resistance mechanisms,and precise diagnosis.It particularly enhances tumor microenvironment analysis by mapping immune cell distributions and functional states,which may greatly facilitate tumor molecular subtyping,prognostic assessment,and prediction of the radiotherapy and chemotherapy efficacy.Despite the substantial advancements in spatial omics,the translation of spatial omics into clinical applications remains challenging due to robustness,efficacy,clinical validation,and cost constraints.In this review,we summarize the current progress and prospects of spatial omics technologies,particularly in medical research and diagnostic applications.展开更多
文摘The spatialization of population of counties in China is significant. Firstly, we can gain the estimated values of population density adaptive to different kinds of regions. Secondly, we can integrate effectively population data with other data including natural resources, environment, society and economy, build 1km GRIDs of natural resources reserves per person, population density and other economic and environmental data, which are necessary to the national management and macro adjustment and control of natural resources and dynamic monitoring of population. In order to establish population information system serving national decision making, three steps ought to be followed:1) establishing complete geographical spatial data foundation infrastructure including the establishment of electric map of residence with high resolution using topographical map with large scale and high resolution satellite remote sensing data, the determination of attribute information of housing and office buildings, and creating complete set of attribute database and rapid data updating; 2) establishing complete census systems including improving the transformation efficiency from census data to digital database and strengthening the link of census database and geographical spatial database, meanwhile, the government should attach great importance to the establishment and integration of population migration database; 3) considering there is no GIS software specially serving the analysis and management of population data, a practical approach is to add special modules to present software system, which works as a bridge actualizing the digitization and spatialization of population geography research.
文摘By using the observation data of drought,storm and hail in Dalian in recent 30 years,the spatialization of major agriculture meteorological disasters were carried out by means of cokriging and plate smooth slice spline method.Based on the 1:250 000 geographical information data in Dalian City,major meteorological disasters were spatially analyzed by using ArcMap,and the thematic map overlaying disaster distribution and crop information was made.Taking the distribution of hail disaster and crop yield for example,the application of spatialization method of agriculture meteorological disasters was elaborated.The results could provide decision basis for the establishment of disaster prevention and reduction and the optimization of crop distribution in Dalian.
基金supported by the Special Scientific Research Fund of China Earthquake Administration(201308018-5,201108002)
文摘Population and housing grid data spatialization hased on 340 grid samples （ 1 kmx 1 kin） is used in- stead of regional statistical data to simulate the population and housing distribution data of Yunnan Province （ 1 km×1 kin） for rapid loss assessment ibr the Jinggu Ms6.6 earthquake. The resuhs indicate that the method reflects the actual population and housing distribution and that the assessment results are eredihle. The method can be used to quickly provide spatial orientation disaster information after an earthquake.
文摘Recently,the expertise accumulated in the field of geovisualization has found application in the visualization of abstract multidimensional data,on the basis of methods called spatialization methods.Spatialization methods aim at visualizing multidimensional data into low-dimensional representational spaces by making use of spatial metaphors and applying dimension reduction techniques.Spatial metaphors are able to provide a metaphoric framework for the visualization of information at different levels of granularity.The present paper makes an investigation on how the issue of granularity is handled in the context of representative examples of spatialization methods.Furthermore,this paper introduces the prototyping tool Geo-Scape,which provides an interactive spatialization environment for representing and exploring multidimensional data at different levels of granularity,by making use of a kernel density estimation technique and on the landscape "smoothness" metaphor.A demonstration scenario is presented next to show how Geo-Scape helps to discover knowledge into a large set of data,by grouping them into meaningful clusters on the basis of a similarity measure and organizing them at different levels of granularity.
基金Project 40301042 supported by Natural Science Foundation of China
文摘In this paper the application of spatialization technology on metadata quality check and updating was dis-cussed. A new method based on spatialization was proposed for checking and updating metadata to overcome the defi-ciency of text based methods with the powerful functions of spatial query and analysis provided by GIS software. Thismethod employs the technology of spatialization to transform metadata into a coordinate space and the functions ofspatial analysis in GIS to check and update spatial metadata in a visual environment. The basic principle and technicalflow of this method were explained in detail, and an example of implementation using ArcMap of GIS software wasillustrated with a metadata set of digital raster maps. The result shows the new method with the support of interactionof graph and text is much more intuitive and convenient than the ordinary text based method, and can fully utilize thefunctions of GIS spatial query and analysis with more accuracy and efficiency.
基金National Natural Science Foundation of China[Grant Nos.42090010,U20A2091,41971349,and 41930107]National Key R&D Program of China[Grant Nos.2018YFC0809800 and 2017YFB0503704].
文摘Population spatialization is widely used for spatially downscaling census population data to finer-scale.The core idea of modern population spatialization is to establish the association between ancillary data and population at the administrative-unit-level(AUlevel)and transfer it to generate the gridded population.However,the statistical characteristic of attributes at the pixel-level differs from that at the AU-level,thus leading to prediction bias via the cross-scale modeling(i.e.scale mismatch problem).In addition,integrating multi-source data simply as covariates may underutilize spatial semantics,and lead to incorrect population disaggregation;while neglecting the spatial autocorrelation of population generates excessively heterogeneous population distribution that contradicts to real-world situation.To address the scale mismatch in downscaling,this paper proposes a Cross-Scale Feature Construction(CSFC)method.More specifically,by grading pixel-level attributes,we construct the feature vector of pixel grade proportions to narrow the scale differences in feature representation between AU-level and pixel-level.Meanwhile,fine-grained building patch and mobile positioning data are utilized to adjust the population weighting layer generated from POI-density-based regression modeling.Spatial filtering is furtherly adopted to model the spatial autocorrelation effect of population and reduce the heterogeneity in population caused by pixel-level attribute discretization.Through the comparison with traditional feature construction method and the ablation experiments,the results demonstrate significant accuracy improvements in population spatialization and verify the effectiveness of weight correction steps.Furthermore,accuracy comparisons with WorldPop and GPW datasets quantitatively illustrate the advantages of the proposed method in fine-scale population spatialization.
文摘基于国际比较的地方空间规划的范围和工具研究An International Comparison of the Scope and Instruments of Local Spatial Planning源自:The TownPlanning Review,2024,95(2):197-217作者:MaciejJNowak,StefanieDühr,Sergio Peña,et al.推荐:申明锐,南京大学建筑与城市规划学院。shenmingr@nju.edu.cn.
文摘针对UAV在仿真实验中自动跟踪移动目标的需求,提出基于改进CSRT(channel and spatial reliability-aware tracker)算法的无人机长时自动跟踪方法。通过导向滤波加拉普拉斯算子LOGF(laplacian of guided filter)检测获取目标边缘特征,再与HOG(histogram of oriented gradient)和CN(color names)特征融合,增强算法对目标的判别能力;使用平均峰值相关能量和感知哈希汉明距离来综合判定目标状态,当判定目标被遮挡时,采用YOLOv8定位目标,再将定位结果传输至跟踪算法继续跟踪目标。仿真结果表明:在搭建的仿真环境中算法能够在目标被遮挡时仍能长时稳定的跟踪目标,为无人机目标跟踪算法研究提供了良好的仿真实验环境。
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0530000)the Discipline Construction Foundation of“Double World-class Project”.
文摘Laser wakefield accelerators(LWFAs)offer acceleration gradients up to 1000 times higher than those of conventional radio-frequency accelerators,offering a pathway to significantly more compact and cost-effective accelerator systems.This breakthrough opens up new possibilities for laboratory-scale light sources.All-optical inverse Compton scattering(AOCS)sources driven by LWFAs produce high-brightness,quasimonochromatic X rays with micrometer-scale source sizes,delivering the spatial coherence and resolution required for X-ray phase-contrast imaging(XPCI).These features position AOCS X-ray sources as promising tools for applications in biology,medicine,physics,and materials science.However,previous AOCS-based imaging studies have primarily focused on X-ray absorption imaging.In this work,we report successful experimental demonstrations of edge-enhanced in-line XPCI using energy-tunable,quasi-monochromatic AOCS X rays.With a spatial resolution of~20μm,our results clearly show the potential of high-resolution,AOCS-based XPCI applications.
基金Under the auspices of the National Natural Science Foundation of China(No.42371222,41971167)Fundamental Scientific Research Funds of Central China Normal University(No.CCNU24ZZ120)。
文摘Owing to intensified globalization and informatization,the structures of the urban scale hierarchy and urban networks between cities have become increasingly intertwined,resulting in different spatial effects.Therefore,this paper analyzes the spatial interaction between urban scale hierarchy and urban networks in China from 2019 to 2023,drawing on Baidu migration data and employing a spatial simultaneous equation model.The results reveal a significant positive spatial correlation between cities with higher hierarchy and those with greater network centrality.Within a static framework,we identify a positive interaction between urban scale hierarchy and urban network centrality,while their spatial cross-effects manifest as negative neighborhood interactions based on geographical distance and positive cross-scale interactions shaped by network connections.Within a dynamic framework,changes in urban scale hierarchy and urban networks are mutually reinforcing,thereby widening disparities within the urban hierarchy.Furthermore,an increase in a city’s network centrality had a dampening effect on the population growth of neighboring cities and network-connected cities.This study enhances understanding of the spatial organisation of urban systems and offers insights for coordinated regional development.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.12074399,12204500,and 12004403)the Key Projects of Intergovernmental International Scientific and Technological Innovation Cooperation(No.2021YFE0116700)+1 种基金the Shanghai Natural Science Foundation(No.20ZR1464400)the Shanghai Sailing Program(No.22YF1455300).
文摘The suppression of ablative Rayleigh–Taylor instability(ARTI)by a spatially modulated laser in inertial confinement fusion(ICF)is studied through numerical simulations.The results show that in the acceleration phase of ICF implosion,the growth of ARTI can be suppressed by using a short-wavelength spatially modulated laser.The ARTI growth rate decreases as the wavelength of the spatially modulated laser decreases,and ARTI is completely suppressed after a certain wavelength has been reached.A spatially uniform laser is introduced to keep the state of motion of the implosion fluid consistent,and it is found that the proportion of the spatially modulated laser required for complete suppression of ARTI decreases as the wavelength continues to decrease.We also optimize the spatial intensity distribution of the spatially modulated laser.In addition,as the duration of the spatially modulated laser decreases,the proportion required for completely suppressing ARTI increases,but the required energy decreases.When the perturbation wavenumber decreases,the wavelength of the spatially modulated laser required for complete suppression of ARTI becomes longer.In the case of multimode perturbation,ARTI can also be significantly suppressed by a spatially modulated laser,and the perturbation amplitude can be reduced to less than 10% of that without a spatially modulated laser.We believe that the conclusions drawn from our simulations can provide the basis for new approaches to control ARTI in ICF.
文摘Alzheimer’s disease(AD)is the most common form of dementia.In addition to the lack of effective treatments,there are limitations in diagnostic capabilities.The complexity of AD itself,together with a variety of other diseases often observed in a patient’s history in addition to their AD diagnosis,make deciphering the molecular mechanisms that underlie AD,even more important.Large datasets of single-cell RNA sequencing,single-nucleus RNA-sequencing(snRNA-seq),and spatial transcriptomics(ST)have become essential in guiding and supporting new investigations into the cellular and regional susceptibility of AD.However,with unique technology,software,and larger databases emerging;a lack of integration of these data can contribute to ineffective use of valuable knowledge.Importantly,there was no specialized database that concentrates on ST in AD that offers comprehensive differential analyses under various conditions,such as sex-specific,region-specific,and comparisons between AD and control groups until the new Single-cell and Spatial RNA-seq databasE for Alzheimer’s Disease(ssREAD)database(Wang et al.,2024)was introduced to meet the scientific community’s growing demand for comprehensive,integrated,and accessible data analysis.
基金supported by the National Natural Science Foundation of China[Grant No.72373084]Taishan Scholar Foundation of Shandong Province[Grant No.tsqn202408139].
文摘Investigating urban spatial structures(USSs)and their influencing factors at different spatial scales is crucial for promoting sustainable urban transformation.Based on nighttime light datasets and the Herfindahl-Hirschman index(HHI),this study analyzes USS characteristics in China from 2007 to 2023 on two spatial scales-prefecture-level cities and urban agglomerations.It also explores structural influencing factors,including the economy,infrastructure,society,and government intervention.We find that:(1)HHI values for both cities and urban agglomerations exhibit a decreasing trend,indicating a USS for both that is evolving toward polycentricity;(2)economic development promotes a polycentric structure at both spatial scales,whereas government intervention drives a monocentric structure;and(3)postal and communication infrastructure have conflicting effects on USSs,encouraging a monocentric structure at the city scale but fostering polycentricity at the urban agglomeration scale.
基金supported by the National Natural Science Foundation of China[grant number 12001266]the Humanities and Social Science Projects ofMinistry of Education of China[grant number 19YJCZH166]supported by the National Natural Science Foundation of China[grant numbers 12271168 and 12531013].
文摘The integrated nested Laplace approximation(INLA)algorithm provides a computationally efficient approach for approximate Bayesian inference,overcoming the limitations of traditional Markov chain Monte Carlo(MCMC)methods.This paper reviews INLA algorithm and provides a systematic review of six key books that explore the theoretical foundations,practical implementations,and diverse applications of INLA.These six books cover spatial and spatio-temporal modelling,general Bayesian inference,SPDE-based spatial analysis,geospatial health data,regression modelling,and dynamic time series.In addition,these books highlight the versatility of INLA method in handling complex models while maintaining high computational efficiency.This paper begins with an introduction to the INLA method and algorithm,followed by a systematic review of six key publications in the field.
基金supported by the National Nature Science Foundation of China(No.52402126)Shaanxi Province Qin Chuangyuan general window four chain integration project(No.2024PT-ZCK-09)+3 种基金Shaanxi Province military-civilian integration project(Shaanxi finance office【2024】22nd)Qinchuangyuan introducing high-level innovation and entrepreneurship talent projects(NO.QCYRCXM-2022-343)the China Postdoctoral Science Foundation(Grant Number:2025M772524)National Nature Science Foundation of China(22508239).
文摘Two-dimensional materials for flexible energy storage commonly facehuge challenges in limited active surface and hindered charge transport.Herein,wereport an innovative asymmetric pseudocapacitor based on synergistic design of modifiedMXene and graphene,integrating gas-induced rapid expansion technology andprecise surface chemical regulation methods.For graphene modification,rapid vaporizationinduces exfoliation and expansion of graphene oxide layers.Subsequently,pseudocapacitiveoxygen-containing groups were selectively introduced through acid oxidation,yielding expanded-and-oxidized graphene(OEG)for positive porous-nanopaperelectrode.For MXene modification,alkali-treated MXene underwent hydrazine assistance to facilitate gas expansion and-NH_(2)grafting,producing MXene-NH_(2)(NOM)for negative porous-nanopaper electrode.Density functional theory calculations show that-COOH moreeffectively modulate graphene’s electronic structure by inducing charge redistribution and creating active sites,thereby enhancing H^(+)adsorption and ion interactions compared to-OH.Meanwhile,-NH_(2)on MXene enable electron delocalization and dynamic Ti-N-H^(+)interactions,speeding up proton adsorption/desorption and boosting both pseudocapacitance and conductivity.Through collaborativeoptimized spatial architecture and surface properties,flexible OEGB and NOMB exhibited of 333.6 and 500.5 F g^(-1)at high mass loading,respectively.The assembled proton pseudocapacitor readily achieved energy and power densities of 58.9 Wh kg^(-1)and 3802 W kg^(-1),respectively,with excellent stability for potential applications.
基金support from the European Research Council(ERC)under the European Union’s Horizon 2020 research and innovation programme(Grant agreement No.819202)the Research Council of Finland’s Flagship Programme and Doctoral Education Pilot under project Digital Waters(Grant No.359248)funded by the Research Council of Finland's Flagship ProgrammeStrategic Research Council(SRC)through project‘Water&Food’(Grant No.365512).
文摘Endowed with opportunities from both land and ocean,coastal areas attract expanding human populations and economic activities.At the same time,they face growing societal and environmental pressures from both the above river catchments and the bordering sea due to climate change,ecosystem degradation,and expansion of built-up areas.Despite the accumulation of human population,economic activities,and environmental impacts,we lack social-ecological systems analysis on water-related risks to world’s coastal human population.To address this research gap,we analyze the spatial extent of six globally important water stressors to people within the world’s coastal zone(100 km from the coastal line)and classify this zone globally into 12 groups by distance from the coastline and elevation from the mean sea level.Adopting the approaches of the UN Sendai Framework and IPCC,we produce risk maps from the stressor maps by multiplying them with population exposure and vulnerability.For most risks,geographical hotspots are the Chinese coast,Bay of Bengal,Gujarat,and the Island of Java.The analysis reveals fundamental differences between water stressors and related risks,often mixed in scholarly literature.Both manifest specific geographic patterns and latitudinal profiles.Our study highlights the importance of high-resolution spatial analysis of vulnerability,exposure,and risks posed by water related stressors in the world’s coastal zone,in a manner prompted by key policy bodies to promote policy design and shared responsibility for managing stress-prone areas.
基金supported by the National Natural Science Foundation of China(Grant No.42372307)the Natural Science Basic Research Program of Shaanxi Province(Grant No.2020JC-07)the SCEGC-XJTU Joint Research Center for Future City Construction and Management Innovation,Shaanxi Provincial Land Engineering Construction Group,and Xi’an Jiaotong University(Grant No.20221220).
文摘Water infiltration in loess is one of the most significant processes that can lead to geological disasters on the Loess Plateau in China.However,the spatiotemporal characteristics of infiltration in intact loess,particularly the heterogeneity of three-dimensional(3D)seepage and its relationship with soil properties,remain poorly understood.This study conducted field infiltration tests on a 3 m×3 m loess column,instrumented with 48 moisture sensors to monitor 3D seepage and infiltration rates.Both horizontal and vertical infiltration behaviors were analyzed,alongside a detailed characterization of soil physical properties.The results demonstrated that the water infiltration process was significantly heterogeneous in intact loess,with wetting front velocities varying considerably across profiles and depths,despite relatively uniform physical properties.The infiltration process also exhibited pronounced anisotropy,with vertical wetting front velocities at least 10 times higher than those of the horizontal velocities.The in situ tests indicated that the physical properties were not the primary factors influencing infiltration.However,the microfeatures that facilitated the formation of preferential pathways exerted the most significant influence on the water infiltration process in thick unsaturated loess.Additionally,prior infiltration events negatively impacted subsequent infiltration in thick unsaturated loess.These findings enhance the understanding of loess infiltration dynamics,providing insights into unsaturated flow processes and their implications for geological stability in loess regions.
基金Ministry of Education-Singapore,Grant/Award Number:RG143/23。
文摘Grouting with water–cement mixtures is the most widely used and cost-effective method for managing excess water inflow during tunnel construction.Due to uncertain geological and hydrological conditions,current grouting design relies heavily on the experience of onsite engineers.Recent advances in machine learning offer a promising alternative to traditional design to predict grout volume and improve grouting efficiency.Here,an artificial neural network(ANN)model was developed using the data set from an operation tunnel of Jurong Rock Caverns in Singapore to showcase an efficient and physics-guided training strategy.The ANN model was refined by incorporating the spatial scenarios,including the number of grouting holes in four quadrants of tunneling faces,the sequence of grouting screens along the tunnel axis,and the order of grouting rounds on the tunneling faces.The results indicate that an improved training strategy should encompass the grouting process,from Round 1 with grouting holes uniformly distributed around the tunnel periphery,to Round 2 with grouting holes drilled midway between neighboring first-round holes,and to Round 3 with grouting holes determined by onsite engineers.This model,trained based on the order of grouting rounds,performs better than the other models,highlighting the importance of establishing machine learning models grounded in physical principles.The finding was verified by the data set from another operation tunnel and concluded with a perspective on future grouting research.
基金supported by the National Natural Science Foundation of China(32171022,32221005,and 32401246).
文摘While conventional FISH and IHC methods struggle to decode complex tissue heterogeneity and comprehensive molecular diagnosis due to low-throughput spatial information,spatial omics technologies enable high-throughput molecular mapping across tissue microenvironments.These technologies are emerging as transformative tools in molecular diagnostics and medical research.By integrating histopathological morphology with spatial multi-omics profiling(genome,transcriptome,epigenome,and proteome),spatial omics technologies open an avenue for understanding disease progression,therapeutic resistance mechanisms,and precise diagnosis.It particularly enhances tumor microenvironment analysis by mapping immune cell distributions and functional states,which may greatly facilitate tumor molecular subtyping,prognostic assessment,and prediction of the radiotherapy and chemotherapy efficacy.Despite the substantial advancements in spatial omics,the translation of spatial omics into clinical applications remains challenging due to robustness,efficacy,clinical validation,and cost constraints.In this review,we summarize the current progress and prospects of spatial omics technologies,particularly in medical research and diagnostic applications.
