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Spatial-temporal Distribution Characteristics of Global Seismic Clusters and Associated Spatial Factors 预览
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作者 YANG Jing CHENG Changxiu +3 位作者 SONG Changqing SHEN Shi ZHANG Ting NING Lixin 《中国地理科学:英文版》 SCIE CSCD 2019年第4期614-625,共12页
Earthquakes exhibit clear clustering on the earth. It is important to explore the spatial-temporal characteristics of seismicity clusters and their spatial heterogeneity. We analyze effects of plate space, tectonic st... Earthquakes exhibit clear clustering on the earth. It is important to explore the spatial-temporal characteristics of seismicity clusters and their spatial heterogeneity. We analyze effects of plate space, tectonic style, and their interaction on characteristic of cluster.Based on data of earthquakes not less than moment magnitude(M_w) 5.6 from 1960 to 2014, this study used the spatial-temporal scan method to identify earthquake clusters. The results indicate that seismic spatial-temporal clusters can be classified into two types based on duration: persistent clusters and burst clusters. Finally, we analysed the spatial heterogeneity of the two types. The main conclusions are as follows: 1) Ninety percent of the persistent clusters last for 22-38 yr and show a high clustering likelihood;ninety percent of the burst clusters last for 1-1.78 yr and show a high relative risk. 2) The persistent clusters are mainly distributed in interplate zones, especially along the western margin of the Pacific Ocean. The burst clusters are distributed in both intraplate and interplate zones, slightly concentrated in the India-Eurasia interaction zone. 3) For the persistent type, plate interaction plays an important role in the distribution of the clusters’ likelihood and relative risk. In addition, the tectonic style further enhances the spatial heterogeneity. 4) For the burst type,neither plate activity nor tectonic style has an obvious effect on the distribution of the clusters’ likelihood and relative risk. Nevertheless,interaction between these two spatial factors enhances the spatial heterogeneity, especially in terms of relative risk. 展开更多
关键词 GLOBAL earthquake spatial-temporal cluster duration SPATIAL HETEROGENEITY plate SPACE tectonic style INTERSECTION SPACE
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20世纪90年代以来世界能源安全时空格局演化过程(英文)
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作者 王强 徐玲琳 +4 位作者 李娜 杜雪 伍世代 田兰蓝 吴琛璐 《地理学报:英文版》 SCIE CSCD 2019年第8期1245-1260,共16页
In this study, we developed an energy security evaluation model(ESEM) from three dimensions, energy supply-transport security, safety of energy utilization, and stability of political-socioeconomic environment, based ... In this study, we developed an energy security evaluation model(ESEM) from three dimensions, energy supply-transport security, safety of energy utilization, and stability of political-socioeconomic environment, based on the integrated application of subjective and objective weight allocation technique. Then the spatial-temporal evolution of global energy security pattern and its driving mechanism was analyzed with the method above, and the results are shown as follows:(1) since the 1990 s, the spatial patterns of global energy security have shown a deteriorating trend, with the growth of countries in at-risk type and relatively at-risk type.(2) The spatial distribution of countries with secure energy system shows a strong stability, and these countries are concentrated persistently in Western Europe and North America. The spatial evolution of countries with relatively secure energy system also presents a strong stability, which are mainly distributed in the periphery of the secure ones, namely Central and Southern Europe, South America and Eurasia, while countries with general energy system are mainly distributed in Asia, Africa and Southern Europe, and the spatial-temporal evolution of this type is the main cause for the deterioration of world energy security pattern. Countries with at-risk and relatively at-risk energy system are mainly concentrated in Africa, Asia, the Middle East and Eurasia, rendering spatial extension to the east and south.(3) In the past 20 years, the mechanism for world’s energy security pattern formation gradually transforms from the ‘unitary dimension dominated’ to the ‘binary dimension-dominated’, and the main factors influencing the global energy security pattern become more diverse.(4) In the pattern of world’s energy security, China’s performance on energy security has been the global average since the 1990 s, which shows a decreasing trend in safety of energy utilization dimension. Findings in this study can provide a reference for the government in terms of formulati 展开更多
关键词 ENERGY SECURITY spatial-temporal EVOLUTION subjective-objective WEIGHT ALLOCATION method the globe
区域PM2.5时空建模与分析研究--以福建省为例 预览
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作者 覃杰 蔡周旸 杨勇 《环境科学与管理》 CAS 2019年第5期47-51,共5页
深入理解区域PM2.5时空分布及演变状况是进行大气环境治理的基础。以福建省2016年PM2.5日监测数据为基础,计算了不同滞后距级别的试验时空变异函数,并拟合了理论时空变异模型。在此基础上,利用时空克里格方法对区域PM2.5浓度进行了使用... 深入理解区域PM2.5时空分布及演变状况是进行大气环境治理的基础。以福建省2016年PM2.5日监测数据为基础,计算了不同滞后距级别的试验时空变异函数,并拟合了理论时空变异模型。在此基础上,利用时空克里格方法对区域PM2.5浓度进行了使用内插,获得了PM2.5时空立方体数据。基于该数据,对福建省2016年PM2.5进行了时空分析,结果表明,福建省PM2.5在空间上呈现南高北低的地带性趋势,时间上呈现冬春高、夏秋低的趋势。 展开更多
关键词 PM2.5 时空 福建
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Spatio-temporal Pattern Characteristics of Relationship Between Urbanization and Economic Development at County Level in China 预览
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作者 YANG Zhen ZHANG Xiaolei +2 位作者 LEI Jun DUAN Zuliang LI Jiangang 《中国地理科学:英文版》 SCIE CSCD 2019年第4期553-567,共15页
The relationship between China’s urbanization and economic development(RCUED) is an important concern nationwide. As important actors in regional strategy and policy, county-level regions have played an increasingly ... The relationship between China’s urbanization and economic development(RCUED) is an important concern nationwide. As important actors in regional strategy and policy, county-level regions have played an increasingly significant role in the development of China’s social economy. However, the existing research on the RCUED lacks the fine depiction of the county-level administrative units.Using 2000 and 2010 census data and the statistical analysis method, we uncovered the evolution characteristics of China’s urbanization and economic development and conducted a quantitative identification for the RCUED with improved methods using the quadrant map approach. In addition, we investigated the spatial correlation effect of the RCUED using the spatial autocorrelation analysis method. The results were as follows: 1) In general, a high degree of matching exists between China’s urbanization and economic development at the county level at the significance level of 0.01. The correlation coefficients between China’s urbanization and economic development in2000 and 2010 were 0.608 and 0.603, respectively. 2) A significant regional difference exists in the RCUED at the county level. Based on a comparative analysis of 2276 county units in China in the two years, we found that county units can be categorized as under-urbanized, basic coordination and over-urbanized in various areas. No situation was observed where urbanization seriously lagged behind the economic development level, so the levels of urbanization and economic development appear to be basically coordinated,and the coordination state may be gradually optimized over time. 3) Over time, the spatial dependency of the RCUED has weakened and the spatial heterogeneity has increased. Northeast China has always been an area characterized by over-urbanization. The number of county units classified as under-urbanized has begun to decline in eastern coastal urban agglomeration areas, while counties rich in resources have transformed from having point-shaped over-urbani 展开更多
关键词 URBANIZATION ECONOMIC development RELATIONSHIP spatial-temporal PATTERN COUNTY China
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Global precision analysis of carrier phase relative positioning in BeiDou navigation satellite system and United States global positioning system
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作者 Letao ZHOU Dingfa HUANG +3 位作者 Wei FENG Wu CHEN Xi ZHANG Li YAN 《中国科学:地球科学英文版》 SCIE EI CAS CSCD 2019年第4期733-749,共17页
In this paper, we derived a high-efficiency formula for calculating the precision of carrier phase relative positioning,analyzed the various factors that affect the positioning accuracy using the carrier phase, and pr... In this paper, we derived a high-efficiency formula for calculating the precision of carrier phase relative positioning,analyzed the various factors that affect the positioning accuracy using the carrier phase, and proposed the concept of using a frequency dilution of precision to describe the quantitative effect of different frequency combinations on the positioning precision. To this end, we computed and plotted the global spatial distribution map of the relative positioning dilution of precision for single-day solution, half-hour solution, and single-epoch solution of the global positioning system(GPS), regional Beidou navigation satellite system(BDS2), future global Beidou navigation satellite system(BDS3), and their fusion systems.Using processing software with autonomous intellectual property rights(GCN and VENUS/ARSNet), we solved the measurement data and examined the positioning precision of the single-day solution and single-epoch solution of GPS and BDS2.The analysis demonstrated that the B1/B2 frequency positioning precision of BDS2 was better than that of L1/L2 frequency positioning of GPS, but the positioning precision of the BDS2 is worse than that of GPS over most of the service region of the BDS2. Further, the positioning precision of BDS3 is better than that of GPS in the Asia-Pacific region, while it is the opposite in other regions. Based on these conclusions, we put forth some optimization recommendations regarding the signal frequency of the navigation system and GPS measurement standards to serve as references for optimizing the system performance and formulating standards. 展开更多
关键词 BEIDOU navigation satellite system RELATIVE POSITIONING DILUTION of PRECISION Frequency DILUTION of PRECISION Spatial-temporal AVAILABILITY
Spatial-temporal coupling between high-quality source rocks and reservoirs for tight sandstone oil and gas accumulations in the Songliao Basin,China 预览
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作者 Laixing Cai Guolin Xiao +2 位作者 Shuangfang Lu Jiao Wang Zhiqiang Wu 《矿业科学技术学报:英文版》 CSCD 2019年第3期387-397,共11页
The spatial-temporal relationship between high-quality source rocks and reservoirs is a key factor when evaluating the formation,occurrence,and prospectivity of tight oil and gas reservoirs.In this study,we analyze th... The spatial-temporal relationship between high-quality source rocks and reservoirs is a key factor when evaluating the formation,occurrence,and prospectivity of tight oil and gas reservoirs.In this study,we analyze the fundamental oil and gas accumulation processes occurring in the Songliao Basin,contrasting tight oil sand reservoirs in the south with tight gas sand reservoirs in the north.This is done using geochemical data,constant-rate and conventional mercury injection experiments,and fluid inclusion analyses.Our results demonstrate that as far as fluid mobility is concerned,the expulsion center coincides with the overpressure zone,and its boundary limits the occurrence of tight oil and gas accumulations.In addition,the lower permeability limit of high-quality reservoirs,controlled by pore-throat structures,is 0.1×10^-3μm^2 in the fourth member of the Lower Cretaceous Quantou Formation(K1q^4)in the southern Songliao Basin,and 0.05×10^-3μm^2 in the Lower Cretaceous Shahezi Formation(K1sh)in the northern Songliao Basin.Furthermore,the results indicate that the formation of tight oil and gas reservoirs requires the densification of reservoirs prior to the main phase of hydrocarbon expulsion from the source rocks.Reservoir“sweet spots”develop at the intersection of high-quality source rocks(with high pore pressure)and reservoirs(with high permeability). 展开更多
关键词 Spatial-temporal COUPLING HIGH-QUALITY source rock HIGH-QUALITY SANDSTONE TIGHT SANDSTONE reservoir Songliao Basin
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Spatial-temporal Patterns and Driving Forces of Water Retention Service in China 预览
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作者 XIAO Yang OUYANG Zhiyun 《中国地理科学:英文版》 SCIE CSCD 2019年第1期100-111,共12页
Overwhelming water-deficiency conditions and an unbalanced water supply and demand have been major concerns of both the Chinese government and the general public during recent decades. Studying the spatial-temporal pa... Overwhelming water-deficiency conditions and an unbalanced water supply and demand have been major concerns of both the Chinese government and the general public during recent decades. Studying the spatial-temporal patterns and impact factors that influence water retention in China is important to enhance the management of water resources in China and other similar countries. We employed a revised Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST) model and regression analyses to investigate the water retention service in China. The results showed that the southeastern China generally performed much better than Northwest China in terms of the spatial distribution of water retention. In general, the efficacy of the water retention service in China increased from 2000 to 2014;although some areas still had a downward trend. Water retention service increased significantly(P < 0.05) in aggregate in the Qinghai-Tibet Plateau, and the Da Hinggan Mountains and Xiao Hinggan Mountains. However, the service in southwestern China showed a decreasing trend(P < 0.05), which would have significant negative impact on the downstream population. This study also showed that in China the changes in water retention service were primarily due to climate change(which could explain 83.49% of the total variance), with anthropogenic impact as a secondary influence(likewise the ecological programs and socioeconomic development could explain 9.47% and 1.06%, respectively). Moreover, the identification of water retention importance indicated that important areas conservation and selection based on downstream beneficiaries is vital for optimization protection of ecosystem services, and has practical significance for natural resources and ecosystem management. 展开更多
关键词 WATER RETENTION spatial-temporal pattems driving FACTORS China
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Improving remote sensing-based net primary production estimation in the grazed land with defoliation formulation model
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作者 YE Hui HUANG Xiao-tao +3 位作者 LUO Ge-ping WANG Jun-bang ZHANG Miao WANG Xin-xin 《山地科学学报:英文版》 SCIE CSCD 2019年第2期323-336,共14页
Remote sensing(RS) technologies provide robust techniques for quantifying net primary productivity(NPP) which is a key component of ecosystem production management. Applying RS, the confounding effects of carbon consu... Remote sensing(RS) technologies provide robust techniques for quantifying net primary productivity(NPP) which is a key component of ecosystem production management. Applying RS, the confounding effects of carbon consumed by livestock grazing were neglected by previous studies, which created uncertainties and underestimation of NPP for the grazed lands. The grasslands in Xinjiang were selected as a case study to improve the RS based NPP estimation. A defoliation formulation model(DFM) based on RS is developed to evaluate the extent of underestimated NPP between 1982 and 2011. The estimates were then used to examine the spatiotemporal patterns of the calculated NPP. Results show that average annual underestimated NPP was 55.74 gC·m-2yr-1 over the time period understudied, accounting for 29.06% of the total NPP for the Xinjiang grasslands. The spatial distribution of underestimated NPP is related to both grazing intensity and time. Data for the Xinjiang grasslands show that the average annual NPP was 179.41 gC·m-2yr-1, the annual NPP with an increasing trend was observed at a rate of 1.04 gC·m-2yr-1 between 1982 and 2011. The spatial distribution of NPP reveals distinct variations from high to low encompassing the geolocations of the Tianshan Mountains, northern and southern Xinjiang Province and corresponding with mid-mountain meadow, typical grassland, desert grassland, alpine meadow, and saline meadow grassland types. This study contributes to improving RS-based NPP estimations for grazed land and provides a more accurate data to support the scientific management of fragile grassland ecosystems in Xinjiang. 展开更多
关键词 Remote SENSING DEFOLIATION FORMULATION model Net primary production Grazed LAND Spatial-temporal patterns XINJIANG
全球大气温度廓线的统计特性分析 预览
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作者 罗双 尹球 《热带气象学报》 CSCD 北大核心 2019年第4期556-566,共11页
利用欧洲数值预报中心发布的第三代ERA-Interim月平均再分析资料对1979—2016年全球大气温度廓线进行统计,分别探讨了南、北半球大气温度廓线平均值和标准差随季节、纬度和海陆的时空分布特征,并与国内外常用的AFGL标准大气廓线进行了... 利用欧洲数值预报中心发布的第三代ERA-Interim月平均再分析资料对1979—2016年全球大气温度廓线进行统计,分别探讨了南、北半球大气温度廓线平均值和标准差随季节、纬度和海陆的时空分布特征,并与国内外常用的AFGL标准大气廓线进行了对比。研究结果表明:南、北半球各高度层温度的平均值、频数最大温度区间和最大值垂直分布均随高度先减小后增加;在大气低层,多年的温度波动较大,200hPa处波动达到最小;不论是北半球还是南半球,大气温度平均值廓线均具有典型的纬度差异,其中低纬度季节性差异较小,中纬度次之,高纬季节性差异最大;各季节大气温度廓线的海陆差异不同,且南半球海陆差异比北半球大。大气温度标准差廓线同样存在纬度、海陆和季节分布差异。根据ECMWF再分析资料构建的温度廓线较AFGL标准大气廓线而言具有更加丰富的时空分布等细节特征,并且代表了气候变化后最新的大气温度状况。有关结果可作为现有标准大气廓线的更新和完善,为新型卫星仪器应用性能评估、辐射传输算法和大气反演方法评价和对比分析提供支持。 展开更多
关键词 ERA-INTERIM 垂直廓线 时空分布 温度
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Spatial-temporal Analysis of Daily Air Quality Index in the Yangtze River Delta Region of China During 2014 and 2016 预览
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作者 YE Lei OU Xiangjun 《中国地理科学:英文版》 SCIE CSCD 2019年第3期382-393,共12页
Urban air pollution is a prominent problem related to the urban development in China, especially in the densely populated urban agglomerations. Therefore, scientific examination of regional variation of air quality an... Urban air pollution is a prominent problem related to the urban development in China, especially in the densely populated urban agglomerations. Therefore, scientific examination of regional variation of air quality and its dominant factors is of great importance to regional environmental management. In contrast to traditional air pollution researches which only concentrate on a single year or a single pollutant, this paper analyses spatiotemporal patterns and determinants of air quality in disparate regions based on the air quality index(AQI) of the Yangtze River Delta region(YRD) of China from 2014 to 2016. Results show that the annual average value of the AQI in the YRD region decreases from 2014 to 2016 and exhibit a basic characteristic of ‘higher in winter, lower in summer and slightly high in spring and autumn’. The attainment rate of the AQI shows an apparently spatial stratified heterogeneity, Hefei metropolitan area and Nanjing metropolitan area keeping the worst air quality. The frequency of air pollution occurring in large regions was gradually decreasing during the study period. Drawing from entropy method analysis, industrialization and urbanization represented by per capita GDP and total energy consumption were the most important factors. Furthermore, population agglomeration is a factor that cannot be ignored especially in some mega-cities. Limited to data collection, more research is needed to gain insight into the spatiotemporal pattern and influence mechanism in the future. 展开更多
关键词 air quality index(AQI) spatial-temporal evolution contributing FACTORS YANGTZE RIVER Delta(YRD)
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八宝河流域土壤温度波动的时空分异
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作者 宁立新 程昌秀 沈石 《地理学报:英文版》 SCIE CSCD 2019年第9期1475-1490,共16页
The Babao River Basin is the "water tower" of the Heihe River Basin.The combination of vulnerable ecosystems and inhospitable natural environments substantially restricts the existence of humans and the sust... The Babao River Basin is the "water tower" of the Heihe River Basin.The combination of vulnerable ecosystems and inhospitable natural environments substantially restricts the existence of humans and the sustainable development of society and environment in the Heihe River Basin.Soil temperature(ST) is a critical soil variable that could affect a series of physical,chemical and biological soil processes,which is the guarantee of water conservation and vegetation growth in this region.To measure the temporal variation and spatial pattern of ST fluctuation in the Babao River Basin,fluctuation of ST at various depths were analyzed with ST data at depths of 4,10 and 20 cm using classical statistical methods and permutation entropy.The study results show the following: 1) There are variations of ST at different depths,although ST followed an obvious seasonal law.ST at shallower depths is higher than at deeper depths in summer,and vice versa in winter.The difference of ST between different depths is close to zero when ST is near 5℃ in March or –5℃ in September.2) In spring,ST at the shallower depths becomes higher than at deeper depths as soon as ST is above –5℃;this is reversed in autumn when ST is below 5℃.ST at a soil depth of 4 cm is the first to change,followed by ST at 10 and 20 cm,and the time that ST reaches the same level is delayed for 10–15 days.In chilling and warming seasons,September and February are,respectively,the months when ST at various depths are similar.3) The average PE values of ST for 17 sites at 4 cm are 0.765 in spring > 0.764 in summer > 0.735 in autumn > 0.723 in winter,which implies the complicated degree of fluctuations of ST.4) For the variation of ST at different depths,it appears that Max,Ranges,Average and the Standard Deviation of ST decrease by depth increments in soil.Surface soil is more complicated because ST fluctuation at shallower depths is more pronounced and random.The average PE value of ST for 17sites are 0.863 at a depth of 4 cm > 0.818 at 10 cm > 0.744 at 20 展开更多
关键词 soil temperature spatial-temporal FLUCTUATION CLASSICAL STATISTICAL methods PERMUTATION ENTROPY Babao River Basin
海南植被净初级生产力时空分布特征研究 预览
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作者 刘少军 李伟光 +1 位作者 陈小敏 佟金鹤 《生态科学》 CSCD 2019年第5期52-57,共6页
海南是一个相对独立地理单元,生态环境优越,植被NPP是判定生态系统健康状况和可持续发展水平的重要指标。基于2000—2015年海南省MODIS NPP数据集,采用趋势线分析法和相关分析法对海南被净初级生产力时空分布特征研究。结果表明:(1)2000... 海南是一个相对独立地理单元,生态环境优越,植被NPP是判定生态系统健康状况和可持续发展水平的重要指标。基于2000—2015年海南省MODIS NPP数据集,采用趋势线分析法和相关分析法对海南被净初级生产力时空分布特征研究。结果表明:(1)2000—2015年海南省植被净初级生产力(NPP)呈现整体微弱的上升趋势,植被年平均NPP变化范围为794.5—998.3 gC·m^-2,年平均值886.2 gC·m^-2。(2)从空间分布看,海南2000—2015年平均NPP分布呈现中高四周低的趋势,其中年平均NPP>1000 gC·m^-2主要分布在海南的中部山区,年平均NPP<600 gC·m^-2区域主要分布在海南的西部和北部的海岸带附近。(3)其中气候变化和人类活动是NPP变化的主要驱动因素,但在不同区域影响的因子的影响程度存在差异。以上研究可为海南生态环境保护和评估提供参考。 展开更多
关键词 植被 净初级生产力 时空分布 海南
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2004~2013年安徽省县域畜禽养殖环境风险时空特征及调控规划
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作者 阎波杰 史文娇 于海玲 《地球与环境》 CAS CSCD 北大核心 2019年第2期202-210,共9页
为掌握安徽省近十年来畜禽养殖业对生态环境的潜在污染影响,本文基于2004~2013年安徽省县域畜禽养殖统计数据及耕地数据,以耕地畜禽粪便氮、磷负荷为评价指标,对安徽省县域畜禽养殖环境风险时空特征进行评估,并对高环境风险县市区进行... 为掌握安徽省近十年来畜禽养殖业对生态环境的潜在污染影响,本文基于2004~2013年安徽省县域畜禽养殖统计数据及耕地数据,以耕地畜禽粪便氮、磷负荷为评价指标,对安徽省县域畜禽养殖环境风险时空特征进行评估,并对高环境风险县市区进行调控规划研究。结果表明,安徽省各县市区的耕地畜禽粪便氮、磷负荷结果相互之间差异较大;2004~2013年安徽省大部分区域都属于无环境风险区域,高环境风险区域主要集中在合肥市的市辖区、肥西县、长丰县等县市区,低环境风险区域主要集中在灵璧县、全椒县等县市区;十年间存在环境风险的县市区数量以2005年最多,为28个;其次是2006和2013年,为26个;数量最少的年份是2007年,为11个;安庆市太湖县、合肥市长丰县、宣州市广德县等6个县市区的畜禽粪便能在其所属地级市的范围内进行畜禽养殖产业转移消化,以达到减排的目的。宿州市砀山县、蚌埠市固镇县、六安市寿县等5个县市区的畜禽粪便中的氮也能进行畜禽养殖产业转移实现消化减排,但部分磷无法通过产业转移实现消化减排。研究结果可为该省畜禽养殖业持续健康发展提供科学依据。 展开更多
关键词 畜禽养殖 负荷 环境风险 时空
空间社会学视角下虚拟空间系统的空间性与时间性 预览
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作者 刘秀清 管其平 《淄博师专论丛》 2019年第2期74-76,共3页
社会系统是不同的社会行为模式与制度共同组成的空间制度化模式,空间社会学将系统分为实体的实在系统与虚拟的空间系统,社会系统产生于社会主体之间的行动关系,具有复杂性、流动性以及开放性等特征。空间与时间是社会主体进行空间行为... 社会系统是不同的社会行为模式与制度共同组成的空间制度化模式,空间社会学将系统分为实体的实在系统与虚拟的空间系统,社会系统产生于社会主体之间的行动关系,具有复杂性、流动性以及开放性等特征。空间与时间是社会主体进行空间行为的物质维度,空间性与时间性是社会动态变化中的体态性因素,先进大数据、虚拟系统的发展造成了空间与时间的置换。用空间来获取时间上的优势,用时间来谋取空间上的突破,时间与空间乃是空间社会学视角下虚拟空间系统的机制,分析这一机制对认识虚拟的空间系统具有重要的理论意义与指导意义。 展开更多
关键词 虚拟空间 空间性与时间性 时空分离
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Effective Crowd Anomaly Detection Through Spatio-temporal Texture Analysis
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作者 Yu Hao Zhi-Jie Xu +2 位作者 Ying Liu Jing Wang Jiu-Lun Fan 《国际自动化与计算杂志:英文版》 EI CSCD 2019年第1期27-39,共13页
Abnormal crowd behaviors in high density situations can pose great danger to public safety.Despite the extensive installation of closed-circuit television(CCTV)cameras,it is still difficult to achieve real-time alerts... Abnormal crowd behaviors in high density situations can pose great danger to public safety.Despite the extensive installation of closed-circuit television(CCTV)cameras,it is still difficult to achieve real-time alerts and automated responses from current systems.Two major breakthroughs have been reported in this research.Firstly,a spatial-temporal texture extraction algorithm is developed.This algorithm is able to effectively extract video textures with abundant crowd motion details.It is through adopting Gaborfiltered textures with the highest information entropy values.Secondly,a novel scheme for defining crowd motion patterns(signatures)is devised to identify abnormal behaviors in the crowd by employing an enhanced gray level co-occurrence matrix model.In the experiments,various classic classifiers are utilized to benchmark the performance of the proposed method.The results obtained exhibit detection and accuracy rates which are,overall,superior to other techniques. 展开更多
关键词 Crowd behavior spatial-temporal TEXTURE GRAY level CO-OCCURRENCE matrix information ENTROPY
供水管网爆管时空聚类分析研究 预览
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作者 张忠贵 王玉岚 +1 位作者 邓洋 程志远 《湖北第二师范学院学报》 2019年第2期36-38,共3页
供水管网爆管进入高发期,严重影响社会公众生命财产安全。当前主要在静态场景下开展供水管网爆管分析模型研究,忽略供水管网爆管的时空特征,难以准确发现爆管事件的时空分布规律。针对上述问题,在通用的DBSCAN算法基础上,研究供水管网... 供水管网爆管进入高发期,严重影响社会公众生命财产安全。当前主要在静态场景下开展供水管网爆管分析模型研究,忽略供水管网爆管的时空特征,难以准确发现爆管事件的时空分布规律。针对上述问题,在通用的DBSCAN算法基础上,研究供水管网时空聚类分析算法,进行供水管网爆管高发区域分析。 展开更多
关键词 供水管网 时空 聚类分析 爆管
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9.5–2.3 ka BP燕辽地区考古文化演变及其遗址的时空分布(英文)
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作者 袁钰莹 《地理学报:英文版》 SCIE CSCD 2019年第3期449-464,共16页
With basic information from 8353 archaeological sites, this study describes a holistic spatial-temporal distribution pattern of archaeological sites of the prehistoric culture sequence from 9.5 ka BP (ka BP = thousand... With basic information from 8353 archaeological sites, this study describes a holistic spatial-temporal distribution pattern of archaeological sites of the prehistoric culture sequence from 9.5 ka BP (ka BP = thousands of years before 0 BP, where "0 BP" is defined as the year AD 1950) to 2.3 ka BP in the region that extends from the Yanshan Mountains to the Liaohe River Plain(i.e., the Yan-Liao region) in northern China. Based on spatial statistics analysis – including the spatial density of the sites and Geographic Information System nearest-neighbour analysis, combined with a review of environmental and climatic data – this paper analyses cultural evolution, the spatial-temporal features of the archaeological sites and human activities against the backdrop of climatic and environmental changes in this region. The results reveal that prehistoric cultural evolution in the Yan-Liao region is extensively influenced by climatic and environmental changes. The Xinglongwa, Zhaobaogou and Fuhe cultures, which primarily developed during a habitable period from 8.5 ka BP to 6.0 ka BP with strong summer monsoons, have similar maximum density values, spatial patterns and subsistence strategies dominated by hunting-gathering. Significant changes occurred in the Hongshan and Lower Xiajiadian cultures, with a significant increase in numbers and densities of sites and a slump in average nearest-neighbour ratio when the environment began to deteriorate starting in 6.0 ka BP. Additionally, with the onset of a weak summer monsoon and the predominance of primitive agriculture, sites of these two cultures present a different type of concentric circle-shaped pattern in space. As the environment continuously deteriorated with increasing aridity and the spread of steppe, more sites were distributed towards the south, and primitive agriculture was replaced by livestock husbandry in the Upper Xiajiadian culture. The most densely populated areas of the studied cultures are centralized within a limited area. The Laohahe River and Jiaol 展开更多
关键词 PREHISTORIC CULTURAL evolution archaeological site spatial-temporal distribution climate and environmental change Yanshan MOUNTAINS Liaohe River Plain
南京市大气PM2.5时空分布特征与潜在源区贡献分析
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作者 高月 孙荣国 +1 位作者 陈卓 臧庆大 《地球与环境》 CAS CSCD 北大核心 2019年第3期268-274,共7页
对2017年南京市区7个自动空气质量监测点的PM2.5质量浓度ρ(PM2.5)数据进行分析,采用克里金(Kringing)空间插值法、气流运动轨迹聚类、潜在源贡献因子法(PSCF)和浓度权重轨迹分析法(CWT)探讨了四季大气中ρ(PM2.5)的时空分布特征和潜在... 对2017年南京市区7个自动空气质量监测点的PM2.5质量浓度ρ(PM2.5)数据进行分析,采用克里金(Kringing)空间插值法、气流运动轨迹聚类、潜在源贡献因子法(PSCF)和浓度权重轨迹分析法(CWT)探讨了四季大气中ρ(PM2.5)的时空分布特征和潜在来源。结果显示,四季大气中ρ(PM2.5)均值由高到低依次为冬季(65.54 μg/m^3)、春季(41.70 μg/m^3)、秋季(35.18 μg/m^3)和夏季(23.56 μg/m^3),秦淮区四季大气中ρ(PM2.5)均最高。春季南京大气中ρ(PM2.5)易受黄海海岸和北方大陆性输送气流的影响,来自黄海方向的气流轨迹2贡献比例达51.65%,对应的ρ(PM2.5)为50.91 μg/m3;夏季南京大气中ρ(PM2.5)主要受江苏、东部海洋和南部沿海城市输送气流的影响,其中源自江苏的气流轨迹1对南京大气PM2.5贡献比例最大(33.64%),气流轨迹对应的ρ(PM2.5)为35 μg/m^3;秋季南京大气中ρ(PM2.5)易受短距离的偏北气流影响,来自山西南部,河南中部、安徽中部的气流轨迹5对应的ρ(PM2.5)最高,出现概率(21.11%)和贡献比例(27.81%)均较高;冬季南京大气中ρ(PM2.5)主要受北方大陆性输送气流影响,来自俄罗斯、蒙古国东部、河北北部、北京、天津、山东中部的长距离气流轨迹4对应的ρ(PM2.5)最高,达109.8 μg/m^3,其贡献比例为26.86%。PSCF和CWT分析发现,安徽、山东、浙江与江苏交界和黄海海岸是影响南京市空气质量的主要潜在源区,此外,湖北、北京、天津以及渤海海岸也是南京大气PM2.5的潜在源区。 展开更多
关键词 PM2.5 时空特征 轨迹聚类 潜在源贡献因子 浓度权重轨迹分析
一种多视图深度融合的连续性缺失补全方法 预览
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作者 毛莺池 张建华 陈豪 《西安电子科技大学学报》 EI CAS CSCD 北大核心 2019年第2期61-68,共8页
针对现有连续性缺失补全方法的不足,建立了一种多视图深度融合的连续性缺失补全方法。该方法采用反转距离加权插值、双向简单指数平滑、用户协同过滤、能量扩散协同过滤及文本嵌套的方法,分别得到时空和语义缺失数据补全中间结果;构造... 针对现有连续性缺失补全方法的不足,建立了一种多视图深度融合的连续性缺失补全方法。该方法采用反转距离加权插值、双向简单指数平滑、用户协同过滤、能量扩散协同过滤及文本嵌套的方法,分别得到时空和语义缺失数据补全中间结果;构造了神经网络模型融合跨时空和语义视图中的互补异构信息,完成连续性缺失补全。实验表明,该方法补全连续性缺失不但效率高,而且比时空多视图补全在平均绝对误差与平均相对误差上分别降低7%和22%,具备普适性且适用于相关时空连续性缺失序列补全领域。 展开更多
关键词 连续性缺失数据补全 人工神经网络 时空 深度融合
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融合空时显著性的雪天运动目标检测方法 预览
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作者 齐建文 戴德辉 《计算机与数字工程》 2018年第4期727-731,共5页
下雪天存在雪花动态背景噪声,对运动目标检测有较大干扰,现有方法难以解决问题。将空间静态图像的显著性检测方法引入到运动目标检测中,提出了一种适应于雪天的运动目标检测方法,采用空时显著性融合的方法得到运动目标的区域位置信息。... 下雪天存在雪花动态背景噪声,对运动目标检测有较大干扰,现有方法难以解决问题。将空间静态图像的显著性检测方法引入到运动目标检测中,提出了一种适应于雪天的运动目标检测方法,采用空时显著性融合的方法得到运动目标的区域位置信息。实验结果表明,该方法可以有效解决下雪天相机静止情况下的运动目标检测,并在相机移动的动态背景情况中也有一定的检测潜力。 展开更多
关键词 雪天 空时 显著性 运动目标 检测
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