移动对象多种运动参数在轨迹分类的应用

轨迹分类是以训练轨迹的特征来预测未知轨迹的类标签,可进行可疑车辆识别、非法渔船检测和交通模式检测等重要应用。当前大多数轨迹分类方法只考虑速度和加速度这2个运动参数,且只利用简单的统计量（如均值、中值、最大值）,不能充分挖掘轨迹的潜在特点,导致分类精度不高。针对该问题,本文在总结相关文献的基础上,提出一种基于移动对象运动特征的轨迹分类方法。针对速度、加速度、曲率、方向和转角这5个运动参数,利用偏度系数、峰度系数、变异系数和时间序列分析其中的自相关系数等,提取有区分力的全局运动特征;并从分割后的子轨迹中提取局部运动特征。对于方向和转角,引入方向统计学对其运动特征进行精确计算。实验表明本方法在船舶、野生动物和飓风数据集的分类精度达到了100%、80%和71.43%,实验验证了本方法构建的运动特征,在不同数据集下有效可行。     

基于巡回的北京市居民出行时空间决策的社区分异

国内以往关于城市空间结构与居民出行行为之间关系的研究主要建立在出行角度的分析之上,以巡回作为基本单元,从出行决策视角探讨居民出行时空间决策社区分异的研究尚少见报导。利用2007年北京市居民活动日志调查获取的第一手数据,构建基于巡回的出行时空间决策概念模型,并采用嵌套Logit对北京市居民工作日出行时空间决策的社区分异进行探讨。结果表明:居民巡回类型决策的社区分异较为显著,但会随出行目的变化而发生较大变化;巡回中主要活动起始时间决策的社区分异并不显著,但起始时间与活动类型存在较强的内在联系;出行距离及交通方式决策的社区分异较为显著,对单位社区及政策性住房社区应给予更多的研究和关注。     

基于双效机制的时空数据模型研究

地理特征对象是时空数据组织的基本单元,而事件是导致时空数据发生变化的根本原因。在分析、借鉴前人的时空数据管理方法的基础上,通过分析事件驱动的特征对象数据存储与管理机制,提出了一种基于特征和事件双效机制的TG IS时空数据模型。同时结合土地利用的时空数据特点,设计了基于该模型的时空数据的快速索引机制和时空数据库。实际运行表明基于该模型的TG IS系统设计方案能高效、快速、全面地实现时空数据的存储、管理和分析。     

GIS时空数据模型在城市地下管线数据库中的应用

城市地下管线信息的动态增加、变更、废弃等导致了地下管线信息管理与信息系统开发的复杂性与难度。本文针对管线信息的时空特性,给出了一个图形与属性一体化存储的面向对象的GIS时空数据模型,很好地解决了城市地下管线数据的动态更新、历史信息管理、现状查询分析等难题,并对数据库的设计进行了较详细的描述。该模式对大中城市综合地下管线系统的建设具有很好的借鉴和指导意义。     

河南省县域就地城镇化时空演变与影响机理研究

中国的就地城镇化被视为城乡界限淡化条件下人类聚落系统发生重大改变的证据之一。已有文献大多局限在城乡二元分析框架内,本文基于城乡界限淡化的背景建立县域就地城镇化模型,对河南省108个县市2006—2016年就地城镇化水平的整体格局、空间聚类和热点区域演化进行分析。研究结果显示：① 河南省大多数县市就地城镇化水平有了明显提升,但大部分县市仍处低水平发展阶段,就地城镇化水平相对差异呈扩大趋势。② 河南省就地城镇化空间演化特征明显,“L”形豫北-豫东板块就地城镇化先行区凸显,豫西整体城镇化水平虽低但发展后劲足,连片发展态势明显。③ 河南省县域就地城镇化全局自相关性十分显著,空间聚集倾向和空间近邻效应日益显现,但仅出现了小范围的高聚类区和低聚类区。④ 河南省县域就地城镇化的热点区、冷点区分布格局变化较大,但次冷区和次热区基本保持稳定状态。⑤ 基于极大似然估计的实证检验结果表明,基础设施建设水平、城镇就业规模、人口规模和财政支出水平等是影响河南省县域就地城镇化水平的重要因素。基于上述研究结论,本文提出应从加快推进户籍制度和就业创业制度改革、完善农业土地流转和征地补偿制度、加快城乡结合部新型农村社区建设等方面提升就地城镇化建设质量和水平。     

山东省基础教育师资配置的时空格局与影响因素

以师生比为衡量指标,采用标准差、变异系数及探索性空间数据分析等方法对2000—2019年山东省基础教育阶段师资配置的时空格局与影响因素进行分析。结果表明:2000—2019年山东省小学师生比呈平缓波动趋势,中学师生比总体呈现上升趋势,且具有明显阶段性特征。山东省小学师生比空间过程呈现由“极核式”向“条带式”演变特征,高值区具有明显中心外围的圈层结构特征,鲁西南、鲁西北及鲁东南形成了低水平塌陷区;中学师生比空间上呈现不均衡向均衡迈进的趋势,高值区由多核心演变为单核心结构,低值区连片分布于鲁西南、鲁中、鲁东南及鲁北地区,且呈现半环带状圈层结构特征。山东省中小学师生比存在显著的空间俱乐部趋同特征,高值先导区以山东半岛为主,低值陷阱区分布于鲁西南和鲁北部分地区。教育政策与制度、人口结构变动、区域发展不均衡、空间近邻效应是基础教育师资配置差异的重要原因。     

气候变化背景下1981-2010年中国玉米物候变化时空分异

基于中国玉米种植区内114个农气站1981-2010年的长序列物候观测数据,量化分析了玉米8个连续物候期的时空分异特征和相应的生长阶段长度变化规律。结果表明：1981-2010年间,玉米生育期内平均温度和有效积温(GDD）呈现增加趋势,降水量和日照时数呈现减少趋势。气候变化背景下,玉米物候期发生了显著变化。春玉米物候期以提前趋势为主,包括西北内陆玉米区春玉米、西南山地丘陵玉米区春玉米;夏玉米和春夏播玉米各物候期在不同区域均呈现推迟的趋势,西北内陆玉米区夏玉米各物候期推迟的幅度大于黄淮平原夏玉米各物候期推迟的幅度。玉米物候期的变化改变了相应生长阶段的长度,中国春/夏/春夏播玉米营养生长期（播种期—抽雄期）呈现不同程度的缩短趋势,而对应的生殖生长期（抽雄期—成熟期）呈现不同程度的延长趋势;春玉米生育期（播种期—成熟期）延长,夏/春夏播玉米生育期缩短。     

Spatio-temporal evolution of population and urbanization in the countries along the Belt and Road 1950–2050

This paper uses data for the period 1950–2050 compiled by the United Nations Population Division together with methods including spatial autocorrelation analysis, hierarchical cluster analysis and the standard deviational ellipse, to analyze the spatio-temporal evolution of population and urbanization in the 75 countries located along the routes of the Silk Road Economic Belt and the 21st-century Maritime Silk Road, to identify future population growth and urbanization hotspots. The results reveal the following: First, in 2015, the majority of Belt and Road countries in Europe, South Asia and Southeast Asia had high population densities, whereas most countries in Central Asia, North Africa and West Asia, as well as Russia and Mongolia, had low population densities; the majority of countries in South Asia, Southeast Asia, Central Asia, West Asia and North Africa had rapid population growth, whereas many countries in Europe had negative population growth; and five Belt and Road countries are in the initial stage of urbanization, 44 countries are in the acceleration stage of urbanization, and 26 are in the terminal stage of urbanization. Second, in the century from 1950 to 2050, the mean center of the study area’s population is consistently located in the border region between India and China. Prior to 2000, the trajectory of the mean center was from northwest to southeast, but from 2000 it is on a southward trajectory, as the population of the study area becomes more concentrated. Future population growth hotspots are predicted to be in South Asia, West Asia and Southeast Asia, and hotspot countries for the period 2015–2030 include India, China, Pakistan and Indonesia, though China will move into negative population growth after 2030. Third, the overall urban population of Belt and Road countries increased from 22% in 1950 to 49% in 2015, and it is expected to gradually catch up with the world average, reaching 64% in 2050. The different levels of urbanization in different countries display significant spatial dependency, and in the hundred-year period under consideration, this dependency increases before eventually weakening. Fourth, between 2015 and 2030, urban population hotspots will include Thailand, China, Laos and Albania, while Kuwait, Cyprus, Qatar and Estonia will be urban “coldspots.” Fifth, there were 293 cities with populations over 1 million located along the Belt and Road in 2015, but that number is expected to increase to 377 by 2030. Of those, 43 will be in China, with many of the others located in India, Indonesia and the eastern Mediterranean.     

Spatio-temporal evolution of drought and flood disaster chains in Baoji area from 1368 to 1911

Based on the collation and statistical analysis of flood and drought information in Baoji area from 1368 to 1911, and in the context of climate change, we investigated the spatio-temporal evolution characteristics of drought and flood disaster chains in this area during the Ming and Qing dynasties using the methods of moving average, cumulative anomaly and wavelet analysis. The results are as follows: (1) We found a total of 297 drought and flood events from 1368 to 1911 in Baoji. Among these events, droughts and floods occurred separately 191 and 106 times, which accounted for 64.31% and 35.69% of the total events, respectively. (2) We observed distinct characteristics of flood and drought events in Baoji in different phases. The climate was relatively dry from 1368 to 1644. A fluctuant climate phase with both floods and droughts occurred from 1645 to 1804. The climate was relatively wet from 1805 to 1911. Moreover, we observed a pattern of alternating dry and wet periods from 1368 to 1911. In addition, 3 oscillation periods of drought and flood events occurred around 70 a, 110 a and 170 a, which corresponded to sunspot cycles. (3) We also observed an obvious spatial difference in drought and flood events in Baoji. The northern and eastern parts of Weihe River basin were regions with both frequent droughts and floods. (4) The sequential appearance of drought and flood disaster chains in Baoji from 1368 to 1911 was in response to global climate change. Since the 1760s, global climatic deterioration has frequently led to extreme drought and flood events.     

黄淮海平原耕地功能演变的时空特征及其驱动机制

本文以县域为基本研究单元,从经济、社会及生态三个维度构建了耕地功能评价指标体系,分析了黄淮海平原耕地功能演化的时空特征,利用耦合动态度模型探讨了耕地功能间耦合关系的演变。在此基础上,利用空间计量模型,对耕地功能演化的驱动机制进行了定量分析。研究结果表明：① 1990-2010年间,冀中南及豫东地区部分欠发达县市耕地经济功能明显增强,发达的城市群及其腹地受工业化及城镇化影响较大,耕地经济功能持续下降;60.29%的县域单元耕地的社会功能下降,增强区主要集聚于郑州北部、德州及沧州西部、烟台、威海等区域;生态功能变化在空间格局上基本形成了以豫北、山东中部山地丘陵区为核心的增长区以及以环京津、环济南地区为核心的持续下降区。② 黄淮海平原耕地经济、社会及生态功能的耦合度及协调度空间差异显著,且退耦化现象日渐突出;经济发达地区耕地的社会及生态功能演化速率普遍滞后于经济功能。③ 黄淮海平原耕地的功能演化是区域本底因素与外部驱动因素综合作用的结果;城镇化与工业化进程中人口、产业的转型对耕地经济、社会及生态功能演化的强度及方向起决定性作用。并指出：黄淮海平原应激活农业现代化、产业化发展动力,促进传统农业的转型升级,充分考虑耕地功能演化的区域分异特征,实行由发达城市地区到欠发达传统农区的差异化、多元化的耕地多功能利用与管理模式。