Latent trajectory models for space‐time analysis: An application in deciphering spatial panel data

This article introduces latent trajectory models (LTMs), an approach often employed in social sciences to handle longitudinal data, to the arena of GIScience, particularly space‐time analysis. Using the space‐time data collected at county level for the whole United States through webpage search on the keyword “climate change,” we show that LTMs, when combined with eigenvector filtering of spatial dependence in data, are very useful in unveiling temporal trends hidden in such data: the webpage‐data derived popularity measure for climate change has been increasing from December 2011 to March 2013, but the increase rate has been slowing down. In addition, LTMs help reveal potential mechanisms behind observed space‐time trajectories through linking the webpage‐data derived popularity measure about climate change to a set of socio‐demographic covariates. Our analysis shows that controlling for population density, greater drought exposure, higher percent of people who are 16 years old or above, and higher household income are positively predictive of the trajectory slopes. Higher percentages of Republicans and number of hot days in summer are negatively related to the trajectory slopes. Implications of these results are examined, concluding with consideration of the potential utility of LTMs in space‐time analysis and more generally in GIScience.     

国内城体育场地点高句丽遗址研究

国内城体育场地点遗址是吉林省集安地区一处重要的高句丽建筑遗迹,通过对出土遗物和相关文献等的分析可以发现,体育场地点遗址可能是高句丽时期一处与"御膳房"相关的仓储遗迹,它为寻找国内城时期高句丽的王宫遗址提供了重要线索。体育场地点遗址的年代上限应不早于371年,在高句丽迁都平壤(427年)以后逐渐废弃。     

Performance-based Seismic Design of a Pendulum Tuned Mass Damper System

The study implements the performance-based analysis and design methodology to assess the seismic vulnerability of a coal-fired power plant and to optimally design its equivalent pendulum-type tuned mass damper system such that the direct losses are minimized. A building-specific total loss ratio is developed to link the component level losses with the total repair cost of the original structure. The optimal system configuration is finally derived for cases with the minimum loss. The study demonstrates a systematic way of achieving the optimal pendulum-type tuned mass damper design with considerations of uncertainties in earthquake inputs and the combined component level damages.     

对大型土遗址的植物病害研究——以西安阿房宫遗址为例

在植物对土遗址作用的研究中,鲜有就真实的遗址来展开调查,以及讨论植物给土遗址带来的负作用及其机理。为此,本研究选取西安地区大型土遗址秦阿房宫为研究对象,利用现场调查结合样带法、图像分析法并采集土样,开展对遗址区植物分布、根系产生的裂隙和土壤环境的研究。结果表明:造成土遗址病害现象的主要原因为植物根系作用,加之雨蚀、风化作用及人为破坏的叠加作用,使遗址保存面临严重威胁;其中酸枣、臭椿等萌生树种所产生的根劈裂隙及植物根系对土壤环境的影响十分明显。现存土遗址由植物以及风雨作用而引发的主要病害,其类型包含了边缘夯土的基础掏蚀、洞穴遗存、开裂坍塌、冲沟发育、表面剥蚀,这些是阿房宫遗址面临的主要威胁,也是半干旱地区土遗址存在的特有问题。研究结果既有助于揭示植被对土遗址的作用机理,又能为土遗址保护的植物选择提供理论依据和技术支撑。     

中国城市群空间结构演化的影响因素分析——基于铁路客运的功能联系视角

以中国13个城市群为研究对象,采用铁路客运班次构造多中心指数来表征基于功能联系的城市群空间结构,在分析城市群空间结构演变基础上重点分析其影响因素。研究发现,基于功能联系视角的城市群空间结构总体呈单中心化趋势,但地区差异化明显,珠三角、山东半岛和闽东南城市群已表现出多中心化特征;城市群空间结构的多中心程度随经济发展水平的提高表现为先单中心后多中心的演变过程;城市群规模的增大和城市间联系加强促进了城市群向多中心方向演化;而面积小、三产比重高的城市群更有利于形成单中心的结构;政府干预作用对城市群空间结构影响并不显著。鉴于不同城市群空间结构演化趋势不同,未来政策取向应该遵从各个城市群自身规律。     

世界城市网络研究的热点变迁及主题判别——基于WOS数据库的知识图谱分析

借助可视化软件,从梳理研究热点及识别研究主题两方面,厘清世界城市网络的研究脉络与核心,探索未来研究动向。研究发现：①世界城市网络研究国际合作广泛,研究热点响应迅速,经历“世界城市”与“世界体系”分化阶段,网络结构聚焦阶段,城市网络的空间、地位、经济等多元阶段变迁;②研究由城市网络链接结构、全球中心城市、城市网络节点地位及城市网络经济学四大主题构成;③以往研究缺乏对网络结构绩效的研究,对非世界城市的关注不够,城市地位与经济之间的关系仍处于描述阶段;④对世界城市网络结构的内涵、非世界城市研究、整体网络与个体网络关系、经济学方向进行展望,使世界城市网络的未来研究更加全面丰富。     

4. IS THERE A CHINESE MODE OF HISTORICAL THINKING? A CROSS‐CULTURAL ANALYSIS

Taking Chun‐chieh Huang's ruminations on the defining character of Chinese historical thinking as a starting point, this essay discusses the ways in which historical cultures and traditions are compared and contrasted and explores some new ways of thinking. It argues that cultural comparisons often constitute two‐way traffic (one begins to examine itself after encountering the other) and that attempts to characterize one historical culture, such as that of China, are often made relationally and temporally. When the Chinese tradition of historiography is perceived and presented in the West, it has been regarded more or less as a counterexample against which the “unique” traits of Western historical thinking are thrown into relief. Given the hegemonic influence of Western scholarship in modern times, latter‐day Chinese historians also valorize the East—West dichotomy. A closer look at this dichotomy, or the characterization of both cultures, reveals that it is not only relative but also relational and temporal. When the modern Chinese appeared impressed by the rigor of Rankean critical historiography, for example, they were essentially attempting to rediscover their own cultural past, for example, the eighteenth‐century tradition of evidential learning, in adapting to the changing world. Our task today, the essay contends, is to historicize the specific context within which cultural comparisons are made and to go beyond readily accepted characterizations in order to reassess certain elements in a given culture, to apply historical wisdom, and to cope with the challenges we now face.     

What can pollen grains from the Terracotta Army tell us?

The provenance of more than 2200-year-old terracotta warriors and horses in the Qin Shihuang Mausoleum is still a mystery, even though some researchers have inferred that the terracotta figures were produced near the mausoleum. The sporomorphs (pollen and spores) extracted from terracotta fragments of a warrior and a horse and compared with those obtained from soil samples from the Qin Dynasty layer in Pit No. 2 of the Qin Shihuang Mausoleum indicate that the pollen spectrum from the terracotta horse is different from that of the warrior, but similar to the local soil samples. Herbaceous pollen was dominant in the warrior sample, while arboreal pollen predominates in the horse and soil samples. Palynological evidence suggests that the terracotta horses were produced at a locality near the mausoleum, while the warrior came from a site which was further afield.