劳动力区际流动及其人力资本再分配效应——基于技能互补性假说的理论与实证分析     

敖荣军 《地理与地理信息科学》2007,23(1):59-63

由于劳动力的异质性,不同技能劳动力之间的合作和互补可以获得递增收益。客观存在的技能互补性导致技能劳动力迁入与迁入地技能劳动力需求之间的正反馈关系,从而引发了劳动力区际流动与人力资本地区集中之间的累积循环。该文基于Giannetti提出的技能互补性假说,从一个新的角度对劳动力区际流动的动因进行理论与实证分析,并揭示该假说的区域经济学含义。  相似文献   

基于多源时空大数据的区际迁徙人群多层次空间分布估算模型——以COVID-19疫情期间自武汉迁出人群为例   总被引：3，自引：0，他引：3  

刘张  千家乐  杜云艳  王楠  易嘉伟  孙晔然  马廷  裴韬  周成虎 《地球信息科学学报》2020,22(2):147-160

已有研究很少关注区际迁徙人群在不同尺度上空间分布的动态估算问题。COVID-19疫情爆发以来,坚决防止疫情扩散成为社会最紧迫的事情。在2020年1月23日武汉“封城”前夕,已有500多 万人离开了武汉,快速准确地推算这部分人群的去向,可以为防止疫情扩散和制定防疫决策提供科学依据。本文以此为例,基于开源腾讯位置请求大数据、百度迁徙大数据、土地覆盖数据等多源地理时空大数据,提出一种区际迁徙人群多层次空间分布动态估算模型,用于推算2020年除夕 （2020年1月24日）之前从武汉流入湖北省内各地的人群数量及其分布特征。结果显示：① 春节时段湖北省各地级市农村地 区人群增加数量占人群变化总量的比例平均达124.7%,从武汉市迁入各地级市的人群中至少51.3%流入农村地区;② 区县尺 度人群变化总量的空间分布呈现3个圈层结构：第一圈层为疫情核心区,包括武汉及其周边地区,以人群流出为主;第二圈层为 重点关注区,包括黄冈、黄石、仙桃、天门、潜江、随州、襄阳,以及孝感、荆门、荆州和咸宁的部分地区,以人群总量和农村地区人 群数量大幅增加为主;第三圈层为次级关注区,包括湖北西部宜昌、恩施、神农架和荆门部分地区,以人群小幅流入为主。最后,建议湖北省内,尤其是位于第二圈层内的区县,应高度关注农村地区人群的疫情防控。此研究成果在2~3天完成,显示大数据是可以快速地响应重大公共安全事件,为决策的制定提供一定支持的。  相似文献   

Mining online footprints to predict user’s next location     

Qunying Huang 《International journal of geographical information science》2017,31(3):523-541

Social media applications are widely deployed in mobile platforms equipped with built-in GPS tracking devices, and these devices have led to an unprecedented collection of geolocated data (geo-tags). Geo-tags, along with place names, offer new opportunities to explore the trajectory and mobility patterns of social media users. However, trajectory data captured by social media are sparsely and irregularly spaced and therefore have varying degrees of resolution in both space and time. Previous studies on next location prediction are mostly applicable for detecting the upcoming location of a moving object using dense GPS trajectories where locations are recorded at regular time intervals (e.g., 1 minute). Additionally, point features are commonly used to represent the locations of visits, but using point features cannot capture the variability of human mobility. This article introduces a new methodology to predict an individual’s next location based on sparse footprints accumulated over a long time period using social networks, and uses polygons to represent the location corresponding to the physical activity area of individuals. First, the density-based spatial clustering algorithm is employed to discover the most representative activity zones that an individual frequently visits on a daily basis, and a polygon-based region is then derived for each representative activity zone. A sparse mobility Markov chain model considering both the movements and online behaviors of the social media user is trained and used to predict the user’s next location. Initial experiments with a group of Washington DC Twitter users demonstrate that the proposed methodology successfully discovers the activity regions and predicts the user’s next location with accuracy approaching 78.94%.  相似文献   

A collective human mobility analysis method based on data usage detail records     

Hao Jiang  Qian Li  Xian Zhou  Yanqiu Chen  Shuwen Yi  Hai Wang 《International journal of geographical information science》2017,31(12):2359-2381

Human mobility patterns have been widely investigated due to their application in a wide variety of fields, for example urban planning and epidemiology. Many studies have introduced spatial networks into human mobility analyses at the collective level. However, these studies merely analyzed spatial network structure, and the underlying collective mobility patterns were not further discussed. In this paper, we propose a collective mobility discovery method based on community differences (CMDCD). We constructed spatial networks where nodes represent geographical entities and edge weights denote collective mobility intensity between geographical entities. The differences between communities detected from the networks constructed in different periods were then identified. Since collective spatial movement has a large influence on network structure, we can discover groups with different mobility patterns based on community differences. By applying the method to data usage detail records collected from the cellular networks in a city of China, we analyzed different collective mobility patterns between the Spring Festival vacation and workdays. The experimental results show that our method can solve these two problems of identifying community differences and discovering users with different mobility patterns simultaneously. Moreover, the CMDCD method is an integrated approach to discover groups whose mobility patterns have changed in different periods at the large spatial scale and the small spatial scale. The discovered collective mobility patterns can be used to guide urban planning, traffic forecasting, urban resource allocation, providing new insights into human mobility patterns and spatial interaction analyses.  相似文献   

Residential mobility in the Seoul metropolitan region, Korea   总被引：3，自引：0，他引：3  

Yongwoo Kwon  Jawon Lee 《GeoJournal》1997,43(4):389-395

The spatial pattern of residential mobility in Korea is found to be one of intraregional rather than interregional movement. Net inmigration has taken place only in the Seoul metropolitan region (SMR) since 1970. People from the Cholla region have formed the main stream of net inmigration into the SMR. The decentralization of population from Seoul to Kyonggi and Inchon has generated a transformation of the Seoul urban fringe since 1970. This metropolitanization process is accompanied by residential and employment suburbanization to 45kms from the center of Seoul. Residential mobility in the SMR is the result of metropolitan job opportunities, availability of housing, and the effects of the various regional policies. Availability of transportation between Seoul and its urban fringe encouraged the wide expansion of the urban areas and population redistribution within the SMR.  相似文献   

Mobility of rare-earth elements and copper during shear-zone-related retrograde metamorphism     

de Jong  Geoffrey  Rotherham  Jackie  Phillips  G. Neil  Williams  Patrick J. 《Geologie en Mijnbouw》1997,76(4):311-319

In Mid Proterozoic crystalline rocks of the Mount Isa Inlier, around Cloncurry, Australia, 2000 km² of alteration and brecciation are the product of high-temperature (> 450 °C) concentrated saline solution activity. During retrogression, this fluid was locally responsible for mobility of V, Y, Nb and light rare-earth elements (15 × enrichment). Copper and S were leached during alteration and this may have been a significant source of components in nearby Cu-Au deposits. Similar rare-earth-element behaviour has been observed in the hematite breccias which host Cu-sulfides at the giant Olympic Dam Cu-Au deposit.  相似文献   

不同模式道路网交通便捷性比较     

曹炜威  张红  沈富强  朱齐华 《地理信息世界》2016,(4):25-30

道路网在城市发展中起着关键作用。交通便捷的城市,往往与其他城市经济贸易等交流频繁,在区域中能够获得更好的发展机会,并能有效节约社会资源。城市道路网呈多种模式,不同模式道路网独有的几何和结构特征导致其交通便捷性差异明显,但对这种差异缺乏定量分析和比较。本文基于目视观察大量城市数字地图,认为真实道路网基本呈格网、环形放射、自由3种典型模式。针对以上典型模式,定义用于描述交叉口之间移动难易程度的无效移动系数和通达度指标,结合现有的连接度指标采用网络分析方法分别从几何和结构的角度比较不同模式道路网的交通便捷性差异。结果表明,格网和环形放射模式无效移动系数低,邻近交叉口之间距离多为有效移动,道路网连接度较高,交通便捷性良好。自由模式道路走向任意,难以有效连线构网,相邻交叉口之间无效移动系数较大,连接度相对低,便捷性相对较差。受规模因素的影响,格网模式交叉口之间平均最短路径较大,消除规模因素影响整体道路网具有良好的通达性。  相似文献   

中国锆资源利用现状及其进出口形势分析     

刘皓阳  李建武 《地质论评》2016,62(S1):11-12

锆（Zirconium）的原子序数是40,是一种银白色过渡金属,因其制取工艺复杂,不易被提取,所以也常被称为“稀有金属”。锆在空气中表面易形成一层氧化膜,具有光泽,故外观与钢相似。锆耐腐蚀性很强,但是可溶于氢氟酸和王水;高温时,可与非金属元素和许多金属元素反应。锆作为一种相对稀缺性资源,被广泛地应用于电子、陶瓷、玻璃、石化、建材、医药、纺织以及日用品等领域。由于具有惊人的抗腐蚀性能、极高的熔点、超高的硬度和强度等特性,锆在航空航天、军工、核反应、原子能领域也有着不可或缺的地位。核级锆材作为核反应堆堆芯核燃料的包壳材料,与核工业的发展密切关联,在国家战略安全领域具有特殊意义。  相似文献   

Understanding the bias of call detail records in human mobility research   总被引：1，自引：0，他引：1  

Ziliang Zhao  Yang Xu  Feng Lu  Jie Chen  Ling Yin 《International journal of geographical information science》2016,30(9):1738-1762

ABSTRACT

In recent years, call detail records (CDRs) have been widely used in human mobility research. Although CDRs are originally collected for billing purposes, the vast amount of digital footprints generated by calling and texting activities provide useful insights into population movement. However, can we fully trust CDRs given the uneven distribution of people’s phone communication activities in space and time? In this article, we investigate this issue using a mobile phone location dataset collected from over one million subscribers in Shanghai, China. It includes CDRs (~27%) plus other cellphone-related logs (e.g., tower pings, cellular handovers) generated in a workday. We extract all CDRs into a separate dataset in order to compare human mobility patterns derived from CDRs vs. from the complete dataset. From an individual perspective, the effectiveness of CDRs in estimating three frequently used mobility indicators is evaluated. We find that CDRs tend to underestimate the total travel distance and the movement entropy, while they can provide a good estimate to the radius of gyration. In addition, we observe that the level of deviation is related to the ratio of CDRs in an individual’s trajectory. From a collective perspective, we compare the outcomes of these two datasets in terms of the distance decay effect and urban community detection. The major differences are closely related to the habit of mobile phone usage in space and time. We believe that the event-triggered nature of CDRs does introduce a certain degree of bias in human mobility research and we suggest that researchers use caution to interpret results derived from CDR data.  相似文献   

“Contested policy mobility”: the creative transformation and temporary use of brownfields in Redtory,Guangzhou     

Xuan Liu 《Urban geography》2017,38(6):884-902

This article argues that the changing distribution of power between coalitions of stakeholders challenges typical top-down dynamics of policy mobility, and causes contestations that in turn lead to the multi-scalar co-construction of policy- and place-making in China. When property-led redevelopment, commandeered by the coalition between government and investors, could no longer dominate the renewal of brownfield sites, a nationally endorsed mobile policy of creative transformation led China’s renewal of these areas into a new phase of “contested policy mobility”. Three kinds of contestations have been observed in Redtory, Guangzhou. First, in adopting the alternative mobile policy of using brownfields temporarily before permanent redevelopment, local governments were aiming to retain control of development rights throughout a nationally mandated urban economic “creative transformation” process. Second, emerging new interest groups from within the public sphere were able to resist subsequent redevelopment plans, thereby challenging the mobile policy’s top-down momentum. Finally, divisive interests within the coalition ultimately weakened their power when contesting the government and investors.  相似文献