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401.
南京内城商业绅士化发育特征研究   总被引:5,自引:0,他引:5  
商业绅士化是指城市中传统商业、居住或工业被更高价值商业取代和置换的现象,与居住绅士化互为因果。由于城市发展阶段、模式和管制环境不同,不同国家和地区商业绅士化社会空间特征表现出显著差异。20世纪末以来,在城市社会空间转型语境下,具有异域风情的餐厅、酒吧、咖啡馆、健身房等高档消费场所置换传统住宅或社区商业并在城市特定空间中集聚,是中国最典型的商业绅士化现象。遴选出符合商业绅士化特征的六类高端商娱场所,采用空间核密度等方法,对2008年和2018年南京内城上述商娱场所空间集聚、演进模式和机理效应进行分析。研究发现:① 商业绅士化“热点区”首先出现在城市传统商业中心和文化历史街区,随后向商业中心周边和新兴商业地段跳跃式扩散;② 根据实践路径差异,可将南京内城商业绅士化分为整体植入式、侵入演替式和转型升级式三种模式,分别以1912街区、南京大学—南京师范大学(南大—南师大)片区和新街口地区为代表;③ 经济和文化力量在推动商业绅士化的发生演化中均发挥重要作用,其中地方政府、资本联手对“商业租差”的追逐,以及年轻、高收入绅士化群体日益增长的时尚、高端文化消费需求,从供需两端驱动着商业绅士化过程;④ 商业绅士化在提升城市商业活力和经济效益的同时,也在一定程度上产生对原住居民和低端商业的排挤和置换效应。  相似文献   
402.
403.
Open data strategies are being adopted in disaster-related data particularly because of the need to provide information on global targets and indicators for implementation of the Sendai Framework for Disaster Risk Reduction 2015–2030. In all phases of disaster risk management including forecasting, emergency response and post-disaster reconstruction, the need for interconnected multidisciplinary open data for collaborative reporting as well as study and analysis are apparent, in order to determine disaster impact data in timely and reportable manner. The extraordinary progress in computing and information technology in the past decade, such as broad local and wide-area network connectivity (e.g. Internet), high-performance computing, service and cloud computing, big data methods and mobile devices, provides the technical foundation for connecting open data to support disaster risk research. A new generation of disaster data infrastructure based on interconnected open data is evolving rapidly. There are two levels in the conceptual model of Linked Open Data for Global Disaster Risk Research (LODGD) Working Group of the Committee on Data for Science and Technology (CODATA), which is the Committee on Data of the International Council for Science (ICSU): data characterization and data connection. In data characterization, the knowledge about disaster taxonomy and data dependency on disaster events requires specific scientific study as it aims to understand and present the correlation between specific disaster events and scientific data through the integration of literature analysis and semantic knowledge discovery. Data connection concepts deal with technical methods to connect distributed data resources identified by data characterization of disaster type. In the science community, interconnected open data for disaster risk impact assessment are beginning to influence how disaster data are shared, and this will need to extend data coverage and provide better ways of utilizing data across domains where innovation and integration are now necessarily needed.  相似文献   
404.
The development of new sensors and easier access to remote sensing data are significantly transforming both the theory and practice of remote sensing. Although data-driven approaches based on innovative algorithms and enhanced computing capacities are gaining importance to process big Earth Observation data, the development of knowledge-driven approaches is still considered by the remote sensing community to be one of the most important directions of their research. In this context, the future of remote sensing science should be supported by knowledge representation techniques such as ontologies. However, ontology-based remote sensing applications still have difficulty capturing the attention of remote sensing experts. This is mainly because of the gap between remote sensing experts’ expectations of ontologies and their real possible contribution to remote sensing. This paper provides insights to help reduce this gap. To this end, the conceptual limitations of the knowledge-driven approaches currently used in remote sensing science are clarified first. Then, the different modes of definition of geographic concepts, their duality, vagueness and ambiguity, and the sensory and semantic gaps are discussed in order to explain why ontologies can help address these limitations. In particular, this paper focuses on the capacity of ontologies to represent both symbolic and numeric knowledge, to reason based on cognitive semantics and to share knowledge on the interpretation of remote sensing images. Finally, a few recommendations are provided for remote sensing experts to comprehend the advantages of ontologies in interpreting satellite images.  相似文献   
405.
Prior to the COVID-19 crisis, global air transport demand was expected to triple between 2020 and 2050. The pandemic, which reduced global air travel significantly, provides an opportunity to discuss the scale, distribution and growth of aviation until 2018, also with a view to consider the climate change implications of a return to volume growth. Industry statistics, data provided by supranational organizations, and national surveys are evaluated to develop a pre-pandemic understanding of air transport demand at global, regional, national and individual scales. Results suggest that the share of the world’s population travelling by air in 2018 was 11%, with at most 4% taking international flights. Data also supports that a minor share of air travelers is responsible for a large share of warming: The percentile of the most frequent fliers – at most 1% of the world population - likely accounts for more than half of the total emissions from passenger air travel. Individual users of private aircraft can contribute to emissions of up to 7,500 t CO2 per year. Findings are specifically relevant with regard to the insight that a large share of global aviation emissions is not covered by policy agreements.  相似文献   
406.
陈雯  王学山  周勤 《湖泊科学》2003,15(Z1):266-272
废水排污权交易地区交叉补贴的设想是通过建立上下游地区之间的排污权交易模型,将下游地区的排污权交易所得向上游地区转移,解决上游地区对下游地区的二次污染问题,从而减少流域污染.本文在污染权交易基本思路和研究进展的基础上,在并不考虑交易成本的假设下,建立了流域污染总量分配模型和存在收入差别的地区间污染源排污权分配模型,以此来确定污染的总量分配及价格,计算污染权的地区分配及其收益.太湖流域由于经济最为发达,环境问题十分突出,是目前我国最适宜率先实施污染权交易试点的地区,因此假定以江苏省无锡和常州两个相邻城市进行污染权交易作为试点,运用上述模式,以分别计算基准价格、排污权交易量和交易效用,研究结果显示出交易具有明显的经济和环境效应.  相似文献   
407.
以黑河中游平川绿洲和六坝绿洲为例,对绿洲及绿洲-荒漠生态过渡带土壤含水量空间分异进行了分析研究。结果表明:在无灌溉条件下绿洲及绿洲-荒漠生态过渡带的土壤含水量水平分异明显,绿洲土壤含水量高于绿洲-荒漠生态过渡带和荒漠地区土壤含水量,并出现从绿洲到绿洲-荒漠过渡带和荒漠依次递减的趋势,主要受土壤性状、土壤水分水平运动和绿洲-荒漠局地大气环流影响;绿洲活动层土壤含水量垂直分异上表现为从表层向下逐渐增加,而过渡带和荒漠区活动层土壤含水量垂直分异则是表层和底层比20~30cm处低,可能与荒漠土壤凝结水的形成与运动有关。受绿洲地下水过度开采和绿洲边缘人类活动影响,在绿洲-荒漠过渡带形成了生态裂谷,对绿洲生态系统的安全构成威胁。  相似文献   
408.
近壁圆柱绕流水动力特性数值模拟与实验研究   总被引:3,自引:0,他引:3  
通过数值模拟和物理模型实验,对距壁面一定高度的圆柱绕流水动力特性进行了研究。数值模拟采用有限体积法对标准k-ε模式方程进行离散,采用SIMPLE算法进行求解,模拟绕流流场。在物理模型实验中,将PVC圆管制作的实验模型安放在水槽内,在圆管的跨中沿表面周向均匀布置水下压力传感器,用于测量绕流圆柱体表面动水压力分布。通过改变Re数和间隙比来分析它们对近壁圆柱绕流水动力特性的影响。基于数值流动显示技术,给出了近壁绕流流场的尾流流态分析。通过数值结果与实验结果的对比,对近壁绕流圆柱体的升力系数及其表面动水压力分布进行了研究,对比结果显示了较好的一致性。  相似文献   
409.
针对石墨间隙不同间距的配合使用问题,根据其工作原理并结合汤逊气体放电理论,采用1.2/50 μs开路电压波和8/20μs短路电流波对不同级数的石墨间隙进行试验,结果表明:电压保护水平随着间隙距离的增加而增加,当间隙距离超过2 mm时,电压保护水平远大于IEC规定的2.5 kV.石墨间隙的残压、通流和动作响应时间都随着石...  相似文献   
410.
将动态空区预报地震的方法同静态空区法作了详细的比较分析.发现用动态空区法所确定的震中位置的精度比静态空区法高,而且,在估计发震时间和震级方面也比静态空区法有很大的改善.  相似文献   
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