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331.
A Numerical Verification of Self-Similar Multiplicative Theory for Small-Scale Atmospheric Turbulent Convection 下载免费PDF全文
The self-similar multiplicative theory(SSM theory), aims to interpret the scaling behavior of the temperature structure function. In the present paper, the author report results from a numerical simulation of atmospheric turbulent convection in order to verify this theory. The simulation was based on a shell model which was deduced from simplified atmospheric convection equations. The numerical results agreed well with the theory prediction of scaling law from the first order to the eighth order. They also showed that the prediction of this theory was better than that given by the Kolmogorov's theory in 1941, log-normal, and β model theories. 相似文献
332.
基坑及周边建筑物变形监测方案 总被引:1,自引:0,他引:1
结合某基坑变形监测项目,从观测墩及觇牌的设计、观测方法、精度估计等方面对基坑水平位移观测进行了介绍,并介绍了利用差异沉降量推算法进行倾斜观测的方法. 相似文献
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The study area is located near the town of Filippoi, north of the city of Kavala in northern Greece, known from ancient times for its rich gold mines, situated inside hydrothermal alteration zones (Fe–Mn oxide minerals). A Very High-Resolution (0.5 m pixel size) image of Worldview-2 satellite was digitally enhanced, yielding target areas of potential ore existence and lineaments. Ground-truth that followed digital image processing, revealed abandoned ancient mines, slags and ore occurrences. Also, a number of lineaments delineated on the satellite image were verified as faults. 相似文献
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以陕北某湿陷性黄土大厚度挖方地基工程为研究对象,采用PS-InSAR技术对2018-10—2019-11间获取的16景TerraSAR-X卫星影像进行处理,获取了湿陷性黄土挖方区回弹变形信息,总结了大厚度挖方区时序回弹变形特征。结果表明,由于上部土体应力卸载,在开挖区域存在地基土回弹变形现象,选取的高密度PS点变形信息较好地反映了研究区的真实变形情况,回弹变形范围与开挖边界吻合,另外挖方厚度越大,土体开挖引起的回弹变形越大;在开挖完成后的1年监测时间内,回弹区变形量随时间呈线性变化,在最大开挖厚度处,产生最大回弹量为29.3 mm;此外,PS-InSAR技术监测到的变形量与实地水准结果吻合性较好,表明该技术在黄土大厚度挖方区回弹变形监测中具有较好的应用效果。 相似文献
338.
Urban system is shaped by the interactions between different regions and regions planned by the government, then reshaped by human activities and residents’ needs. Understanding the changes of regional structure and dynamics of city function based on the residents’ movement demand are important to evaluate and adjust the planning and management of urban services and internal structures. This paper constructed a probabilistic factor model on the basis of probabilistic latent semantic analysis and tensor decomposition, for purpose of understanding the higher order interactive population mobility and its impact on urban structure changes. First, a four-dimensional tensor of time (T)?×?week (W)?×?origin (O)?×?destination (D) was constructed to identify the day-to-day activities in three time modes and weekly regularity of weekday/weekend pattern. Then we reclassified the urban regions based on the space clustering formed by the space factor matrix and core tensor. Finally, we further analysed the space–time interaction on different time scales to deduce the actual function and connection strength of each region. Our research shows that the application of individual-based spatial–temporal data in human mobility and space–time interaction study can help to analyse urban spatial structure and understand the actual regional function from a new perspective. 相似文献
339.
AbstractUrban integration is an increasingly popular phenomenon. It is important to characterize the dynamic processes of urban integration from the perspective of geography. However, previous studies mainly focussed on the overall characteristics of a single entity and failed to consider inter-city influences. Therefore, this study aims to systematically investigate this phenomenon. Firstly, spatial clustering technique and landscape metric were used to analyze the temporal change of spatial layout. Secondly, we built multiple ring buffers of city boundary to reveal the directional differences in urban expansion. Lastly, we compared the observed land use data with the results simulated by cellular automata model. These experiments have shown that the urban expansion characteristics during the urban integration process are rather different from those of a single city, and the above methodology can effectively characterize the urban integration phenomenon. The successful example of Guangzhou–Foshan integration could also provide practical experience for other similar attempts. 相似文献
340.
Space,time, and situational awareness in natural hazards: a case study of Hurricane Sandy with social media data 总被引:1,自引:0,他引:1
Zheye Wang 《制图学和地理信息科学》2013,40(4):334-346
ABSTRACTVarious methods have been developed to investigate the geospatial information, temporal component, and message content in disaster-related social media data to enrich human-centric information for situational awareness. However, few studies have simultaneously analyzed these three dimensions (i.e. space, time, and content). With an attempt to bring a space–time perspective into situational awareness, this study develops a novel approach to integrate space, time, and content dimensions in social media data and enable a space–time analysis of detailed social responses to a natural disaster. Using Markov transition probability matrix and location quotient, we analyzed the Hurricane Sandy tweets in New York City and explored how people’s conversational topics changed across space and over time. Our approach offers potential to facilitate efficient policy/decision-making and rapid response in mitigations of damages caused by natural disasters. 相似文献