波浪冲击过程流场变化特性试验研究     

任冰  李雪临  王永学 《海洋工程》2006,24(4):68-74

利用瞬态全场测量技术———粒子图像测速(PIV)技术,研究了波浪对透空式建筑物上部结构冲击过程的流场变化特性。通过对采集到的CCD图像互相关分析,直观地显示了波浪冲击作用发生时结构物底面的流场状态,得到瞬间全场流体水质点速度矢量,并且应用概率分析法研究了冲击压力峰值与波浪水质点运动速度之间的关系。  相似文献   

顾及形变的影像边缘ICP匹配技术     

高力  金飞  江振治  王番  芮杰 《测绘通报》2019,(12):40-44

匹配技术是遥感影像处理中的重要基础技术,影像在辐射、几何信息方面的差异,将会严重干扰影像间的相似特征匹配。本文提出了针对大差异影像的最邻近点迭代匹配算法（ICPDI）。首先改进Canny算子的参数设置方式,以便选择影像的长边缘作为影像匹配的显著特征;然后以线特征之间的距离作为影像相似性的评估标准,达到利用全局相似特征抑制局部差异的目的;最后给影像边缘附加形变函数,从而扩展ICPDI匹配技术的适用范围。通过不同差异类型遥感影像间的匹配试验,验证了本文方法的精度和适应性。  相似文献   

Calculating vertical deformation using a single InSAR pair based on singular value decomposition in mining areas     

《International Journal of Applied Earth Observation and Geoinformation》2020

Vertical deformation estimation can be a significant tool in preventing geological hazards and managing environment impacts of underground mining. Common ground surface vertical deformation calculations are challenged by difficult data collection and dependence on prior knowledge. SVD (singular value decomposition) method was applied to estimate ground surface vertical deformation from single pair SAR (synthetic aperture radar) data in a mining region. During the study, LOS (line of sight) and azimuth displacement was obtained using two pass D-InSAR (differential interferometry synthetic aperture radar) and MAI (multi-aperture radar interferometry) technology, respectively. Two adjustment equations were composed using the imaging geometry of D-InSAR and MAI. The singular value decomposition theorem was used to acquire M-P (Moore-Penrose) generalized inverse of the rank deficiency coefficient matrix. From this, the optimal approximation solution of unknown parameters was calculated using weighted least squares. A working panel in the Datong mining area, Shanxi province, China, was selected to verify the SVD approach using the two ascending Sentinel-1A data. The accuracy of vertical deformation estimated by SVD approach is reliable. The RMSE (root mean square error) of vertical deformation is 2.64 mm (along upright profile) and 4.95 mm (along horizontal profile). These results suggest that the SVD approach will complement widely used vertical ground surface deformation calculations. Further study is needed to validate the method from other deformation scenarios from landslides, groundwater loss, earthquakes, underground mining, and glacier movement.  相似文献   

Spatial autocorrelation of West Nile virus vector mosquito abundance in a seasonally wet suburban environment     

P. R. Trawinski  D. S. Mackay 《Journal of Geographical Systems》2009,11(1):67-87

The objective of this study is to quantify and model spatial dependence in mosquito vector populations and develop predictions for unsampled locations using geostatistics. Mosquito control program trap sites are often located too far apart to detect spatial dependence but the results show that integration of spatial data over time for Cx. pipiens-restuans and according to meteorological conditions for Ae. vexans enables spatial analysis of sparse sample data. This study shows that mosquito abundance is spatially correlated and that spatial dependence differs between Cx. pipiens-restuans and Ae. vexans mosquitoes.   相似文献   

基于奇异谱分析的江淮降水场预测模型研究   总被引：4，自引：1，他引：3  

章毅之 《气象与减灾研究》2006,29(1):34-37

中国的降水预报主要是对汛期(夏季)的单站降水量或区域的降水型态进行预报,而主要的预报方法为动力学方法和统计学方法。据此,利用江淮地区的月降水量标准化序列,得到江淮地区降水时空分布型态。并在此基础上,利用奇异谱分析和时间序列的分析方法,设计了统计学的降水预测模型,对江淮地区的月降水量进行了预测试验。结果表明,模型能对江淮降水场的趋势作出较好的预报,且递推时间短时预报效果较好。  相似文献