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991.
Application of horizontal-to-vertical (H/V) Fourier spectral ratio for analysis of site effect on rock (NEHRP-class B) sites in Taiwan 总被引:1,自引:0,他引:1
Vladimir Yu. Sokolov Chin-Hsiung Loh Wen-Yu Jean 《Soil Dynamics and Earthquake Engineering》2007,27(4):314-323
The frequency-dependent amplification for rock (NEHRP-class B) sites was studied using earthquake ground-motion database collected in Taiwan during implementation of the Taiwan Strong Motion Instrumentation Program. The database used includes several hundred records from earthquakes of ML 4.0–7.3 occurred between 1993 and 2004. The characteristics of amplification were evaluated using the well-known technique of horizontal-to-vertical Fourier spectral ratio (H/V) of the S-wave phase [Lermo J, Chavez-Garcia FJ. Site effect evaluation using spectral ratios with only one station. Bull Seism Soc Am 1993;83:1574–94]. The study allows us to analyze peculiarities of rock sites amplification in Northern and Eastern Taiwan. It was suggested to divide the NEHRP-class B site amplification into four types based on frequency of maximum amplification and the shape of amplification function. The applicability of the technique was also checked for a few stiff and soft soil sites (NEHRP-classes D and E). 相似文献
992.
S. Abhilash Someshwar Das S. R. Kalsi M. Das Gupta K. Mohankumar John P. George S. K. Banerjee S. B. Thampi D. Pradhan 《Pure and Applied Geophysics》2007,164(8-9):1491-1509
Pre-monsoon rainfall around Kolkata (northeastern part of India) is mostly of convective origin as 80% of the seasonal rainfall
is produced by Mesoscale Convective Systems (MCS). Accurate prediction of the intensity and structure of these convective
cloud clusters becomes challenging, mostly because the convective clouds within these clusters are short lived and the inaccuracy
in the models initial state to represent the mesoscale details of the true atmospheric state. Besides the role in observing
the internal structure of the precipitating systems, Doppler Weather Radar (DWR) provides an important data source for mesoscale
and microscale weather analysis and forecasting. An attempt has been made to initialize the storm-scale numerical model using
retrieved wind fields from single Doppler radar. In the present study, Doppler wind velocities from the Kolkata Doppler weather
radar are assimilated into a mesoscale model, MM5 model using the three-dimensional variational data assimilation (3DVAR)
system for the prediction of intense convective events that occurred during 0600 UTC on 5 May and 0000 UTC on 7 May, 2005.
In order to evaluate the impact of the DWR wind data in simulating these severe storms, three experiments were carried out.
The results show that assimilation of Doppler radar wind data has a positive impact on the prediction of intensity, organization
and propagation of rain bands associated with these mesoscale convective systems. The assimilation system has to be modified
further to incorporate the radar reflectivity data so that simulation of the microphysical and thermodynamic structure of
these convective storms can be improved. 相似文献
993.
Michael H. Cosh Jery R. Stedinger Steve C. Ou Kuo-Nan Liou Wilfried Brutsaert 《Advances in water resources》2007
This study focuses on how the variability of land surface temperature and vegetation density at the SGP ARM-CART site changes over episodic (day to day) and seasonal time scales using AVHRR satellite data. Four drying periods throughout the year are analyzed. Land surface temperature had an erratic relationship with time exhibiting no deterministic pattern from day-to-day or season-to-season. Furthermore, it did not exhibit spatial pattern persistence. On the other hand, vegetation density had a consistent spatial pattern and temporal decay during average length drying periods (less than 7 days) as well as within a season. However, there were distinct differences in the seasonal pattern of variation between winter and growing seasons. In addition, the paper highlights a methodology to quantify the relationships that exist at the land surface between the primary parameter of interest and the controlling variables. 相似文献
994.
This paper presents a new method, called the equivalent force control method, for solving the nonlinear equations of motion in a real‐time substructure test using an implicit time integration algorithm. The method replaces the numerical iteration in implicit integration with a force‐feedback control loop, while displacement control is retained to control the motion of an actuator. The method is formulated in such a way that it represents a unified approach that also encompasses the effective force test method. The accuracy and effectiveness of the method have been demonstrated with numerical simulations of real‐time substructure tests with physical substructures represented by spring and damper elements, respectively. The method has also been validated with actual tests in which a Magnetorheological damper was used as the physical substructure. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
995.
Eric J.E. Molin Harmen Oppewal Harry J.P. Timmermans 《Journal of Geographical Systems》2002,4(4):343-358
In this paper, two approaches for measuring residential group preferences, based on the method of Hierarchical Information
Integration (HII), are compared. In particular, the hypothesis that group-based preference models estimated from integrated
HII experiments better predict group preferences than part individual-based group models estimated from classical HII experiments
is tested. To that effect, the models' ability to predict group preferences for new residential alternatives is compared in
a study of residential preferences of co-ops. Results indicate that integrated HII group experiments indeed result in better
predictions of residential preferences. 相似文献
996.
简要介绍了一种GIS平台SICAD/Open,详细描述了SICAD/Open空间拓扑结构,给出了基于SICAD/Open空间拓扑结构的地籍空间实体图形变更处理方法,为在地籍信息系统中利用地理信息系统技术实现地籍空间实体图形变更提供了一种切实可行的操作方法。文中描述的处理方法已成功应用于上海市地籍管理信息系统中。 相似文献
997.
空间数据仓库研究综述 总被引:7,自引:0,他引:7
论述了空间数据仓库的定义、基本特征;着重叙述了目前国内外空间数据仓库在学术研究、产品研制和实际应用方面的发展现状;设计出了空间数据仓库的体系结构,说明了空间数据仓库和应用系统的区别与联系;最后得出结论,为支持我国空间数据基础设施建设,研制空间数据仓库十分必要。 相似文献
998.
999.
1000.
海量数据CDT快速建立及其实时更新 总被引:3,自引:0,他引:3
对海量地形数据快速整体CDT生成、实时更新等算法进行了研究,并在AutoCAd环境下研制了公路数字地面模型软件BID-Land,实现了与公路CAD的集成。190多公里国家重点公路工程勘察设计中的实际应用表明,程序算法具有很强的实用性、极高的效率和良好的地形模拟精度。 相似文献