机载LiDAR技术

机载LiDAR集成了GPS、IMU、激光扫描仪新一代航空遥感系统,能利用飞行获取的原始数据直接生成DEM和正射影像图,而无需任何或仅需少量的地面控制点。与传统的摄影测量技术相比,机载LiDAR可以节省大量的人力、时间和经费。在过去十年,机载LiDAR作为精确、快速的地球表面三维测量方法已得到广泛的认同,本文详细介绍了机载LiDAR的基本原理、技术结构及数据处理流程。     

土-结构动力相互作用研究综述

土与结构动力相互作用是当代力学领域的前沿性研究课题,具有很强的实践性。对土与结构动力相互作用的研究历史与现状进行了介绍,简要综述了当前土与结构动力相互作用的研究方法,重点介绍了目前关于土与结构动力相互作用问题中从无限域转化成有限域的人工边界研究进展问题,并对该领域今后的研究工作提出了建议。     

"地震数值模拟的数据库应用平台"项目成果介绍

利用计算机模拟复杂的系统和过程,是当今世界科技发展的新潮流,在地学领域,数值模拟已经渗透到地学研究的各个重大领域。本项目提出建立一个用于地震模拟和预报的数据库应用平台,以地壳动力学研究和强震机理研究为应用核心,将地震地质研究、地形变研究、地应力研究、地球内部结构研究等多种相关的学科手段的观测资料、实验结果和理论分析有机地结合起来,实现技术和数据资源的共享。利用这些信息构建比较合理的地球模型和尽可能多的约束条件,并在有限元分析系统上进行地壳形变和地震过程的数值模拟。     

Seismic diagnosis of railway substructures by using secondary acoustic emission

One difficult task for the seismic diagnosis of existing structures is how to nondestructively evaluate the damage degree of invisible substructures, such as embedded foundations. To diagnose substructures efficiently, a method for nondestructive inspection is developed by applying acoustic emission (AE) technique. As a newly proposed method, characteristics of secondary AE induced by train operations were investigated, and experiments using model piles and in-situ AE monitoring of in-service railway bridges conducted under railroad traffic, from which it was demonstrated that the proposed method is practicable enough to detect invisible defects in structures. A new index, known as RTRI (ratio of Repeated Train load at the onset of AE activity to Relative maximum load for Inspection period) is proposed for structural damage qualification based on the results of in-situ AE monitoring.     

Integration of transfer function model and back propagation neural network for forecasting storm sewer flow in Taipei metropolis

Typhoons and storms have often brought heavy rainfalls and induced floods that have frequently caused severe damage and loss of life in Taiwan. Our ability to predict sewer discharge and forecast floods in advance during storm seasons plays an important role in flood warning and flood hazard mitigation. In this paper, we develop an integrated model (TFMBPN) for forecasting sewer discharge that combines two traditional models: a transfer function model and a back propagation neural network. We evaluated the integrated model and the two traditional models by applying them to a sewer system of Taipei metropolis during three past typhoon events (NARI, SINLAKU, and NAKR). The performances of the models were evaluated by using predictions of a total of 6 h of sewer flow stages, and six different evaluation indices of the predictions. Finally, an overall performance index was determined to assess the overall performance of each model. Based on these evaluation indices, our analysis shows that TFMBNP yields accurate results that surpass the two traditional models. Thus, TFMBNP appears to be a promising tool for flood forecasting for the Taipei metropolis sewer system. For publication in Stochastic Environmental Research and Risk Analysis.     

Variations of near-surface atmospheric CO2 and H2O concentrations during summer on Muztagata

Expeditions during the summers of 2002 and 2003 implemented continuous monitoring of near-surface (2 m height) atmospheric CO₂ and H₂O concentrations at the 4500 m elevation on Muztagata. The resultant data sets reveal a slight decrease of CO₂ concentrations (of about 5 μmol·mol^-1) and changes in the diurnal variations from the end of June to the middle August. The daily maximum CO₂ concentrations occur between 02:30-05:30 AM (local time) and the minimum levels occur between 12:00-15:30 PM. The atmospheric CO₂ concentrations in the summer of 2002 were around 5 μmol·mol^-1 lower than those during the same period of 2003, whereas the diurnal amplitude was higher. In contrast, we found that the daily mean atmospheric H₂O content in 2003 was much lower than that in 2002 and there exists a striking negative correlation between CO₂ and H₂O concentrations. We therefore suggest that the near-surface atmospheric CO₂ concentration is affected not only by photosynthesis and respiration, but also by the air H₂O content in the glaciated region around Muztagata.     

日本2006年度地震调查研究项目简介

日本地震调查研究推进本部于2005年8月30日召开第22次本部会议,汇总文部科学省、经济产业省、国土交通省等有关部门的2006年度地震调查研究预算,概算要求总额达131亿日元(不包括独立行政法人等运作经费),比2005年度预算额增加41%。在此之前,地震调查研究本部政策委员会的预算小     

气候生态监测服务系统建设的现状及问题

介绍了气候生态监测服务系统建设的必要性、当前发展的状况和未来趋势.并就存在的问题、今后改进气候生态监测网络建设和加强相关部门间合作、奠定合作基础等问题进行了探讨.     

四川省森林火险预报系统

四川省森林火险预报系统是用VB6.0语言编写,采用多因子线性回归统计方法建立的一套森林火险等级预报业务系统;本系统通用性强、功能齐全,为预报员提供了一套较完备的火险等级预报工具,同时实现了等值线这一科学计算可视化表现方式,摆脱了对专业绘图软件的依赖.     

L波段碳湿敏元件特性试验

目前国内大部分探空站已经启用新一代探空仪——上海长望气象科技有限公司生产的L波段电子探空仪。新探空仪的数据率、测量准确度和可靠性都有较大的提高。新探空仪使用的湿度敏感元件是碳湿敏电阻。我们利用工厂添置的能测到-30℃低温的高精度湿度校准设备，进行了大量静态测试，进一步验证了碳湿敏元件与老探空仪使用的肠衣敏感元件相比，灵敏度高，滞后小，在高空低温期间感应陕，测量准确度有较大提高。