基于PKI/CA技术的铁路身份认证体系

通过对铁路行业已有的CA认证平台的分析,指出其中认证技术和建设模式存在的问题和不足,结合铁路信息系统的实际情况和行业自身的特点,构建了由铁路行业根CA、CA认证中心和RA管理中心组成的铁路行业统一认证体系,提出铁路行业CA中心的建设应采用完全自建的模式,并采用铁道部和铁路局两级分别构建的结构的方式,对认证中心的建设方案、功能和组成进行了分析。

CA认证系统在统计局中的应用

CA认证系统用于数字证书的申请、审核、签发、注销、更新、查询的综合管理系统。通过CA认证中心发行的电子证书可以为用户提供信息安全的全面服务。CA认证系统拥有高强度的加密算法 ,高可靠性的安全机制及完善的管理及配置策略 ,提供自动的密钥和证书管理服务。

Estimation of peak runoff and frequency in an ungauged stream of a forested watershed for flood hazard mapping

Kaynasli District in the western Black Sea region of Turkey has long been vulnerable to frequent flood damage due to the establishment of settlements within and around stream channels without regard to fluctuating peakstreamflow frequencies. The aim of this research was to determine the measures needed to protect the towns and villages from this type of damage. Daily total precipitation data for 1975–2010 were analysed, and rainfall-runoff models developed to estimate the potential yearly maximum discharge from each stream of sub-watersheds dominated by forests and/or agriculture. This was then calculated for different frequencies of the yearly maximum discharge. Flood analysis and mapping was modified via the one-dimensional Hydrologic Engineering CentersRiver Analysis System software to produce potential maximum discharge and geometric data for Kaynasli Creek. As the main creek of the sub-watershed, its crosssection was shown to be insufficient and incapable of containing the maximum discharge at the 100-year frequency presumed for the watershed, and subsequently was seen as having a high level of casualty risk. It was concluded that the one dimensional model could be useful, but 2D models were more suitable for these types of watersheds.

基于物理机制的分布式水文模型对三峡区间径流的模拟

基于物理机制的分布式水文模型是无水文资料区域的径流模拟的一种有效手段,在对模拟效果的评价中,区间流域水文资料的短缺成为限制条件。针对此问题,该文以三峡区间径流模拟的效果评价为实例,借助区间模拟入流对干流洪峰的模拟作用,对其进行分析和评价。基于三峡区间GBHM（geomorphology-based hydrological model）分布式水文模型,模拟1989~2000年期间的区间径流,为三峡库区河道的HEC-RAS（hydrologic engineering center-river analysissystem）洪水演进模型提供侧向入流资料。比较计入和不计入区间模拟径流2种情况下库区河道洪峰流量的模拟误差,分析GBHM水文模型对区间径流的模拟效果。结果表明：在库区河道洪峰中区间径流占50%的洪水场次中,基于GBHM模型模拟的区间径流,可使洪峰的模拟精度提高到90%以上。基于物理机制的分布式水文模型对三峡区间径流的模拟,具有明显的作用。