XML文档流上的一种关键字查询方法研究

本文将当前数据库领域的2个研究热点-XML文档和数据流处理一的最新研究结合起来,提出了XML文档流关键字查询的问题。基于最小连通子树的概念。设计了相应的数据结构和基于栈的查询算法,可以有效解决XML文档流上进行关键字查询的问题。具体方法是把XML数据流表示成3类SAX事件：BEGIN（tag）、END（tag）和TEXT0。对每类事件的处理算法进行了详细,并进行了正确性证明。从理论上分析了算法的复杂度,并在XMark和treebank．xml两个数据集上对所提方法进行了广泛的实验。结果验证了本文工作的有效性。     

使用FTAM协议实现话务数据的联机实时采集

对FTAM传输协议和交换机内部产生实时呼叫记录的机制进行研究,介绍了一种利用OSI协议栈,FTAM API编程接口实现联机话务数据的实时采集系统。针对移动交换机两种常用的话务数据传输接口（802．x与X．25）,对其OSI协议栈中底层协议的各自特点进行了对比分析。     

A CLIMATE‐BASED INDEX OF HISTORIC SPAWNING‐STREAM HYDROLOGY

Reproductive success of stream‐spawning Oncorhynchus fishes (Pacific salmon, rainbow trout, cutthroat trout and their allies) may be greatly affected by stream discharge or its covariate, stream temperature, during the spawning season. Because such data for the physical environment may not have been routinely collected as part of previous investigations of these fishes, identification of simple but robust indices of historic, seasonal stream discharge and temperature, using long‐term climate data sets, would be important, especially to investigations of historic population dynamics. This study examined statistical associations among several climate variables and the spawning‐season (approximately June) discharges and temperatures of Clear Creek, a Yellowstone Lake tributary used by spawning Yellowstone cutthroat trout, Oncorhynchus clarkii bouvieri (YCT), from the lake. Correlation analysis showed that total water‐year degree‐days (calculated on the basis of mean daily air temperature > 0°C) at Lake Village, on the lake's north shore, was a robust index (both negative and positive, respectively) of consecutive, total semi‐month metrics of creek discharge and temperature during the YCT spawning season. This study (and subsequent use of the Lake Village degree days metric as an environmental variable in a dynamic, age‐structured model of the lacustrine–adfluvial YCT population of Clear Creek) showed how exploratory analyses of the fragmentary but long‐term and regionally unique data sets for Clear Creek discharge and temperature revealed a simple but robust index of climate variation important to understanding the historic dynamics of Clear Creek's YCT population, which is a key spawning stock of Yellowstone Lake. In addition, the extensive statistical associations among the climate variables, along with the temporal trends in two key variables, broadly showed how climate varied across the Yellowstone Lake region during the past several decades. Those observations have implications for the historic, seasonal hydrology of all Yellowstone Lake tributaries used by spawning YCT. Copyright © 2011 John Wiley & Sons, Ltd.     

Trivium型级联反馈移存器的非奇异性判定

Trivium算法是eSTREAM工程最终胜出的面向硬件实现的序列密码算法之一.对以该密码算法为特例的Trivium型级联反馈移存器,研究了其非奇异性判定,给出了有限域上Trivium型级联反馈移存器非奇异的充分条件和二元域上Trivium型级联反馈移存器非奇异的充要条件,并证明了Trivium算法在初始化阶段和密钥流生成阶段的状态刷新变换都是双射.     

CREATING AND EVALUATING DIGITAL ELEVATION MODEL‐BASED STREAM‐POWER MAP AS A STREAM ASSESSMENT TOOL

As urban development increases, a need is emerging to understand and predict river behaviour in order to focus rehabilitation efforts and protect the natural river system while preserving urban infrastructure. Stream assessment methods are reviewed to demonstrate the need for a physically based and objective method that is also accessible in terms of time, data requirements and expertise. The case of Highland Creek near Toronto, Canada, is used to demonstrate a new type of initial stream assessment method that is based on the concept of stream power and performed entirely in a geographic information system using information from a digital elevation model (DEM). The results from this analysis are tested against existing information for Highland Creek. This includes a hydraulic model (Hydraulic Engineering Center's ‘River Analysis System’), field‐measured slopes, air photos and the geomorphic effects of an extreme flood. In addition, the results are presented in map form to demonstrate the effectiveness of visualizing the stream‐power distribution over the entire basin and also the usefulness of overlaying stream power onto other available information. The slopes extracted from the DEM are found to be statistically similar to those from a one‐dimensional hydraulic model and field‐measured slopes. Individual peaks in slope as well as locations of stream‐power maxima and minima are found to correlate to actual channel features as seen in air photos. The extreme flood event of August 2005 caused a dramatic change in channel form at the exact location of maximum energy predicted by the DEM‐based stream‐power analysis. The case of Highland Creek illustrates how this approach yields a useful outcome for understanding stream dynamics and stability as part of a stream assessment process. Copyright © 2011 John Wiley & Sons, Ltd.     

黄河小北干流河段揭河底规律分析

“揭河底”现象是黄河高含沙洪水特有的一种泥沙运动方式.本文通过对历史“揭河底”水文资料的统计和分析,提出了历史“揭河底”发生的水沙条件、河道边界条件、河床淤积物组成,总结了其发生的规律.该研究进一步探讨了黄河小北干流河段“揭河底”冲刷现象的运动机理,充分发挥冲刷塑造窄深河槽的积极作用,减小了冲刷造成的危害,对在治黄中如何利用“揭河底”规律,趋利避害有一定的指导意义.     

基于可控蒸散发的狭义水资源配置

以流域"天然-人工"二元水循环模式和水资源优化配置模型为基础,构建针对区域目标蒸散发(ET)的狭义水资源评估模型。结合流域分区经济耗水和生态耗水计算方法,给出评估模型分析过程,提出基于可控ET的水资源可持续利用评价指标。以湟水干流为例,利用针对区域目标ET的狭义水资源评估模型,阐述当地近5 a水资源开发利用过程中存在的问题,为社会经济发展规划和水资源配置格局提供建议。实例应用表明,基于区域目标ET的狭义水资源评估模型,可为流域分区的水资源配置和管理提供依据。     

基于逆建模技术的淮河干流长台关-息县段入河污染负荷评估

以淮河上游长台关-息县段为研究对象,以2008年为算例,根据研究区域汇流特征,建立分布式源模型,基于贝叶斯统计方法进行逆建模,利用断面水质序列实测资料,测算区域入河污染负荷及主要水质因子降解系数。结果表明:淮河上游长台关-息县段NH3-N、COD入河污染负荷总量分别为1.7万t/a、8.9万t/a;受主要入流面源污染负荷季节性影响,NH3-N入河污染负荷为657.55～2 014.99 t/月,COD入河污染负荷为3897.73～13311.83 t/月;研究区域水体环境NH3-N、COD降解系数分别为0.356/d、0.202/d,NH3-N、COD负荷模拟值和实测值的相关系数分别为0.943、0.979。     

冰山理论下的《乞力马扎罗山上的雪》

海明威的创作具有＂冰山风格＂,《乞力马扎罗山上的雪》就是海明威笔下一篇浓缩了的长篇小说,是体现其冰山理论的代表作。小说中雪、豹子、秃鹫和鬣狗等意象各具意蕴,象征意义深刻,揭示了人物的性格特征,渲染了气氛,达到了深化主题的目的。作者通过对意识流叙事手法的运用,巧妙安排了主人公的意识在时间和空间里的自然流动,省去了大量的笔墨,有利于海明威＂冰山风格＂创作理论的运用。     

pn 周期序列3错线性复杂度原序列计数公式

k错线性复杂度作为密钥流序列稳定性的重要指标,对于衡量密钥流序列密码强度具有十分重要的意义,研究具有高k错线性复杂度的序列也一直是序列密码中的热点问题。该文在XWLI算法基础上,给出k错线性复杂度小于等于pn-1时pn周期二元序列的3错线性复杂度的原序列计数公式,并通过实例验证了该文理论的正确性和合理性,该文方法同样适用于研究pn 周期q元序列的计数。