形式化语言在UMTS开发中的应用

由于3G协议规范的复杂性，3GPP方法论指导方针中鼓励使用标准的形式化语言来进行UMTS产品的设计、开发与测试。文中概要性地描述了UMTS的体系结构和在规范描述中用到的一些形式化语言的基本概念和特点，探讨了这些形式化语言在UMTS开发中的应用。使用形式化语言开发UMTS可以简化和改进测试程序，实现新产品与新标准的同步推出。     

三点弯曲下的钢纤维高强混凝土断裂能

通过100个尺寸为100mm×100mm×515mm的不同体积率的钢纤维高强混凝土切口梁三点弯曲试验,探讨了钢纤维体积率和裂缝相对切口深度对高强混凝土断裂能和作用力功的影响。结果表明,钢纤维改善了高强混凝土的断裂性能与延性。钢纤维高强混凝土断裂能增益比、作用力功增益比以及延性指数随着钢纤维体积率的增加而线性增加,随着切口深度的增加而降低;外力功对断裂能的大小起较大作用。在分析试验结果的基础上,建立了钢纤维高强混凝土作用力功和断裂能的计算公式。     

Sediment chemistry and nutrient influx in a hydrologically restored bottomland hardwood forest in Midwestern USA

Exchanges of total N and C between a river and its floodplain forest have been enhanced by sedimentation processes during flood pulses at a 5‐ha bottomland hardwood forest located at the Olentangy River Wetland Research Park in central Ohio. In the spring of 2000, the forest was hydrologically restored by notching an artificial levee that had separated the Olentangy River and its floodplain forest for 100 years. One‐hundred flat sediment traps (30 cm × 30 cm) were used to collect sediment samples during spring/summer flooding events from 2003 to 2005. Results showed that sediment deposition is determined by the landscape variability during flooding events, Net sediment deposit in the wettest area averaged 134 ± 12 g‐dry wt m^?2 in 2003, 127 ± 17 g‐dry wt m^?2 in 2004 and 149 ± 23 g‐dry wt m^?2 in 2005. Total N and C sedimentation ranged from 0.49 to 0.92 g‐N m^?2 and 5.2 to 19.9 g‐C m^?2. Fe dominates the sediment chemistry and results show the elemental abundance in the order of Al > Fe > Ca > K > Mg > S > P > Na > Mn > Zn > B > Cu > Mo. A hydrologic pulsing index (HPI) could be used as an indicator for mass changes of energies with hydrologic pulsing events. Restoration of seasonally flooded bottomland forests could stimulate potentially large nutrient and Fe releases, which would eventually lead to an enhanced forest productivity and biodiversity. Copyright © 2007 John Wiley & Sons, Ltd.     

混凝土坝与坝基互馈面及其确定

基于混凝土坝坝体与坝基互馈作用面的特性，运用优势面理论建立了坝体与坝基互馈优势面的评价指标和分类模型．并以确定三峡工程典型坝段的互馈优势面为例，说明该确定方法简便可行．     

First steps in developing a multimetric macroinvertebrate index for the Ohio River

The causes of degradation of aquatic systems are often complex and stem from a variety of human influences. Comprehensive, multimetric biological indices have been developed to quantify this degradation and its effect on aquatic communities, and measure subsequent recovery from anthropogenic stressors. Traditionally, such indices have concentrated on small‐to medium‐sized streams. Recently, however, the Ohio River Fish Index (ORFIn) was created to assess biotic integrity in the Ohio River. The goal of the present project was to begin developing a companion Ohio River multimetric index using benthic macroinvertebrates. Hester–Dendy multiplate samplers were used to evaluate benthic macroinvertebrate assemblages in relation to a gradient of water quality disturbance, represented by varying distances downstream of industrial and municipal wastewater outfalls in the Ohio River. In August 1999 and 2000, samplers were set every 100 m downstream of outfalls (12 outfalls in 1999, 22 in 2000) for 300–1000 m, as well as at upstream reference sites. Candidate metrics (n = 55) were examined to determine which have potential to detect changes in water quality downstream of outfalls. These individual measures of community structure were plotted against distance downstream of each outfall to determine their response to water quality disturbance. Values at reference and outfall sites were also compared. Metrics that are ecologically relevant and showed a response to outfall disturbance were identified as potentially valuable in a multimetric index. Multiple box plots of index scores indicated greater response to outfall disturbance during periods of low‐flow, and longitudinal river‐wide trends. Evaluation of other types of anthropogenic disturbance, as well as continued analysis of the effects of chemical water quality on macroinvertebrate communities in future years will facilitate further development of a multimetric benthic macroinvertebrate index to evaluate biotic integrity in the Ohio River. Copyright © 2007 John Wiley & Sons, Ltd.     

水利规划生态适宜性研究

选择生物丰度指数、植被覆盖指数、水资源指数、土地退化指数、污染负荷指数5类基本因子，组成生态适宜性评价指标，评价值在0．067-1．500之间变化，对结果进行再处理、聚类，划分毗河供水规划的生态适宜分区。结合区域生态、环境特征和要求，对水利规划作出相应的调整。毗河供水规划整体布局较合理，大型建设项目未处于生态需特别保护的区域。各水库农业灌溉的同时，也能发挥生态功能，为周围环境提供用水，对区域生态与环境有促进作用。     

Data mining of resilience indicators

In recent years, the Asia-Pacific region has experienced several financial setbacks, including speculative attacks in 1998 and the SARS outbreak in 2003. Financial stresses of this nature are unanticipated, and not all of the dangers can be predicted by the examination of market information and macroeconomic indicators. The Early Warning System (EWS) that has been adopted by the International Monetary Fund may not be able to predict future financial crises for all possible scenarios, because shocks come in many different forms. To supplement the EWS, this paper proposes a data mining framework to measure the resilience of an economy. The resilience framework does not predict a crisis, but rather assesses the current state of health of an economy and its ability to withstand a financial shock should one occur. The framework is based on a feedback system consisting of two stages. The first stage assigns a resilience score to each economy based on a fuzzy logic scoring scheme that is built on the ambiguous reasoning of experts. The second stage uses the classification tree approach to estimate thresholds for each economic indicator, and examines the quality of the fuzzy score. The result from the second stage is then passed back to the first stage as feedback. The final result is obtained when the feedback system reaches its equilibrium state. The proposed resilience framework is applied to the external-sector and the public-sector economies of several countries to illustrate its applicability.     

基于关键节点和多播节点的多播路由算法

在视频会议等多播应用中，降低多播树网络费用非常重要。本文提出了基于关键节点和目的节点的多播路由KDDMC算法。由于在算法中优先考虑采用关键节点，实现更多链路的共享，从而降低网络费用。在随机网络上的仿真结果表明，KDDMC算法的多播树网络费用优于SPH算法。同时证明了KDDMC算法的复杂度为O(n^3)，且利用所提出的路由表算法易于分布式实现。     

DB2数据库查询优化策略

数据库的查询优化是改善应用程序性能的重要手段。通过分析IBM DB2数据库系统的最优化处理器的工作原理,对查询性能影响较大的统计信息更新、索引建立、SQL查询语句构造3个方面提出具体优化建议。建立了一套完整的测试方案,对每一条优化建议都使用具体SQL语句进行严格的验证。开发者要注意分析查询语句的时间开销和空间开销,才能写出较优的查询语句。     

一种增强型冲突分解算法

冲突分解算法是一种能有效改善无线信道多址接入协议的方式。本文对传统的冲突分解算法——树形冲突分解算法和先到先服务冲突分解算法进行了深入研究和仿真，探讨了这两种算法的优点和不足之处，提出了一种增强型的冲突分解算法（Enhanced Splitting Algorithm，ESA）。该算法继承了树形冲突分解算法和先到先服务算法的优点，不仅考虑了碰撞分组产生的时间，还考虑了分组的产生间隔，从而有效地提高了冲突分解算法的性能。仿真结果显示ESA算法是一种可行的算法。