嘉陵江流域洪水等级的建议划分标准

根据洪水重现期可以将洪水划分为12个等级,也可根据年最大流量距平值将洪水中长期定性预报分成7个等级.探讨了嘉陵江流域的洪水等级和中长期预报定性分级标准,还对嘉陵江流域1981年7月发生的洪水等级进行了分析.     

Evaluating Visitor-Monitoring Techniques: A Comparison of Counting and Video Observation Data

Two visitor-monitoring methods, video monitoring and counts by human observers, were compared in order to identify and evaluate their respective advantages and disadvantages. The analysis considered user numbers, user type (walkers, dog walkers, bicyclists, and joggers) and group size of visitors. Remarkable differences were found between the two methods for user type and use levels. At low use levels, evaluations based on video monitoring resulted in fewer single bicyclists compared to counts by human observers, whereas at high use levels, human observers counted fewer walkers and bikers than video-interpreters. Based on this comparative analysis, we derive recommendations for more effective visitor-monitoring approaches. All data were collected during a visitor-monitoring project in the Danube Floodplains National Park in Austria between 1998 and 1999.     

重庆大气微生物污染状况调查与评价

本文在对重庆大气微生物污染含量调查的基础上，评价分析了重庆大气微生物的污染状况。调查结果表明：城区大气微生物污染高于区县；并分析了霉菌污染普遍性的原因。     

REGION OF INFLUENCE REGRESSION FOR ESTIMATING THE 50-YEAR FLOOD AT UNGAGED SITES1

ABSTRACT: Five methods of developing regional regression models to estimate flood characteristics at ungaged sites in Arkansas are examined. The methods differ in the manner in which the State is divided into subregions. Each successive method (A to E) is computationally more complex than the previous method. Method A makes no subdivision. Methods B and C define two and four geographic subregions, respectively. Method D uses cluster/discriminant analysis to define subregions on the basis of similarities in watershed characteristics. Method E, the new region of influence method, defines a unique subregion for each ungaged site. Split-sample results indicate that, in terms of root-mean-square error, method E (38 percent error) is best. Methods C and D (42 and 41 percent error) were in a virtual tie for second, and methods B (44 percent error) and A (49 percent error) were fourth and fifth best.     

不确定条件下的区域能源-大气系统优化模型

以北京市丰台区能源-大气系统为实际案例,结合区间机会约束规划方法,以区间参数和随机参数反映系统的不确定信息,以能源系统总成本最小化为目标函数,以能源供需、热电生产、新能源消费、大气污染物排放等为主要约束条件,建立了区域能源-大气优化模型。通过交互式算法,确定了不同风险水平下的优化方案。研究结果表明:丰台区将建立以天然气为主要能源载体,燃气发电供热为主,新能源发电供热为补充的多元化能源系统。     

基于交通安全的交叉口倒计时信号灯设置研究

交通信号倒计时装置被国内一些城市广泛采用。在体现交通“以人为本”原则的同时,倒计时装置的应用也应注意其带来了一些交通安全和通行效率上的问题。倒计时会诱发一部分驾驶员在绿灯末尾时加速通过路口,和红灯变绿灯下一相时头车提前高速到达冲突点,可能引发重特大交通事故,因而需要更长的绿灯间隔时间保证信号换相时的交通安全。由于绿灯间隔时间增长,交通信号倒计时装置降低了交叉口的通行能力,且不当的绿间隔设置还会造成严重的交通冲突。因而应谨慎采用机动车交通信号灯倒计时装置,并应辅以绿灯间隔时间调整、交通安全宣传教育和明确交通规则等措施。     

洪水等级的划分方法

分析了洪水要素的多样性和洪水的复杂性，提出了利用洪水重现期划分洪水安全度等级和利用标准面积洪峰流量划分洪峰标准等级的两种方法，并对1998年长江流域的洪水等级进行了简要分析。     

路基沉降的非等间隔时变离散灰色预测模型

本文分析了灰色GM(1,1)模型的缺陷,并以离散GM(1,1)模型为基础建立了路基沉降的非等间隔时变离散灰色预测模型,该模型参数以最小二乘法估计,且以遗传算法优化初始值,通过工程实例与不同预测模型进行对比分析,结果表明非等间隔时变灰色预测模型的精度明显高于其他模型,且最能反映原始路基沉降数据的发展规律.     

基于MATLAB的湘江流域工业固体废物灰色预测

对灰色预测原理及其建模步骤作了系统介绍。借助MATLAB软件建立等维灰数递补残差修正动态模型预测湘江流域未来10年工业固体废物年产量,以期为湘江流域今后工业固体废物的管理、污染防治工作提供科学依据。结果表明:(1)用此模型进行预测,相对误差均在5%以下,预测精度较高,取得了较理想的预测效果;(2)湘江流域未来10年工业固体废物年产量预测值呈指数趋势增长,年增长率为8%～12%,到2016年湘江流域工业固体废物年产量预计将达到7645.01万t。