上海市不同历时暴雨组合概率研究

基于上海市徐家汇站1960—2011年的日降雨资料,分析上海市年最大1d和3d降水量年际变化和年代际变化特性;择优选择GH Copula函数构建了年最大1 d与3 d降水量的联合分布模型,并推算它们的同现重现期和组合风险概率。结果表明:年最大1 d和3 d降水随时间呈增加趋势,自20世纪70年代开始其均值随年代增加;年最大1 d和3 d设计暴雨同频遭遇风险率在75%~85%之间,且同现风险率随年最大1 d设计暴雨值增大而增加。在设计上海市防洪排涝标准时若考虑最大1 d和3 d降水量的遭遇组合,有利于提升防洪排涝能力,保障防洪安全。     

认真贯彻中央一号文件推动广西农村水利改革发展

通过学习贯彻中央一号文件,分析揭示当前农村水利发展面临的主要矛盾和重大机遇,提出新时期广西农村水利改革发展的工作思路、目标和主要任务.     

湖北省水环境遥感监测示范系统的设计与应用

介绍基于环境一号卫星(HJ-1)CCD影像的湖北省水环境遥感监测示范系统的设计与应用。该示范系统以环境一号卫星CCD影像为主要数据源,结合地面实测数据,以东湖、梁子湖等10个湖泊为示范研究区,开展中小型湖泊湖网系统水环境遥感监测研究与应用。结果表明,该系统具有实现水环境指标提取、水环境评价以及专题产品制作等功能,可为湖北省水环境监测提供遥感产品与技术支持。     

基于物理过程的分布式流域水沙预报模型

将分布式水文模型与土壤侵蚀产沙模型相互嵌套,构建了一个分布式流域水沙预报模型。模型基于DEM,将流域离散为“坡面+ 沟道”系统,采用“+ 1 ”分级方法将沟道组织为河网,实现了流域水沙预报的并行计算。坡面单元划分为植被层、地表层、非饱和带和地下水层,模拟了降雨、截留、蒸散发、入渗、地表径流、壤中流和地下水、各种形式的侵蚀产沙及泥沙输移;沟道进行汇流演算以及泥沙输移。模型在李子溪流域对长系列降雨的模拟结果表明,模型的水文模块模拟精度良好,侵蚀产沙模块模拟效果基本令人满意。     

Extended activated sludge model no. 1 (ASM1) for simulating biodegradation process using bacterial technology

Phosphorus is one of the most important nutrients required to support various kinds of biodegradation processes. As this particular nutrient is not included in the activated sludge model no. 1 (ASM1), this study extended this model in order to determine the fate of phosphorus during the biodegradation processes. When some of the kinetics parameters are modified using observed data from the restoration project of the Xuxi River in Wuxi City, China, from August 25 to 31 in 2009, the extended model shows excellent results. In order to obtain optimum values of coefficients of nitrogen and phosphorus, the mass fraction method was used to ensure that the final results were reasonable and practically relevant. The temporal distribution of the data calculated with the extended ASM1 approximates that of the observed data.     

我国的M1/M2(1978-2002):长期趋势、水平与周期波动

本对我国1978—2002年的M1／M2的长期趋势、水平和周期波动进行了研究，结果表明1978—1995年，中国的M1／M2呈急剧下降的态势，但是从1996至今则基本保持平稳。另外从国别比较来看，我国属于M1／M2比较高的国家(地区)之一，这表明我国的居民和企业由于支付制度、取款成本、规避税收等原因比美、日等国家的经济主体对M1的需求高很多。除开长期走势之外，中国的M1／M2还伴随着经济活动呈周期性的波动，实证分析结果表明1996年前的经济增长率是M1／M2周期波动的Granger原因，但1996年以后则必须由名义利率、通货膨胀率和股票市场交易量的变动才能说明M1／M2的波动。     

Long term dependence in stock returns

We show, using the modified rescaled range statistic, that none of the return series of indices of five European countries, the United States and Japan exhibits long term dependence. This statistic — introduced by Lo (1991) — correct Hurst's (1951) ‘classical’ rescaled range statistic for short term dependence. We also report the classical rescaled range statistic after adjusting the series for short term dependence. This procedure shows, for cases where the results of the modified rescaled range statistic are mixed, that no long term dependence can be found. Simulations indicate reasonable power of this adjustment procedure. Furthermore, we find that estimates of the Hurst exponent, a related measure of long term dependence, are also biased by short term dependence. Simulations show that this measure — that has recently attracted growing interest — cannot distinguish between models with or without long term dependence.     

Currency competition: A partial vindication of Hayek

This paper establishes the existence of equilibria for environments in which outside money is issued competitively. Such equilibria are typically believed not to exist because of a classic overissue problem: if money is valued in equilibrium, an issuer produces money until its value is driven to zero. By backward induction, money cannot have value in the first place. This paper shows that overissuance is not a problem if agents believe that if an issuer produces more than some threshold number of notes, then only those notes issued up to the threshold will be valued; additional notes will be worthless. This result is very general, applying to any monetary economy in which equilibria with and without valued money exist if the money supply is finite. The paper also compares the allocation achieved by a monopolist to that achieved with competitive issuance in both a search and an overlapping-generations environment. The results depend on the environment considered, but two general conclusions arise. First, it is ambiguous whether competitive issuers can achieve a more desirable allocation than a monopolist. Second, with competitive issuance, a licensing agency can always improve on pure laissez-faire and achieve the efficient allocation in the long run.     

The macroeconomic consequences of terrorism

We perform an empirical investigation of the macroeconomic consequences of international terrorism and interactions with alternative forms of collective violence. Our analysis is based on a rich unbalanced panel data set with annual observations on 177 countries from 1968 to 2000, which brings together information from the Penn World Table data set, the ITERATE data set for terrorist events, and data sets of external and internal conflict. We explore these data with cross-sectional and panel growth regression analysis and a structural VAR model. We find that, on average, the incidence of terrorism may have an economically significant negative effect on growth, albeit one that is considerably smaller and less persistent than that associated with either external wars or internal conflict. As well, terrorism is associated with a redirection of economic activity away from investment spending and towards government spending. However, our investigation also suggests important differences both regarding the incidence and the economic consequences of terrorism among different sets of countries. In OECD economies, in particular, terrorist incidents are considerably more frequent than in other nations, but the negative influence of these incidents on growth is smaller.     

Macroeconomic consequences of terror: theory and the case of Israel

This paper analyzes the effect of terror on the economy. Terror endangers life such that the value of the future relative to the present is reduced. Hence, due to a rise in terror activity, investment goes down, and in the long run income and consumption go down as well. Governments can offset terror by putting tax revenues into the production of security. Facing a tide in terror, a government that acts optimally increases the proportion of output spent on defense, but does not fully offset the tide. Thus, when terror peaks the long run equilibrium with an optimizing government is of lower output and welfare. Next, we show that this theory of terror and the economy, helps to understand changes in trend and business cycle of the Israeli economy. The estimates show that terror has a large impact on the aggregate economy. Continued terror, at the level of the death toll by about the same size as due to car accidents, is expected to decrease annual consumption per capita by about 5% in 2004. Had Israel not suffered from terror during the last 3 years, we estimate that the output per capita would have been 10% higher than it is today.