“94.6”特大暴雨洪水初步分析

9403号台风后,华南地区6月上、中旬普降暴雨,大暴雨、局部特大暴雨,造成珠江流域西、北江中下游并发超50年一遇大洪水,两江洪峰几乎同时到达思贤滘,此时又处在潮水上涨期,西北江三角洲水位在洪湖共同作用下迅猛上涨,部分水位站达到50～100年一遇,给两广带来严重的灾害。本文在阐述流域概况基础上,分析了天气系统暴雨时空分布和暴雨洪水特点,分别论证北江洪水、西江洪水及西北江三角洲洪水情况,供有关部门参考。     

Success breeds success. The dynamics of the innovation process

This paper presents a dynamic random effects probit model for the realization of private firms' product and process innovations. We estimate the model with panel data collected by the Ifo Institute in Munich. The data covers the period between 1979 and 1986 and includes 301 firms of the West German manufacturing sector. It turns out that firms' probabilities of innovation depend on market structure, demand and cost expectations, unobserved heterogeneity, and realized innovations in the previous year. The positive significant influence of past innovations indicates that there is strong state dependence in the innovation process. This result supports the success breeds success hypothesis suggesting a positive impact of innovative success to further innovations in the following years.We would like to thank the Ifo-Institute for providing us with the data of the Ifo-Konjunkturtest. Special thanks to Georg Licht and Horst Rottmann for preparing the data. Helpful comments were received from participants of seminars in Mannheim, Hannover, and Nürnberg, especially from Dietmar Harhoff. We are particularly indebted to an anonymous referee for valuable suggestions. Financial support of the DFG is gratefully acknowledged.     

Flood Damage Reduction

Abstract

A fundamental conflict occurs when a floodplain, fluvio-morphologically formed by the river for draining its high flows, is occupied and developed by humanity. Consequently, damages are experienced that are the inevitable costs of occupancy of the floodplain. A systematic methodology is suggested for formulating an optimal scheme for addressing any flood situation with its own unique characteristics. This methodology embraces all available measures, structural and non-structural, traditional and modern, in evolving the best scheme. Diverse flood situations in New Brunswick (Canada), the Nile River Basin and Bangladesh exemplify three flooding situations radically different in origin and character. Finally, some important conclusions are drawn and recommendations are made for approaching solutions to major flood problems     

Flood Management and Sustainable Development of Water Resources: The Case of Great Lakes Basin

Abstract

One challenging issue in flood planning and management is to design and apply integrated approaches to estimate likely future economic, social, and other human vulnerabilities to (and impacts of flood), and to identify desirable options that could be used to reduce these vulnerabilities. Given the uncertainties in flood management, it is difficult to decide which options are effective and desirable. Research on developing well-designed flood management strategies can provide the information and understanding necessary for identifying more effective options and better plans for ensuring regional sustainability. This paper focuses on methodology development for the multi-criteria evaluation of flood management options using the Great Lakes Basin as an example. It starts wivh an introduction of some major concerns about flood management in a context of watershed sustainability. This is followed by an indication of the importance of flood management option evaluation to sustainable water resource development. Then, it presents an integrated assessment (IA) approach to evaluate the performance of alternative flood management options, and to identify more effective and desirable policies. Application of the IA in the case study shows how the approach can be used for identifying the more desirable and effective options     

一图式可视化汛旱工情信息发布系统的应用研究

在基于WebGIS平台上,将一图式可视化图层化应用理念应用于系统设计研发全过程,实现了在webGIS地图上图层组合和叠加业务应用,使汛旱工情信息发布系统能够一图多应用,用户同页自由选择,变化出不同的专题,使信息查询、要素对比、演示更加清晰明了简单方便,以适用于不同的防汛抗旱应用场合。     

变异DDOS攻击方式的攻击防范探析

本文首先介绍了网络攻击对目前网络安全的影响及分布式拒绝服务攻击的工作原理和现状,接着分析了分布式拒绝服务的攻击类型,并探析新型攻击类型的核心技术和防范对策。将新型的DDOS的3类攻击方式：基于堵流量的攻击方式、基于网站脚本的攻击方式、另类攻击方式进行了探析,最后给出攻击方式相应的安全策略和防御对策。     

浅谈城市防洪与水土保持的关系

针对城市防洪与水土保持的关系作了阐述.对城市水土保持进行了分析,阐述了城市防洪和水土保持的特点.最后从硬、软两方面给出了自己的一些粗浅的想法.     

继续加强河北省水文情报预报工作的必要性——对“96·8”暴雨洪水的思考

对“96·8”暴雨洪水进行了简述,就“96·8”期间水文情报预报工作进行了回顾。分析了河北省当前水文情报预报工作现状,浅析了继续加强河北省水文情报预报工作的必要性。     

Multiple unit auctions with strategic price-quantity decisions

Summary. I study a multiple unit auction where symmetric risk-neutral bidders choose prices and quantities endogenously. In the model, bidders (a) may place non-linear valuations on the auctioned units, and (b) bid for several units at the same price (“lumpy” bids). I characterize quantity-symmetric and strictly monotone-increasing price equilibria for discriminatory and competitive auctions, and show that (i) if quantity strategy profiles are equal across auctions revenue- equivalence holds, (ii) expected revenue is higher if bidders bid for the entire supply rather than for shares of it, and (iii) equilibrium allocations may fail to be Pareto-optimal. Received: April 14, 1995; revised version: September 3, 1997     

Implementation and Comparison of Reservoir Operation Strategies for the Hoa Binh Reservoir, Vietnam using the Mike 11 Model

Hoa Binh is the largest reservoir in Vietnam. It has been operated since 1990 with the main purposes of flood control in the Red River basin and hydropower generation. Because these different purposes always cause conflicts and disputes during the flood season, it is desirable to improve the current operational regulations of the reservoir. In this paper, the operation rules of the reservoir are analysed by applying the Mike 11 river modelling tool. The model set up includes the main rivers and tributaries of the Red River basin and a logical decision tree defining the reservoir regulation. These strategies define the reservoir release as function of the time of the year, the actual reservoir stage, and the water level forecast at Hanoi. A data set consisting of twenty years of flood season data was used to evaluate the control strategies with respect to flood control and hydropower generation. The reservoir operation using the complete control system and the current as well as alternative regulation strategies has been evaluated and compared to the actual operation practice. Results showed that the implemented control system performs better than the actual operation. In addition, lowering the target downstream water level for flood control improves the operation with respect to both flood protection and hydropower generation. An alternative strategy where the target water level in the reservoir is increased can improve hydropower generation but at the expense of a reduced flood protection.