Influence of the impounding process of the Three Gorges Reservoir up to water level 172.5m on water eutrophication in the Xiangxi Bay

The water level of the Three Gorges Reservoir(TGR) rose to 172.5 m in two stages from September to November,2008.The hydrodynamic parameters and water quality parameters(e.g.flow velocity,temperature,turbidity and nutrient content) had been continuously monitored to reveal the influence of the impounding process of the TGR on the water eutrophication in the Xiangxi Bay(XXB).The maximal daily rise of the water level of the TGR was about 2.38 m.The water exchange between the mainstream(the Changjiang River) a...     

A real-time probabilistic channel flood-forecasting model based on the Bayesian particle filter approach

Reliable real-time probabilistic flood forecasting is critical for effective water management and flood protection all over the world. In this study, we develop a real-time probabilistic channel flood-forecasting model by combining a channel hydraulic model with the Bayesian particle filter approach. The new model is tested in the upstream river reach of Three Gorges Dam (TGD) on the Yangtze River, China. Stage observations at seven hydrological stations are used simultaneously to adjust the Manning's roughness coefficients and to update discharges and stages along the river reach to attain reliable probabilistic flood forecasting. The synthetic experiments are applied to demonstrate the new model's correction and forecasting performances. The real-world experiments show that the new model can make accurate flood forecasting as well as derive reliable intervals for different confidence levels. The new probabilistic flood forecasting model not only outperforms the existing deterministic channel flood-forecasting models in accuracy, but also provides a more robust tool with which to incorporate uncertainty into flood-control efforts.     

Impacts of water release operations on algal blooms in a tributary bay of Three Gorges Reservoir

Water release operation is crucial for water quality in large reservoirs such as Three Gorges Reservoir(TGR),because it determines the hydrodynamics and hence the self-purification capability.As algal blooms were often observed in some tributary bays of TGR during the release periods,high frequency field observations were carried out in a typical eutrophic tributary bay(Xiangxi River) from February 9 to May 10,2009.In this paper we assess the hydrodynamic behaviour,density stratification,and trophic status ...     

重庆智慧洪水灾害防御研究

本文结合重庆市的洪水特点,即过境洪水和山洪相互叠加、受三峡水库回水顶托影响、极易引发次生地质灾害,提出了重庆市智慧洪水灾害防御的总体框架和建设内容,并结合已经完工的重庆防汛管理信息化建设项目（一期）,梳理总结了在智慧洪水灾害防御方面所取得的成果,提出了一套集实时洪水预报、水库防洪调度、河道洪水演进、水库回水模拟、水库溃坝模拟、洪水淹没及洪灾损失计算、防汛形势分析、应急预案智能研判、水库大坝安全评估、三维动态仿真等于一体的流域洪水过程全链条分析功能体系,并以重庆主城区为核心的6个流域43条河流、49个重要区域的洪水进行了实验验证,证明方法可行,效果很好,为重庆市防汛决策管理打造了智能的业务支撑体系,具有较大的推广应用价值。     

尾矿库防洪能力可靠性分析

以磨憨光明采选厂干尾矿渣库为例,对尾矿库防洪能力可靠性进行分析,通过计算尾矿库洪峰流量、洪水总量并进行调洪验算以确定该尾矿库的防洪能力。计算结果表明,该尾矿库满足防洪要求。     

辽宁省小型水库安全度汛信息管理系统研究与实现

为转变辽宁省小型水库报汛模式,提高报汛效率及可靠性,在现有短信报汛工作基础上,综合运用云计算、大数据、移动互联网等技术,采用基于云MAS短信报汛技术,Android和IOS 2种手机App开发框架,"一级部署、三级应用"等研究方法,开发面向省、市、县各级工作及管理用户的统一框架的小型水库安全度汛信息管理系统,主要包括度汛信息管理系统和智能手机报汛巡检App 2个部分,包含水库报汛、巡查监管等10余项功能模块.经过2 a多的汛期运行,该成果在实际防汛工作中发挥重要作用,已经成为全省小型水库报汛不可替代的重要手段.实践检验表明:小型水库安全度汛信息管理系统的研究与实践工作是非常必要的,可实现从短信报汛向智能手机报汛的转变,有效提高全省小型水库报汛水平,为其他类似地区水库报汛工作提供借鉴意义.     

洪水演进模拟的三维可视化研究

洪水资源利用的关键在于了解洪水的发生过程及其运动规律,再现洪水的演进状态。通过对流域三维地形仿真、洪水演进模拟的三维可视化研究,以GIS数据为基础,采用VC++结合OpenGL的可视化开发环境建立了洪水演进模拟系统,实现了以给定洪水水位的方式再现洪水演进的动态模拟,为洪水资源化的研究奠定了基础。     

基于数字地球的洪水淹没分析及仿真研究

针对洪涝灾害中洪水淹没问题,采用现代信息技术对洪水进行淹没分析和三维仿真。基于瓦片金字塔模型生成研究区域的三维地形,在此基础上按照精度要求构建指定步长的矩形格网模型,对给定洪水水位值和洪水量已知的两种情况分别进行洪水淹没分析,提出洪水淹没仿真系统体系,采用三维仿真技术对洪水淹没进行三维仿真进行淹没过程的三维仿真。实例表明,方法具有较好的实用性,对防洪决策及洪灾后评估等具有重要意义。     

Sediment delivery ratio and its uncertainties on flood event scale:Quantification for the Lower Yellow River

Sediment delivery ratio(SDR)for fluvial rivers was formulated with sediment rating curve.The observed data of SDR on flood event scale of the Lower Yellow River(LYR)were adopted to examine the formulation and to calibrate the model parameters.A regression formula of SDR was then established and its 95%prediction interval was accordingly quantified to represent its overall uncertainties.Three types of factors including diversity of the incoming flow conditions,river self-regulation processes,and human activi...     

三峡库区遥感岩性分类规则挖掘

三峡库区属于南方高植被覆盖区域,岩石上部覆盖着较厚的土壤和茂密的植被,因此岩性分析比较困难,尚无成熟的方法可循。针对三峡库区这一地形复杂、地质灾害频繁、土壤植被发育的地区进行遥感岩性分析;采用面向对象（像素集团）的思想,构造光谱、纹理、植被覆盖三类指标集。通过将遥感影像与地质图叠加,采用决策树C5.0算法,挖掘出三峡库区嘉陵江组二段T₁j²,嘉陵江组三段T₁j³,巴东组一段T₂b¹,巴东组二段T₂b²等地层的岩性分类规则,从而为三峡库区岩性的智能分类和解译提供重要的信息和先验知识。     

基于SWMM模型的城市暴雨洪水模拟与分析

为了进行城市暴雨洪水模拟分析,以湖北省恩施市中心城区为研究区域,在河流水系分布和洪水来源分析的基础上,提出洪水分析计算方案,构建一、二维耦合SWMM模型计算典型频率(10,20,50,100年一遇)河道洪水演进和漫堤淹没过程,获得较为准确的洪水淹没范围、水深、淹没历时和洪峰到达时间等信息,并结合GIS进行洪水影响评价。结果表明,清江干流主要河段基本满足20年一遇的防洪标准,清江干流和龙洞河部分河段现状防洪能力较低。SWMM模型是一种成熟的城市雨洪径流模型,适宜于城市暴雨洪水模拟与分析应用。     

基于AAF架构的洪水灾情评估优化系统的设计

针对防汛工作中信息更新频繁、信息量庞大、信息种类繁多的问题,按照J2EE的标准,采用MVC软件开发模式,以AAF为开发框架,建立了一套扩展性强、维护方便和代码重复利用率高的洪水灾情评估优化系统。该系统实现了对灾情进行多角度、实时快速的评估,并且针对结果的差异性,引入AHP法,创建了综合优化模型,对多种评估结果进行了再优化,为抗洪减灾的决策提供了一种更科学有效的方法。通过实例验证,表明该系统稳定可靠,优化结果信息量全面,更具有代表性。     

2020年大洪水科学防御的实践与思考

2020年我国发生了1998年以来最严重的汛情。水利部门深入贯彻"两个坚持、三个转变"理念,聚焦三大突出风险,完善预案体系,提高监测预报预警能力,科学调度水利工程,洪水防御工作取得重大胜利。简要分析2020年我国雨情水情汛情灾情主要特点,介绍超前部署防范、滚动预测预报、水工程调度、山洪灾害预警、暗访督查等洪水防御重点工作,总结智能感知、多源信息融合、互联网、大数据、人工智能、5G等科学技术在长江,淮河,太湖、松花江等流域性洪水防御中的实践运用,针对防洪薄弱环节和短板,立足"十四五"国家水安全保障规划,提出新时代智慧防汛建设的思考。     

HHT在年最大洪峰流量规律分析中的应用

Hilbert-Huang变换能够定量描述非线性、非平稳、弱相依、高度复杂时间序列的时频特性,较传统的时间序列分析方法更具优势。通过对时间序列进行EMD分解,得出其演化过程的内在模函数和趋势项,并对内在模函数做Hilbert-Huang变换,获得序列的变化周期。以汉江上游的两个代表水文站——石泉和安康水文站的年最大洪峰流量为例分析,石泉站年最大洪峰流量变化存在3.06年、7.11年和24.98年的周期,安康站年最大洪峰流量变化存在3.01年、6.07年、15.97年和29.65年的周期,且两站的年最大洪峰流量序列呈降低的趋势。     

Improved hybrid simulated annealing algorithm for navigation scheduling for the two dams of the Three Gorges Project

The purpose of this paper is to deal with the optimal navigation co-scheduling (NCS) for the two dams of the Three Gorges Project in China, i.e., the Three Gorges Dam and the Gezhouba Dam. The co-scheduling includes the operational scheduling for all five locks of the two dams, and the dispatching scheduling to ships applying to pass the dams. Compared with the flexible manufacturing system (FMS), a mixed-integer nonlinear programming model is designed for the NCS, and an improved hybrid algorithm of simulated annealing and local search is addressed to obtain optimal scheduling. Experiments based on real historical execution data show that the approach is feasible.     

小样本跳变水质时序数据预测方法

根据三峡库区某些断面水质监测数据具有样本小、成库前后数据出现跳变的特点,提出一种适用于三峡库区的水质参数预测模型（ELS-SVM）。ELS-SVM通过建立数据预处理模型对原始小样本时序数据进行处理,增强了时序数据的平稳性,并使用模拟退火（SA）算法优选最小二乘支持向量机（LS-SVM）模型参数。与典型的小样本预测模型的比较实验表明,ELS-SVM模型更适用于三峡库区小样本水质时序数据的预测。     

基于SVM分类器的SYN Flood攻击检测规则生成方法的研究

洪泛攻击（SYN flood）是目前最常用的拒绝服务攻击之一,它通过发送大量TCP请求连接报文,造成大量的半连接从而消耗网络资源．由于洪泛攻击中所使用的数据包都是正常数据包,又采用了伪IP技术,使得对其的检测和阻断都十分困难．本文分析了洪泛攻击的攻击原理以及检测并阻断攻击困难的原因,提出了二次检测的防御方法,先用SVM异常检测分类器检测出攻击报文．再依据报文相似度生成误用检测规则从而阻断攻击报文．试验结果表明这种方法对SYN flood攻击的检测效果明显。     

三峡库区岩性植被关联规则挖掘

三峡库区属于南方高植被覆盖区域,岩石上部覆盖着较厚的土壤和茂密的植被,因此岩性分析比较困难,尚无成熟的方法可循。三峡库区遥感岩性分析的关键在于分析表层植被与岩性的关系,寻找消除表层植被的影响直接提取岩性信息的方法。针对三峡库区这一地形复杂、地质灾害频繁、土壤植被发育的地区分析和挖掘出岩性和植被的关联规则;通过将遥感影像与地质图叠加,计算植被指数NDVI图像,在各地层内随机选点,分析各点的岩性与NDVI值的关系,基于概念格算法和规则提取,挖掘出三峡库区嘉陵江组二段T₁j²,嘉陵江组三段T₁j³,巴东组一段T₂b¹,巴东组二段T₂b²,大冶组T₁d等地层的岩性和植被的关联规则。     

Optimizing the evaluation of calculus expressions in a relational database system

There is an interesting search strategy (due to James B. Rothnie) for efficient implementation of a limited kind of selection criterion for a relational database. This strategy is here generalized to arbitrary relational calculus expressions, and an analysis of the resulting improvement of performance is given. The strategy is used in a relational database system TGR and an overview of the architecture of this system is presented. TGR uses microprogrammed database primitives for searching the database. This approach is very similar to the use of a database processor although it also allows flexible change of processor design. The behaviour of TGR in evaluating typical queries is analyzed and the results are used for pointing out the bottlenecks in a relational database system with a particular type of structure. As a conclusion the construction of a database processor with the database primitives from TGR as instruction set is recommended. This would be a step towards getting acceptable performance in a relational database system.     

基于GPRS的三峡库区滑坡监测系统实现

面对三峡工程的完工,三峡库区的水位上升到175M,三峡库区有复杂的地形和很多的滑坡地带,而单纯的采用有线的通信方式是相当的困难的,有的时候是根本无法实现的。本文介绍一种基于GPRS方式作为三峡库区滑坡监测数据采集和传输的方式,从而为三峡库区崩塌、滑坡的防治与预警开辟了一条新思路。