贝叶斯模型平均法在流域组合预报中的应用

基于贝叶斯模型法的计算框架,应用概率论和统计学的方法针对多个单一子流域水文模型进行分析处理,得到了较为精确的预报结果。该方法与以往单一预报模拟方法相比,具有综合、完整的优点,基于贝叶斯模型平均法的水文模型组合预报可以给出精度较高的预报模拟结果。     

面向双保证率的水库供水能力优化计算方法研究

随着城市化进程的推进和生态文明理念的深入,水库供水任务日趋复杂,涵盖城镇供水、农业灌溉、生态保障多类目标,分析水库多目标供水能力对于工程的功能调整等决策十分必要。本文综合考虑水库供水目标的竞争性与保证率差异性,提出面向双保证率的水库供水能力双层优化计算方法,通过调度线控制和城镇供水能力区间迭代实现满足不同保证率的多目标供水能力计算。外层基于粒子群算法以城镇供水能力最大为目标对水库调度线进行优化,协调不同用户的供水关系;内层在给定规则下通过迭代计算满足双保证率要求的城镇供水能力。通过内外层嵌套计算实现对水库调度规则和供水能力的同步优化。以三亚市赤田水库为实例进行研究,在城镇供水保证率为95%、农业灌溉保证率为90%时,通过优化调度规则得出水库总供水能力为9400万m~3。设置不同农业保证率和农业需水情景作分析对比,二者均对城镇供水能力有影响,总供水能力随农业保证率降低而提高。分析表明,双层优化计算方法可以实现对调度线的优化,得出满足城镇、农业双保证率要求的供水能力,且计算方法收敛稳定性较高,优化生成的调度线年内分布合理,可为水库多目标供水能力的计算和相关决策提供参考。     

Development and application of a simulation model for reservoir management

The success of irrigation system operation and planning depends on accurate quantification of supply and demand, and an equitable distribution of available water. The ultimate aim of this study was to determine how to meet the irrigation water demands if possible or to minimize the gap between the water supply and the demand. Most of the irrigation literature focuses only on the demand and the distribution aspects of this issue Irrigation projects that receive water from reservoirs, however, can be challenging to manage because the annual fluctuations in available water release from a reservoir can have a considerable impact on the irrigation management strategy. In real‐world situations, the reservoir operating rules guide reservoir operators in making actual water release decisions. This study develops a water balance simulation model for reservoir management, as well as testing it for Kangsabati Reservoir, West Bengal, India. Two rule curves for deciding irrigation water available from the reservoir were generated by taking the average and minimum stage values on a daily basis for a 16‐year period (1988–2003). Maintaining a minimum stage of 120.4 m throughout the year served as another rule to decide the release water available for irrigation. The minimum allowable stage of reservoir corresponding to a particular date of the year can be determined from those reservoir specific rule curves generated for irrigation purposes. The maximum permissible water release/outflow for irrigation from the test reservoir was taken as the volume of water available above the minimum allowable stage corresponding to the selected rule curve. The saturated hydraulic conductivity value (K_S) was calibrated to be 4.31 mm day^?1 for Kangsabati Reservoir.     

施工导流联合泄流计算模型及其软件开发

应用施工水力学方法建立了施工导流的联合泄流计算模型,在此基础上开发了施工导流联合泄流计算软件(CDHCS)。该软件系统由数据库子系统、模型库子系统、图形库子系统、方法库子系统以及帮助系统和人机界面组成。软件既可计算某单一泄水建筑物的泄流能力,又能分析不同型式、高程的多个泄水建筑物的联合泄流能力,研究决策不同的导流方案,为施工导流设计和方案优化提供参考依据。工程实例分析表明,本软件计算结果正确,计算模型合理可行。     

中国货币政策的福利损失与政策规则选择——基于新凯恩斯DSGE模型的分析

本文在新凯恩斯主义DSGE模型框架下,运用福利损失函数和脉冲响应方法研究我国最优货币政策规则选择的问题。研究结果表明,货币供应量规则相对于利率规则,使外生冲击对产出和通货膨胀的影响更持久,造成更大的福利损失,因此中央银行的货币政策规则应该逐步从货币供应量规则转向利率规则;在一定条件下,前瞻型利率规则、后顾型利率规则和泰勒规则所造成的福利损失相差不大,从便利的角度出发,中央银行应该选择后顾型利率规则。     

分布式水资源配置模型DTVGM-WEAR的开发及应用

构建了一个系统描述自然及人类活动作用下水循环路径的分布式水资源系统配置模型。通过将水文及其伴随过程与水资源配置过程进行"在线"或"离线"形式的耦合,基于抽象概化规则框架的规则集合进行水资源配置模拟,形成较为通用的水文-水质-水生态-水资源系统配置模型。该模型能够较好地反映不同配置规则下的水资源分配过程,实现水量、水质、水生态要求的水资源综合配置。实例证明,模型能够根据区域供用水结构特征及用水需求灵活地调整配置规则,为水资源系统合理配置提供较为可靠的模拟结果。     

多属性群决策在项目风险评价中的应用

工程项目的风险因素多,项目风险评价工作比较复杂.基于有序加权平均算子(0WA算子)和加权算术平均算子(CWAA算子)的多属性群决策,整合两种加权算子在纵向和横向集结的优点,对工程项目的风险值进行纵向与横向集结,可以比较有效地消除决策者主观因素的影响,并增加中间值的作用,使工程项目风险综合评价更加科学、合理.实例分析验证了该方法的可行性与有效性.     

壤土夹层对苯和Br-在均质细砂中运移影响的试验分析

为研究粉质壤土夹层对苯和溴离子(Br^-)在非饱和带中入渗的影响,采用成都市金牛区某施工基坑粉质壤土和河砂,验证不同土样对Br^-和苯的吸附性,构建不同构型的土柱进行试验,并分析其运移规律。结果表明:Br^-的吸附程度不会因土样中黏粒含量的增加而增加;土样对苯以线性吸附为主,黏粒含量越高吸附量越大,污染物的运移性越弱;示踪剂Br^-的浓度对土样吸附苯的影响可忽略不计;均质砂土湿润锋推进呈现一定的非线性,夹层以上两种构型土柱进程近乎一致,进入分层后湿润锋推进速度明显减弱,说明夹层具有一定的减渗作用;夹层的存在减弱了Br^-以及苯向下运移,并且粉质壤土对苯有一定的吸附净化作用。研究结果可供从事地下水有机污染研究的人员参考。     

基于动态贝叶斯网络的邻近下穿隧道深基坑施工风险分析

为了减小邻近既有下穿隧道深基坑施工风险及灾害损失,科学预防施工安全事故,提出了一种基于动态贝叶斯网络（DBN）的深基坑施工风险分析模型。首先,运用BWM（best worst method）确定准则的权重;其次,基于关联规则挖掘风险因素间的相互关系,并以此构建DBN结构模型;最后,以新建厦门北站地下一层社会连廊深基坑工程为例,对提出的方法进行有效性和适用性检验。结果表明：基坑围护结构的安全度在静态被评为“较高”和“极高”的概率分别为34.6%和36.1%,且此结果随着输入风险证据发生动态变化,运用反向推理也能迅速找出围护桩渗水风险;提出的模型能明确邻近既有下穿隧道深基坑施工风险传递过程中的关键风险点,并能进行动态风险预测以及事故后致因诊断,从而实现邻近既有下穿隧道深基坑施工风险的动态管控。所提出的优化DBN模型对工前风险评估、先验分析和风险诊断有较好的适用性和较高的准确性,可为邻近既有隧道深基坑施工过程中的安全管控提供有效的决策支持,大幅提高风险控制效率。     

Pattern mining in tourist attraction visits through association rule learning on Bluetooth tracking data: A case study of Ghent,Belgium

The rapid evolution of information and positioning technologies, and their increasing adoption in tourism management practices allows for new and challenging research avenues. This paper presents an empirical case study on the mining of association rules in tourist attraction visits, registered for 15 days by the Bluetooth tracking methodology. This way, this paper aims to be a methodological contribution to the field of spatiotemporal tourism behavior research by demonstrating the potential of ad-hoc sensing networks in the non-participatory measurement of small-scale movements. An extensive filtering procedure is followed by an exploratory analysis, analyzing the discovered associations for different visitor segments and additionally visualizing them in ‘visit pattern maps’. Despite the limited duration of the tracking period, we were able to discover interesting associations and further identified a tendency of visitors to rarely combine visits in the center with visits outside of the city center. We conclude by discussing both the potential of the employed methodology as well as its further issues.