Optimization and capacity expansion of a water distribution system     

Nien-Sheng Hsu  Wei-Chen Cheng  Wen-Ming Cheng  Chih-Chiang Wei  William W.-G. Yeh 《Advances in water resources》2008

This paper develops an iterative procedure for capacity expansion studies for water distribution systems. We propose a methodology to analyze an existing water distribution system and identify the potential bottlenecks in the system. Based on the results, capacity expansion alternatives are proposed and evaluated for improving the efficiency of water supply. The methodology includes a network flow based optimization model, four evaluation indices, and a series of evaluation steps. We first use a directed graph to configure the water distribution system into a network. The network flow based model optimizes the water distribution in the system so that different expansion alternatives can be evaluated on a comparable basis. This model lends itself to linear programming (LP) and can be easily solved by a standard LP code. The results from the evaluation tool help to identify the bottlenecks in the water distribution system and provide capacity expansion alternatives. A useful complementary tool for decision making is composed of a series of evaluation steps with the bottleneck findings, capacity expansion alternatives, and the evaluation of results. We apply the proposed methodology to the Tou-Qian River Basin, located in the northern region of Taiwan, to demonstrate its applicability in optimization and capacity expansion studies.  相似文献   

大连市气象局网络安全系统的设计与实现   总被引：2，自引：1，他引：1  

徐晓波  王会品  张建国 《气象与环境学报》2007,23(6):35-38

根据安全网络的要求,利用先进的网络安全技术与设备,针对大连市气象局局域网在网络结构、网络安全方面存在的问题及隐患,提出网络系统改造方案及加强网络安全的措施:网络改造方案中采用子网划分技术重新规划网络结构,实现子网划分;针对可能存在的内、外部网络攻击,部署了多层次防线,对边界防毒和应用服务器防毒及客户端防毒均作了相应的部署。采用虚拟专用网络(virtual private network,VPN)技术、虚拟局域网(virtual local area network,VLAN)技术、网络版病毒防护软件、网关防毒产品、防火墙技术和物理隔离等多种专业网络安全产品,构建整体安全网络系统。实施后表明:网络安全得到保障,网络通信质量显著提高,达到了建设安全、畅通、高速局域网络的目的。  相似文献   

Earthquake detection probability within a seismically quiet area: application to the Bruchsal geothermal field          下载免费PDF全文

Emmanuel Gaucher 《Geophysical Prospecting》2016,64(2):268-286

In applications such as oil and gas production, deep geothermal energy production, underground storage, and mining, it is common practice to implement local seismic networks to monitor and to mitigate induced seismicity. For this purpose, it is crucial to determine the capability of the network to detect a seismic event of predefined magnitude in the target area. The determination of the magnitude of completeness of a network is particularly required to properly interpret seismic monitoring results. We propose a method to compute the detection probability for existing local seismic networks, which (i) strictly follows the applied detection sequence; (ii) estimates the detection capability where seismicity has not yet occurred; and (iii) delivers the results in terms of probabilities. The procedure includes a calibration of a local magnitude scale using regional earthquakes recorded by the network and located outside the monitored area. It involves pre‐processing of the seismograms recorded at each station as performed during the triggering sequence, which is assumed based on amplitude thresholds. Then, the calibrated magnitude–distance–amplitude relations are extrapolated at short distances and combined to reproduce the network detection sequence. This generates a probability to detect a seismic event of a given magnitude at a specified location. This observation‐based approach is an alternative to a fully theoretical detection capability modelling and includes field conditions. Seismic wave attenuation by geometrical spreading and intrinsic attenuation, site effect, and instrumental responses are partly accounted for by the calibration. We apply this procedure on the seismic network deployed in the Bruchsal geothermal field (Germany). Although the system was in good working order, no induced seismicity was identified in the area between June 2010, when monitoring started, and November 2012. The recording of distant seismicity during this time period, however, allowed the application of the proposed procedure. According to the applied network detection parameters, the results indicate that the absence of seismicity can be interpreted as a 95% probability that no seismic event with M_L ≥ 0.7 occurred below the network at 2.4‐km depth, i.e., in the geothermal reservoir.  相似文献   

福建测震台网单台震级偏差与台站场地响应关系的初步分析     

杨贵  许振栋  林彬华 《中国地震》2016,32(4):674-684

利用福建测震台网2008年10月~2015年12月记录的每个事件至少有6个台站测算震级的3069个区域地震事件,进行单台震级与台网平均震级的偏差统计,获得了各台站的总的震级平均偏差为-0.31~0.68,并统计各台站测算震级所量取最大记录振幅相应的周期,获得优势周期为0.06~0.38s;通过Moya方法反演各测震台站的场地响应,获得98个台站对1~20Hz频带的场地响应,结果显示场地对某些频带信息有放大或抑制作用;通过比较Wood-Anderson地震仪摆固有0.8s周期所对应的场地响应、各台样本优势周期所对应场地响应的震级偏差与各台总的震级平均偏差,发现台站测算震级相应优势周期的场地响应的震级偏差与台站震级平均偏差有较好的线性关系,表明单台震级的偏差与测算震级所量取最大记录振幅相应的周期的场地响应有较大关系。  相似文献   

中国高铁网络结构特征及其组织模式   总被引：2，自引：4，他引：2  

钟业喜  郭卫东 《地理科学》2020,40(1):79-88

基于2018年高铁网络OD数据,运用社会网络分析方法从高铁网络、城市节点等方面探讨中国城市高铁网络结构特征及其地域组织模式,结果表明：①中国高铁网络整体较为松散,东北地区网络密度最高,东部和中部地区作为整体网络的中介作用明显;②重要高铁线路的“廊道效应”突出,中心度呈现出以京广、京沪和沪昆高铁组成的“三角旗状”空间格局并向两侧城市呈不规则递减的态势;③多层级网络识别出紧密关联高铁线路和四横四纵向八横八纵格局的转变;④高铁网络的地域组织形式表现为点-轴串珠模式、双核组团模式和极核模式,高铁网络的完善使组织模式由单核趋向于网络化转变。  相似文献   

地理信息系统中的网络模型   总被引：2，自引：2，他引：0  

狄小春 《地理研究》1990,9(1):35-40

社会中的很多空间现象,如交通、信息交流和生活消费品的运输等都是线性的。在ARC INFO地理信息系统(GIS)中,这些线性现象经过组织和处理,能够建立成网络及其数据库。从而可用来解决资源的合理分配和流动、交通运输中的最佳路线选择等问题。  相似文献   

System identification for nonlinear maneuvering of large tankers using artificial neural network     

G. Rajesh  S.K. Bhattacharyya   《Applied Ocean Research》2008,30(4):256-263

This paper deals with the application of nonparametric system identification to a nonlinear maneuvering model for large tankers using artificial neural network method. The three coupled maneuvering equations in this model for large tankers contain linear and nonlinear terms and instead of attempting to determine the parameters (i.e. hydrodynamic derivatives) associated with nonlinear terms, all nonlinear terms are clubbed together to form one unknown time function per equation which are sought to be represented by the neural network coefficients. The time series used in training the network are obtained from simulated data of zigzag maneuvers and the proposed method has been applied to these data. The neural network scheme adopted in this work has one middle or hidden layer of neurons and it employs the Levenberg–Marquardt algorithm. Using the best choices for the number of hidden layer neurons, length of training data, convergence tolerance etc., the performance of the proposed neural network model has been investigated and conclusions drawn.  相似文献   

Soft computing approach for real-time estimation of missing wave heights     

S.N. Londhe   《Ocean Engineering》2008,35(11-12):1080-1089

This paper presents soft computing approach for estimation of missing wave heights at a particular location on a real-time basis using wave heights at other locations. Six such buoy networks are developed in Eastern Gulf of Mexico using soft computing techniques of Artificial Neural Networks (ANN) and Genetic Programming (GP). Wave heights at five stations are used to estimate wave height at the sixth station. Though ANN is now an established tool in time series analysis, use of GP in the field of time series forecasting/analysis particularly in the area of Ocean Engineering is relatively new and needs to be explored further. Both ANN and GP approach perform well in terms of accuracy of estimation as evident from values of various statistical parameters employed. The GP models work better in case of extreme events. Results of both approaches are also compared with the performance of large-scale continuous wave modeling/forecasting system WAVEWATCH III. The models are also applied on real time basis for 3 months in the year 2007. A software is developed using evolved GP codes (C++) as back end with Visual Basic as the Front End tool for real-time application of wave estimation model.  相似文献   

GPS与数字水准仪相结合进行三维控制网的布设   总被引：2，自引：1，他引：1  

李井春  夏立福 《海洋测绘》2008,28(3):59-62

通过三维控制网的实际布设，对GPS平面控制网的精度和数字水准仪布设的高程控制网的精度进行了分析探讨，并对二者如何更加有效的结合提出了几点有益的见解。  相似文献   

Concentration–discharge relationships reflect chemostatic characteristics of US catchments     

Sarah E. Godsey  James W. Kirchner  David W. Clow 《水文研究》2009,23(13):1844-1864

Concentration–discharge relationships have been widely used as clues to the hydrochemical processes that control runoff chemistry. Here we examine concentration–discharge relationships for solutes produced primarily by mineral weathering in 59 geochemically diverse US catchments. We show that these catchments exhibit nearly chemostatic behaviour; their stream concentrations of weathering products such as Ca, Mg, Na, and Si typically vary by factors of only 3 to 20 while discharge varies by several orders of magnitude. Similar patterns are observed at the inter‐annual time scale. This behaviour implies that solute concentrations in stream water are not determined by simple dilution of a fixed solute flux by a variable flux of water, and that rates of solute production and/or mobilization must be nearly proportional to water fluxes, both on storm and inter‐annual timescales. We compared these catchments' concentration–discharge relationships to the predictions of several simple hydrological and geochemical models. Most of these models can be forced to approximately fit the observed concentration–discharge relationships, but often only by assuming unrealistic or internally inconsistent parameter values. We propose a new model that also fits the data and may be more robust. We suggest possible tests of the new model for future studies. The relative stability of concentration under widely varying discharge may help make aquatic environments habitable. It also implies that fluxes of weathering solutes in streams, and thus fluxes of alkalinity to the oceans, are determined primarily by water fluxes. Thus, hydrology may be a major driver of the ocean‐alkalinity feedback regulating climate change. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献