Pan Evaporation Modeling Using Neural Computing Approach for Different Climatic Zones

The purpose of this study was to develop and apply the neural networks models to estimate daily pan evaporation (PE) for different climatic zones such as temperate and arid climatic zones, Republic of Korea and Iran. Three kinds of the neural networks models, namely multilayer perceptron-neural networks model (MLP-NNM), generalized regression neural networks model (GRNNM), and support vector machine-neural networks model (SVM-NNM), were used to estimate daily PE. The available climatic variables, consisted of mean air temperature (T_mean), mean wind speed (U_mean), sunshine duration (SD), mean relative humidity (RH_mean), and extraterrestrial radiation (R_a) were used to estimate daily PE using the various input combinations of climate variables. The measurements for the period of January 1985?CDecember 1990 (Republic of Korea) and January 2002?CDecember 2008 (Iran) were used for training and testing the employed neural networks models. The results obtained by SVM-NNM indicated that it performs better than MLP-NNM and GRNNM for estimating daily PE. A comparison was also made among the employed models, which demonstrated the superiority of MLP-NNM, GRNNM, and SVM-NNM over Linacre model and multiple linear regression model (MLRM).     

基于竖直钻孔数据的层状地层建模

为了解决由竖直钻孔数据构建三维地质模型的问题,提出了基于垂直方向的层状地层的划分方法,由此得到不同属性地层的空间拓扑关系,这些关系决定了地层上下排列序号.通过对每个竖直钻孔上补充排列辅助的数据,最后由序号进行各层相互的切割并产生了完整且较为复杂的三维空间拓扑结构.地层模型采用了基于三棱柱体体元的建模方法.结果证明该方法能较好地解决基于层状的地质结构建模.     

动水水面蒸发实验研究初探

黄河是一条多泥沙河流。以往在计算黄河河道和水库水面蒸发时，都是根据陆地蒸发器观测的清水静水水面蒸发一计算的。这样计算是否会产生较大的误差，一直是大家关心的问题。目前有关动水水面蒸发的研究还很少。我们于１９９５年７－１０月在巴彦高勒蒸发实验站进行了清水，浑水动水蒸发实验。     

Rainfall Extremes: a Novel Modeling Approach for Regionalization

The rainfall events of extreme magnitude over the past few decades have caused destructive damages to lives and properties, especially in the subcontinent (e.g. Pakistan, India, Bangladesh etc). Rainfall hazard maps for these areas can be of great practical and theoretical interests. In our work, we used extreme value analysis and spatial interpolation techniques to provide such maps through a combination of the Tropical Rainfall Measuring Mission Precipitation (TRMM) 3B42 product and raingauge data. This mixed approach takes advantage of both the long time series available at a limited number of stations, and the large spatial coverage of the satellite data which, instead, has a poor temporal extent. The methodology is implemented by (1) creating a unique growth curve for the homogeneous region by utilizing in-situ rainfall data and (2) mapping the parameters of intensity-duration functions for the entire length of the study area by using TRMM 3B42 product. The regional results obtained by using mixed approach and TRMM 3B42 are compared with the estimates obtained by using in-situ data. The comparison showed that the overall output of mixed approach is more consistent with what transpired by in-situ data for a pre-defined return period.     

基于盲数理论的城市污水资源化利用潜力预测模型与方法研究

根据城市污水资源化再生利用系统各单元的水量平衡关系,建立了污水资源化再生利用潜力确定性预测模型,然后针对确定性模型中参数的不确定性,采用盲数理论,尝试性地建立了城市污水资源化再生利用潜力不确定性预测模型。经郑州市郑东新区龙子湖地区实证分析,取得了实用性成果与结论。     

A Novel Approach for Predicting Water Demand with Complex Patterns Based on Ensemble Learning

Predicting urban water demand is important in rationalizing water allocation and building smart cities. Influenced by multifarious factors, water demand is with high-frequency noise and complex patterns. It is difficult for a single learner to predict the nonlinear water demand time series. Therefore, ensemble learning is introduced in this work to predict water demand. A model (Word-embedded Temporal Feature Network, WE-TFN) for predicting water demand influenced by complex factors is proposed as a base learner. Besides, the seasonal time series model and the Principal Component Analysis and Temporal Convolutional Network (PCA-TCN) are combined with WE-TFN for ensemble learning. Based on the water demand data set provided by the Shenzhen Open Data Innovation Contest (SODIC), WE-TFN is compared with some typical models. The experimental results show that WE-TFN performs well in fitting local extreme values and predicting volatility. The ensemble learning method declines by approximately 68.73% on average on the Root Mean Square Error (RMSE) compared with a single base learner. Overall, WE-TFN and the ensemble learning method outperform baselines and perform well in water demand prediction.

     

基于HACCP体系和FTA法的污水处理系统总氮去除可靠性分析方法研究

城市污水处理厂的可靠运行是城市水污染物控制的重要内容。针对A2O污水处理工艺,以总氮（TN）去除为目标,按照危害分析和关键控制点（HACCP）基本原理,结合故障树分析技术（FTA）识别出TN控制的潜在危害,并提出了进水水质特征、生化池、二沉池、污泥回流系统等4类关键控制点和相应的关键限值,为A2O工艺运行过程的可靠性管理提供方法支持。     

科尔沁沙地甸子地土壤蒸发的野外试验研究

采用单因子相关分析、多元回归模拟和灰色关联分析方法研究了科尔沁沙地甸子地不同深度的土壤蒸发量与土壤温度、气温、湿度、风速、日照时数、地下水位埋深等因素的关系.结果表明:用线性方程或指数回归方程拟合土壤蒸发与其影响因素的相关关系,优于二次回归多项式或三次回归多项式.影响土壤蒸发的主要因子是土壤温度和大气温(湿)度,其次是风速和地下水位埋深,而日照时数对土壤蒸发的影响较小.     

基于主成分分析的尉犁灌区水面蒸发量研究

考虑到水面蒸发气象影响因子之间普遍存在显著相关,若应用所有气象因子建立水面蒸发量计算模型则存在信息重叠问题,而主成分分析方法可以解决该问题。尉犁灌区水面蒸发气象影响因子的主成分分析表明,前2个主成分累计贡献率已达97．069％,故提取2个主成分已能满足要求。第一主成分代表空气冷热状况与太阳照射状况;第二主成分代表空气动力状况。利用2个主成分建立二元一次回归方程,并与应用所有气象影响因子建立的多元线性回归方程相比较．结果显示,主成分分析方法建立的回归方程的回归系数均通过t检验,达到极显著水平,多元线性回归方程,虽拟合效果稍优于主成分分析方法,但回归系数b0-b6均未通过t检验,系数显著性水平不如主成分分析法。     

基于滑差同调等值的空调群负荷建模

随着空调负荷比例的迅速增长，对系统的暂态电压稳定逐渐带来威胁。为更好地描述含空调启动的空调群负荷特性，文中将同调等值法扩展到空调群的负荷建模中，提出了基于滑差同调等值的负荷建模方法和模型，用阻尼最小二乘法对含空调启动特性的空调群综合负荷进行建模，通过仿真验证了建模方法的有效性。     

A Fuzzy-Stochastic Modeling Approach for Multiple Criteria Decision Analysis of Coupled Groundwater-Agricultural Systems

The complexity of water resources management increases when decisions about environmental and social issues are considered in addition to economic efficiency. Such complexities are further compounded by multiple uncertainties about the consequences of potential management decisions. In this paper, a new fuzzy-stochastic multiple criteria decision-making approach is proposed for water resources management in which a variety of criteria in terms of economic, environmental and social dimensions are identified and taken into account. The goal is to evaluate multiple conflicting criteria under uncertainties and to rank a set of management alternatives. The methodology uses a simulation-optimization water management model of a strongly interacting groundwater-agriculture system to enumerate criteria based on these bio-physical process interactions. Fuzzy and/or qualitative information regarding the decision-making process for which quantitative data is not available are evaluated in linguistic terms. Afterwards, Monte Carlo simulation is applied to combine these information and to generate a probabilistic decision matrix of management alternatives versus criteria in an uncertain environment. Based on this outcome, total performance values of the management alternatives are calculated using ordered weighted averaging. The proposed approach is applied to a real world example, where excessive groundwater withdrawal from the coastal aquifer for irrigated agriculture has resulted in saltwater intrusion, threatening the economical basis of farmers and associated societal impacts. The analysis has provided potential decision alternatives which can serve as a platform for negotiation and further exploration. Furthermore, sensitivity of different inputs to resulting rankings is investigated. It is found that decision makers’ risk aversion and risk taking attitude may yield different rankings. The presented approach suits to systematically quantify both probabilistic and fuzzy uncertainties associated with complex hydrosystems management.     

A New Approach to Incorporating Environmental Flow Requirements in Water Allocation Modeling

The condition of river, wetland and estuarine ecosystems is largely determined by the prevailing flow regime. The flow regime can be described by the magnitude, frequency, timing, duration and rate of change of both intra-annual and inter-annual events. The required flow regime, necessary to maintain the ecosystem in a particular condition, is referred to as the environmental flow requirement. To appropriately take environmental flow requirements into consideration in water resources planning and management, it is required that models used in water resources planning can accommodate the specific characteristics of the environmental flow requirements. This paper presents a new functionality in the generic water resources planning package ‘RIBASIM’, which allows for realistic allocation of particularly the high flow pulses and small and large floods that are part of an environmental flow requirement. Tests of this functionality with a model application based on the characteristics of the Mahabad basin in Iran show that the use of this functionality can help to find environmental flow release options that lead to smaller losses for other water users, which would not have been found easily if the traditional approach was used.     

河工模型试验模拟技术探讨

在河工变态模型试验中,几何变态造成水流的流速场和动力场不完全相似,具体反映在糙宰相似、起动切应力与起动流速不协调及时间变态等问题上。从动力调整的新视角来分析,在变态模型试验中,可将模型旋转改变比降,调整糙率,解决阻力相似和起动流速与起动切应力的不协调问题;动床模型时间变态会使模型中最基本的水力因素的相似性产生严重偏离,目前使用的任何校正措施都难以奏效。分析发现使用动力调整技术,可以改变模型水流的挟沙能力,进而影响冲淤变形时间比尺。提出了解决时间变态问题的一个新途径。     

基于时间同步技术的新型远方终端单元设计

传统远方终端单元（RTU）的非同步测量和数据传输延时是电力系统数据采集与监视控制（SCADA）系统数据误差的主要来源。提出了一种基于全球定位系统（GPS）和以太网时间同步技术的同步化RTU，以更低的成本实现类似于相量测量单元（PMU）的同步测量和数据快速回传。硬件主要由数据调理和采样电路、本地人机接口（MMI）、同步采样控制电路和以太网通信电路等部分构成。通过时钟同步、同步采样和同步时标处理等环节，同步测量单元（SMU）能够给上位机数据库提供高精度带时标的数据。设计兼顾了同步测量能力和成本，以便在系统中广泛配置。     

基于ANSYS的石膏山拱坝三维弹塑性分析

利用大型商用软件ANSYS对石膏山水库单曲拱坝进行了三维弹塑性分析,阐述包括工程地形、坝体温度的整个拱坝的建模方法过程,根据弹塑性分析成果复核了原设计中的多拱梁分载法,对工程设计和施工提供了重要参考和指导。     

基于三维地质解析的拱坝拱座抗滑稳定分析

在充分考虑滑裂面阻滑力影响的基础上,建立拱坝拱座滑体区域三维地质模型,进行三维极限平衡分析。在不同高水位工况下,分析地质结构面发育特征及其与坝体空间位置关系,获取危险滑块组合,得出块体要素及地质条件等相关数据,保证抗滑稳定计算边界条件的精准度。同时,将平面地质解析结果三维数字化,可直观表达危险滑块的稳定性与地质构造的关联性,便于拱座稳定与地质条件的综合分析。淋溪河水电站拱坝实际工程应用表明,该方法对拱座的抗滑稳定分析结果合理有效。     

山西省水面蒸发初步分析

水面蒸发是反映当地蒸发能力的指标,分析其时空分布和特性。对区域水资源评价与规划十分重要。本文通过对山西省1980年-2000年水面蒸发资料的全面剖析,阐述了山西省水面蒸发量的特点。     

A Socioeconomic Valuation of an Irrigation System Project Based on Real Option Analysis Approach

Traditional net present value methods used to evaluate potential projects make no allowance for flexibility and assume a static environment. The concept of real options has extended into irrigation systems to model design flexibility in the realistically uncertain environment. In particular, this article extends the evaluation techniques of an irrigation dam by combining the real options approach along with the traditional on (Discount Cash Flow). However, whereas financial options are well-defined traded contracts, real options in irrigation systems are a priori undefined, complex and interdependent. Moreover, irrigation systems involve many more options than designers could consider. Therefore designers need to identify the real options most likely to offer good flexibility and the most value. This paper demonstrates the ease that irrigation systems economic analysis with risk analysis and real options can be valued by simulation software that is readily available to owners of personal computers. Sequentially, Discount Cash Flow analysis accompanied with real options approach facilitates decision making and encourages more sophisticated and realistic economic analysis of irrigation systems.     

一种谐波负荷建模的新方法

精确的负荷谐波建模对于网络谐波分析具有重要意义。文中叙述了负荷谐波建模的研究现状，针对理论上通用的负荷谐波模型，根据函数最佳平方逼近的思想，提出了一种新的参数辨识方法，即利用模型中电压、电流之间的物理关系，通过对电流的最佳平方逼近辨识出相应参数。该算法简单易行，可对各种类型的负荷进行谐波建模。为检验算法的精确度，定义了误差分析函数。该算法与以往算法相比，具有更高的精度，验证了算法的有效性和可行性。最后，讨论了电压、电流的幅值和相角对辨识所得参数的影响。     

基于细观力学的脆性岩石通用损伤模型

岩石是在形成和运移过程中经过各种改造的地质产物,因而具有复杂的非线性特征。这种特征在微观上主要表现为岩石结构的非连续性和不确定性,很难用传统的、基于线性分析基础之上的方法来描述。基于细观力学分析和通过尺度变化（宏观－细观－宏观）来考虑岩石材料体积表征单元内单个裂纹的贡献,提出了一个脆性岩石通用损伤模型。该模型根据对损伤变量或内变量的不同定义（如：宏观量和微观量）,可以表现为唯象模型和细观力学模型;通过对损伤变量或内变量的阶数的不同定义（如：标量、矢量和张量）,此模型亦可以表达为各向同性或各向异性损伤模型。