Methodology for Estimating Streamflow by Water Balance and Rating Curve Methods Based on Logistic Regression

Both water balance (WB) and rating curve (RC) are methods for estimating streamflow. The first is mostly used to estimate reservoir outflows, while the second is usually adopted in hydrometeorological network streamflow gauges. While WB uses hourly collected data, the RC estimates streamflow using current water level and extrapolation techniques. The objective of this study was to analyze variations in the reservoir’s hourly outflow at Queimado Hydroelectric Power Plant (HPP Queimado) and to propose a method to evaluate whether the estimate of the daily outflows, obtained by the WB method, is similar to the flow values obtained at a conventional station. The logistic regression (LR) model was used because it is a method that adopts binary, categorically dependent variables to identify the event of interest. The results showed that the values of streamflow, obtained from an average of two daily readings, were a good representation of the flows in the region. The LR was able to identify atypical data, especially in the rainy season. This means that data consistency analysis can be faster and safer, when adequately employed and considering the proposed conditions, contributing to both management policies and the management of water resources.

     

基于 MODIS 影像分析的关中地区干旱监测

以 MODIS 数据为基础资料, 以归一化干旱指数(NDDI) 作为干旱监测指标, 通过预处理、 波段运算、 影像分类 分析和分类后处理等过程, 实现对关中地区的旱情监测。根据监测得到的各区县不同程度的干旱面积, 通过赋权计 算得到各区县的综合干旱程度, 为区域主动应对、 抵御干旱奠定了基础。结果显示, 在监测时间点, 关中地区的 30 个区县中仅有西安、 宝鸡、 凤翔处于轻旱状态; 蓝田等 5 个区县处于中旱状态; 户县等 10个区县处于重旱状态; 阎良 等 12 个区县处于极旱状态。     

基于极限学习机的堤防工程多元风险指标评价方法

为提高堤防工程风险评价的准确性,提出了基于极限学习机的堤防工程多元风险指标评价方法。首先,综合考虑影响堤防风险的28个评价指标,利用层次分析法从预警系统、堤防工程系统、环境系统和社会经济系统这4个方面建立了堤防工程多元风险评价指标体系。接着,基于极限学习机算法对28个指标进行标准化处理及分级标准构建,以风险指标作为输入量,分级隶属度作为输出量,划分风险等级,量化评价指标,估计多元风险评价指标值和判断风险的严重程度。最后,依托鄱阳湖重点堤防——康山大堤,构建多元风险评价指标体系,运用极限学习机算法计算多元风险评价指标值。评价结果表明:康山大堤目前处于基本安全水平,符合康山大堤经过两次加固后的工程实际情况,并与其他方法进行对比,验证了提出方法的可靠性和有效性。该方法可拓展应用到其他重要水工结构工程风险评估中。     

黄土区SCS-CN模型径流曲线数计算方法研究

美国农业部开发的SCS-CN模型是较为常用的一种径流计算方法。模型中的CN值是模型中反映土地利用、土壤类型和土壤前期含水量的一个综合参数,其值的选择对于准确计算地表径流具有重要意义。利用黄土高原地区杨青川流域、燕沟流域和西川流域不同土地利用类型42场模拟降雨的径流资料,应用平均值法、中值法、算术平均值法、S对数频率分布法和渐近线法5种方法计算CN值,并利用CN值反推径流深。采用均值比较、模型评价指标的方法比较了5种方法计算的径流深与实测值的差异,根据相对隶属度最大最优原则确定最优计算方法。结果表明:在杨青川流域,最优的计算方法是平均值法,燕沟流域和西川流域的最优计算方法则是中值法,不同流域同一计算方法确定的同一土地利用类型CN值差异较大;单独进行草地和裸地的评价分析时,草地的最优计算方法是平均值法,裸地的最优计算方法是算术平均值法,不同土地利用类型CN值的最优计算方法不同。     

基于粗糙数BWM_ ELECTRE方法的水库移民安置区优选

移民安置是水库工程建设的重要组成部分,而移民安置区的选址直接关系到移民安置工作的成败。通过引入粗糙数的概念,对不同决策者的主观偏好进行整合,得到以粗糙数形式表示的群体偏好信息,用最优最劣法(BWM)确定指标权重,并采用基于粗糙数的消去与选择转换法(ELECTRE)对备选方案进行排序,构建了基于粗糙数BWM_ELECTRE方法的水库移民安置区优选模型。实例分析验证了该模型的可行性和有效性。     

基于期权博弈理论的发电投资决策

电力工业的市场化改革为发电投资决策带来了更多的不确定因素，也引起了风险。另一方面，其他发电公司的投资策略也会对所研究的发电公司投资收益产生影响。因此，发电公司在制定将来的投资决策时，除了要考虑不确定性因素外，还需要分析其他发电公司的投资行为。基于期权博弈理论，构造了电力市场环境下发电投资决策的一种新的方法框架。在假定发电投资者进行投资决策时所面对的不确定性因素主要来自于负荷增长、同时考虑了其他发电投资者的投资行为的情况下，发展了基于期权博弈理论的发电投资的数学模型和求解方法。最后，用仿真算例说明了所提出的方法的基本特征，并在此基础上，分析了允许的发电公司报价上限对发电投资决策的影响。     

基于表码的电量数据处理方法

从现场采集的电量表码数据直接用于电量结算时，计算出的电量值可能存在很大偏差。根据原始电量数据是等间隔的时序数据的特点，首先通过将缺失数据自动补录和异常数据自动校验修正，以保证数据的连续性和完整性;然后通过对回零、更换电表、更换电流互感器和电压互感器、旁代路等计量业务的自动处理，以简化电量计算方法;最后通过对缺失电量的手工追补和电量数据的比对校验，以减少电量的损失，进一步验证结算电量数据的正确性。该方法在河北购电管理系统中获得了很好的实践效果。     

基于扭矩贯入指标和神经网络的围岩质量预判方法

全断面岩石掘进机(TBM)的地质适应性较差,当遭遇不良地质条件或者围岩质量较差时,容易引发卡机、塌方等地质灾害,影响施工进度,威胁人员安全。基于此,首先通过TBM数据预处理,将原始数据分割为完整的掘进段,其次以掘进段为单位计算扭矩贯入指标(TPI),基于时间序列法和神经网络在掘进开始前对围岩质量进行预测,基于TPI的基尼不纯度,在掘进上升段对围岩质量进行判断。结果表明：TPI能够较好地反映围岩地质条件,基于时间序列法和神经网络能够较为准确地对TPI进行预测,通过TPI的基尼不纯度能够较好地对围岩质量进行判断。     

电力系统广域后备保护中的贝叶斯网故障诊断方法

提出一种广域后备保护中的基于贝叶斯网的故障诊断方法,将传统保护测量元件的动作信号作为证据,权衡证据信息量、诊断模型规模与诊断实时性要求来划分诊断区,分析了保护误动、拒动的随机特性,根据各保护的保护范围的特点,建立诊断区故障诊断模型。算例结果表明该方法正确、有效,具有较强的容错能力。     

An Optimization Approach for Multi-Sectoral Water Supply Management in the Greater Beirut Area

This paper presents a model that was developed and applied to serve as a water supply multi-sectoral decision support system for water resources management taking economic and socio-environmental factors into consideration. The applicability of the model was tested in the Greater Beirut Area by examining future supply-demand management alternatives and quantifying the cost-benefit of viable policies. The effect of eliminating a particular source to account for resources depletion and public acceptability, as well as increased returns from water use were proven to affect greatly the water allocation scheme. The model can also be a useful tool to assess the effect of decreasing unit costs from water supply options (desalination) and the resulting breakeven point, and the effect of increased water demand due to unplanned growth (tourism).     

基于指标权重的喀斯特地区水资源承载力评价

采用向量夹角余弦法和均方差法确定指标权重,运用多目标灰色关联投影法对贵州省各地区的水资源承载力进行了排序.     

基于水质目标的洞庭湖区堤垸生态需水量研究

洞庭湖区堤垸众多,垸内水体富营养化严重,水体流通不畅且水文观测资料匮乏,导致垸内生态需水量难以计算。以洞庭湖北部地区25个堤垸为研究对象,以垸内水体3 a后达到Ⅲ类水质为目标,在实地调研和勘查的基础上设置88个地表水水质采样点监测氨氮污染物浓度。基于环境稀释水量法建立了堤垸生态需水量计算模型,经与换水周期法对比分析,得到补水条件下洞庭湖北部地区堤垸生态需水量为32.161亿m³。研究成果对改善洞庭湖区垸内生态环境具有重要参考价值。     

基于Shapley-Value的梯级水库联合调度效益分配方法探讨

目前梯级水库在联合调度时由于补偿效益分配制度上的不合理,致使一些调节性能较好的电站在联合调度过程中得不到公正的对待,从而影响了这些电站对联合调度的积极性.针对上述问题,以三峡梯级和清江梯级五库联合调度为例,引入博弈论中的Shapley-Value法对联合调度所产生效益分配方法问题进行了探讨.结果表明:该方法不仅具有很强...     

New Approaches for Estimation of Monthly Rainfall Based on GEP-ARCH and ANN-ARCH Hybrid Models

Accurate estimation of rainfall has an important role in the optimal water resources management, as well as hydrological and climatological studies. In the present study, two novel types of hybrid models, namely gene expression programming-autoregressive conditional heteroscedasticity (GEP-ARCH) and artificial neural networks-autoregressive conditional heteroscedasticity (ANN-ARCH) are introduced to estimate monthly rainfall time series. To fulfill this purpose, five stations with various climatic conditions were selected in Iran. The lagged monthly rainfall data was utilized to develop the different GEP and ANN scenarios. The performance of proposed hybrid models was compared to the GEP and ANN models using root mean square error (RMSE) and coefficient of determination (R²). The results show that the proposed GEP-ARCH and ANN-ARCH models give a much better performance than the GEP and ANN in all of the studied stations with various climates. Furthermore, the ANN-ARCH model generally presents better performance in comparison with the GEP-ARCH model.     

An Ultimatum Game Theory Based Approach for Basin Scale Water Allocation Conflict Resolution

Increasing water consumption via competitive demands has resulted in serious water conflicts and the subsequent environmental crisis in the Gavkhouni Watershed with the Gavkhouni swamp in the most downstream located in the central part of Iran. In this research, a two-player ultimatum game theory approach is adopted to not only address the water conflicts with the purpose of environmental reclamation of the drying swamp, but also to ensure economic satisfaction for the upstream landowners and farmers. The Ministry of Energy (MoE) and its subsidiary regional water authority represent the responsible organizations for providing water while the Ministry of Agriculture (MoA) is the primary body in charge of water consumption in the watershed. MoE and MoA are considered as two players in the game, whereas MoE has more power than MoA in terms of allocating water. Five strategies are studied namely: 1 and 2) decreasing water allocation to irrigated agriculture as much as the annual shortage of the Gavkhouni swamp with and without compensation to MoA (D-L), 3 and 4) decreasing water allocation to irrigated agriculture twice as much the annual shortage of the swamp with and without compensation for MoA (D-2 L) and 5) giving up Gavkhouni swamp’s reclamation plan (D). Moreover, three scenarios regarding the relations between environmental and agricultural utilities are designated. According to the results, D-2 L with paying compensation to MoA is chosen as the best alternative in scenario 1 when the environmental utility was assumed to be greater than the agricultural utility. Ultimatum Game Theory has no final solution for scenarios 2 and 3 where the environmental utility is considered to be equal and smaller than agricultural utility. The swamp’s annual environmental water shortage as 324 million cubic meters is supplied by application of both strategies D-L and D-2 L. Ultimatum Games are efficient in assessment of water conflicts to resolve them through careful and planned negotiations.     

Combination of Multiple Data-Driven Models for Long-Term Monthly Runoff Predictions Based on Bayesian Model Averaging

Water Resources Management - Accurate and reliable long-term runoff forecasting is very important for water resource system planning and management. This study utilized three data-driven models to...     

考虑震损指标相关性的重力坝地震易损性分析

针对采用弹性损伤模型进行重力坝地震易损性分析效率较低的问题,分别采用线弹性模型和弹性损伤模型对重力坝进行动力时程分析,获得相应的线弹性震损指标(超应力单峰面积)和弹性损伤震损指标(损伤指数),建立了单峰面积与损伤指数之间的相关关系。提出了一种基于单峰面积与损伤指数相关性的地震易损性分析方法,即用线弹性动力计算得到的单峰面积近似估计坝体损伤指数,进而确定重力坝震损等级,以及超过各震损等级的概率,最后拟合出地震易损性曲线。将该方法应用于某重力坝的地震易损性分析,计算结果符合一般规律,计算效率得到极大提高。     

基于3次谐波无源注入法的谐波抑制技术

介绍了3次谐波注入抑制不可控整流电路进线电流谐波畸变的无源实现方法。采用Y接法电容器代替接地变压器作为3次谐波注入电路，并采用串联谐振电路提高3次注入电流的发生效率。分析了注入电路抑制进线电流谐波畸变的基本原理和谐波源的获得，研究了注入电路的基本特性，包括最佳注入条件、参数偏离谐振点的影响，以及固定注入电路参数条件下负载的动态变化范围等。实验结果表明，该方法具有比无源滤波更好的谐波抑制效果、比有源滤波更简单可靠的优点，应用前景较好。     

基于Q-S实测数据的群桩沉降简化分析

群桩沉降预测一直是桩基设计中的难点。本文通过对桩端桩侧性状进行分析,提出了一种群桩沉降简化分析方法。该法直接利用单桩试验预测群桩沉降,把桩端桩侧的荷载位移关系从单桩试验中分开,进而提出了桩端沉降比和桩侧沉降比并给出了计算公式。在工作荷载作用下桩端沉降比小于桩侧沉降比,如果把两者等同则夸大了群桩沉降;对有软弱下卧层的情况来说,桩端沉降比可能比桩侧沉降比大,进而高估了群桩沉降。最后通过实例对本文提出的方法进行了验证,表明本文方法切实可行。     

A Hybrid Model Based on Variational Mode Decomposition and Gradient Boosting Regression Tree for Monthly Runoff Forecasting

Water Resources Management - Accurate and reliable monthly runoff forecasting is of great significance for water resource optimization and management. A neoteric hybrid model based on variational...