共查询到18条相似文献,搜索用时 125 毫秒
1.
2.
3.
4.
为了探讨水文模型参数优化结果在不同流域上的稳定性,采用SCE-UA算法优化了抚河流域内的娄家村、南丰、沙子岭子流域新安江日模型参数,以径流总量误差最小和纳什效率系数最大为目标函数,分别对参数优化结果进行分析。结果表明,其中有3个新安江日模型参数(上层张力水容量W_(WUM)、下层张力水容量W_(WLM)、张力水容量W_(WDM))在三个子流域上的率定结果的稳定性相差较大,有1个参数(表层自由水容量曲线方次E_(EX))率定结果有波动,剩余的12个参数的率定结果均较稳定。通过分析新安江日模型参数的稳定性,可为未来新安江模型参数优化的理论研究提供重要参考依据。 相似文献
5.
不同优化算法和目标函数组合将导致不同的模拟结果,进而影响流域水文预报精度。通过设定不同目标函数组合方案,对比汉江上游安康以上流域在多目标优化算法(NSGA-Ⅱ和MOPSO)下对HyMod模型性能评估的影响,并识别季尺度目标函数统计规律与模拟精度的本质联系。结果表明,NSGA-Ⅱ算法更适合于汉江流域(年尺度、季尺度模拟精度更优);模拟值与实测值的拟合误差控制函数和高流量误差控制的函数(F_2、F_3)为多目标模型参数校准的首选目标函数,其重要性大于水量模拟的误差控制函数和枯水流量的误差控制函数(F_1、F_4)。 相似文献
6.
7.
8.
9.
针对新安江水文模型参数的不确定性问题,以湘江湘潭断面控制流域为例,采用新安江日模型和两个纳什效率系数作为水文模型参数率定的目标函数,结合SCE-UA优化算法,分析了不同目标函数对实测径流的模拟能力,在此基础上进一步分析了单目标GLUE方法、多目标GLUE方法和NSGA-Ⅱ优化算法获得不确定性区间特征值。结果表明,不同目标函数对径流过程显示了不同的模拟性能;NSGA-Ⅱ算法可优化多目标拥有较小的不确定性区间,但区间对实测值的覆盖率较小;与单目标算法相比,在相同的区间宽度下,多目标GLUE方法具有更高的区间覆盖率。 相似文献
10.
11.
本文给出了PARMA模型的似然函数及模型参数的估计方法,引入了观测方程构成改进模型,并提出了偏态修正方法。用该模型生成了井岗山梯级水电站一级坝址处旬径流序列。 相似文献
12.
The objective of this article is to study the performance of iterative parameter and function estimation techniques to solve simultaneously two unknown functions (quadratic in time, and linear in time and space) using transient inverse heat conduction method in conjunction with a geometrical domain decomposition approach, in cylindrical coordinates. For geometrical decomposition of physical domain, a multi-block method has been used. The numerical scheme for the solution of the governing partial differential equations is the finite element method. The results of the present study for a configuration composed of two joined disks with different heights are compared to those of exact heat source and temperature boundary condition using inverse analysis. Good agreement between the estimated results and exact functions has been observed for parameter estimation techniques in contrast to those of function estimation approach. In summary, the results show that the function estimation technique is sensitive to the location of measurement points, but is useful to estimate unknown functions without a priori knowledge of the functions' spatial and/or temporal distributions. However, the function estimation technique suffers from a drawback: its implementation and data extraction are less straightforward than parameter estimation method. Finally, it is shown that the use of geometrical domain decomposition offers the possibility of developing a robust inverse analysis code for general purpose heat conduction problems. 相似文献
13.
Alireza Askarzadeh Mahdi Gharibi 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2018,40(24):2986-2999
Accurate parameter estimation of the input-output characteristics in thermal power plants is an important issue in power system because these characteristics directly affect the economic dispatch calculations. Parameter estimation is an optimization problem in which the optimal values of the unknown parameters should be estimated by an optimization technique. By considering the valve-point effect, the parameter estimation will be more difficult since the fitness function of this optimization problem turns into a non-smooth and non-convex function in which finding the global optimal is a challenging task. In this paper, a recently proposed metaheuristic approach, crow search algorithm (CSA), is proposed for accurate estimation of the input-output characteristics of thermal power plants with and without valve-point effect. Simulation results show that CSA finds more promising results than least squares method (LSM), particle swarm optimization (PSO), genetic algorithm (GA) and artificial bee colony (ABC). 相似文献
14.
15.
多变量水文联合分布方法及Copula函数的应用研究 总被引:1,自引:0,他引:1
简介了水文事件中的多变量联合分布计算方法,系统总结了Copula函数的原理、性质、水文计算中常用的函数类型、参数估计方法及拟合检验方法,探讨了Copula函数在水文方面的应用前景. 相似文献
16.
An inverse problem is solved for simultaneous three parameter estimation in a large-sized cylindrical fin involving conduction-convection heat transfer. The temperature field used for the estimation of unknowns is calculated from the finite difference method (FDM). The simulated annealing (SA) is applied in this work for minimizing the required objective function. The accuracy of the estimated parameters has been studied for different measurement points, initial guess, measurement errors, and number of iterations; CPU times are also reported. The FDM-SA is observed to reconstruct the temperature field with an excellent accuracy, but ill-posed behavior is observed. 相似文献
17.
SOC的准确估计对提高电池的动态性能和能量利用效率至关重要,估计过程中,模型参数不准确以及系统噪声的不确定性都会对结果产生较大影响。为减小模型参数辨识和系统噪声对SOC估计精度的影响,本文采用二阶RC等效电路模型,结合自适应扩展卡尔曼滤波算法(AEKF)进行锂电池的SOC估计。用带有遗忘因子的最小二乘法对模型参数进行在线辨识,以减小由参数辨识引起的估计误差,AEKF可以对系统和过程噪声进行修正,从而减小噪声对SOC估计的影响。最后分别用EKF和AEKF进行SOC估计并比较其误差,结果表明,AEKF联合最小二乘法参数在线辨识具有更高的精度和更好的适应性。 相似文献
18.
A new application of pattern search optimization technique for estimating the parameters of solar cell and PV module is introduced in this article. The estimated parameters are the generated photocurrent, saturation current, series resistance, shunt resistance, and ideality factor. A new objective function formulation is introduced to guide the estimation technique toward the model parameters. The proposed approach is tested and validated using different test cases, e. g. solar cell and PV module, to show its potential. Outcomes of the developed approach are compared with those of different parameter estimation techniques to measure its accuracy. Comparison results are in favor of pattern search algorithm in all cases. 相似文献