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| 1 | Combination of sensitivity and uncertainty analyses for sediment transport modeling in sewer pipes显示文摘Mitigation of sediment deposition in lined open channels is an essential issue in hydraulic engineering practice.Hence,the limiting velocity should be determined to keep the channel bottom clean from sediment deposits.Recently,sediment transport modeling using various artificial intelligence(AI)techniques has attracted the interest of many researchers.The current integrated study highlights unique insight for modeling of sediment transport in sewer and urban drainage systems.A novel methodology based on the combination of sensitivity and uncertainty analyses with a machine learning technique is proposed as a tool for selection of the best input combination for modeling process at non-deposition conditions of sediment transport.Utilizing one to seven dimensionless parameters,127 models are developed in the current study.In order to evaluate the different parameter combinations and select the training and testing data,four strategies are considered.Considering the densimetric Froude number(Fr)as the dependent parameter,a model with independent parameters of volumetric sediment concentration(CV)and relative particle size(d/R)gave the best results with a mean absolute relative error(MARE)of 0.1 and a root means square error(RMSE)of 0.67.Uncertainty analysis is applied with a machine learning technique to investigate the credibility of the proposed methods.The percentage of the observed sample data bracketed by 95%predicted uncertainty bound(95PPU)is computed to assess the uncertainty of the best models. | Isa Ebtehaj Hossein Bonakdari Mir Jafar Sadegh Safari Bahram Gharabaghi Amir Hossein Zaji Hossien Riahi Madavar Zohreh Sheikh Khozani Mohammad Sadegh Es-haghi Aydin Shishegaran Ali Danandeh Mehr | 2020 | International Journal of Sediment Research2020，35，2： | 2 |
| 2 | An analysis of shear stress distribution in circular channels with sediment deposition based on Gene Expression Programming显示文摘Knowledge of the boundary shear stress distribution in channels is important because it is a key factor affecting on erosion and sedimentation rates. The presence of sediment deposits in sewers is often reported during operation, and circular channels are frequently used in sewer networks. Gene expression programming(GEP) is applied in this study to determine an equation for evaluating the shear stress distribution along the wetted perimeter of a circular channel with a flat bed, because of the presence of sediment on the bed. In view of the parameters affecting the shear stress distribution, five dimensionless parameters are applied to develop six GEP models to be used with 905 experimental data. The impact of the shear stress parameters is studied using the six GEP models and by dividing the wetted perimeter into wall and bed sections. Two equations are extracted from the GEP models' output to estimate wall and bed shear stresses. The best model results are compared with a well-known equation based on the entropy concept. The GEP model predictions of wall and bed shear stresses are very similar to the experimental outcomes, whereas the entropy-based model overestimates the shear stress distribution.The proposed GEP models demonstrate superior performance in estimating the shear stress distribution with a mean absolute percentage error(MAPE) of 3.79% compared to an existing equation with MAPE of 9.52%. | Zohreh Sheikh Khozani Hossein Bonakdari Isa Ebtehaj | 2017 | International Journal of Sediment Research2017，32，4： | 2 |
| 3 | 基于自清洁理念的下水道中沉积物运移的设计标准(英文)显示文摘研究目的:通过比较沉积物运移的不同标准,经选优得出更高精度的标准。创新要点:使用更少的参数和分情况来获得高精度的设计标准。研究方法:1.按状态将下水道中沉积物分成两类:没有沉淀的沉积物和沉淀的推移质;2.利用已有设计标准的方程,运用非线性回归和MINITAB软件,得到不同情况下的最佳方程式;3.用实验所得的值对各方程预测值进行验证,比较各方程式的预测精度。重要结论:1.本文提出的方程式可以预测不同情况下的沉积物运移;2.相比于其它标准,本文提出的方程式形式简单、所需参数少和参数估计简单,并且预测精度更高。 | Isa EBTEHAJ Hossein BONAKDARI Ali SHARIFI | 2014 | Journal of Zhejiang University-Science A(Applied Physics & Engineering)2014，15，11： | 2 |
| 4 | An expert system for predicting shear stress distribution in circular open channels using gene expression programming显示文摘The shear stress distribution in circular channels was modeled in this study using gene expression programming(GEP). 173 sets of reliable data were collected under four flow conditions for use in the training and testing stages. The effect of input variables on GEP modeling was studied and 15 different GEP models with individual, binary, ternary, and quaternary input combinations were investigated. The sensitivity analysis results demonstrate that dimensionless parameter y/P, where y is the transverse coordinate, and P is the wetted perimeter, is the most influential parameter with regard to the shear stress distribution in circular channels. GEP model 10, with the parameter y/P and Reynolds number(Re) as inputs, outperformed the other GEP models, with a coefficient of determination of 0.7814 for the testing data set. An equation was derived from the best GEP model and its results were compared with an artificial neural network(ANN) model and an equation based on the Shannon entropy proposed by other researchers. The GEP model, with an average RMSE of 0.0301, exhibits superior performance over the Shannon entropy-based equation, with an average RMSE of 0.1049, and the ANN model, with an average RMSE of 0.2815 for all flow depths. | Zohreh Sheikh Khozani Hossein Bonakdari Isa Ebtehaj | 2018 | Water Science and Engineering2018，11，2： | 1 |
| 5 | Determining the Scour Dimensions Around Submerged Vanes in a 180°Bend with the Gene Expression Programming Technique显示文摘Submerged vanes are installed on rivers and channel beds to protect the outer bank bends from scouring.Also,local scouring occurs around the submerged vanes over time,and identifying the effective factors on the scouring phenomena around these submerged vanes is one of the important issues in river engineering.The most important aimof this study is investigation of scour pattern around submerged vanes located in 180°bend experimentally and numerically.Firstly,the effects of various parameters such as the Froude number(Fr),angle of submerged vanes to the flow(α),angle of submerged vane location in the bend(θ),distance between submerged vanes(d),height(H),and length(L)of the vanes on the dimensionless volume of the scour hole were experimentally studied.The submerged vanes were installed on a 180°bend whose central radius and channel width were 2.8 and 0.6 m,respectively.By reducing the Froude number,the scour hole volume decreased.For all Froude numbers,the biggest scour hole formed atθ=15°.In all models,by increasing the Froude number,the scour hole volume significantly increases.In addition,by increasing the submerged vanes’length and height,the scour hole dimensions also grow.Secondly,using gene expression programming(GEP),a relationship for determining the scour hole volume around the submerged vanes was provided.For this model,the determination coefficients(R2)for the training and test modes were computed as 0.91 and 0.9,respectively.In addition,this study performed partial derivative sensitivity analysis(PDSA).According to the results,the PDSA was calculated as positive for all input variables. | Saeid Shabanlou Hamed Azimi Isa Ebtehaj Hossein Bonakdari | 2018 | Journal of Marine Science and Application2018，17，2： | 1 |
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