Multiobjective optimization of the groundwater exploitation layout in coastal areas based on multiple surrogate models

2020 ◽  
Vol 27 (16) ◽  
pp. 19561-19576
Author(s):  
Yue Fan ◽  
Wenxi Lu ◽  
Tiansheng Miao ◽  
Jiuhui Li ◽  
Jin Lin
Keyword(s):  
Multiobjective Optimization ◽  
Surrogate Models ◽  
Coastal Areas ◽  
Groundwater Exploitation ◽  
Multiple Surrogate Models

Shape Optimization of Turbomachinery Blade Using Multiple Surrogate Models

2006 ◽  
Author(s):  
Abdus Samad ◽  
Kwang-Yong Kim ◽  
Tushar Goel ◽  
Raphael T. Haftka ◽  
Wei Shyy
Keyword(s):  
Shape Optimization ◽  
Cost Benefit Analysis ◽  
Weighted Average ◽  
Cost Benefit ◽  
Network Models ◽  
Surrogate Models ◽  
Fractional Factorial ◽  
Neural Network Models ◽  
Optimal Point ◽  
Multiple Surrogate Models

Performances of multiple surrogate models are evaluated in a turbomachinery blade shape optimization. The basic models, i.e., Response Surface Approximation, Kriging and Radial Basis Neural Network models as well as weighted average models are tested for shape optimization. Global data based errors for each surrogates are used to calculate the weights. These weights are multiplied with the respective surrogates to get the final weighted average models. Sequential Quadratic Programming is used to search the optimal point from these constructed surrogates. Use of multiple surrogates via weighted averaged surrogates gives more robust approximation than individual surrogates. Three design variables are selected to enhance the performance of transonic axial compressor (NASA rotor 37) blade and the design points are selected using three level fractional factorial D-optimal designs. The performance of compressor is improved by optimization because of reduction of losses and movement of separation line towards down stream directions. The present approach can help address the multi-objective design on a rational basis with quantifiable cost-benefit analysis.

scholarly journals Understanding Land Subsidence Along the Coastal Areas of Guangdong, China, by Analyzing Multi-Track MTInSAR Data

2020 ◽  
Vol 12 (2) ◽  
pp. 299 ◽  
Author(s):  
Yanan Du ◽  
Guangcai Feng ◽  
Lin Liu ◽  
Haiqiang Fu ◽  
Xing Peng ◽  
...  
Keyword(s):  
Land Subsidence ◽  
Coastal Areas ◽  
Alos Palsar ◽  
Groundwater Exploitation ◽  
Average Deformation ◽  
Deformation Velocity ◽  
Multi Temporal ◽  
Small Baseline Subset ◽  
Small Baseline ◽  
The Stability

Coastal areas are usually densely populated, economically developed, ecologically dense, and subject to a phenomenon that is becoming increasingly serious, land subsidence. Land subsidence can accelerate the increase in relative sea level, lead to a series of potential hazards, and threaten the stability of the ecological environment and human lives. In this paper, we adopted two commonly used multi-temporal interferometric synthetic aperture radar (MTInSAR) techniques, Small baseline subset (SBAS) and Temporarily coherent point (TCP) InSAR, to monitor the land subsidence along the entire coastline of Guangdong Province. The long-wavelength L-band ALOS/PALSAR-1 dataset collected from 2007 to 2011 is used to generate the average deformation velocity and deformation time series. Linear subsidence rates over 150 mm/yr are observed in the Chaoshan Plain. The spatiotemporal characteristics are analyzed and then compared with land use and geology to infer potential causes of the land subsidence. The results show that (1) subsidence with notable rates (>20 mm/yr) mainly occurs in areas of aquaculture, followed by urban, agricultural, and forest areas, with percentages of 40.8%, 37.1%, 21.5%, and 0.6%, respectively; (2) subsidence is mainly concentrated in the compressible Holocene deposits, and clearly associated with the thickness of the deposits; and (3) groundwater exploitation for aquaculture and agricultural use outside city areas is probably the main cause of subsidence along these coastal areas.

A Study on the Use of Multiple Surrogate Models in Valve Design

2012 ◽  
Vol 14 (1) ◽  
pp. 175-180 ◽  
Author(s):  
Xueguan Song ◽  
Youngchul Park
Keyword(s):  
Surrogate Models ◽  
Valve Design ◽  
Multiple Surrogate Models

scholarly journals Uncertainty Analysis in the Optimization Process of Groundwater Exploitation Scheme Based on SVR Method—A Case Study of Hetao Plain

2018 ◽  
Author(s):  
Yongkai An ◽  
Wenxi Lu ◽  
Xueman Yan
Keyword(s):  
Uncertainty Analysis ◽  
Simulation Model ◽  
Optimization Model ◽  
Surrogate Model ◽  
Surrogate Models ◽  
Groundwater Table ◽  
Pumping Rate ◽  
Groundwater Exploitation ◽  
Computational Load ◽  
Hetao Plain

This paper introduces a surrogate model to reduce the huge computational load in the process of simulation-optimization and uncertainty analysis. First, the groundwater numerical simulation model was established, calibrated and verified in the northeast of Hetao Plain. Second, two surrogate models of simulation model were established using support vector regression (SVR) method, one (surrogate model A, SMA) was used to describe the corresponding relationship between the pumping rate and average groundwater table drawdown, and another (surrogate model B, SMB) was used to express the corresponding relationship between the hydrogeological parameter values and average groundwater table drawdown. Third, an optimization model was established to search an optimal groundwater exploitation scheme using the maximum total pumping rate as objective function and the limitative average groundwater table drawdown as constraint condition, the SMA was invoked by the optimization model for obtaining the optimal groundwater exploitation scheme. Finally, the SMB was invoked in the process of uncertainty analysis for assessing the reliability of optimal groundwater exploitation scheme. Results show that the relative error and root mean square error between simulation model and the two surrogate models are both less than 5%, which is a high approximation accuracy. The SVR surrogate model developed in this study could not only considerably reduce the computational load, but also maintain high computational accuracy. The optimal total pumping rate is 7947 m3/d and the reliability of optimal scheme is 40.21%. This can thus provide an effective method for identifying an optimal groundwater exploitation scheme and assessing the reliability of scheme quickly and accurately.

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