scholarly journals An improved two-step parameter adjustment method for the optimization of a reservoir operation function model based on repeated principal component analysis and a genetic algorithm

2018 ◽  
Vol 21 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Xuan Wang ◽  
Xiao Chen ◽  
Quan Cui ◽  
Zhifeng Yang

Abstract This paper presents an improved two-step parameter adjustment method for the construction of a reservoir operation function model, by using repeated principal component analysis (PCA) and a genetic algorithm (GA) to optimize parameters in conventional multiple regression models. The first step is to use repeated PCA, to exclude the co-linear parameters in a multiple regression expression reflecting relationships among possible impact factors of reservoir operation, so as to form an initial reservoir operation function model. The second step is to use a GA to optimize the model constructed in the first step, and to compare its effects with other regression methods. The results show that the proposed reservoir operation function model can produce better results, which correlate water volume for power generation, input discharge, water level, and ecological flow. Compared with established scheduling schemes, the optimized scheme increases the water volume for power generation by 1.06 × 109 m3/yr, and the optimized result generates an increase in economic benefits of 3.22 × 107 yuan/yr (i.e., 4.69 × 106 USD/yr).

2021 ◽  
Vol 1786 (1) ◽  
pp. 012056
Author(s):  
Huan Tian ◽  
Wenyong Dong ◽  
Yafen Xu ◽  
Yuan Gao ◽  
Cheng Fang

1992 ◽  
Vol 43 (7) ◽  
pp. 1559 ◽  
Author(s):  
PS Cocks

Attributes of 84 accessions of 12 medics (Medicago spp.) were measured in nursery rows in two successive years. Multiple regression, principal component, and cluster analyses were used to relate 14 attributes of the medics to persistence in the seed bank of grazed pasture growing in rotation with wheat. Principal component analysis distinguished between the attributes of the species. For example, M. rigidula had short petioles, high frost tolerance, many seeds per pod, and large leaves and seeds; while M. polymorpha had long petioles, low frost tolerance, few seeds per pod, and small seeds and leaves. M. noeana produced many flowers per raceme, small pods and seeds, long peduncles, and was hard-seeded and late flowering; while M. aculeata produced few flowers per raceme, large pods and seeds, short peduncles, and was soft-seeded and early flowering. M. trulncatula and M. rotata were intermediate. Long peduncles and high levels of hardseededness were the attributes most closely associated with persistence of the medics in grazed pasture. It was concluded that (1) long peduncles place the flowers above the canopy in spring where they are in full sun light, and (2) hardseededness levels of up to 90% protect seeds against germination in the cereal year. The results also suggest that small leaves and short internodes and petioles protect young plants against over-grazing in winter, and small pods and seeds are less likely than large pods and seeds to be selected and digested by grazing sheep in summer.


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