A Novel Hybrid Intelligent Prediction Model for Valley Deformation: A Case Study in Xiluodu Reservoir Region, China

The narrowing deformation of reservoir valley during the initial operation period threatens the long-term safety of the dam,and an accurate prediction of valley deformation(VD)remains a challenging part of risk mitigation.In order to enhance the accuracy of VD prediction,a novel hybrid model combining Ensemble empirical mode decomposition based interval threshold denoising(EEMD-ITD),Differential evolutions—Shuffled frog leaping algorithm(DE-SFLA)and Least squares support vector machine(LSSVM)is proposed.The non-stationary VD series is firstly decomposed into several stationary subseries by EEMD;then,ITD is applied for redundant information denoising on special sub-series,and the denoised deformation is divided into the trend and periodic deformation components.Meanwhile,several relevant triggering factors affecting the VD are considered,from which the input features are extracted by Grey relational analysis(GRA).After that,DE-SFLA-LSSVM is separately performed to predict the trend and periodic deformation with the optimal inputs.Ultimately,the two individual forecast components are reconstructed to obtain the final predicted values.Two VD series monitored in Xiluodu reservoir region are utilized to verify the proposed model.The results demonstrate that:(1)Compared with Discrete wavelet transform(DWT),better denoising performance can be achieved by EEMD-ITD;(2)Using GRA to screen the optimal input features can effectively quantify the deformation response relationship to the triggering factors,and reduce the model complexity;(3)The proposed hybrid model in this study displays superior performance on some compared models(e.g.,LSSVM,Backward Propagation neural network(BPNN),and DE-SFLA-BPNN)in terms of forecast accuracy.

Morphological characteristics and genetic differentiation of Lutraria maxima in coast waters off southeast China

To explore genetic diversity and estimate the genetic differences among populations of Lutraria maxima in the coastal waters off south to southeast China,the morphology of the species of five different geographical populations(Beihai,Weizhou Island,Zhanjiang,Xiamen,and Fuzhou)in Guangxi,Guangdong,and Fujian provinces was studied statistically in combination with the microsatellite markers.As revealed by morphological principal component analysis(PCA),the cumulative contribution rate of the first three principal components was 72.596%.The discrimination accuracy ranged from 47.5%to 80.0%,and the scatter plots of principal component and discriminant analysis were consistent in overall,showing that the Xiamen and Fuzhou populations were overlapped obviously.For microsatellite markers,10 pairs of polymorphic primers were obtained by high-throughput transcriptome sequencing,and used for genetic diversity analysis.It was showed that the average number of alleles and eff ective alleles observed in each population ranged from 8.100 to 10.900,and from 3.497 to 4.228,respectively.The average observed heterozygosity(H_(o))and expected heterozygosity(H_(e))in the five populations ranged from 0.541 to 0.615,and from 0.642 to 0.733,respectively.The genetic distance(DA)ranged from 0.078 to 0.523,and the population genetic differentiation index(F_(ST))ranged from 0.027 to 0.139.The unweighted pair-population method with arithmetic means(UPGMA)and structure analysis showed that the five populations could be divided into two main clusters,the Beibu Gulf group(Beihai and Weizhou Island)and the Southeast China Sea group(Zhanjiang,Xiamen,and Fuzhou),suggesting that L.maxima has been separated geographically by the barrier of the Leizhou Peninsula into two groups in evolution,which provided us with a scientific clue to better protect the bioresource and establish an appropriate fishery management stocks for L.maxima populations in south China.

Side force control on slender body by self-excited oscillation flag

Strong asymmetrical vortices appear on the leeward of slender body at high angles of attack, which has very unfavorable effect on the stability and control of the aircraft. A method is developed to control the side force of slender body at high angles of attack, and is verified in wind tunnel. A thin-film triangular self-excited oscillation flag is fixed at the tip of the slender body model whose semi-apex angle is 10°. Side force is approximately linearly proportional to roll-setting angle of self-excited oscillation flag at high angles of attack, and the slop of fitting straight line obtained by the least square method is -0.158. The linear relationship between side force and roU-setting angle provides convenience for developing side force control law of slender body at high angles of attack. Experimental data shows that the side force coefficients vary linearly with roll-setting angles when a specific plastic self-excited oscillation flag is used as the control flag. The range of side force coefficient and roll-setting angle are, respectively, -3.2 to 3.0 and -20° to 20°. The device is simple, effective, and is of great potential in engineering application.

Morphometric analysis and fluorescent microsatellite markers to evaluate the genetic diversity of five populations of Penaeus japonicus in China

To understand the current status of germplasm resources of Penaeus japonicus,in this study,genetic diversity was analyzed based on morphometric analysis and fluorescent microsatellite markers.For morphometric analysis,the cumulative ratios of the PC1 and PC2(85.90%)were greater than 75%,which can explain the morphological variation among populations.For microsatellite analysis,the allele number in 10 microsatellite loci ranged from 27 to 53,and the effective allele number ranged from 21 to 42.The observed heterozygosity ranged from 0.463 to 0.983,whereas expected heterozygosity ranged from 0.932 to 0.966,and the average polymorphism information content was 0.947,which indicated a high level of genetic diversity.The unbiased genetic distance among populations ranged from 0.230 to 0.431,and the genetic similarity coefficient ranged from 0.654 to 0.782.Analysis of molecular variance(AMOVA)showed that the genetic variation within individuals was the main source of variation,accounting for 88.55%,and only 1.49%of the genetic variation came from among populations.