期刊文献+
共找到42篇文章
< 1 2 3 >
每页显示 20 50 100
番鸭部分生长性状遗传参数估计
1
作者 季从亮 张德祥 +1 位作者 李昂 罗庆斌 《养禽与禽病防治》 2013年第5期2-4,共3页
本研究以广东温氏南方家禽育种有限公司的番鸭N103品系第5世代公鸭为材料,测定77日龄时的体重、胫长和胫围等指标,结合第4世代、第5世代的系谱资料,估计体重、胫长和胫围等性状的遗传参数。结果显示,体重、胫长和胫围这3个性状属于中等... 本研究以广东温氏南方家禽育种有限公司的番鸭N103品系第5世代公鸭为材料,测定77日龄时的体重、胫长和胫围等指标,结合第4世代、第5世代的系谱资料,估计体重、胫长和胫围等性状的遗传参数。结果显示,体重、胫长和胫围这3个性状属于中等遗传的性状,遗传力估计值分别为0.292±0.075、0.309±0.081和0.322±0.075,体重与胫长、体重与胫围和胫长与胫围之间的遗传相关分别为0.537±0.174、0.458±0.156和0.484±0.165。 展开更多
关键词 遗传参 数体重 胫长 胫围
原文传递
SOI MOSFET Model Parameter Extraction via a Compound Genetic Algorithm 被引量:2
2
作者 李瑞贞 李多力 +2 位作者 杜寰 海潮和 韩郑生 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2006年第5期796-803,共8页
We improve the genetic algorithm by combining it with a simulated annealing algorithm. The improved algorithm is used to extract model parameters of SOI MOSFETs, which are fabricated with standard 1.2μm CMOS/SOI tech... We improve the genetic algorithm by combining it with a simulated annealing algorithm. The improved algorithm is used to extract model parameters of SOI MOSFETs, which are fabricated with standard 1.2μm CMOS/SOI technology developed by the Institute of Microelectronics of the Chinese Academy of Sciences. The simulation results using this model are in excellent agreement with experimental results. The precision is improved noticeably compared to commercial software. This method requires neither a deeper understanding of SOl MOSFETs model nor more complex computations than conventional algorithms used by commercial software. Comprehensive verification shows that this model is applicable to a very large range of device sizes. 展开更多
关键词 SOI parameter extraction genetic algorithm simulated annealing algorithm
下载PDF
Analysis on Combining Ability and Genetic Parameters of Main Agronomic Characters of 22 Maize Inbred Lines
3
作者 张亚勤 邱正高 +5 位作者 杨华 祁志云 汤玲 李淑君 张丕辉 袁亮 《Agricultural Science & Technology》 CAS 2015年第9期1907-1911,1915,共6页
The general combining ability(GCA), special combining ability(SCA) and genetic parameter of ten characters of 22 maize inbred lines including plant height and ear height were analyzed using 10×12 through inco... The general combining ability(GCA), special combining ability(SCA) and genetic parameter of ten characters of 22 maize inbred lines including plant height and ear height were analyzed using 10×12 through incomplete diallel cross(NC Ⅱ).The results showed that:(1) Among the 22 maize inbred lines, the yield GCAs of11 HN 097, 11 HN 099, 11 HN 105 and 11 HN 110 were high, which were elite inbred lines to collocate hybridized combinations with strong heterosis. The yield of11 HN110 × 11 HN097, 11 HN110 × 11 HN105, 11 HN112 × 11 HN 097 and 11 HN 106 × 11 HN 104 were in the first four place. The yielding abilities, adaptabilities and yielding stabilities of the four combinations can be further identified by experiment. The heredities of the ten characters were mainly controlled by additive gene effect whereas the influence of non-addictive gene effect was small. The narrow heritabilities of plant height, ear height, ear rows, ear length, kernels per row,100-grain weight and seed-producing percentage were more than 50%. The variances were mainly caused by heredity and early-generation selection should be conducted. The narrow heritabilities of ear diameter, bare tip length and yield was low, which should not be selected in early-generation. 展开更多
关键词 MAIZE Inbred line Combining ability Genetic parameter
下载PDF
Combining Ability and Correlation of Ear Characteristics of Twenty Maize Inbred Lines
4
作者 李淑君 董昕 +3 位作者 付忠军 祁志云 张丕辉 周汝平 《Agricultural Science & Technology》 CAS 2017年第9期1601-1606,共6页
The combining ability and correlation of eight ear characteristics in 99 maize hybrids generated by crossing nine female parents with 11 male parents were analyzed by incomplete diallel cross (NC II ) design. The re... The combining ability and correlation of eight ear characteristics in 99 maize hybrids generated by crossing nine female parents with 11 male parents were analyzed by incomplete diallel cross (NC II ) design. The results showed that the line F6 had the highest general combining ability (GCA) for yield, followed by F7, M3, M4 and M8. All of the five lines have great potential in maize breeding. The cross combination M3xF10 had the highest specific combining ability (SCA) for yield, showing strong heterosis. Heritability analysis of ear characteristics showed that GCA variance was higher than SCA variance in ear diameter, number of rows per ear and seed rate, and they were mainly controlled by the additive gene effect, indicating that that the selections for these traits are effective at early generations. The other three traits had lower SCA, for which the selections should be carried out at late generations. The correlation analysis revealed that ear length, number of grains per row, ear diameter, number of rows per ear, 100-seed weight and seed rate had extremely significant positive correlations with grain yield per plant. Among them, number of grains per row had the most significant effect on yield per plant. Barren tip length had a significant negative correlation with grain yield per plant. Therefore, we concluded that the combinations with more grains per row and shorter barren tip should be selected to achieve high yield of maize. 展开更多
关键词 MAIZE Inbred line Combining ability Ear characteristics Genetic parameters
下载PDF
On Genetic Parameter Estimation of Xinjiang Brown Cattle's Main Economic Characters
5
作者 周振勇 李红波 +3 位作者 闫向民 张金山 杜玮 张杨 《Agricultural Science & Technology》 CAS 2015年第8期1735-1740,共6页
The study aimed to determine the Xinjiang brown cattle's genetic param- eters of main growth and economic characters by using animal models and multiple traits derivative free restricted maximum likelihood (MTDFREML... The study aimed to determine the Xinjiang brown cattle's genetic param- eters of main growth and economic characters by using animal models and multiple traits derivative free restricted maximum likelihood (MTDFREML). Results showed that: the heritability values of Xinjiang brown cattle's growth characters, including birth weight, 6-month-age weight, one full year weight and 2-year-old weight, were 0.45, 0.37, 0.38 and 0.34, respectively, which were medium level. The heritability values of body measurement indexes of different ages were different, indexes such as one-year-old weight, 2-year-old weight, body slanting length and body height had comparatively strong phenotypic correlation and genetic correlation. It was suggested that the breeding work of Xinjiang brown cattle should focus on selecting major breeding objectives like body height and body slanting length. 展开更多
关键词 Xinjiang brown cattle Genetic parameters HERITABILITY
下载PDF
Genetic Parameters Evaluation of Main Reproductive Traits for the New Yorkshire Dam Line with High Prolificacy
6
作者 宋忠旭 孙华 +3 位作者 彭先文 李良华 董斌科 梅书棋 《Agricultural Science & Technology》 CAS 2013年第10期1465-1467,共3页
The genetic parameters of main reproductive traits for the new Yorkshire line with high prolificacy were evaluated by multiple animal model DFREML The re- suits showed that the heritability evaluates of the total numb... The genetic parameters of main reproductive traits for the new Yorkshire line with high prolificacy were evaluated by multiple animal model DFREML The re- suits showed that the heritability evaluates of the total number of born (TNB), alive number of born (ANB), litter weigh at birth (LWB) and litter weight at age of 21 days were 0.10, 0.15, 0.09 and 0.14, respectively. The genetic correlations between these traits, for example, the correlations between TNB/ANB, NB/LWB, TNB/LW21, ANB/LWB, ANB/LW21 and LWB/LW21 were 0.87, 0.74, 0.43, 0.69, 0.59 and 0.51, respectively. 展开更多
关键词 New Yorkshire dam line with high prolificacy DFREML Variance com- ponent Genetic parameter
下载PDF
Investigation on Genetic Characteristics of Salvia miltiorrhiza Bge. by Using cpSSR Technology
7
作者 王海 何冬梅 +3 位作者 王睿婷 宋杰 郭晓恒 严铸云 《Agricultural Science & Technology》 CAS 2012年第6期1157-1163,共7页
[Objective] This study aimed to analyze the genetic characteristics of Salvia miltiorrhiza by using cpSSR (chloroplast microsatellites) molecular marker method. [Method] Twelve pairs of SSR primers with ideal cpSSR ... [Objective] This study aimed to analyze the genetic characteristics of Salvia miltiorrhiza by using cpSSR (chloroplast microsatellites) molecular marker method. [Method] Twelve pairs of SSR primers with ideal cpSSR amplification result, good repeatability and clear amplification bands were selected for cpSSR detection and analysis of S. miltiorrhiza samples from 31 sampling locations in 25 counties of 8 provinces in China. [Result] S. miltiorrhiza shows an overall medium level in the cytoplasmic inheritance (cpSSR) and varying degrees of differences in the regions. Based on Shannon’s Information index (I) and Nei’s genetic diversity index, the cytoplasmic genetic diversity in different provinces shows a decreasing order of Shanxi, Henan, Shandong, Hebei, Sichuan, Jiangsu, Shaanxi, Anhui. Genetic variations of S. miltiorrhiza in eight provinces were found mainly among populations. Gene flow among populations with in a province is less than that among different provinces. [Conclusion] Comprehensive analysis shows that S. miltiorrhiza cultivated in genuine producing areas and traditional main producing areas are mainly introduced from the local before introduction of some foreign germplasm resources during cultivation. The exchange of S. miltiorrhiza germplasm resources exists very early among genuine producing areas such as Sichuan, Shandong and Henan, while S. miltiorrhiza germplasm resources in new producing areas are mainly introduced from genuine producing areas. However, no geographical correlation was observed in the genetic differentiation, which further reveals that there is a wide range of genetic exchange among S. miltiorrhiza germplasm resources in China, resulting from the artificial introduction from allopatry. 展开更多
关键词 Salvia miltiorrhiza Bunge CPSSR Molecular marker Genetic diversity
下载PDF
Small-Signal Equivalent Circuit Modeling of a Photodetector Chip 被引量:1
8
作者 苗昂 李轶群 +4 位作者 吴强 崔海林 黄永清 黄辉 任晓敏 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2007年第12期1878-1882,共5页
A small-signal equivalent circuit model and the ted. The equivalent lumped circuit, which takes the main extraction techniques for photodetector chips are presen- factors that limit a photodetector's RF performance i... A small-signal equivalent circuit model and the ted. The equivalent lumped circuit, which takes the main extraction techniques for photodetector chips are presen- factors that limit a photodetector's RF performance into consideration,is first determined based on the device's physical structure. The photodetector's S parameters are then on-wafer measured, and the measured raw data are processed with further calibration. A genetic algorithm is used to fit the measured data, thereby allowing us to calculate each parameter value of the model. Experimental resuits show that the modeled parameters are well matched to the measurements in a frequency range from 130MHz to 20GHz, and the proposed method is proved feasible. This model can give an exact description of the photodetector chip's high frequency performance,which enables an effective circuit-level prediction for photodetector and optoelectronic integrated circuits. 展开更多
关键词 small-signal equivalent circuit model of photodetector parameter extraction high frequency meas-urement genetic algorithm
下载PDF
Inverting reservoir parameters in a two-phase fractured medium with a niche genetic algorithm
9
作者 张生强 韩立国 +2 位作者 刘春成 张益明 巩向博 《Applied Geophysics》 SCIE CSCD 2012年第4期440-450,496,共12页
In this paper we calculate a synthetic medium surface displacement response that is consistent with real measurement data by applying the least-square principle and a niche genetic algorithm to the parameters inversio... In this paper we calculate a synthetic medium surface displacement response that is consistent with real measurement data by applying the least-square principle and a niche genetic algorithm to the parameters inversion problem of the wave equation in a two-phase medium. We propose a niche genetic multi-parameter (including porosity, solid phase density and fluid phase density) joint inversion algorithm based on a two-phase fractured medium in the BISQ model. We take the two-phase fractured medium of the BISQ model in a two- dimensional half space as an example, and carry out the numerical reservoir parameters inversion. Results show that this method is very convenient for solving the parameters inversion problem for the wave equation in a two-phase medium, and has the advantage of strong noise rejection. Relative to conventional genetic algorithms, the niche genetic algorithm based on a sharing function can not only significantly speed up the convergence, but also improve the inversion precision. 展开更多
关键词 Parameters inversion niche genetic algorithm BISQ model two-phase fracturedmedium wave equation
下载PDF
Estimate of Genetic Parameters of Grain Yield and Some Agronomic Traits in Durum Wheat Using Diallel Crosses 被引量:3
10
作者 Mohammad Ali Hussain AI-Falahy 《Journal of Agricultural Science and Technology(B)》 2013年第1期26-34,共9页
Five varieties of durum wheat were crossed in full diallel fashion through 2010/2011 growing season. The five parents and their 20 F1 progenies were grown in 2011/2012 at the farm of faculty of agricultural and forest... Five varieties of durum wheat were crossed in full diallel fashion through 2010/2011 growing season. The five parents and their 20 F1 progenies were grown in 2011/2012 at the farm of faculty of agricultural and forestry, Duhok university, Iraq, using randomize complete block design with three replications to estimate heterosis, heritability and some genetic parameters for yield and its components. The results showed highly significant difference among genotypes for all studied traits. The parent Um Raby-5 had a positive general combining ability effect for most traits including grain yield. The crosses (Kokorete71× LD - 357E), (Crezo × Um Rahy-5), (Cimeto×Um Raby-5), (Cimeto×crezo) and (Cimeto × Kokorete 71) exhibited significant desirable specific combining ability effect for most traits. The dominance was greater than additive almost traits. Heritability inbroad sense was high but heritability in narrow sense was low. The expected genetic advance as percent of traits mean was low for all traits. Most crosses showed significant positive heterosis for most traits and two crosses, (Crezo Cimeto) and (Cimeto Urn Raby-5) had the highest positive heterosis for the most studied traits including grain yield. 展开更多
关键词 Duhok FACULTY full diallcl HETEROSIS hcritability.
下载PDF
Inverse procedure for determining model parameter of soils using real-coded genetic algorithm 被引量:3
11
作者 李守巨 邵龙潭 +1 位作者 王吉喆 刘迎曦 《Journal of Central South University》 SCIE EI CAS 2012年第6期1764-1770,共7页
The hybrid genetic algorithm is utilized to facilitate model parameter estimation.The tri-dimensional compression tests of soil are performed to supply experimental data for identifying nonlinear constitutive model of... The hybrid genetic algorithm is utilized to facilitate model parameter estimation.The tri-dimensional compression tests of soil are performed to supply experimental data for identifying nonlinear constitutive model of soil.In order to save computing time during parameter inversion,a new procedure to compute the calculated strains is presented by multi-linear simplification approach instead of finite element method(FEM).The real-coded hybrid genetic algorithm is developed by combining normal genetic algorithm with gradient-based optimization algorithm.The numerical and experimental results for conditioned soil are compared.The forecast strains based on identified nonlinear constitutive model of soil agree well with observed ones.The effectiveness and accuracy of proposed parameter estimation approach are validated. 展开更多
关键词 parameter estimation real-coded genetic algorithm tri-dimensional compression test gradient-based optimization
下载PDF
Genetic variation in two sea cucumber (Apostichopus japonicus) stocks revealed by ISSR markers 被引量:3
12
作者 姚冰 胡晓丽 +2 位作者 包振民 陆维 胡景杰 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2007年第1期91-96,共6页
Sea cucumber Apostichopus japonicus samples were collected in Changdao, Penglai (PL), 27 individuals, and Lingshandao, Qingdao (QD), 30 individuals, in the Shandong Peninsula, China. Ten SSR primers were used to asses... Sea cucumber Apostichopus japonicus samples were collected in Changdao, Penglai (PL), 27 individuals, and Lingshandao, Qingdao (QD), 30 individuals, in the Shandong Peninsula, China. Ten SSR primers were used to assess the genetic variation and relationship between and within the two stocks. Respectively, for each stock, the percentage of polymorphic bands was 85.2% and 86.9%; the gene diver- sity was 0.360 5 and 0.342 8; and the Shannon’s information index was 0.515 0 and 0.499 0. At species level, the percentage of polymorphic bands was 92.2%, the total gene diversity was 0.378 9 and the Shannon’s information index was 0.550 4. The coefficient of overall genetic differentiation and the ge- netic distances between the stocks were also calculated to be 0.073 0 and 0.079 6 using the POPGENE program. Results show that the genetic diversity of the two stocks is still large but the genetic distance between the two stocks is close. A dendrogram was constructed for the 57 individuals from the two stocks, showing that the genetic structure was unitary for PL stock but complex for QD stock. 展开更多
关键词 sea cucumber Apostichopusjaponicus ISSR STOCK genetic diversity
下载PDF
GA-1DLCNN method and its application in bearing fault diagnosis 被引量:8
13
作者 Yang Zhenbo Jia Minping 《Journal of Southeast University(English Edition)》 EI CAS 2019年第1期36-42,共7页
Due to the fact that the vibration signal of the rotating machine is one-dimensional and the large-scale convolution kernel can obtain a better perception field, on the basis of the classical convolution neural networ... Due to the fact that the vibration signal of the rotating machine is one-dimensional and the large-scale convolution kernel can obtain a better perception field, on the basis of the classical convolution neural network model(LetNet-5), one-dimensional large-kernel convolution neural network(1 DLCNN) is designed. Since the hyper-parameters of 1 DLCNN have a greater impact on network performance, the genetic algorithm(GA) is used to optimize the hyper-parameters, and the method of optimizing the parameters of 1 DLCNN by the genetic algorithm is named GA-1 DLCNN. The experimental results show that the optimal network model based on the GA-1 DLCNN method can achieve 99.9% fault diagnosis accuracy, which is much higher than those of other traditional fault diagnosis methods. In addition, the 1 DLCNN is compared with one-dimencional small-kernel convolution neural network(1 DSCNN) and the classical two-dimensional convolution neural network model. The input sample lengths are set to be 128, 256, 512, 1 024, and 2 048, respectively, and the final diagnostic accuracy results and the visual scatter plot show that the effect of 1 DLCNN is optimal. 展开更多
关键词 one-dimensional convolution neural network large-size convolution kernel hyper-parameter optimization genetic algorithm
下载PDF
Selection for growth performance of tank-reared Pacific white shrimp, Litopenaeus vannamei
14
作者 安迪 刘小林 +1 位作者 黄皓 相建海 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2013年第3期534-541,共8页
Seven growth-related traits were measured to assess the selection response and genetic parameters of the growth of Pacific white shrimp, Litopenaeus vannamei, which had been domesticated in tanks for more than four ge... Seven growth-related traits were measured to assess the selection response and genetic parameters of the growth of Pacific white shrimp, Litopenaeus vannamei, which had been domesticated in tanks for more than four generations. Phenotypic and genetic parameters were evaluated and fitted to an animal model. Realized response was measured from the difference between the mean growth rates of selected and control families. Realized heritability was determined from the ratio of the selection responses and selection differentials. The animal model heritability estimate over generations was 0.44±0.09 for body weight (BW), and ranged from 0.21±0.08 to 0.37±0.06 for size traits. Genetic correlations of phenotypic traits were more variable (0.51-0.97), although correlations among various traits were high (>0.83). Across generations, BW and size traits increased, while selection response and heritability gradually decreased. Selection responses were 12.28%-23.35% for harvest weight and 3.58%-13.53% for size traits. Heritability estimates ranged from 0.34±0.09 to 0.48±0.15 for harvest weight and 0.17±0.01-0.38±0.11 for size traits. All phenotypic and genetic parameters differed between various treatments. To conclude, the results demonstrated a potential for mass selection of growth traits in L. vannamei. A breeding scheme could use this information to integrate the effectiveness constituent traits into an index to achieve genetic progress. 展开更多
关键词 growth performance Pacific white shrimp quantitative genetics realized heritability responseto selection
下载PDF
Genetic Determination and Selection of Sugarcane Families
15
作者 Shiyun TANG Rongzhong YANG +8 位作者 Lunwang WANG Baoqing ZHANG Yuchi DENG Cuifang YANG Shah ZHOU Wu XIAN Fang TAN Hongwei TAN Litao YANG 《Agricultural Science & Technology》 CAS 2017年第1期5-11,共7页
Sugarcane family evaluation on 108 hybridized combinations generated during 2013-2014 was conducted by measuring the main traits of plant and ratoon crops. Stalk height, stalk diameter, stalk number per stool and brix... Sugarcane family evaluation on 108 hybridized combinations generated during 2013-2014 was conducted by measuring the main traits of plant and ratoon crops. Stalk height, stalk diameter, stalk number per stool and brix were investigated in both plant cane and ratoon cane, while stalk weight per stool and brix weight per stool were measured only in plant cane. Genetic variation and genetic parameters of all traits were analyzed, and the families were evaluated based on comprehensive index method. The results showed that the stalk height of both plant and ratoon, stalk diameter of both plant and ratoon, stalk number per stool of plant, brix of both plant and ratoon, stalk weight per stool and brix weight per stool were sig- nificantly different among the families. Stalk height, stalk diameter, stalk number per stool of plant crop showed higher level of broad-sense heritability, genetic variation coefficient and relative genetic advance than those in ratoon crop. But there were no significant differences in broad-sense heritability, genetic variation coefficient and relative genetic advance of brix between plant and ratoon crops. Analysis of phenotypic and genotypic correlation showed that stalk weight per stool was significantly correlated with brix weight per stool, Fifteen elite families including Zhanzhe 74-141× CP72-1210, Guitang 05-3081×Yuetang 91-976, Yunzhe 02-588×ROC22, Funong 39× Guitang 03-1229, Guitang 02-901×Guitang 03-2357, Guitang 05-2743×Guitang 03- 1229, Guitang 92-66×ROC22, Dezhe 93-88×ROC22, Guitang 05-3445×Guitang 03- 2309, Yuetang 00-319×CP72-1210, Guitang 03-3089×ROC22, Yuetang 91-976×CP84- 1198, Yuefu 90-95 ×CP72-1210, Yunzhe 99-601×Guitang 00-122, Yuetang 00-236× ROC22 were selected based on comprehensive index method, and stalk weight per stool and brix weight per stool showed greater genetic gain. The families selected based on comprehensive index were not completely the same as the families selected by brix weight per stool, the rank correlation coefficient of the families selected based on comprehensive index and brix weight per stool was 0.748 (P〈0.01). 展开更多
关键词 Sugamane FAMILY Genetic parameter Index selection
下载PDF
Optimization of projectile aerodynamic parameters based on hybrid genetic algorithm
16
作者 刘霖 田晓丽 +2 位作者 高小东 甘桃元 佘新继 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2015年第4期364-367,共4页
Aerodynamic parameters are important factors that affect projectile flight movement. To obtain accurate aerodynamic parameters, a hybrid genetic algorithm is proposed to identify and optimize the aerodynamic parameter... Aerodynamic parameters are important factors that affect projectile flight movement. To obtain accurate aerodynamic parameters, a hybrid genetic algorithm is proposed to identify and optimize the aerodynamic parameters of projectile. By combining the traditional simulated annealing method that is easy to fall into local optimum solution but hard to get global parameters with the genetic algorithm that has good global optimization ability but slow local optimization ability, the hybrid genetic algo- rithm makes full use of the advantages of the two algorithms for the optimization of projectile aerodynamic parameters. The simulation results show that the hybrid genetic algorithm is better than a single algorithm. 展开更多
关键词 projectile aerodynamic parameters parameter optimization hybrid genetic algorithm
下载PDF
Effects of Trawl Selectivity and Genetic Parameters on Fish Body Length Under Long-Term Trawling
17
作者 YU Yang SUN Peng +4 位作者 CUI He SHENG Huaxiang ZHAO Fenfang TANG Yanli CHEN Zelin 《Journal of Ocean University of China》 SCIE CAS 2015年第5期835-840,共6页
Long-term fishing pressure affects the biological characteristics of exploited fish stocks. The biological characteristics of hairtail(Trichiurus lepturus) in the East China Sea are unable to recover because of long-t... Long-term fishing pressure affects the biological characteristics of exploited fish stocks. The biological characteristics of hairtail(Trichiurus lepturus) in the East China Sea are unable to recover because of long-term trawling. Fishing induces evolutionary effects on the fish's biological characteristics. Evidence of these changes includes small size at age, a shift to earlier age structure, and early maturation. Natural and artificial selection usually affect the fish's life history. Selection can induce different chances of reproduction, and individual fish can give a different genetic contribution to the next generation. In this study, analysis of time-dependent probability of significance and test of sensitivity were used to explore the effects of fish exploitation rate, mesh size, and heritability with long-term trawling. Results showed that fishing parameters were important drivers to exploited fish population. However, genetic traits altered by fishing were slow, and the changes in biological characteristics were weaker than those caused by fishing selection. Exploitation rate and mesh size exhibited similar evolutionary trend tendency under long-term fishing. The time-dependent probability of significance trend showed a gradual growth and tended to be stable. Therefore, the direction of fishing-induced evolution and successful management of fish species require considerable attention to contribute to sustainable fisheries in China. 展开更多
关键词 trawling pressure fish biological characteristics fishery management
下载PDF
Fractional order PID control for steer-by-wire system of emergency rescue vehicle based on genetic algorithm 被引量:7
18
作者 XU Fei-xiang LIU Xin-hui +2 位作者 CHEN Wei ZHOU Chen CAO Bing-wei 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第9期2340-2353,共14页
Aiming at dealing with the difficulty for traditional emergency rescue vehicle(ECV)to enter into limited rescue scenes,the electro-hydraulic steer-by-wire(SBW)system is introduced to achieve the multi-mode steering of... Aiming at dealing with the difficulty for traditional emergency rescue vehicle(ECV)to enter into limited rescue scenes,the electro-hydraulic steer-by-wire(SBW)system is introduced to achieve the multi-mode steering of the ECV.The overall structure and mathematical model of the SBW system are described at length.The fractional order proportional-integral-derivative(FOPID)controller based on fractional calculus theory is designed to control the steering cylinder’s movement in SBW system.The anti-windup problem is considered in the FOPID controller design to reduce the bad influence of saturation.Five parameters of the FOPID controller are optimized using the genetic algorithm by maximizing the fitness function which involves integral of time by absolute value error(ITAE),peak overshoot,as well as settling time.The time-domain simulations are implemented to identify the performance of the raised FOPID controller.The simulation results indicate the presented FOPID controller possesses more effective control properties than classical proportional-integral-derivative(PID)controller on the part of transient response,tracking capability and robustness. 展开更多
关键词 steer-by-wire system emergency rescue vehicle fractional order proportional-integral-derivative(FOPID)controller parameter optimization genetic algorithm
下载PDF
Parametric inversion of viscoelastic media from VSP data using a genetic algorithm 被引量:3
19
作者 Hu Bin Tang Gang Ma Jianwei Yang Huizhu 《Applied Geophysics》 SCIE CSCD 2007年第3期194-200,共7页
Viscoelastic parameters are becoming more important and their inversion algorithms are studied by many researchers. Genetic algorithms are random, self-adaptive, robust, and heuristic with global search and convergenc... Viscoelastic parameters are becoming more important and their inversion algorithms are studied by many researchers. Genetic algorithms are random, self-adaptive, robust, and heuristic with global search and convergence abilities. Based on the direct VSP wave equation, a genetic algorithm (GA) is introduced to determine the viscoelastic parameters. First, the direct wave equation in frequency is expressed as a function of complex velocity and then the complex velocities estimated by GA inversion. Since the phase velocity and Q-factor both are functions of complex velocity, their values can be computed easily. However, there are so many complex velocities that it is difficult to invert them directly. They can be rewritten as a function of Co and C∞ to reduce the number of parameters during the inversion process. Finally, a theoretical model experiment proves that our algorithm is exact and effective. 展开更多
关键词 viscoelastic parameter INVERSION genetic algorithm VSP data
下载PDF
Genetic Parameters for Yields and Reproductive Traits of Chinese Holstein Cows in Heilongjiang Province
20
作者 Kewei DING Takeo KAYABA 《Agricultural Science & Technology》 CAS 2013年第3期520-522,526,共4页
[Objective] This study aimed to estimate the genetic parameters for milk yield, fat percentage, fat yield and age at first freshening of Chinese Holsteins first lactation cows in Heilongjiang under frigid-temperature ... [Objective] This study aimed to estimate the genetic parameters for milk yield, fat percentage, fat yield and age at first freshening of Chinese Holsteins first lactation cows in Heilongjiang under frigid-temperature and temperature zone. [Method] Records of yield and reproduction from 8 868 Chinese Holstein first lacta- tion cows from 21 herds were utilized to evaluate genetic parameters for Hei- Iongjiangs' Chinese Holsteins. Restricted maximum likelihood (REML) method was used with an animal model. [Result] The heritabilities were 0.16 to 0.34 for yields and fat percentage, 0.38 for reproduction (age at the first freshening), which were similar to estimates for temperate areas from similar methods, except for constituent percentage. Also, the estimates of genetic correlation were high between milk yield and fat yield (0.97), but were low between milk yield and fat percentage (-0.24), age at the first freshening (-0.29) and generally antagonistic. [Conclusion] Thus, es- timates of genetic parameters in this frigid and frigid-temperate environment did not differ appreciably from those that occur in temperate dairy areas. 展开更多
关键词 Heilongjiang Chinese Holsteins PRODUCTION REPRODUCTION Genetic pa rameters
下载PDF
上一页 1 2 3 下一页 到第
使用帮助 返回顶部