联合育种的准确性受到群体间遗传关联程度的影响。本研究通过比较基于系谱数据和基因组数据计算的群体遗传关联,探究高密度SNP标记在遗传关联估计中的应用前景。本研究同时使用了模拟数据和真实数据,采用6种不同的遗传关联计算方法,包括...联合育种的准确性受到群体间遗传关联程度的影响。本研究通过比较基于系谱数据和基因组数据计算的群体遗传关联,探究高密度SNP标记在遗传关联估计中的应用前景。本研究同时使用了模拟数据和真实数据,采用6种不同的遗传关联计算方法,包括PEVD(prediction error variance of differences)、PEVD(x)、VED(variance of estimated difference)、CD(generalized coefficient of determination)、r(prediction error correlation)和CR(connectedness rating),比较基于构建不同的关系矩阵(A、G、G_(s)、G_(0.5)和H矩阵)的群体间遗传关联。模拟数据和实际数据结果表明,除PEVD(x)和VED方法外,PEVD、CD、r和CR基于基因组信息的G、G_(s)和G_(0.5)阵计算的遗传关联程度均高于基于系谱信息的A阵,基于同时利用系谱和基因组信息的H阵遗传关联结果一般介于A阵与G阵之间。当CR和r为0时,CD都较高,高估了群体遗传关联。用r度量3个遗传分化程度不同的猪场间遗传关联时,基于G阵的r值均为0.01,不能准确反映群体真实遗传关联。随着遗传力的提高,所有群体遗传关联评估方法都有所改善,但遗传力为0.1时,PEVD基于A阵结果优于G阵,中高遗传力性状用于估计遗传关联优于低遗传力性状。本研究证明高密度SNP标记比系谱信息估计群体间遗传关联更有优势,CR是衡量遗传关联稳健而可靠的评价指标,计算简单,受性状遗传力影响较小。PEVD可以作为补充,量化具体群体遗传关联下的育种值预测误差情况。G矩阵比G_(s)、G_(0.5)阵能更好反映群体遗传关联。展开更多
Disassembly sequence planning （DSP） plays a significant role in maintenance planning of the aircraft. It is used during the design stage for the analysis of maintainability of the aircraft. To solve product disassem...Disassembly sequence planning （DSP） plays a significant role in maintenance planning of the aircraft. It is used during the design stage for the analysis of maintainability of the aircraft. To solve product disassembly sequence planning problems efficiently, a product disassembly hybrid graph model, which describes the connection, non-connection and precedence relationships between the product parts, is established based on the characteristic of disassembly. Farther, the optimization model is provided to optimize disassembly sequence. And the solution methodology based on the genetic/simulated annealing algorithm with binaxy-tree algorithm is given. Finally, an example is analyzed in detail, and the result shows that the model is correct and efficient.展开更多
The formulation of multibody dynamics was studied based on variational principle. The body coonection matrix was introduced to define the connection configuration. The expression for the system kinematics was obtained...The formulation of multibody dynamics was studied based on variational principle. The body coonection matrix was introduced to define the connection configuration. The expression for the system kinematics was obtained by using the body connection matrix. From variational principle the general dynamical equations for multibody system were derived and the dynamical equations were given for multibody system subjected to the constraints.展开更多
文摘联合育种的准确性受到群体间遗传关联程度的影响。本研究通过比较基于系谱数据和基因组数据计算的群体遗传关联,探究高密度SNP标记在遗传关联估计中的应用前景。本研究同时使用了模拟数据和真实数据,采用6种不同的遗传关联计算方法,包括PEVD(prediction error variance of differences)、PEVD(x)、VED(variance of estimated difference)、CD(generalized coefficient of determination)、r(prediction error correlation)和CR(connectedness rating),比较基于构建不同的关系矩阵(A、G、G_(s)、G_(0.5)和H矩阵)的群体间遗传关联。模拟数据和实际数据结果表明,除PEVD(x)和VED方法外,PEVD、CD、r和CR基于基因组信息的G、G_(s)和G_(0.5)阵计算的遗传关联程度均高于基于系谱信息的A阵,基于同时利用系谱和基因组信息的H阵遗传关联结果一般介于A阵与G阵之间。当CR和r为0时,CD都较高,高估了群体遗传关联。用r度量3个遗传分化程度不同的猪场间遗传关联时,基于G阵的r值均为0.01,不能准确反映群体真实遗传关联。随着遗传力的提高,所有群体遗传关联评估方法都有所改善,但遗传力为0.1时,PEVD基于A阵结果优于G阵,中高遗传力性状用于估计遗传关联优于低遗传力性状。本研究证明高密度SNP标记比系谱信息估计群体间遗传关联更有优势,CR是衡量遗传关联稳健而可靠的评价指标,计算简单,受性状遗传力影响较小。PEVD可以作为补充,量化具体群体遗传关联下的育种值预测误差情况。G矩阵比G_(s)、G_(0.5)阵能更好反映群体遗传关联。
基金supported by the National High Technology Research and Development Program of China(2006AA04Z427).
文摘Disassembly sequence planning （DSP） plays a significant role in maintenance planning of the aircraft. It is used during the design stage for the analysis of maintainability of the aircraft. To solve product disassembly sequence planning problems efficiently, a product disassembly hybrid graph model, which describes the connection, non-connection and precedence relationships between the product parts, is established based on the characteristic of disassembly. Farther, the optimization model is provided to optimize disassembly sequence. And the solution methodology based on the genetic/simulated annealing algorithm with binaxy-tree algorithm is given. Finally, an example is analyzed in detail, and the result shows that the model is correct and efficient.
基金Supported by the National 973 Plan project(2011CB706900)the National 863 Plan project(2011AA01A102)+1 种基金the NSFC(11331012,11571015)the "Strategic Priority Research Program" of Chinese Academy of Sciences(XDA06010302)
文摘The formulation of multibody dynamics was studied based on variational principle. The body coonection matrix was introduced to define the connection configuration. The expression for the system kinematics was obtained by using the body connection matrix. From variational principle the general dynamical equations for multibody system were derived and the dynamical equations were given for multibody system subjected to the constraints.
