为了从DNA分子水平探讨二倍体青檀(2n=2x=18)与经秋水仙素诱变获得的同源四倍体青檀(2n=4x=36)在遗传结构上的差异,本研究以2x及同源4x青檀为实验材料,利用AFLP(Amplified Fragment Length Polymorphism)分子标记技术,对供试材料的DNA...为了从DNA分子水平探讨二倍体青檀(2n=2x=18)与经秋水仙素诱变获得的同源四倍体青檀(2n=4x=36)在遗传结构上的差异,本研究以2x及同源4x青檀为实验材料,利用AFLP(Amplified Fragment Length Polymorphism)分子标记技术,对供试材料的DNA多态性及遗传距离进行分析。结果表明:经秋水仙素诱变获得的同源4x青檀与2x青檀在DNA分子遗传结构上具有显著差异,2x青檀单株间DNA多态性大于同源4x青檀,4x青檀单株间遗传距离在总体水平上大于2x青檀。本研究结果为进一步开展青檀多倍体育种、发挥青檀多倍体的优势提供理论依据。展开更多
The exponential p-moment stability of stochastic impulsive differential equations is addressed. A new theorem to ensure the p-moment stability is established for the trivial solution of the stochastic impul- sive diff...The exponential p-moment stability of stochastic impulsive differential equations is addressed. A new theorem to ensure the p-moment stability is established for the trivial solution of the stochastic impul- sive differential system. As an application of the theorem proposed, the problem of controlling chaos of Lorenz system which is excited by parameter white-noise excitation is considered using impulsive control method. Finally, numerical simulation results are given to verify the feasibility of our approach.展开更多
In this paper, the impacts of the recycled signal on the dynamic complexity have been studied theoretically and numerically in a prototypical nonlinear dynamical system. The Melnikov theory is employed to determine th...In this paper, the impacts of the recycled signal on the dynamic complexity have been studied theoretically and numerically in a prototypical nonlinear dynamical system. The Melnikov theory is employed to determine the critical boundary, and the statistical complexity measure(SCM) is defined and calculated to quantify the dynamic complexity. It has been found that one can switch the dynamics from the periodic motion to a chaotic one or suppress the chaotic behavior to a periodic one, merely via adjusting the time delay or the amplitude of the recycled signal, therefore, providing a candidate to tame the dynamic complexity in nonlinear dynamical systems.展开更多
误用检测由于其检测率高、误报率低,是目前入侵检测系统主要采用的技术。攻击模式作为判定网络行为是攻击行为还是正常行为的依据,因此,攻击模式的获知是当前误用检测的研究热点之一。基于入侵行为和正常行为具有不同的数据特征,可以把...误用检测由于其检测率高、误报率低,是目前入侵检测系统主要采用的技术。攻击模式作为判定网络行为是攻击行为还是正常行为的依据,因此,攻击模式的获知是当前误用检测的研究热点之一。基于入侵行为和正常行为具有不同的数据特征,可以把入侵行为数据看成是异常数据这一思想,提出一种基于最大频繁项目集的孤立点挖掘算法,生成攻击模式规则。通过KDD CUP 99数据集对提出的方法进行评估,并与其他算法进行对比,表明该方法具有更好的检测率和误报率。展开更多
文摘为了从DNA分子水平探讨二倍体青檀(2n=2x=18)与经秋水仙素诱变获得的同源四倍体青檀(2n=4x=36)在遗传结构上的差异,本研究以2x及同源4x青檀为实验材料,利用AFLP(Amplified Fragment Length Polymorphism)分子标记技术,对供试材料的DNA多态性及遗传距离进行分析。结果表明:经秋水仙素诱变获得的同源4x青檀与2x青檀在DNA分子遗传结构上具有显著差异,2x青檀单株间DNA多态性大于同源4x青檀,4x青檀单株间遗传距离在总体水平上大于2x青檀。本研究结果为进一步开展青檀多倍体育种、发挥青檀多倍体的优势提供理论依据。
基金Supported by the National Natural Science Foundation of China (Grant No. 10772046)
文摘The exponential p-moment stability of stochastic impulsive differential equations is addressed. A new theorem to ensure the p-moment stability is established for the trivial solution of the stochastic impul- sive differential system. As an application of the theorem proposed, the problem of controlling chaos of Lorenz system which is excited by parameter white-noise excitation is considered using impulsive control method. Finally, numerical simulation results are given to verify the feasibility of our approach.
基金supported by the National Natural Science Foundation of China(Grant No.11272258)the NPU Foundation for Fundamental Research
文摘In this paper, the impacts of the recycled signal on the dynamic complexity have been studied theoretically and numerically in a prototypical nonlinear dynamical system. The Melnikov theory is employed to determine the critical boundary, and the statistical complexity measure(SCM) is defined and calculated to quantify the dynamic complexity. It has been found that one can switch the dynamics from the periodic motion to a chaotic one or suppress the chaotic behavior to a periodic one, merely via adjusting the time delay or the amplitude of the recycled signal, therefore, providing a candidate to tame the dynamic complexity in nonlinear dynamical systems.
文摘误用检测由于其检测率高、误报率低,是目前入侵检测系统主要采用的技术。攻击模式作为判定网络行为是攻击行为还是正常行为的依据,因此,攻击模式的获知是当前误用检测的研究热点之一。基于入侵行为和正常行为具有不同的数据特征,可以把入侵行为数据看成是异常数据这一思想,提出一种基于最大频繁项目集的孤立点挖掘算法,生成攻击模式规则。通过KDD CUP 99数据集对提出的方法进行评估,并与其他算法进行对比,表明该方法具有更好的检测率和误报率。
