判定线性偏微分方程组解的完备性的一个符号计算方法

从微分代数的角度出发，借助于吴微分特征集理论，对于线性偏微分方程组，给出了判定它的解的完备性的一个符号计算方法。这个算法是一个机械化的算法，借助于符号计算软件Maple，可以在计算机上实现。     

Cross Soliton-Like Waves for the （2＋1）-Dimensional Breaking Soliton Equation

We construct a two-soliton-like solution for the （2＋1）-dimensionai breaking soliton equation. The obtained solution contains two arbitrary functions and hence can model various cross soliton-like waves including the two-solitary waves. We show the evolution of some special cross soliton-like waves diagrammatically.     

SIMILARITY REDUCTIONS FOR THE NONLINEAR EVOLUTION EQUATION ARISING IN THE FERMI-PASTA-ULAM PROBLEM

ＩｎｔｒｏｄｕｃｔｉｏｎＦｅｒｍｉ,ＰａｓｔａａｎｄＵｌａｍ[1]ｐｒｅｓｅｎｔｅｄａｗｅｌｌ＿ｋｎｏｗｎｐｒｏｂｌｅｍｗｈｙｓｏｌｉｄｓｈａｄｆｉｎｉｔｅｈｅａｔｃｏｎｄｕｃｔｉｖｉｔｙ ,ｗｈｉｃｈｗａｓｃａｌｌｅｄｔｈｅＦｅｒｍｉ＿Ｐａｓｔａ＿Ｕｌａｍ(ＦＰＵ)ｐｒｏｂｌｅｍ .Ｔｈｅｓｏｌｉｄｉｓｍｏｄｅｌｌｅｄｂｙａｏｎｅ＿ｄｉｍｅｎｓｉｏｎａｌｌａｔｔｉｃｅ ,ａｓｅｔｏｆｍａｓｓｅｓｃｏｕｐｌｅｄｂｙｓｔｒｉｎｇ .Ｔｈｅｅｑｕａｔｉｏｎｓｇｏｖｅｒｎｉｎｇｔｈｅｄｙｎａｍｉｃｓｏｆｔｈｉｓｌａ…     

Using symbolic computation to construct travelling wave solutions to nonlinear partial differential equations

Based upon the symbolic computation and the coupled projective Riccati equation, the tanh function method is further improved. As its applications, Wu－Zhang equation (which describes a (2+1)-dimensional dispersive long wave) and the (1+1)-dimensional dispersive long wave equation obtained from Wu－Zhang equation by scaling transformation and symmetry reduction are chosen to illustrate the validity of the proposed approach.     

基于加权复杂网络的文本关键词提取

通过分析基于复杂网络的网络提取的文本关键词新算法.首先根据文本特征词之间的关系构建文本的加权复杂网络模型,其次通过节点的加权聚类系数和节点的介数计算节点的综合特征值,最后根据综合特征值提取出文本关键词.实验结果表明,该算法提取的关键词能够较好地体现文本主题,提取关键词的准确率比已有算法有明显提高.     

变系数KdV-Burgers-Kuramoto方程的群论分析——容许变换及对称群

提出变系数KdV-Burgers-Kuramoto(VCKdVBK)方程$u_t+f(x,t)uu_x+g(x,t)u_{xx}+h(x,t)u_{xxx}+k(x,t)u_{xxxx}=0$的容许变换, 它不改变方程的形式但可能改变方程的系数$f, g, h$及$k$.然后, 基于这个容许变换, 给出了VCKdVBK方程的7种不同类型的等价类. 最后, 也给出了VCKdVBK方程的Lie点对称群.     

A SYMBOLIC COMPUTATION METHOD TO DECIDE THE COMPLETENESS OF THE SOLUTIONS TO THE SYSTEM OF LINEAR PARTIAL DIFFERENTIAL EQUATIONS

ＩｎｔｒｏｄｕｃｔｉｏｎＣｏｎｓｉｄｅｒｔｈｅｓｙｓｔｅｍｏｆｐａｒｔｉａｌｄｉｆｆｅｒｅｎｔｉａｌａｌｇｅｂｒａｉｃｅｑｕａｔｉｏｎｓ (ＰＤＡＥｓ) :Σ :　Ｐｉ(ｙ1,ｙ2 ,… ,ｙｎ) =0　　 (ｉ =1,2 ,… ,ｒ) ,ｗｈｅｒｅｔｈｅｃｏｅｆｆｉｃｉｅｎｔｓａｒｅｉｎｔｈｅｄｉｆｆｅｒｅｎｔｉａｌｆｉｅｌｄＫｗｉｔｈｃｈａｒａｃｔｅｒｉｓｔｉｃｚｅｒｏ .ＴｈｅｉｍｐｏｒｔａｎｔｑｕｅｓｔｉｏｎｉｓｈｏｗｔｏｓｏｌｖｅｔｈｉｓＰＤＡＥｓｉｎｔｈｅｔｈｅｏｒｙｏｆｐａｒｔｉａｌｄｉｆｆｅｒｅｎｔｉａｌｅｑｕａ…     

源于Fermi-Pasta-Ulam问题的非线性发展方程的相似约化

利用Clarkson和Kruskal引入的直接法和Lou的改进的直接法，给出了源于Fermi-Pasta-Ulam问题的非线性方程的4种类型的相似约化。