排序方式: 共有12条查询结果,搜索用时 15 毫秒
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The integrability of a system of ODEs 圣=/(x1is defined as the existence of a sufficiently rich set of first integrals such that its solutions canbe expressed by these integrals.Here,a single-valued function西(。)is called a first integralof the system(1)if it is constant along any solution curve of the system(1).If≯(z)isdifferentiable,then this definition can be written as the condition (筹川瑚=0.The singularity analysis has been proved to be a successful tool for finding integrable systems… 相似文献
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W匕eonsider the existenee of single and multiple positive periodie solutions for the generalperiodie Logistie equation ,‘(t)=夕(t)!a(t)一f(t,夕(t一几(t)),…,夕(t一几,(t)))],t‘R,(E)wheref:Rx皿+’‘什矿15 eontinuous,a(t)〔C(皿,R+),瑞(亡)〔C(R,R),anda(t)=a(t+T),几二(t)=爪(t+T),饥=1,…,,z,f(t,。1,。2,…,。,,)=f(亡+T,。,,。2,…,。。),T>O· It 15 well known that many matliematieal eeologieal Logistie equations are related to tl、eequation(E),e.g.,(1)the single speeies periodie populatio,i ,,… 相似文献
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介绍了结构方程模型理论及其基本思想;并应用其理论,采用多指标综合评价方法,选取科研水平、人才建设、综合评价3个一级指标,国家重点学科数、核心期刊收录论文数和国家声誉等11个二级指标,基于基本能概括某省教育水平的25所高校的原始数据,将其标准化后,运用结构方程模型理论求解出各二级指标所占权重,再根据专家意见确定一级指标权重,通过加权平均方法求出高校综合得分,由高到低给出排名. 相似文献
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In this paper,we present a new technique to study nonlinear stochastic differential equations with periodic boundary value condition (in the sense of expectation).Our main idea is to decompose the stochastic process into a deterministic term and a new stochastic term with zero mean value.Then by using the contraction mapping principle and Leray-Schauder fixed point theorem,we obtain the existence theorem.Finally,we explain our main results by an elementary example. 相似文献
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给出了求解一类无界非凸区域上不动点问题的路径跟踪方法.在适当的条件下,给出了不动点存在性的构造性证明,从而得到了路径跟踪方法的全局收敛性结果.研究结果为计算无界非凸区域上不动点问题提供了一种全局收敛性方法. 相似文献
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The local existence and uniqueness of the solutions to backward stochastic differential equations(BSDEs, in short) driven by both fractional Brownian motions with Hurst parameter H ∈(1/2, 1) and the underlying standard Brownian motions are studied. The generalization of the It formula involving the fractional and standard Brownian motions is provided. By theory of Malliavin calculus and contraction mapping principle, the local existence and uniqueness of the solutions to BSDEs driven by both fractional Brownian motions and the underlying standard Brownian motions are obtained. 相似文献