共查询到20条相似文献,搜索用时 125 毫秒
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n阶微分方程三点边值问题 总被引:1,自引:0,他引:1
刘颖 《应用数学与计算数学学报》2001,15(1):29-36
用上、下解方法讨论了非线性n阶常微分方程满足三点全非线性边界条件的边值问题解的存在性和唯一性。 相似文献
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四阶非线性常微分方程非线性两点边值问题解的存在唯一性 总被引:2,自引:0,他引:2
裴明鹤 《高校应用数学学报(A辑)》1995,(3):285-294
本文利用Bolzano定理,给出了四阶非线性常微微分方程具有非线性边界条件的两点边值问题(1)(2)2,(1)(2)3存在解与存在唯一解的一般性结果,并将所得结果应用于Lipschiz方程,对Lipschitz方程满足边界条件(2)2,(2)3的边值问题给出了存在解与存在唯一解的具体的充分条件。 相似文献
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n阶非线性常微分方程两点及三点边值问题解的存在性的进一步结果 总被引:6,自引:0,他引:6
本文利用上、下解方法讨论了n阶非线性常微分方程y^(n)=f(t,y,y‘…,y^(n-1))满足下列非线性边界条件的边值问题解的存在性。 相似文献
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四阶椭圆方程解之极值原理最先由Dunninger,D.R.提出.Goyal,V.B.和Singl,K.P.推广到半线性方程的情形,文献[5]、[6]作进一步的推广,都对文献[3]的某些结论作了修正,并且都建立四阶椭圆方程边值问题解的存在性定理。关于四阶抛物方程解的极值原理及唯一性定理作者作过讨论。这篇短文研究四阶非线性抛物方程的初值问题和混合问题解的存在性,其前提是所有解的最大模有一致先验的上界。 相似文献
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本文利用上、下解方法讨论了几类n阶常微分方程三、四点非线性边值问题解的存在性和唯一性。 相似文献
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n阶非线性常微分方程的非线性两点边值问题 总被引:1,自引:1,他引:0
本文利用打靶法,给出了n阶非线性常微分方程具有非线性两点边界条件的边值问题存在解与存在唯一解的一般性结果,并将所得结果应用于Lipschitz方程的两点过值问题,给出了存在解与存在唯一解的具体的充分条件。 相似文献
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三阶非线性常微分方程非线性两点边值问题解的存在性与唯一性 总被引:2,自引:0,他引:2
本文得用Bolzano定理,给出了三阶非线性常微分方程具非线性两点边界条件的边值问题(1)(2)存在解与存在唯一解的一般结果,并将所得结果应用于Lipschitz方程,对Lipschitz方程满足(2),(3)的边值问题给出了解存在与存在唯一解的较具体的充分条件。 相似文献
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有资格限制的指派问题的求解方法 总被引:3,自引:0,他引:3
在实际的指派工作中,常会遇到某个人有没有资格去承担某项工作的问题,因此,本建立了有资格限制的指派问题的数学模型。在此数学模型中,将效益矩阵转化为判定矩阵,由此给出了判定此种指派问题是否有解的方法;在有解的情况下,进一步将效益矩阵转化为求解矩阵,从而将有资格限制的指派问题化为传统的指派问题来求解。最后给出了一个数值例子来说明这样的处理方法是有效的。 相似文献
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Jogi Henna 《Annals of the Institute of Statistical Mathematics》2005,57(4):655-664
An estimator of the number of components of a finite mixture ofk-dimensional distributions is given on the basis of a one-dimensional independent random sample obtained by a transformation
of ak-dimensional independent random sample. A consistency of the estimator is shown. Some simulation results are given in a case
of finite mixtures of two-dimensional normal distributions. 相似文献
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碾压混凝土坝施工层面变形分析模型 总被引:1,自引:0,他引:1
针对碾压混凝土坝施工层面对大坝变形产生显著影响的问题,深入研究了施工层面的变化性质及规律,提出了层面不同阶段变形的模拟方法,建立了施工层面有厚度和无厚度分析模型,提出的模型能反映层面的弹性变形、衰减蠕变、不可逆变形以及加速蠕变等变形状态.实例分析表明:所提出的碾压混凝土坝施工层面有厚度和无厚度分析模型能较客观地模拟大坝的结构变化形态,尤其是施工层面有厚度分析模型较完整地模拟了层面的渐变规律,其计算结果与原位监测成果吻合较好.同时,提出的方法和建立的分析模型可推广应用于常规混凝土坝,特别是坝基内断层和夹层等变形规律的分析. 相似文献
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N/Kbe a Galois extension of number fields with finite Galois group G.We describe a new approach for constructing invariants of the G-module structure of the K groups of the ring of integers of N in the Grothendieck group of finitely generated projective Z[G]modules. In various cases we can relate these classes, and their function field counterparts, to the root number class of Fröhlich and Cassou-Noguès. 相似文献
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The Gauss-Lucas Theorem on the roots of polynomials nicely simplifies the computation of the subderivative and regular subdifferential
of the abscissa mapping on polynomials (the maximum of the real parts of the roots). This paper extends this approach to more
general functions of the roots. By combining the Gauss-Lucas methodology with an analysis of the splitting behavior of the
roots, we obtain characterizations of the subderivative and regular subdifferential for these functions as well. In particular,
we completely characterize the subderivative and regular subdifferential of the radius mapping (the maximum of the moduli
of the roots). The abscissa and radius mappings are important for the study of continuous and discrete time linear dynamical
systems.
Dedicated to R. Tyrrell Rockafellar on the occasion of his 70th birthday. Terry is one of those rare individuals who combine
a broad vision, deep insight, and the outstanding writing and lecturing skills crucial for engaging others in his subject.
With these qualities he has won universal respect as a founding father of our discipline. We, and the broader mathematical
community, owe Terry a great deal. But most of all we are personally thankful to Terry for his friendship and guidance.
Research supported in part by the National Science Foundation Grant DMS-0203175.
Research supported in part by the Natural Sciences and Engineering Research Council of Canada.
Research supported in part by the National Science Foundation Grant DMS-0412049. 相似文献
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本文分析了15具白骨化尸体标本的股骨汞(Hg),铅(Pb),镉(Cd)元素含量数据,在三年的时间内采集了3次,一共收集到45个数据。首先将这组数据看着纵向数据,利用线性随机效应混合模型、Cox随机混合效应模型进行分析,结果显示,如果对每个白骨化尸体标本建立线性模型,可以精确预测出死亡时间,而且不需要采集铅元素含量数据。混合效应模型的预测效果也很好,最大误差不会超过1个月。其次我们对数据不作任何假设,利用机器学习中随机森林方法分析数据,并利用5折交叉验证方法来判断结果的可靠性,训练集和测试集的NMSE分别为0.1205944,0.5604286,因此可以用训练出的模型来预测死亡时间。 相似文献
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The aim of this paper is to establish the uniform convergence of the densities of a sequence of random variables, which are functionals of an underlying Gaussian process, to a normal density. Precise estimates for the uniform distance are derived by using the techniques of Malliavin calculus, combined with Stein?s method for normal approximation. We need to assume some non-degeneracy conditions. First, the study is focused on random variables in a fixed Wiener chaos, and later, the results are extended to the uniform convergence of the derivatives of the densities and to the case of random vectors in some fixed chaos, which are uniformly non-degenerate in the sense of Malliavin calculus. Explicit upper bounds for the uniform norm are obtained for random variables in the second Wiener chaos, and an application to the convergence of densities of the least square estimator for the drift parameter in Ornstein–Uhlenbeck processes is discussed. 相似文献
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In this paper we determine the minimum and maximum values of the sum of squares of degrees of bipartite graphs with a given number of vertices and edges. 相似文献
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Ph. Getto A. Marciniak-Czochra 《Journal of Mathematical Analysis and Applications》2008,344(2):821-850
Interferons are active biomolecules, which help fight viral infections by spreading from infected to uninfected cells and activate effector molecules, which confer resistance from the virus on cells. We propose a new model of dynamics of viral infection, including endocytosis, cell death, production of interferon and development of resistance. The novel element is a specific biologically justified mechanism of interferon action, which results in dynamics different from other infection models. The model reflects conditions prevailing in liquid cultures (ideal mixing), and the absence of cells or virus influx from outside. The basic model is a nonlinear system of five ordinary differential equations. For this variant, it is possible to characterise global behaviour, using a conservation law. Analytic results are supplemented by computational studies. The second variant of the model includes age-of-infection structure of infected cells, which is described by a transport-type partial differential equation for infected cells. The conclusions are: (i) If virus mortality is included, the virus becomes eventually extinct and subpopulations of uninfected and resistant cells are established. (ii) If virus mortality is not included, the dynamics may lead to extinction of uninfected cells. (iii) Switching off the interferon defense results in a decrease of the sum total of uninfected and resistant cells. (iv) Infection-age structure of infected cells may result in stabilisation or destabilisation of the system, depending on detailed assumptions. Our work seems to constitute the first comprehensive mathematical analysis of the cell-virus-interferon system based on biologically plausible hypotheses. 相似文献