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一类带有一般接触率和常数输入的流行病模型的全局分析 总被引:12,自引:1,他引:11
借助极限系统理论和构造适当的Liapunov函数,对带有一般接触率和常数输入的SIR型和SIRS型传染病模型进行讨论.当无染病输入时,地方病平衡点存在的阈值被找到.对相应的SIR模型,关于无病平衡点和地方病平衡点的全局渐近稳定性均得到充要条件;对相应的SIRS模型.得到无病平衡点和地方病平衡点全局渐近稳定的充分条件.当有染病输入时,模型不存在无病平衡点.对相应的SIR模型,地方病平衡点是全局渐近稳定的;对相应的SIRS模型,得到地方病平衡点全局渐近稳定的充分条件. 相似文献
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研究了狀种群非自治Volterra Lotka竞争模型,这个模型中参数是与时间相关的,并且分别渐近接近于周期函数的,在某些条件下,证明了此模型的任意一个正解渐近接近于相应周期系统的唯一的严格正周期解 相似文献
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研究了一类多因素HIV模型.建立了一个标准型的DI模型,证明了无病平衡点的局部渐近稳定性和全局渐近稳定性. 相似文献
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研究了算子子空间的渐近自反性问题,渐近自反子空间的遗传斯近自反性以及某些单个算子的渐近自反性.我们也讨论了投影网类的浙近自反性。 相似文献
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考虑部分线性模型Y=X‘β+g(T)+e,x∈D,t∈「0,1」,β为未知的参数向量,g为未知函数,Chen给出此模型的一种估计如下,先用分段多项式逼近g,然后用最小二乘法估计β,「1」得到估计量β的渐近正态性。因其渐近分布中含有未知参数,不能直接用于检验问题。 相似文献
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C.B. Corcino 《数学研究及应用》2001,21(4):513-524
本文利用组合分析中的循环指示表示方法,找到了Sheffer型多项式的渐近展开公式及余项估计,文末讨论了所得渐近公式的运用范围, 相似文献
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周期系数三种群Lotka-Volterra混合模型分析 总被引:3,自引:0,他引:3
考虑三种群Lotka-Volterra周期系数模型,种群间既有捕食关系又有竞争关系,得到唯一存在全局渐近稳定周期解的条件,并举例说明条件的可行性. 相似文献
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引入了Hilbert空间中一类新的渐近几乎非扩张曲线,并讨论了这类新的渐近几乎非扩张曲线的渐近行为与遍历性,进一步,作为应用,得到了Hilbert空间中非Lipschitz映象的非线性算子族的渐近行为与遍历性方面的结果。 相似文献
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Here we study the problems of local asymptotic normality of the parametric family of distributions and asymptotic minimax efficient estimators when the observations are subject to right censoring. Local asymptotic normality will be established under some mild regularity conditions. A lower bound for local asymptotic minimax risk is given with respect to a bowl-shaped loss function, and furthermore a necessary and sufficient condition is given in order to achieve this lower bound. Finally, we show that this lower bound can be attained by the maximum likelihood estimator in the censored case and hence it is local asymptotic minimax efficient. 相似文献
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The authors construct a metric space whose transfinite asymptotic dimension and complementary-finite asymptotic dimension are both 2ω + 1, where ω is the smallest infinite ordinal number. Therefore, an example of a metric space with asymptotic property C is obtained. 相似文献
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The authors define a notion of system of sets with multiplicative asymptotic density in this paper. A criterion and one necessary
condition for a given system {A
i
}
i=1∞ to be a system with multiplicative asymptotic density is given. Properties of certain special types of systems of sets with
multiplicative asymptotic density are treated.
This work is supported by The Ministry of Education, Youth and Sports of the Czech Republic. Project CQR 1M06047. 相似文献
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利用Lyapunov的方法讨论了时滞微分方程x.(t)=f(t,x(t),x(t-τ(t)))的全局指数渐近稳定性和全局渐近稳定性. 相似文献
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We introduce the estimating function with asymptotic bias and investigate the asymptotic behavior of the estimator based on it by using their relationship. The estimator based on the estimating function with asymptotic bias has the asymptotic normality with asymptotic bias. We show that this theory has several interesting applications in practical statistics. 相似文献
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设h≥2,若h阶渐近基A的任一真子集均不是h阶渐近基,则称集合A是自然数集N的h阶极小渐近基.为进一步刻画渐近基与极小渐近基之间的关系,本文综合运用自然数的b进制表示理论及分类讨论的方法,证明了存在一个集合是4阶渐近基且其任何子集均不是4阶极小渐近基. 相似文献
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Asymptotic distribution of the weighted least squares estimator 总被引:3,自引:0,他引:3
Jun Shao 《Annals of the Institute of Statistical Mathematics》1989,41(2):365-382
This paper derives the asymptotic distribution of the weighted least squares estimator (WLSE) in a heteroscedastic linear regression model. A consistent estimator of the asymptotic covariance matrix of the WLSE is also obtained. The results are obtained under weak conditions on the design matrix and some moment conditions on the error distributions. It is shown that most of the error distributions encountered in practice satisfy these moment conditions. Some examples of the asymptotic covariance matrices are also given. 相似文献