Efficient estimation of varying coefficient seemly unrelated regression model

In this paper, we propose a class of varying coefficient seemingly unrelated regression models, in which the errors are correlated across the equations. By applying the series approximation and taking the contemporaneous correlations into account, we propose an efficient generalized least squares series estimation for the unknown coefficient functions. The consistency and asymptotic normality of the resulting estimators are established. In comparison with the ordinary/east squares ones, the proposed estimators are more efficient with smaller asymptotical variances. Some simulgtlon＇studies and a real application are presented to demonstrate the finite sample performance of the proposed methods. In addition, based on a B-spline approximation, we deduce the asymptotic bias and variance of the proposed estimators.     

Asymptotic stability for one-dimensional motion of non-Newtonian compressible fluids

Rarefaction wave solutions for a one-dimensional model system associated with nomNewtonian compressible fluid are investigated in terms of asymptotic stability. The rarefaction wave solution is proved to be asymptotically stable, provided the initial disturbance is suitably small. The proof is given by the elemental L2 energy method.     

GLOBAL EXISTENCE AND ASYMPTOTIC BEHAVIOR FOR THE 3D COMPRESSIBLE NON–ISENTROPIC EULER EQUATIONS WITH DAMPING

We investigate the global existence and asymptotic behavior of classical solutions for the 3D compressible non-isentropic damped Euler equations on a periodic domain. The global existence and uniqueness of classical solutions are obtained when the initial data is near an equilibrium. Furthermore, the exponential convergence rates of the pressure and velocity are also proved by delicate energy methods.     

COMBINED EFFECTS IN A SEMILINEAR POLYHARMONIC PROBLEM IN THE UNIT BALL

Let m be a positive integer and B be the unit ball of Rn(n ≥ 2). We investigate the existence, uniqueness and the asymptotic behavior of a positive continuous solution to the following semilinear polyharmonic boundary value problem(-△)mu = a1(x)uα1+ a2(x)uα2, lim|x|→1u(x)(1- |x|)m-1= 0,where α1, α2 ∈(-1, 1) and a1, a2 are two nonnegative measurable functions on B satisfying some appropriate assumptions related to Karamata regular variation theory.     

ON GLOBAL STABILITY OF A NONRESIDENT COMPUTER VIRUS MODEL

In this paper, we establish new sufficient conditions for the infected equilibrium of a nonresident computer virus model to be globally asymptotically stable. Our results extend two kind of known results in recent literature.     

随机自治系统的Lasalle定理的改进

稳定性问题是研究各类动态系统的最基本也是最重要的问题之一.稳定性理论已经积累了十分丰富的成果,将Lasalle定理应用到随机微分自治系统中构造具体的Lyapunov函数,得到随机自治系统渐近稳定的有用判据.最后具体实例来说明改进结果的有效性.     

周期演化域上一个禽流感模型的动力学分析

本文研究了周期演化区域上一个禽流感模型.首先假设区域的增长为各向同性,将模型转换为固定区域上的反应扩散问题.然后利用相关的特征值问题和上下解方法得出模型解的渐近性态.研究结果表明,周期性区域的演化对疾病的传播与抑制取决于区域的周期演化速率ρ(t)的积分平均值ρ-2=1/T∫0T1/ρ2(t)dt.若ρ-2>1,则周期性区域的演化可抑制疾病的传播;若ρ-2<1,则周期性区域的演化可加速疾病的传播;若ρ-2=1,则周期性区域的演化对疾病的传播没有影响.     

关于Landau常数和Euler-Mascheroni常数的渐近展开式以及Stirling级数的系数

文章给出一个递推关系式来确定Landau常数的渐近展开式的系数.考虑了Euler-Mascheroni常数和n!的渐近展开式,并给出了递推关系式来确定每个展开式的系数,没有利用Bernoulli数.     

随机删失单函数型指标模型条件众数估计的渐近正态性

基于单函数型指标模型,构造了该模型下条件密度和条件众数的估计量,研究了 α-混合函数型数据在响应变量随机删失的情况下的条件密度和条件众数估计量的渐近正态分布,用模拟研究说明单函数型指标模型条件众数估计的有效性.