两类出生带有密度制约的不育控制下的害鼠模型

建立了两类出生带有密度制约的不育控制下的害鼠模型,利用Hurwitz判据,证明了平衡点的局部渐近稳定性,对全局稳定性进行了数值模拟,讨论了主要参数对种群动态变化的影响.     

一类带有不育控制的离散单种群模型

建立一类不育控制下的害鼠种群的离散模型.首先利用三个Jury条件,得到平衡点的局部渐近稳定性的充分条件.其次利用李雅普诺夫函数和细致分析法分别给出了零平衡点全局稳定及持续生存的充分条件.最后给出了平衡点全局稳定的数值模拟.     

带Poisson跳非线性随机种群动力学模型的最优收获控制

研究了一类带跳的非线性随机群体动力学模型的最优收获控制.给出了在外界环境对系统产生影响的条件下带有Poisson跳的随机种群动力学系统;通过随机极大值原理,Hamilton函数及Ito公式,讨论了最优收获控制所满足的充分必要条件,所得到的结论是确定性种群系统的扩展.     

一类非线性随机种群系统最优生育率控制

研究了一类非线性随机种群系统动力学模型的最优生育率控制问题.在加入外部随机因素扰动下,系统模型将会更具有实际意义.针对随机种群系统生育率控制问题,应用It?o公式,相应的伴随方程和变分不等式等经典理论,获得了随机种群系统最优生育率控制所满足的必要条件及其最优性组(由积分-偏微分方程和变分不等式组成).文中得到的结论是确定性种群系统的扩展,对随机控制理论具有现实的应用价值.     

具两系统切换的脉冲阶段结构单种群动力学模型研究

建立具两系统切换脉冲阶段结构单种群动力学模型,利用离散动力系统频闪映射理论,得到系统种群灭绝与系统种群持续生存的控制阈值.结果表明脉冲收获与冬眠期对于系统种群持久起着重要作用,从而为现实的生物资源管理与生物多样性保护提供了可靠的策略依据.     

具阶段结构害虫防治模型的脉冲效应

对于用微分方程描述的种群生态动力系统，其研究结果已十分丰富，但自然界中的许多变化规律都呈现出脉冲效应，因此用脉冲微分方程描述某些运动状态在固定或不固定时刻的快速变化或跳跃更切合实际，尤其在刻画种群生长和流行病动力学行为方面，脉冲微分方程的描述显得更科学更真实，具有脉冲效应的种群动力学模型的研究目前还处于刚刚起步阶段，本对符合实际的有脉冲效应的具阶段结构的常系数害早防治模型进行了研究，得到了系统存在周期解的充分条件，系统存在唯一周期解的充分条件，系统周期解轨道渐近稳定的充分条件。     

一类非线性随机种群动力学模型的最优收获控制

研究了一类非线性随机种群动力学模型的最优收获控制问题,得出了在外界环境对系统产生影响的条件下,最优控制所满足的必要条件及其最优性组,所得到的结论是确定性种群系统的扩展.     

污染喀斯特环境下具瞬时与非瞬时脉冲效应的单种群动力学模型

建立污染喀斯特环境下具瞬时与非瞬时脉冲效应的单种群动力学模型.利用脉冲微分方程理论,得到系统种群持续生存的控制阈值.研究结果表明瞬时脉冲收获量与非瞬时脉冲收获区间长度对于系统种群持久起着重要作用,结论为现实的生物资源管理提供了可靠的策略支持.     

毒素脉冲输入与种群脉冲出生切换阶段结构单种群动力学模型研究

本文研究了毒素脉冲输入与脉冲出生切换阶段结构单种群动力学模型.利用常微分方程及差分分析,获得了系统种群灭绝和持久生存的控制条件结果,为污染环境中的生物资源管理提供了可靠的管理策略.     

时间测度上一些种群动力学方程的周期解

在时间测度上研究一些具有时滞的种群动力学系统,利用Mawhin重合度理论建立了这一类抽象型系统的正周期解存在的充分性条件,从而使这些种群动力学模型的连续和离散时间情形,即微分方程和差分方程得到了统一研究.将所得到的结论可以应用到很多具体的生物数学模型上.     

RECENT PROGRESS ON SPHERICAL HARMONIC APPROXIMATION MADE BY BNU RESEARCH GROUP ——In memory of Professor Sun Yongsheng

As early as in 1990, Professor Sun Yongsheng, suggested his students at Beijing Normal University to consider research problems on the unit sphere. Under his guidance and encouragement his students started the research on spherical harmonic analysis and approximation. In this paper, we incompletely introduce the main achievements in this area obtained by our group and relative researchers during recent 5 years （2001-2005）. The main topics are： convergence of Cesaro summability, a.e. and strong summability of Fourier-Laplace series; smoothness and K-functionals; Kolmogorov and linear widths.     

On a class of self-similar processes with stationary increments in higher order Wiener chaoses

We study a class of self-similar processes with stationary increments belonging to higher order Wiener chaoses which are similar to Hermite processes. We obtain an almost sure wavelet-like expansion of these processes. This allows us to compute the pointwise and local Hölder regularity of sample paths and to analyse their behaviour at infinity. We also provide some results on the Hausdorff dimension of the range and graphs of multidimensional anisotropic self-similar processes with stationary increments defined by multiple Wiener–Itô integrals.     

A REPRESENTATION FORMULA RELATED TO SCHR(O)DINGER OPERATORS

Schr(o)dinger operator is a central subject in the mathematical study of quantum mechanics.Consider the Schrodinger operator H = -△ V on R, where △ = d2/dx2 and the potential function V is real valued. In Fourier analysis, it is well-known that a square integrable function admits an expansion with exponentials as eigenfunctions of -△. A natural conjecture is that an L2 function admits a similar expansion in terms of "eigenfunctions" of H, a perturbation of the Laplacian (see [7], Ch. Ⅺ and the notes), under certain condition on V.     

On a class of Riemann surfaces

It is considered the class of Riemann surfaces with dimT1 = 0, where T1 is a subclass of exact harmonic forms which is one of the factors in the orthogonal decomposition of the spaceΩH of harmonic forms of the surface, namely The surfaces in the class OHD and the class of planar surfaces satisfy dimT1 = 0. A.Pfluger posed the question whether there might exist other surfaces outside those two classes. Here it is shown that in the case of finite genus g, we should look for a surface S with dimT1 = 0 among the surfaces of the form Sg\K , where Sg is a closed surface of genus g and K a compact set of positive harmonic measure with perfect components and very irregular boundary.     

Boundedness for commutators of multipliers on Hardy type spaces

In this paper, we study the commutators generalized by multipliers and a BMO function. Under some assumptions, we establish its boundedness properties from certain atomic Hardy space Hb^p（R^n） into the Lebesgue space L^p with p 〈 1.     

A unified approach to certain problems of best local approximation

In this paper we study best local quasi-rational approximation and best local approximation from finite dimensional subspaces of vectorial functions of several variables. Our approach extends and unifies several problems concerning best local multi-point approximation in different norms.     

THE 8~(th) INTERNATIONAL CONGRESS ON INDUSTRIAL AND APPLIED MATHEMATICS

<正>August 10-14,2015Beijing,ChinaThe International Congress on Industrial and Applied Mathematics(ICIAM)is the premier international congress in the field of applied mathematics held every four years under the auspices of the International Council for Industrial and Applied Mathematics.From August 10 to 14,2015,mathematicians,scientists