一类具有非线性发生率的SIS传染病模型的定性分析

应用微分方程定性理论,研究了一类具有非线性发生率的SIS传染病模型.给出了该系统极限环的存在性、唯一性以及无病平衡点和地方病平衡点的全局渐近稳定性的充分条件.

Abstract：

An epidemiological model with nonlinear incidence is studied. By using the qualitative theory of ordinary differential equations, sufficient conditions are obtained for the existence and uniqueness of the limit cycles and the global asymptotic stability of the disease-free equilibrium and the endemic equilibrium to the system.     

一类具有常数输入率的有差异的两子群间的SIRS模型

建立并分析了一类总人口变动的包含具有差异性两子群的单种群的SIRS传染病模型.当基本再生率R_0≤1时,系统仅存在无病平衡点,且它是全局渐近稳定的.当R_0 >1时,存在唯一的地方病平衡点,并且它存在即局部渐近稳定.通过Lyapunov函数法建立了地方病平衡点全局渐近稳定的充分条件.

Abstract：

An SIRS epidemiological model for a single species population with varying size and two discrepant sub-groups is formulated and analyzed.If the basic reproduction rate R_0≤ 1, only the disease-free equilibrium exists, which proves to be globally asymptotically stable.There exists a unique endemic equilibrium if R_0 > 1 and it is local-ly asymptotically stable whenever it exists.Sufficient conditions are obtained for global asymptotic stability of the endemic equilibrium via the method of Lyapunov functions.     

具有两种免疫来源的乙肝病毒模型的全局动力学

研究了免疫反应具有两种来源的乙肝病毒模型.通过对相应特征方程的分析,讨论了感染平衡态和未感染平衡态的局部稳定性,证明了基本再生数>1时疾病的持续性.通过几何方法的应用,得到了感染平衡点全局稳定性的充分条件.

Abstract：

In this paper,an HBV model with activated immune response of two sources is studied.By analyzing the corresponding characteristic equations,the local stability of an infected steady state and an uninfected steady state is discussed.It is proved that if the basic reproductive number is more than one,the disease is persistent.By applying a geometric method,sufficient conditions are obtained for the global stability of the endemic equilibrium.     

一类新的极值估计量

提出了一类新的极值指数估计量,证明了该估计量的相合性以及渐近性.

Abstract：

In this paper, a new class of estimator for the extreme value index is proposed, and the consistency and asymptotic property of this estimator are proved.     

具有竞争的Leslie型捕食者-食饵模型的定性分析

考虑了具有竞争的Leslie型模型.证明了解的最终有界性,和系统在一定条件下的一致持续生存性.研究了平衡点的局部稳定性.通过构建适当的Lyapunov函数,获得了正平衡点全局渐进稳定的充分条件.

Abstract：

In this paper, a competitive Leslie model is proposed. It is proved that the system's solution is ultimately bounded and the system is consistent and sustained under appropriate conditions. The local stability of the equilibria is investigated. By constructing a suitable Lyapunov functional, sufficient conditions are derived for the global stability of the positive equilibrium of the model.     

ROBUST REPETITIVE CONTROL FOR IMPROVING RATE SMOOTHNESS OF TEST TURNTABLE

A robust repetitive control scheme is used to improve the rate smoothness of a brushless DC motor (BLDCM) driven test turntable. The method synthesizes variable structure control (VSC) laws and repetitive control (RC) laws in a complementary manner. The VSC strategy can stabilize the system and suppress uncertainties, such as the aperiodic disturbance and noises, while RC strategy can eliminate the periodic rate fluctuation in a steady state. The convergence of the repetitive learning process is also guaranteed by VSC. A general nonlinear system model is discussed. The model can be considered as an extension of BLDCMs. The stability and asymptotic position tracking performance are validated by using Lyapunov functions. Simulation results show the effectiveness of the proposed approach for improving the rate smoothness.     

一类二阶非线性摄动微分不等式的渐近性质

研究了一类二阶非线性摄动微分不等式非振动解的渐近性质,在一定条件下,建立了3个新的渐近性定理,推广和改进了已知的结果.

Abstract：

In this paper, we present some criteria for the asymptotic property of a class of second order nonlinear differential inequality with perturbation and, under certain conditions construct 3 new asymptotic behavior theorems. The results generalize and reform the known results.     

重庆市机动车排放因子研究

介绍了计算机动车污染物排放因子的MOBILE5模型,并根据重庆市机动车实际构成、行驶工况、I/M制度等数据确定了模型所需参数,然后应用该模型计算得到1985,1990,1995,2000和2004年重庆机动车排放CO、NOx和HC的排放因子.通过比较MOBILE5模式和台架测试得到的重庆机动车排放因子发现,应用MOBILE5模型计算获得的排放因子偏低于实际情况.

Abstract：

The MOBILE5 model for calculating the emission factors of motor vehicles is described and the required parameters are determined based on the actual categories, driving cycles, the rule of I/M and anyother parameters of motor vehicles in Chongqing. Then the model is used to calculate the vehicle emis-sion factors of CO, NOX and HC in Chongqing in 1985, 1990, 1995, 2000 and 2004. By comparing the differences between the emission factors derived from the MOBILE5 model and the chassis dynamometer,it is found that the emission factors calculated with the MOBILE5 model is smaller than the actual emission status in Chongqing.     

类具有急慢性阶段和垂直传染的非线性SACS传染病模型

研究一类具有非线性接触率和垂直传染且在急慢性阶段均传染的非线性SACS传染病侍播数学模型动力学性质,确定了各类平衡点存在的条件阈值,讨论了各平衡点的稳定性,并将会在临界值处出现Hopf分支,揭示了急慢性阶段传染对疾病发展趋势的共同影响.

Abstract：

The dynamics of a nonlinear SACS epidemic model with vertical transmission, which has infective force at both acute and chronic stages, is studied. The conditions and thresholds for the existence of various equilibria are established. The stability of equilibria is discussed, and periodic solutions may appear by Hopf bifurcation. The influence of infectivity at acute and chronic stages on the developing trend of the disease is disclosed.