学术报告
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Lyapunov Functional for Delay Epidemiological Models and Population DynamicsThe Lyapunov functionals are very useful for the analysis of the global asymptotic behavior of the delay differential equations models. In this talk, we present several delay epidemiological models, in which time delays appear in different position of models and describe different biological meanings. Several Lyapunov functionals were applied to delay models above. And we develop further the Lyapunov functional to more delay differential equations in population dynamics.黄刚致远楼110室2017年11月3日(星期五)15:00-15:50
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Modelling Diapause in Mosquito GrowthDiapause (or named as dormancy traditionally) as a process of physiological rest is widespread in insects and other invertebrate organisms, which serves as a key survival mechanism in response to adverse environmental conditions. In this paper, a novel modelling framework is proposed to investigate the effects of diapause on population growth, where diapause period is taken as an independent dynamic process, during which the population dynamics is completely different from that in the normal developmental and post-diapause periods. To explicitly describe population growth with different diapausing stages, either immature or adult ones, two different delay differential equation models are constructed with an emphasis on mosquitoes.楼一均宁静楼110室2017年11月3日(星期五)16:00-16:50
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The Dual Log-Brunn-Minkowski InequalityIn this talk, we will prove the dual log-Brunn-Minkowski inequality and the dual log-Minkowski inequality. Moreover, the equivalence between the dual log-Brunn-Minkowski inequality and the dual log-Minkowski inequality is demonstrated.汪卫 副教授瑞安楼 205 教室2017年11月02日 14:00-15:00
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On the Changing of the Dimension of a Basic Set by Means of Simple Bifurcatio...One of the fifty problems of dynamical systems formulated by J. Palis and C. Pugh is the problem of the existence of a simple arc joining two structural stable systems on a smooth closed manifold [1]. Simplicity means that the arc consists of structural stable systems with the exception of a finite set of points where the system has the least deviation from a rough system, that is simple bifurcations: a saddle-node, a doubling period or a bifurcation of a heteroclinic tangency. We show that by means of such arc it is possible to change the dimension of a basic set. Namely we joint arbitrary structural stable 3-diffeomorphism with an expanding two-dimensional attractor with an Anosov diffeomorphism.Olga Pochinka 教授宁静楼110室11月1日(星期三),下午 3:30-4:30
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The Compressible Euler equations with Gravity: Well-balanced Schemes and All ...We consider astrophysical systems that are modeled by the multidimensional Euler equations with gravity. First for the homogeneous Euler equations we look at flow in the low Mach number regime. Here for conventional finite volume discretization one has excessive dissipation in this regime. We identify inconsistent scaling for low Mach numbers of the numerical flux function as the origin of this problem. Based on the Roe solver a technique that allows to correctly represent low Mach number flows with a discretization of the compressible Euler equations is proposed. We analyze properties of this scheme and demonstrate that its limit yields a discretization of the incompressible limit system.Christian Klingenberg宁静楼104 室2017/10/27 (星期五) 11:00~12:00
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Epidemic Model with Multiple Delays: Impact of Cofeeding and DiapauseWe consider the dynamic vector-host-pathogen interaction motivated by such tick borne diseases as tick-borne encephalitis and Lyme disease. We stratify the vector population in terms of the stage before and after the contact with the host when co-feeding transmission may take place, and we consider the case where vector development may involve two time lags due to diapause. We derive and calculate the critical rate for the model to exhibit nonlinear oscillations.吴孝钿 副教授宁静楼110室10月20日(星期五),下午 2:30-3:30
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Effect of Travel Frequency on the Spatial Spread of Infectious DiseasesAs we know, there are differences in travel frequency among people by age, ethnicity, region, gender, income, etc. Usually only a small fraction of people are frequent travelers while most travel occasionally or never. For instance, the percentages of frequent air traveler, occasional air traveler, and never flown in the U.S. in 2015 are 7%, 71%, and 22%, respectively. In this talk, we propose a multipatch epidemic model to investigate the effect of travel behavior on the spread of infectious diseases.高道舟 教授宁静楼110室10月20日(星期五),下午 3:30-4:30
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On the Critical One Component Regularity for 3-D Navier-Stokes System在本次报告中,我们将首先回顾经典Navier-Stokes方程的正则性结果,而后介绍我们在3维各向异性的navier-Stokes方程方面的适定性结果;最后介绍我们最近有关3维经典Navier-Stokes方程的一个分量的临界正则性准则。张平 研究员宁静楼108室2017年10月13日(周五)下午3:30到4:30