京都駅前セミナー

〜非線形現象の数理を考える〜

 

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◎第66回

日時: 平成27年 11月6日(金) 14時00分〜17時30分
場所:キャンパスプラザ京都 6階第7講習室

講演1

Jann-Long Chern National Central University, Taiwan

時間

14:00〜15:30

題目

(1)  On the Elliptic Equations of Hardy-Sobolev Type with Multiple Boundary Singularities

(2)On the Multivortex Solutions of Maxwell-Chern-Simons Model

概要

(1)In this talk, we are interested in how the geometry of boundary singularities 
can affect the attainability of the respective best Caffarelli-Kohn-Nirenberg and
Hardy-Sobolev constant. 
(2)Regarding the self-dual equations of the Maxwell-Chern-Simons model, we study
several aspects of different types of solutions of a general elliptic system on  R2.
We establishes the following: 

(a)Uniqueness of radially symmetric topological solutions.

(b) Structure of all radially symmetric solutions.

(c)An energy result that classifies non-topological solutions with a single vortex.

(d)Uniqueness for multi-vortex, topological solutions for a range of parameters.

 

講演2

Bae Soohyun Hanbat National University, Korea

時間

16:00〜17:30

題目

Asymptotic self-similarity of positive radial solutions for quasilinear equations of

Lane-Emden type

概要

Asymptotic self-similarity is a basic tool to study positive entire solutions in

Lane-Emden equations. In this talk, we explain the asymptotic self-similarity for

quasilinear equations of Lane-Emden type. One of related papers is "A generalized

Pohozaev identity and its applications" by Kawano, Ni and Yotsutani in 1990.

 

◎第65回

日時: 平成27年 5月8日(金) 14時00分〜17時30分
場所:キャンパスプラザ京都 6階第7講習室

講演1

Marko Jusup九州大学大学院理学研究院

時間

14:00〜15:30

題目

Integrating ontogeny, population dynamics, and social dilemmas into a mathematical framework for bioresource management

概要

Population dynamics is at the heart of almost every scientifically-based attempt to manage bioresources. Because of the complexity of the phenomena at the population level, such attempts rely on extremely simplifying assumptions regarding the ontogenetic development or the socio-economic interactions. For example, ontogeny is often represented by fitting length-at-age or fecundity-at-age curves to the data, resulting in statistical relationships that completely ignore the changing environment. Also, harvesting policies are commonly prescribed in terms of sustainable yields obtained from the population models, thus ignoring the self-interest of harvesters who pursue maximum short-term profits. By contrast, we focus on showing how the elements of physiological energetics, population dynamics, and game theory combine together into an integrative mathematical framework for bioresource management with which the problems beyond those arising from the population-level phenomena can be tackled. Having the framework in place, we discuss why more sophisticated models, rather than having better predictive power, actually highlight the gaps in knowledge that (should) lead to more nimble and, therefore, robust management strategies.

 

講演2

Catherine Beauchemin Ryerson University

時間

16:00〜17:30

題目

Learning mathematical lessons from influenza infections:Reality is a tough teacher!

概要

In this presentation, I will discuss some of the interesting things we learned about mathematical modelling and the assumptions we make when creating models of virus infections. I will also discuss a series of modelling improvements we have considered over the years, including the addition of realistic delays for the time spent by a cell in a particular state, the consideration of cell co-infection by defective interfering virus, and the impact of the spatial environment of the infection on its spread through the respiratory tract and on its severity.

 

◎第64回

日時: 平成27年 4月24日(金) 14時00分〜17時30分
場所:キャンパスプラザ京都 6階第7講習室

講演1

Petr Pauš(明治大学)

時間

14:00〜15:30

題目

Parametric mean curvature flow for open curves and its application

概要

The talk focuses on the parametric description of evolving open curves with fixed or free end points. The curves are driven by the normal velocity. We will present suitable mathematical model, its numerical description, and computer simulation results. We will also show that the motion preserves convexity of the curve similarly to the mean curvature flow of closed curves. The curve pinching will also be dealt. The numerical model for open curves is then applied in the field of discrete dislocation dynamics and Beloushov-Zhabotinsky reaction. Mainly the spiral motion is dealt. The presented model also incorporates the redistribution of the discretization points and an improved algorithm for topological changes of the curves (i.e., splitting and merging of the curves).

 

講演2

秋山 正和 北海道大学電子科学研究所

時間

16:00〜17:30

題目

平面内細胞極性の数理モデルと解の安定性について

概要

髪の毛や眉毛の「毛の流れ」がどのように決まっているか考えたことがあるだろうか?
哺乳類の毛だけなく,魚類の鱗,鳥類の羽毛などの毛の流れ方は「平面内細胞極性」とよばれるメカニズムが機能することによって制御されていることが知られている.平面内細胞極性は分子生物学の発展によりショウジョウバエの翅において特に研究が進んでおり,詳細な分子メカニズムもわかりつつある.
我々はこの分子の働きに着目して,非常に簡単な4変数モデルを構築し,現象の解明を試みた.(Dachsous-Dependent Asymmetric Localization of Spiny-Legs Determines  Planar Cell Polarity Orientation in Drosophila. Cell Reports, 8(2): p.610 - 621
さらに数理的な解析により,この4変数モデルは更に簡単な1変数モデルへと帰着できることがわかった.
講演では平面内細胞極性に関してさらに詳しく紹介し,4変数モデルの導出方法,1変数モデルの解とその安定性に関して発表したい