|創校85週年暨創系60週年系列演講, 台灣大學大氣科學系 郭鴻基 教授|
Thursday, October 6, 16:10—17:00 數學系3174教室
Title: Record-Breaking Increase in Taiwan Typhoon Rainfall in the 21st Century
Abstract: Since the beginning of the 21st century Taiwan has experienced a dramatic increase in typhoon-related rainfall. Some investigators suggested that they are the manifestation of global warming effects. However, an analysis of typhoon rainfall intensity with respect to typhoon tracks in different landfall phases relative to the Central Mountain Range indicates this is unlikely the cause. Rather, most of the recently observed large increase in typhoon rainfall in the pre-landing and overland phases is the result of slower moving tropical cyclones (TCs) and their tracks relative to the high mountains. A positive feedback mechanism in which the convective heating pattern forced by topography acts to slow down the TC motion, which is most efficient for the slower-moving northern-track storms. Another factor contributing to increased TC-related rainfall is the interaction between the typhoon circulation and southwest monsoon. When the data analyzed ends in 2011, this factor is most important after the typhoon center exits Taiwan and led to the increase of both typhoon rainfall intensity and rainfall amount in the new century. When the data coverage is extended to 2014, the effects become even more prominent as the increasing rainfall due to monsoon is evident when the typhoon center is still over land. Both the slower TC motion and the increased monsoon induced rainfall are consistent with the recently observed multidecadal trend of intensifying subtropical monsoon and tropical circulations, which is contrary to some theoretical and model projections of global warming.
|創校85週年暨創系60週年系列演講, 台灣大學數學系 陳榮凱 教授|
Wednesday, October 12, 15:10—16:00 數學系3174教室
Title: Birational Geometry and Birational Classification of Algebraic Threefolds
Abstract: Algebraic varieties are the main objects in the studies of algebraic geometry. It is thus natural to classify varieties into birational equivalence classes and to study the geometry in each equivalence classes. These leads to two challenges: birational classification theory and minimal model theory, which is the main tool in the study of birational geometry inside an equivalence class.
In this talk, I will give a brief introduction to the theory of threefolds, including birational classification theory and theory of birational geometry. I will also provide some recent updates and introduce some open problems.
|創校85週年暨創系60週年系列演講, 中央研究院數學研究所 劉太平 院士|
Thursday, October 13, 16:10—17:00 三系館成功共同教室 A1302
Title: Truth and Beauty
Abstract: Science is about truth and art is about beauty. As we have seen in many instances, truth and beauty are deeply related. In this talk we start with the example of Boltzmann the scientist and Chu Yuan the ancient poet from the East. There is similarity between these two towering figures in their absolutism; but it is their pursuit of beauty and truth that define their greatness. There are key issues handed to us from these giants that continue to concern us. The reversibility/irreversibility of physical phenomena is such an issue that has continued to puzzle leading thinkers since the time of the great mathematician Poincare. We will discuss recent ideas on this as well as other cultural issues.
|創校85週年暨創系60週年系列演講, 台灣大學數學系 王振男 教授|
Wednesday, October 19, 16:10—17:00 數學系3174教室
Title: Second Order Elliptic Equations with Complex Coefficients: Quantitative Uniqueness Estimates, Variational Structure, and Size Estimate
Abstract: Second order elliptic equations with complex coefficients arise from some well-known physical models such as the electromagnetic waves propagating in a conductive medium. In this talk, I would like to discuss several topics about this type of equations. I will first talk about the unique continuation property for solutions of the complex second order elliptic equation. With the application to the size estimate problem in mind, the aim is to derive some quantitative uniqueness estimates of solutions. Unlike the real second order elliptic equation, to study the size estimate problem, we have to investigate the variational structure of the equation in a real-valued formulation.
|創校85週年暨創系60週年系列演講, 交通大學應用數學所 賴明治 教授|
Thursday, October 27, 16:10—17:00 數學系3174教室
Title: Numerical Issues on Some Interfacial Problems with Fluid Flow
Abstract: In this talk, we shall introduce some numerical issues arising from 3D simulations for the interfacial flows with surfactant and vesicle problems. In particular, the major numerical challenges to study those problems mainly fall into the geometrical modeling of 3D surface representations and its computations on geometrical quantities and the derivatives along the surface. We will explain the mathematical models and the numerical methods in detail.
|PDE Seminar, 香港科技大學 Yi-Hsuan Lin 博士|
Thursday, October 31, 14:10—15:00 數學系3F會議室
Title: Special Solutions related to Inverse Problems
Abstract: The area of inverse problems consist many different interesting problems. In this talk, we will introduce how to find the information of the unknown obstacles in an given domain and we also give an algorithm to reconstruct the coefficients for some partial differential equations. More specifically, we will demonstrate the ideas and methods by using the isotropic elasticity equation as an example.