Difference between revisions of "SIAM Student Chapter Seminar"

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*'''When:''' TBA
 
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*'''Where:''' Zoom
*'''When:''' Most Friday at 11:30 am (see e-mail)
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*'''Organizers:''' [http://www.math.wisc.edu/~xshen/ Xiao Shen]
*'''Where:''' 901 Van Vleck Hall
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*'''Faculty advisers:''' [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault], [http://pages.cs.wisc.edu/~swright/ Steve Wright]  
*'''Organizers:''' [http://www.math.wisc.edu/~xshen/ Xiao Shen]  
 
 
*'''To join the SIAM Chapter mailing list:''' email [join-siam-chapter@lists.wisc.edu].
 
*'''To join the SIAM Chapter mailing list:''' email [join-siam-chapter@lists.wisc.edu].
  
 
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== Fall 2020 ==
== Fall 2019 ==
 
  
 
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!align="left" | title
 
!align="left" | title
 
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|Sept. 27, Oct. 4
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|TBA
|[http://www.math.wisc.edu/~xshen/ Xiao Shen] (Math)
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|Yu Feng (Math)
|''[[#Sep 27, Oct 4: Xiao Shen (Math)|The corner growth model]]''
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|''[[#TBA, Yu Feng (Math)|Phase separation in the advective Cahn--Hilliard equation]]''
 
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|Oct. 11
 
|''no seminar''
 
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|Oct. 18
 
|[https://scholar.google.com/citations?user=7cVl9IkAAAAJ&hl=en Bhumesh Kumar] (EE)
 
|''[[#Oct 18: Bhumesh Kumar (EE)|Non-stationary Stochastic Approximation]]''
 
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|Oct. 25
 
|Max Bacharach
 
|''[[#Oct 25:|Coalescent with Recombination]]''
 
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|Nov. 1
 
|''no seminar''
 
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|Nov. 8
 
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== Abstract ==
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== Abstracts ==
  
=== Sep 27, Oct 4: Xiao Shen (Math) ===
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=== TBA, Yu Feng (Math) ===
'''The corner growth model'''
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'''Phase separation in the advective Cahn--Hilliard equation'''
  
Imagine there is an arbitrary amount of donuts attached to the integer points of Z^2. The goal is to pick an optimal up-right path which allows you to eat as much donuts as possible along the way. We will look at some basic combinatorial observations, and how specific probability distribution would help us to study this model.
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The Cahn--Hilliard equation is a classic model of phase separation in binary mixtures that exhibits spontaneous coarsening of the phases. We study the Cahn--Hilliard equation with an imposed advection term in order to model the stirring and eventual mixing of the phases. The main result is that if the imposed advection is sufficiently mixing then no phase separation occurs, and the solution instead converges exponentially to a homogeneous mixed state. The mixing effectiveness of the imposed drift is quantified in terms of the dissipation time of the associated advection-hyperdiffusion equation, and we produce examples of velocity fields with a small dissipation time. We also study the relationship between this quantity and the dissipation time of the standard advection-diffusion equation.
  
  
=== Oct 18: Bhumesh Kumar (EE) ===
 
'''Non-stationary Stochastic Approximation'''
 
  
Abstract: Robbins–Monro pioneered a general framework for stochastic approximation to find roots of a function with just noisy evaluations.With applications in optimization, signal processing and control theory there is resurged interest in time-varying aka non-stationary functions. This works addresses that premise by providing explicit, all time, non-asymptotic tracking error bounds via Alekseev's nonlinear variations of constant formula.
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<br>
  
Reference: https://arxiv.org/abs/1802.07759 (To appear in Mathematics of Control, Signals and Systems)
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== Past Semesters ==
 
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*[[SIAM_Student_Chapter_Seminar/Spring2020|Spring 2020]]
=== Oct 25: Max Bacharach (Math) ===
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*[[SIAM_Student_Chapter_Seminar/Fall2019|Fall 2019]]
'''Coalescent with Recombination'''
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*[[SIAM_Student_Chapter_Seminar/Fall2018|Fall 2018]]
 
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*[[SIAM_Student_Chapter_Seminar/Spring2017|Spring 2017]]
I will talk about the continuous time coalescent with mutation and recombination, with a focus on introducing key concepts related to genetic distance and evolutionary relatedness. The talk will be informal and accessible.
 
 
 
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Latest revision as of 00:18, 18 September 2020



Fall 2020

date speaker title
TBA Yu Feng (Math) Phase separation in the advective Cahn--Hilliard equation

Abstracts

TBA, Yu Feng (Math)

Phase separation in the advective Cahn--Hilliard equation

The Cahn--Hilliard equation is a classic model of phase separation in binary mixtures that exhibits spontaneous coarsening of the phases. We study the Cahn--Hilliard equation with an imposed advection term in order to model the stirring and eventual mixing of the phases. The main result is that if the imposed advection is sufficiently mixing then no phase separation occurs, and the solution instead converges exponentially to a homogeneous mixed state. The mixing effectiveness of the imposed drift is quantified in terms of the dissipation time of the associated advection-hyperdiffusion equation, and we produce examples of velocity fields with a small dissipation time. We also study the relationship between this quantity and the dissipation time of the standard advection-diffusion equation.



Past Semesters