https://www.math.wisc.edu/wiki/api.php?action=feedcontributions&user=Qinli&feedformat=atomUW-Math Wiki - User contributions [en]2020-12-02T01:43:18ZUser contributionsMediaWiki 1.30.1https://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/Spring2021&diff=20349Applied/ACMS/Spring20212020-11-14T21:38:20Z<p>Qinli: /* Spring 2021 */</p>
<hr />
<div>== Spring 2021 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 29<br />
|<br />
|<br />
|<br />
|-<br />
| Feb 5<br />
|[https://www.math.wisc.edu/~remondtiedre/ Antoine Remond-Tiedrez] (UW)<br />
|''[[Applied/ACMS/absS21#Antoine Remond-Tiedrez (UW)|TBA]]''<br />
|Spagnolie<br />
|-<br />
| Feb 12<br />
|[http://appliedmaths.sun.ac.za/~htouchette/ Hugo Touchette] (Stellenbosch University)<br />
|''[[Applied/ACMS/absS21#Hugo Touchette (Stellenbosch University)|TBA]]''<br />
|Jean-Luc<br />
|-<br />
| Feb 19<br />
|<br />
|<br />
|<br />
|-<br />
| Feb 26<br />
|[https://www.math.wisc.edu/~qdeng37/ Quanling Deng] (UW)<br />
|''[[Applied/ACMS/absS21#Quanling Deng (UW)|TBA]]''<br />
|Stechmann and Chen<br />
|-<br />
| Mar 5<br />
|<br />
|<br />
|<br />
|-<br />
| Mar 12<br />
|[https://www.math.umass.edu/directory/faculty/yulong-lu Yulong Lu] (University of Massachusetts)<br />
|''[[Applied/ACMS/absS21#Yulong Lu (University of Massachusetts)|TBA]]''<br />
|Li<br />
|-<br />
| Mar 19<br />
|Michelle DiBenedetto (University of Washington)<br />
|TBA<br />
|Jean-Luc<br />
|-<br />
| Mar 26<br />
|[https://drexel.edu/coas/faculty-research/faculty-directory/mondaini-cecilia/ Cecilia Mondaini] (Drexel University)<br />
|TBA<br />
|Chen<br />
|-<br />
| Apr 2<br />
|<br />
|<br />
|<br />
|-<br />
| Apr 9<br />
|<br />
|<br />
|<br />
|-<br />
| Apr 16<br />
|<br />
|<br />
|<br />
|-<br />
| Apr 23<br />
|<br />
|<br />
|<br />
|-<br />
|}</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/Spring2021&diff=20342Applied/ACMS/Spring20212020-11-14T00:29:58Z<p>Qinli: /* Spring 2021 */</p>
<hr />
<div>== Spring 2021 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 29<br />
|<br />
|<br />
|<br />
|-<br />
| Feb 5<br />
|[https://www.math.wisc.edu/~remondtiedre/ Antoine Remond-Tiedrez] (UW)<br />
|''[[Applied/ACMS/absS21#Antoine Remond-Tiedrez (UW)|TBA]]''<br />
|Spagnolie<br />
|-<br />
| Feb 12<br />
|[http://appliedmaths.sun.ac.za/~htouchette/ Hugo Touchette] (Stellenbosch University)<br />
|''[[Applied/ACMS/absS21#Hugo Touchette (Stellenbosch University)|TBA]]''<br />
|Jean-Luc<br />
|-<br />
| Feb 19<br />
|<br />
|<br />
|<br />
|-<br />
| Feb 26<br />
|[https://www.math.wisc.edu/~qdeng37/ Quanlin Deng] (UW)<br />
|''[[Applied/ACMS/absS21#Quanlin Deng (UW)|TBA]]''<br />
|Stechmann and Chen<br />
|-<br />
| Mar 5<br />
|<br />
|<br />
|<br />
|-<br />
| Mar 12<br />
|[https://www.math.umass.edu/directory/faculty/yulong-lu Yulong Lu] (University of Massachusetts)<br />
|''[[Applied/ACMS/absS21#Yulong Lu (University of Massachusetts)|TBA]]''<br />
|Li<br />
|-<br />
| Mar 19<br />
|Michelle DiBenedetto (University of Washington)<br />
|TBA<br />
|Jean-Luc<br />
|-<br />
| Mar 26<br />
|[https://drexel.edu/coas/faculty-research/faculty-directory/mondaini-cecilia/ Cecilia Mondaini] (Drexel University)<br />
|TBA<br />
|Chen<br />
|-<br />
| Apr 2<br />
|<br />
|<br />
|<br />
|-<br />
| Apr 9<br />
|<br />
|<br />
|<br />
|-<br />
| Apr 16<br />
|<br />
|<br />
|<br />
|-<br />
| Apr 23<br />
|<br />
|<br />
|<br />
|-<br />
|}</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=20198Applied/ACMS2020-10-23T18:07:51Z<p>Qinli: /* Fall 2020 */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li], [http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' Send mail to [mailto:acms+join@g-groups.wisc.edu acms+join@g-groups.wisc.edu].<br />
<br />
<br><br />
<br />
<br />
== Fall 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Sep 11<br />
|[https://cee.stanford.edu/people/nicholas-ouellette Nick Ouellette (Stanford)]<br />
|''[[Applied/ACMS/absF20#Nick Ouellette (Stanford)|Tensor Geometry in the Turbulent Cascade]]''<br />
|Jean-Luc<br />
|-<br />
| Sep 18<br />
|[https://www.researchgate.net/profile/Harry_Lee24 Harry Lee (UW-Madison and UMich)]<br />
|''[[Applied/ACMS/absF20#Harry Lee (UW-Madison, UMich)|Recent extension of V.I. Arnold's and J.L. Synge's mathematical theory of shear flows]]''<br />
|Wally<br />
|-<br />
| Sep 25<br />
|[https://www.mtholyoke.edu/people/spencer-smith Spencer Smith (Mount Holyoke)]<br />
|''[[Applied/ACMS/absF20#Spencer Smith (Mount Holyoke)|Braids on a lattice and maximally efficient mixing in active matter systems]]''<br />
|Jean-Luc<br />
|-<br />
| Oct 2<br />
|[https://zhizhenz.ece.illinois.edu/ Zhizhen Jane Zhao] (UIUC)<br />
|''[[Applied/ACMS/absF20#Zhizhen Jane Zhao (UIUC)|Exploiting Group and Geometric Structures for Massive Data Analysis]]''<br />
| Li & Chen<br />
|<br />
|<br />
|-<br />
| Oct 9<br />
|[https://igppweb.ucsd.edu/~mmorzfeld/ Matthias Morzfeld] (Scripps & UCSD)<br />
|''[[Applied/ACMS/absF20#Matthias Morzfeld (Scripps & UCSD)|What is Bayesian inference, why is it useful in Earth science and why is it challenging to do numerically?]]''<br />
| Chen<br />
|<br />
|<br />
|-<br />
| Oct 16<br />
|[https://jingweihu-math.github.io/webpage/ Jingwei Hu] (Purdue)<br />
|''[[Applied/ACMS/absF20#Jingwei Hu (Purdue)|A new stability and convergence proof of the Fourier-Galerkin spectral method for the spatially homogeneous Boltzmann equation]]''<br />
| Li<br />
|<br />
|-<br />
| Oct 23<br />
|[https://www.aos.wisc.edu/~dvimont/Home.html Dan Vimont] (UW-Madison, AOS)<br />
|''[[Applied/ACMS/absF20#Dan Vimont (UW-Madison, AOS)|Advances in Linear Inverse Modeling for Understanding Tropical Pacific Climate Variability]]''<br />
| Stechmann<br />
|<br />
|-<br />
| Oct 30<br />
|[http://www.dam.brown.edu/people/spsmith/ Sam Punshon-Smith] (Brown)<br />
|''[[Applied/ACMS/absF20#Sam Punshon-Smith (Brown)|Scalar mixing and the Batchelor spectrum in stochastic fluid mechanics]]''<br />
| Li<br />
|<br />
|-<br />
| Nov 6<br />
|[https://www.math.uci.edu/people/yimin-zhong Yimin Zhong] (UCI, Duke)<br />
|''[[Applied/ACMS/absF20#Yimin Zhong (UCI and Duke)|Quantitative PhotoAcoustic Tomography (PAT) with simplified PN approximation]]''<br />
|Li<br />
|<br />
|-<br />
| Nov 13<br />
|[https://www.cmu.edu/biolphys/deserno/ Markus Deserno] (CMU)<br />
|''[[Applied/ACMS/absF20#Markus Deserno (CMU)|Spontaneous curvature, differential stress, and bending modulus of asymmetric lipid membranes]]''<br />
|Spagnolie<br />
|-<br />
| Nov 20<br />
|[https://www.usna.edu/Users/math/lunasin/index.php/ Evelyn Lunasin] (USNA)<br />
|''[[Applied/ACMS/absF20#Evelyn Lunasin (USNA)|TBD]]''<br />
|Jean-Luc & Chen<br />
|-<br />
| Nov 27<br />
|''Thangksgiving recess''<br />
|<br />
|<br />
|-<br />
| Dec 4<br />
||[https://www.math.arizona.edu/people/chertkov Michael Chertkov] (U. Arizona)<br />
|''[[Applied/ACMS/absF20#Michael Chertkov (U Arizona)|TBD]]''<br />
|Zepeda-Nunez<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Future semesters ==<br />
<br />
*[[Applied/ACMS/Spring2021|Spring 2021]]<br />
<br />
<br />
----<br />
<br />
== Archived semesters ==<br />
<br />
*[[Applied/ACMS/Spring2020|Spring 2020]]<br />
*[[Applied/ACMS/Fall2019|Fall 2019]]<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absF20&diff=20170Applied/ACMS/absF202020-10-19T03:18:53Z<p>Qinli: /* ACMS Abstracts: Fall 2020 */</p>
<hr />
<div>= ACMS Abstracts: Fall 2020 =<br />
<br />
=== Nick Ouellette (Stanford) ===<br />
<br />
Title: Tensor Geometry in the Turbulent Cascade<br />
<br />
Abstract: Perhaps the defining characteristic of turbulent flows is the directed flux of energy from the scales at which it is injected into the flow to the scales at which it is dissipated. Often, we think about this transfer of energy in a Fourier sense; but in doing so, we obscure its mechanistic origins and lose any connection to the spatial structure of the flow field. Alternatively, quite a bit of work has been done to try to tie the cascade process to flow structures; but such approaches lead to results that seem to be at odds with observations. Here, I will discuss what we can learn from a different way of thinking about the cascade, this time as a purely mechanical process where some scales do work on others and thereby transfer energy. This interpretation highlights the fundamental importance of the geometric alignment between the turbulent stress tensor and the scale-local rate of strain tensor, since if they are misaligned with each other, no work can be done and no energy will be transferred. We find that (perhaps surprisingly) these two tensors are in general quite poorly aligned, making the cascade a highly inefficient process. Our analysis indicates that although some aspects of this tensor alignment are dynamical, the quadratic nature of Navier-Stokes nonlinearity and the embedding dimension provide significant constraints, with potential implications for turbulence modeling.<br />
<br />
=== Harry Lee (UW Madison) ===<br />
<br />
Title: Recent extension of V.I. Arnold's and J.L. Synge's mathematical theory of shear flows<br />
<br />
Abstract:<br />
A viscous extension of Arnold’s non-viscous theory ([1]) for 2D wall-bounded shear flows is established ([3]). One special form of our linearized viscous theory recaps the linear perturbation’s enstrophy (vorticity) identity derived by Synge in 1938 ([2]). For the first time in literature, we rigorously deduced the validity of Synge’s identity under nonlinear dynamics and relaxed wall conditions. Furthermore, we discovered a new ‘weighted’ enstrophy identity.<br />
<br />
To illustrate the physical relevance of our identities, we quantitatively investigated mechanisms of linear instability/stability within the normal modal framework. We observed a subtle interaction between a critical layer and its adjacent boundary layer, which governs stability/instability of a flow. We also proposed a boundary control scheme that transitions wall settings from no-slip to free-slip, through which the 2D base flow was stabilized quickly at an early stage of the transition. Effectiveness of such boundary control scheme for 3D shear flows is yet to be tested by DNS/experiments.<br />
<br />
Apart from physics, I shall also talk about the potential of using our nonlinear enstrophy identity to generate rigorous bounds on flow stability.<br />
<br />
References:<br />
<br />
[1] V. I. Arnold. Conditions for the nonlinear stability of the stationary plane curvilinear flows of an ideal fluid. Doklady Akademii Nauk, 162:975–978, 1965. URL: https://doi.org/10.1007/978-3-642-31031-7_4.<br />
<br />
[2] F. Fraternale, L. Domenicale, G. Staffilani, and D. Tordella. Internal waves in sheared flows: Lower bound of the vorticity growth and propagation discontinuities in the parameter space. Physical Review E, 97:063102, 2018. URL: https://doi.org/10.1103/PhysRevE.97.063102.<br />
<br />
[3] H. Lee and S. Wang. Extension of classical stability theory to viscous planar wall-bounded shear flows. Journal of Fluid Mechanics, 877:1134– 1162, 2019. URL: https://doi.org/10.1017/jfm.2019.629.<br />
<br />
=== Spencer Smith (Mount Holyoke) ===<br />
<br />
In active matter systems, energy consumed at the small scale by individual agents (like microtubules, bacteria, or birds) gives rise to emergent flows at large scales. Often these flows are chaotic and effectively mix the surrounding medium. In two dimensions, this mixing can be quantified by the topological entropy of the braids formed from the intertwining motion of particle trajectories. It is natural to ask how large this topological entropy, suitably normalized, can get, and what braiding patterns achieve this. For small numbers of particles on a line, or particles on an annulus, braids with topological entropies related to the golden and silver ratios respectively are maximal. Surprisingly, these braids arise in an active matter system: active nematic microtubules confined to an annulus have topological defects that move in trajectories compatible with the silver braid. However, it is unknown what braiding pattern of particles on the plane maximizes topological entropy in an analogous manner. We will investigate this issue in spatially periodic braids defined on planar lattices. Using a newly developed algorithm, we will give numerical evidence for a candidate planar lattice braiding pattern with maximal topological entropy. Using the version of this algorithm for arbitrary flows, we will also highlight a curious mixing phenomenon in the Vicsek active matter model.<br />
<br />
=== Zhizhen Jane Zhao (UIUC) ===<br />
<br />
Title: Exploiting Group and Geometric Structures for Massive Data Analysis<br />
<br />
Abstract: In this talk, I will introduce a new unsupervised learning framework for data points that lie on or close to a smooth manifold naturally equipped with a group action. In many applications, such as cryo-electron microscopy image analysis and shape analysis, the dataset of interest consists of images or shapes of potentially high spatial resolution, and admits a natural group action that plays the role of a nuisance or latent variable that needs to be quotient out before useful information is revealed. We estimate the pairwise group-invariant distance and the corresponding optimal alignment. We then construct a graph from the dataset, where each vertex represents a data point and the edges connect points with small group-invariant distance. In addition, each edge is associated with the estimated optimal alignment group. Inspired by the vector diffusion maps proposed by Singer and Wu, we explore the cycle consistency of the group transformations under multiple irreducible representations to define new similarity measures for the data. Utilizing the representation theoretic mechanism, multiple associated vector bundles can be constructed over the orbit space, providing multiple views for learning the geometry of the underlying base manifold from noisy observations. I will introduce three approaches to systematically combine the information from different representations, and show that by exploring the redundancy created across irreducible representations of the transformation group, we can significantly improve nearest neighbor identification, when a large portion of the true edge information are corrupted. I will also show the application in cryo-electron microscopy image analysis.<br />
<br />
<br />
=== Matthias Morzfeld (Scripps & UCSD) ===<br />
<br />
Title: What is Bayesian inference, why is it useful in Earth science and why is it challenging to do numerically?<br />
<br />
Abstract:<br />
I will first review Bayesian inference, which means to incorporate information from observations (data) into a numerical model, and will give some examples of applications in Earth science. The numerical solution of Bayesian inference problems is often based on sampling a posterior probability distribution. Sampling posterior distributions is difficult because these are usually high-dimensional (many parameters or states to estimate) and non-standard (e.g., not Gaussian). In particular a high-dimension causes numerical difficulties and slow convergence in many sampling algorithms. I will explain how ideas from numerical weather prediction can be leveraged to design Markov chain Monte Carlo (MCMC) samplers whose convergence rates are independent of the problem dimension for a well-defined class of problems.<br />
<br />
<br />
=== Jingwei Hu (Purdue) ===<br />
Title: A new stability and convergence proof of the Fourier-Galerkin spectral method for the spatially homogeneous Boltzmann equation<br />
<br />
ABstract: Numerical approximation of the Boltzmann equation is a challenging problem due to its high-dimensional, nonlocal, and nonlinear collision integral. Over the past decade, the Fourier-Galerkin spectral method has become a popular deterministic method for solving the Boltzmann equation, manifested by its high accuracy and potential of being further accelerated by the fast Fourier transform. Albeit its practical success, the stability of the method is only recently proved by Filbet, F. & Mouhot, C. in [Trans.Amer.Math.Soc. 363, no. 4 (2011): 1947-1980.] by utilizing the "spreading" property of the collision operator. In this work, we provide a new proof based on a careful L2 estimate of the negative part of the solution. We also discuss the applicability of the result to various initial data, including both continuous and discontinuous functions. This is joint work with Kunlun Qi and Tong Yang.<br />
<br />
=== Dan Vimont (UW-Madison, AOS) ===<br />
<br />
Title: Advances in Linear Inverse Modeling for Understanding Tropical Pacific Climate Variability<br />
<br />
Abstract:<br />
The El Nino / Southern Oscillation (ENSO) phenomenon in the tropical Pacific Ocean is the most energetic climatic phenomenon on Earth for interannual to decadal time scales, with substantial societal and environmental impacts around the world. Despite a well-developed theory for why ENSO events occur several aspects of ENSO variability are still poorly understood, including (1) why individual ENSO events tend to evolve with different spatial structures, (2) why ENSO events tend to be positively skewed (toward El Niño events rather than La Niña events), and (3) the role of deterministic dynamics vs. stochastic forcing in influencing ENSO growth and variance. In this talk, I will present recent work using a suite of Linear Inverse Models (LIMs) in which a linear dynamical operator (including state dependent noise, or cyclo-stationary dynamics) is derived from an existing set of observations. These LIMs can be used to (1) diagnose physical processes that cause growth toward a pre-defined spatial structure, (2) investigate how state-dependent (local) correlated additive and multiplicative noise (CAM-Noise) generates higher order moments (in a linear system forced by gaussian noise), and (3) the role of seasonality in generating ENSO variability and predictability. The talk will focus on development of the linear inverse model and on the application of the models in dynamical system analyses.<br />
<br />
=== Yimin Zhong (Duke) ===<br />
<br />
Title: Quantitative PhotoAcoustic Tomography (PAT) with simplified PN approximation<br />
<br />
Abstract: In this talk, I will first introduce the physical and biomedical background of the quantitative photoacoustic tomography (qPAT). The quantitative step has been traditionally using the diffusion approximation to solve but fails at many scenarios in practice. In recent years, more and more researches start to use the transport model to study this problem. However there are still some open problems relating to the uniqueness and stability estimates. We will try to study the qPAT with the simplified PN approximation which is regarded as a more accurate approximation than the simplest diffusion approximation. I will show that the uniqueness and stability estimates under this formulation. Numerical experiments are performed to validate the theory.</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=20169Applied/ACMS2020-10-19T03:17:56Z<p>Qinli: /* Fall 2020 */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li], [http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' Send mail to [mailto:acms+join@g-groups.wisc.edu acms+join@g-groups.wisc.edu].<br />
<br />
<br><br />
<br />
<br />
== Fall 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Sep 11<br />
|[https://cee.stanford.edu/people/nicholas-ouellette Nick Ouellette (Stanford)]<br />
|''[[Applied/ACMS/absF20#Nick Ouellette (Stanford)|Tensor Geometry in the Turbulent Cascade]]''<br />
|Jean-Luc<br />
|-<br />
| Sep 18<br />
|[https://www.researchgate.net/profile/Harry_Lee24 Harry Lee (UW-Madison and UMich)]<br />
|''[[Applied/ACMS/absF20#Harry Lee (UW-Madison, UMich)|Recent extension of V.I. Arnold's and J.L. Synge's mathematical theory of shear flows]]''<br />
|Wally<br />
|-<br />
| Sep 25<br />
|[https://www.mtholyoke.edu/people/spencer-smith Spencer Smith (Mount Holyoke)]<br />
|''[[Applied/ACMS/absF20#Spencer Smith (Mount Holyoke)|Braids on a lattice and maximally efficient mixing in active matter systems]]''<br />
|Jean-Luc<br />
|-<br />
| Oct 2<br />
|[https://zhizhenz.ece.illinois.edu/ Zhizhen Jane Zhao] (UIUC)<br />
|''[[Applied/ACMS/absF20#Zhizhen Jane Zhao (UIUC)|Exploiting Group and Geometric Structures for Massive Data Analysis]]''<br />
| Li & Chen<br />
|<br />
|<br />
|-<br />
| Oct 9<br />
|[https://igppweb.ucsd.edu/~mmorzfeld/ Matthias Morzfeld] (Scripps & UCSD)<br />
|''[[Applied/ACMS/absF20#Matthias Morzfeld (Scripps & UCSD)|What is Bayesian inference, why is it useful in Earth science and why is it challenging to do numerically?]]''<br />
| Chen<br />
|<br />
|<br />
|-<br />
| Oct 16<br />
|[https://jingweihu-math.github.io/webpage/ Jingwei Hu] (Purdue)<br />
|''[[Applied/ACMS/absF20#Jingwei Hu (Purdue)|A new stability and convergence proof of the Fourier-Galerkin spectral method for the spatially homogeneous Boltzmann equation]]''<br />
| Li<br />
|<br />
|-<br />
| Oct 23<br />
|[https://www.aos.wisc.edu/~dvimont/Home.html Dan Vimont] (UW-Madison, AOS)<br />
|''[[Applied/ACMS/absF20#Dan Vimont (UW-Madison, AOS)|Advances in Linear Inverse Modeling for Understanding Tropical Pacific Climate Variability]]''<br />
| Stechmann<br />
|<br />
|-<br />
| Oct 30<br />
|[http://www.dam.brown.edu/people/spsmith/ Sam Punshon-Smith] (Brown)<br />
|''[[Applied/ACMS/absF20#Sam Punshon-Smith (Brown)|TBD]]''<br />
| Li<br />
|<br />
|-<br />
| Nov 6<br />
|[https://www.math.uci.edu/people/yimin-zhong Yimin Zhong] (UCI, Duke)<br />
|''[[Applied/ACMS/absF20#Yimin Zhong (UCI and Duke)|Quantitative PhotoAcoustic Tomography (PAT) with simplified PN approximation]]''<br />
|Li<br />
|<br />
|-<br />
| Nov 13<br />
|[https://www.cmu.edu/biolphys/deserno/ Markus Deserno] (CMU)<br />
|''[[Applied/ACMS/absF20#Markus Deserno (CMU)|Spontaneous curvature, differential stress, and bending modulus of asymmetric lipid membranes]]''<br />
|Spagnolie<br />
|-<br />
| Nov 20<br />
|[https://www.usna.edu/Users/math/lunasin/index.php/ Evelyn Lunasin] (USNA)<br />
|''[[Applied/ACMS/absF20#Evelyn Lunasin (USNA)|TBD]]''<br />
|Jean-Luc & Chen<br />
|-<br />
| Nov 27<br />
|''Thangksgiving recess''<br />
|<br />
|<br />
|-<br />
| Dec 4<br />
||[https://www.math.arizona.edu/people/chertkov Michael Chertkov] (U. Arizona)<br />
|''[[Applied/ACMS/absF20#Michael Chertkov (U Arizona)|TBD]]''<br />
|Zepeda-Nunez<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Future semesters ==<br />
<br />
*[[Applied/ACMS/Spring2021|Spring 2021]]<br />
<br />
<br />
----<br />
<br />
== Archived semesters ==<br />
<br />
*[[Applied/ACMS/Spring2020|Spring 2020]]<br />
*[[Applied/ACMS/Fall2019|Fall 2019]]<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absF20&diff=20094Applied/ACMS/absF202020-10-07T20:53:59Z<p>Qinli: /* ACMS Abstracts: Fall 2020 */</p>
<hr />
<div>= ACMS Abstracts: Fall 2020 =<br />
<br />
=== Nick Ouellette (Stanford) ===<br />
<br />
Title: Tensor Geometry in the Turbulent Cascade<br />
<br />
Abstract: Perhaps the defining characteristic of turbulent flows is the directed flux of energy from the scales at which it is injected into the flow to the scales at which it is dissipated. Often, we think about this transfer of energy in a Fourier sense; but in doing so, we obscure its mechanistic origins and lose any connection to the spatial structure of the flow field. Alternatively, quite a bit of work has been done to try to tie the cascade process to flow structures; but such approaches lead to results that seem to be at odds with observations. Here, I will discuss what we can learn from a different way of thinking about the cascade, this time as a purely mechanical process where some scales do work on others and thereby transfer energy. This interpretation highlights the fundamental importance of the geometric alignment between the turbulent stress tensor and the scale-local rate of strain tensor, since if they are misaligned with each other, no work can be done and no energy will be transferred. We find that (perhaps surprisingly) these two tensors are in general quite poorly aligned, making the cascade a highly inefficient process. Our analysis indicates that although some aspects of this tensor alignment are dynamical, the quadratic nature of Navier-Stokes nonlinearity and the embedding dimension provide significant constraints, with potential implications for turbulence modeling.<br />
<br />
=== Harry Lee (UW Madison) ===<br />
<br />
Title: Recent extension of V.I. Arnold's and J.L. Synge's mathematical theory of shear flows<br />
<br />
Abstract:<br />
A viscous extension of Arnold’s non-viscous theory ([1]) for 2D wall-bounded shear flows is established ([3]). One special form of our linearized viscous theory recaps the linear perturbation’s enstrophy (vorticity) identity derived by Synge in 1938 ([2]). For the first time in literature, we rigorously deduced the validity of Synge’s identity under nonlinear dynamics and relaxed wall conditions. Furthermore, we discovered a new ‘weighted’ enstrophy identity.<br />
<br />
To illustrate the physical relevance of our identities, we quantitatively investigated mechanisms of linear instability/stability within the normal modal framework. We observed a subtle interaction between a critical layer and its adjacent boundary layer, which governs stability/instability of a flow. We also proposed a boundary control scheme that transitions wall settings from no-slip to free-slip, through which the 2D base flow was stabilized quickly at an early stage of the transition. Effectiveness of such boundary control scheme for 3D shear flows is yet to be tested by DNS/experiments.<br />
<br />
Apart from physics, I shall also talk about the potential of using our nonlinear enstrophy identity to generate rigorous bounds on flow stability.<br />
<br />
References:<br />
<br />
[1] V. I. Arnold. Conditions for the nonlinear stability of the stationary plane curvilinear flows of an ideal fluid. Doklady Akademii Nauk, 162:975–978, 1965. URL: https://doi.org/10.1007/978-3-642-31031-7_4.<br />
<br />
[2] F. Fraternale, L. Domenicale, G. Staffilani, and D. Tordella. Internal waves in sheared flows: Lower bound of the vorticity growth and propagation discontinuities in the parameter space. Physical Review E, 97:063102, 2018. URL: https://doi.org/10.1103/PhysRevE.97.063102.<br />
<br />
[3] H. Lee and S. Wang. Extension of classical stability theory to viscous planar wall-bounded shear flows. Journal of Fluid Mechanics, 877:1134– 1162, 2019. URL: https://doi.org/10.1017/jfm.2019.629.<br />
<br />
=== Spencer Smith (Mount Holyoke) ===<br />
<br />
In active matter systems, energy consumed at the small scale by individual agents (like microtubules, bacteria, or birds) gives rise to emergent flows at large scales. Often these flows are chaotic and effectively mix the surrounding medium. In two dimensions, this mixing can be quantified by the topological entropy of the braids formed from the intertwining motion of particle trajectories. It is natural to ask how large this topological entropy, suitably normalized, can get, and what braiding patterns achieve this. For small numbers of particles on a line, or particles on an annulus, braids with topological entropies related to the golden and silver ratios respectively are maximal. Surprisingly, these braids arise in an active matter system: active nematic microtubules confined to an annulus have topological defects that move in trajectories compatible with the silver braid. However, it is unknown what braiding pattern of particles on the plane maximizes topological entropy in an analogous manner. We will investigate this issue in spatially periodic braids defined on planar lattices. Using a newly developed algorithm, we will give numerical evidence for a candidate planar lattice braiding pattern with maximal topological entropy. Using the version of this algorithm for arbitrary flows, we will also highlight a curious mixing phenomenon in the Vicsek active matter model.<br />
<br />
=== Zhizhen Jane Zhao (UIUC) ===<br />
<br />
Title: Exploiting Group and Geometric Structures for Massive Data Analysis<br />
<br />
Abstract: In this talk, I will introduce a new unsupervised learning framework for data points that lie on or close to a smooth manifold naturally equipped with a group action. In many applications, such as cryo-electron microscopy image analysis and shape analysis, the dataset of interest consists of images or shapes of potentially high spatial resolution, and admits a natural group action that plays the role of a nuisance or latent variable that needs to be quotient out before useful information is revealed. We estimate the pairwise group-invariant distance and the corresponding optimal alignment. We then construct a graph from the dataset, where each vertex represents a data point and the edges connect points with small group-invariant distance. In addition, each edge is associated with the estimated optimal alignment group. Inspired by the vector diffusion maps proposed by Singer and Wu, we explore the cycle consistency of the group transformations under multiple irreducible representations to define new similarity measures for the data. Utilizing the representation theoretic mechanism, multiple associated vector bundles can be constructed over the orbit space, providing multiple views for learning the geometry of the underlying base manifold from noisy observations. I will introduce three approaches to systematically combine the information from different representations, and show that by exploring the redundancy created across irreducible representations of the transformation group, we can significantly improve nearest neighbor identification, when a large portion of the true edge information are corrupted. I will also show the application in cryo-electron microscopy image analysis.<br />
<br />
<br />
=== Matthias Morzfeld (Scripps & UCSD) ===<br />
<br />
Title: What is Bayesian inference, why is it useful in Earth science and why is it challenging to do numerically?<br />
<br />
Abstract:<br />
I will first review Bayesian inference, which means to incorporate information from observations (data) into a numerical model, and will give some examples of applications in Earth science. The numerical solution of Bayesian inference problems is often based on sampling a posterior probability distribution. Sampling posterior distributions is difficult because these are usually high-dimensional (many parameters or states to estimate) and non-standard (e.g., not Gaussian). In particular a high-dimension causes numerical difficulties and slow convergence in many sampling algorithms. I will explain how ideas from numerical weather prediction can be leveraged to design Markov chain Monte Carlo (MCMC) samplers whose convergence rates are independent of the problem dimension for a well-defined class of problems.<br />
<br />
<br />
=== Jingwei Hu (Purdue) ===<br />
Title: A new stability and convergence proof of the Fourier-Galerkin spectral method for the spatially homogeneous Boltzmann equation<br />
<br />
ABstract: Numerical approximation of the Boltzmann equation is a challenging problem due to its high-dimensional, nonlocal, and nonlinear collision integral. Over the past decade, the Fourier-Galerkin spectral method has become a popular deterministic method for solving the Boltzmann equation, manifested by its high accuracy and potential of being further accelerated by the fast Fourier transform. Albeit its practical success, the stability of the method is only recently proved by Filbet, F. & Mouhot, C. in [Trans.Amer.Math.Soc. 363, no. 4 (2011): 1947-1980.] by utilizing the "spreading" property of the collision operator. In this work, we provide a new proof based on a careful L2 estimate of the negative part of the solution. We also discuss the applicability of the result to various initial data, including both continuous and discontinuous functions. This is joint work with Kunlun Qi and Tong Yang.<br />
<br />
=== Dan Vimont (UW-Madison, AOS) ===<br />
<br />
Title: Advances in Linear Inverse Modeling for Understanding Tropical Pacific Climate Variability<br />
<br />
Abstract:<br />
The El Nino / Southern Oscillation (ENSO) phenomenon in the tropical Pacific Ocean is the most energetic climatic phenomenon on Earth for interannual to decadal time scales, with substantial societal and environmental impacts around the world. Despite a well-developed theory for why ENSO events occur several aspects of ENSO variability are still poorly understood, including (1) why individual ENSO events tend to evolve with different spatial structures, (2) why ENSO events tend to be positively skewed (toward El Niño events rather than La Niña events), and (3) the role of deterministic dynamics vs. stochastic forcing in influencing ENSO growth and variance. In this talk, I will present recent work using a suite of Linear Inverse Models (LIMs) in which a linear dynamical operator (including state dependent noise, or cyclo-stationary dynamics) is derived from an existing set of observations. These LIMs can be used to (1) diagnose physical processes that cause growth toward a pre-defined spatial structure, (2) investigate how state-dependent (local) correlated additive and multiplicative noise (CAM-Noise) generates higher order moments (in a linear system forced by gaussian noise), and (3) the role of seasonality in generating ENSO variability and predictability. The talk will focus on development of the linear inverse model and on the application of the models in dynamical system analyses.</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=20093Applied/ACMS2020-10-07T20:52:54Z<p>Qinli: /* Fall 2020 */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li], [http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' Send mail to [mailto:acms+join@g-groups.wisc.edu acms+join@g-groups.wisc.edu].<br />
<br />
<br><br />
<br />
<br />
== Fall 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Sep 11<br />
|[https://cee.stanford.edu/people/nicholas-ouellette Nick Ouellette (Stanford)]<br />
|''[[Applied/ACMS/absF20#Nick Ouellette (Stanford)|Tensor Geometry in the Turbulent Cascade]]''<br />
|Jean-Luc<br />
|-<br />
| Sep 18<br />
|[https://www.researchgate.net/profile/Harry_Lee24 Harry Lee (UW-Madison and UMich)]<br />
|''[[Applied/ACMS/absF20#Harry Lee (UW-Madison, UMich)|Recent extension of V.I. Arnold's and J.L. Synge's mathematical theory of shear flows]]''<br />
|Wally<br />
|-<br />
| Sep 25<br />
|[https://www.mtholyoke.edu/people/spencer-smith Spencer Smith (Mount Holyoke)]<br />
|''[[Applied/ACMS/absF20#Spencer Smith (Mount Holyoke)|Braids on a lattice and maximally efficient mixing in active matter systems]]''<br />
|Jean-Luc<br />
|-<br />
| Oct 2<br />
|[https://zhizhenz.ece.illinois.edu/ Zhizhen Jane Zhao] (UIUC)<br />
|''[[Applied/ACMS/absF20#Zhizhen Jane Zhao (UIUC)|Exploiting Group and Geometric Structures for Massive Data Analysis]]''<br />
| Li & Chen<br />
|<br />
|<br />
|-<br />
| Oct 9<br />
|[https://igppweb.ucsd.edu/~mmorzfeld/ Matthias Morzfeld] (Scripps & UCSD)<br />
|''[[Applied/ACMS/absF20#Matthias Morzfeld (Scripps & UCSD)|What is Bayesian inference, why is it useful in Earth science and why is it challenging to do numerically?]]''<br />
| Chen<br />
|<br />
|<br />
|-<br />
| Oct 16<br />
|[https://jingweihu-math.github.io/webpage/ Jingwei Hu] (Purdue)<br />
|''[[Applied/ACMS/absF20#Jingwei Hu (Purdue)|A new stability and convergence proof of the Fourier-Galerkin spectral method for the spatially homogeneous Boltzmann equation]]''<br />
| Li<br />
|<br />
|-<br />
| Oct 23<br />
|[https://www.aos.wisc.edu/~dvimont/Home.html Dan Vimont] (UW-Madison, AOS)<br />
|''[[Applied/ACMS/absF20#Dan Vimont (UW-Madison, AOS)|Advances in Linear Inverse Modeling for Understanding Tropical Pacific Climate Variability]]''<br />
| Stechmann<br />
|<br />
|-<br />
| Oct 30<br />
|[http://www.dam.brown.edu/people/spsmith/ Sam Punshon-Smith] (Brown)<br />
|''[[Applied/ACMS/absF20#Sam Punshon-Smith (Brown)|TBD]]''<br />
| Li<br />
|<br />
|-<br />
| Nov 6<br />
|[https://www.math.uci.edu/people/yimin-zhong Yimin Zhong] (UCI, Duke)<br />
|''[[Applied/ACMS/absF20#Yimin Zhong (UCI and Duke)|TBD]]''<br />
|Li<br />
|<br />
|-<br />
| Nov 13<br />
|[https://www.cmu.edu/biolphys/deserno/ Markus Deserno] (CMU)<br />
|''[[Applied/ACMS/absF20#Markus Deserno (CMU)|Spontaneous curvature, differential stress, and bending modulus of asymmetric lipid membranes]]''<br />
|Spagnolie<br />
|-<br />
| Nov 20<br />
|[https://www.usna.edu/Users/math/lunasin/index.php/ Evelyn Lunasin] (USNA)<br />
|''[[Applied/ACMS/absF20#Evelyn Lunasin (USNA)|TBD]]''<br />
|Jean-Luc & Chen<br />
|-<br />
| Nov 27<br />
|<br />
|<br />
|<br />
|-<br />
| Dec 4<br />
||[https://www.math.arizona.edu/people/chertkov Michael Chertkov] (U. Arizona)<br />
|''[[Applied/ACMS/absF20#Michael Chertkov (U Arizona)|TBD]]''<br />
|Zepeda-Nunez<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Future semesters ==<br />
<br />
*[[Applied/ACMS/Spring2021|Spring 2021]]<br />
<br />
<br />
----<br />
<br />
== Archived semesters ==<br />
<br />
*[[Applied/ACMS/Spring2020|Spring 2020]]<br />
*[[Applied/ACMS/Fall2019|Fall 2019]]<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absF20&diff=19950Applied/ACMS/absF202020-09-24T18:36:56Z<p>Qinli: /* ACMS Abstracts: Fall 2020 */</p>
<hr />
<div>= ACMS Abstracts: Fall 2020 =<br />
<br />
=== Nick Ouellette (Stanford) ===<br />
<br />
Title: Tensor Geometry in the Turbulent Cascade<br />
<br />
Abstract: Perhaps the defining characteristic of turbulent flows is the directed flux of energy from the scales at which it is injected into the flow to the scales at which it is dissipated. Often, we think about this transfer of energy in a Fourier sense; but in doing so, we obscure its mechanistic origins and lose any connection to the spatial structure of the flow field. Alternatively, quite a bit of work has been done to try to tie the cascade process to flow structures; but such approaches lead to results that seem to be at odds with observations. Here, I will discuss what we can learn from a different way of thinking about the cascade, this time as a purely mechanical process where some scales do work on others and thereby transfer energy. This interpretation highlights the fundamental importance of the geometric alignment between the turbulent stress tensor and the scale-local rate of strain tensor, since if they are misaligned with each other, no work can be done and no energy will be transferred. We find that (perhaps surprisingly) these two tensors are in general quite poorly aligned, making the cascade a highly inefficient process. Our analysis indicates that although some aspects of this tensor alignment are dynamical, the quadratic nature of Navier-Stokes nonlinearity and the embedding dimension provide significant constraints, with potential implications for turbulence modeling.<br />
<br />
=== Harry Lee (UW Madison) ===<br />
<br />
Title: Recent extension of V.I. Arnold's and J.L. Synge's mathematical theory of shear flows<br />
<br />
Abstract:<br />
A viscous extension of Arnold’s non-viscous theory ([1]) for 2D wall-bounded shear flows is established ([3]). One special form of our linearized viscous theory recaps the linear perturbation’s enstrophy (vorticity) identity derived by Synge in 1938 ([2]). For the first time in literature, we rigorously deduced the validity of Synge’s identity under nonlinear dynamics and relaxed wall conditions. Furthermore, we discovered a new ‘weighted’ enstrophy identity.<br />
<br />
To illustrate the physical relevance of our identities, we quantitatively investigated mechanisms of linear instability/stability within the normal modal framework. We observed a subtle interaction between a critical layer and its adjacent boundary layer, which governs stability/instability of a flow. We also proposed a boundary control scheme that transitions wall settings from no-slip to free-slip, through which the 2D base flow was stabilized quickly at an early stage of the transition. Effectiveness of such boundary control scheme for 3D shear flows is yet to be tested by DNS/experiments.<br />
<br />
Apart from physics, I shall also talk about the potential of using our nonlinear enstrophy identity to generate rigorous bounds on flow stability.<br />
<br />
References:<br />
<br />
[1] V. I. Arnold. Conditions for the nonlinear stability of the stationary plane curvilinear flows of an ideal fluid. Doklady Akademii Nauk, 162:975–978, 1965. URL: https://doi.org/10.1007/978-3-642-31031-7_4.<br />
<br />
[2] F. Fraternale, L. Domenicale, G. Staffilani, and D. Tordella. Internal waves in sheared flows: Lower bound of the vorticity growth and propagation discontinuities in the parameter space. Physical Review E, 97:063102, 2018. URL: https://doi.org/10.1103/PhysRevE.97.063102.<br />
<br />
[3] H. Lee and S. Wang. Extension of classical stability theory to viscous planar wall-bounded shear flows. Journal of Fluid Mechanics, 877:1134– 1162, 2019. URL: https://doi.org/10.1017/jfm.2019.629.<br />
<br />
=== Spencer Smith (Mount Holyoke) ===<br />
<br />
In active matter systems, energy consumed at the small scale by individual agents (like microtubules, bacteria, or birds) gives rise to emergent flows at large scales. Often these flows are chaotic and effectively mix the surrounding medium. In two dimensions, this mixing can be quantified by the topological entropy of the braids formed from the intertwining motion of particle trajectories. It is natural to ask how large this topological entropy, suitably normalized, can get, and what braiding patterns achieve this. For small numbers of particles on a line, or particles on an annulus, braids with topological entropies related to the golden and silver ratios respectively are maximal. Surprisingly, these braids arise in an active matter system: active nematic microtubules confined to an annulus have topological defects that move in trajectories compatible with the silver braid. However, it is unknown what braiding pattern of particles on the plane maximizes topological entropy in an analogous manner. We will investigate this issue in spatially periodic braids defined on planar lattices. Using a newly developed algorithm, we will give numerical evidence for a candidate planar lattice braiding pattern with maximal topological entropy. Using the version of this algorithm for arbitrary flows, we will also highlight a curious mixing phenomenon in the Vicsek active matter model.<br />
<br />
=== Zhizhen Jane Zhao (UIUC) ===<br />
<br />
Title: Exploiting Group and Geometric Structures for Massive Data Analysis<br />
<br />
Abstract: In this talk, I will introduce a new unsupervised learning framework for data points that lie on or close to a smooth manifold naturally equipped with a group action. In many applications, such as cryo-electron microscopy image analysis and shape analysis, the dataset of interest consists of images or shapes of potentially high spatial resolution, and admits a natural group action that plays the role of a nuisance or latent variable that needs to be quotient out before useful information is revealed. We estimate the pairwise group-invariant distance and the corresponding optimal alignment. We then construct a graph from the dataset, where each vertex represents a data point and the edges connect points with small group-invariant distance. In addition, each edge is associated with the estimated optimal alignment group. Inspired by the vector diffusion maps proposed by Singer and Wu, we explore the cycle consistency of the group transformations under multiple irreducible representations to define new similarity measures for the data. Utilizing the representation theoretic mechanism, multiple associated vector bundles can be constructed over the orbit space, providing multiple views for learning the geometry of the underlying base manifold from noisy observations. I will introduce three approaches to systematically combine the information from different representations, and show that by exploring the redundancy created across irreducible representations of the transformation group, we can significantly improve nearest neighbor identification, when a large portion of the true edge information are corrupted. I will also show the application in cryo-electron microscopy image analysis.<br />
<br />
<br />
=== Matthias Morzfeld (Scripps & UCSD) ===<br />
<br />
Title: What is Bayesian inference, why is it useful in Earth science and why is it challenging to do numerically?<br />
<br />
Abstract:<br />
I will first review Bayesian inference, which means to incorporate information from observations (data) into a numerical model, and will give some examples of applications in Earth science. The numerical solution of Bayesian inference problems is often based on sampling a posterior probability distribution. Sampling posterior distributions is difficult because these are usually high-dimensional (many parameters or states to estimate) and non-standard (e.g., not Gaussian). In particular a high-dimension causes numerical difficulties and slow convergence in many sampling algorithms. I will explain how ideas from numerical weather prediction can be leveraged to design Markov chain Monte Carlo (MCMC) samplers whose convergence rates are independent of the problem dimension for a well-defined class of problems.<br />
<br />
=== Dan Vimont (UW-Madison, AOS) ===<br />
<br />
Title: Advances in Linear Inverse Modeling for Understanding Tropical Pacific Climate Variability<br />
<br />
Abstract:<br />
The El Nino / Southern Oscillation (ENSO) phenomenon in the tropical Pacific Ocean is the most energetic climatic phenomenon on Earth for interannual to decadal time scales, with substantial societal and environmental impacts around the world. Despite a well-developed theory for why ENSO events occur several aspects of ENSO variability are still poorly understood, including (1) why individual ENSO events tend to evolve with different spatial structures, (2) why ENSO events tend to be positively skewed (toward El Niño events rather than La Niña events), and (3) the role of deterministic dynamics vs. stochastic forcing in influencing ENSO growth and variance. In this talk, I will present recent work using a suite of Linear Inverse Models (LIMs) in which a linear dynamical operator (including state dependent noise, or cyclo-stationary dynamics) is derived from an existing set of observations. These LIMs can be used to (1) diagnose physical processes that cause growth toward a pre-defined spatial structure, (2) investigate how state-dependent (local) correlated additive and multiplicative noise (CAM-Noise) generates higher order moments (in a linear system forced by gaussian noise), and (3) the role of seasonality in generating ENSO variability and predictability. The talk will focus on development of the linear inverse model and on the application of the models in dynamical system analyses.</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=19949Applied/ACMS2020-09-24T18:35:57Z<p>Qinli: /* Fall 2020 */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li], [http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' Send mail to [mailto:acms+join@g-groups.wisc.edu acms+join@g-groups.wisc.edu].<br />
<br />
<br><br />
<br />
<br />
== Fall 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Sep 11<br />
|[https://cee.stanford.edu/people/nicholas-ouellette Nick Ouellette (Stanford)]<br />
|''[[Applied/ACMS/absF20#Nick Ouellette (Stanford)|Tensor Geometry in the Turbulent Cascade]]''<br />
|Jean-Luc<br />
|-<br />
| Sep 18<br />
|[https://www.researchgate.net/profile/Harry_Lee24 Harry Lee (UW-Madison and UMich)]<br />
|''[[Applied/ACMS/absF20#Harry Lee (UW-Madison, UMich)|Recent extension of V.I. Arnold's and J.L. Synge's mathematical theory of shear flows]]''<br />
|Wally<br />
|-<br />
| Sep 25<br />
|[https://www.mtholyoke.edu/people/spencer-smith Spencer Smith (Mount Holyoke)]<br />
|''[[Applied/ACMS/absF20#Spencer Smith (Mount Holyoke)|Braids on a lattice and maximally efficient mixing in active matter systems]]''<br />
|Jean-Luc<br />
|-<br />
| Oct 2<br />
|[https://zhizhenz.ece.illinois.edu/ Zhizhen Jane Zhao] (UIUC)<br />
|''[[Applied/ACMS/absF20#Zhizhen Jane Zhao (UIUC)|Exploiting Group and Geometric Structures for Massive Data Analysis]]''<br />
| Li & Chen<br />
|<br />
|<br />
|-<br />
| Oct 9<br />
|[https://igppweb.ucsd.edu/~mmorzfeld/ Matthias Morzfeld] (Scripps & UCSD)<br />
|''[[Applied/ACMS/absF20#Matthias Morzfeld (Scripps & UCSD)|What is Bayesian inference, why is it useful in Earth science and why is it challenging to do numerically?]]''<br />
| Chen<br />
|<br />
|<br />
|-<br />
| Oct 16<br />
|[https://jingweihu-math.github.io/webpage/ Jingwei Hu] (Purdue)<br />
|''[[Applied/ACMS/absF20#Jingwei Hu (Purdue)|TBD]]''<br />
| Li<br />
|<br />
|-<br />
| Oct 23<br />
|[https://www.aos.wisc.edu/~dvimont/Home.html Dan Vimont] (UW-Madison, AOS)<br />
|''[[Applied/ACMS/absF20#Dan Vimont (UW-Madison, AOS)|Advances in Linear Inverse Modeling for Understanding Tropical Pacific Climate Variability]]''<br />
| Stechmann<br />
|<br />
|-<br />
| Oct 30<br />
|[http://www.dam.brown.edu/people/spsmith/ Sam Punshon-Smith] (Brown)<br />
|''[[Applied/ACMS/absF20#Sam Punshon-Smith (Brown)|TBD]]''<br />
| Li<br />
|<br />
|-<br />
| Nov 6<br />
|[https://www.math.uci.edu/people/yimin-zhong Yimin Zhong] (UCI, Duke)<br />
|''[[Applied/ACMS/absF20#Yimin Zhong (UCI and Duke)|TBD]]''<br />
|Li<br />
|<br />
|-<br />
| Nov 13<br />
|[https://www.cmu.edu/biolphys/deserno/ Markus Deserno] (CMU)<br />
|''[[Applied/ACMS/absF20#Markus Deserno (CMU)|Spontaneous curvature, differential stress, and bending modulus of asymmetric lipid membranes]]''<br />
|Spagnolie<br />
|-<br />
| Nov 20<br />
|[https://www.usna.edu/Users/math/lunasin/index.php/ Evelyn Lunasin] (USNA)<br />
|''[[Applied/ACMS/absF20#Evelyn Lunasin (USNA)|TBD]]''<br />
|Jean-Luc & Chen<br />
|-<br />
| Nov 27<br />
|<br />
|<br />
|<br />
|-<br />
| Dec 4<br />
||[https://www.math.arizona.edu/people/chertkov Michael Chertkov] (U. Arizona)<br />
|''[[Applied/ACMS/absF20#Michael Chertkov (U Arizona)|TBD]]''<br />
|Zepeda-Nunez<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Future semesters ==<br />
<br />
*[[Applied/ACMS/Spring2021|Spring 2021]]<br />
<br />
<br />
----<br />
<br />
== Archived semesters ==<br />
<br />
*[[Applied/ACMS/Spring2020|Spring 2020]]<br />
*[[Applied/ACMS/Fall2019|Fall 2019]]<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/Spring2021&diff=19798Applied/ACMS/Spring20212020-09-14T17:18:54Z<p>Qinli: /* Spring 2021 */</p>
<hr />
<div>== Spring 2021 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 29<br />
|<br />
|<br />
|<br />
|-<br />
| Feb 5<br />
|<br />
|<br />
|<br />
|-<br />
| Feb 12<br />
|<br />
|<br />
|<br />
|-<br />
| Feb 19<br />
|<br />
|<br />
|<br />
|-<br />
| Feb 26<br />
|<br />
|<br />
|<br />
|-<br />
| Mar 5<br />
|<br />
|<br />
|<br />
|-<br />
| Mar 12<br />
|[https://www.math.umass.edu/directory/faculty/yulong-lu Yulong Lu] (University of Massachusetts)<br />
|''[[Applied/ACMS/absS21#Yulong Lu (University of Massachusetts)|TBA]]''<br />
|Li<br />
|-<br />
| Mar 19<br />
|<br />
|<br />
|<br />
|-<br />
| Mar 26<br />
|(spring break)<br />
|<br />
|<br />
|-<br />
| Apr 2<br />
|<br />
|<br />
|<br />
|-<br />
| Apr 9<br />
|<br />
|<br />
|<br />
|-<br />
| Apr 16<br />
|<br />
|<br />
|<br />
|-<br />
| Apr 23<br />
|<br />
|<br />
|<br />
|-<br />
|}</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=19665Applied/ACMS2020-09-08T20:12:36Z<p>Qinli: /* Fall 2020 */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li], [http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' Send mail to [mailto:acms+join@g-groups.wisc.edu acms+join@g-groups.wisc.edu].<br />
<br />
<br><br />
<br />
<br />
== Fall 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Sep 11<br />
|[https://cee.stanford.edu/people/nicholas-ouellette Nick Ouellette] (Stanford)<br />
|''[[Applied/ACMS/absF20#Nick Ouellette (Stanford)|Tensor Geometry in the Turbulent Cascade]]''<br />
|Jean-Luc<br />
|-<br />
| Sep 18<br />
|[https://www.researchgate.net/profile/Harry_Lee24 Harry Lee] (UW-Madison and UMich)<br />
|''[[Applied/ACMS/absF20#Harry Lee (UW-Madison, UMich)|Recent extension of V.I. Arnold's and J.L. Synge's mathematical theory of shear flows]]''<br />
|Wally<br />
|-<br />
| Sep 25<br />
|[https://www.mtholyoke.edu/people/spencer-smith Spencer Smith] (Mount Holyoke)<br />
|''[[Applied/ACMS/absF20#Spencer Smith (Mount Holyoke)|TBD]]''<br />
|Jean-Luc<br />
|-<br />
| Oct 2<br />
|[https://zhizhenz.ece.illinois.edu/ Zhizhen Jane Zhao] (UIUC)<br />
|''[[Applied/ACMS/absF20#Zhizhen Jane Zhao (UIUC)|TBD]]''<br />
| Li & Chen<br />
|<br />
|<br />
|-<br />
| Oct 9<br />
|[https://igppweb.ucsd.edu/~mmorzfeld/ Matthias Morzfeld] (Scripps & UCSD)<br />
|''[[Applied/ACMS/absF20#Matthias Morzfeld (Scripps & UCSD)|What is Bayesian inference, why is it useful in Earth science and why is it challenging to do numerically?]]''<br />
| Chen<br />
|<br />
|<br />
|-<br />
| Oct 16<br />
|[https://jingweihu-math.github.io/webpage/ Jingwei Hu] (Purdue)<br />
|''[[Applied/ACMS/absF20#Jingwei Hu (Purdue)|TBD]]''<br />
| Li<br />
|<br />
|-<br />
| Oct 23<br />
|[https://www.aos.wisc.edu/~dvimont/Home.html Dan Vimont] (UW-Madison, AOS)<br />
|''[[Applied/ACMS/absF20#Dan Vimont (UW-Madison, AOS)|Advances in Linear Inverse Modeling for Understanding Tropical Pacific Climate Variability]]''<br />
| Stechmann<br />
|<br />
|-<br />
| Oct 30<br />
|[http://www.dam.brown.edu/people/spsmith/ Sam Punshon-Smith] (Brown)<br />
|''[[Applied/ACMS/absF20#Sam Punshon-Smith (Brown)|TBD]]''<br />
| Li<br />
|<br />
|-<br />
| Nov 6<br />
|[https://www.math.uci.edu/people/yimin-zhong Yimin Zhong] (UCI, Duke)<br />
|''[[Applied/ACMS/absF20#Yimin Zhong (UCI and Duke)|TBD]]''<br />
|Li<br />
|<br />
|-<br />
| Nov 13<br />
|[https://www.cmu.edu/biolphys/deserno/ Markus Deserno] (CMU)<br />
|''[[Applied/ACMS/absF20#Markus Deserno (CMU)|Spontaneous curvature, differential stress, and bending modulus of asymmetric lipid membranes]]''<br />
|Spagnolie<br />
|-<br />
| Nov 20<br />
|<br />
|<br />
|<br />
|-<br />
| Nov 27<br />
|<br />
|<br />
|<br />
|-<br />
| Dec 4<br />
||[https://www.math.arizona.edu/people/chertkov Michael Chertkov] (U. Arizona)<br />
|''[[Applied/ACMS/absF20#Michael Chertkov (U Arizona)|TBD]]''<br />
|Zepeda-Nunez<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Future semesters ==<br />
<br />
*[[Applied/ACMS/Spring2021|Spring 2021]]<br />
<br />
<br />
----<br />
<br />
== Archived semesters ==<br />
<br />
*[[Applied/ACMS/Spring2020|Spring 2020]]<br />
*[[Applied/ACMS/Fall2019|Fall 2019]]<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=19568Applied/ACMS2020-08-24T17:01:27Z<p>Qinli: /* Fall 2020 */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li], [http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
<br />
== Fall 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Sep 11<br />
|[https://cee.stanford.edu/people/nicholas-ouellette Nick Ouellette] (Stanford)<br />
|''[[Applied/ACMS/absF20#Nick Ouellette (Stanford)|Tensor Geometry in the Turbulent Cascade]]''<br />
|Jean-Luc<br />
|-<br />
| Sep 18<br />
|[https://www.researchgate.net/profile/Harry_Lee24 Harry Lee] (UW-Madison and UMich)<br />
|''[[Applied/ACMS/absF20#Harry Lee (UW-Madison, UMich)|Recent extension of V.I. Arnold's and J.L. Synge's mathematical theory of shear flows]]''<br />
|Wally<br />
|-<br />
| Sep 25<br />
|[https://www.mtholyoke.edu/people/spencer-smith Spencer Smith] (Mount Holyoke)<br />
|''[[Applied/ACMS/absF20#Spencer Smith (Mount Holyoke)|TBD]]''<br />
|Jean-Luc<br />
|-<br />
| Oct 2<br />
|[https://zhizhenz.ece.illinois.edu/ Zhizhen Jane Zhao] (UIUC)<br />
|''[[Applied/ACMS/absF20#Zhizhen Jane Zhao (UIUC)|TBD]]''<br />
| Li & Chen<br />
|<br />
|<br />
|-<br />
| Oct 9<br />
|[https://igppweb.ucsd.edu/~mmorzfeld/ Matthias Morzfeld] (Scripps & UCSD)<br />
|''[[Applied/ACMS/absF20#Matthias Morzfeld (Scripps & UCSD)|TBD]]''<br />
| Chen<br />
|<br />
|<br />
|-<br />
| Oct 16<br />
|[https://jingweihu-math.github.io/webpage/ Jingwei Hu] (Purdue)<br />
|''[[Applied/ACMS/absF20#Jingwei Hu (Purdue)|TBD]]''<br />
| Li<br />
|<br />
|-<br />
| Oct 23<br />
|<br />
|<br />
|<br />
|-<br />
| Oct 30<br />
|<br />
|<br />
|<br />
|-<br />
| Nov 6<br />
|[https://www.math.uci.edu/people/yimin-zhong Yimin Zhong] (UCI, Duke)<br />
|''[[Applied/ACMS/absF20#Yimin Zhong (UCI and Duke)|TBD]]''<br />
|Li<br />
|<br />
|-<br />
| Nov 13<br />
|[https://www.cmu.edu/biolphys/deserno/ Markus Deserno] (CMU)<br />
|''[[Applied/ACMS/absF20#Markus Deserno (CMU)|Spontaneous curvature, differential stress, and bending modulus of asymmetric lipid membranes]]''<br />
|Spagnolie<br />
|-<br />
| Nov 20<br />
|<br />
|<br />
|<br />
|-<br />
| Nov 27<br />
|<br />
|<br />
|<br />
|-<br />
| Dec 4<br />
|<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Future semesters ==<br />
<br />
*[[Applied/ACMS/Spring2021|Spring 2021]]<br />
<br />
<br />
----<br />
<br />
== Archived semesters ==<br />
<br />
*[[Applied/ACMS/Spring2020|Spring 2020]]<br />
*[[Applied/ACMS/Fall2019|Fall 2019]]<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=19567Applied/ACMS2020-08-24T17:00:31Z<p>Qinli: /* Fall 2020 */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li], [http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
<br />
== Fall 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Sep 11<br />
|[https://cee.stanford.edu/people/nicholas-ouellette Nick Ouellette] (Stanford)<br />
|''[[Applied/ACMS/absF20#Nick Ouellette (Stanford)|Tensor Geometry in the Turbulent Cascade]]''<br />
|Jean-Luc<br />
|-<br />
| Sep 18<br />
|[https://www.researchgate.net/profile/Harry_Lee24 Harry Lee] (UW-Madison and UMich)<br />
|''[[Applied/ACMS/absF20#Harry Lee (UW-Madison, UMich)|Recent extension of V.I. Arnold's and J.L. Synge's mathematical theory of shear flows]]''<br />
|Wally<br />
|-<br />
| Sep 25<br />
|[https://www.mtholyoke.edu/people/spencer-smith Spencer Smith] (Mount Holyoke)<br />
|''[[Applied/ACMS/absF20#Spencer Smith (Mount Holyoke)|TBD]]''<br />
|Jean-Luc<br />
|-<br />
| Oct 2<br />
|[https://zhizhenz.ece.illinois.edu/ Zhizhen Jane Zhao] (UIUC)<br />
|''[[Applied/ACMS/absF20#Zhizhen Jane Zhao (UIUC)|TBD]]''<br />
| Li<br />
|<br />
|<br />
|-<br />
| Oct 9<br />
|[https://igppweb.ucsd.edu/~mmorzfeld/ Matthias Morzfeld] (Scripps & UCSD)<br />
|''[[Applied/ACMS/absF20#Matthias Morzfeld (Scripps & UCSD)|TBD]]''<br />
| Chen<br />
|<br />
|<br />
|-<br />
| Oct 16<br />
|[https://jingweihu-math.github.io/webpage/ Jingwei Hu] (Purdue)<br />
|''[[Applied/ACMS/absF20#Jingwei Hu (Purdue)|TBD]]''<br />
| Li<br />
|<br />
|-<br />
| Oct 23<br />
|<br />
|<br />
|<br />
|-<br />
| Oct 30<br />
|<br />
|<br />
|<br />
|-<br />
| Nov 6<br />
|[https://www.math.uci.edu/people/yimin-zhong Yimin Zhong] (UCI, Duke)<br />
|''[[Applied/ACMS/absF20#Yimin Zhong (UCI and Duke)|TBD]]''<br />
|Li<br />
|<br />
|-<br />
| Nov 13<br />
|[https://www.cmu.edu/biolphys/deserno/ Markus Deserno] (CMU)<br />
|''[[Applied/ACMS/absF20#Markus Deserno (CMU)|Spontaneous curvature, differential stress, and bending modulus of asymmetric lipid membranes]]''<br />
|Spagnolie<br />
|-<br />
| Nov 20<br />
|<br />
|<br />
|<br />
|-<br />
| Nov 27<br />
|<br />
|<br />
|<br />
|-<br />
| Dec 4<br />
|<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Future semesters ==<br />
<br />
*[[Applied/ACMS/Spring2021|Spring 2021]]<br />
<br />
<br />
----<br />
<br />
== Archived semesters ==<br />
<br />
*[[Applied/ACMS/Spring2020|Spring 2020]]<br />
*[[Applied/ACMS/Fall2019|Fall 2019]]<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=19528Applied/ACMS2020-08-11T20:55:25Z<p>Qinli: /* Fall 2020 */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li], [http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
<br />
== Fall 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Sep 11<br />
|[https://cee.stanford.edu/people/nicholas-ouellette Nick Ouellette] (Stanford)<br />
|''[[Applied/ACMS/absF20#Nick Ouellette (Stanford)|Tensor Geometry in the Turbulent Cascade]]''<br />
|Jean-Luc<br />
|-<br />
| Sep 18<br />
|[https://www.researchgate.net/profile/Harry_Lee24 Harry Lee] (UW-Madison and UMich)<br />
|''[[Applied/ACMS/absF20#Harry Lee (UW-Madison, UMich)|TBD]]''<br />
|Wally<br />
|-<br />
| Sep 25<br />
|[https://www.mtholyoke.edu/people/spencer-smith Spencer Smith] (Mount Holyoke)<br />
|''[[Applied/ACMS/absF20#Spencer Smith (Mount Holyoke)|TBD]]''<br />
|Jean-Luc<br />
|-<br />
| Oct 2<br />
|[https://zhizhenz.ece.illinois.edu/ Zhizhen Jane Zhao] (UIUC)<br />
|''[[Applied/ACMS/absF20#Zhizhen Jane Zhao (UIUC)|TBD]]''<br />
| Li<br />
|<br />
|<br />
|-<br />
| Oct 9<br />
|[https://igppweb.ucsd.edu/~mmorzfeld/ Matthias Morzfeld] (Scripps & UCSD)<br />
|''[[Applied/ACMS/absF20#Matthias Morzfeld (Scripps & UCSD)|TBD]]''<br />
| Chen<br />
|<br />
|<br />
|-<br />
| Oct 16<br />
|[https://jingweihu-math.github.io/webpage/ Jingwei Hu] (Purdue)<br />
|''[[Applied/ACMS/absF20#Jingwei Hu (Purdue)|TBD]]''<br />
| Li<br />
|<br />
|-<br />
| Oct 23<br />
|<br />
|<br />
|<br />
|-<br />
| Oct 30<br />
|<br />
|<br />
|<br />
|-<br />
| Nov 6<br />
|<br />
|<br />
|<br />
|-<br />
| Nov 13<br />
|<br />
|<br />
|<br />
|-<br />
| Nov 20<br />
|<br />
|<br />
|<br />
|-<br />
| Nov 27<br />
|<br />
|<br />
|<br />
|-<br />
| Dec 4<br />
|<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Future semesters ==<br />
<br />
*[[Applied/ACMS/Spring2021|Spring 2021]]<br />
<br />
<br />
----<br />
<br />
== Archived semesters ==<br />
<br />
*[[Applied/ACMS/Spring2020|Spring 2020]]<br />
*[[Applied/ACMS/Fall2019|Fall 2019]]<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=19527Applied/ACMS2020-08-11T20:38:23Z<p>Qinli: /* Fall 2020 */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li], [http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
<br />
== Fall 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Sep 11<br />
|[https://cee.stanford.edu/people/nicholas-ouellette Nick Ouellette] (Stanford)<br />
|''[[Applied/ACMS/absF20#Nick Ouellette (Stanford)|Tensor Geometry in the Turbulent Cascade]]''<br />
|Jean-Luc<br />
|-<br />
| Sep 18<br />
|[Harry Lee] (UW-Madison and UMich)<br />
|''[[Applied/ACMS/absF20#Harry Lee (UW-Madison, UMich)|TBD]]''<br />
|Wally<br />
|-<br />
| Sep 25<br />
|[https://www.mtholyoke.edu/people/spencer-smith Spencer Smith] (Mount Holyoke)<br />
|''[[Applied/ACMS/absF20#Spencer Smith (Mount Holyoke)|TBD]]''<br />
|Jean-Luc<br />
|-<br />
| Oct 2<br />
|[https://zhizhenz.ece.illinois.edu/ Zhizhen Jane Zhao] (UIUC)<br />
|''[[Applied/ACMS/absF20#Zhizhen Jane Zhao (UIUC)|TBD]]''<br />
| Li<br />
|<br />
|<br />
|-<br />
| Oct 9<br />
|[https://igppweb.ucsd.edu/~mmorzfeld/ Matthias Morzfeld] (Scripps & UCSD)<br />
|''[[Applied/ACMS/absF20#Matthias Morzfeld (Scripps & UCSD)|TBD]]''<br />
| Chen<br />
|<br />
|<br />
|-<br />
| Oct 16<br />
|[https://jingweihu-math.github.io/webpage/ Jingwei Hu] (Purdue)<br />
|''[[Applied/ACMS/absF20#Jingwei Hu (Purdue)|TBD]]''<br />
| Li<br />
|<br />
|-<br />
| Oct 23<br />
|<br />
|<br />
|<br />
|-<br />
| Oct 30<br />
|<br />
|<br />
|<br />
|-<br />
| Nov 6<br />
|<br />
|<br />
|<br />
|-<br />
| Nov 13<br />
|<br />
|<br />
|<br />
|-<br />
| Nov 20<br />
|<br />
|<br />
|<br />
|-<br />
| Nov 27<br />
|<br />
|<br />
|<br />
|-<br />
| Dec 4<br />
|<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Future semesters ==<br />
<br />
*[[Applied/ACMS/Spring2021|Spring 2021]]<br />
<br />
<br />
----<br />
<br />
== Archived semesters ==<br />
<br />
*[[Applied/ACMS/Spring2020|Spring 2020]]<br />
*[[Applied/ACMS/Fall2019|Fall 2019]]<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=19481Applied/ACMS2020-08-03T16:53:13Z<p>Qinli: /* Fall 2020 */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li], [http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
<br />
== Fall 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Sep 11<br />
|<br />
|<br />
|<br />
|-<br />
| Sep 18<br />
|<br />
|<br />
|<br />
|-<br />
| Sep 25<br />
|<br />
|<br />
|<br />
|-<br />
| Oct 2<br />
|[https://zhizhenz.ece.illinois.edu/ Zhizhen Jane Zhao] (UIUC)<br />
|''[[Applied/ACMS/absF20#Zhizhen Jane Zhao (UIUC)|TBD]]''<br />
| Li<br />
|<br />
|<br />
|-<br />
| Oct 9<br />
|[https://igppweb.ucsd.edu/~mmorzfeld/ Matthias Morzfeld] (Scripps & UCSD)<br />
|''[[Applied/ACMS/absF20#Matthias Morzfeld (Scripps & UCSD)|TBD]]''<br />
| Chen<br />
|<br />
|<br />
|-<br />
| Oct 16<br />
|[https://jingweihu-math.github.io/webpage/ Jingwei Hu] (Purdue)<br />
|''[[Applied/ACMS/absF20#Jingwei Hu (Purdue)|TBD]]''<br />
| Li<br />
|<br />
|-<br />
| Oct 23<br />
|<br />
|<br />
|<br />
|-<br />
| Oct 30<br />
|<br />
|<br />
|<br />
|-<br />
| Nov 6<br />
|<br />
|<br />
|<br />
|-<br />
| Nov 13<br />
|<br />
|<br />
|<br />
|-<br />
| Nov 20<br />
|<br />
|<br />
|<br />
|-<br />
| Nov 27<br />
|<br />
|<br />
|<br />
|-<br />
| Dec 4<br />
|<br />
|<br />
|<br />
|-<br />
|}<br />
<br />
== Future semesters ==<br />
<br />
*[[Applied/ACMS/Spring2021|Spring 2021]]<br />
<br />
<br />
----<br />
<br />
== Archived semesters ==<br />
<br />
*[[Applied/ACMS/Spring2020|Spring 2020]]<br />
*[[Applied/ACMS/Fall2019|Fall 2019]]<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=19281Applied/ACMS2020-03-20T15:21:02Z<p>Qinli: /* Spring 2020 */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li], [http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
<br />
== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 31<br />
|[https://www.math.wisc.edu/~hung/ Hung Tran] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Hung Tran (UW-Madison)| Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel]]''<br />
| Li<br />
|-<br />
| Feb 7<br />
|[https://www.usna.edu/Users/weaprcon/avramov/index.php Svetlana Avramov-Zamurovic] (United States Naval Academy)<br />
|''[[Applied/ACMS/absS20#Svetlana Avramov-Zamurovic (United States Naval Academy)|Experiments with Structured Light]]''<br />
| Stechmann<br />
|-<br />
| Feb 14<br />
|[http://math.mit.edu/~vadicgor/ Vadim Gorin] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Vadim Gorin (UW-Madison)| Integrability of KPZ equation]]''<br />
| Li<br />
|-<br />
| Feb 21<br />
|[http://www.personal.psu.edu/jzh13/ John Harlim] (Penn State University)<br />
|''[[Applied/ACMS/absS20#Speaker (Penn State University)|Modeling Dynamical Systems with Machine Learning]]''<br />
| Chen<br />
|-<br />
| Feb 28<br />
|[https://cims.nyu.edu/~yangq/ Qiu Yang] (NYU/UVic/NCAR)<br />
|''[[Applied/ACMS/absS20#Speaker (NYU/UVic/NCAR)|Upscale Impact of Mesoscale Convective Systems on the MJO and Its Parameterization in Coarse-Resolution GCMs]]''<br />
| Chen<br />
|-<br />
| Mar 6<br />
|[https://directory.engr.wisc.edu/ep/Faculty/Bronkhorst_Curt/ Curt Bronkhorst] (UW-Madison Engineering Physics)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|Computational Prediction of Shear Banding and Deformation Twinning in Metals]]''<br />
| Smith<br />
|-<br />
| Mar 13<br />
|[http://www.columbia.edu/~ktm2132/ Kyle Mandli] (Columbia)<br />
|''[[Applied/ACMS/absS20#Kyle Mandli (Columbia)|canceled]]''<br />
| Wally<br />
|-<br />
| Mar 20<br />
|[Spring break] (Spring Break!)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 27<br />
|[http://www-personal.umich.edu/~jcsch/ John Schotland] (U Mich)<br />
|''[[Applied/ACMS/absS20#John Schotland (Michigan)|canceled]]''<br />
| host<br />
|-<br />
| Apr 3<br />
|[http://keaton-burns.com/ Keaton Burns] (MIT)<br />
|''[[Applied/ACMS/absS20#Keaton Burns (MIT)| VIRTUAL! Details to come. ]]''<br />
| Spagnolie<br />
|-<br />
| Apr 10<br />
|[https://www.princeton.edu/~lecoanet/ Daniel Lecoanet] (Princeton)<br />
|''[[Applied/ACMS/absS20#Daniel Lecoanet (Princeton)|canceled]]''<br />
| Wally<br />
|-<br />
| Apr 17<br />
|[https://www.ornl.gov/staff-profile/hoang-tran Hoang Tran] (Oak Ridge National Laboratory)<br />
|''[[Applied/ACMS/absS20#Hoang Tran (institution)|canceled]]''<br />
| Tran<br />
|-<br />
| Apr 24<br />
|[https://www.pml.unc.edu/ Pedro Saenz] (UNC)<br />
|''[[Applied/ACMS/absF19#Pedro Saenz (UNC)|canceled]]''<br />
| Spagnolie<br />
|-<br />
|}<br />
<br />
== Future semesters ==<br />
<br />
<br />
<br />
<br />
----<br />
<br />
== Archived semesters ==<br />
<br />
*[[Applied/ACMS/Spring2020|Spring 2020]]<br />
*[[Applied/ACMS/Fall2019|Fall 2019]]<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=19280Applied/ACMS2020-03-20T15:19:50Z<p>Qinli: /* Spring 2020 */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li], [http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
<br />
== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 31<br />
|[https://www.math.wisc.edu/~hung/ Hung Tran] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Hung Tran (UW-Madison)| Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel]]''<br />
| Li<br />
|-<br />
| Feb 7<br />
|[https://www.usna.edu/Users/weaprcon/avramov/index.php Svetlana Avramov-Zamurovic] (United States Naval Academy)<br />
|''[[Applied/ACMS/absS20#Svetlana Avramov-Zamurovic (United States Naval Academy)|Experiments with Structured Light]]''<br />
| Stechmann<br />
|-<br />
| Feb 14<br />
|[http://math.mit.edu/~vadicgor/ Vadim Gorin] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Vadim Gorin (UW-Madison)| Integrability of KPZ equation]]''<br />
| Li<br />
|-<br />
| Feb 21<br />
|[http://www.personal.psu.edu/jzh13/ John Harlim] (Penn State University)<br />
|''[[Applied/ACMS/absS20#Speaker (Penn State University)|Modeling Dynamical Systems with Machine Learning]]''<br />
| Chen<br />
|-<br />
| Feb 28<br />
|[https://cims.nyu.edu/~yangq/ Qiu Yang] (NYU/UVic/NCAR)<br />
|''[[Applied/ACMS/absS20#Speaker (NYU/UVic/NCAR)|Upscale Impact of Mesoscale Convective Systems on the MJO and Its Parameterization in Coarse-Resolution GCMs]]''<br />
| Chen<br />
|-<br />
| Mar 6<br />
|[https://directory.engr.wisc.edu/ep/Faculty/Bronkhorst_Curt/ Curt Bronkhorst] (UW-Madison Engineering Physics)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|Computational Prediction of Shear Banding and Deformation Twinning in Metals]]''<br />
| Smith<br />
|-<br />
| Mar 13<br />
|[http://www.columbia.edu/~ktm2132/ Kyle Mandli, canceled] (Columbia)<br />
|''[[Applied/ACMS/absS20#Kyle Mandli (Columbia)|TBA]]''<br />
| Wally<br />
|-<br />
| Mar 20<br />
|[Spring break] (Spring Break!)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 27<br />
|[http://www-personal.umich.edu/~jcsch/ John Schotland, canceled] (U Mich)<br />
|''[[Applied/ACMS/absS20#John Schotland (Michigan)|title]]''<br />
| host<br />
|-<br />
| Apr 3<br />
|[http://keaton-burns.com/ Keaton Burns, canceled] (MIT)<br />
|''[[Applied/ACMS/absS20#Keaton Burns (MIT)| VIRTUAL! Details to come. ]]''<br />
| Spagnolie<br />
|-<br />
| Apr 10<br />
|[https://www.princeton.edu/~lecoanet/ Daniel Lecoanet, canceled] (Princeton)<br />
|''[[Applied/ACMS/absS20#Daniel Lecoanet (Princeton)|TBA]]''<br />
| Wally<br />
|-<br />
| Apr 17<br />
|[https://www.ornl.gov/staff-profile/hoang-tran Hoang Tran, canceled] (Oak Ridge National Laboratory)<br />
|''[[Applied/ACMS/absS20#Hoang Tran (institution)|title]]''<br />
| Tran<br />
|-<br />
| Apr 24<br />
|[https://www.pml.unc.edu/ Pedro Saenz, canceled] (UNC)<br />
|''[[Applied/ACMS/absF19#Pedro Saenz (UNC)|TBA]]''<br />
| Spagnolie<br />
|-<br />
|}<br />
<br />
== Future semesters ==<br />
<br />
<br />
<br />
<br />
----<br />
<br />
== Archived semesters ==<br />
<br />
*[[Applied/ACMS/Spring2020|Spring 2020]]<br />
*[[Applied/ACMS/Fall2019|Fall 2019]]<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=PDE_Geometric_Analysis_seminar&diff=19143PDE Geometric Analysis seminar2020-02-25T21:28:23Z<p>Qinli: /* PDE GA Seminar Schedule Fall 2019-Spring 2020 */</p>
<hr />
<div>The seminar will be held in room 901 of Van Vleck Hall on Mondays from 3:30pm - 4:30pm, unless indicated otherwise.<br />
<br />
===[[Previous PDE/GA seminars]]===<br />
===[[Fall 2020-Spring 2021 | Tentative schedule for Fall 2020-Spring 2021]]===<br />
<br />
== PDE GA Seminar Schedule Fall 2019-Spring 2020 ==<br />
<br />
<br />
{| cellpadding="8"<br />
!style="width:20%" align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!style="width:20%" align="left" | host(s)<br />
|- <br />
|Sep 9<br />
| Scott Smith (UW Madison)<br />
|[[#Scott Smith | Recent progress on singular, quasi-linear stochastic PDE ]]<br />
| Kim and Tran<br />
|- <br />
|Sep 14-15<br />
| <br />
|[[ # |AMS Fall Central Sectional Meeting https://www.ams.org/meetings/sectional/2267_program.html ]]<br />
| <br />
|- <br />
|Sep 23<br />
| Son Tu (UW Madison)<br />
|[[#Son Tu | State-Constraint static Hamilton-Jacobi equations in nested domains ]]<br />
| Kim and Tran<br />
|- <br />
|Sep 28-29, VV901<br />
| https://www.ki-net.umd.edu/content/conf?event_id=993<br />
| | Recent progress in analytical aspects of kinetic equations and related fluid models <br />
| <br />
|- <br />
|Oct 7<br />
| Jin Woo Jang (Postech)<br />
|[[#Jin Woo Jang| On a Cauchy problem for the Landau-Boltzmann equation ]]<br />
| Kim<br />
|- <br />
|Oct 14<br />
| Stefania Patrizi (UT Austin)<br />
|[[#Stefania Patrizi | Dislocations dynamics: from microscopic models to macroscopic crystal plasticity ]]<br />
| Tran<br />
|- <br />
|Oct 21<br />
| Claude Bardos (Université Paris Denis Diderot, France)<br />
|[[#Claude Bardos | From d'Alembert paradox to 1984 Kato criteria via 1941 1/3 Kolmogorov law and 1949 Onsager conjecture ]]<br />
| Li<br />
|- <br />
|Oct 25-27, VV901<br />
| https://www.ki-net.umd.edu/content/conf?event_id=1015<br />
|| Forward and Inverse Problems in Kinetic Theory <br />
| Li<br />
|- <br />
|Oct 28<br />
| Albert Ai (UW Madison)<br />
|[[#Albert Ai | Two dimensional gravity waves at low regularity: Energy estimates ]]<br />
| Ifrim<br />
|- <br />
|Nov 4<br />
| Yunbai Cao (UW Madison)<br />
|[[#Yunbai Cao | Vlasov-Poisson-Boltzmann system in Bounded Domains]]<br />
| Kim and Tran<br />
|- <br />
|Nov 18<br />
| Ilyas Khan (UW Madison)<br />
|[[#Ilyas Khan | The Uniqueness of Asymptotically Conical Self-Shrinkers in High Codimension ]]<br />
| Kim and Tran<br />
|-<br />
|Nov 25<br />
| Mathew Langford (UT Knoxville)<br />
|[[#Mathew Langford | Concavity of the arrival time ]]<br />
| Angenent<br />
|- <br />
|Dec 9 - Colloquium (4-5PM)<br />
| Hui Yu (Columbia)<br />
|[[#Hui Yu | TBA ]]<br />
| Tran<br />
|- <br />
|Feb. 3<br />
| Philippe LeFloch (Sorbonne University and CNRS)<br />
|[[#Philippe LeFloch | Nonlinear stability of self-gravitating matter under low decay and weak regularity conditions ]]<br />
| Feldman<br />
|- <br />
|Feb. 10<br />
| Joonhyun La (Stanford)<br />
|[[#Joonhyun La | On a kinetic model of polymeric fluids ]]<br />
| Kim<br />
|- <br />
|Feb 17<br />
| Yannick Sire (JHU)<br />
|[[#Yannick Sire | Minimizers for the thin one-phase free boundary problem ]]<br />
| Tran<br />
|- <br />
|Feb 19 - Colloquium (4-5PM)<br />
| Zhenfu Wang (University of Pennsylvania)<br />
|[[#Zhenfu Wang | Quantitative Methods for the Mean Field Limit Problem ]]<br />
| Tran<br />
|- <br />
|Feb 24<br />
| Matthew Schrecker (UW Madison)<br />
|[[#Matthew Schrecker | Existence theory and Newtonian limit for 1D relativistic Euler equations ]]<br />
| Feldman<br />
|- <br />
|March 2<br />
| Theodora Bourni (UT Knoxville)<br />
|[[#Speaker | TBA ]]<br />
| Angenent<br />
|- <br />
|March 3 -- Analysis seminar<br />
| William Green (Rose-Hulman Institute of Technology)<br />
|[[#William Green | Dispersive estimates for the Dirac equation ]]<br />
| Betsy Stovall<br />
|-<br />
|March 9<br />
| Ian Tice (CMU)<br />
|[[#Ian Tice| TBA ]]<br />
| Kim<br />
|- <br />
|March 16 <br />
| No seminar (spring break)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|- <br />
|March 23<br />
| Jared Speck (Vanderbilt)<br />
|[[#Jared Speck | TBA ]]<br />
| Schrecker<br />
|- <br />
|March 30<br />
| Huy Nguyen (Brown)<br />
|[[#Huy Nguyen | TBA ]]<br />
| organizer<br />
|- <br />
|April 6<br />
| Speaker (Institute)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|- <br />
|April 13<br />
| Hyunju Kwon (IAS)<br />
|[[#Hyunju Kwon | TBA ]]<br />
| Kim<br />
|- <br />
|April 20<br />
| Adrian Tudorascu (WVU)<br />
|[[#Adrian Tudorascu | On the Lagrangian description of the Sticky Particle flow ]]<br />
| Feldman<br />
|- <br />
|April 27<br />
| Christof Sparber (UIC)<br />
|[[#Christof Sparber | TBA ]]<br />
| Host<br />
|- <br />
|May 18-21<br />
| Madison Workshop in PDE 2020<br />
|[[#Speaker | TBA ]]<br />
| Tran<br />
|}<br />
<br />
== Abstracts ==<br />
<br />
===Scott Smith===<br />
<br />
Title: Recent progress on singular, quasi-linear stochastic PDE<br />
<br />
Abstract: This talk with focus on quasi-linear parabolic equations with an irregular forcing . These equations are ill-posed in the traditional sense of distribution theory. They require flexibility in the notion of solution as well as new a priori bounds. Drawing on the philosophy of rough paths and regularity structures, we develop the analytic part of a small data solution theory. This is joint work with Felix Otto, Hendrik Weber, and Jonas Sauer.<br />
<br />
<br />
===Son Tu===<br />
<br />
Title: State-Constraint static Hamilton-Jacobi equations in nested domains<br />
<br />
Abstract: We study state-constraint static Hamilton-Jacobi equations in a sequence of domains $\{\Omega_k\}$ in $\mathbb R^n$ such that $\Omega_k \subset \Omega_{k+1}$ for all $k \in \mathbb N$. We obtain rates of convergence of $u_k$, the solution to the state-constraint problem in $\Omega_k$, to $u$, the solution to the corresponding problem in $\Omega=\bigcup_k \Omega_k$. In many cases, the rates obtained are proven to be optimal (it's a joint work with Yeoneung Kim and Hung V. Tran).<br />
<br />
<br />
===Jin Woo Jang===<br />
<br />
Title: On a Cauchy problem for the Landau-Boltzmann equation<br />
<br />
Abstract: In this talk, I will introduce a recent development in the global well-posedness of the Landau equation (1936) in a general smooth bounded domain, which has been a long-outstanding open problem. This work proves the global stability of the Landau equation in an $L^\infty_{x,v}$ framework with the Coulombic potential in a general smooth bounded domain with the specular reflection boundary condition for initial perturbations of the Maxwellian equilibrium states. Our methods consist of the generalization of the well-posedness theory for the kinetic Fokker-Planck equation (HJV-2014, HJJ-2018) and the extension of the boundary value problem to a whole space problem, as well as the use of a recent extension of De Giorgi-Nash-Moser theory for the kinetic Fokker-Planck equations (GIMV-2016) and the Morrey estimates (BCM-1996) to further control the velocity derivatives, which ensures the uniqueness. This is a joint work with Y. Guo, H. J. Hwang, and Z. Ouyang.<br />
<br />
<br />
===Stefania Patrizi===<br />
<br />
Title: <br />
Dislocations dynamics: from microscopic models to macroscopic crystal plasticity<br />
<br />
Abstract: Dislocation theory aims at explaining the plastic behavior of materials by the motion of line defects in crystals. Peierls-Nabarro models consist in approximating the geometric motion of these defects by nonlocal reaction-diffusion equations. We study the asymptotic limit of solutions of Peierls-Nabarro equations. Different scalings lead to different models at microscopic, mesoscopic and macroscopic scale. This is joint work with E. Valdinoci.<br />
<br />
<br />
===Claude Bardos===<br />
Title: From the d'Alembert paradox to the 1984 Kato criteria via the 1941 $1/3$ Kolmogorov law and the 1949 Onsager conjecture<br />
<br />
Abstract: Several of my recent contributions, with Marie Farge, Edriss Titi, Emile Wiedemann, Piotr and Agneska Gwiadza, were motivated by the following issues: The role of boundary effect in mathematical theory of fluids mechanic and the similarity, in presence of these effects, of the weak convergence in the zero viscosity limit and the statistical theory of turbulence. As a consequence, I will recall the Onsager conjecture and compare it to the issue of anomalous energy dissipation.<br />
<br />
Then I will give a proof of the local conservation of energy under convenient hypothesis in a domain with boundary and give supplementary condition that imply the global conservation of energy in a domain with boundary and the absence of anomalous energy dissipation in the zero viscosity limit of solutions of the Navier-Stokes equation in the presence of no slip boundary condition.<br />
<br />
Eventually the above results are compared with several forms of a basic theorem of Kato in the presence of a Lipschitz solution of the Euler equations and one may insist on the fact that in such case the the absence of anomalous energy dissipation is {\bf equivalent} to the persistence of regularity in the zero viscosity limit. Eventually this remark contributes to the resolution of the d'Alembert Paradox.<br />
<br />
===Albert Ai===<br />
Title: Two dimensional gravity waves at low regularity: Energy estimates<br />
<br />
Abstract: In this talk, we will consider the gravity water wave equations in two space dimensions. Our focus is on sharp cubic energy estimates and low regularity solutions. Precisely, we will introduce techniques to prove a new class of energy estimates, which we call balanced cubic estimates. This yields a key improvement over the earlier cubic estimates of Hunter-Ifrim-Tataru, while preserving their scale invariant character and their position-velocity potential holomorphic coordinate formulation. Even without using Strichartz estimates, these results allow us to significantly lower the Sobolev regularity threshold for local well-posedness. This is joint work with Mihaela Ifrim and Daniel Tataru.<br />
<br />
===Ilyas Khan===<br />
Title: The Uniqueness of Asymptotically Conical Self-Shrinkers in High Codimension.<br />
<br />
Abstract: In this talk, we will consider self-shrinking solitons of the mean curvature flow that are smoothly asymptotic to a Riemannian cone in $\mathbb{R}^n$. In 2011, L. Wang proved the uniqueness of self-shrinking ends asymptotic to a cone $C$ in the case of hypersurfaces (codimension 1) by using a backwards uniqueness result for the heat equation due to Escauriaza, Sverak, and Seregin. Later, J. Bernstein proved the same fact using purely elliptic methods. We consider the case of self-shrinkers in high codimension, and outline how to prove the same uniqueness result in this significantly more general case, by using geometric arguments and extending Bernstein’s result.<br />
<br />
===Mathew Langford===<br />
Title: Concavity of the arrival time<br />
<br />
Abstract: We present a simple connection between differential Harnack inequalities for hypersurface flows and natural concavity properties of their time-of-arrival functions. We prove these concavity properties directly for a large class of flows by applying a novel concavity maximum principle argument to the corresponding level set flow equations. In particular, this yields a short proof of Hamilton’s differential Harnack inequality for mean curvature flow and, more generally, Andrews’ differential Harnack inequalities for certain “$\alpha$-inverse-concave” flows.<br />
<br />
===Philippe LeFloch===<br />
Title: Nonlinear stability of self-gravitating matter under low decay and weak regularity conditions<br />
<br />
Abstract: I will present recent progress on the global evolution problem for self-gravitating matter. (1) For Einstein's constraint equations, motivated by a scheme proposed by Carlotto and Schoen I will show the existence of asymptotically Euclidean Einstein spaces with low decay; joint work with T. Nguyen. <br />
<br />
(2) For Einstein's evolution equations in the regime near Minkowski spacetime, I will show the global nonlinear stability of massive matter fields; joint work with Y. Ma. <br />
<br />
(3) For the colliding gravitational wave problem, I will show the existence of weakly regular spacetimes containing geometric singularities across which junction conditions are imposed; joint work with B. Le Floch and G. Veneziano.<br />
<br />
<br />
===Joonhyun La===<br />
Title: On a kinetic model of polymeric fluids<br />
<br />
Abstract: In this talk, we prove global well-posedness of a system describing behavior of dilute flexible polymeric fluids. This model is based on kinetic theory, and a main difficulty for this system is its multi-scale nature. A new function space, based on moments, is introduced to address this issue, and this function space allows us to deal with larger initial data.<br />
<br />
<br />
===Yannick Sire===<br />
Title: Minimizers for the thin one-phase free boundary problem<br />
<br />
Abstract: We consider the thin one-phase free boundary problem, associated to minimizing a weighted Dirichlet energy of thefunction in the half-space plus the area of the positivity set of that function restricted to the boundary. I will provide a rather complete picture of the (partial ) regularity of the free boundary, providing content and structure estimates on the singular set of the free boundary when it exists. All of these results hold for the full range of the relevant weight related to an anomalous diffusion on the boundary. The approach does not follow the standard one introduced in the seminal work of Alt and Caffarelli. Instead, the nonlocal nature of the distributional measure associated to a minimizer necessitates arguments which are less reliant on the underlying PDE. This opens several directions of research that I will try to describe. <br />
<br />
===Matthew Schrecker===<br />
Title: Existence theory and Newtonian limit for 1D relativistic Euler equations<br />
<br />
Abstract: I will present the results of my recent work with Gui-Qiang Chen on the Euler equations in the conditions of special relativity. I will show how the theory of compensated compactness may be used to obtain the existence of entropy solutions to this system. Moreover, it is expected that as the light speed grows to infinity, solutions to the relativistic Euler equations will converge to their classical (Newtonian) counterparts. The theory we develop is also sufficient to demonstrate this convergence rigorously.<br />
<br />
===Adrian Tudorascu===<br />
Title: On the Lagrangian description of the Sticky Particle flow <br />
<br />
Abstract: R. Hynd has recently proved that for absolutely continuous initial velocities the Sticky Particle system admits solutions described by monotone flow maps in Lagrangian coordinates. We present a generalization of this result to general initial velocities and discuss some consequences. (This is based on ongoing work with M. Suder.)</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absS20&diff=18884Applied/ACMS/absS202020-02-04T14:39:45Z<p>Qinli: /* ACMS Abstracts: Spring 2020 */</p>
<hr />
<div>= ACMS Abstracts: Spring 2020 =<br />
<br />
=== Hung Tran ===<br />
<br />
Title: Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel<br />
<br />
Abstract: We study a critical case of Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel. Our method is based on the study of viscosity solutions to a new singular Hamilton-Jacobi equation, which results from applying the Bernstein transform to the original Coagulation-Fragmentation equation. Our results include wellposedness, regularity and long-time behaviors of viscosity solutions to the Hamilton-Jacobi equation in certain regimes, which have implications to wellposedness and long-time behaviors of mass-conserving solutions to the Coagulation-Fragmentation equation. Joint work with Truong-Son Van (CMU).<br />
<br />
=== Svetlana Avramov-Zamurovic ===<br />
<br />
Title: Experiments with Structured Light<br />
<br />
Abstract: Complete understanding of laser light propagation through random complex media, including theoretical models and experimental verifications, is relevant for numerous contemporary communication and sensors applications. Light radiation is the most suitable for transmitting high data rates due to its wide bandwidth, but it is significantly impacted by the state of the propagation media. To mitigate the deterioration of laser light along a propagation path, various independent characteristics of light could be manipulated, most notably: spatial coherence, intensity, wavelength, polarization, as well as the orbital angular momentum of light. Much of the research has focused on laser propagation through turbulent atmospheric conditions, but with the development of distributed sensor networks and autonomous underwater vehicles, achieving high performance data transmission in the ocean is becoming exceptionally valuable. The propagation of laser light in water is influenced by high attenuation rates caused by scattering from organic and inorganic particulates as well as change in refractive index due to temperature and salinity fluctuations. Structured light offers a tool to combat some of the mentioned deteriorations.<br />
<br />
The talk will focus on experiments with structured light propagating in maritime environment. First, the underwater communication system that uses the superposition of coherent beams carrying orbital angular momentum, will be presented. The design objective is the creation of a family of dissimilar images suitable for fast and accurate classification using only the intensity patterns imaged by a camera. Next, the measurements from the field experiments with spatially partially coherent light as well as polarization diversity, propagating at the Academy grounds, will be given. The talk emphasis will be on the physical aspects of the experiments with structured laser light, and the relationship to the data obtained.<br />
<br />
=== Vadim Gorin ===<br />
<br />
Title: Integrability of KPZ equation.<br />
<br />
Abstract: Kardar-Parisi-Zhang stochastic partial differential equation is a prototypical model for the random growth of one-dimensional interfaces. I will review how it appeared and present various exact formulas, which allow the large time asymptotic analysis of the solutions to the equation and hint on its connections to other stochastic objects.<br />
<br />
<br />
=== Curt A. Bronkhorst ===<br />
<br />
Title: Computational Prediction of Shear Banding and Deformation Twinning in Metals<br />
<br />
Abstract: The high deformation rate mechanical loading of polycrystalline metallic materials, which have ready access to plastic deformation mechanisms, generally involve an intense process of several deformation mechanisms within the material: dislocation slip (thermally activated and phonon drag dominated), recovery (annihilation and recrystallization), mechanical twinning, porosity, and shear banding depending upon the material. For this class of ductile materials, depending upon the boundary conditions imposed, there are varying degrees of porosity or adiabatic shear banding taking place at the later stages of the deformation history. Each of these two processes are as yet a significant challenge to predict accurately. This is true for both material models to represent the physical response of the material or the computational framework to represent accurately the creation of new surfaces or interfaces in a topologically independent way. Within this talk, I will present an enriched element technique to represent the adiabatic shear banding and deformation twinning process within a traditional Lagrangian finite element framework. A rate-dependent onset criterion for the initiation of a band is defined based upon a rate and temperature dependent material model. Once the bifurcation condition is met, the location and orientation of an embedded field zone is computed and inserted within a computational element. Once embedded the boundary conditions between the localized and unlocalized regions of the element are enforced and the composite sub-grid element follows a weighted average representation of both regions. Continuity in shear band growth is ensured by employing a non-local level-set technique connected to the displacement field within the finite-element solver. The material inside the band is able to be represented independent from the outside material and the thickness of the band can be assigned by any appropriate method. Dynamic recrystallization (DRX) is often observed in conjunction with adiabatic shear banding (ASB) in polycrystalline materials and is believed to be a critical softening mechanism contributing to the material instability. The recrystallized nanograins in the shear band have few dislocations compared to the material outside of the shear band. We reformulate a recently developed continuum theory of polycrystalline plasticity and include the creation of grain boundaries. While the shear-banding instability emerges because thermal heating is faster than heat dissipation, recrystallization is interpreted as an entropic effect arising from the competition between dislocation creation and grain boundary formation and is a significant softening mechanism. We show that our theory closely matches recent results in sheared 316L stainless steel. The theory thus provides a thermodynamically consistent way to systematically describe the formation of shear bands and recrystallized grains therein. The numerical tool has recently been applied to the modeling of deformation twinning in high-purity Ti which will be briefly discussed.</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=18883Applied/ACMS2020-02-04T14:38:39Z<p>Qinli: /* Spring 2020 */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li], [http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
<br />
== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 31<br />
|[https://www.math.wisc.edu/~hung/ Hung Tran] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Hung Tran (UW-Madison)| Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel]]''<br />
| Li<br />
|-<br />
| Feb 7<br />
|[https://www.usna.edu/Users/weaprcon/avramov/index.php Svetlana Avramov-Zamurovic] (United States Naval Academy)<br />
|''[[Applied/ACMS/absS20#Svetlana Avramov-Zamurovic (United States Naval Academy)|Experiments with Structured Light]]''<br />
| Stechmann<br />
|-<br />
| Feb 14<br />
|[http://math.mit.edu/~vadicgor/ Vadim Gorin] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Vadim Gorin (UW-Madison)| Integrability of KPZ equation]]''<br />
| Li<br />
|-<br />
| Feb 21<br />
|[http://www.personal.psu.edu/jzh13/ John Harlim] (Penn State University)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| Chen<br />
|-<br />
| Feb 28<br />
|[https://cims.nyu.edu/~yangq/ Qiu Yang] (NYU/UVic/NCAR)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| Chen<br />
|-<br />
| Mar 6<br />
|[https://directory.engr.wisc.edu/ep/Faculty/Bronkhorst_Curt/ Curt Bronkhorst] (UW-Madison Engineering Physics)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|Computational Prediction of Shear Banding and Deformation Twinning in Metals]]''<br />
| Smith<br />
|-<br />
| Mar 13<br />
|[http://www.columbia.edu/~ktm2132/ Kyle Mandli] (Columbia)<br />
|''[[Applied/ACMS/absS20#Kyle Mandli (Columbia)|TBA]]''<br />
| Wally<br />
|-<br />
| Mar 20<br />
|[Spring break] (Spring Break!)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 27<br />
|[http://www-personal.umich.edu/~jcsch/ John Schotland] (U Mich)<br />
|''[[Applied/ACMS/absS20#John Schotland (Michigan)|title]]''<br />
| host<br />
|-<br />
| Apr 3<br />
|[http://keaton-burns.com/ Keaton Burns] (MIT)<br />
|''[[Applied/ACMS/absS20#Keaton Burns (MIT)|title]]''<br />
| Spagnolie<br />
|-<br />
| Apr 10<br />
|[https://www.princeton.edu/~lecoanet/ Daniel Lecoanet] (Princeton)<br />
|''[[Applied/ACMS/absS20#Daniel Lecoanet (Princeton)|TBA]]''<br />
| Wally<br />
|-<br />
| Apr 17<br />
|[https://www.ornl.gov/staff-profile/hoang-tran Hoang Tran] (Oak Ridge National Laboratory)<br />
|''[[Applied/ACMS/absS20#Hoang Tran (institution)|title]]''<br />
| Tran<br />
|-<br />
| Apr 24<br />
|[https://www.pml.unc.edu/ Pedro Saenz] (UNC)<br />
|''[[Applied/ACMS/absF19#Pedro Saenz (UNC)|TBA]]''<br />
| Spagnolie<br />
|-<br />
|}<br />
<br />
== Future semesters ==<br />
<br />
<br />
<br />
<br />
----<br />
<br />
== Archived semesters ==<br />
<br />
*[[Applied/ACMS/Spring2020|Spring 2020]]<br />
*[[Applied/ACMS/Fall2019|Fall 2019]]<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=18823Applied/ACMS2020-01-29T22:14:13Z<p>Qinli: /* Spring 2020 */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li], [http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
<br />
== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 31<br />
|[https://www.math.wisc.edu/~hung/ Hung Tran] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Hung Tran (UW-Madison)| Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel]]''<br />
| Li<br />
|-<br />
| Feb 7<br />
|[https://www.usna.edu/Users/weaprcon/avramov/index.php Svetlana Avramov-Zamurovic] (United States Naval Academy)<br />
|''[[Applied/ACMS/absS20#Svetlana Avramov-Zamurovic (United States Naval Academy)|Experiments with Structured Light]]''<br />
| Stechmann<br />
|-<br />
| Feb 14<br />
|[http://math.mit.edu/~vadicgor/ Gorin Vadim] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Gorin Vadim (UW-Madison)|TBA, either random matrix or KPZ equation]]''<br />
| Li<br />
|-<br />
| Feb 21<br />
|[http://www.personal.psu.edu/jzh13/ John Harlim] (Penn State University)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| Chen<br />
|-<br />
| Feb 28<br />
|[https://cims.nyu.edu/~yangq/ Qiu Yang] (NYU/UVic/NCAR)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| Chen<br />
|-<br />
| Mar 6<br />
|[https://directory.engr.wisc.edu/ep/Faculty/Bronkhorst_Curt/ Curt Bronkhorst] (UW-Madison Engineering Physics)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|Computational Prediction of Shear Banding and Deformation Twinning in Metals]]''<br />
| Smith<br />
|-<br />
| Mar 13<br />
|[http://www.columbia.edu/~ktm2132/ Kyle Mandli] (Columbia)<br />
|''[[Applied/ACMS/absS20#Kyle Mandli (Columbia)|TBA]]''<br />
| Wally<br />
|-<br />
| Mar 20<br />
|[Spring break] (Spring Break!)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 27<br />
|[http://www-personal.umich.edu/~jcsch/ John Schotland] (U Mich)<br />
|''[[Applied/ACMS/absS20#John Schotland (Michigan)|title]]''<br />
| host<br />
|-<br />
| Apr 3<br />
|[http://keaton-burns.com/ Keaton Burns] (MIT)<br />
|''[[Applied/ACMS/absS20#Keaton Burns (MIT)|title]]''<br />
| Spagnolie<br />
|-<br />
| Apr 10<br />
|[https://www.princeton.edu/~lecoanet/ Daniel Lecoanet] (Princeton)<br />
|''[[Applied/ACMS/absS20#Daniel Lecoanet (Princeton)|TBA]]''<br />
| Wally<br />
|-<br />
| Apr 17<br />
|[https://www.ornl.gov/staff-profile/hoang-tran Hoang Tran] (Oak Ridge National Laboratory)<br />
|''[[Applied/ACMS/absS20#Hoang Tran (institution)|title]]''<br />
| Tran<br />
|-<br />
| Apr 24<br />
|[https://www.pml.unc.edu/ Pedro Saenz] (UNC)<br />
|''[[Applied/ACMS/absF19#Pedro Saenz (UNC)|TBA]]''<br />
| Spagnolie<br />
|-<br />
|}<br />
<br />
== Future semesters ==<br />
<br />
<br />
<br />
<br />
----<br />
<br />
== Archived semesters ==<br />
<br />
*[[Applied/ACMS/Spring2020|Spring 2020]]<br />
*[[Applied/ACMS/Fall2019|Fall 2019]]<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absS20&diff=18822Applied/ACMS/absS202020-01-29T22:13:51Z<p>Qinli: /* ACMS Abstracts: Spring 2020 */</p>
<hr />
<div>= ACMS Abstracts: Spring 2020 =<br />
<br />
=== Hung Tran ===<br />
<br />
Title: Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel<br />
<br />
Abstract: We study a critical case of Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel. Our method is based on the study of viscosity solutions to a new singular Hamilton-Jacobi equation, which results from applying the Bernstein transform to the original Coagulation-Fragmentation equation. Our results include wellposedness, regularity and long-time behaviors of viscosity solutions to the Hamilton-Jacobi equation in certain regimes, which have implications to wellposedness and long-time behaviors of mass-conserving solutions to the Coagulation-Fragmentation equation. Joint work with Truong-Son Van (CMU).<br />
<br />
=== Svetlana Avramov-Zamurovic ===<br />
<br />
Title: Experiments with Structured Light<br />
<br />
Abstract: Complete understanding of laser light propagation through random complex media, including theoretical models and experimental verifications, is relevant for numerous contemporary communication and sensors applications. Light radiation is the most suitable for transmitting high data rates due to its wide bandwidth, but it is significantly impacted by the state of the propagation media. To mitigate the deterioration of laser light along a propagation path, various independent characteristics of light could be manipulated, most notably: spatial coherence, intensity, wavelength, polarization, as well as the orbital angular momentum of light. Much of the research has focused on laser propagation through turbulent atmospheric conditions, but with the development of distributed sensor networks and autonomous underwater vehicles, achieving high performance data transmission in the ocean is becoming exceptionally valuable. The propagation of laser light in water is influenced by high attenuation rates caused by scattering from organic and inorganic particulates as well as change in refractive index due to temperature and salinity fluctuations. Structured light offers a tool to combat some of the mentioned deteriorations.<br />
<br />
The talk will focus on experiments with structured light propagating in maritime environment. First, the underwater communication system that uses the superposition of coherent beams carrying orbital angular momentum, will be presented. The design objective is the creation of a family of dissimilar images suitable for fast and accurate classification using only the intensity patterns imaged by a camera. Next, the measurements from the field experiments with spatially partially coherent light as well as polarization diversity, propagating at the Academy grounds, will be given. The talk emphasis will be on the physical aspects of the experiments with structured laser light, and the relationship to the data obtained.<br />
<br />
<br />
=== Curt A. Bronkhorst ===<br />
<br />
Title: Computational Prediction of Shear Banding and Deformation Twinning in Metals<br />
<br />
Abstract: The high deformation rate mechanical loading of polycrystalline metallic materials, which have ready access to plastic deformation mechanisms, generally involve an intense process of several deformation mechanisms within the material: dislocation slip (thermally activated and phonon drag dominated), recovery (annihilation and recrystallization), mechanical twinning, porosity, and shear banding depending upon the material. For this class of ductile materials, depending upon the boundary conditions imposed, there are varying degrees of porosity or adiabatic shear banding taking place at the later stages of the deformation history. Each of these two processes are as yet a significant challenge to predict accurately. This is true for both material models to represent the physical response of the material or the computational framework to represent accurately the creation of new surfaces or interfaces in a topologically independent way. Within this talk, I will present an enriched element technique to represent the adiabatic shear banding and deformation twinning process within a traditional Lagrangian finite element framework. A rate-dependent onset criterion for the initiation of a band is defined based upon a rate and temperature dependent material model. Once the bifurcation condition is met, the location and orientation of an embedded field zone is computed and inserted within a computational element. Once embedded the boundary conditions between the localized and unlocalized regions of the element are enforced and the composite sub-grid element follows a weighted average representation of both regions. Continuity in shear band growth is ensured by employing a non-local level-set technique connected to the displacement field within the finite-element solver. The material inside the band is able to be represented independent from the outside material and the thickness of the band can be assigned by any appropriate method. Dynamic recrystallization (DRX) is often observed in conjunction with adiabatic shear banding (ASB) in polycrystalline materials and is believed to be a critical softening mechanism contributing to the material instability. The recrystallized nanograins in the shear band have few dislocations compared to the material outside of the shear band. We reformulate a recently developed continuum theory of polycrystalline plasticity and include the creation of grain boundaries. While the shear-banding instability emerges because thermal heating is faster than heat dissipation, recrystallization is interpreted as an entropic effect arising from the competition between dislocation creation and grain boundary formation and is a significant softening mechanism. We show that our theory closely matches recent results in sheared 316L stainless steel. The theory thus provides a thermodynamically consistent way to systematically describe the formation of shear bands and recrystallized grains therein. The numerical tool has recently been applied to the modeling of deformation twinning in high-purity Ti which will be briefly discussed.</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absF19&diff=18470Applied/ACMS/absF192019-11-22T21:13:42Z<p>Qinli: /* ACMS Abstracts: Fall 2019 */</p>
<hr />
<div>= ACMS Abstracts: Fall 2019 =<br />
<br />
=== Leonardo Andrés Zepeda Núñez ===<br />
<br />
Title: Deep Learning for Electronic Structure Computations: A Tale of Symmetries, Locality, and Physics<br />
<br />
Abstract: Recently, the surge of interest in deep neural learning has dramatically improved image and signal processing, which has fueled breakthroughs in many domains such as drug discovery, genomics, and automatic translation. These advances have been further applied to scientific computing and, in particular, to electronic structure computations. In this case, the main objective is to directly compute the electron density, which encodes most of information of the system, thus bypassing the computationally intensive solution of the Kohn-Sham equations. However, similar to neural networks for image processing, the performance of the methods depends spectacularly on the physical and analytical intuition incorporated in the network, and on the training stage.<br />
<br />
In this talk, I will show how to build a network that respects physical symmetries and locality. I will show how to train the networks and how such properties impact the performance of the resulting network. Finally, I will present several examples for small yet realistic chemical systems.<br />
<br />
<br />
=== Daniel Floryan (UW-Madison) ===<br />
<br />
Title: Flexible Inertial Swimmers<br />
<br />
Abstract: Inertial swimmers deform their bodies and fins to push against the water and propel themselves forward. The deformation is driven partly by active musculature, and partly by passive elasticity. The interaction between elasticity and hydrodynamics confers features on the swimmers not enjoyed by their rigid friends, for example, boosts in speed when flapping at certain frequencies. We explain the salient features of flexible swimmers by drawing ideas from airfoils, vibrating beams, and flags flapping in the wind. The presence of fluid drag has important consequences. We also explore optimal arrangements of flexibility. (It turns out that nature is quite good.)<br />
<br />
<br />
=== Jianfeng Lu (Duke) ===<br />
<br />
Title: How to ``localize" the computation?<br />
<br />
It is often desirable to restrict the numerical computation to a local <br />
region to achieve best balance between accuracy and affordability in scientific computing. It is important to avoid artifacts and guarantee predictable modelling while artificial boundary conditions have to be introduced to restrict the computation. In this talk, we will discuss some recent understanding on how to achieve such local computation in the context of topological edge states and elliptic random media.<br />
<br />
<br />
=== Mitch Bushuk (GFDL/Princeton) ===<br />
<br />
Title: Arctic Sea Ice Predictability in a Changing Cryosphere<br />
<br />
Abstract: Forty years of satellite observations have documented a striking decline in the areal extent of Arctic sea ice. The loss of sea ice has impacts on the climate system, human populations, ecosystems, and natural environments across a broad range of spatial and temporal scales. These changes have motivated significant research interest in the predictability and prediction of Arctic sea ice on seasonal-to-interannual timescales. In this talk, I will address two related questions: (1) What is the inherent predictability of Arctic sea ice and what physical mechanisms underlie this predictability? and (2) How can this knowledge be leveraged to improve operational sea ice predictions? I will present findings on the relative roles of the ocean, sea ice, and atmosphere in controlling Arctic sea ice predictability. I will also present evidence for an Arctic spring predictability barrier, which may impose a sharp limit on our ability to make skillful predictions of the summer sea ice minimum. <br />
<br />
<br />
=== Qin Li (UW-Madison) ===<br />
<br />
Title: The power of randomness in scientific computing<br />
<br />
Abstract: Most numerical methods in scientific computing are deterministic. Traditionally, accuracy has been the target while the cost was not the concern. However, in this era of big data, we incline to relax the strict requirements on the accuracy to reduce numerical cost. Introducing randomness in the numerical solvers could potentially speed up the computation significantly at small sacrifice of accuracy. In this talk, I'd like to show two concrete examples how this is done: first on random sketching in experimental design, and the second on numerical homgenization, hoping the discussion can shed light on potential other applications. Joint work with Ke Chen, Jianfeng Lu, Kit Newton and Stephen Wright.<br />
<br />
<br />
=== Joel Nishimura (Arizona State) ===<br />
<br />
Title: Random graph models with fixed degree sequences: choices, consequences and irreducibility proofs for sampling<br />
<br />
Abstract: Determining which features of an empirical graph are noteworthy frequently relies upon the ability to sample random graphs with constrained properties. Since empirical graphs have distinctive degree sequences, one of the most popular random graph models is the configuration model, which produces a graph uniformly at random from the set of graphs with a fixed degree sequence. While it is commonly treated as though there is only a single configuration model, one sampled via stub-matching, there are many, depending on whether self-loops and multiedges are allowed and whether edge stubs are labeled or not. We show, these different configuration models can lead to drastically, sometimes opposite, interpretations of empirical graphs. In order to sample from these different configuration models, we review and develop the underpinnings of Markov chain Monte Carlo methods based upon double-edge swaps. We also present new results on the irreducibility of the Markov chain for graphs with self-loops, either proving irreducibility or exactly characterizing the degree sequences for which the Markov chain is reducible. This work completes the study of the irreducibility of double edge-swap Markov chains (and the related Curveball Markov chain) for all combinations of allowing self-loops, multiple self-loops and/or multiedges. <br />
<br />
<br />
=== Alex Townsend (Cornell) ===<br />
<br />
Title: Why are so many matrices and tensors of low rank in computational mathematics?<br />
<br />
Abstract: Matrices and tensors that appear in computational mathematics are so often well-approximated by low-rank objects. Since random ("average") matrices are almost surely of full rank, mathematics needs to explain the abundance of low-rank structures. We will give various methodologies that allow one to begin to understand the prevalence of compressible matrices and tensors and we hope to reveal an underlying link between disparate applications. In particular, we will show how one can connect the singular values of a matrix with displacement structure to a rational approximation problem that highlights fundamental connections between polynomial interpolation, Krylov methods, and fast Toeplitz solvers.<br />
<br />
<br />
=== Prashant G. Mehta ===<br />
<br />
Title: What is the Lagrangian for Nonlinear Filtering?<br />
<br />
Abstract: There is a certain magic involved in recasting the equations in Physics, and the algorithms in Engineering, in variational terms. The most classical of these ‘magics’ is the Lagrange’s formulation of the Newtonian mechanics. An accessible modern take on all this and more appears in the February 19, 2019 issue of The New Yorker magazine: https://www.newyorker.com/science/elements/a-different-kind-of-theory-of-everything?reload=true <br />
<br />
My talk is concerned with a variational (optimal control type) formulation of the problem of nonlinear filtering/estimation. Such formulations are referred to as duality between optimal estimation and optimal control. The first duality principle appears in the seminal (1961) paper of Kalman-Bucy, where the problem of minimum variance estimation is shown to be dual to a linear quadratic optimal control problem. <br />
<br />
In my talk, I will describe a generalization of the Kalman-Bucy duality theory to nonlinear filtering. The generalization is an exact extension, in the sense that the dual optimal control problem has the same minimum variance structure for linear and nonlinear filtering problems. Kalman-Bucy’s classical result is shown to be a special case. During the talk, I will also attempt to review other types of duality relationships that have appeared over the years for the problem of linear and nonlinear filtering. <br />
<br />
This is joint work with Jin Won Kim and Sean Meyn. The talk is based on the following papers: https://arxiv.org/pdf/1903.11195.pdf and https://arxiv.org/pdf/1904.01710.pdf.<br />
<br />
<br />
=== Jean-Luc Thiffeault ===<br />
<br />
Title: Shape matters: A Brownian swimmer in a channel<br />
<br />
Abstract: We consider a simple model of a two-dimensional microswimmer with fixed swimming speed. The direction of swimming changes according to<br />
a Brownian process, and the swimmer is interacting with boundaries. This is a standard model for a simple microswimmer, or a confined<br />
wormlike chain polymer. The shape of the swimmer determines the range of allowable values that its degrees of freedom can assume --- its<br />
configuration space. Using natural assumptions about reflection of the swimmer at boundaries, we compute the swimmer's invariant<br />
distribution across a channel consisting of two parallel walls, and the statistics of spreading in the longitudinal direction. This gives<br />
us the effective diffusion constant of the swimmer's large scale motion. When the swimmer is longer than the channel width, it cannot<br />
reverse, and we then compute the mean drift velocity of the swimmer. This model offers insight into experiments of scattering of swimmers<br />
from boundaries, and serves as an exactly-solvable baseline when comparing to more complex models. This is joint work with Hongfei Chen.<br />
<br />
=== Tan Bui (UT-Austin) ===<br />
<br />
Title: Scalable Algorithms for Data-driven Inverse and Learning Problems<br />
<br />
Abstract: Inverse problems and uncertainty quantification (UQ) are pervasive in scientific discovery and decision-making for complex, natural, engineered, and societal systems. They are perhaps the most popular mathematical approaches for enabling predictive scientific simulations that integrate observational/experimental data, simulations and/or models. Unfortunately, inverse/UQ problems for practical complex systems possess these the simultaneous challenges: the large-scale forward problem challenge, the high dimensional parameter space challenge, and the big data challenge.<br />
<br />
To address the first challenge, we have developed parallel high-order (hybridized) discontinuous Galerkin methods to discretize complex forward PDEs. <br />
To address the second challenge, we have developed various approaches from model reduction to advanced Markov chain Monte Carlo methods to effectively explore high dimensional parameter spaces to compute posterior statistics. To address the last challenge, we have developed a randomized misfit approach that uncovers the interplay between the Johnson-Lindenstrauss and the Morozov's discrepancy principle to significantly reduce the dimension of the data without compromising the quality of the inverse solutions.<br />
<br />
In this talk we selectively present scalable and rigorous approaches to tackle these challenges for PDE-governed Bayesian inverse problems. Various numerical results for simple to complex PDEs will be presented to verify our algorithms and theoretical findings. If time permits, we will present our recent work on scientific machine learning for inverse and learning problems.<br />
<br />
=== Wenxiao Pan (UW-Madison) ===<br />
<br />
Title: Mesoscale Modeling of Soft Matter<br />
<br />
Abstract: Soft matter systems, such as colloids and polymers, are characterized by an interplay of interactions and processes that span a wide range of length- and time scales. Computer simulations require modeling approaches to cover these scales. In order to access mesoscopic time- and length scales, necessary to access material properties, two numerical approaches will be discussed in this talk. The first one concerns suspension flows of arbitrary-shaped colloids. A high-order, spatially adaptive, meshless method was developed to solve the PDEs that govern hydrodynamics and fluid- solid interactions. Near-field hydrodynamic interactions between arbitrary-shaped colloids can be accurately captured without subgrid-scale lubrication models. The second approach seeks a bottom-up, coarse-grained modeling for polymers in solution. It starts from atomistic descriptions, and by proper mapping atomistic details onto a coarser representation, arrives at the mesoscale. The effect of unresolved degrees of freedom on the kinetics of polymers is accounted by the non-Markovian memory kernel. The coarse-grained variables and governing equation are directly linked to the statistics of atomistic data.<br />
<br />
=== Prerna Gera (UW-Madison) ===<br />
<br />
Title: Patchy Vesicles in Shear Flow<br />
<br />
Abstract: Multicomponent vesicles are fluid filled structure enclosed by a lipid bilayer and are composed of cholesterol that combine with saturated lipids to form energetically stable domains on the vesicle surface. The presence of different lipid species lead to varying material properties, such as bending rigidity, produce a rich variety of dynamics as seen in experiments. In the first part of the talk, a three dimensional continuum model will be presented to explore the dynamics of multicomponent vesicle. The membrane is modeled using a two-phase surface Cahn-Hilliard equation along with a level/set closest point method. The domain on the membrane is coupled with fluid surrounding the vesicle via an energy variation approach. Motivated by the results from the continuum simulations, a small amplitude asymptotic approach is used to derive a reduced order model and predict the low wave numbers breathing and trembling behavior of the membrane.<br />
<br />
<br />
=== Lin Lin (UC-Berkeley) ===<br />
<br />
Title: Quantum Linear System Solver<br />
<br />
Abstract: We are now in the "noisy intermediate-scale quantum" (NISQ) era, and Google has just declared that the "quantum supremacy" has been reached. If given a quantum computer (that works), what can a numerical analyst do? This talk discusses some recent progresses on quantum algorithms for solving linear systems. In particular, with an optimally tuned scheduling function, adiabatic quantum computing (AQC) can solve a quantum linear system problem with $\mathcal(\kappa/\epsilon)$ runtime, where $\kappa$ is the condition number, and $\epsilon$ is the target accuracy. No prior knowledge on quantum computing is needed.<br />
<br />
References:<br />
<br />
D. An and L. Lin, Quantum linear system solver based on time-optimal adiabatic quantum computing and quantum approximate optimization algorithm [arXiv:1909.05500]<br />
<br />
L. Lin and Y. Tong, Solving quantum linear system problem with near-optimal complexity [arXiv:1910.14596]</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=18469Applied/ACMS2019-11-22T21:12:42Z<p>Qinli: /* Fall 2019 */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li], [http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
<br />
== Fall 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Sept 6<br />
|[http://math.mit.edu/~lzepeda/ Leonardo Andrés Zepeda Núñez] (UW-Madison)<br />
|''[[Applied/ACMS/absF19#Leonardo Andrés Zepeda Núñez (UW-Madison)|Deep Learning for Electronic Structure Computations: A Tale of Symmetries, Locality, and Physics]]''<br />
| Li<br />
|-<br />
| Sept 13<br />
|[http://dfloryan.mycpanel.princeton.edu/ Daniel Floryan] (UW-Madison)<br />
|''[[Applied/ACMS/absF19#Daniel Floryan (UW-Madison)|Flexible Inertial Swimmers]]''<br />
| Jean-Luc<br />
|-<br />
| Sept 14-15<br />
|[https://www.ams.org/meetings/sectional/2267_program.html AMS sectional meeting]<br />
| UW-Madison<br />
|-<br />
| Sept 20<br />
|[https://www.gfdl.noaa.gov/mitch-bushuk/ Mitch Bushuk] (GFDL/Princeton)<br />
|''[[Applied/ACMS/absF19#Mitch Bushuk (GFDL/Princeton)|Arctic Sea Ice Predictability in a Changing Cryosphere]]''<br />
| Chen<br />
|-<br />
| Sept 20 (colloquium, 4pm, B239)<br />
|[https://services.math.duke.edu/~jianfeng/ Jianfeng Lu] (Duke)<br />
|''[[Applied/ACMS/absF19#Jianfeng Lu (Duke)|How to "localize" the computation?]]''<br />
| Li<br />
|-<br />
| Sept 27<br />
|[http://www.math.wisc.edu/~qinli/ Qin Li] (UW-Madison)<br />
|''[[Applied/ACMS/absF19#Qin Li (UW-Madison)|The power of randomness in scientific computing]]''<br />
| host<br />
|-<br />
| Oct 4<br />
|[https://isearch.asu.edu/profile/2169104 Joel Nishimura] (Arizona State)<br />
|''[[Applied/ACMS/absF19#Joel Nishimura (Arizona State)|Random graph models with fixed degree sequences: choices, consequences and irreducibility proofs for sampling]]''<br />
| Cochran<br />
|-<br />
| Oct 11<br />
|[http://pi.math.cornell.edu/~ajt/ Alex Townsend] (Cornell)<br />
|''[[Applied/ACMS/absF19#Alex Townsend (Cornell)|Why are so many matrices and tensors of low rank in computational mathematics?]]''<br />
| Li<br />
|-<br />
| Oct 18<br />
|[http://mehta.mechse.illinois.edu/ Prashant G. Mehta] (UIUC)<br />
|''[[Applied/ACMS/absF19#Prashant G. Mehta (UIUC)|What is the Lagrangian for Nonlinear Filtering?]]''<br />
| Chen<br />
|-<br />
| Oct 25<br />
|[https://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault] (UW-Madison)<br />
|''[[Applied/ACMS/absF19#Jean-Luc Thiffeault|Shape matters: A Brownian microswimmer interacting with walls]]''<br />
| <br />
|-<br />
| Nov 1<br />
|[https://users.oden.utexas.edu/~tanbui/ Tan Bui] (UT-Austin)<br />
|''[[Applied/ACMS/absF19#Tan Bui (UT-Austin)|Scalable Algorithms for Data-driven Inverse and Learning Problems]]''<br />
| Li<br />
|-<br />
| Nov 8<br />
|[https://pan.labs.wisc.edu/staff/pan-wenxiao/ Wenxiao Pan] (UW)<br />
|''[[Applied/ACMS/absF19#Wenxiao Pan (UW)|Mesoscale Modeling of Soft Matter]]''<br />
| Spagnolie<br />
| <br />
|-<br />
| Nov 15<br />
|[https://www.math.wisc.edu/~pgera/ Prerna Gera] (UW)<br />
|''[[Applied/ACMS/absF19#Prerna Gera (UW)|Patchy Vesicles in Shear Flow]]''<br />
| Spagnolie<br />
|-<br />
| Dec 6<br />
|[https://math.berkeley.edu/~linlin/ Lin Lin] (Berkeley)<br />
|''[[Applied/ACMS/absF19#Lin Lin (UC Berkeley)|Quantum Linear System Solver]]''<br />
| Li<br />
|-<br />
|}<br />
<br />
== Future semesters ==<br />
<br />
*[[Applied/ACMS/Spring2020|Spring 2020]]<br />
<br />
== Archived semesters ==<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/Spring2020&diff=18463Applied/ACMS/Spring20202019-11-21T23:19:48Z<p>Qinli: /* Spring 2020 */</p>
<hr />
<div>== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 31<br />
|[https://www.math.wisc.edu/~hung/ Hung Tran] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Hung Tran (UW-Madison)| Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel]]''<br />
| Li<br />
|-<br />
| Feb 7<br />
|[https://www.usna.edu/Users/weaprcon/avramov/index.php Svetlana Avramov-Zamurovic] (United States Naval Academy)<br />
|''[[Applied/ACMS/absS20#Svetlana Avramov-Zamurovic (United States Naval Academy)|TBA]]''<br />
| Stechmann<br />
|-<br />
| Feb 14<br />
|[http://math.mit.edu/~vadicgor/ Gorin Vadim] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Gorin Vadim (UW-Madison)|TBA, either random matrix or KPZ equation]]''<br />
| Li<br />
|-<br />
| Feb 21<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Feb 28<br />
|[https://cims.nyu.edu/~yangq/ Qiu Yang] (NYU/UVic/NCAR)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| Chen<br />
|-<br />
| Mar 6<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 13<br />
|[http://www.columbia.edu/~ktm2132/ Kyle Mandli] (Columbia)<br />
|''[[Applied/ACMS/absS20#Kyle Mandli (Columbia)|TBA]]''<br />
| Wally<br />
|-<br />
| Mar 20<br />
|[Spring break] (Spring Break!)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 27<br />
|[http://www-personal.umich.edu/~jcsch/ John Schotland] (U Mich)<br />
|''[[Applied/ACMS/absS20#John Schotland (Michigan)|title]]''<br />
| host<br />
|-<br />
| Apr 3<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 10<br />
|[https://www.princeton.edu/~lecoanet/ Daniel Lecoanet] (Princeton)<br />
|''[[Applied/ACMS/absS20#Daniel Lecoanet (Princeton)|TBA]]''<br />
| Wally<br />
|-<br />
| Apr 17<br />
|[https://www.ornl.gov/staff-profile/hoang-tran Hoang Tran] (Oak Ridge National Laboratory)<br />
|''[[Applied/ACMS/absS20#Hoang Tran (institution)|title]]''<br />
| Tran<br />
|-<br />
| Apr 24<br />
|[https://www.pml.unc.edu/ Pedro Saenz] (UNC)<br />
|''[[Applied/ACMS/absF19#Pedro Saenz (UNC)|TBA]]''<br />
| Spagnolie</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/Spring2020&diff=18462Applied/ACMS/Spring20202019-11-21T23:19:04Z<p>Qinli: /* Spring 2020 */</p>
<hr />
<div>== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 31<br />
|[https://www.math.wisc.edu/~hung/ Hung Tran] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Hung Tran (UW-Madison)| Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel]]''<br />
| Li<br />
|-<br />
| Feb 7<br />
|[https://www.usna.edu/Users/weaprcon/avramov/index.php Svetlana Avramov-Zamurovic] (United States Naval Academy)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Feb 14<br />
|[http://math.mit.edu/~vadicgor/ Gorin Vadim] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Gorin Vadim (UW-Madison)|TBA, either random matrix or KPZ equation]]''<br />
| Li<br />
|-<br />
| Feb 21<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Feb 28<br />
|[https://cims.nyu.edu/~yangq/ Qiu Yang] (NYU/UVic/NCAR)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| Chen<br />
|-<br />
| Mar 6<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 13<br />
|[http://www.columbia.edu/~ktm2132/ Kyle Mandli] (Columbia)<br />
|''[[Applied/ACMS/absS20#Kyle Mandli (Columbia)|TBA]]''<br />
| Wally<br />
|-<br />
| Mar 20<br />
|[Spring break] (Spring Break!)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 27<br />
|[http://www-personal.umich.edu/~jcsch/ John Schotland] (U Mich)<br />
|''[[Applied/ACMS/absS20#John Schotland (Michigan)|title]]''<br />
| host<br />
|-<br />
| Apr 3<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 10<br />
|[https://www.princeton.edu/~lecoanet/ Daniel Lecoanet] (Princeton)<br />
|''[[Applied/ACMS/absS20#Daniel Lecoanet (Princeton)|TBA]]''<br />
| Wally<br />
|-<br />
| Apr 17<br />
|[https://www.ornl.gov/staff-profile/hoang-tran Hoang Tran] (Oak Ridge National Laboratory)<br />
|''[[Applied/ACMS/absS20#Hoang Tran (institution)|title]]''<br />
| Tran<br />
|-<br />
| Apr 24<br />
|[https://www.pml.unc.edu/ Pedro Saenz] (UNC)<br />
|''[[Applied/ACMS/absF19#Pedro Saenz (UNC)|TBA]]''<br />
| Spagnolie</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/Spring2020&diff=18451Applied/ACMS/Spring20202019-11-18T21:16:47Z<p>Qinli: /* Spring 2020 */</p>
<hr />
<div>== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 31<br />
|[https://www.math.wisc.edu/~hung/ Hung Tran] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Hung Tran (UW-Madison)| Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel]]''<br />
| Li<br />
|-<br />
| Feb 7<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Feb 14<br />
|[http://math.mit.edu/~vadicgor/ Gorin Vadim] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Gorin Vadim (UW-Madison)|TBA, either random matrix or KPZ equation]]''<br />
| Li<br />
|-<br />
| Feb 21<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Feb 28<br />
|[https://cims.nyu.edu/~yangq/ Qiu Yang] (NYU/UVic/NCAR)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| Chen<br />
|-<br />
| Mar 6<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 13<br />
|[http://www.columbia.edu/~ktm2132/ Kyle Mandli] (Columbia)<br />
|''[[Applied/ACMS/absS20#Kyle Mandli (Columbia)|TBA]]''<br />
| Wally<br />
|-<br />
| Mar 20<br />
|[Spring break] (Spring Break!)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 27<br />
|[http://www-personal.umich.edu/~jcsch/ John Schotland] (U Mich)<br />
|''[[Applied/ACMS/absS20#John Schotland (Michigan)|title]]''<br />
| host<br />
|-<br />
| Apr 3<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 10<br />
|[https://www.princeton.edu/~lecoanet/ Daniel Lecoanet] (Princeton)<br />
|''[[Applied/ACMS/absS20#Daniel Lecoanet (Princeton)|TBA]]''<br />
| Wally<br />
|-<br />
| Apr 17<br />
|[https://www.ornl.gov/staff-profile/hoang-tran Hoang Tran] (Oak Ridge National Laboratory)<br />
|''[[Applied/ACMS/absS20#Hoang Tran (institution)|title]]''<br />
| Tran<br />
|-<br />
| Apr 24<br />
|[https://www.pml.unc.edu/ Pedro Saenz] (UNC)<br />
|''[[Applied/ACMS/absF19#Pedro Saenz (UNC)|TBA]]''<br />
| Spagnolie</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/Spring2020&diff=18450Applied/ACMS/Spring20202019-11-18T20:18:51Z<p>Qinli: /* Spring 2020 */</p>
<hr />
<div>== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 31<br />
|[https://www.math.wisc.edu/~hung/ Hung Tran] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Hung Tran (UW-Madison)| Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel]]''<br />
| Li<br />
|-<br />
| Feb 7<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Feb 14<br />
|[http://math.mit.edu/~vadicgor/ Gorin Vadim] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Gorin Vadim (UW-Madison)|TBA, either random matrix or KPZ equation]]''<br />
| Li<br />
|-<br />
| Feb 21<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Feb 28<br />
|[https://cims.nyu.edu/~yangq/ Qiu Yang] (NYU/UVic/NCAR)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| Chen<br />
|-<br />
| Mar 6<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 13<br />
|[http://www.columbia.edu/~ktm2132/ Kyle Mandli] (Columbia)<br />
|''[[Applied/ACMS/absS20#Kyle Mandli (Columbia)|TBA]]''<br />
| Wally<br />
|-<br />
| Mar 20<br />
|[Spring break] (Spring Break!)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 27<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 3<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 10<br />
|[https://www.princeton.edu/~lecoanet/ Daniel Lecoanet] (Princeton)<br />
|''[[Applied/ACMS/absS20#Daniel Lecoanet (Princeton)|TBA]]''<br />
| Wally<br />
|-<br />
| Apr 17<br />
|[https://www.ornl.gov/staff-profile/hoang-tran Hoang Tran] (Oak Ridge National Laboratory)<br />
|''[[Applied/ACMS/absS20#Hoang Tran (institution)|title]]''<br />
| Tran<br />
|-<br />
| Apr 24<br />
|[https://www.pml.unc.edu/ Pedro Saenz] (UNC)<br />
|''[[Applied/ACMS/absF19#Pedro Saenz (UNC)|TBA]]''<br />
| Spagnolie</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/Spring2020&diff=18402Applied/ACMS/Spring20202019-11-12T14:50:59Z<p>Qinli: /* Spring 2020 */</p>
<hr />
<div>== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 31<br />
|[https://www.math.wisc.edu/~hung/ Hung Tran] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Hung Tran (UW-Madison)| Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel]]''<br />
| Li<br />
|-<br />
| Feb 7<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Feb 14<br />
|[http://math.mit.edu/~vadicgor/ Gorin Vadim] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Gorin Vadim (UW-Madison)|TBA, either random matrix or KPZ equation]]''<br />
| Li<br />
|-<br />
| Feb 21<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Feb 28<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 6<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 13<br />
|[http://www.columbia.edu/~ktm2132/ Kyle Mandli] (Columbia)<br />
|''[[Applied/ACMS/absS20#Kyle Mandli (Columbia)|TBA]]''<br />
| Wally<br />
|-<br />
| Mar 20<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 27<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 3<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 10<br />
|[https://www.princeton.edu/~lecoanet/ Daniel Lecoanet] (Princeton)<br />
|''[[Applied/ACMS/absS20#Daniel Lecoanet (Princeton)|TBA]]''<br />
| Wally<br />
|-<br />
| Apr 17<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 24<br />
|[https://www.pml.unc.edu/ Pedro Saenz] (UNC)<br />
|''[[Applied/ACMS/absF19#Pedro Saenz (UNC)|TBA]]''<br />
| Spagnolie</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/Spring2020&diff=18338Applied/ACMS/Spring20202019-11-06T20:18:41Z<p>Qinli: /* Spring 2020 */</p>
<hr />
<div>== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 31<br />
|[https://www.math.wisc.edu/~hung/ Hung Tran] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Hung Tran (UW-Madison)| Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel]]''<br />
| Li<br />
|-<br />
| Feb 7<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Feb 14<br />
|[http://math.mit.edu/~vadicgor/ Gorin Vadim] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Gorin Vadim (UW-Madison)|TBA, either random matrix or KPZ equation]]''<br />
| host<br />
|-<br />
| Feb 21<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Feb 28<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 6<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 13<br />
|[http://www.columbia.edu/~ktm2132/ Kyle Mandli] (Columbia)<br />
|''[[Applied/ACMS/absS20#Kyle Mandli (Columbia)|TBA]]''<br />
| host<br />
|-<br />
| Mar 20<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 27<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 3<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 10<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 17<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 24<br />
|[https://www.pml.unc.edu/ Pedro Saenz] (UNC)<br />
|''[[Applied/ACMS/absF19#Pedro Saenz (UNC)|TBA]]''<br />
| Spagnolie</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Colloquia/Fall_2020&diff=18335Colloquia/Fall 20202019-11-06T03:01:51Z<p>Qinli: </p>
<hr />
<div>{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
|Sept 18<br />
| [https://users.oden.utexas.edu/~pgm/ Per-Gunnar Martinsson] (UT-Austin)<br />
| [[#Per-Gunnar Martinsson (UT-Austin) | TBA ]]<br />
| Li<br />
|-<br />
|Sept 25<br />
| [webpage name] (institute)<br />
|[[#name (institute)| Title ]]<br />
| host</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Colloquia/Fall_2020&diff=18334Colloquia/Fall 20202019-11-06T03:00:57Z<p>Qinli: Created page with "{| cellpadding="8" !align="left" | date !align="left" | speaker !align="left" | title !align="left" | host(s) |- |Sept 19 | [https://users.oden.utexas.edu/~pgm/ Per-Gunnar..."</p>
<hr />
<div>{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
|Sept 19<br />
| [https://users.oden.utexas.edu/~pgm/ Per-Gunnar Martinsson] (UT-Austin)<br />
| [[#Per-Gunnar Martinsson (UT-Austin) | TBA ]]<br />
| Li<br />
|-<br />
|Sept 26<br />
| [webpage name] (institute)<br />
|[[#name (institute)| Title ]]<br />
| host</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Colloquia/Spring2020&diff=18333Colloquia/Spring20202019-11-06T02:58:07Z<p>Qinli: /* Future Colloquia */</p>
<hr />
<div>= Mathematics Colloquium =<br />
<br />
All colloquia are on Fridays at 4:00 pm in Van Vleck B239, '''unless otherwise indicated'''.<br />
<br />
<br />
<br />
==Fall 2019==<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
|Sept 6 '''Room 911'''<br />
| Will Sawin (Columbia)<br />
| [[#Will Sawin (Columbia) | On Chowla's Conjecture over F_q[T] ]]<br />
| Marshall<br />
|-<br />
|Sept 13<br />
| [https://www.math.ksu.edu/~soibel/ Yan Soibelman] (Kansas State)<br />
|[[#Yan Soibelman (Kansas State)| Riemann-Hilbert correspondence and Fukaya categories ]]<br />
| Caldararu<br />
|<br />
|-<br />
|Sept 16 '''Monday Room 911'''<br />
| [http://mate.dm.uba.ar/~alidick/ Alicia Dickenstein] (Buenos Aires)<br />
|[[#Alicia Dickenstein (Buenos Aires)| Algebra and geometry in the study of enzymatic cascades ]]<br />
| Craciun<br />
|<br />
|-<br />
|Sept 20<br />
| [https://math.duke.edu/~jianfeng/ Jianfeng Lu] (Duke)<br />
|[[#Jianfeng Lu (Duke) | How to "localize" the computation?]]<br />
| Qin<br />
|<br />
|-<br />
|Sept 26 '''Thursday 3-4 pm Room 911'''<br />
| [http://eugeniacheng.com/ Eugenia Cheng] (School of the Art Institute of Chicago)<br />
| [[#Eugenia Cheng (School of the Art Institute of Chicago)| Character vs gender in mathematics and beyond ]]<br />
| Marshall / Friends of UW Madison Libraries<br />
|<br />
|-<br />
|Sept 27<br />
|<br />
|<br />
|-<br />
|Oct 4<br />
|<br />
|<br />
|-<br />
|Oct 11<br />
| Omer Mermelstein (Madison)<br />
| [[#Omer Mermelstein (Madison)| Generic flat pregeometries ]]<br />
|Andrews<br />
|<br />
|-<br />
|Oct 18<br />
| Shamgar Gurevich (Madison)<br />
| [[#Shamgar Gurevich (Madison) | Harmonic Analysis on GL(n) over Finite Fields ]]<br />
| Marshall<br />
|-<br />
|Oct 25<br />
|<br />
|-<br />
|Nov 1<br />
|Elchanan Mossel (MIT)<br />
|Distinguished Lecture<br />
|Roch<br />
|-<br />
|Nov 8<br />
|Jose Rodriguez (UW-Madison)<br />
|[[#Jose Rodriguez (UW-Madison) | Nearest Point Problems and Euclidean Distance Degrees]]<br />
|Erman<br />
|-<br />
|Nov 15<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Nov 22<br />
| Jeffrey Danciger (UT Austin)<br />
| [[#Jeffrey Danciger (UT Austin) | "TBA"]]<br />
| Kent<br />
|-<br />
|Nov 29<br />
|Thanksgiving<br />
|<br />
|-<br />
|Dec 6<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Dec 11 '''Wednesday'''<br />
|Nick Higham (Manchester)<br />
|LAA lecture<br />
|Brualdi<br />
|<br />
|-<br />
|Dec 13<br />
|Reserved for job talk<br />
|<br />
|}<br />
<br />
==Spring 2020==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|<br />
|-<br />
|Jan 24<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Jan 31<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Feb 7<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Feb 14<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Feb 21<br />
|Shai Evra (IAS)<br />
|<br />
|Gurevich<br />
|<br />
|-<br />
|Feb 28<br />
|Brett Wick (Washington University, St. Louis)<br />
|<br />
|Seeger<br />
|-<br />
|March 6<br />
| Jessica Fintzen (Michigan)<br />
|<br />
|Marshall<br />
|-<br />
|March 13<br />
|<br />
|-<br />
|March 20<br />
|Spring break<br />
|<br />
|-<br />
|March 27<br />
|(Moduli Spaces Conference)<br />
|<br />
|Boggess, Sankar<br />
|-<br />
|April 3<br />
|Caroline Turnage-Butterbaugh (Carleton College)<br />
|<br />
|Marshall<br />
|-<br />
|April 10<br />
| Sarah Koch (Michigan)<br />
|<br />
| Bruce (WIMAW)<br />
|-<br />
|April 17<br />
|Song Sun (Berkeley)<br />
|<br />
|Huang<br />
|-<br />
|April 24<br />
|Natasa Sesum (Rutgers University)<br />
|<br />
|Angenent<br />
|-<br />
|May 1<br />
|Robert Lazarsfeld (Stony Brook)<br />
|Distinguished lecture<br />
|Erman<br />
|}<br />
<br />
== Abstracts ==<br />
<br />
<br />
===Will Sawin (Columbia)===<br />
<br />
Title: On Chowla's Conjecture over F_q[T]<br />
<br />
Abstract: The Mobius function in number theory is a sequences of 1s, <br />
-1s, and 0s, which is simple to define and closely related to the <br />
prime numbers. Its behavior seems highly random. Chowla's conjecture <br />
is one precise formalization of this randomness, and has seen recent <br />
work by Matomaki, Radziwill, Tao, and Teravainen making progress on <br />
it. In joint work with Mark Shusterman, we modify this conjecture by <br />
replacing the natural numbers parameterizing this sequence with <br />
polynomials over a finite field. Under mild conditions on the finite <br />
field, we are able to prove a strong form of this conjecture. The <br />
proof is based on taking a geometric perspective on the problem, and <br />
succeeds because we are able to simplify the geometry using a trick <br />
based on the strange properties of polynomial derivatives over finite <br />
fields.<br />
<br />
<br />
===Yan Soibelman (Kansas State)===<br />
<br />
Title: Riemann-Hilbert correspondence and Fukaya categories<br />
<br />
Abstract: In this talk I am going to discuss the role of Fukaya categories in the Riemann-Hilbert correspondence<br />
for differential, q-difference and elliptic difference equations in dimension one.<br />
This approach not only gives a unified answer for several versions of the Riemann-Hilbert correspondence but also leads to a natural formulation<br />
of the non-abelian Hodge theory in dimension one. It also explains why periodic monopoles<br />
should appear as harmonic objects in this generalized non-abelian Hodge theory.<br />
All that is a part of the bigger project ``Holomorphic Floer theory",<br />
joint with Maxim Kontsevich.<br />
<br />
<br />
===Alicia Dickenstein (Buenos Aires)===<br />
<br />
Title: Algebra and geometry in the study of enzymatic cascades<br />
<br />
Abstract: In recent years, techniques from computational and real algebraic geometry have been successfully used to address mathematical challenges in systems biology. The algebraic theory of chemical reaction systems aims to understand their dynamic behavior by taking advantage of the inherent algebraic structure in the kinetic equations, and does not need the determination of the parameters a priori, which can be theoretically or practically impossible.<br />
I will give a gentle introduction to general results based on the network structure. In particular, I will describe a general framework for biological systems, called MESSI systems, that describe Modifications of type Enzyme-Substrate or Swap with Intermediates, and include many networks that model post-translational modifications of proteins inside the cell. I will also outline recent methods to address the important question of multistationarity, in particular in the study of enzymatic cascades, and will point out some of the mathematical challenges that arise from this application.<br />
<br />
<br />
=== Jianfeng Lu (Duke) ===<br />
Title: How to ``localize" the computation?<br />
<br />
It is often desirable to restrict the numerical computation to a local region to achieve best balance between accuracy and affordability in scientific computing. It is important to avoid artifacts and guarantee predictable modelling while artificial boundary conditions have to be introduced to restrict the computation. In this talk, we will discuss some recent understanding on how to achieve such local computation in the context of topological edge states and elliptic random media.<br />
<br />
===Eugenia Cheng (School of the Art Institute of Chicago)===<br />
<br />
Title: Character vs gender in mathematics and beyond<br />
<br />
Abstract: This presentation will be based on my experience of being a female mathematician, and teaching mathematics at all levels from elementary school to grad school. The question of why women are under-represented in mathematics is complex and there are no simple answers, only many many contributing factors. I will focus on character traits, and argue that if we focus on this rather than gender we can have a more productive and less divisive conversation. To try and focus on characters rather than genders I will introduce gender-neutral character adjectives "ingressive" and "congressive" to replace masculine and feminine. I will share my experience of teaching congressive abstract mathematics to art students, in a congressive way, and the possible effects this could have for everyone in mathematics, not just women.<br />
<br />
===Omer Mermelstein (Madison)===<br />
<br />
Title: Generic flat pregeometries<br />
<br />
Abstract: In model theory, the tamest of structures are the strongly minimal ones -- those in which every equation in a single variable has either finitely many or cofinitely many solution. Algebraically closed fields and vector spaces are the canonical examples. Zilber’s conjecture, later refuted by Hrushovski, states that the source of geometric complexity in a strongly minimal structure must be algebraic. The property of "flatness" (strict gammoid) of a geometry (matroid) is that which guarantees Hrushovski's construction is devoid of any associative structure.<br />
The majority of the talk will explain what flatness is, how it should be thought of, and how closely it relates to hypergraphs and Hrushovski's construction method. Model theory makes an appearance only in the second part, where I will share results pertaining to the specific family of geometries arising from Hrushovski's methods.<br />
<br />
<br />
===Shamgar Gurevich (Madison)===<br />
<br />
Title: Harmonic Analysis on GL(n) over Finite Fields.<br />
<br />
Abstract: There are many formulas that express interesting properties of a finite group G in terms of sums over its characters. For evaluating or estimating these sums, one of the most salient quantities to understand is the character ratio:<br />
<br />
trace(ρ(g)) / dim(ρ),<br />
<br />
for an irreducible representation ρ of G and an element g of G. For example, Diaconis and Shahshahani stated a formula of the mentioned type for analyzing certain random walks on G.<br />
<br />
Recently, we discovered that for classical groups G over finite fields there is a natural invariant of representations that provides strong information on the character ratio. We call this invariant rank. <br />
<br />
This talk will discuss the notion of rank for the group GLn over finite fields, demonstrate how it controls the character ratio, and explain how one can apply the results to verify mixing time and rate for certain random walks.<br />
<br />
This is joint work with Roger Howe (Yale and Texas AM). The numerics for this work was carried by Steve Goldstein (Madison)<br />
<br />
<br />
===Jose Rodriguez (UW-Madison)===<br />
Determining the closest point to a model (subset of Euclidean space) is an important problem in many applications in science,<br />
engineering, and statistics. One way to solve this problem is by minimizing the squared Euclidean distance function using a gradient<br />
descent approach. However, when there are multiple local minima, there is no guarantee of convergence to the true global minimizer.<br />
An alternative method is to determine the critical points of an objective function on the model.<br />
In algebraic statistics, the models of interest are algebraic sets, i.e., solution sets to a system of multivariate polynomial equations. In this situation, the number of critical points of the squared Euclidean distance function on the model’s Zariski closure is a topological invariant called the Euclidean distance degree (ED degree).<br />
In this talk, I will present some models from computer vision and statistics that may be described as algebraic sets. Moreover,<br />
I will describe a topological method for determining a Euclidean distance degree and a numerical algebraic geometry approach for<br />
determining critical points of the squared Euclidean distance function.<br />
<br />
=== Jeffrey Danciger (UT Austin) ===<br />
<br />
Title: TBA<br />
<br />
== Future Colloquia ==<br />
[[Colloquia/Fall 2020| Fall 2020]]<br />
<br />
== Past Colloquia ==<br />
<br />
[[Colloquia/Blank|Blank]]<br />
<br />
[[Colloquia/Spring2019|Spring 2019]]<br />
<br />
[[Colloquia/Fall2018|Fall 2018]]<br />
<br />
[[Colloquia/Spring2018|Spring 2018]]<br />
<br />
[[Colloquia/Fall2017|Fall 2017]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
<br />
[[Colloquia 2012-2013|Spring 2013]]<br />
<br />
[[Colloquia 2012-2013#Fall 2012|Fall 2012]]</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Colloquia/Spring2020&diff=18332Colloquia/Spring20202019-11-06T02:57:45Z<p>Qinli: /* Mathematics Colloquium */</p>
<hr />
<div>= Mathematics Colloquium =<br />
<br />
All colloquia are on Fridays at 4:00 pm in Van Vleck B239, '''unless otherwise indicated'''.<br />
<br />
<br />
<br />
==Fall 2019==<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
|Sept 6 '''Room 911'''<br />
| Will Sawin (Columbia)<br />
| [[#Will Sawin (Columbia) | On Chowla's Conjecture over F_q[T] ]]<br />
| Marshall<br />
|-<br />
|Sept 13<br />
| [https://www.math.ksu.edu/~soibel/ Yan Soibelman] (Kansas State)<br />
|[[#Yan Soibelman (Kansas State)| Riemann-Hilbert correspondence and Fukaya categories ]]<br />
| Caldararu<br />
|<br />
|-<br />
|Sept 16 '''Monday Room 911'''<br />
| [http://mate.dm.uba.ar/~alidick/ Alicia Dickenstein] (Buenos Aires)<br />
|[[#Alicia Dickenstein (Buenos Aires)| Algebra and geometry in the study of enzymatic cascades ]]<br />
| Craciun<br />
|<br />
|-<br />
|Sept 20<br />
| [https://math.duke.edu/~jianfeng/ Jianfeng Lu] (Duke)<br />
|[[#Jianfeng Lu (Duke) | How to "localize" the computation?]]<br />
| Qin<br />
|<br />
|-<br />
|Sept 26 '''Thursday 3-4 pm Room 911'''<br />
| [http://eugeniacheng.com/ Eugenia Cheng] (School of the Art Institute of Chicago)<br />
| [[#Eugenia Cheng (School of the Art Institute of Chicago)| Character vs gender in mathematics and beyond ]]<br />
| Marshall / Friends of UW Madison Libraries<br />
|<br />
|-<br />
|Sept 27<br />
|<br />
|<br />
|-<br />
|Oct 4<br />
|<br />
|<br />
|-<br />
|Oct 11<br />
| Omer Mermelstein (Madison)<br />
| [[#Omer Mermelstein (Madison)| Generic flat pregeometries ]]<br />
|Andrews<br />
|<br />
|-<br />
|Oct 18<br />
| Shamgar Gurevich (Madison)<br />
| [[#Shamgar Gurevich (Madison) | Harmonic Analysis on GL(n) over Finite Fields ]]<br />
| Marshall<br />
|-<br />
|Oct 25<br />
|<br />
|-<br />
|Nov 1<br />
|Elchanan Mossel (MIT)<br />
|Distinguished Lecture<br />
|Roch<br />
|-<br />
|Nov 8<br />
|Jose Rodriguez (UW-Madison)<br />
|[[#Jose Rodriguez (UW-Madison) | Nearest Point Problems and Euclidean Distance Degrees]]<br />
|Erman<br />
|-<br />
|Nov 15<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Nov 22<br />
| Jeffrey Danciger (UT Austin)<br />
| [[#Jeffrey Danciger (UT Austin) | "TBA"]]<br />
| Kent<br />
|-<br />
|Nov 29<br />
|Thanksgiving<br />
|<br />
|-<br />
|Dec 6<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Dec 11 '''Wednesday'''<br />
|Nick Higham (Manchester)<br />
|LAA lecture<br />
|Brualdi<br />
|<br />
|-<br />
|Dec 13<br />
|Reserved for job talk<br />
|<br />
|}<br />
<br />
==Spring 2020==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|<br />
|-<br />
|Jan 24<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Jan 31<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Feb 7<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Feb 14<br />
|Reserved for job talk<br />
|<br />
|-<br />
|Feb 21<br />
|Shai Evra (IAS)<br />
|<br />
|Gurevich<br />
|<br />
|-<br />
|Feb 28<br />
|Brett Wick (Washington University, St. Louis)<br />
|<br />
|Seeger<br />
|-<br />
|March 6<br />
| Jessica Fintzen (Michigan)<br />
|<br />
|Marshall<br />
|-<br />
|March 13<br />
|<br />
|-<br />
|March 20<br />
|Spring break<br />
|<br />
|-<br />
|March 27<br />
|(Moduli Spaces Conference)<br />
|<br />
|Boggess, Sankar<br />
|-<br />
|April 3<br />
|Caroline Turnage-Butterbaugh (Carleton College)<br />
|<br />
|Marshall<br />
|-<br />
|April 10<br />
| Sarah Koch (Michigan)<br />
|<br />
| Bruce (WIMAW)<br />
|-<br />
|April 17<br />
|Song Sun (Berkeley)<br />
|<br />
|Huang<br />
|-<br />
|April 24<br />
|Natasa Sesum (Rutgers University)<br />
|<br />
|Angenent<br />
|-<br />
|May 1<br />
|Robert Lazarsfeld (Stony Brook)<br />
|Distinguished lecture<br />
|Erman<br />
|}<br />
<br />
== Abstracts ==<br />
<br />
<br />
===Will Sawin (Columbia)===<br />
<br />
Title: On Chowla's Conjecture over F_q[T]<br />
<br />
Abstract: The Mobius function in number theory is a sequences of 1s, <br />
-1s, and 0s, which is simple to define and closely related to the <br />
prime numbers. Its behavior seems highly random. Chowla's conjecture <br />
is one precise formalization of this randomness, and has seen recent <br />
work by Matomaki, Radziwill, Tao, and Teravainen making progress on <br />
it. In joint work with Mark Shusterman, we modify this conjecture by <br />
replacing the natural numbers parameterizing this sequence with <br />
polynomials over a finite field. Under mild conditions on the finite <br />
field, we are able to prove a strong form of this conjecture. The <br />
proof is based on taking a geometric perspective on the problem, and <br />
succeeds because we are able to simplify the geometry using a trick <br />
based on the strange properties of polynomial derivatives over finite <br />
fields.<br />
<br />
<br />
===Yan Soibelman (Kansas State)===<br />
<br />
Title: Riemann-Hilbert correspondence and Fukaya categories<br />
<br />
Abstract: In this talk I am going to discuss the role of Fukaya categories in the Riemann-Hilbert correspondence<br />
for differential, q-difference and elliptic difference equations in dimension one.<br />
This approach not only gives a unified answer for several versions of the Riemann-Hilbert correspondence but also leads to a natural formulation<br />
of the non-abelian Hodge theory in dimension one. It also explains why periodic monopoles<br />
should appear as harmonic objects in this generalized non-abelian Hodge theory.<br />
All that is a part of the bigger project ``Holomorphic Floer theory",<br />
joint with Maxim Kontsevich.<br />
<br />
<br />
===Alicia Dickenstein (Buenos Aires)===<br />
<br />
Title: Algebra and geometry in the study of enzymatic cascades<br />
<br />
Abstract: In recent years, techniques from computational and real algebraic geometry have been successfully used to address mathematical challenges in systems biology. The algebraic theory of chemical reaction systems aims to understand their dynamic behavior by taking advantage of the inherent algebraic structure in the kinetic equations, and does not need the determination of the parameters a priori, which can be theoretically or practically impossible.<br />
I will give a gentle introduction to general results based on the network structure. In particular, I will describe a general framework for biological systems, called MESSI systems, that describe Modifications of type Enzyme-Substrate or Swap with Intermediates, and include many networks that model post-translational modifications of proteins inside the cell. I will also outline recent methods to address the important question of multistationarity, in particular in the study of enzymatic cascades, and will point out some of the mathematical challenges that arise from this application.<br />
<br />
<br />
=== Jianfeng Lu (Duke) ===<br />
Title: How to ``localize" the computation?<br />
<br />
It is often desirable to restrict the numerical computation to a local region to achieve best balance between accuracy and affordability in scientific computing. It is important to avoid artifacts and guarantee predictable modelling while artificial boundary conditions have to be introduced to restrict the computation. In this talk, we will discuss some recent understanding on how to achieve such local computation in the context of topological edge states and elliptic random media.<br />
<br />
===Eugenia Cheng (School of the Art Institute of Chicago)===<br />
<br />
Title: Character vs gender in mathematics and beyond<br />
<br />
Abstract: This presentation will be based on my experience of being a female mathematician, and teaching mathematics at all levels from elementary school to grad school. The question of why women are under-represented in mathematics is complex and there are no simple answers, only many many contributing factors. I will focus on character traits, and argue that if we focus on this rather than gender we can have a more productive and less divisive conversation. To try and focus on characters rather than genders I will introduce gender-neutral character adjectives "ingressive" and "congressive" to replace masculine and feminine. I will share my experience of teaching congressive abstract mathematics to art students, in a congressive way, and the possible effects this could have for everyone in mathematics, not just women.<br />
<br />
===Omer Mermelstein (Madison)===<br />
<br />
Title: Generic flat pregeometries<br />
<br />
Abstract: In model theory, the tamest of structures are the strongly minimal ones -- those in which every equation in a single variable has either finitely many or cofinitely many solution. Algebraically closed fields and vector spaces are the canonical examples. Zilber’s conjecture, later refuted by Hrushovski, states that the source of geometric complexity in a strongly minimal structure must be algebraic. The property of "flatness" (strict gammoid) of a geometry (matroid) is that which guarantees Hrushovski's construction is devoid of any associative structure.<br />
The majority of the talk will explain what flatness is, how it should be thought of, and how closely it relates to hypergraphs and Hrushovski's construction method. Model theory makes an appearance only in the second part, where I will share results pertaining to the specific family of geometries arising from Hrushovski's methods.<br />
<br />
<br />
===Shamgar Gurevich (Madison)===<br />
<br />
Title: Harmonic Analysis on GL(n) over Finite Fields.<br />
<br />
Abstract: There are many formulas that express interesting properties of a finite group G in terms of sums over its characters. For evaluating or estimating these sums, one of the most salient quantities to understand is the character ratio:<br />
<br />
trace(ρ(g)) / dim(ρ),<br />
<br />
for an irreducible representation ρ of G and an element g of G. For example, Diaconis and Shahshahani stated a formula of the mentioned type for analyzing certain random walks on G.<br />
<br />
Recently, we discovered that for classical groups G over finite fields there is a natural invariant of representations that provides strong information on the character ratio. We call this invariant rank. <br />
<br />
This talk will discuss the notion of rank for the group GLn over finite fields, demonstrate how it controls the character ratio, and explain how one can apply the results to verify mixing time and rate for certain random walks.<br />
<br />
This is joint work with Roger Howe (Yale and Texas AM). The numerics for this work was carried by Steve Goldstein (Madison)<br />
<br />
<br />
===Jose Rodriguez (UW-Madison)===<br />
Determining the closest point to a model (subset of Euclidean space) is an important problem in many applications in science,<br />
engineering, and statistics. One way to solve this problem is by minimizing the squared Euclidean distance function using a gradient<br />
descent approach. However, when there are multiple local minima, there is no guarantee of convergence to the true global minimizer.<br />
An alternative method is to determine the critical points of an objective function on the model.<br />
In algebraic statistics, the models of interest are algebraic sets, i.e., solution sets to a system of multivariate polynomial equations. In this situation, the number of critical points of the squared Euclidean distance function on the model’s Zariski closure is a topological invariant called the Euclidean distance degree (ED degree).<br />
In this talk, I will present some models from computer vision and statistics that may be described as algebraic sets. Moreover,<br />
I will describe a topological method for determining a Euclidean distance degree and a numerical algebraic geometry approach for<br />
determining critical points of the squared Euclidean distance function.<br />
<br />
=== Jeffrey Danciger (UT Austin) ===<br />
<br />
Title: TBA<br />
<br />
== Future Colloquia ==<br />
[[Colloquia/Blank|Blank]]<br />
<br />
== Past Colloquia ==<br />
<br />
[[Colloquia/Blank|Blank]]<br />
<br />
[[Colloquia/Spring2019|Spring 2019]]<br />
<br />
[[Colloquia/Fall2018|Fall 2018]]<br />
<br />
[[Colloquia/Spring2018|Spring 2018]]<br />
<br />
[[Colloquia/Fall2017|Fall 2017]]<br />
<br />
[[Colloquia/Spring2017|Spring 2017]]<br />
<br />
[[Archived Fall 2016 Colloquia|Fall 2016]]<br />
<br />
[[Colloquia/Spring2016|Spring 2016]]<br />
<br />
[[Colloquia/Fall2015|Fall 2015]]<br />
<br />
[[Colloquia/Spring2014|Spring 2015]]<br />
<br />
[[Colloquia/Fall2014|Fall 2014]]<br />
<br />
[[Colloquia/Spring2014|Spring 2014]]<br />
<br />
[[Colloquia/Fall2013|Fall 2013]]<br />
<br />
[[Colloquia 2012-2013|Spring 2013]]<br />
<br />
[[Colloquia 2012-2013#Fall 2012|Fall 2012]]</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/Spring2020&diff=18320Applied/ACMS/Spring20202019-11-04T16:54:41Z<p>Qinli: /* Spring 2020 */</p>
<hr />
<div>== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 31<br />
|[https://www.math.wisc.edu/~hung/ Hung Tran] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Hung Tran (UW-Madison)| Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel]]''<br />
| Li<br />
|-<br />
| Feb 7<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Feb 14<br />
|[http://math.mit.edu/~vadicgor/ Gorin Vadim] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Gorin Vadim (UW-Madison)|TBA, either random matrix or KPZ equation]]''<br />
| host<br />
|-<br />
| Feb 21<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Feb 28<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 6<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 13<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 20<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 27<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 3<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 10<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 17<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 24<br />
|[https://www.pml.unc.edu/ Pedro Saenz] (UNC)<br />
|''[[Applied/ACMS/absF19#Pedro Saenz (UNC)|TBA]]''<br />
| Spagnolie</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/Spring2020&diff=18319Applied/ACMS/Spring20202019-11-04T16:53:37Z<p>Qinli: /* Spring 2020 */</p>
<hr />
<div>== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 31<br />
|[https://www.math.wisc.edu/~hung/ Hung Tran] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Hung Tran (UW-Madison)| Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel]]''<br />
| Li<br />
|-<br />
| Feb 7<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Feb 14<br />
|[http://math.mit.edu/~vadicgor/ Gorin Vadim] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Gorin Vadim (UW-Madison)|title]]''<br />
| host<br />
|-<br />
| Feb 21<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Feb 28<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 6<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 13<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 20<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 27<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 3<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 10<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 17<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 24<br />
|[https://www.pml.unc.edu/ Pedro Saenz] (UNC)<br />
|''[[Applied/ACMS/absF19#Pedro Saenz (UNC)|TBA]]''<br />
| Spagnolie</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absS20&diff=18308Applied/ACMS/absS202019-11-04T15:10:15Z<p>Qinli: /* = */</p>
<hr />
<div>= ACMS Abstracts: Spring 2020 =<br />
<br />
=== Hung Tran ===<br />
<br />
Title: Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel<br />
<br />
Abstract: We study a critical case of Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel. Our method is based on the study of viscosity solutions to a new singular Hamilton-Jacobi equation, which results from applying the Bernstein transform to the original Coagulation-Fragmentation equation. Our results include wellposedness, regularity and long-time behaviors of viscosity solutions to the Hamilton-Jacobi equation in certain regimes, which have implications to wellposedness and long-time behaviors of mass-conserving solutions to the Coagulation-Fragmentation equation. Joint work with Truong-Son Van (CMU).</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absS20&diff=18307Applied/ACMS/absS202019-11-04T15:08:56Z<p>Qinli: </p>
<hr />
<div>===============<br />
Hung Tran, UW-Madison, Jan 31, 2020<br />
Title: Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel<br />
<br />
Abstract: We study a critical case of Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel. Our method is based on the study of viscosity solutions to a new singular Hamilton-Jacobi equation, which results from applying the Bernstein transform to the original Coagulation-Fragmentation equation. Our results include wellposedness, regularity and long-time behaviors of viscosity solutions to the Hamilton-Jacobi equation in certain regimes, which have implications to wellposedness and long-time behaviors of mass-conserving solutions to the Coagulation-Fragmentation equation. Joint work with Truong-Son Van (CMU).</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absS20&diff=18306Applied/ACMS/absS202019-11-04T15:08:24Z<p>Qinli: Created page with "Title: Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel Abstract: We study a critical case of Coagulation-Fragment..."</p>
<hr />
<div>Title: Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel<br />
<br />
Abstract: We study a critical case of Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel. Our method is based on the study of viscosity solutions to a new singular Hamilton-Jacobi equation, which results from applying the Bernstein transform to the original Coagulation-Fragmentation equation. Our results include wellposedness, regularity and long-time behaviors of viscosity solutions to the Hamilton-Jacobi equation in certain regimes, which have implications to wellposedness and long-time behaviors of mass-conserving solutions to the Coagulation-Fragmentation equation. Joint work with Truong-Son Van (CMU).</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/Spring2020&diff=18305Applied/ACMS/Spring20202019-11-04T15:08:11Z<p>Qinli: /* Spring 2020 */</p>
<hr />
<div>== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 31<br />
|[https://www.math.wisc.edu/~hung/ Hung Tran] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Hung Tran (UW-Madison)| Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel]]''<br />
| Li<br />
|-<br />
| Feb 7<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Feb 14<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Feb 21<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Feb 28<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 6<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 13<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 20<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 27<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 3<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 10<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 17<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 24<br />
|[https://www.pml.unc.edu/ Pedro Saenz] (UNC)<br />
|''[[Applied/ACMS/absF19#Pedro Saenz (UNC)|TBA]]''<br />
| Spagnolie</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/Spring2020&diff=18304Applied/ACMS/Spring20202019-11-04T15:07:56Z<p>Qinli: /* Spring 2020 */</p>
<hr />
<div>== Spring 2020 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Jan 31<br />
|[https://www.math.wisc.edu/~hung/] (UW-Madison)<br />
|''[[Applied/ACMS/absS20#Hung Tran (UW-Madison)| Coagulation-Fragmentation equations with multiplicative coagulation kernel and constant fragmentation kernel]]''<br />
| Li<br />
|-<br />
| Feb 7<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Feb 14<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Feb 21<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Feb 28<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 6<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 13<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 20<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Mar 27<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 3<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 10<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 17<br />
|[website] (institution)<br />
|''[[Applied/ACMS/absS20#Speaker (institution)|title]]''<br />
| host<br />
|-<br />
| Apr 24<br />
|[https://www.pml.unc.edu/ Pedro Saenz] (UNC)<br />
|''[[Applied/ACMS/absF19#Pedro Saenz (UNC)|TBA]]''<br />
| Spagnolie</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absF19&diff=18236Applied/ACMS/absF192019-10-23T18:00:05Z<p>Qinli: /* Tan Bui */</p>
<hr />
<div>= ACMS Abstracts: Fall 2019 =<br />
<br />
=== Leonardo Andrés Zepeda Núñez ===<br />
<br />
Title: Deep Learning for Electronic Structure Computations: A Tale of Symmetries, Locality, and Physics<br />
<br />
Abstract: Recently, the surge of interest in deep neural learning has dramatically improved image and signal processing, which has fueled breakthroughs in many domains such as drug discovery, genomics, and automatic translation. These advances have been further applied to scientific computing and, in particular, to electronic structure computations. In this case, the main objective is to directly compute the electron density, which encodes most of information of the system, thus bypassing the computationally intensive solution of the Kohn-Sham equations. However, similar to neural networks for image processing, the performance of the methods depends spectacularly on the physical and analytical intuition incorporated in the network, and on the training stage.<br />
<br />
In this talk, I will show how to build a network that respects physical symmetries and locality. I will show how to train the networks and how such properties impact the performance of the resulting network. Finally, I will present several examples for small yet realistic chemical systems.<br />
<br />
<br />
=== Daniel Floryan (UW-Madison) ===<br />
<br />
Title: Flexible Inertial Swimmers<br />
<br />
Abstract: Inertial swimmers deform their bodies and fins to push against the water and propel themselves forward. The deformation is driven partly by active musculature, and partly by passive elasticity. The interaction between elasticity and hydrodynamics confers features on the swimmers not enjoyed by their rigid friends, for example, boosts in speed when flapping at certain frequencies. We explain the salient features of flexible swimmers by drawing ideas from airfoils, vibrating beams, and flags flapping in the wind. The presence of fluid drag has important consequences. We also explore optimal arrangements of flexibility. (It turns out that nature is quite good.)<br />
<br />
<br />
=== Jianfeng Lu (Duke) ===<br />
<br />
Title: How to ``localize" the computation?<br />
<br />
It is often desirable to restrict the numerical computation to a local <br />
region to achieve best balance between accuracy and affordability in scientific computing. It is important to avoid artifacts and guarantee predictable modelling while artificial boundary conditions have to be introduced to restrict the computation. In this talk, we will discuss some recent understanding on how to achieve such local computation in the context of topological edge states and elliptic random media.<br />
<br />
<br />
=== Mitch Bushuk (GFDL/Princeton) ===<br />
<br />
Title: Arctic Sea Ice Predictability in a Changing Cryosphere<br />
<br />
Abstract: Forty years of satellite observations have documented a striking decline in the areal extent of Arctic sea ice. The loss of sea ice has impacts on the climate system, human populations, ecosystems, and natural environments across a broad range of spatial and temporal scales. These changes have motivated significant research interest in the predictability and prediction of Arctic sea ice on seasonal-to-interannual timescales. In this talk, I will address two related questions: (1) What is the inherent predictability of Arctic sea ice and what physical mechanisms underlie this predictability? and (2) How can this knowledge be leveraged to improve operational sea ice predictions? I will present findings on the relative roles of the ocean, sea ice, and atmosphere in controlling Arctic sea ice predictability. I will also present evidence for an Arctic spring predictability barrier, which may impose a sharp limit on our ability to make skillful predictions of the summer sea ice minimum. <br />
<br />
<br />
=== Qin Li (UW-Madison) ===<br />
<br />
Title: The power of randomness in scientific computing<br />
<br />
Abstract: Most numerical methods in scientific computing are deterministic. Traditionally, accuracy has been the target while the cost was not the concern. However, in this era of big data, we incline to relax the strict requirements on the accuracy to reduce numerical cost. Introducing randomness in the numerical solvers could potentially speed up the computation significantly at small sacrifice of accuracy. In this talk, I'd like to show two concrete examples how this is done: first on random sketching in experimental design, and the second on numerical homgenization, hoping the discussion can shed light on potential other applications. Joint work with Ke Chen, Jianfeng Lu, Kit Newton and Stephen Wright.<br />
<br />
<br />
=== Joel Nishimura (Arizona State) ===<br />
<br />
Title: Random graph models with fixed degree sequences: choices, consequences and irreducibility proofs for sampling<br />
<br />
Abstract: Determining which features of an empirical graph are noteworthy frequently relies upon the ability to sample random graphs with constrained properties. Since empirical graphs have distinctive degree sequences, one of the most popular random graph models is the configuration model, which produces a graph uniformly at random from the set of graphs with a fixed degree sequence. While it is commonly treated as though there is only a single configuration model, one sampled via stub-matching, there are many, depending on whether self-loops and multiedges are allowed and whether edge stubs are labeled or not. We show, these different configuration models can lead to drastically, sometimes opposite, interpretations of empirical graphs. In order to sample from these different configuration models, we review and develop the underpinnings of Markov chain Monte Carlo methods based upon double-edge swaps. We also present new results on the irreducibility of the Markov chain for graphs with self-loops, either proving irreducibility or exactly characterizing the degree sequences for which the Markov chain is reducible. This work completes the study of the irreducibility of double edge-swap Markov chains (and the related Curveball Markov chain) for all combinations of allowing self-loops, multiple self-loops and/or multiedges. <br />
<br />
<br />
=== Alex Townsend (Cornell) ===<br />
<br />
Title: Why are so many matrices and tensors of low rank in computational mathematics?<br />
<br />
Abstract: Matrices and tensors that appear in computational mathematics are so often well-approximated by low-rank objects. Since random ("average") matrices are almost surely of full rank, mathematics needs to explain the abundance of low-rank structures. We will give various methodologies that allow one to begin to understand the prevalence of compressible matrices and tensors and we hope to reveal an underlying link between disparate applications. In particular, we will show how one can connect the singular values of a matrix with displacement structure to a rational approximation problem that highlights fundamental connections between polynomial interpolation, Krylov methods, and fast Toeplitz solvers.<br />
<br />
<br />
=== Prashant G. Mehta ===<br />
<br />
Title: What is the Lagrangian for Nonlinear Filtering?<br />
<br />
Abstract: There is a certain magic involved in recasting the equations in Physics, and the algorithms in Engineering, in variational terms. The most classical of these ‘magics’ is the Lagrange’s formulation of the Newtonian mechanics. An accessible modern take on all this and more appears in the February 19, 2019 issue of The New Yorker magazine: https://www.newyorker.com/science/elements/a-different-kind-of-theory-of-everything?reload=true <br />
<br />
My talk is concerned with a variational (optimal control type) formulation of the problem of nonlinear filtering/estimation. Such formulations are referred to as duality between optimal estimation and optimal control. The first duality principle appears in the seminal (1961) paper of Kalman-Bucy, where the problem of minimum variance estimation is shown to be dual to a linear quadratic optimal control problem. <br />
<br />
In my talk, I will describe a generalization of the Kalman-Bucy duality theory to nonlinear filtering. The generalization is an exact extension, in the sense that the dual optimal control problem has the same minimum variance structure for linear and nonlinear filtering problems. Kalman-Bucy’s classical result is shown to be a special case. During the talk, I will also attempt to review other types of duality relationships that have appeared over the years for the problem of linear and nonlinear filtering. <br />
<br />
This is joint work with Jin Won Kim and Sean Meyn. The talk is based on the following papers: https://arxiv.org/pdf/1903.11195.pdf and https://arxiv.org/pdf/1904.01710.pdf.<br />
<br />
<br />
=== Jean-Luc Thiffeault ===<br />
<br />
We consider a simple model of a two-dimensional microswimmer with fixed swimming speed. The direction of swimming changes according to<br />
a Brownian process, and the swimmer is interacting with boundaries. This is a standard model for a simple microswimmer, or a confined<br />
wormlike chain polymer. The shape of the swimmer determines the range of allowable values that its degrees of freedom can assume --- its<br />
configuration space. Using natural assumptions about reflection of the swimmer at boundaries, we compute the swimmer's invariant<br />
distribution across a channel consisting of two parallel walls, and the statistics of spreading in the longitudinal direction. This gives<br />
us the effective diffusion constant of the swimmer's large scale motion. When the swimmer is longer than the channel width, it cannot<br />
reverse, and we then compute the mean drift velocity of the swimmer. This model offers insight into experiments of scattering of swimmers<br />
from boundaries, and serves as an exactly-solvable baseline when comparing to more complex models. This is joint work with Hongfei Chen.<br />
<br />
<br />
=== Tan Bui (UT-Austin) ===<br />
<br />
Title: Scalable Algorithms for Data-driven Inverse and Learning Problems<br />
<br />
Abstract: Inverse problems and uncertainty quantification (UQ) are pervasive in scientific discovery and decision-making for complex, natural, engineered, and societal systems. They are perhaps the most popular mathematical approaches for enabling predictive scientific simulations that integrate observational/experimental data, simulations and/or models. Unfortunately, inverse/UQ problems for practical complex systems possess these the simultaneous challenges: the large-scale forward problem challenge, the high dimensional parameter space challenge, and the big data challenge.<br />
<br />
To address the first challenge, we have developed parallel high-order (hybridized) discontinuous Galerkin methods to discretize complex forward PDEs. <br />
To address the second challenge, we have developed various approaches from model reduction to advanced Markov chain Monte Carlo methods to effectively explore high dimensional parameter spaces to compute posterior statistics. To address the last challenge, we have developed a randomized misfit approach that uncovers the interplay between the Johnson-Lindenstrauss and the Morozov's discrepancy principle to significantly reduce the dimension of the data without compromising the quality of the inverse solutions.<br />
<br />
In this talk we selectively present scalable and rigorous approaches to tackle these challenges for PDE-governed Bayesian inverse problems. Various numerical results for simple to complex PDEs will be presented to verify our algorithms and theoretical findings. If time permits, we will present our recent work on scientific machine learning for inverse and learning problems.</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absF19&diff=18235Applied/ACMS/absF192019-10-23T17:59:50Z<p>Qinli: /* ACMS Abstracts: Fall 2019 */</p>
<hr />
<div>= ACMS Abstracts: Fall 2019 =<br />
<br />
=== Leonardo Andrés Zepeda Núñez ===<br />
<br />
Title: Deep Learning for Electronic Structure Computations: A Tale of Symmetries, Locality, and Physics<br />
<br />
Abstract: Recently, the surge of interest in deep neural learning has dramatically improved image and signal processing, which has fueled breakthroughs in many domains such as drug discovery, genomics, and automatic translation. These advances have been further applied to scientific computing and, in particular, to electronic structure computations. In this case, the main objective is to directly compute the electron density, which encodes most of information of the system, thus bypassing the computationally intensive solution of the Kohn-Sham equations. However, similar to neural networks for image processing, the performance of the methods depends spectacularly on the physical and analytical intuition incorporated in the network, and on the training stage.<br />
<br />
In this talk, I will show how to build a network that respects physical symmetries and locality. I will show how to train the networks and how such properties impact the performance of the resulting network. Finally, I will present several examples for small yet realistic chemical systems.<br />
<br />
<br />
=== Daniel Floryan (UW-Madison) ===<br />
<br />
Title: Flexible Inertial Swimmers<br />
<br />
Abstract: Inertial swimmers deform their bodies and fins to push against the water and propel themselves forward. The deformation is driven partly by active musculature, and partly by passive elasticity. The interaction between elasticity and hydrodynamics confers features on the swimmers not enjoyed by their rigid friends, for example, boosts in speed when flapping at certain frequencies. We explain the salient features of flexible swimmers by drawing ideas from airfoils, vibrating beams, and flags flapping in the wind. The presence of fluid drag has important consequences. We also explore optimal arrangements of flexibility. (It turns out that nature is quite good.)<br />
<br />
<br />
=== Jianfeng Lu (Duke) ===<br />
<br />
Title: How to ``localize" the computation?<br />
<br />
It is often desirable to restrict the numerical computation to a local <br />
region to achieve best balance between accuracy and affordability in scientific computing. It is important to avoid artifacts and guarantee predictable modelling while artificial boundary conditions have to be introduced to restrict the computation. In this talk, we will discuss some recent understanding on how to achieve such local computation in the context of topological edge states and elliptic random media.<br />
<br />
<br />
=== Mitch Bushuk (GFDL/Princeton) ===<br />
<br />
Title: Arctic Sea Ice Predictability in a Changing Cryosphere<br />
<br />
Abstract: Forty years of satellite observations have documented a striking decline in the areal extent of Arctic sea ice. The loss of sea ice has impacts on the climate system, human populations, ecosystems, and natural environments across a broad range of spatial and temporal scales. These changes have motivated significant research interest in the predictability and prediction of Arctic sea ice on seasonal-to-interannual timescales. In this talk, I will address two related questions: (1) What is the inherent predictability of Arctic sea ice and what physical mechanisms underlie this predictability? and (2) How can this knowledge be leveraged to improve operational sea ice predictions? I will present findings on the relative roles of the ocean, sea ice, and atmosphere in controlling Arctic sea ice predictability. I will also present evidence for an Arctic spring predictability barrier, which may impose a sharp limit on our ability to make skillful predictions of the summer sea ice minimum. <br />
<br />
<br />
=== Qin Li (UW-Madison) ===<br />
<br />
Title: The power of randomness in scientific computing<br />
<br />
Abstract: Most numerical methods in scientific computing are deterministic. Traditionally, accuracy has been the target while the cost was not the concern. However, in this era of big data, we incline to relax the strict requirements on the accuracy to reduce numerical cost. Introducing randomness in the numerical solvers could potentially speed up the computation significantly at small sacrifice of accuracy. In this talk, I'd like to show two concrete examples how this is done: first on random sketching in experimental design, and the second on numerical homgenization, hoping the discussion can shed light on potential other applications. Joint work with Ke Chen, Jianfeng Lu, Kit Newton and Stephen Wright.<br />
<br />
<br />
=== Joel Nishimura (Arizona State) ===<br />
<br />
Title: Random graph models with fixed degree sequences: choices, consequences and irreducibility proofs for sampling<br />
<br />
Abstract: Determining which features of an empirical graph are noteworthy frequently relies upon the ability to sample random graphs with constrained properties. Since empirical graphs have distinctive degree sequences, one of the most popular random graph models is the configuration model, which produces a graph uniformly at random from the set of graphs with a fixed degree sequence. While it is commonly treated as though there is only a single configuration model, one sampled via stub-matching, there are many, depending on whether self-loops and multiedges are allowed and whether edge stubs are labeled or not. We show, these different configuration models can lead to drastically, sometimes opposite, interpretations of empirical graphs. In order to sample from these different configuration models, we review and develop the underpinnings of Markov chain Monte Carlo methods based upon double-edge swaps. We also present new results on the irreducibility of the Markov chain for graphs with self-loops, either proving irreducibility or exactly characterizing the degree sequences for which the Markov chain is reducible. This work completes the study of the irreducibility of double edge-swap Markov chains (and the related Curveball Markov chain) for all combinations of allowing self-loops, multiple self-loops and/or multiedges. <br />
<br />
<br />
=== Alex Townsend (Cornell) ===<br />
<br />
Title: Why are so many matrices and tensors of low rank in computational mathematics?<br />
<br />
Abstract: Matrices and tensors that appear in computational mathematics are so often well-approximated by low-rank objects. Since random ("average") matrices are almost surely of full rank, mathematics needs to explain the abundance of low-rank structures. We will give various methodologies that allow one to begin to understand the prevalence of compressible matrices and tensors and we hope to reveal an underlying link between disparate applications. In particular, we will show how one can connect the singular values of a matrix with displacement structure to a rational approximation problem that highlights fundamental connections between polynomial interpolation, Krylov methods, and fast Toeplitz solvers.<br />
<br />
<br />
=== Prashant G. Mehta ===<br />
<br />
Title: What is the Lagrangian for Nonlinear Filtering?<br />
<br />
Abstract: There is a certain magic involved in recasting the equations in Physics, and the algorithms in Engineering, in variational terms. The most classical of these ‘magics’ is the Lagrange’s formulation of the Newtonian mechanics. An accessible modern take on all this and more appears in the February 19, 2019 issue of The New Yorker magazine: https://www.newyorker.com/science/elements/a-different-kind-of-theory-of-everything?reload=true <br />
<br />
My talk is concerned with a variational (optimal control type) formulation of the problem of nonlinear filtering/estimation. Such formulations are referred to as duality between optimal estimation and optimal control. The first duality principle appears in the seminal (1961) paper of Kalman-Bucy, where the problem of minimum variance estimation is shown to be dual to a linear quadratic optimal control problem. <br />
<br />
In my talk, I will describe a generalization of the Kalman-Bucy duality theory to nonlinear filtering. The generalization is an exact extension, in the sense that the dual optimal control problem has the same minimum variance structure for linear and nonlinear filtering problems. Kalman-Bucy’s classical result is shown to be a special case. During the talk, I will also attempt to review other types of duality relationships that have appeared over the years for the problem of linear and nonlinear filtering. <br />
<br />
This is joint work with Jin Won Kim and Sean Meyn. The talk is based on the following papers: https://arxiv.org/pdf/1903.11195.pdf and https://arxiv.org/pdf/1904.01710.pdf.<br />
<br />
<br />
=== Jean-Luc Thiffeault ===<br />
<br />
We consider a simple model of a two-dimensional microswimmer with fixed swimming speed. The direction of swimming changes according to<br />
a Brownian process, and the swimmer is interacting with boundaries. This is a standard model for a simple microswimmer, or a confined<br />
wormlike chain polymer. The shape of the swimmer determines the range of allowable values that its degrees of freedom can assume --- its<br />
configuration space. Using natural assumptions about reflection of the swimmer at boundaries, we compute the swimmer's invariant<br />
distribution across a channel consisting of two parallel walls, and the statistics of spreading in the longitudinal direction. This gives<br />
us the effective diffusion constant of the swimmer's large scale motion. When the swimmer is longer than the channel width, it cannot<br />
reverse, and we then compute the mean drift velocity of the swimmer. This model offers insight into experiments of scattering of swimmers<br />
from boundaries, and serves as an exactly-solvable baseline when comparing to more complex models. This is joint work with Hongfei Chen.<br />
<br />
<br />
=== Tan Bui ===<br />
<br />
Title: Scalable Algorithms for Data-driven Inverse and Learning Problems<br />
<br />
Abstract: Inverse problems and uncertainty quantification (UQ) are pervasive in scientific discovery and decision-making for complex, natural, engineered, and societal systems. They are perhaps the most popular mathematical approaches for enabling predictive scientific simulations that integrate observational/experimental data, simulations and/or models. Unfortunately, inverse/UQ problems for practical complex systems possess these the simultaneous challenges: the large-scale forward problem challenge, the high dimensional parameter space challenge, and the big data challenge.<br />
<br />
To address the first challenge, we have developed parallel high-order (hybridized) discontinuous Galerkin methods to discretize complex forward PDEs. <br />
To address the second challenge, we have developed various approaches from model reduction to advanced Markov chain Monte Carlo methods to effectively explore high dimensional parameter spaces to compute posterior statistics. To address the last challenge, we have developed a randomized misfit approach that uncovers the interplay between the Johnson-Lindenstrauss and the Morozov's discrepancy principle to significantly reduce the dimension of the data without compromising the quality of the inverse solutions.<br />
<br />
In this talk we selectively present scalable and rigorous approaches to tackle these challenges for PDE-governed Bayesian inverse problems. Various numerical results for simple to complex PDEs will be presented to verify our algorithms and theoretical findings. If time permits, we will present our recent work on scientific machine learning for inverse and learning problems.</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=18234Applied/ACMS2019-10-23T17:58:21Z<p>Qinli: /* Fall 2019 */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li], [http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
<br />
== Fall 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Sept 6<br />
|[http://math.mit.edu/~lzepeda/ Leonardo Andrés Zepeda Núñez] (UW-Madison)<br />
|''[[Applied/ACMS/absF19#Leonardo Andrés Zepeda Núñez (UW-Madison)|Deep Learning for Electronic Structure Computations: A Tale of Symmetries, Locality, and Physics]]''<br />
| Li<br />
|-<br />
| Sept 13<br />
|[http://dfloryan.mycpanel.princeton.edu/ Daniel Floryan] (UW-Madison)<br />
|''[[Applied/ACMS/absF19#Daniel Floryan (UW-Madison)|Flexible Inertial Swimmers]]''<br />
| Jean-Luc<br />
|-<br />
| Sept 14-15<br />
|[https://www.ams.org/meetings/sectional/2267_program.html AMS sectional meeting]<br />
| UW-Madison<br />
|-<br />
| Sept 20<br />
|[https://www.gfdl.noaa.gov/mitch-bushuk/ Mitch Bushuk] (GFDL/Princeton)<br />
|''[[Applied/ACMS/absF19#Mitch Bushuk (GFDL/Princeton)|Arctic Sea Ice Predictability in a Changing Cryosphere]]''<br />
| Chen<br />
|-<br />
| Sept 20 (colloquium, 4pm, B239)<br />
|[https://services.math.duke.edu/~jianfeng/ Jianfeng Lu] (Duke)<br />
|''[[Applied/ACMS/absF19#Jianfeng Lu (Duke)|How to "localize" the computation?]]''<br />
| Li<br />
|-<br />
| Sept 27<br />
|[http://www.math.wisc.edu/~qinli/ Qin Li] (UW-Madison)<br />
|''[[Applied/ACMS/absF19#Qin Li (UW-Madison)|The power of randomness in scientific computing]]''<br />
| host<br />
|-<br />
| Oct 4<br />
|[https://isearch.asu.edu/profile/2169104 Joel Nishimura] (Arizona State)<br />
|''[[Applied/ACMS/absF19#Joel Nishimura (Arizona State)|Random graph models with fixed degree sequences: choices, consequences and irreducibility proofs for sampling]]''<br />
| Cochran<br />
|-<br />
| Oct 11<br />
|[http://pi.math.cornell.edu/~ajt/ Alex Townsend] (Cornell)<br />
|''[[Applied/ACMS/absF19#Alex Townsend (Cornell)|Why are so many matrices and tensors of low rank in computational mathematics?]]''<br />
| Li<br />
|-<br />
| Oct 18<br />
|[http://mehta.mechse.illinois.edu/ Prashant G. Mehta] (UIUC)<br />
|''[[Applied/ACMS/absF19#Prashant G. Mehta (UIUC)|What is the Lagrangian for Nonlinear Filtering?]]''<br />
| Chen<br />
|-<br />
| Oct 25<br />
|[https://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault] (UW-Madison)<br />
|''[[Applied/ACMS/absF19#Jean-Luc Thiffeault|Shape matters: A Brownian microswimmer interacting with walls]]''<br />
| <br />
|-<br />
| Nov 1<br />
|[https://users.oden.utexas.edu/~tanbui/ Tan Bui] (UT-Austin)<br />
|''[[Applied/ACMS/absF19#Tan Bui (UT-Austin)|Scalable Algorithms for Data-driven Inverse and Learning Problems]]''<br />
| Li<br />
|-<br />
| Nov 8<br />
|[https://pan.labs.wisc.edu/staff/pan-wenxiao/ Wenxiao Pan] (UW)<br />
|''[[Applied/ACMS/absF19#Wenxiao Pan (UW)|TBA]]''<br />
| Spagnolie<br />
| <br />
|-<br />
| Nov 15<br />
|[https://www.math.wisc.edu/~pgera/ Prerna Gera] (UW)<br />
|''[[Applied/ACMS/absF19#Prerna Gera (UW)|TBA]]''<br />
| Spagnolie<br />
|-<br />
| Dec 6<br />
|[https://math.berkeley.edu/~linlin/ Lin Lin] (Berkeley)<br />
|''[[Applied/ACMS/absF19#Lin Lin (UC Berkeley)|TBA]]''<br />
| Li<br />
|-<br />
|}<br />
<br />
== Future semesters ==<br />
<br />
*[[Applied/ACMS/Spring2020|Spring 2020]]<br />
<br />
== Archived semesters ==<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=PDE_Geometric_Analysis_seminar&diff=18147PDE Geometric Analysis seminar2019-10-11T18:58:02Z<p>Qinli: /* Claude Bardos */</p>
<hr />
<div>The seminar will be held in room 901 of Van Vleck Hall on Mondays from 3:30pm - 4:30pm, unless indicated otherwise.<br />
<br />
===[[Previous PDE/GA seminars]]===<br />
===[[Fall 2020-Spring 2021 | Tentative schedule for Fall 2020-Spring 2021]]===<br />
<br />
== PDE GA Seminar Schedule Fall 2019-Spring 2020 ==<br />
<br />
<br />
{| cellpadding="8"<br />
!style="width:20%" align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!style="width:20%" align="left" | host(s)<br />
|- <br />
|Sep 9<br />
| Scott Smith (UW Madison)<br />
|[[#Scott Smith | Recent progress on singular, quasi-linear stochastic PDE ]]<br />
| Kim and Tran<br />
|- <br />
|Sep 14-15<br />
| <br />
|[[ # |AMS Fall Central Sectional Meeting https://www.ams.org/meetings/sectional/2267_program.html ]]<br />
| <br />
|- <br />
|Sep 23<br />
| Son Tu (UW Madison)<br />
|[[#Son Tu | State-Constraint static Hamilton-Jacobi equations in nested domains ]]<br />
| Kim and Tran<br />
|- <br />
|Sep 28-29, VV901<br />
| https://www.ki-net.umd.edu/content/conf?event_id=993<br />
| | Recent progress in analytical aspects of kinetic equations and related fluid models <br />
| <br />
|- <br />
|Oct 7<br />
| Jin Woo Jang (Postech)<br />
|[[#Jin Woo Jang| On a Cauchy problem for the Landau-Boltzmann equation ]]<br />
| Kim<br />
|- <br />
|Oct 14<br />
| Stefania Patrizi (UT Austin)<br />
|[[#Stefania Patrizi | TBA ]]<br />
| Tran<br />
|- <br />
|Oct 21<br />
| Claude Bardos (Université Paris Denis Diderot, France)<br />
|[[#Claude Bardos | From d'Alembert paradox to 1984 Kato criteria via 1941 1/3 Kolmogorov law and 1949 Onsager conjecture ]]<br />
| Li<br />
|- <br />
|Oct 28<br />
| Albert Ai (UW Madison)<br />
|[[#Albert Ai | TBA ]]<br />
| Ifrim<br />
|- <br />
|Nov 4<br />
| Yunbai Cao (UW Madison)<br />
|[[#Yunbai Cao | TBA ]]<br />
| Kim and Tran<br />
|- <br />
|Nov 11<br />
| Speaker (Institute)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|- <br />
|Nov 18<br />
| Speaker (Institute)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|-<br />
|Nov 25<br />
| Mathew Langford (UT Knoxville)<br />
|[[#Speaker | TBA ]]<br />
| Angenent<br />
|- <br />
|- <br />
|Feb 17<br />
| Yannick Sire (JHU)<br />
|[[#Yannick Sire (JHU) | TBA ]]<br />
| Tran<br />
|- <br />
|Feb 24<br />
| Speaker (Institute)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|- <br />
|March 2<br />
| Theodora Bourni (UT Knoxville)<br />
|[[#Speaker | TBA ]]<br />
| Angenent<br />
|- <br />
|March 9<br />
| Ian Tice (CMU)<br />
|[[#Ian Tice| TBA ]]<br />
| Kim<br />
|- <br />
|March 16 <br />
| No seminar (spring break)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|- <br />
|March 23<br />
| Jared Speck (Vanderbilt)<br />
|[[#Jared Speck | TBA ]]<br />
| SCHRECKER<br />
|- <br />
|March 30<br />
| Speaker (Institute)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|- <br />
|April 6<br />
| Speaker (Institute)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|- <br />
|April 13<br />
| Speaker (Institute)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|- <br />
|April 20<br />
| Hyunju Kwon (IAS)<br />
|[[#Hyunju Kwon | TBA ]]<br />
| Kim<br />
|- <br />
|April 27<br />
| Speaker (Institute)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|}<br />
<br />
== Abstracts ==<br />
<br />
===Scott Smith===<br />
<br />
Title: Recent progress on singular, quasi-linear stochastic PDE<br />
<br />
Abstract: This talk with focus on quasi-linear parabolic equations with an irregular forcing . These equations are ill-posed in the traditional sense of distribution theory. They require flexibility in the notion of solution as well as new a priori bounds. Drawing on the philosophy of rough paths and regularity structures, we develop the analytic part of a small data solution theory. This is joint work with Felix Otto, Hendrik Weber, and Jonas Sauer.<br />
<br />
<br />
===Son Tu===<br />
<br />
Title: State-Constraint static Hamilton-Jacobi equations in nested domains<br />
<br />
Abstract: We study state-constraint static Hamilton-Jacobi equations in a sequence of domains $\{\Omega_k\}$ in $\mathbb R^n$ such that $\Omega_k \subset \Omega_{k+1}$ for all $k \in \mathbb N$. We obtain rates of convergence of $u_k$, the solution to the state-constraint problem in $\Omega_k$, to $u$, the solution to the corresponding problem in $\Omega=\bigcup_k \Omega_k$. In many cases, the rates obtained are proven to be optimal (it's a joint work with Yeoneung Kim and Hung V. Tran).<br />
<br />
<br />
===Jin Woo Jang===<br />
<br />
Title: On a Cauchy problem for the Landau-Boltzmann equation<br />
<br />
Abstract: In this talk, I will introduce a recent development in the global well-posedness of the Landau equation (1936) in a general smooth bounded domain, which has been a long-outstanding open problem. This work proves the global stability of the Landau equation in an $L^\infty_{x,v}$ framework with the Coulombic potential in a general smooth bounded domain with the specular reflection boundary condition for initial perturbations of the Maxwellian equilibrium states. Our methods consist of the generalization of the well-posedness theory for the kinetic Fokker-Planck equation (HJV-2014, HJJ-2018) and the extension of the boundary value problem to a whole space problem, as well as the use of a recent extension of De Giorgi-Nash-Moser theory for the kinetic Fokker-Planck equations (GIMV-2016) and the Morrey estimates (BCM-1996) to further control the velocity derivatives, which ensures the uniqueness. This is a joint work with Y. Guo, H. J. Hwang, and Z. Ouyang.<br />
<br />
<br />
=== Claude Bardos ===<br />
Title: From the d'Alembert paradox to the 1984 Kato criteria via the 1941 $1/3$ Kolmogorov law and the 1949 Onsager conjecture<br />
<br />
Abstract: Several of my recent contributions, with Marie Farge, Edriss Titi, Emile Wiedemann, Piotr and Agneska Gwiadza, were motivated by the following issues: The role of boundary effect in mathematical theory of fluids mechanic and the similarity, in presence of these effects, of the weak convergence in the zero viscosity limit and the statistical theory of turbulence. As a consequence, I will recall the Onsager conjecture and compare it to the issue of anomalous energy dissipation.<br />
<br />
Then I will give a proof of the local conservation of energy under convenient hypothesis in a domain with boundary and give supplementary condition that imply the global conservation of energy in a domain with boundary and the absence of anomalous energy dissipation in the zero viscosity limit of solutions of the Navier-Stokes equation in the presence of no slip boundary condition.<br />
<br />
Eventually the above results are compared with several forms of a basic theorem of Kato in the presence of a Lipschitz solution of the Euler equations and one may insist on the fact that in such case the the absence of anomalous energy dissipation is {\bf equivalent} to the persistence of regularity in the zero viscosity limit. Eventually this remark contributes to the resolution of the d'Alembert Paradox.</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=PDE_Geometric_Analysis_seminar&diff=18146PDE Geometric Analysis seminar2019-10-11T18:57:48Z<p>Qinli: /* Claude Bardos */</p>
<hr />
<div>The seminar will be held in room 901 of Van Vleck Hall on Mondays from 3:30pm - 4:30pm, unless indicated otherwise.<br />
<br />
===[[Previous PDE/GA seminars]]===<br />
===[[Fall 2020-Spring 2021 | Tentative schedule for Fall 2020-Spring 2021]]===<br />
<br />
== PDE GA Seminar Schedule Fall 2019-Spring 2020 ==<br />
<br />
<br />
{| cellpadding="8"<br />
!style="width:20%" align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!style="width:20%" align="left" | host(s)<br />
|- <br />
|Sep 9<br />
| Scott Smith (UW Madison)<br />
|[[#Scott Smith | Recent progress on singular, quasi-linear stochastic PDE ]]<br />
| Kim and Tran<br />
|- <br />
|Sep 14-15<br />
| <br />
|[[ # |AMS Fall Central Sectional Meeting https://www.ams.org/meetings/sectional/2267_program.html ]]<br />
| <br />
|- <br />
|Sep 23<br />
| Son Tu (UW Madison)<br />
|[[#Son Tu | State-Constraint static Hamilton-Jacobi equations in nested domains ]]<br />
| Kim and Tran<br />
|- <br />
|Sep 28-29, VV901<br />
| https://www.ki-net.umd.edu/content/conf?event_id=993<br />
| | Recent progress in analytical aspects of kinetic equations and related fluid models <br />
| <br />
|- <br />
|Oct 7<br />
| Jin Woo Jang (Postech)<br />
|[[#Jin Woo Jang| On a Cauchy problem for the Landau-Boltzmann equation ]]<br />
| Kim<br />
|- <br />
|Oct 14<br />
| Stefania Patrizi (UT Austin)<br />
|[[#Stefania Patrizi | TBA ]]<br />
| Tran<br />
|- <br />
|Oct 21<br />
| Claude Bardos (Université Paris Denis Diderot, France)<br />
|[[#Claude Bardos | From d'Alembert paradox to 1984 Kato criteria via 1941 1/3 Kolmogorov law and 1949 Onsager conjecture ]]<br />
| Li<br />
|- <br />
|Oct 28<br />
| Albert Ai (UW Madison)<br />
|[[#Albert Ai | TBA ]]<br />
| Ifrim<br />
|- <br />
|Nov 4<br />
| Yunbai Cao (UW Madison)<br />
|[[#Yunbai Cao | TBA ]]<br />
| Kim and Tran<br />
|- <br />
|Nov 11<br />
| Speaker (Institute)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|- <br />
|Nov 18<br />
| Speaker (Institute)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|-<br />
|Nov 25<br />
| Mathew Langford (UT Knoxville)<br />
|[[#Speaker | TBA ]]<br />
| Angenent<br />
|- <br />
|- <br />
|Feb 17<br />
| Yannick Sire (JHU)<br />
|[[#Yannick Sire (JHU) | TBA ]]<br />
| Tran<br />
|- <br />
|Feb 24<br />
| Speaker (Institute)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|- <br />
|March 2<br />
| Theodora Bourni (UT Knoxville)<br />
|[[#Speaker | TBA ]]<br />
| Angenent<br />
|- <br />
|March 9<br />
| Ian Tice (CMU)<br />
|[[#Ian Tice| TBA ]]<br />
| Kim<br />
|- <br />
|March 16 <br />
| No seminar (spring break)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|- <br />
|March 23<br />
| Jared Speck (Vanderbilt)<br />
|[[#Jared Speck | TBA ]]<br />
| SCHRECKER<br />
|- <br />
|March 30<br />
| Speaker (Institute)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|- <br />
|April 6<br />
| Speaker (Institute)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|- <br />
|April 13<br />
| Speaker (Institute)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|- <br />
|April 20<br />
| Hyunju Kwon (IAS)<br />
|[[#Hyunju Kwon | TBA ]]<br />
| Kim<br />
|- <br />
|April 27<br />
| Speaker (Institute)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|}<br />
<br />
== Abstracts ==<br />
<br />
===Scott Smith===<br />
<br />
Title: Recent progress on singular, quasi-linear stochastic PDE<br />
<br />
Abstract: This talk with focus on quasi-linear parabolic equations with an irregular forcing . These equations are ill-posed in the traditional sense of distribution theory. They require flexibility in the notion of solution as well as new a priori bounds. Drawing on the philosophy of rough paths and regularity structures, we develop the analytic part of a small data solution theory. This is joint work with Felix Otto, Hendrik Weber, and Jonas Sauer.<br />
<br />
<br />
===Son Tu===<br />
<br />
Title: State-Constraint static Hamilton-Jacobi equations in nested domains<br />
<br />
Abstract: We study state-constraint static Hamilton-Jacobi equations in a sequence of domains $\{\Omega_k\}$ in $\mathbb R^n$ such that $\Omega_k \subset \Omega_{k+1}$ for all $k \in \mathbb N$. We obtain rates of convergence of $u_k$, the solution to the state-constraint problem in $\Omega_k$, to $u$, the solution to the corresponding problem in $\Omega=\bigcup_k \Omega_k$. In many cases, the rates obtained are proven to be optimal (it's a joint work with Yeoneung Kim and Hung V. Tran).<br />
<br />
<br />
===Jin Woo Jang===<br />
<br />
Title: On a Cauchy problem for the Landau-Boltzmann equation<br />
<br />
Abstract: In this talk, I will introduce a recent development in the global well-posedness of the Landau equation (1936) in a general smooth bounded domain, which has been a long-outstanding open problem. This work proves the global stability of the Landau equation in an $L^\infty_{x,v}$ framework with the Coulombic potential in a general smooth bounded domain with the specular reflection boundary condition for initial perturbations of the Maxwellian equilibrium states. Our methods consist of the generalization of the well-posedness theory for the kinetic Fokker-Planck equation (HJV-2014, HJJ-2018) and the extension of the boundary value problem to a whole space problem, as well as the use of a recent extension of De Giorgi-Nash-Moser theory for the kinetic Fokker-Planck equations (GIMV-2016) and the Morrey estimates (BCM-1996) to further control the velocity derivatives, which ensures the uniqueness. This is a joint work with Y. Guo, H. J. Hwang, and Z. Ouyang.<br />
<br />
<br />
=== Claude Bardos ===<br />
Title: From the d'Alembert paradox to the 1984 Kato criteria via the 1941 $1/3$ Kolmogorov law and the 1949 Onsager conjecture<br />
<br />
Abstract: Several of my recent contributions, with Marie Farge, Edriss Titi, Emile Wiedemann, Piotr and Agneska Gwiadza, were motivated by the following issues:<br />
<br />
The role of boundary effect in mathematical theory of fluids mechanic and the similarity, in presence of these effects, of the weak convergence in the zero viscosity limit and the statistical theory of turbulence. <br />
<br />
As a consequence, I will recall the Onsager conjecture and compare it to the issue of anomalous energy dissipation.<br />
<br />
Then I will give a proof of the local conservation of energy under convenient hypothesis in a domain with boundary and give supplementary condition that imply the global conservation of energy in a domain with boundary and the absence of anomalous energy dissipation in the zero viscosity limit of solutions of the Navier-Stokes equation in the presence of no slip boundary condition.<br />
<br />
Eventually the above results are compared with several forms of a basic theorem of Kato in the presence of a Lipschitz solution of the Euler equations and one may insist on the fact that in such case the the absence of anomalous energy dissipation is {\bf equivalent} to the persistence of regularity in the zero viscosity limit. Eventually this remark contributes to the resolution of the d'Alembert Paradox.</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=PDE_Geometric_Analysis_seminar&diff=18145PDE Geometric Analysis seminar2019-10-11T18:57:33Z<p>Qinli: /* Abstracts */</p>
<hr />
<div>The seminar will be held in room 901 of Van Vleck Hall on Mondays from 3:30pm - 4:30pm, unless indicated otherwise.<br />
<br />
===[[Previous PDE/GA seminars]]===<br />
===[[Fall 2020-Spring 2021 | Tentative schedule for Fall 2020-Spring 2021]]===<br />
<br />
== PDE GA Seminar Schedule Fall 2019-Spring 2020 ==<br />
<br />
<br />
{| cellpadding="8"<br />
!style="width:20%" align="left" | date <br />
!align="left" | speaker<br />
!align="left" | title<br />
!style="width:20%" align="left" | host(s)<br />
|- <br />
|Sep 9<br />
| Scott Smith (UW Madison)<br />
|[[#Scott Smith | Recent progress on singular, quasi-linear stochastic PDE ]]<br />
| Kim and Tran<br />
|- <br />
|Sep 14-15<br />
| <br />
|[[ # |AMS Fall Central Sectional Meeting https://www.ams.org/meetings/sectional/2267_program.html ]]<br />
| <br />
|- <br />
|Sep 23<br />
| Son Tu (UW Madison)<br />
|[[#Son Tu | State-Constraint static Hamilton-Jacobi equations in nested domains ]]<br />
| Kim and Tran<br />
|- <br />
|Sep 28-29, VV901<br />
| https://www.ki-net.umd.edu/content/conf?event_id=993<br />
| | Recent progress in analytical aspects of kinetic equations and related fluid models <br />
| <br />
|- <br />
|Oct 7<br />
| Jin Woo Jang (Postech)<br />
|[[#Jin Woo Jang| On a Cauchy problem for the Landau-Boltzmann equation ]]<br />
| Kim<br />
|- <br />
|Oct 14<br />
| Stefania Patrizi (UT Austin)<br />
|[[#Stefania Patrizi | TBA ]]<br />
| Tran<br />
|- <br />
|Oct 21<br />
| Claude Bardos (Université Paris Denis Diderot, France)<br />
|[[#Claude Bardos | From d'Alembert paradox to 1984 Kato criteria via 1941 1/3 Kolmogorov law and 1949 Onsager conjecture ]]<br />
| Li<br />
|- <br />
|Oct 28<br />
| Albert Ai (UW Madison)<br />
|[[#Albert Ai | TBA ]]<br />
| Ifrim<br />
|- <br />
|Nov 4<br />
| Yunbai Cao (UW Madison)<br />
|[[#Yunbai Cao | TBA ]]<br />
| Kim and Tran<br />
|- <br />
|Nov 11<br />
| Speaker (Institute)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|- <br />
|Nov 18<br />
| Speaker (Institute)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|-<br />
|Nov 25<br />
| Mathew Langford (UT Knoxville)<br />
|[[#Speaker | TBA ]]<br />
| Angenent<br />
|- <br />
|- <br />
|Feb 17<br />
| Yannick Sire (JHU)<br />
|[[#Yannick Sire (JHU) | TBA ]]<br />
| Tran<br />
|- <br />
|Feb 24<br />
| Speaker (Institute)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|- <br />
|March 2<br />
| Theodora Bourni (UT Knoxville)<br />
|[[#Speaker | TBA ]]<br />
| Angenent<br />
|- <br />
|March 9<br />
| Ian Tice (CMU)<br />
|[[#Ian Tice| TBA ]]<br />
| Kim<br />
|- <br />
|March 16 <br />
| No seminar (spring break)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|- <br />
|March 23<br />
| Jared Speck (Vanderbilt)<br />
|[[#Jared Speck | TBA ]]<br />
| SCHRECKER<br />
|- <br />
|March 30<br />
| Speaker (Institute)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|- <br />
|April 6<br />
| Speaker (Institute)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|- <br />
|April 13<br />
| Speaker (Institute)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|- <br />
|April 20<br />
| Hyunju Kwon (IAS)<br />
|[[#Hyunju Kwon | TBA ]]<br />
| Kim<br />
|- <br />
|April 27<br />
| Speaker (Institute)<br />
|[[#Speaker | TBA ]]<br />
| Host<br />
|}<br />
<br />
== Abstracts ==<br />
<br />
===Scott Smith===<br />
<br />
Title: Recent progress on singular, quasi-linear stochastic PDE<br />
<br />
Abstract: This talk with focus on quasi-linear parabolic equations with an irregular forcing . These equations are ill-posed in the traditional sense of distribution theory. They require flexibility in the notion of solution as well as new a priori bounds. Drawing on the philosophy of rough paths and regularity structures, we develop the analytic part of a small data solution theory. This is joint work with Felix Otto, Hendrik Weber, and Jonas Sauer.<br />
<br />
<br />
===Son Tu===<br />
<br />
Title: State-Constraint static Hamilton-Jacobi equations in nested domains<br />
<br />
Abstract: We study state-constraint static Hamilton-Jacobi equations in a sequence of domains $\{\Omega_k\}$ in $\mathbb R^n$ such that $\Omega_k \subset \Omega_{k+1}$ for all $k \in \mathbb N$. We obtain rates of convergence of $u_k$, the solution to the state-constraint problem in $\Omega_k$, to $u$, the solution to the corresponding problem in $\Omega=\bigcup_k \Omega_k$. In many cases, the rates obtained are proven to be optimal (it's a joint work with Yeoneung Kim and Hung V. Tran).<br />
<br />
<br />
===Jin Woo Jang===<br />
<br />
Title: On a Cauchy problem for the Landau-Boltzmann equation<br />
<br />
Abstract: In this talk, I will introduce a recent development in the global well-posedness of the Landau equation (1936) in a general smooth bounded domain, which has been a long-outstanding open problem. This work proves the global stability of the Landau equation in an $L^\infty_{x,v}$ framework with the Coulombic potential in a general smooth bounded domain with the specular reflection boundary condition for initial perturbations of the Maxwellian equilibrium states. Our methods consist of the generalization of the well-posedness theory for the kinetic Fokker-Planck equation (HJV-2014, HJJ-2018) and the extension of the boundary value problem to a whole space problem, as well as the use of a recent extension of De Giorgi-Nash-Moser theory for the kinetic Fokker-Planck equations (GIMV-2016) and the Morrey estimates (BCM-1996) to further control the velocity derivatives, which ensures the uniqueness. This is a joint work with Y. Guo, H. J. Hwang, and Z. Ouyang.<br />
<br />
<br />
=== Claude Bardos ===<br />
Title: From the d'Alembert paradox to the 1984 Kato criteria via the 1941 $1/3$ Kolmogorov law and the 1949 Onsager conjecture<br />
<br />
Abstract: Several of my recent contributions, with Marie Farge, Edriss Titi, Emile Wiedemann, Piotr and Agneska Gwiadza, were motivated by the following issues:<br />
<br />
The role of boundary effect in mathematical theory of fluids mechanic and the similarity, in presence of these effects, of the weak convergence in the zero viscosity limit and the statistical theory of turbulence. <br />
<br />
As a consequence.<br />
<br />
<br />
I will recall the Onsager conjecture and compare it to the issue of anomalous energy dissipation.<br />
<br />
Then I will give a proof of the local conservation of energy under convenient hypothesis in a domain with boundary and give supplementary condition that imply the global conservation of energy in a domain with boundary and the absence of anomalous energy dissipation in the zero viscosity limit of solutions of the Navier-Stokes equation in the presence of no slip boundary condition.<br />
<br />
Eventually the above results are compared with several forms of a basic theorem of Kato in the presence of a Lipschitz solution of the Euler equations and one may insist on the fact that in such case the the absence of anomalous energy dissipation is {\bf equivalent} to the persistence of regularity in the zero viscosity limit. Eventually this remark contributes to the resolution of the d'Alembert Paradox.</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS/absF19&diff=18101Applied/ACMS/absF192019-10-04T13:59:36Z<p>Qinli: /* ACMS Abstracts: Fall 2019 */</p>
<hr />
<div>= ACMS Abstracts: Fall 2019 =<br />
<br />
=== Leonardo Andrés Zepeda Núñez ===<br />
<br />
Title: Deep Learning for Electronic Structure Computations: A Tale of Symmetries, Locality, and Physics<br />
<br />
Abstract: Recently, the surge of interest in deep neural learning has dramatically improved image and signal processing, which has fueled breakthroughs in many domains such as drug discovery, genomics, and automatic translation. These advances have been further applied to scientific computing and, in particular, to electronic structure computations. In this case, the main objective is to directly compute the electron density, which encodes most of information of the system, thus bypassing the computationally intensive solution of the Kohn-Sham equations. However, similar to neural networks for image processing, the performance of the methods depends spectacularly on the physical and analytical intuition incorporated in the network, and on the training stage.<br />
<br />
In this talk, I will show how to build a network that respects physical symmetries and locality. I will show how to train the networks and how such properties impact the performance of the resulting network. Finally, I will present several examples for small yet realistic chemical systems.<br />
<br />
<br />
=== Daniel Floryan (UW-Madison) ===<br />
<br />
Title: Flexible Inertial Swimmers<br />
<br />
Abstract: Inertial swimmers deform their bodies and fins to push against the water and propel themselves forward. The deformation is driven partly by active musculature, and partly by passive elasticity. The interaction between elasticity and hydrodynamics confers features on the swimmers not enjoyed by their rigid friends, for example, boosts in speed when flapping at certain frequencies. We explain the salient features of flexible swimmers by drawing ideas from airfoils, vibrating beams, and flags flapping in the wind. The presence of fluid drag has important consequences. We also explore optimal arrangements of flexibility. (It turns out that nature is quite good.)<br />
<br />
<br />
=== Jianfeng Lu (Duke) ===<br />
<br />
Title: How to ``localize" the computation?<br />
<br />
It is often desirable to restrict the numerical computation to a local <br />
region to achieve best balance between accuracy and affordability in scientific computing. It is important to avoid artifacts and guarantee predictable modelling while artificial boundary conditions have to be introduced to restrict the computation. In this talk, we will discuss some recent understanding on how to achieve such local computation in the context of topological edge states and elliptic random media.<br />
<br />
<br />
=== Mitch Bushuk (GFDL/Princeton) ===<br />
<br />
Title: Arctic Sea Ice Predictability in a Changing Cryosphere<br />
<br />
Abstract: Forty years of satellite observations have documented a striking decline in the areal extent of Arctic sea ice. The loss of sea ice has impacts on the climate system, human populations, ecosystems, and natural environments across a broad range of spatial and temporal scales. These changes have motivated significant research interest in the predictability and prediction of Arctic sea ice on seasonal-to-interannual timescales. In this talk, I will address two related questions: (1) What is the inherent predictability of Arctic sea ice and what physical mechanisms underlie this predictability? and (2) How can this knowledge be leveraged to improve operational sea ice predictions? I will present findings on the relative roles of the ocean, sea ice, and atmosphere in controlling Arctic sea ice predictability. I will also present evidence for an Arctic spring predictability barrier, which may impose a sharp limit on our ability to make skillful predictions of the summer sea ice minimum. <br />
<br />
<br />
=== Qin Li (UW-Madison) ===<br />
<br />
Title: The power of randomness in scientific computing<br />
<br />
Abstract: Most numerical methods in scientific computing are deterministic. Traditionally, accuracy has been the target while the cost was not the concern. However, in this era of big data, we incline to relax the strict requirements on the accuracy to reduce numerical cost. Introducing randomness in the numerical solvers could potentially speed up the computation significantly at small sacrifice of accuracy. In this talk, I'd like to show two concrete examples how this is done: first on random sketching in experimental design, and the second on numerical homgenization, hoping the discussion can shed light on potential other applications. Joint work with Ke Chen, Jianfeng Lu, Kit Newton and Stephen Wright.<br />
<br />
<br />
=== Joel Nishimura (Arizona State) ===<br />
<br />
Title: Random graph models with fixed degree sequences: choices, consequences and irreducibility proofs for sampling<br />
<br />
Abstract: Determining which features of an empirical graph are noteworthy frequently relies upon the ability to sample random graphs with constrained properties. Since empirical graphs have distinctive degree sequences, one of the most popular random graph models is the configuration model, which produces a graph uniformly at random from the set of graphs with a fixed degree sequence. While it is commonly treated as though there is only a single configuration model, one sampled via stub-matching, there are many, depending on whether self-loops and multiedges are allowed and whether edge stubs are labeled or not. We show, these different configuration models can lead to drastically, sometimes opposite, interpretations of empirical graphs. In order to sample from these different configuration models, we review and develop the underpinnings of Markov chain Monte Carlo methods based upon double-edge swaps. We also present new results on the irreducibility of the Markov chain for graphs with self-loops, either proving irreducibility or exactly characterizing the degree sequences for which the Markov chain is reducible. This work completes the study of the irreducibility of double edge-swap Markov chains (and the related Curveball Markov chain) for all combinations of allowing self-loops, multiple self-loops and/or multiedges. <br />
<br />
<br />
=== Alex Townsend (Cornell) ===<br />
<br />
Title: Why are so many matrices and tensors of low rank in computational mathematics?<br />
<br />
Abstract: Matrices and tensors that appear in computational mathematics are so often well-approximated by low-rank objects. Since random ("average") matrices are almost surely of full rank, mathematics needs to explain the abundance of low-rank structures. We will give various methodologies that allow one to begin to understand the prevalence of compressible matrices and tensors and we hope to reveal an underlying link between disparate applications. In particular, we will show how one can connect the singular values of a matrix with displacement structure to a rational approximation problem that highlights fundamental connections between polynomial interpolation, Krylov methods, and fast Toeplitz solvers.<br />
<br />
<br />
=== Prashant G. Mehta ===<br />
<br />
Title: What is the Lagrangian for Nonlinear Filtering?<br />
<br />
Abstract: There is a certain magic involved in recasting the equations in Physics, and the algorithms in Engineering, in variational terms. The most classical of these ‘magics’ is the Lagrange’s formulation of the Newtonian mechanics. An accessible modern take on all this and more appears in the February 19, 2019 issue of The New Yorker magazine: https://www.newyorker.com/science/elements/a-different-kind-of-theory-of-everything?reload=true <br />
<br />
My talk is concerned with a variational (optimal control type) formulation of the problem of nonlinear filtering/estimation. Such formulations are referred to as duality between optimal estimation and optimal control. The first duality principle appears in the seminal (1961) paper of Kalman-Bucy, where the problem of minimum variance estimation is shown to be dual to a linear quadratic optimal control problem. <br />
<br />
In my talk, I will describe a generalization of the Kalman-Bucy duality theory to nonlinear filtering. The generalization is an exact extension, in the sense that the dual optimal control problem has the same minimum variance structure for linear and nonlinear filtering problems. Kalman-Bucy’s classical result is shown to be a special case. During the talk, I will also attempt to review other types of duality relationships that have appeared over the years for the problem of linear and nonlinear filtering. <br />
<br />
This is joint work with Jin Won Kim and Sean Meyn. The talk is based on the following papers: https://arxiv.org/pdf/1903.11195.pdf and https://arxiv.org/pdf/1904.01710.pdf.<br />
<br />
<br />
=== Jean-Luc Thiffeault ===<br />
<br />
We consider a simple model of a two-dimensional microswimmer with fixed swimming speed. The direction of swimming changes according to<br />
a Brownian process, and the swimmer is interacting with boundaries. This is a standard model for a simple microswimmer, or a confined<br />
wormlike chain polymer. The shape of the swimmer determines the range of allowable values that its degrees of freedom can assume --- its<br />
configuration space. Using natural assumptions about reflection of the swimmer at boundaries, we compute the swimmer's invariant<br />
distribution across a channel consisting of two parallel walls, and the statistics of spreading in the longitudinal direction. This gives<br />
us the effective diffusion constant of the swimmer's large scale motion. When the swimmer is longer than the channel width, it cannot<br />
reverse, and we then compute the mean drift velocity of the swimmer. This model offers insight into experiments of scattering of swimmers<br />
from boundaries, and serves as an exactly-solvable baseline when comparing to more complex models. This is joint work with Hongfei Chen.</div>Qinlihttps://www.math.wisc.edu/wiki/index.php?title=Applied/ACMS&diff=18100Applied/ACMS2019-10-04T13:58:40Z<p>Qinli: /* Fall 2019 */</p>
<hr />
<div>__NOTOC__<br />
<br />
= Applied and Computational Mathematics Seminar =<br />
<br />
*'''When:''' Fridays at 2:25pm (except as otherwise indicated)<br />
*'''Where:''' 901 Van Vleck Hall<br />
*'''Organizers:''' [http://www.math.wisc.edu/~qinli/ Qin Li], [http://www.math.wisc.edu/~spagnolie/ Saverio Spagnolie] and [http://www.math.wisc.edu/~jeanluc Jean-Luc Thiffeault]<br />
*'''To join the ACMS mailing list:''' See [https://admin.lists.wisc.edu/index.php?p=11&l=acms mailing list] website.<br />
<br />
<br><br />
<br />
<br />
== Fall 2019 ==<br />
<br />
{| cellpadding="8"<br />
!align="left" | date<br />
!align="left" | speaker<br />
!align="left" | title<br />
!align="left" | host(s)<br />
|-<br />
| Sept 6<br />
|[http://math.mit.edu/~lzepeda/ Leonardo Andrés Zepeda Núñez] (UW-Madison)<br />
|''[[Applied/ACMS/absF19#Leonardo Andrés Zepeda Núñez (UW-Madison)|Deep Learning for Electronic Structure Computations: A Tale of Symmetries, Locality, and Physics]]''<br />
| Li<br />
|-<br />
| Sept 13<br />
|[http://dfloryan.mycpanel.princeton.edu/ Daniel Floryan] (UW-Madison)<br />
|''[[Applied/ACMS/absF19#Daniel Floryan (UW-Madison)|Flexible Inertial Swimmers]]''<br />
| Jean-Luc<br />
|-<br />
| Sept 14-15<br />
|[https://www.ams.org/meetings/sectional/2267_program.html AMS sectional meeting]<br />
| UW-Madison<br />
|-<br />
| Sept 20<br />
|[https://www.gfdl.noaa.gov/mitch-bushuk/ Mitch Bushuk] (GFDL/Princeton)<br />
|''[[Applied/ACMS/absF19#Mitch Bushuk (GFDL/Princeton)|Arctic Sea Ice Predictability in a Changing Cryosphere]]''<br />
| Chen<br />
|-<br />
| Sept 20 (colloquium, 4pm, B239)<br />
|[https://services.math.duke.edu/~jianfeng/ Jianfeng Lu] (Duke)<br />
|''[[Applied/ACMS/absF19#Jianfeng Lu (Duke)|How to "localize" the computation?]]''<br />
| Li<br />
|-<br />
| Sept 27<br />
|[http://www.math.wisc.edu/~qinli/ Qin Li] (UW-Madison)<br />
|''[[Applied/ACMS/absF19#Qin Li (UW-Madison)|The power of randomness in scientific computing]]''<br />
| host<br />
|-<br />
| Oct 4<br />
|[https://isearch.asu.edu/profile/2169104 Joel Nishimura] (Arizona State)<br />
|''[[Applied/ACMS/absF19#Joel Nishimura (Arizona State)|Random graph models with fixed degree sequences: choices, consequences and irreducibility proofs for sampling]]''<br />
| Cochran<br />
|-<br />
| Oct 11<br />
|[http://pi.math.cornell.edu/~ajt/ Alex Townsend] (Cornell)<br />
|''[[Applied/ACMS/absF19#Alex Townsend (Cornell)|Why are so many matrices and tensors of low rank in computational mathematics?]]''<br />
| Li<br />
|-<br />
| Oct 18<br />
|[http://mehta.mechse.illinois.edu/ Prashant G. Mehta] (UIUC)<br />
|''[[Applied/ACMS/absF19#Prashant G. Mehta (UIUC)|What is the Lagrangian for Nonlinear Filtering?]]''<br />
| Chen<br />
|-<br />
| Oct 25<br />
|[https://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault] (UW-Madison)<br />
|''[[Applied/ACMS/absF19#Jean-Luc Thiffeault|Shape matters: A Brownian microswimmer interacting with walls]]''<br />
| <br />
|-<br />
| Nov 1<br />
|[https://users.oden.utexas.edu/~tanbui/ Tan Bui] (UT-Austin)<br />
|''[[Applied/ACMS/absF19#Tan Bui (UT-Austin)|Title: TBA]]''<br />
| Li<br />
|-<br />
| Nov 8<br />
|[https://pan.labs.wisc.edu/staff/pan-wenxiao/ Wenxiao Pan] (UW)<br />
|''[[Applied/ACMS/absF19#Wenxiao Pan (UW)|TBA]]''<br />
| Spagnolie<br />
| <br />
|-<br />
| Nov 15<br />
|[https://www.math.wisc.edu/~pgera/ Prerna Gera] (UW)<br />
|''[[Applied/ACMS/absF19#Prerna Gera (UW)|TBA]]''<br />
| Spagnolie<br />
|-<br />
| Dec 6<br />
|[https://math.berkeley.edu/~linlin/ Lin Lin] (Berkeley)<br />
|''[[Applied/ACMS/absF19#Lin Lin (UC Berkeley)|TBA]]''<br />
| Li<br />
|-<br />
|}<br />
<br />
== Future semesters ==<br />
<br />
*[[Applied/ACMS/Spring2020|Spring 2020]]<br />
<br />
== Archived semesters ==<br />
*[[Applied/ACMS/Spring2019|Spring 2019]]<br />
*[[Applied/ACMS/Fall2018|Fall 2018]]<br />
*[[Applied/ACMS/Spring2018|Spring 2018]]<br />
*[[Applied/ACMS/Fall2017|Fall 2017]]<br />
*[[Applied/ACMS/Spring2017|Spring 2017]]<br />
*[[Applied/ACMS/Fall2016|Fall 2016]]<br />
*[[Applied/ACMS/Spring2016|Spring 2016]]<br />
*[[Applied/ACMS/Fall2015|Fall 2015]]<br />
*[[Applied/ACMS/Spring2015|Spring 2015]]<br />
*[[Applied/ACMS/Fall2014|Fall 2014]]<br />
*[[Applied/ACMS/Spring2014|Spring 2014]]<br />
*[[Applied/ACMS/Fall2013|Fall 2013]]<br />
*[[Applied/ACMS/Spring2013|Spring 2013]]<br />
*[[Applied/ACMS/Fall2012|Fall 2012]]<br />
*[[Applied/ACMS/Spring2012|Spring 2012]]<br />
*[[Applied/ACMS/Fall2011|Fall 2011]]<br />
*[[Applied/ACMS/Spring2011|Spring 2011]]<br />
*[[Applied/ACMS/Fall2010|Fall 2010]]<br />
<!--<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring10.html Spring 2010]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall09.html Fall 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring09.html Spring 2009]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall08.html Fall 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring08.html Spring 2008]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall07.html Fall 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Spring07.html Spring 2007]<br />
*[http://www.math.wisc.edu/~jeanluc/ACMS/archive/Fall06.html Fall 2006]<br />
--><br />
<br />
<br><br />
<br />
----<br />
Return to the [[Applied|Applied Mathematics Group Page]]</div>Qinli