|
Screening of "Top Secret Rosies: The Female Computers of WWII" |
| Abstract: This documentary tells the story of four women 'computers', presenting their exhilarating successes in aiding the war effort and the moral dilemmas they faced. WWII ushered in a new era for women in the workforce, including female mathematicians. In 1942, the United States military began recruiting college-educated female mathematicians to work as human 'computers'. Equipped with desktop calculators and a Differential Analyzer (a predecessor to the world's first electronic computer), these women computed firing tables which improved the accuracy and effectiveness of the Allies' weapons. Working 6 days a week, 24 hours a day from a lab at the University of Pennsylvania, the women were considered sub-professionals and paid only $2000 a year, but their efforts had profound effects on the war and on the dawn of computer programming.This event is sponsored by IMA and NSF and organized by Irina Mitrea, Alexandra Ortan, and Katharine Ott. |
| Aycil Cesmelioglu (University of Minnesota) |
On the coupling of surface/subsurface flow with transport |
| Abstract: The coupling of porous media flow with free flow arises in many applications an example of which is groundwater contamination through rivers. The free flow is characterized by the Navier-Stokes equations whereas the porous media flow is described by the Darcy equations. Beavers-Joseph-Saffman interface condition is prescribed at the interface separating two regions. A transport equation for the contaminant concentration is fully coupled to the flow problem via the velocity field and the viscosity.
First, we discuss the existence result to the related weak formulation of the full coupling problem. Second, we analyze numerical schemes based on classical finite element methods and discontinuous Galerkin methods for the special case where the coupling is only one-way, that is, the velocity field from the Navier-Stokes/Darcy problem is an input
for the transport equation. Numerical solutions for non homogeneous porous media are also presented. |
| Clint Dawson (University of Texas at Austin) |
Tutorial Lectures: Modeling Hurricane Storm Surges - Lecture 2: The numerical approximation of the shallow water equations
|
| Abstract: I will discuss the predominant methods used to approximate solutions to the shallow water equations, including staggered finite difference methods, finite element and finite volume methods. Pros and cons of the different approaches will be discussed.
|
| Clint Dawson (University of Texas at Austin) |
Tutorial Lectures: Modeling Hurricane Storm Surges - Lecture 3: Applications of the shallow water equations, including hurricane storm surges
|
| Abstract: I will discuss various applications where large-scale shallow water simulators are used, and focus on modeling coastal inundation due to hurricane storm surges. |
| Sathiya Keerthi (Yahoo! Inc.) |
Large scale information extraction from the web |
| Abstract: The web has a vast wealth of information about various types of entities such as businesses (e.g., address, phone, category, hours of operation), products, books, doctors, etc. distributed over a very large number of web sites. Extracting this information from the websites can help us create extensive databases of the entities. These databases can then be used by search engines for better ranking and rendering of search results, e.g., a user can search for products with certain features. The websites usually contain the information in semi-structured formats which are varied and noisy. Extraction on a large scale is challenging because it is not feasible to provide supervision (say, via labeled examples) on a per site basis. In this talk I will give an overview of all the steps associated with a complete extraction pipeline and describe a few scalable machine learning approaches for large scale information extraction.Bio:
Dr. Keerthi is a Principal Research Scientist in Yahoo! Research. Over the last twenty years his research has focused on the development of practical algorithms for a variety of areas, such as machine learning, robotics, computer graphics and optimal control. His works on support vector machines (fast algorithms), polytope distance computation (GJK algorithm) and model predictive control (stability theory) are highly cited. His current research focuses on machine learning algorithms for structured outputs as applied to information extraction. Prior to joining Yahoo!, he worked for 10 years at the Indian Institute of Science, Bangalore, and for 5 years at the National University of Singapore. Dr. Keerthi is a member of the editorial board of Journal of Machine Learning Research.
|
| Hengguang Li (University of Minnesota) |
FEMs and MG methods for axisymmetric problems |
| Abstract: We shall discuss finite element and multigrid techniques solving the axisymmetric Poisson's equation and the azimuthal Stokes problem on polygonal domains with possible singular solutions. In particular, we construct stable interpolation operators and establish the well-posedness and regularity in some weighted Sobolev space, which in turn, leads to special finite element spaces to approximate the solutions in the optimal rate. With a careful formulation, we also obtain uniform convergence of the MG methods. These estimates can also be used to show the stability of the Taylor-Hood elements for the axisymmetric Stokes problem and to precondition the indefinite system from the axisymmetric Stokes equations. |
| Lalit K. Mestha (Xerox Research Center, Webster) |
Role of signals and systems theory in solutions and services business |
| Abstract: In this talk, we present how signals and system theory was used for creating novel color solutions for digital production printing. We describe the system, mathematical formulation of the process, use of specialized algorithms, methods and architectures briefly, and then present focused research topics we are working on for transportation and healthcare systems. Integration of modern theories (e.g, compressed sensing, control & optimization theory), specialized optics with various imaging devices in the visible and infrared red wavelength bands will be presented aimed at creating next generation solutions and services business. |
| Weifeng (Frederick) Qiu (University of Minnesota) |
An hp DPG method for linear elasticity with symmetric
stresses |
Abstract: Joint work with Jamie Bramwell 3, Leszek Demkowicz
2, and Jay
Gopalakrishnan 1.
In this research, we present two Discontinuous Petrov-Galerkin
(DPG) finite element
methods for linear elasticity. For the first method, we
consider asymmetric test tensors for the
constitutive equation and compute infinitessimal rotations,
while in the second method we
only use symmetric test tensors and therefore have fewer
unknowns. We define optimal test
functions which are shown to deliver the best approximation
error if an optimal global test
norm is used. To make the method practical, we show a
localizable test norm is equivalent
to the global optimal norm. The majority of this proof is the
verification that the inf-sup
condition holds for our DPG formulations using the localizable
test space norm. From DPG
theory, this proves our methods are quasi-optimal with
constants independent of the mesh.
We can then use results from approximation theory to show
h and
p convergence for both
methods.
Since the quasi-optimal test space norm is localizable, we have
implemented practical
finite element codes that show h and p convergence of both
methods at optimal rates. Additionally, the DPG framework provides an a priori error
estimator determined by a local
auxilliary variational problems. We use this estimator as the
basis for various 'greedy' adaptive schemes. We test our adaptive algorithm using a
manufactured smooth solution as well
as a singular solution L-shape domain problem and observe
adaptive h and hp convergence.
The principal contributions of this research are proving
p
convergence for the dual-mixed
elasticity system, particularly without the need for a discrete
exact sequence or commuting
diagram, as well as a practical adaptive 2D elasticity code
with a priori error estimation.
We will present an overview of the theoretical DPG framework,
the convergence proofs for
both methods, and the numerical results for both a singular and
smooth solution.
References
- J. Bramwell, L. Demkowicz, and W. Qiu. Solution of
Dual-Mixed Elasticity Equations
using Arnold-Falk-Winther Element and Discontinuous
Petrov-Galerkin Method, a Comparison. Technical Report 10-23, The Institute for
Computational Engineering and Sciences, The University of Texas at Austin, June 2010.
- J. Bramwell, L. Demkowicz, J. Gopalakrishnan, and W. Qiu.
An hp DPG Method for
Linear Elasticity with Symmetric Stresses, in preparation.
1 Professor, Mathematics, University of Florida
2 Professor, Institute for Computational Engineering and
Sciences,
3 Graduate Research Assistant, Institute for Computational
Engineering and Sciences,
University of Texas at Austin
|
