[grads] [Sem-coll] Applied Math Colloquia & Seminars 3/2-3/6
Joe Millham
jmillhamiit at gmail.com
Thu Feb 26 15:36:47 CST 2009
Please join the IIT Applied Math department for the following seminars
and colloquia. All are welcome to attend, and refreshments will be
served at some events. For an updated schedule of events, please
check the schedule online <http://www.iit.edu/csl/am/colloquia/>.
Department Colloquium
Monday, March 2 E1 106 4:40 pm
Lexing Ying
University of Texas at Austin
"Butterfly Algorithm and Its Applications"
see abstract below
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Department Colloquium
Tuesday, March 3 E1 103 4:40 pm
Pawel Pralat
Dalhousie University
"Cleaning Regular Graphs with Brushes and Brooms"
see abstract below
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Department Colloquium
Thursday, March 5 E1 242 4:40 pm
Guohui Song
Syracuse University
"Optimal Kernel for Machine Learning"
see abstract below
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Department Colloquium
Friday, March 6 E1 106 4:40 pm
Esther Widiasih
University of Minnesota
"How Iceline Moves: Revisiting Budyko's Energy Balance Model"
see abstract below
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Department Colloquium
Monday, March 2 E1 106 4:40 pm
Lexing Ying
University of Texas at Austin
"Butterfly Algorithm and Its Applications"
Oscillatory integral transforms and equations arise in many direct and
inverse problems pertaining to wave propagation phenomena. Examples
abound in fields including seismic migration, acoustic and
electromagnetic wave scattering, and radar imaging. However, the rapid
evaluation of these transforms is an challenging task due to the
oscillatory nature of the kernel.
In this talk, we first review the butterfly algorithm, which was
recently developed as a general approach for the rapid evaluation of
these oscillatory integrals. However, sometimes the practical
efficiency of the butterfly algorithm is limited by its high
preprocessing time and high storage requirement. In the second part of
this talk, we discuss two applications: (1) sparse Fourier transform
and (2) partial Fourier transform, where in each case these
constraints can be removed by using tools such as tensor product
decomposition and non-standard Chebyshev interpolation.
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Department Colloquium
Tuesday, March 3 E1 103 4:40 pm
Pawel Pralat
Dalhousie University
"Cleaning Regular Graphs with Brushes and Brooms"
A model for cleaning a graph with brushes was recently introduced. We
consider the minimum number of brushes needed to clean d-regular
graphs in this model, focusing on the asymptotic number for random
d-regular graphs.
We use a degree-greedy algorithm to clean a random d-regular graph on
n vertices (with dn even) and analyze it using the differential
equations method to find the (asymptotic) number of brushes needed to
clean a random d-regular graph using this algorithm (for fixed d). We
further show that for any d-regular graph on n vertices at most
n(d+1)/4 brushes suffice, and prove that for fixed large d, the
minimum number of brushes needed to clean a random d-regular graph on
n vertices is asymptotically almost surely n/4(d+o(d)).
+++++++++++++++++++++++++++++++++++++
Department Colloquium
Thursday, March 5 E1 242 4:40 pm
Guohui Song
Syracuse University
"Optimal Kernel for Machine Learning"
Motivated by learning the target function from observed data with
kernels, a selection criterion for the optimal kernel is proposed. To
reduce the computation cost, we approximate the full kernel matrix in
the cost functional by a circulant matrix. The approximation
convergence
is discussed and some specific kernels such as Gaussian kernels and
B-spline kernels are investigated as examples.
This is joint work with my advisor Professor Yuesheng Xu at Syracuse University
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Department Colloquium
Friday, March 6 E1 106 4:40 pm
Esther Widiasih
University of Minnesota
"How Iceline Moves: Revisiting Budyko's Energy Balance Model"
An Energy Balance Model (EBM) is an example of a conceptual climate
model, constructed to build an understanding of the ice albedo
feedback mechanism. In this talk, I will start with an EBM, originated
by Mihail Budyko in 1969, and formulated by Ka Kit Tung in 2007. Then
I will propose a new formulation which includes a mechanism admitti e
line and which leads to new results.
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See you there!
Joe Millham
Administrative Assistant
Department of Applied Mathematics
Illinois Institute of Technology
Engineering-1 Room 208
10 W. 32rd St.
Chicago IL 60616
312.567.8984 (Phone)
312.567.3135 (Fax)
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