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Upcoming Seminars
FRIDAY, April 18, 2008
MATH BIOLOGY SEMINAR ECG 237 2:00 p.m.
Yi Li, University of Iowa
"Stability of Traveling Waves with Noncritical Speeds for
Double Degenerate Fisher-Type Equations"
ABSTRACT: This talk is concerned with the asymptotic stability
of traveling wave solutions for double degenerate Fisher-type
equations. By detailed spectral analysis, each traveling front
solution with non-critical speed is proved to be linearly
exponentially stable in some exponentially weighted spaces.
Further by Evans function method and detailed semi-group
estimates, each traveling wave solution with noncritical speed
is proved to be locally algebraically stable to perturbations
in some appropriate polynomially weighted spaces.
Joint work with Yaping Wu, Capital Normal University.
Coffee and cookies will be served in PSA 546 at 3:00 p.m.
C*-ALGEBRA SEMINAR PSA 307 2:40 p.m.
Dorin Dumitrascu, University of Arizona
MATH BIOLOGY SEMINAR ECG 237 3:40 p.m.
Paul-Leonard Salceanu, Department of Mathematics and Statistics
"Persistence in a Discrete-time, Stage-structured Epidemic
Model"
ABSTRACT: Discrete-time SI and SIR epidemic models, formulated
by Emmert and Allen, for the spread of a fungal disease in a
structured amphibian host population, are analyzed. Criteria
for persistence of the population as well as for persistence of
the disease are established. Global stability results for host
extinction and for the disease-free equilibrium are presented.
UNDERGRADUATE GEOMETRY AND CONTROL SEMINAR ECG 319 3:40 p.m.
Matthias Kawski, Department of Mathematics and Statistics
"From Hamilton to Pontryagin's Maximum Principle"
ABSTRACT: Following an article by Sussmann and Willems titled
"300 years of optimal control..." written on the occasion of
the 300'th birthday of Johann Bernoulli's solution of the
brachystochrone problem, we discuss connections and disparities
between the classical calculus of variations and modern optimal
control. Key items are: what does the q in (d/dt)(dL/d qdot)
mean, and how close were Hamilton & Co to modern mathematics
when they made some poor choices that held back the field for
almost a century?
This seminar is geared towards advanced undergraduates,
especially those with a working knowledge of mechanics, and who
might be interested in a modern course on differential geometry
and control.
TUESDAY, April 22, 2008
MATHEMATICS AND COGNITION SEMINAR PSA 206 12:15 p.m.
PANEL DISCUSSION WITH:
Rachel Levinson, Biodesign Institute
Jeremy Rowe, School Computing & Informatics
Dan Sarewitz, Consortium for Science, Policy and Outcomes
Douglas Sylvester, Sandra Day O'Connor College of Law
"The End of Privacy"
ABSTRACT: The luxury of privacy as we have known it is, rather
suddenly, no longer possible. Those who have access to our
private lives include the government, private companies, a wide
range of information brokers and individuals. The recent rapid
advances in technology which have enabled the ability to
know so much about us include computationally enabled
communications, chemical and biological sensors, positioning,
signal and image processing, statistics, pattern extraction and
recognition as well as modeling and dynamical systems, all
contribute and have contributed to the extinction of privacy.
The illusion that it is still possible to possess privacy is
widespread, however. The goal of this panel discussion is to
illuminate a situation which is uncomfortable to many and to
consider the implications of this alteration in our social
environment in terms of policy, law, ethics and personal choice.
Reading resources and panelists' biographies:
http://math.la.asu.edu/~tom/cognition/PrivacyAbstrS08.html
This panel discussion is sponsored in part by the Templeton
Research Lectures at ASU -"Facing the Challenges of
Transhumanism: Religion, Science, Technology"
(www.asu.edu/transhumanism/)
Cookies and coffee will be served at 12:00 p.m.
APPLIED ANALYSIS AND PDE READING SEMINAR PSA 546 3:00 p.m.
For more information, contact Svetlana Roudenko.
WEDNESDAY, April 23, 2008
PH.D. DISSERTATION DEFENSE SS 236 11:00 a.m.
Guoyi Zhang, Department of Mathematics and Statistics
"Smoothing Splines Using Compactly Supported, Positive
Definite, Radial Basis Functions"
ABSTRACT: In the context of nonparametric regression, spline
smoothing is one of the most useful tools. The statistical
properties of smoothing splines are now fairly well understood
and we have seen enormous applications of smoothing splines in
myriad different disciplines during the past twenty years.
Smoothing splines have many attractive properties when compared
with other nonparametric function estimation methods. In
particular, smoothing splines are the most efficient method
from a computational perspective for the one dimensional case.
This property is a consequence of the band matrices that arise
in the normal equation system for the smoother. However, the
currently popular generalized smoothing splines that are used
in high dimensional settings do not have this property which
makes them computationally slow and difficult to use with large
data sets. In this research, we derived a smoothing spline
estimator for use in multivariate regression and constructed a
fast algorithm for its computation. To accomplish this, we
employ general concepts associated with roughness penalty
methods in conjunction with the theory of radial basis
functions and reproducing kernel Hilbert spaces. It is shown
that through the use of compactly supported radial basis
functions it becomes possible to recover the band structured
matrix aspect of spline smoothing and thereby obtain a fast
computational algorithm. The algorithm is implemented in C++ in
both serial and parallel computing environments. The latter
context also involves some preliminary use of domain
decomposition for spline smoothing with large multivariate data
sets.
FIRST YEAR MATHEMATICS SEMINAR ECA 217 1:40 p.m.
Marta Pecuch-Herrero, Department of Mathematics and Statistics
"Origami and Mathematics Education:
An Overview and a Workshop"
ABSTRACT: In recent years, there has been a significant
increase in the number of applications of origami to science,
technology, and education, in addition to mathematical research
in origami. Origami is being used as an auxiliary tool for
teaching mathematics in several countries and at many different
levels, from elementary school to college. In this talk I will
present an overview of current use of origami as well as
concrete examples that participants in the workshop will be
able to fold. Origami paper will be provided.
NUMBER THEORY SEMINAR PSA 308 1:40 p.m.
Dong Quan Nguyen, Department of Mathematics and Statistics
"On the Duffin-Schaeffer Conjecture, Part I"
ABSTRACT: We will prove the Duffin-Schaeffer theorem, which
motivates the formulation of the Duffin-Schaeffer conjecture.
THURSDAY, April 24, 2008
COMPUTATIONAL AND APPLIED MATHEMATICS
PROSEMINAR PSA 206 12:15 p.m.
Wolfgang Stefan, Department of Mathematics and Statistics
"Improved Total Variation-Type Regularization Using
Higher-Order Edge Detectors"
ABSTRACT: We present a novel deconvolution approach that
simultaneously deblurs and detects edges in piecewise smooth
signals. Both edges and smooth regions, separated by jump
discontinuities, are preserved. The method uses a two step
procedure: The polynomial annihilation method combined with
total variation (TV) deconvolution obtains an estimate of the
location of jump discontinuities in blurred noisy data. This
information is used to determine the order for a higher-order
TV regularization which is then utilized in the signal
restoration. As compared to those obtained with standard TV,
signal restorations are more accurate representations of the
true signals, as measured in a relative l^{2} norm, and can
also be used to obtain a more accurate estimation of the
locations and sizes of the true jump discontinuities.
NATIONAL MATHEMATICS AWARENESS MONTH
COLLOQUIUM PSA 106 3:40 p.m.
Francis Su, Harvard Mudd College
"Splitting the Rent, Keeping the Peace:
Fairness Problems and Fixed Points"
ABSTRACT: How do you divide the rent among roommates fairly? My
friend's dilemma was a question that mathematics could answer,
both elegantly and constructively. We show how it and other
"fair division" questions -- the most famous of which is the
problem of Steinhaus: how do you cut a cake fairly? -- motivate
a host of "combinatorial fixed point theorems" and problems
about polytopes. They provide excellent examples of how
mathematics can address an old class of problems in new ways,
and conversely, how problems in the social sciences can
motivate new mathematics -- where topology, geometry, and
combinatorics meet social applications, and where research by
undergraduates has played a big role.
Refreshments will be served in PSA 206 at 3:15 p.m.
FRIDAY, April 25, 2008
MATH BIOLOGY SEMINAR ECG 237 3:40 p.m.
Carole Baskin, Biodesign Institute
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