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Upcoming Seminars
MONDAY, April 14, 2008
GRADUATE STUDENT RESEARCH SEMINAR PSA 103 12:00 p.m.
Lydia Bilinsky, Department of Mathematics and Statistics
"Impact of Quiescence on Predator-Prey Dynamics"
ABSTRACT: The classical MacArthur-Rosenzweig predator-prey
model has a stable limit cycle if prey carrying capacity is
large and/or predator mortality is small. We have shown that the
introduction of a quiescent phase for the prey and/or the
predator can result in collapse of the limit cycle to a stable
coexistence steady state; the exact stability domain is
determined. Even when quiescence has not eliminated the limit
cycle, numerical studies suggest that the limit cycle has
shrunk. Implications of these findings for species conservation
will be discussed.
Bagels and juice will be served in PSA 103 at 11:50 a.m.
TUESDAY, April 15, 2008
MATHEMATICS AND COGNITION SEMINAR PSA 206 12:15 p.m.
Paolo Frasca, Politecnico di Torino
"Average Consensus by Gossip Algorithms with Quantized
Communication"
ABSTRACT: A randomized gossip algorithm can solve the average
consensus problem on networks with quantized communications.
The algorithm is proved to converge to the average value, up to
the size of the quantization bins, whenever the graph is
connected. Moreover, its speed of convergence is estimated.
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 16, 2008
STATISTICS SEMINAR PSA 206 10:40 a.m.
Burke Grandjean, University of Wyoming
"Statistical Issues in Estimating 'Willingness to Pay' from
Survey Data"
ABSTRACT: Contingent Valuation surveys assess the public's
willingness to pay (WTP) for goods or services in the absence
of direct market information. Policymakers in the U.S. and
elsewhere have used the resulting value estimates to guide
their decisions on topics like water quality protection, air
quality improvement, watershed and ecosystem protection, and
reduced human health risk. A recent national telephone survey
assessed WTP for a new pass to U.S. national forests, national
parks, and other federal lands. Computer-Aided Telephone
Interviewing (CATI) was a cost-effective approach for this
large-scale, time-constrained policy study. CATI is especially
well-suited for randomizing a range of prices to ask
respondents about their WTP. The research design also allowed a
probit analysis contrasting the hypothetical purchasing
decisions of respondents with actual purchasing decisions of an
existing, almost identical pass. The total hypothetical bias
found in a sample of the U.S. general population (sampled via
Random Digit Dialing) implies that pass revenues estimated
directly from the survey responses would be higher than actual
revenues by a factor of 16. The total hypothetical bias in a
sample of recent pass purchasers (a listed sample from the
National Parks Foundation) is much lower and even slightly
negative. This supports research showing that market experience
helps people to state accurately their true valuation for
public and environmental goods.
FIRST YEAR MATHEMATICS SEMINAR ECA 225 1:40 p.m.
Eric Kennedy, Department of Mathematics and Statistics
"The Newest Member of the Virtual Age: Instructor Office
Hours"
ABSTRACT: From IMs to avatars, iPhones to iPods, [WINDOWS-
1252?] today's youth are more tech savvy than ever before. As
these students become more reliant on technology to mediate
their interactions with others (email, cell phones, text
messages, MySpace), educators must devise new ways to reach
their audience. In August 2007, I started offering Virtual
Office Hours for my MAT 142 Online students using a program
called Adobe Connect. This program, which is licensed through
ASU, allows for a fully interactive virtual environment.
Student questions, which are typed in an instant messaging-
style window, are answered both verbally (using a microphone)
and visually (using a webcam).Customizable windows allow
instructors to share files, poll students, send private
messages, and manage the attendees.
Furthermore, sessions can be recorded and made available to
those who were unable to attend. While designed originally as
a platform for businesses to host online meetings, I have found
the program to also be an excellent tool for online Q&A
sessions with students. After the successful implementation
last fall, the Adobe Connect software is now being piloted by
the entire MAT 142 Online team.
In this talk we will discuss the setup required to host
Virtual Office Hours, and then explore the functionalities
available in the online environment.
NUMBER THEORY SEMINAR PSA 308 1:40 p.m.
Keenan Kidwell, Department of Mathematics and Statistics
"The Theory and Computation of Finite Extensions of The
p-adic Numbers, II"
ABSTRACT: The fields of real and p-adic numbers are examples of
local fields, (locally compact topological fields), and are the
only completions of Q, while number fields (finite extensions
of Q) are examples of global fields. The number theoretic
motivation for studying the properties of real and p-adic
numbers is to obtain local information, which (hopefully) can
be assembled into global information about number fields; an
example of the success of this strategy is the Hasse-Minkowski
Theorem, a local-global principle relating the existence of
zeros of quadratic forms over the real and p-adic numbers to
that of zeros over the rationals. One connection between number
fields and p-adic fields is given by the so-called p-adic
algebra of a number field F:
F \otimes Qp \cong \prod_{i=1}^g K_{p,i}, where each K_{p,i}
is a finite extension of the p-adic numbers. Within a fixed
algebraic closure, there are only finitely many extensions of
the p-adic numbers of a given degree. In this two-part talk, we
will discuss the theoretical aspects of p-adic fields,
including residue degree, ramification index, unramified and
totally ramified extensions, the continuity of roots of
polynomial equations, and the aforementioned finiteness result,
as well as some of the work of J. Jones and D. Roberts
involving the determination and classification of the
extensions of the p-adic numbers of a given degree.
THURSDAY, April 17, 2008
PH.D. DISSERTATION DEFENSE PSH 132 12:00 p.m.
Vicki Sealey, Department of Mathematics and Statistics
"Calculus Students' Assimilation of the Riemann Integral into
a Previously Established Limit Structure"
ABSTRACT: This research examines calculus students'
understanding of Riemann sums and definite integrals. Piaget's
structuralism was used as the theoretical perspective for the
design of the study as well as the data analysis. Structuralism
is a form of constructivism that is based on the idea that
students "construct" understanding by engaging in activities
that promote the development of a structure, in this case the
structure of the Riemann integral. A teaching experiment was
designed to develop students' understanding of the structure of
the Riemann sum definition of the definite integral via
assimilation into a previously established limit structure.
This research seeks to understand the development of
students' cognition when engaging in activities that require
the use of Riemann sums or definite integrals. It also
identifies common obstacles that students encounter when
working with Riemann integrals, including ways in which the
students overcome these obstacles. Finally, the research seeks
to evaluate aspects of curriculum and instructional design that
were used in the teaching experiment.
Data consisted of students' written work, videotapes of
students working on various activities during class time, and
clinical interviews conducted during the semester following
the teaching experiment. Data was analyzed using the principles
of grounded theory along with a preliminary framework developed
by the author. The framework was used for initial coding, and
then patterns and relationships between the categories were
evaluated.
The framework describes the mathematical structure of the
Riemann sum definition of the definite integral in five layers:
a pre-layer involving sense-making, a product layer, a
summation layer, and a limit layer. The framework is an initial
cognitive framework that was based on the mathematical
decomposition of the definite integral and the research on its
components and has become a way to understand students'
cognitive development as they develop the structure of the
Riemann integral. As the framework was revised, it has become a
contribution to both the teaching community and the research
community in that it allows us to understand how students
reason about Riemann sums and definite integrals.
NATIONAL MATHEMATICS AWARENESS MONTH
MOVIE NIGHT
On the South wall of the Art Museum (FAC Plaza) 7:00 p.m.
(Presented by the ASU SIAM chapter)
"Stand and Deliver"
STARRING: Edward James Olmos, Lou Diamond Phillips, Rosanna de
Soto, Andy Garcia. DIRECTOR: Ramon Menendez.
SYNOPSIS: Edward James Olmos portrays the real-life Jaime
Escalante, a no-nonsense mathematic teacher in a tough East LA
high school. Handed a classroom full of "losers" and
"unteachables," Escalante is determined to turn his young
charges' lives around. Drawing from his own cultural heritage,
Escalante forms a bond with his largely Hispanic student body,
evoking the names of famous Spaniards and Latin Americans whose
great accomplishments were predicated on their ability to
learn. The students gradually come to realize that the only way
they'll escape their own poverty-stricken barrio is to improve
themselves intellectually. As a result, the class' academic
achievements soar dramatically - too dramatically for the
Educational Testing Service, which is convinced that the class'
high test scores are the results of cheating. The triumphant
exoneration of Escalante's students provides Stand and Deliver
with its rousingly upbeat conclusion. ~ Hal Erickson, All Movie
Guide
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.
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