March 01 ■ 4 p.m. - 5 p.m. UP 117 (Southern
Methodist University, Dallas, Texas, U.S.A. ) Hon Keung Tony Ng Title: Analysis
of System-based Reliability Data Abstract: In
system reliability engineering, systems are made up of different components and
these systems can be complex. For various purposes, engineers and researchers
are often interested in the lifetime distribution of the system as well as the
lifetime distribution of the components which make up the system. In many cases,
the lifetimes of an n-component
coherent system can be observed, but not the lifetimes of the components. In
the recent years, parametric and nonparametric inference for the lifetime
distribution of components based on system lifetime lifetimes has been
developed. We further investigate the estimation of the parameters in component
lifetime distributions based on censored system-level data. Specially, we
consider the maximum likelihood estimation and propose alternative
computational methods and approximations to the maximum likelihood estimators.
Based on the special features of the system lifetime data, we treat the system
lifetime data as incomplete data and apply the Expectation-Maximization (EM)
algorithm to obtain the MLEs and apply the stochastic EM (SEM) algorithm to
approximate the MLEs. Different implementations of the EM and SEM algorithms
are proposed and their performances are evaluated. We have shown that the
proposed methods are feasible and easy to implement for various families of component
lifetime distributions.
March 15 4 p.m. - 5 p.m. UP 117■ Cindy Yu (Iowa State University)Title: Generalized Method of Moments Estimator Based On Semiparametric Quantile Regression
Imputation Abstract:
In this talk, we consider an imputation method to handle missing
response values
based on semiparametric quantile regression estimation. In the proposed
method, the missing response values are generated using the estimated
conditional quantile regression function at given values of covariates.
We adopt the generalized method of moments
for estimation of parameters defined through a general estimation
equation. We demonstrate that the proposed estimator, combining both
semiparametric quantile regression imputation and generalized method of
moments, is an effective alternative to parameter
estimation when missing data is present. The consistency and the
asymptotic normality of our estimators are established and variance
estimation is provided. Results from limited simulation studies are
presented to show the adequacy of the proposed method. March 23 4 p.m. - 5 p.m. UP 117■ Elizabeth Arnason (USD)Title: Matrix Population Models Abstract: Oftentimes in biology, there are questions regarding the future of
populations. Projection matrices can be utilized to solve such problems. These
models neatly summarize the structure of the population, which can be found
using the population’s life cycle graph. In this talk, we will discuss the
different structures of these matrices. The structure chosen is dependent on
the attributes of the population in question. Once the model is constructed,
mathematical methods can be applied to obtain important information regarding
the population. This information can be used to make informed management
decisions.April 10 4 p.m. - 5 p.m. UP 117■ Jessie Byrnes (USD)Title:
Bayesian Estimate of Stress-Strength Parameter for Burr Type XII
Distribution Based on Progressively First Failure-Censored Samples Abstract:
In industry, the lifetimes of components are becoming longer due to
rapid advances in manufacturing technology and a sustained quality
improvement effort. Therefore, practitioners are encouraged to adopt
some type of censoring scheme in lifetime testing in order to save time
and money. From the censored data, statistical techniques can be applied
to infer a product’s reliability.For this presentation, the progressive first failure-censoring scheme is used to obtain samples from two Burr Type XII distributions respectively, so that the stress-strength parameter can be inferred. This reliability parameter is evaluated under Bayesian estimation because it lacks a closed form solution under maximum likelihood estimation. Because of computation complexities and no closed forms of estimators, Markov Chain Monte Carlo procedure is proposed for a simulation study. From the simulation results, the Bayesian estimator under a given loss function will be discussed. Keywords: Lifetime Censoring; Burr Type XII; Stress-strength Parameter; Bayesian Estimate; Markov Chain Monte Carlo Algorithm April 26 4 p.m. - 5 p.m. UP 117■ Jyun-You Chiang (Southwestern University of Finance and Economics, China)Title: Economic design of two-stage semicircle control chart for dependent variables Abstract: Link to abstractFall 2016October 17 ■ 4 p.m. - 5 p.m. Patterson Hall 117 (University of Nebraska Lincoln)
David Pitts Title: Von Neumann Algebras and Extensions of Inverse Semigroups Abstract: linkOctober 21 - joint seminar with USD Math Club■ 4 p.m. - 5 p.m. Patterson Hall 117 (University of North Dakota) Cristina Oancea Title: From Functional Analysis to cancer epidemiology: the life path of a mathematician/statistician trying to save lives Abstract: linkNovember 10 4 p.m. - 5 p.m. Patterson Hall 117■ (USD) Jessie Byrnes Title: Bayesian Estimates via Markov Chain Monte Carlo
Algorithm Abstract: link Spring 2016 April 13 ■ 4 p.m. - 5 p.m. Room AS 103 (USD)
Ricardo Cervantes Title: Temporal Dynamics of various Predator and Prey
Models
Abstract: The study of how and why population numbers change in time and
space, or equivalently, population dynamics have puzzled humanity from
prehistoric times. As ecological systems are characterized by the interaction
between species and their surroundings, one of the fundamental goal is to be
able to understand how the interaction of individual organism with each other
and with the environment can influence population interaction and the
composition of communities over a wide range of temporal domains. An
important type of interaction which affects population dynamics of all species
is predation. One of the reasons why predation is important is that no organism
can live, grow, and reproduce without consuming resources. Temporal models
describing predator-prey models have been in the focus of ecological
science since the early days of this discipline and it continues to draw
interest from both applied mathematicians and ecologists as they exhibit a wide
range of interesting dynamical behaviors such as steady states, oscillations
and chaos. Fall 2015October 28■ 4 p.m. - 5 p.m. AS 107, (USD)
Jose Flores Title: Dynamics of a biological pest control model : How the
species interact?
Abstract: In this presentation we analyze a predator-prey model
to control a pest by introducing its natural predator. Spring 2015February 3■ 9 a.m. - 10 a.m. AS 105, (Iowa State)
Eric Weber Title: Spectral Theory of Small Hadamard MatricesAbstract: We
prove that if $A$ and $B$ are Hadamard matrices which
are both of size $4 \times 4$ or $5 \times 5$ and in dephased form, then
$tr(A) = tr(B)$ implies that $A$ and $B$ have the same
eigenvalues, including multiplicity. We
calculate explicitly the spectrum for these matrices. We also extend these results to larger
Hadamard matrices which are permutations of the Fourier matrix and calculate
their spectral multiplicities.
March 5■ 4 p.m. - 5 p.m. AS 106, (Dordt College)
Mike Janssen Title: Symbolic Powers of Ideals: Problems and ProgressAbstract: Symbolic powers of ideals have been the focus of much
recent study in commutative algebra and algebraic geometry. Problems in
algebraic geometry (e.g., Waring’s problem) and commutative algebra (e.g., the
question of containment in ordinary powers of ideals) have motivated much of
this work, but symbolic powers also have applications to other fields, such as
computer science, combinatorics, and graph theory. We will explore the
questions that have motivated the study of symbolic powers of ideals and share
recent results in this direction.
April 23■ 4 p.m. - 5 p.m. AS 106, Edoardo Persichetti (Dakota State) Title: Post-Quantum Cryptography Abstract: In
this talk I will present the latest development in the post-quantum
cryptography area. The talk will include mathematical content related to the
major areas of interest, such as multivariate equations, linear codes and
lattices, but will be aimed at a general audience. Everybody is welcome! FALL 2014October 16, 4:15 p.m. - 5:15 p.m., AS 105■ (Counseling & Psychology in Education, USD) Harry Freeman Title:
How strong is our love for one person?
Abstract: I am interested in comparing the level of support we
expect from our most significant relationship relative to others in our support
network. Under what conditions can we
make the claim that individuals value a single individual more than all others
in their support networks. Can a probability be computed for a non-parametric
distribution, or is it better to set an effect size based on the sample using inferential stats?
November 5, 4 p.m. - 5 p.m., AS 107■
Steven Nathan Harding (Mathematical Sciences, USD) Title: Generalized Walsh transforms, Cuntz algebras representations and
applications in signal processing
Abstract: Many applications
such as compression and data representation in the area of signal processing
are based on Hilbert spaces and their orthonormal bases. In this talk, we
explore old (classic) and new orthonormal bases in the Hilbert space L^{2}[0,1],
as well as some of their applications to signal processing. It is well-known
that the classic Walsh functions serve as an orthonormal basis for the L^{2}[0,1]
space; in a recent paper published by Dutkay, Picioroaga, and Song, the authors
developed a generalized form of this basis. In my talk I will discuss
convergence and continuity properties of the generalized Walsh series. I will
also show how unitary N x N matrices, along with the quadrature mirror filters
that implement them, give rise to representations of Cuntz isometries on L^{2}[0,1].
In this setting, a signal can be encoded or encrypted on N-channels according
to filters generated by the unitary matrix. Partial results will be presented
on the security of an encryption scheme that implements these Cuntz isometries.
Benton Duncan (Department of Mathematics, NDSU) Title: Algebras associated to continuous dynamics I will survey recent results concerning algebras (mostly
operator algebras) associated to dynamical systems. Mostly these algebras are of interest to
operator algebraists because they give a class of algebras which are
"understandable" and "interesting". I will talk about why they are understandable
and what makes them interesting.Abstract: SPRING 2014January 29, 4 p.m. - 5 p.m., AS 107■ Nathan Tintle (Dordt College) Title: The use of randomization methods in teaching introductory statisticsAbstract: A growing movement
in statistics education is to use permutation, bootstrapping and simulation methods
(broadly defined as ‘randomization methods’) when teaching introductory
statistics to non-math majors (Stat 101). I will provide a history of this
movement, with particular attention to a textbook under development by myself
and six others (Beth Chance, George Cobb, Allan Rossman, Soma Roy, Todd Swanson
and Jill VanderStoep; http://math.hope.edu/isi). I will compare and
contrast our approach with the traditional sequence of topics in Stat 101 and a
few other randomization-based curriculum projects underway, summarize published
assessment data on these approaches and discuss implementation details.
Marvin Gamble (USD) Title: Primitive Pythagorean Triples: From here to infinity? Abstract: Are there an
infinite number of primitive Pythagorean triples? Using number theory I will show the answer to
this question and how to find these triples.
I will prove what numbers can and cannot be used in the triples and
prove the method that will be demonstrated.
This should be an interest to all secondary math education majors and next semesters number theory students.
Catalin Georgescu
(USD)About
Existence of Solutions of Differential Equations
■
October,
24, AS, Room 107, 4 p.m. - 5 p.m.Ionut Chifan (University
of Iowa)Rigidity in von Neumann algebras
November,
7, AS, Room 107, 4 p.m. - 5 p.m.■ Gabriel Picioroaga (USD) Processing and encrypting images with Maple
■
March
28, AS, Room 105, 4 p.m. - 5 p.m.Ginger McKee (Wolfram
Research) Mathematica
in Education and Research
Abstract: This talk illustrates capabilities in Mathematica 8 that are directly applicable for use in teaching and research on campus. Topics of this technical talk include: * Free forum input * 2D and 3D visualization * Dynamic interactivity * On-demand scientific data * Example-driven course materials* Symbolic interface construction * Practical and theoretical applications. Whether or not you're familiar with Mathematica, you'll find this seminar worthwhile--so don't forget to pass the invitation on to your colleagues and students. All attendees will receive an electronic copy of the examples, which can be adapted to individual projects. September 21, AS, Room 107, 4 p.m. - 5 p.m.FALL 2011 ■ Rodica Curtu (Department of
Mathematics, University of Iowa)Selection of mixed-mode oscillations in a neuronal competition model Mixed-mode oscillations (MMOs) are temporal periodic activity
patterns characterized by notable changes in amplitude: during each cycle, there
is an alternation between small-amplitude oscillations and large, fast
excursions of relaxation type. MMOs arise in a variety of physical systems; in
particular, they were observed in in-vitro experiments at both individual neuron
and neuronal population levels and, more recently, they were also found in
computational neuroscience models. This talk will show the existence of MMOs in a neuronal competition model that
involves slow negative feedback and gain function nonlinearities, and depends on
a control parameter associated with external constant stimuli. Analytical and
numerical investigation of the system uncover an interesting, novel property of
the MMOs: they are periodic canards, but their small amplitude oscillations
result from a combined effect of the folded node funnel (canard-induced
rotations) and the spiraling unstable manifold of a nearby equilibrium (Hopf-induced
rotations). One distinctive feature of the model is that the MMOs are periodic
solutions that exhibit small amplitude oscillations and canard behavior twice
per cycle; this is due to the fact that transition between the dynamics on the
slow manifold and that along the fast fibers occurs near a folded node on both
lower and upper branches of the slow manifold. Abstract:
Akim Adekpedjou (Department of
Mathematics and Statistics, Missouri University of Science and technology)Recurrent Events: Modeling and Statistical Inference In various field such as reliability,
economics, sociology, biomedical studies, it is often of interest to monitor
occurrence of an event. Such event could be the failure of an electronic system,
outbreak of a disease, claim filing, etc…. These events recur and so it is of
interest to describe their recurrence behavior through a stochastic model. This
talk pertains to the modeling and statistical inference with recurrent event
data. I will first discuss some results in the single event setting and show how
that translate into recurrent events. I will then summarize some important
inference and asymptotic results pertaining to the estimation of the
distribution function of the gap-time in recurrent event models. These results
are based on important aspects of recurrent events that are not accounted for in
the current literature. The discussions on the estimation of the distribution
function of the gap-time will be followed by the development of chi-squared type
test for testing a simple parametric null model. I will next investigate small
sample and asymptotic properties of the test as well as power analysis against a
sequence of Pitman's alternatives. Application to some real datasets will be
demonstrated. Finally some open problems pertaining to recurrent events will be
indicated.
Abstract: Keywords: Recurrent events; Sum-quota constraint; Informative monitoring; Martingales; Gaussian process; Weak convergence; Pitman's alternatives; Goodness of fit.
■
November 10, AS, Room 107, 4 p.m. - 5 p.m. Dmitri S. Kilin (Department of
Chemistry, University of South Dakota)Computational modeling of physical and chemical properties of nanostructured
silicon surfaces for electronics and photovoltaics
1. D. S. Kilin and D. A. Micha, "Surface Photovoltage at Nanostructures on Si Surfaces: Ab Initio Results" J. Phys. Chem. 113, 3530 (2009). 2. D. S. Kilin
and D. A. Micha, "Electronic Relaxation at a Photoexcited Nanostructured
Si(111)Surface" December 1, AS, Room 107, 4 p.m. - 5 p.m.■ Catalin Georgescu (USD)Topological Entropy
Abstract:
In
a broad sense, a dynamical system is given by the action of a group upon a
topological space. How the structure (and topology) of the group influences the
dynamics of the action generated a large body of mathematical work.
Among the many tools used, topological entropy proved to be one of the
most important. Originated from the standard concept of entropy of a physical
system, topological entropy is notoriously difficult to compute and most of the
open problems related to entropy revolved around this issue and around its
dependence on the parameters of the system.
I will present the basic properties of entropy and its connections to
algebraic and measure entropy, some examples and a brief overview of the
relation that exists between entropy and Lyapunov exponents.
■
February 24, AS, Room 107, 4 p.m. - 5 p.m. Y.L. Lio (University of South Dakota)A Novel Estimation Approach for Mixture Transition Distribution Model in
High-Order Markov Chains (joint work with D.G.
Chen)
■
March 3, AS, Room 104B, 4 p.m. - 5 p.m. Gleb Haynatzki
(University of Nebraska Medical Center)The speaker will give a presentation of the graduate program available at UN Medical Center and discuss career opportunities in Biostatistics and Public Health (data management, pharmaceutical and clinical trials, data analysis, academia and government agencies). The UNMC College of Public Health Biostatistics Department collaborates with scientists, physicians, clinical investigators and other researchers, provides statistical consulting, teaches courses in biostatistics, and conducts methodological research. The Department's expertise includes clinical trials, study design, surviving analysis, general linear models, longitudinal analysis, survey methodology, and analysis of microarray gene-expression data and other high-dimensional data.
Valentin Matache (University of
Nebraska at Omaha)Function theory and composition operators on spaces of analytic functions
Composition operators
are operators acting on spaces of functions on a set S, byAbstract: composition
to the right with a fixed selfmap of S. They have been systematically
studied since the late sixties. However, composition operators were implicitly
present in the mathematical literature much earlier than that. The theory of
composition operators acting on holomorphic function spaces is by far the most
developed. In this talk, we will address some major directions of investigation,
emphasizing how the research on those topics mixes operator theory and function
theory in a harmonious way, and reporting on the speaker’s own contributions.■
March 26, AS, Room 107, 4 p.m. -
5 p.m. Il Woo Cho (St. Ambrose
University )Distorted Histories
Abstract: In this talk, we consider distortions
on histories. A Mathematical history is determined by a certain type I von
Neumann algebra "M" in a fixed operator algebra B(H), equipped with an
automorphism group, which is an one-parameter group satisfying some additional
conditions, called an E_0 group. By fixing a finite number of partial isometries
in B(H) with a suitable connection with each other, we can show the existence of
the distortion of M distorted by the partial isometries. Also, we can
characterize the von Neumann algebra distorted by partial isometries.
■
April 14, AS, Room 107, 4 p.m. -
5 p.m.Nan
Jiang (University of South Dakota) The Convergence of a
Class of Methods -
semi-discrete case
In the talk, we will introduce a
class of high resolution schemes, using flux limiters for hyperbolic conservation
laws. In the 80's, Sweby [SIAM
J. Numer. Anal. 21 (1984)]
constructed and predicted the entropy convergence of this family of schemes.
However, the convergence issues of these problems have been open. In the last
part of this talk, I will present my recent progress in the convergence analysis
of this class of schemes, which extends our previous convergence results [Jiang
and Yang, Methods
and Applications of Analysis,
Vol. 12, No. 1 (2005) pp. 089-102].
Remarkably, by showing the the convergence of the schemes with Roe's superbee
limiter, our convergence criteria [Yang and Jiang,
Methods and Applications of Analysis
Vol. 10 (2003), No. 4, 487-512] also
guarantee the entropy convergence of any flux limiter method. Thus, the entropy
convergence problems of the entire family of Sweby's flux limiter schemes can be
put to the rest. The talk is accessible to the senior math major and the
graduate students.Abstract: Key words and phrases. Conservation law with source terms, schemes with flux limiters, entropy convergence.
■
October 21, AS, Room 16B, 4 p.m. - 5 p.m. Clare Wagner (USD)SMART Board and SMART Notebook Basics Abstract: This
presentation will provide an introduction to how to use a SMART Board in a
mathematics classroom. Useful features of SMART Notebook software in preparing
lecture outlines prior to teaching in a mathematics classroom will also be
shared.
November 4, AS, Room 16B, 4 p.m. - 5 p.m.■ Jose Flores
(USD)
A Leslie-Gower predator-prey model with Allee effect on the preyIn this
paper we study a predator-prey model described by autonomous bi-dimensional
differential equations systems in which we considered the following three
properties: Abstract: (a) The equation for predator is a logistic function of the Leslie-Gower type, (b) the prey population is affected by the Allee effect, and (c) the functional response is linear function or a function of Holling type I. The interest of our work is in establishing the quantity of limit cycles of the system. The study of this type of mathematical model intends to understand the oscillatory behavior of many real world phenomena in nature. (*) This work is in collaboration with: Eduardo González-Olivares, Betsabe González-Yañez, Jaime Mena-Lorca and Alejandro Rojas-Palma at the Institute of Mathematics at the Pontificia Universidad Católica de Valparaíso, Valparaíso Chile ■
November 9, AS, Room 104B, 4 p.m. - 5 p.m. Keith Stroyan
(University of Iowa)Visual Depth Perception from Motion Parallax
■
November 18 , AS, Room 16B, 4 p.m. - 5 p.m.Y. L.
Lio (USD)The Implementation of R program for
Acceptance Sampling Plans from truncated Life Tests for Birnbaum-Saunders
DistributionTime to failure due to fatigue is
one of the common quality characteristics in material engineering applications.
The Birnbaum-Saunders distribution has been proved to provide a better fitting
for the fatigue data set than the Weibull distribution does.
In this talk, the comparison for two
sampling plans from truncated life tests for Birnbaum-Saunders distribution will
be implemented by R program. Abstract: ■
December 2 , AS, Room 16B, 4 p.m. - 5 p.m.Gabriel
Picioroaga (USD) C* Dynamical Systems
A classical dynamical system consists of a compact Hausdorff space X together
with a homeomorphism σ : X
→ X. The study of
the iterates σ◦σ…◦σ often leads to the existence of
an attractor A on which σ displays "chaotic"
behavior (e.g. Julia sets). There are other ways to generate attractors for
example by means of an iterated function system (IFS) where the IFS are
contractions: a theorem of Hutchinson provides the attractor. While appealing
from the point of view of (fractal) geometry (and quite esthetic) these
attractors are ill-behaved. Many a times one studies a space by means of the
real or complex (continuous or smooth) valued functions on it. It may seem like
that
for fractals such study would bring nothing to the table, due to their
"monstrous " geometry : every function could be
continuous and/or smoothness may make no sense. Abstract: In my talk I will give an introduction to C* dynamical systems and justify why it provides a comfortable setting to incorporate fractals into mainstream (Functional) Analysis. In this setting the "ill behavior" of the attractors will mean that "non-commutativity" is at play. In the particular case when A is a Cantor set I will talk about the quantum differential df=[F,f] where F is a Fredholm module over the algebra of real valued functions on A thought of as multiplication operators. |

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