UMD Department of Mathematics and Statistics

$Math and Stats$

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Phone: 218-726-8747 / 218-726-8254
Fax: 218-726-8399
Email: mathstat@d.umn.edu
Undergraduate Studies
Email: math.dus@d.umn.edu
Graduate Studies
Email: math.dgs@d.umn.edu
140 Solon Campus Center (map)
1117 University Drive
Duluth, MN 55812-3000

Home > Seminars and Colloquia

Seminar and Colloquia

Lecture The Department of Mathematics and Statistics offers a weekly colloquium series on Thursdays. Most colloquia begin between 3:00 and 3:30. Seminars alternate between those aimed at Undergraduate (type U) and Graduate (type G) audiences. Calendar of current events

Type	Date	Title	Speaker
G	5/5/11	New Mathematical Challenges from Bioinformatics	Marshall Hampton, UMD Department of Mathematics and Statistics
U	4/28/11	Listening to Students' Statistical Reasoning: The Case of Sampling Tasks	Mike Shaughnessy, National Council of Teachers of Mathematics
U	4/26/11	Mathematical Contest in Modeling 2011	James McKeown, Abhi Devireddy, Yue Wang, Yan Zhuang, Adam Flanagan, Yuantao Peng
U	4/21/11	Honors Colloquium - Group II	Brock Burgau, Phil Nelson, Collin McCaulley Van Ryn
U	4/20/11	Honors Colloquium - Group I	Linglu Liu, Yini Fu, Brian Christner
U	4/7/11	Between the Folds	Director Vanessa Gold
U/G	3/31/11	Model Validation and the Value-at-Risk Model	Lindsey Dietz, U.S. Bank
U	3/24/11	Retail Analytics at Target	Karl Kruppstadt, Target Corporation
G	3/10/11	Newton's method: how spectacular can failure be?	Bruce Peckham UMD Department of Mathematics & Statistics
G	3/3/11	Development of a Vegetation-Soil-Consumer Model with Harvesting	Tom Sjoberg MS Candidate: Program in Applied and Computational Mathematics
U	3/3/11	Measuring Risk under Adaptive Threats	Jonathan Drexler, MITRE-CAASD
G	2/24/11	Research Topics	Faculty of the UMD Department of Mathematics and Statistics
U	2/17/11	The Rasch Model: Measuring Ability and Difficulty	Steven Rosenberg, Associate Professor UWS,Department of Mathematics & Computer Science
G	2/10/11	On Minimum Edge-cuts in Graphs	Sergei Bezrukov, UWS
U	2/3/11	The 2009 International Mathematical Olympiad	Documentary
G	1/27/11	Standard Bayes, Empirical Bayes and Bayesian Foraging	Dick Green, UMD Department of Mathematics and Statistics
G	1/20/11	Modeling Count Data from Hawk Migrations	Fengying Miao MS Candidate: Program in Applied and Computational Mathematics
G	12/9/10	The Next Big Step as a Math Grad Student at UMD	Several second-year graduate students
G	11/23/10	Enrichment in a Producer-Consumer Model with varying rates of Stoichiometric Elimination	Xinyuan Zhang, MS Candidate: Program in Applied and Computational Mathematics
U	11/18/10	UMD's Undergraduate Research Opportunities Program: My Experience, the Benefits, and Getting Started	Amy Schmidt, Applied and Computational Mathematics Graduate Student
U	11/4/10	The 10,000-Hour Rule	Dick Green, UMD Department of Mathematics & Statistics
U	10/28/10	Voting Methods for Political Elections	Eric Erdmann, Applied and Computational Mathematics Graduate Student
G	10/22/10	Distance Magic Graphs - A Survey	S. Arumugam, National Centre for Advanced Research in Discrete Mathematics, Kalasalingam University, India
G	10/19/10	Recent Advances in the Degree/diameter Problem	Mirka Miller School of Electrical Engineering and Computer Science University of Newcastle, Australia
G	10/14/10	Some of my favorite problems about finite set systems: easy to state and understand, some solved, some not, and all interesting	Ian Roberts Charles Darwin University, Autstralia
U	10/7/10	The Role of Statistics and Programming in Medical Research	Matthew Plevak and David Hodge Mayo Clinic
G	9/30/10	Stability of an Interconnected System of Euler-Bernoulli Beam and Heat Equation with Boundary Coupling	Jun-Min Wang Department of Mathematics, Beijing Institute of Technology, China
U	9/16/10	Employment at Securian Financial Group	Natasha Farooq, Leah Tollefson, and Brian Christner

Employment at Securian Financial Group
by

Natasha Farooq, Leah Tollefson, and Brian Christner

Abstract:
This colloquium will include three parts: A synopsis of Securian Financial Group and their internship program by Natasha Farooq, a personal account of Securian’s internship program in actuarial science by Brian Christner and a discussion of the day-to-day activities of an actuary at Securian by Leah Tollefson. Questions to be answered: What does an actuary do? How do I become an actuary? How should I begin applying for internships and jobs in the actuarial sciences? What does Securian do?

Time: Thursday, September 16, 3:00PM -- 4:00PM
Location: 150 Chemistry

Stability of an Interconnected System
of Euler-Bernoulli Beam and Heat Equation with Boundary Coupling
by

Jun-Min Wang
Department of Mathematics,
Beijing Institute of Technology, China

Abstract:
In this talk, we present the stability of an interconnected system of Euler-Bernoulli beam and heat equation with boundary coupling, where the boundary temperature of the heat equation is fed as the boundary moment of the Euler-Bernoulli beam and, in turn, the boundary angular velocity of the Euler-Bernoulli beam is fed into the boundary heat flux of the heat equation. We conclude that the spectrum of the closed-loop system consists only of two branches: one along the real axis and the other along two parabolas symmetric about the real axis and open to the imaginary axis. The asymptotic expressions of both eigenvalues and eigenfunctions are obtained. With a careful estimate for the resolvent operator, the completeness of the root subspaces of the system is verified. The Riesz basis property and exponential stability of the system are then proved. Finally we obtain that the semigroup, generated by the system operator, is of Gevrey class \delta>2.

Time: Thursday, September 30, 3:00PM -- 4:00PM
Location: 130 Solon Campus Center

The Role of Statistics and Programming in Medical Research
by

Matthew Plevak and David Hodge

Mayo Clinic

Abstract:
The vision of research at Mayo Clinic is to improve human health and enhance the understanding of human disease through excellence in the field of Biomedical Statistics and Informatics. This vision becomes a reality when experts in database management, programming, and statistics team up with medical clinicians to explore the pressing medical questions of the day. In this presentation we will describe the various roles of the statistical team, detail the required background and training, give an example of this collaborative effort, and provide information on how to apply for jobs at the Mayo Clinic. Matt Plevak is a UMD alumnus.

Time: Thursday, October 7, 3:00PM -- 4:00PM
Location: 150 Chemistry

Some of my favorite problems about
finite set systems: easy to state and understand,
some solved, some not, and all interesting

Ian Roberts

Charles Darwin University, Australia

Abstract:
Sets are the most basic object in mathematics, and their theory mimics many of our basic ways of organizing information. Despite the intensive use and study of sets for more than 100 years, there are still many simple to state problems on finite sets which have not previously been asked, which are not answered, or which are not answered with an elegant proof. A range of such problems will be considered, and in every case the questions could be considered to be accessible to high school students, but more sophistication may be needed to make progress on the solutions. The problems could provide a good source of interesting and accessible work for graduate students. Definitions and questions will be provided, with time allowed to work on them to gain an immediate understanding. In the process some of the more important but accessible theorems will be introduced. There's a money back guarantee if you can't follow the talk – the notion of a subset is the most important idea!

Time: Thursday, October 14, 3:00PM -- 4:00PM
Location: 130 Solon Campus Center

Recent Advances in the Degree/diameter Problem

Mirka Miller
School of Electrical Engineering and Computer Science, University of Newcastle, Australia

Abstract:
A well-known fundamental problem in extremal graph theory is the degree/diameter problem, which is to determine the largest possible order of graphs or digraphs or mixed graphs of given maximum degree, respectively, maximum out-degree, respectively, mixed degree; and given diameter. This is an open problem for most values of degree and diameter. Lower bounds of the largest orders are obtained by constructions. General upper bounds, called Moore bounds, exist for the largest possible order of such graphs, digraphs and mixed graphs of given maximum degree d (respectively, maximum out-degree d, resp., maximum mixed degree d) and diameter k.

In recent years, there have been many interesting new results in all the three versions of the degree/diameter problem, resulting in improvements in both the lower bounds and the upper bounds on the largest possible number of vertices. In this talk we present an overview of the current state of the degree/diameter problem, for undirected, directed and mixed graphs, and we outline several related open problems.

Time: Tuesday, October 19, 3:00PM -- 4:00PM
Location: 130 Solon Campus Center

Distance Magic Graphs - A Survey

S. Arumugam, National Centre for Advanced Research in Discrete Mathematics,
Kalasalingam University, India

Abstract:

Let G = (V, E) be a graph of order n. A bijection f : V → {1, 2, . . . , n} is called a distance magic labeling of G if there exists a positive integer k such that Σ f (u) = k for all v ∈ V, where N (v) is
	μ ∈ N (v)
the open neighborhood of v. The constant k is called the magic constant of the labeling f. Any graph which admits a distance magic labeling is called a distance magic graph. In this paper we present a survey of existing results on distance magic graphs along with our recent results, open problems and conjectures.

Time: Thursday, October 22, 3:10 PM
Location: Library Rotunda

Voting Methods for Political Elections

Eric Erdmann

Applied and Computational Mathematics graduate student

Abstract:
Elections, such as the one next week, are essential to our democracy. As demonstrated in the rancorous and costly 2008 United States senate election in Minnesota, our plurality method of electing officials has serious drawbacks. Arrow’s Theorem states, in precise terms, how no ranked-order voting method is perfect. We will review Arrow’s Theorem and how various voting methods fail to meet desirable criteria. Shortcomings of plurality, instant runoff and Borda count voting methods will be reviewed. Instant runoff voting has been used as an alternative for political elections, and historical experiences with it, some counter-intuitive, will be discussed. Another method, the Borda count, has also been used in practice and will be discussed. Range voting will be presented as an alternative to ranked-order voting methods. Finally, we will note how no voting method can compensate for the serious problems of voter apathy and ignorance.

Time: Thursday, October 28, 3:00PM -- 4:00PM
Location: 150 Chemistry

The 10,000-Hour Rule

Dick Green

UMD Department of Mathematics & Statistics

Abstract:
According to a rule suggested by psychologist Anders Ericsson: It takes about 10,000 hours of deliberate practice to become an expert in many fields, including music, sports and games. This idea was popularized in the book, "Outliers: The Story of Success," by Malcolm Gladwell. More recently, Matthew Syed, an English table tennis champion, wrote a book, "Bounce: How Champions are Made," which shows how the 10,000 hour applies to sports. In this talk I will discuss the 10,000-hour rule and a related idea - relative age. I will talk about the ideas and their inventors, and I will give a number of examples. I will also talk about some early figures in the nature-nurture debate, including Francis Galton and James McKeen Cattell. Finally, I will ask what is the relevance of the study of expertise in expert performers to the education of ordinary, and extraordinary, citizens.

Time: Thursday, November 4, 3:00PM -- 4:00PM
Location: 150 Chemistry

UMD's Undergraduate Research Opportunities Program:
My Experience, the Benefits, and Getting Started

Amy Schmidt

Applied and Computational Mathematics graduate student

Abstract:
As a UMD graduate, I share my experience in the Undergraduate Research Opportunities Program: why I chose to participate, how I got started, and how it enhanced my education. The benefits and motivations of undergraduate research are discussed, focusing on how to begin the research process and the personal growth and valuable experiences gained from it. Also addressed are the opportunities for, and given by, undergraduate research.

Time: Thursday, November 18, 3:00PM -- 4:00PM
Location: 150 Chemistry

Enrichment in a Producer-Consumer Model with varying rates
of Stoichiometric Elimination

Xinyuan Zhang
MS Candidate: Program in Applied and Computational Mathematics

Abstract:
Producer-consumer (predator-prey) systems have been studied for many years. Stoichiometry has recently been included in models to track food quality as well as quantity. Laura Zimmermann developed a stoichiometric elimination model with differential equations in 2006, keeping track of food quantity through carbon and food quality through a nutrient. Whichever is present in excess is eliminated. We extend her analysis by investigating more closely at the stoichiometry of the producer and consumer. We also look at the effects of increasing the elimination rates; in the limit, the system can be reduced to a lower-dimensional one. By varying parameters representing the enrichment of carbon and/or nutrient, we see interesting sequences of bifurcations, including transitions from monoculture to coexistence, coexistence equilibrium states to coexistence periodic states, and a transition to bistable behavior.

Time: Tuesday, November 23, 10 AM
Location: 130 Solon Campus Center

The Next Big Step as a Math Grad Student at UMD

Abstract:
By the end of your first semester of the Applied and Computational Mathematics program, you will probably have found your stride as a teaching assistant or graduate student in the classroom. The next, and biggest step is your second semester. You will have to choose a research topic and adviser, apply for the department's Summer Research Fellowship, complete the Application for Comprehensive Examination and the Degree Transmittal forms, and finish the semester with the Comprehensive Exam. This can be a confusing process, so we suggest how to complete each task successfully and include a list of important deadlines. Several second year students will share their experiences and be available for questions.

Time: Thursday, December 9, 3 PM
Location: 130 Solon Campus Center

Modeling Count Data from Hawk Migrations

Fengying Miao
MS Candidate: Program in Applied and Computational Mathematics

Abstract:
A statistical model is used to predict the probabilistic future behavior of a system from data. In order to get best estimates of response variable for a particular system, it is important to fit proper model for best describing data. The traditional methods of transforming data to satisfy the assumptions of general linear model might work well for continuous variable and certain discrete variable. However, these methods might not perform well for discrete variable with ‘zero’ observations. In my research, investigations have been done into finding appropriate models to analyze count data such as hawk migration counts. Model selection from LM regression, GLMs and NLMIXED is based on simulations that will be done separately for simulating Poisson data and log-normal data. The GLMs are used by specifying Poisson and negative binomial distributions. A mixed model fit with SAS proc MIXED is used for the real hawk data to account for dependence of observations on the same day and from the same site.

Time: Thursday, January 20, 10 AM
Location: 130 Solon Campus Center

Standard Bayes, Empirical Bayes
and Bayesian Foraging

Dick Green
UMD Department of Mathematics and Statistics

Abstract:
In his stochastic model for foraging in a patchy environment, Oaten [Theoretical Population Biology 12:263-285 (1977)] used a standard Bayesian approach. He assumed that predators know the distribution of the numbers of prey in patches. Most theoretical work, including early work by Yoh Iwasa and his colleagues, by John McNamara, and by myself, and more recent work by Ola Olsson and his colleagues, has followed Oaten’s lead and used a standard Bayesian approach.

In real life, however, the quality of the environment may change over time and a foraging animal should change its foraging strategy. A method that statisticians use to deal with problems such as environmental change is called empirical Bayesian inference. In this method, an estimate of overall environmental quality is made, and this estimate is used to help estimate the quality of each patch.

In this talk, I will begin by describing standard Bayesian inference. Then I will show how standard Bayesian inference is used to find the optimal foraging strategy in Oaten’s model. Finally, I will sketch the idea of empirical Bayesian inference and show how parametric empirical Bayes may be used to determine good foraging strategies for use in a changing, patchy environment.

Time: Thursday, January 27, 3 PM
Location: 130 Solon Campus Center

The 2009 International Mathematical Olympiad

Documentary

Abstract:
The 50th International Mathematical Olympiad (IMO) was held in Germany in 2009. The IMO is a contest for the world's most talented high school math students. More than 100 countries send their best six students to compete in the two-day event. This colloquium is a documentary DVD about the contest. Two members of the U.S. IMO team participated in the 2010 UMD summer undergraduate research program in math. One of them finished second in 2009 IMO competition.

Time: Thursday, February 3, 3 PM
Location: 150 Chemistry

On Minimum Edge-cuts in Graphs

Sergei Bezrukov, UWS

Abstract:
Some basic results on minimum edge-cuts in graphs will be presented along with their short proofs. We will also present some more recent results for various graph families.

Time: Thursday, February 10, 3 PM
Location: 130 Solon Campus Center

The Rasch Model: Measuring Ability and Difficulty
by

Steven Rosenberg
Associate Professor
University of Wisconsin-Superior
Department of Mathematics & Computer Science

Abstract:
Developed by mathematician-turned-consultant Georg Rasch in themid-twentieth century, the Rasch Model claims to provide measurements for both the absolute ability of each student and the absolute difficulty of each question on an exam. A combination of undergraduate-level statistics and calculus are all that is required to understand the math behind the Rasch Model. We will present the model, sketch proofs of the existence and uniqueness of solutions to the maximum-likelihood estimates of the model parameters, and finally draw a connection with discrete mathematics by bringing in "split graphs."

Time: Thursday, February 17, 3 PM
Location: 150 Chemistry

Research Topics
by

Faculty of the
UMD Department of Mathematics and Statistics

Abstract:
Members of the UMD Department of Mathematics and Statistics will present some of the many interesting aspects of their research. Get a better understanding of faculty members' research interests and perhaps find a topic that could become the basis for your thesis/project research.

Time: Thursday, February 24, 3 PM
Location: 130 Solon Campus Center

Development of a Vegetation-Soil-Consumer Model with Harvesting

Tom Sjoberg
MS Candidate: Program in Applied and Computational Mathematics
Advisor: Dr. Harlan Stech

Abstract:
Through the derivation, parameterization, and simulation of a differential equation model, we analyze the relational impacts in the vegetation-soil-consumer ecosystem. There are numerous parameters that affect this ecosystem. However, we focus on the impact of harvesting the vegetation, or harvesting the consumer, or the introduction of fertilization to the soil to determine the impact that these activities have on the stability of the ecosystem. We find that there are parameter values that allow the system to be at a favorable stable equilibrium, and there are parameter values that create an unstable ecosystem, or cause the system to crash to an unfavorable state.

Time: Thursday, March 3, 9 AM
Location: 130 Solon Campus Center

Measuring Risk under Adaptive Threats

Jonathan Drexler, MITRE-CAASD

Abstract:
In 2003 former Department of Homeland Security Secretary Tom Ridge testified before the Senate Subcommittee on Commerce, Science and Transportation that improving security requires finding the balance point between the "costs of security" and the "costs of insecurity." This is a difficult task as the threats are directed by an opponent and can be adapted as security methods change.

The purpose of this talk is to provide insights on how to measure risk under adaptive threats. Static and adaptive threats will be defined and applied to the concepts of safety and security systems. Risk will then be introduced via commonly used nomenclature of threat, vulnerability and consequence. Calculating risk in a static environment will be presented using this nomenclature. To transition from calculating risk under static threats to calculating risk under adaptive threats, non-mathematical visualizations will be used. The talk will conclude with a method for calculating risk under adaptive threats as well as some thoughts on model construction.

This talk is suitable for undergraduate and graduate students.
Jonathan is a UMD graduate.

Time: Thursday, March 3, 3 PM
Location: 150 Chemistry

Newton's method:
how spectacular can failure be?

Bruce Peckham
UMD Department of Mathematics & Statistics

Abstract:
Newton's method is one of the simplest and most effective numerical methods for approximating zeroes of a function. It works well because an initial guess near a zero quickly converges to that zero. If, however, the initial guess is not close to a zero, the method can fail to converge to any zero. This leads to some very interesting dynamics, with some beautiful accompanying pictures. This talk will focus on Newton's method for cubics. It will include results of work by former student Karl Kruppstadt and current student Brett Bozyk.

Time: Thursday, March 10, 3 PM
Location: 130 Solon Campus Center

Retail Analytics at Target

Karl Kruppstadt
Target Corporation

Abstract:
The data collected by retailers in today's world is astonishing. This presentation provides an overview of the data that is collected by Target and how it is used to make informed decisions. The retail analytics range from basic reporting to predictive modeling and optimization. Some specific examples of predicting the effectiveness of store expansion (multiple linear regression), optimizing staffing in a new format (linear regression and break-even analysis), effective couponing and marketing (basket analysis and association), and optimizing store and shelf layout (linear programming) are possible topics. The presentation will also address what skills are desired in the retail analytics world and what courses at UMD were especially applicable to his current role.

The presentation will be appropriate for undergraduates and graduate students.

Karl has a bachelor's degree in math and a master's degree in math from UMD
and was an instructor at UMD for several years.

Time: Thursday, March 24, 3 PM
Location: 150 Chemistry

Model Validation and the Value-at-Risk Model

Lindsey Dietz
U.S. Bank

Abstract:
Model validation is extremely important in the financial industry. Quantitative models are heavily relied on, therefore, it is incredibly important that they are being used correctly and providing reasonable results. One of these important models is Value-at-Risk (VaR). In this talk, model validation at U.S. Bank will be explained as well as a discussion on the three most well known VaR methodologies.

The presentation will be appropriate for undergraduates and graduate students.

Lindsey Dietz has a bachelor's and a master's degree from UMD.

Time: Thursday, March 31, 3 PM
Location: 150 Chemistry

Between the Folds

Director

Vanessa Gould

Abstract:
GREEN FUSE FILMS' award-winning documentary Between the Folds chronicles the stories of ten fine artists and intrepid theoretical scientists who have abandoned careers and scoffed at hard-earned graduate degrees--all to forge unconventional lives as modern-day paperfolders.

As they converge on the unlikely medium of origami, these artists and scientists reinterpret the world in paper, and bring forth a bold mix of sensibilities towards art, expressiveness, creativity and meaning. And, together these offbeat and provocative minds demonstrate the innumerable ways that art and science come to bear as we struggle to understand and honor the world around us--as artists, scientists, creators, collaborators, preservers, and simply curious beings.

"Luminously photographed", with a "haunting" original score featuring the Budapest Symphony Orchestra, the film paints an arresting portrait of the mysterious creative threads that bind us all-fusing science and sculpture, form and function, ancient and new.

Time: Thursday, April 7, 3 PM
Location: 150 Chemistry

Honors Colloquium

Group I
Linglu Liu: Mathematical Modeling of H1N1 Flu Pandemic
Yini Fu: Three methods of analyzing binomial data
Brian Christner: Statistical Arbitrage of Pairs Trading

Graduating with Honors from the Department of Mathematics and Statistics requires that students perform a research project with a department faculty member. This year's honors projects will be presented in the following two colloquia.

Time: Wednesday, April 20, 4 PM
Location: 130 Solon Campus Center

Honors Colloquium

Group II

Brock Burgau: Water Treatment and Pollution in Lake Superior
Phil Nelson: 3d Polyhedra Unfoldings in Sage
Collin McCaulley Van Ryn: A Look at World Population Growth Models

Time: Thursday, April 21, 3 PM
Location: 150 Chemistry

Mathematical Contest in Modeling 2011

First Presentation: James McKeown, Abhi Devireddy, Yue Wang

Second Presentation: Yan Zhuang, Adam Flanagan, Yuantao Peng

UMD Undergraduate Students
Department of Mathematics & Statistics

Each February, a nationwide Mathematical Contest in Modeling (MCM) for undergraduates is held. Contestants have 96 hours to select from one of two problems and submit a solution. This year three teams represented UMD. All chose the problem of designing the "shape" of a half-pipe to maximize "big air." Two of the teams will discuss the contest problem, their proposed solutions, and their overall experience with the competition.

Time: Tuesday, April 26, 2 PM
Location: 130 Solon Campus Center

Listening to Students' Statistical Reasoning:
The Case of Sampling Tasks

Mike Shaughnessy
National Council of Teachers of Mathematics

Mike Shaughnessy is currently serving as the President of the National Council of Teachers of Mathematics. Throughout his career, his research has focused on the teaching and learning of statistics and probability and the teaching and learning of geometry. From 2004-2008, Mike directed a four-year NSF ROLE (Research on Learning andEducation) project to investigate middle and secondary students' conceptions of variability and distribution in statistics.

Time: Thursday, April 28, 3 PM
Location: 150 Chemistry

New Mathematical Challenges from Bioinformatics

Marshall Hampton
UMD Department of Mathematics and Statistics

Abstract:
Sequencing 1,000,000 bases of DNA used to cost at least $5,000 back in 2001. Until 2008, the price dropped steadily until it was about $400 per megabase. Since then, astonishing improvements in sequencing have brought the cost to about 10 cents/megabase. This has begun a flood of data that requires new algorithms and gives rise to many new computational, statistical, and scientific challenges. This talk will survey some of these challenges, with an emphasis on a next-generation transcriptome project I am working on in collaboration with the lab of Dr. Matthew Andrews in the Department of Biology.

Time: Thursday, May 5, 3 PM
Location: 130 Solon Campus Center