# Seminar and Colloquia: 2007 - 2008

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.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.

- Archived 2012-13 Colloquia
- Archived 2011-12 Colloquia
- Archived 2010-11 Colloquia
- Archived 2009-10 Colloquia
- Archived 2008-9 Colloquia
- Archived 2007-8 Colloquia
- Archived 2006-7 Colloquia
- Archived 2005-6 Colloquia

Type | Date | Title | Speaker |

G | 7/5/08 | Wavelet-based Bootstrap and Its Application to Option Pricing | Junyan Shen, MS Candidate, Department of Mathematics UMD |

G | 7/3/08 | Design and Analysis of RT-PCR Measurements for RNA Expression | Feng Qian, MS Candidate, Department of Mathematics UMD |

G | 6/24/08 | What Makes a Champion? What Makes a Champion? A Multivariate Analysis of Major League Baseball | Lindsey Dietz, MS Candidate, Department of Mathematics UMD |

G | 6/12/08 | A STOICHIOMETRIC MODEL OF TWO PRODUCERS AND ONE CONSUMER | Laurence H. Lin, MS Candidate: Program in Applied and Computational Mathematics, Advisors: Bruce Peckham, Harlan Stech, John Pastor, Department of Mathematics and Statistics, UMD |

G | 6/5/08 | PERIODIC SOLUTIONS TO DIFFERENCE EQUATIONS | Katherine Niedzielski, MS Candidate: Program in Applied and Computational Mathematics, Advisors: John Greene, Department of Mathematics and Statistics, UMD |

G | 6/4/08 | VERIFYING AND DISCOVERING BBP-TYPE FORMULAS | Melissa Larson, MS Candidate: Program in Applied and Computational Mathematics, Advisors: John Greene, Department of Mathematics and Statistics, UMD |

G | 5/28/08 | Support Vector Machines | Brad Jannsen, MS Candidate, Department of Mathematics UMD |

G | 5/13/08 | Dynamic Efficiency for a Nonrenewable Resource Market with Variable Demand | Riitta Schaublin, MS Candidate, Department of Mathematics UMD |

U | 5/8/08 | Polish System of Education | Sylwia Cichacz, AGH University of Science and Technology, Crocow, Poland |

U | 5/6/08 | The Math Behind Some Computerized Puzzles | John Kiltinen, Professor Emeritus, Northern Michigan University |

U | 5/2/08 | Honors Colloquium | Laura Hoffman, Kathleen Malevich, Matthew Steffan, Garret Taft, Shawn Walwick |

G | 5/1/08 | Stefan Banach and "The Scottish Book" | Sylwia Cichacz, AGH University of Science and Technology, Crocow, Poland |

U | 4/24/08 | Mathematics and Law Enforcement | Sergeant Nicholas Alexander, Patrol Sergeant/Computer Forensics, Superior Police Department |

U | 4/17/08 | The Truth of Natural Numbers | Professor Yixin Zhu, School of Mathematical Science, Capital Normal University, Beijing, China |

U | 4/10/08 | Basic Image Compression with Wavelets | Professor Patrick VanFleet, Department of Mathematics, University of St. Thomas, St. Paul |

G | 4/3/08 | How Much Does it Cost a Parasitoid to be Unmated? | Professor Richard Green, Department of Mathematics, UMD |

U | 3/27/08 | Using Mathematica's Demonstration Project in the Calculus Classroom | Instructors Angela Sharp and Chad Pierson, Department of Mathematics, UMD |

G | 3/13/08 | The Hibernating Heart: mathematical tools for some unsolved problems | Professor Marshall Hampton, Department of Mathematics, UMD |

U | 3/06/08 | Native Americans in Mathematics: a Proud Past, and a Look to the Future | Professor Robert E. Megginson, Department of Mathematics, University of Michigan, Ann Arbor |

U | 2/28/08 | Broken Symmetries | Professor Robert L. McFarland, Department of Mathematics, UMD |

U | 2/21/08 | The Great Pi/e Debate (film) | Department of Mathematics, UMD |

U | 2/7/08 | Mathematics by Engagement | Angela Sharp, Department of Mathematics, UMD |

U | 1/31/08 | Hard Problems: The Road to the World's Toughest Math Contest ( Documentary Film ) | Department of Mathematics, UMD |

G | 12/21/07 | Comparison of Least Squares Method and Empirical Likelihood Ratio Method in Bifurcating Models | Wenjie Xu, MS Candidate Department of Mathematics UMD |

U | 12/14/07 | Pear Tree; No Partridge (or why math has come late to biology) | Professor Jay A. Johnson, University of Washington |

G | 12/11/07 | Hamiltonian Circuits in the Direct Product of Two Cyclic Groups | Rosa M. LeJeunesse, MS Candidate Department of Mathematics UMD |

U | 12/6/07 | Actuarial Internship Presentation and Panel Discussion | Matt Steffen, Brian Rock, Bridget Huss, UMD Students |

G | 11/30/07 | A 3-Dimensional Transient Kinetic-Diffusion Model of Nerve Regeneration | Professor Gregory Rutkowksi, Department of Chemical Engineering UMD |

U | 11/15/07 | Careers in Actuarial Science | Alex Kranz, UMD 2006 & Wesley Griffiths, UMD 2000 |

U | 11/12/07 | A Model Teacher-Scholar Program in Mathematics | Professor David Barker and Professor Saad I. El-Zanati, Department of Mathematics Illinois State University |

G | 11/08/07 | Modeling and Simulation: Systemic Approach | Professor Seraphin Abou, Department of Mechanical and Industrial Engineering |

U | 11/01/07 | The Poincare Conjecture | Jerimi Walker, Department of Mathematics and Statistics UMD |

U | 10/18/07 | Motivating Students with a Math Fair | Laura Zimmerman, Department of Mathematics and Statistics UMD |

G | 10/11/07 | Chaos in the Plane: Homoclinic Tangles and Loops | Professor Bruce Peckham, Department of Mathematics and Statistics UMD |

U | 10/04/07 | The Role of Statistics and Programming in Medical Research | Sara Fett and Paul Decker (UMD Graduate), Mayo Foundation |

U | 9/13/07 | Opportunitites for Undergraduate Research in Math and Statistics | Department of Mathematics and Statistics UMD |

G | 8/27/07 | Visualization of Vibration for a Space Truss Structure | Andrew Larson, Department of Mathematics and Statistics UMD |

G | 8/23/07 | Analysis of Sage Data Under Poisson Mixture Model | Xiaowei Zhan, Department of Mathematics and Statistics UMD |

G | 8/22/07 | A Study of the Dynamical Behavior of a Class of Advertising Models | Nicaise Mbunteu, Department of Mathematics and Statistics UMD |

**A Study of the Dynamical Behavior of a Class of Advertising Models**

Nicaise Mbunteu

Graduate Student

UMD Department of Mathematics and Statistics

**Abstract:**

In order to draw public attention to a brand of product that companies wish to sell, they use various types of notices and announcements. Assuming that the social dynamics of advertising is largely analogous to mathematic epidemiology, modeling can describe how individuals who are in a market for a brand of product can move from one purchasing class to another. In order to distinguish the different stages of the buying process to the advertising model, we segment the total population into classes of individuals: 1) the class of people who are unaware of the product; 2) the class of people who are aware of the product but not buying the product; and 3) the class of purchasers or consumers of the product. The goal is to build a model that explains the influence that advertising has on the success or failure of a product. Models with more than three subgroups are also considered.

**Time:**Wednesday, August 22, 2007 1:00 p.m - 2:00 p.m.

**Location:**130 Solon Campus Center

**Analysis of Sage Data Under Poisson Mixture Model**

Xiaowei Zhan

Graduate Student

UMD Department of Mathematics and Statistics

**Abstract:**

While Serial Analysis of Gene Expression (SAGE) technique is well developed and widely used, its data lacks meaningful explanation, such as finding similar functional tags. Comparing many clustering methods that are invented to solve this problem, recent papers, including cai et al., suggest a more applicable and reliable clustering method using a Poisson approach. Based on their work, the author proposed a new clustering method in which we not only associate every SAGE tag to a certain group but also calculate the probability of that association. We called it a Poisson Mixture Model. The number of clusters is determined using gap statistics. All these methods have been implemented by computer and their source code is available in the appendix.

**Time:**Thursday, August 23, 2007 3:00 p.m - 4:00 p.m.

**Location:**130 Solon Campus Center

**Visualization of Vibration for a Space Truss Structure**

Andrew Larson

Graduate Student

UMD Department of Mathematics and Statistics

**Abstract:**

Truss Structures are common in Earth-borne constructions, such as bridges and cranes, as well as in space applications. In recent years there has been renewed interest in inflatable-rigidizable space structures because of the efficiency they offer in packaging during boost-to-orbit. However, research is needed to better understand dynamic response characteristics, including inherent damping, of truss structures fabricated with these advanced material systems. A mathematical model of a joint-in-legs-beams system, a basic element of the truss structure has been obtained by Professor Zhuangyi Liu and his colleagues at Virginia Tech. Moreover, numerical solution of the system has been obtained by implementing a finite dimensional approximation scheme and computer programming. The focus of this paper is the presentation of the means used in visualizing the vibration of the structure and approximation to render the numerical data into a conceivable format.

**Time:**Monday, August 27, 2007 12:00 p.m - 1:00 p.m.

**Location:**130 Solon Campus Center

**Opportunities for Undergraduate Research in Math and Statistics**

UMD Department of Mathematics and Statistics

**Abstract:**

It comes as a surprise to some people that mathematicians and statisticians are still working to discover new mathematics! While some advances require years of background preparation in order to make any progress, others can be attacked with just an undergraduate background. In this colloquium, Professors Zhuangyi Liu, Dalibor Froncek and Marshall Hampton will describe a variety of potential research projects for undergraduates. The colloquium should be of interest to all Math/Stat students, whether or not you plan on doing a research project.

The talks will be preceeded by general information about this year's Undergraduate Colloquium Series (Professor Gallian), Math Club (Katie Malevich), Actuarial Club (Matt Steffen), and undergraduate research funding (Professor Peckham.)

EVERYONE IS WELCOME!

A pizza party hosted by the Math Club will follow from 4:30 p.m. - 5:30 p.m. New Math/Stat majors are especially invited to attend. Friends are welcome.

**Time:**Thursday, September 13, 2007 3:30 p.m - 4:30 p.m.

**Location:**130 Solon Campus Center

**The Role of Statistics and Programming in Medical Research**

Sara Fett and Paul Decker (UMD Graduate)

Mayo Foundation

**Abstract:**

Programming, data management and statistical analyses are used to assist our medical colleagues in answering a variety of research questions. The goal of our presentation is to give a broad overview of the different types of medical research questions and how programming, data management and statistical analyses are used to answer these questions. We will also share information on our application process and what we look for in prospective candidates at each level (B.S. and M.S.).

Note: while at UMD, Sara would like to interview UMD math and stat students between 11:00 A.M. and 2:30 P.M. who will grduate in December or May (B.S. or M.S.) and are interested in possible employment at the Mayo Foundation. Sara is interested in the technical background (statistical and computational) of applicants along with their attitude, initiative, and time management skills. Students interested in interviewing should bring a resume. Please contact Carol Stockman (cstockma) to schedule an interview.

**Time:**Thursday, October 4, 2007 3:00 p.m - 4:00 p.m.

**Location:**130 Solon Campus Center

**Chaos in the Plane: Homoclinic Tangles and Loops**

Professor Bruce Peckham

UMD Department of Mathematics and Statistics

**Abstract:**

A famous example of a map of the plane is the Henon map: f(x,y) = (y + 1 - ax 2, bx). Maps generate dynamical systems by using the map as a recurrence relation:(x{n+1}, y{n+1}) = f(xn, yn). An initial condition (x0, y0), along with a recurrence relation, generates and orbit (x0, y0), (x1, y1,), (x2, y2), ... . The basic goal in dynamical systems is to describe the long term behavior of orbits, how they depend on the initial condition, and how they depend the iteration function. The Henon map is famous because, at least for specific parameter values, the map has a Òchaotic attractor.Ó The chaos is due to the intersection of two special curves called the stable and unstable manifolds, respectively, in what is called a homoclinic tangle. In another example - a noninvertible one - chaos is created in a different way, through the creation of "loops" on an "invariant" curve.This talk will be an introduction to maps of the plane, bifurcations of invertible maps, and bifurcations of noninvertible maps.

**Time:**Thursday, October 11, 2007 3:00 p.m - 4:00 p.m.

**Location:**130 Solon Campus Center

**Motivating Students with a Math Fair**

Instructor Laura Zimmerman

UMD Department of Mathematics and Statistics

**Abstract:**

When students think of math, some may be excited and enjoy math, but many students have negative feelings toward the subject. Some say it is just too hard, they don't get it, or they have performed poorly in class in the past and have just given up. How can we get these students to feel better about math and their math skills? In this talk, I will discuss how to motivate students with a SNAP (Student-centered, Non-competitive, All-inclusive, and Problem-based) Math Fair. I will discuss how to set a class schedule, choose problems, make the displays, and design evaluation procedures. In addition, I will show some projects done by my students and discuss their reactions to the math fair as well as the benefits I noticed for the students.

**Time:**Thursday, October 18, 2007 3:00 p.m - 4:00 p.m.

**Location:**130 Solon Campus Center

**The Poincare Conjecture**

Jerimi Walker

UMD Department of Mathematics and Statistics

**Abstract:**

One of the oldest and most simply stated problems in topology is the Poincare Conjecture. While most people can understand the basic ideas behind the conjecture, the proof eluded mathematicians for over a century. When a proof released by Grigori Perelman in 2002 was finally verified in 2006, it was called the "Breakthrough of the Year" by Science magazine and created a firestorm of publicity and controversy. This was further fueled when Perelman was awarded, but declined to accept the Fields Medal, the hightest prize in mathematics. In this talk, we will briefly review the ideas of topology, discuss the specifics of the Poincare Conjecture, its history (including some of the many attempts to prove it), and the controversy surrounding its final proof.

**Time:**Thursday, November 1, 2007 3:00 p.m - 4:00 p.m.

**Location:**130 Solon Campus Center

**Modeling and Simulation: Systemic Approach**

Professor Seraphin Abou

UMD Department of Mechanical and Industrial Engineering

**Abstract:**

There are different approaches to develop mathematical models of a system. All of them depend on the purpose of the model. This presentation is based on the use of a "systems thinking" approach to analyzing and developing mathematical models of nonlinear systems. This means identifying the principle influencing the system's behavior in a holistic manner and estimating and/or verifying their impacts through testing and simulation. An application on mineral processing is illustrated. The approach allows subsequent extensions of the model to span multiple levels of evolution of the system's behavior.

**Time:**Thursday, November 8, 2007 3:00 p.m - 4:00 p.m.

**Location:**130 Solon Campus Center

**A Model Teacher-Scholar Program in Mathematics**

Professor David Barker and Professor Saad I. El-Zanati

Department of Mathematics Illinois State University

**Abstract:**

We give a preliminary report on the development, implementation and evaluation of a model teacher-scholar program in secondary mathematics. The yearlong program consists of two junior/senior level research capstone courses. In the first course, Introduction to Research in Mathematics (offered in the Spring), students explore several research topics (from the instructor's main research interest/expertise areas) with emphasis on experimentation, conjecture, careful justification, and clear, precise reporting. The second course, Research in Mathematics II (offered in the fall), places emphasis on further examination of specific research topics and on writing and disseminating results. The main objective of the program is to graduate teacher-scholars. Teacher-Scholars are highly qualified teachers who have experienced scholarship in mathematics in a setting that emphasizes the interconnections amoung theory, procedures, and applications and who "develop habits of mind of a mathematical thinker" (CBMS, 2001). A two-year run of the program is being supported by a grant from the Division of Undergraduate Education at the National Science Foundation. We report on the results from the first complete run, which was piloted in 2007.

**Time:**Monday, November 12, 2007 3:00 p.m - 4:00 p.m.

**Location:**130 Solon Campus Center

**Careers in Actuarial Science**

Alex Kranz, UMD 2006

Wesley Griffiths, UMD 2000

**Abstract:**

The Talk will cover the following topics:

- Where do actuaries work?
- What type of work are actuaries involved in?
- What skills do you need to be an actuary?
- What UMD classes will best prepare you for a job as an actuary?
- What are the actuarial exams all about?
- How do I get a job as an actuary?

**Time:**Thursday, November 15, 2007 3:00 p.m - 4:00 p.m.

**Location:**130 Solon Campus Center

**A 3-Dimensional Transient Kinetic-Diffusion Model of Nerve Regeneration**

Professor Gregory Rutkowksi

Department of Chemical Engineering, UMD

**Abstract:**

Upon injury to the peripheral nervous system, neurons receive physical and chemical cues from the microenvironment in order to regenerate by a process akin to that observed during embryonic development. The microenvironment consists of the extracellular matrix which provides structural and chemical support as well as diffusible molecules from noneuronal cells (Schwann cells) which control cellular processes. The combination of these factors in a dynamic state contributes to the overall regenerative process. In order to promote regeneratin, various bioartificial nerve grafts have been developed to mimic the microenvironment of the tissue. Concurrently, computer models have also been created to describe the regeneration process. These models consider the growth of axons as a stochastic process and do not take into account the dynamic interactions with the microenvironment.

Initial modeling efforts in our lab have focused on the steady state, one dimensional transport of nutrients and growth factors within a bioartificial nerve graft. In vitro studies have supported predictions from the model. Current work has shifted to the chemoattractive nature of nerve growth factor (NGF) secreted by Schwann cells. In a bioartificial nerve graft, these cells will have an impact on the microenvironment of the nerve tissue. A three dimensional transient model can be used to describe the distribution of NGF within the graft as well as predict axon extension in response to graients of NGF.

**Time:**Friday, November 30, 2007 3:00 p.m - 4:00 p.m.

**Location:**130 Solon Campus Center

**Actuarial Internship Presentation**

Matt Steffen - Travelers - P/C Insurance

Brian Rock - Securian - Health & Life Insureance

Bridget Huss - Hewitt Associates - Health Care Consulting

UMD Students

**Abstract:**

Ever want to know what to expect from an acturial internship? Well, here is your chance. Three UMD students will describe their 2007 summer actuarial internships. They will talk about the company they worked for, the actuarial field in which they worked, and also some specific projects they completed.

The presentations will be followed by a short a panel discussion. This will be a good time to compare and contrast the different areas of actuarial work and also find out about what to expect on the job or internship. So bring along your questions.

Also note:

The Math Colloquium will be followed by an Actuary Club meeting that will be hosted by Brad Diaz. Brad is a former UMD student working as an actuary for Reden & Anders. He will discuss what to expect in life after college, the health care consulting industry, and of course Reden & Anders. All are welcome to attend.

**Time:**Thursday, December 6, 2007 3:00 p.m - 4:00 p.m.

**Location:**130 Solon Campus Center

**Hamiltonian Circuits in the Direct Product of Two Cyclic Groups**

Rosa M. LeJeunesse

MS Candidate in Applied and Computational Mathematics

Advisors: Robert McFarland and Joseph Gallian

Department of Mathematics, UMD

**Abstract:**

In this talk I will demonstrate various techniques for finding closed circuits that pass exactly once through each element of a group represented as vertices on a 2-dimensional torus grid. We consider four variations on this problem according to whether the vertices of various subsets of the group are not on the circuit or the circuit passes through these vertices twice.

**Time:**Thursday, December 6, 2007 3:00 p.m - 4:00 p.m.

**Location:**130 Solon Campus Center

**Pear Tree; No Partridge (or why math has come late to biology)**

Jay A. Johnson

Professor Wood and Paper Science

University of Washington

**Abstract:**

I will discuss a problem I have worked on that was motivated by pure curiosity. It is about the shape of a pear tree branch bent excessively by the weight of a hanging fruit. It turns out the problem has a connection with elliptic functions; not the standard mathematics of biologists! I will use this problem to move into a discussion about the interaction of biology and mathematics. I'll also talk about two academic units at the University of Washington that focus on problems in the area of natural resources and ecology. The Center for Quantitative Science (CQS) provides alternative mathematics and statistics courses for undergraduates who are in biological curriculums and Quantitative Ecology and Resource Management (QERM) is a graduate program with faculty from several disciplines involved in research projects involving some form of mathematical modeling. In this talk, I will prove nothing; nor will I pass myself off as a mathematician. I am, however, very interested in teaching low level mathematics to students who may have never experienced the beauty of it all and I hope to inject some enthusiasm into my talk.

**Time:**Friday, December 14, 2007 3:00 p.m - 4:00 p.m.

**Location:**130 Solon Campus Center

**Comparison of Least Squares Method and Empirical Likelihood Ratio Method in Bifurcating Models**

Wenjie Xu

MS Candidate in Applied and Computational Mathematics

Department of Mathematics, UMD

**Abstract:**

Bifurcating autoregressive(BAR) processes are used to model the bifurcating cell lineage tree. Least squares estimate method and empirical likelihood ratio method can be used to construct confidence regions for parameters in the model. In this project we use monte carlo simulations to estimate the coverage probabilities for confidence regions based on the two methods and compare the accuracy of the two approaches.

**Time:**Friday, December 21, 2007 2:00 p.m - 4:00 p.m.

**Location:**130 Solon Campus Center

**Hard Problems: The Road to the World's Toughest Math Contest ( Documentary Film )**

Department of Mathematics, UMD

**Abstract:**

Hard Problems is a newly released 82-minute documentary film about the extraordinarily gifted students who represented the United States in 2006 at the world's toughest math competition--the International Mathematical Olympiad (IMO). It is the story of six U.S. high school students who competed with 500 others from 90 countries in Ljubljana, Slovenia. The film shows the dedication and perseverance of these remarkably talented students, the rigorous preparation they undertake, and the joy they get out of solving challenging problems. It captures the spirit that infuses the mathematical quest at the highest level. The film trailer is at http://www.hardproblemsmovie.com/

The film has several connections to UMD. One of the people in the film has visited UMD for the past seven summers; another one will be at UMD in the summer of 2008; the film's sponsor was at UMD in the summer of 1981; and the executive producer of the film has been at UMD since 1972.

After the film there will be free pizza. Students will receive two Math 3941 attendance points for this event.

**Time:**Thursday, January 31, 2008 3:30-5:00 Colloquium

**Location:**130 Solon Campus Center

**Mathematics by Engagement**

Angela Sharp

Instructor

Department of Mathematics, UMD

**Abstract:**

As a math educator, I have often wondered how to get my students more interested in math. To that end, I have looked for opportunities to engage students both physically and mentally with the concepts we are discussing in class. The result is a collection of activities I have used in an introductory calculus course. Some activities are hands-on and others provide the opportunity of ownership. I will present several of these activities, along with the supplies and required planning. Also, I will describe the students’ response to these activities.

**Time:**Thursday, February 7, 2008 3:00-4:00 Colloquium

**Location:**130 Solon Campus Center

**The Great Pi/e Debate (film)**

Department of Mathematics, UMD

**Abstract:**

As part of UMD's observance of Pi day, we show a film of a debate of the burning question that has plagued humankind from time immemorial: "Which is the better number, e or pi?" Williams College Professors Adams and Garrity use any means within their powers to prove their point. The debaters challenge orthodoxy, brazenly flaunt convention and behave rather badly in their attempts to convince the audience of the absolutely ridiculous nature of their adversary's arguments.

The genesis of both numbers is explained and the entire debate lasts 40 minutes. Which number is the superior number? Which number deserves to be held in the highest regard? You may already have your strongly felt opinions but get ready to have them stood on their heads when you watch the Great Pi/e Debate!

**Time:**Thursday, February 21, 2008 3:15-4:00 Colloquium

**Location:**130 Solon Campus Center

**Broken Symmetries**

Dr. Robert L. McFarland

Professor

Department of Mathematics, UMD

**Abstract:**

What do the following items have in common: wrenches, hair clippers, self-trimming candles, the development of the wheel, sailboats with canting keels, the Mona Lisa, Michelangelo de Caravaggio, the actress Hedy Lamarr (and her husbard George Antheil), electronic communications, some Nobel prizes in Physics, why Isaac Newton developed Calculus, mammalian brains, and some cognition (even in insects)?

In this talk I will try to convince you of the importance (and certainly the ubiquity) of the concept of broken symmetry, for that is the answer to the question posed above.

**Time:**Thursday, February 28, 2008 3:00-4:00 Colloquium

**Location:**130 Solon Campus Center

**Native Americans in Mathematics: a Proud Past, and a Look to the Future**

Dr. Robert E. Megginson

Professor of Mathematics

Associate Dean for Undergraduate and Graduate Education

College of Literature, Science and the Arts

University of Michigan

Ann Arbor, Michigan

**Abstract:**

Too many people believe that "Native American Mathematics" is almost an oxymoron, and that mathematics is an activity in which the Native people of the Western Hemisphere did not participate before the arrival of Europeans. In this talk, I will try to dispel that myth, and will even show how, arguably, a too-good knowledge of how to do mathematics by the Mexica (Aztec) people contributed to the European conquest of Central America! I will also discuss some of the barriers preventing more full participation of Native Americans in mathematics, again hoping to dispel some myths. I will end by talking about the opportunities now available to Native American people in mathematics-based fields, and why it is important for ourselves, our sovereign Indian nations, and the U.S. nation of which we are a part to pursue those opportunities.

This talk will be dedicated to the memory of Thomas F. Storer, Dine (Navajo), a friend, colleague, and role model for me. Tom was probably the first Native American to receive a Ph.D. in pure mathematics, and is greatly missed by all those he inspired.

**Time:**Thursday, March 6, 2008 3:00-4:00 Colloquium

**Location:**130 Solon Campus Center

**The Hibernating Heart: mathematical tools for some unsolved problems**

Marshall Hampton

Professor

Department of Mathematics, UMD

**Abstract:**

Hibernation in small mammals involves extreme physiological changes, as well as some puzzling dynamics. In a ground squirrel, heartrates can fall from 400 beats per minute to 3, and the core body temperature can plummet from 37 C to -3 C. Much smaller changes would be lethal in a non-hibernator - and the first thing to fail is the heart. How do the hibernators survive? Even more striking, every one to two weeks, hibernating mammals arouse to normal temperatures but do not eat or drink. This consumes most of their fat reserves. Why do they do it? These and other issues will be explored with a focus on how mathematics can help.

**Time:**Thursday, March 13, 2008 3:00-4:00 Colloquium

**Location:**130 Solon Campus Center

**Using Mathematica's Demonstration Project in the Calculus Classroom**

Angela Sharp and Chad Pierson

Instructors

Department of Mathematics, UMD

**Abstract:**

The proverb "A picture is worth a thousand words" conveys the fact that often times an image is the ideal way to communicate complex ideas. This happens to be precisely the case for several critical concepts in calculus. Mathematica 6.0 makes it easy to create dynamic visualizations designed to be used either in the classroom for instruction or accessed online by students at their leisure. We will show what is already available free from the Demonstration Project's website and how easy it is to create your own. This talk is accessible to anyone who has taken a calculus course and is intended for anyone who desires to teach mathematics.

**Time:**Thursday, March 27, 2008 3:00-4:00 Colloquium

**Location:**150 Chemistry Building

**How Much Does it Cost a Parasitoid to be Unmated?**

Richard Green

Professor

Department of Mathematics, UMD

**Abstract:**

Parasitic wasps (parasitoids) have the ability to choose the sex of their offspring. Mated female wasps can produce either sons or daughters, while unmated females can only produce sons.

Solitary parasitoids, which lay only one egg on each host, sometimes produce sons on smaller hosts and daughters on larger hosts. In 1979 Eric Charnov proposed a model to explain this host-size effect.

If some females are unmated and produce only sons, then mated females should produce more daughters than they should if all other females are mated. In 1990 Charles Godfray showed exactly how the sex ratio of offspring from meted females should depend on the proportion of females that are unmated. However, Godfray did not consider the host-size effect.

In this talk I will show that if daughters benefit more from being produced in large hosts than do sons, then there is a cost of being unmated. I will show how to measure this cost by using a method that I described in 1982 for treating the host-size problem.

I will also make some comments about sex ratios in general and about parasitoid sex ratios in particular.

**Time:**Thursday, April 3, 2008 3:00-4:00 Colloquium

**Location:**130 Solon Campus Center

**Basic Image Compression with Wavelets**

Patrick VanFleet

Department of Mathematics

Professor and Director

Center for Applied Mathematics (CAM)

University of St. Thomas

St. Paul, Minnesota

**Abstract:**

In this talk, we will describe a basic algorithm for performing digital image compression. A digital image can be viewed as a matrix of integer entries ranging from 0 (black) to 255 (white) inclusive. One of the steps in an image compression algorithm is to apply a linear transformation to the image matrix in hopes of improving the overall effectiveness of the algorithm. The popular JPEG standard uses the so-called discrete cosine transformation (DCT), but for a variety of reasons, the discrete wavelet transformation replaced the DCT in the revised JPEG2000 standard. We will provide a very elementary introduction to the discrete Haar wavelet transformation and discuss how it affects the compression algorithm. The talk will conclude with a construction of a discrete wavelet transformation used in the JPEG2000 standard. Students who know how to multply matrices will understand the entire talk.

**Time:**Thursday, April 10, 2008 3:00-4:00 Colloquium

**Location:**150 Chemistry Building

**The Truth of Natural Numbers**

Professor Yixin Zhu

School of Mathematical Science

Capital Normal University

Beijing, China

**Abstract:**

In this talk, I am going to talk about the truth of natural numbers in real life from the point of view of arithmetic operation of numbers.

**Time:**Thursday, April 17, 2008 3:00-4:00 Colloquium

**Location:**150 Chemistry Building

**Mathematics and Law Enforcement**

Sergeant Nicholas Alexander

Patrol Sergeant/Computer Forensics

Superior Police Department

**Abstract:**

Mathematics can be applied in all walks of life. Many times we take math's role in everyday situations for granted, or simply fail to recognize the application of it. Mathematics plays a significant role in many law enforcement related activities such as speed enforcement, forensic sciences, accident reconstruction, and computer forensics. We will explore how math applies to these situations and how it is valuable in law enforcement. As a result we will see why people with math and science backgrounds have become in more demand in law enforcement employment.

**Time:**Thursday, April 24, 2008 3:00-4:00 Colloquium

**Location:**150 Chemistry Building

**Stefan Banach and "The Scottish Book"**

Sylwia Cichacz

Fulbright Junior Scholar

AGH University

Science and Technology

Crocow, Poland

**Abstract:**

I would like to talk about a Polish mathematician who founded the important modern mathematical field of functional analysis and made contributions to the theory of topological vector spaces. In addition, he contributed to measure theory, integration, the theory of sets and orthogonal series.

In 1935, a large notebook was purchased by Banach's wife and deposited with the head waiter of the "Scottish Cafe," a restaurant frequented by Polish mathematicians like S. Ulam, S. Banach, S. Mazur, H. Steinhaus, and W. Orlicz. In this book they, and occasional visitors like Henri Leon Lebesque and John von Neumann, recorded open problems for any customer to solve. Some of the problems were solved immediately or shortly after they had been posed. A quarter of the problems remain unsolved to this day. A collection of 193 mathematical problems resulted from the meetings at the Scottish Cafe and appeared later on as the "Scottish Book."

**Time:**Thursday, May 1, 2008 3:00-4:00 Colloquium

**Location:**130 Solon Campus Center

**Honors Colloquium**

Speakers:

Laura Hoffman: "Reform Versus Traditional Mathematics"

Kathleen Malevich: "Are Placement Tests for Mathematics Working?"

Matthew Steffen: "Statistical Arbitrage: Developing a Pairs Trading Model"

Garrett Taft: "In Search of the Sunniest Day"

Shawn Walwick: "Q-Binomial Coefficients"

**Abstract:**

Five undergraduate students in the Department of Mathematics and Statistics are graduating with honors this year. Students must complete a research project under the supervision of a department faculty member in order to qualify for Departmental Honors. Each student will give a 10-minute presentation about his or her research project.

**Time:**Friday, May 2, 2008 3:00-4:00 Colloquium

**Location:**120 Solon Campus Center

**The Math Behind Some Computerized Puzzles**

John Kiltinen

Professor Emeritus

Department of Mathematics

Northern Michigan Univeristy

**Abstract:**

In this talk I will discuss some puzzle software I have written that was published by the Mathematical Association of America and some of the mathematics needed for understanding them. No background in advanced mathematics required. I will also discuss some easily understood open mathematical questions that the puzzles raise.

**Time:**Thursday, May 6, 2008 3:00-4:00 Colloquium

**Location:**Chemistry Building 251

**Polish System of Education**

Sylwia Cichacz

UMD Visiting Researcher

AGH University of Science and Technology

Crocow, Poland

**Abstract:**

The European education system is structured differently than the American system. I will use the Polish system as an example to show how it works. For instance, school is mandatory until age 18 and public universities provide free secondary education. I will explain how this affects skill levels at universities.

**Time:**Thursday, May 8, 2008 3:00-3:50 Colloquium

**Location:**Chemistry Building 151

**Dynamic Efficiency for a Nonrenewable Resource Market with Variable Demand**

Riitta Schaublin

MS Candidate in Applied and Computational Mathematics

Department of Mathematics, UMD

**Abstract:**

In defending my Master's research project, I will use optimal control theory to derive the socially efficient allocation of a nonrenewable natural resource given that its demand is altered by the availability of an increasingly less costly renewable substitute.

The research was motivated by society's drive to reduce oil consumption and rely on environmentally more sustainable renewable energy reources like ethanol. In developing the models for this energy market, a general overview for measureing social efficiency is provided.

**Time:**Thursday, May 13, 2008 2:00-4:00 Colloquium

**Location:**Solon Campus center 130

**Support Vector Machines**

Brad Jannsen

MS Candidate in Applied and Computational Mathematics

Department of Mathematics, UMD

**Abstract:**

Machine learning is the process in which an algorithm improves or "learns" through experience. Machine learning has its roots in artificial intelligence and is a topic that has received increasing attention over the last few years. One method in particular, support vector machines, has become the standard by which other machine learning methods are compared. The idea behind support vector machines is to separate the data in some "optimal" method. In this talk, I will discuss how this optimality is satisfied, introduce required background information along with the underlying theory, and discuss advantages and disadvantages of support vector machines.

**Time:**Wednesday, May 28, 2008 1:00-2:00 Colloquium

**Location:**Solon Campus center 130

**VERIFYING AND DISCOVERING BBP-TYPE FORMULAS**

Melissa Larson

MS Candidate in Applied and Computational Mathematics

Advisor: John Greene

Department of Mathematics, UMD

**Abstract:**

In 1995, the formula was discovered. It became known as the BBP formula, named after David Bailey, Peter Borwein, and Simon Plouffe. The formula permits the calculation of the nth binary digit of pi without calculating the preceding n-1 digits. Since its discovery, formulas of similar form have been found and are known as BBP-Type formulas. In this talk, I will describe useful "tricks" for verifying BBP-Type formulas. I will show how to use the tricks to verify the previously discovered BBP-Type formulas, prove a conjectured formula, and how to search for BBP-Type formulas.

**Time:**Wednesday, June 4, 2008 1:00-3:00 Colloquium

**Location:**Solon Campus center 130

**VERIFYING AND DISCOVERING BBP-TYPE FORMULAS**

Katherine Niedzielski

MS Candidate in Applied and Computational Mathematics

Advisor: John Greene

Department of Mathematics, UMD

**Abstract:**

Given the difference equation it is known that when x = 1/2, 1/3 or 1/5, periodic solutions exist. Are there other positive rational values of x for which periodic solutions exist? What about negative rational values? In this talk, I will discuss my search for rational value of x which do lead to periodic solutions. I used a method which involved searching for products of two matrices, I will discuss why this method works and the result I found.

**Time:**Thursday, June 5, 2008 1:00-3:00 Colloquium

**Location:**Solon Campus center 130

**A STOICHIOMETRIC MODEL OF TWO PRODUCERS AND ONE CONSUMER**

Laurence H. Lin

MS Candidate: Program in Applied and Computational Mathematics

Advisors: Bruce Peckham, Harlan Stech, John Pastor

Department of Mathematics and Statistics

UMD

**Abstract:**

A stoichiometric population model of two producers and one consumer is a generalized case of the Rosenzweig and MacArthur model, which is a single producer and single consumer population model without stoichiometry. The generalization involves two steps: 1) to add a second producer and 2) to introduce stoichiometry into the system. Both generalizations give additional equilibria and bifurcations to the single producer model without stoichiometry. The primary focus of this research is to study the equilibria and bifurcations of the two-producer model with stoichiometry. The model in this paper is nutrient closed. The primary parameters are the growth rates of both producers, and the secondary parameter is the total nutrient in the system.

**Time:**Thursday, June 12, 2008 1:00 p.m - 3:00 p.m.

**Location:**Solon Campus center 130

**What Makes a Champion? A Multivariate Analysis of Major League Baseball**

Lindsey Dietz

MS Candidate in Applied and Computational Mathematics

Department of Mathematics, UMD

**Abstract:**

Who has the best chance of winning the World Series this year? There are many who would love to predict the outcome of the Major League Baseball season with some degree of accuracy. A field of study known as sabermetrics, is dedicated to queries like these. Sabermetrics is defined as the analysis of baseball through objective evidence, especially statistics. In this project, sabermetric tools, such as the Pythagorean Expectation, as well as one of the conventional statistical methods, linear regression, are used to help answer the question of success in baseball.

**Time:**Tuesday, June 24, 2008 3:00-4:00 Colloquium

**Location:**Solon Campus center 130

**Design and Analysis of RT-PCR Measurements for RNA Expression**

Feng Qian

MS Candidate in Applied and Computational Mathematics

Department of Mathematics, UMD

**Abstract:**

In this paper, the methods used in the data analysis of Real-Time Polymerase Chain Reaction (RT-PCR) were described. First, the use of a reference gene and how to choose the best reference gene using BestKeeper Software were discussed. Secondly, three methods of testing treatment effects were described: Relative Expression Software Tool(REST), T-Test, and Analysis of Covariane(ANCOVA). These methods were tested using data sets from the University of Minnesota Duluth(UMD) Medical School. ANCOVA method gave the best results among the three methods. Finally, useful recommendations were made to the medical school researchers regarding RT-PCR data analysis.

**Time:**Thursday, July 3, 2008 12:00-1:00 Colloquium

**Location:**Solon Campus center 130

**Wavelet-based Bootstrap and Its Application to Option Pricing**

Junyan Shen

MS Candidate in Applied and Computational Mathematics

Department of Mathematics, UMD

**Abstract:**

What is option? Option is a flexible financial product, which can reduce investment risk. Lots of math models are set up to determine the option price, among which the Black-Scholes model is the most famous. In my project, I used the simulation to price the option. As the core of my simulation, wavelet-baseed bootstrap is useful to generate a large number of long memory time series. The method consists of two important statisitcs ideas: wavelet transform and bootstrap. Both methods are studied, and the wavelet-based bootstrap algorithm is established. The simulation performs well in estimating the option price.

**Time:**Saturday, July 5, 2008 1:00-3:00 Colloquium

**Location:**Solon Campus center 130

**Sex ratios in parasitic wasps**

Dick Green

Department of Mathematics, UMD

**Abstract:**

The study of sex ratios and, more generally, sex allocation has provided some of the most successful examples of modern evolutionary theory. Many Hymenoptera (bees, ants and wasps) have the ability to determine the sex of their offspring: unfertilized eggs become sons while fertilized eggs become daughters. I will describe several ways in which parasitic wasps use their ability to choose the sex of their offspring in order to solve problems presented by nature. I am particularly interested in how mated female wasps should allocate the sexes of their offspring to hosts of different sizes when some females are unmated and produce only sons. This talk uses mathematical and statistical ideas that are familiar to anyone who has taken the first courses in those subjects.

**Time:**Thursday, September 18, 2008 3:00-4:00 Colloquium

**Location:**Solon Campus center 130

**Provably Hard and Provably Impossible Tasks**

Steve Rosenberg

Associate Professor

University of Wisconsin--Superior

Mathematics and Computer Science Department

**Abstract:**

Did you ever feel frustrated by a math problem? Are some problems really "harder" than others? Yes! By making the notion of task precise and then measuring quantitatively how efficiently each type of task can be accomplished, we arrive at a notion of the intrinsic level of difficulty of a problem. We can even prove that some types of problem are impossible to solve, in the sense of finding a procedure that works every time. For those in the know: we will be talking about formal algorithms, time-complexity, and the Halting Problem. In some small way, these results can comfort us in the future when we feel that our problems are too hard! No special knowledge of computer science is assumed.

**Time:**Thursday, September 25, 2008 3:00-4:00 Colloquium

**Location:**Solon Campus center 130

**My Life with the Queen**

William A. Lokke

Former Deputy Director of the Lawrence Livermore National Laboratory

Departmental nominee to the SCSE Academy

Livermore, California

**Abstract:**

Mathematics is often called the queen of science. Besides its traditional role in structuring theory, mathematics in its pure form can also be directly beneficial to the other sciences. Alan Turing.s insight in considering Hilbert.s decision problem, which led to today.s pervasive computer, delivered perhaps the greatest gift the field has yet given to science. In tracing my history of service to science.s king, physics, at California.s Lawrence Livermore National Laboratory, I will point out the crucial role computing has played in my career and in the laboratory.s many programs - particularly nuclear weapons. I will present a model for making most effective use of computing, describe some interesting challenges awaiting its application, and admit to certain difficult mathematical obstacles to be overcome.

**Time:**Friday, October 3, 2008 3:30- Colloquium

**Location:**Chemistry 150

**Actuarial Summer Intern Experiences**

Jeff Anderson

Dan Boeder

Shannon Glonek

Brian Hinkle

UMD

**Abstract:**

Four UMD students will present about their experiences as actuarial summer interns this summer in the Twin Cities. They will talk about topics ranging from the job search, to interviewing, to the projects they worked on over the summer. There will also be a question and answer period at the end of the presentations. The interns and their companies are Jeff Anderson, Securian Financial; Dan Boeder, CG Consulting; Shannon Glonek, Thrivent Financial; and Brian Hinkle, Securian Financial.

**Time:**Thursday, October 9, 2008 3:00-4:00 Colloquium

**Location:**Solon Campus Center 130

**FUNCTIONAL LOCALIZATION OF CALCIUM HANDLING MACHINERY**

Steven J. Cox

Department of Computational and Applied Mathematics

Rice University

Houston, Texas

**Abstract:**

Calcium, the most important of the second messengers, sculpts and records synaptic input and modulates the excitability of both nerve and muscle. We exploit the recent ability to dynamically monitor cytosolic calcium, throughout rat hippocampal pyramidal cells in slice, with sub-millisecond temporal resolution and sub-micron spatial resolution in the construction of a functional map of calcium and potassium channel density.

In the process we pose and solve a number of inverse problems associated with dye recordings following focal uncaging of intracellular calcium and suprathreshold current injection. In particular, we 1) Infer from the change in cytosolic dye-buffered calcium fluorescence the dye binding rates and the calcium pump rate. 2) Infer from (1) the calcium current associated with back propagating action potentials and infer from this the associated channel densities.

**Time:**Thursday, October 16, 2008 3:00-4:00 Colloquium

**Location:**Solon Campus center 130

**Free Math! The Sage software project for free and open-source computation**

Marshall Hampton

UMD Mathematics Department

**Abstract:**

Three years ago William Stein released the first version of Sage, a free and open source computational platform based on the popular scripting language Python. Sage unifies a huge collection of mathematical software projects into a coherent and powerful system for mathematics, statistics, and scientific computation. In this talk I will give a brief overview of its present capabilities and future directions.

**Time:**Thursday, October 30, 2008 3:00-4:00 Colloquium

**Location:**Solon Campus center 130

**MACHINE LEARNING VIA BILEVEL OPTIMIZATION**

Gautam Kunapuli

Postdoc

University of Wisconsin - Madison

**Abstract:**

Support Vector Machines have been applied with great success in machine learning. Support vector classification and regression are usually formulated and regarded as convex machine learning problems. However, the use of these methods entails solving several other related problems such as parameter and feature selection in conjunction with the central machine learning problem.

In fact, these problems are far from being convex: they depend on hyper-parameters like the regularization parameter and the kernel parameter whose optimal values need to be determined judiciously in order to get the best generalization behavior. When viewed from the perspective that the hyper-parameters are also variables in the model, the machine learning task becomes non-convex.

A novel approach is proposed where in cross validation is formulated as a continuous bilevel program which is a mathematical program whose constraints are functions of optimal solutions of another mathematical program. This powerful approach unifies parameter and feature selection into the central task of learning such that it is possible to simultaneously determine, not only the optimal model, but also the optimal parameters and features. Numerical results demonstrate that this approach is superior to conventional grid search approaches.

**Time:**Thursday, November 6, 2008 3:00-4:00 Colloquium

**Location:**Solon Campus center 130

**Pricing and the Central Limit Theorem**

Scot Adams

Professor of Mathematics

University of Minnesota Twin Cities

**Abstract:**

We'll discuss "risk-neutral" pricing and how that concept combines with the Central Limit Theorem to lead to Black-Scholes.

Note: Professor Adams is the director of the Financial Mathematics program at UMNTC and will be happy to discuss that program with interested students

**Time:**Monday, November 10, 2008 3:00-4:00 Colloquium

**Location:**Solon Campus center 130

**The daily life of an actuary**

Brad Diaz

Actuary at Ingenix/Redden and Anders

**Abstract:**

Brad Diaz is a UMD graduate and an actuary at a health care consulting firm that is part of United Health Group. He will talk about the everyday responsibilities of a health care actuary, the implications of a consulting role in the health care sector, and the importance of actuarial exams. There will also be time for questions at the end.

**Time:**Thursday, November 20, 2008 3:00-4:00 Colloquium

**Location:**Solon Campus center 130

**GLOBAL EXISTENCE AND STABILITY OF A QUASILINEAR WAVE EQUATION**

Professor Qiong Zhang

Department of Mathematics

Beijing Institute of Technology

**Abstract:**

A degenerate nonlinear dissipative wave equations of Kirchhoff type with boundary damping is studied. We prove that this system has a unique global solution if the initial data satisfied suitable assumption. We also reach the polynomial decay of solution of the system.

** Time: ** Friday, December 12, 2008 4:15-

** Location: **Solon Campus center 130

**GENERALIZED ADDITIVE MODEL (GAM)**

Huimin Liu

MS Candidate: Program in Applied and Computational Mathematics

Advisor: Kang James

Department of Mathematics and Statistics

UMD

**Abstract:**

For years, researchers have been relying on Generalized Linear Model (GLM) to do their everyday research. As great as GLM is, it does not work in every situation; it fails to capture the nonlinearity in some cases, and therefore possibly not leading to satisfactory results. Generalized Additive Model (GAM) is introduced to compensate some of the disadvantage associated with GLM. In my presentation, the basic theory of GAM by Hastie and Tibishirani will be introduced. The advantage of GAM will be illustrated by examples. The fitting of GAM using SAS will be discussed. In addition, Generalized Additive Logistic Model together with an example will be given.

**Time:**Thursday, December 18, 2008 2:00 p.m. - 3:00 p.m.

**Location:**Solon Campus center 130

**Using Mathematics to Create Symmetry Patterns**

Joe Gallian

University of Minnesota Duluth

**Abstract:**

We use video animations to illustrate how mathematics can be used to create computer generated symmetry patterns. Discrete math, exponential functions, logarithms and modular arithmetic are used to transform basic images into symmetry patterns. These methods were used to create the image for the 2003 Mathematics Awareness Month poster. The talk is intended for a general audience.

**Time:**Thursday, February 5, 2009 3:00--4:00

**Location:**130 Solon Campus Center

**Benford's law, or the first digit phenomenon**

Dick Green

UMD Department of Mathematics and Statistics

**Abstract:**

When written in decimal form, almost all real numbers have approximately equal concurrences of the digits 0, 1, 2,..., 9. The leading digit cannot be 0, but one might expect that numbers encountered in the world would be equally likely to begin with each of the digits, 1, 2, 3,..., 9. However, for many kinds of data (stock prices, street addresses, river lengths) the leading digit is more often 1 than 2, more often 2 than 3 and so on. In 1938, Frank Benford proposed a distribution for first digits that follows the distribution of their common logarithms. I will describe Benford's law and explain why it is often likely to hold, at least approximately. I will talk about other empirical laws related to Benford's, including those of Zipf and Lotka, and I will say a few words about eponymous "laws" like "Benford's".

**Time:**Thursday, February 19, 2009 3:00--4:00

**Location:**130 Solon Campus Center

**CLASSICAL MARKOV CHAINS: A UNIFYING FRAMEWORK FOR UNDERSTANDING AVIAN REPRODUCTIVE SUCCESS**

Mathew Etteson, Ecologist

U.S. Environmental Protection Agency

Duluth, Minnesota

**Abstract:**

Traditional methods for monitoring and analysis of avian nesting success have several important shortcomings, including 1) inability to handle multiple classes of nest failure, and 2) inability to provide estimates of annual reproductive success (because birds can, and typically do, make multiple nest attempts in a year). Both of the above limitations may be relaxed by treating the avian nesting process as a Markov chain. In the first case the transition matrix is assumed unknown and maximum likelihood estimates for the transition probabilities are easily obtained. In the second case the asymptotic behavior of Markov chains may be used to gain remarkable insight from fairly simple hypotheses about the transition probabilities. With the above underpinnings, I will describe and demonstrate time-hetergeneous Markov chain models that we are currently developing at the EPA lab here in Duluth. Our primary objective in developing these models is to provide a regulatory tool for integrating laboratory testing data on adverse reproductive effects with avian life history information to inform ecological risk assessments.

**Time:**Thursday, February 26, 2009 3:00--

**Location:**130 Solon Campus Center

**Some Math Behind M.C. Escher's "Circle Limit" Patterns**

Doug Dunham

UMD Department of Computer Science

**Abstract:**

The Dutch graphic artist M.C. Escher was the first person to create designs that could be interpreted as repeating patterns in the hyperbolic plane. He called them "Circle Limit" patterns since they were drawn inside a circle and had motifs that grew ever smaller as they approached that bounding circle. Some mathematicians have analyzed the symmetries of these patterns, giving their symmetry groups, which we will explain. The "Circle Limit IV" pattern seems to be mis-oriented frequently. We will show the correct orientation. Finally, we will show how to make your own circle limit patterns using mathematics and computer graphics.

**Time:**Thursday, March 5, 2009 3:00--4:00

**Location:**130 Solon Campus Center