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Seminar and Colloquia
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.
John Pastor Professor of Biology University of Minnesota Duluth Abstract: There is much discussion about sustainability of natural resources and whether we are approaching so-called tipping points where systems change abruptly and become unsustainable. Mathematics can help us think more clearly about these problems. The mathematical ideas underlying "sustainability" and "tipping points" are equilibrium, stability, and bifurcations. I will show how these help us understand whether different harvesting policies of a population are sustainable. The unharvested population will be described by a logistic growth curve, from which we will subtract various functions representing different harvesting strategies. Different equilibria with different stabilities result. Various bifurcations happen at particular levels of harvesting where populations may go extinct or collapse to low levels. The underlying theory makes use of differential equations, but I will demonstrate the basic ideas graphically. Time: Thursday, September 24, 2009 3:00PM -- 4:00PM Location: 130 Solon Campus Center Michael Hafeman Abstract: I will provide an overview of my varied career as an actuary. I will begin with a description of my current activities as an independent consultant on financial sector regulatory issues. This will be followed by a discussion of the path taken to get there and some lessons learned along the way. An example will be used to illustrate how these lessons apply to a specific current activity--participation on the Public Interest Oversight Board. The objectives of the session will be to provide some insight on the range of opportunities available to actuaries and some ideas on factors that can contribute to career success. There will be opportunity for questions and discussion. Michael Hafeman is a 1974 graduate of UMD with degrees in mathematics and economics. He has assessed the insurance sectors of several countries for the International Monetary Fund and managed the development of comprehensive training materials on insurance supervision for the World Bank. He previously directed the Specialist Support Sector experts in Accounting and Financial Information, Actuarial, Capital, Capital Markets, Compliance, Credit Risk and Financial Services Technology, and oversaw the Office of the Chief Actuary, at the Office of the Superintendent of Financial Institutions Canada. He will be inducted into the Swenson College of Science & Engineering Academy of Science & Engineering while on campus. Time: Friday, October 2, 2009 3:00PM -- 4:00PM Location: LSBE 118 Dick Green Department of Mathematics and Statistics Abstract: An average is one number that stands for a bunch of other numbers when one is doing something with them. There are many kinds of averages. Not only do different numbers produce different averages, but the same numbers produce different averages when different things are being done with then. Various kinds of averages will be illustrated with examples including the rate of tuition increase at UMD, family size, generation time and the Ortega hypothesis about scientific productivity. This talk will be accessible to anyone who has had a basic course in statistics. Time: Thursday, October 8, 2009 3:00PM -- 4:00PM Location: 130 Solon Campus Center Steve Rosenberg Associate Professor, Department of Mathematics and Computer Science, University of Wisconsin-Superior Abstract: Usually introduced in second-year calculus, the Jacobian determinant associated with a smooth mapping carries much information about the mapping. In this introductory talk, we will explore polynomial mappings f : C[x1,...,xn] --> C[x1,...,xn] and investigate what the Jacobian J(f) tells us about f; e.g., when is f injective? Surjective? In the process, we will survey some basic results in commutative algebra and algebraic geometry. Steve Rosenberg has published results in number theory, discrete mathematics, and cryptographic protocol security. His current research interests include complex algebraic geometry, kswappable graphs, and diophantine approximation. Time: Thursday, October 15, 2009 2:45PM -- 4:00PM Location: 130 Solon Campus Center Natasha Farooq, Brian Hinkle, and Leah Tollefson UMD Department of Mathematics and Statistics 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 Leah Tollefson, and a discussion of the day-to-day activities of an actuary at Securian by Brian Hinkle. 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 theactuarial sciences? What does Securian do? Time: Tuesday, October 20, 2009 3:00PM -- 5:00PM Location: 130 Solon Campus Center Marshall Hampton UMD Department of Mathematics and Statistics Abstract: Biological data has been growing exponentially for the last few decades. The resulting wealth of data requires new mathematical, statistical, and computational methods. This talk will survey some of these methods, highlighting recent developments in sequencing mammalian genomes, the structure of the HIV virus, and the recent H1N1 swine-flu pandemic. Time: Thursday, October 22, 2009 2:45PM -- 4:00PM Location: 130 Solon Campus Center Michael Renardy Professor, Department of Mathematics, Virginia Tech Abstract: "Traditional" hydrodynamic stability studies infer stability of a flow from a computation of eigenvalues of the linearized system. While this is well justified for the Navier-Stokes equations, no rigorous result along these lines is known for general systems of partial differential equations; indeed there are counterexamples for lower order perturbations of the wave equations. This lecture will discuss how recent results on "advective" equations can be applied to creeping flows of viscoelastic fluids of Maxwell or Oldroyd type. For spatially periodic flows, stability can be reduced to the study of a) the eigenvalues, and b) a system of non-autonomous ordinary differential equations that arises from a geometric optics approximation for short waves. A more complete result for the upper convected Maxwell model will also be discussed. Michael Renardy has published 4 books, 164 research journal papers, 40 conference proceeding papers, and 24 papers on problem solving. He is a winner of several awards, like Presidential Young Investigator Award (1985), Virginia Tech Alumni Award for Research Excellence (1993), and Class of 1950 Professor, Department of Mathematics, Virginia Polytechnic Institute and State University. Time: Thursday, October 29, 2009 2:45PM -- 4:00PM Location: 130 Solon Campus Center Hanna Froehlich and Leah Tollefson UMD Department of Mathematics and Statistics Abstract: UMD mathematics majors Hanna Froehlich and Leah Tollefson will tell of their experiences studying abroad last spring semester. Hanna Froehlich, who studied at Loughborough University in Loughborough, England, took Fourier analysis, partial differential equations, calculus of variations, statistical modeling, numerical methods and complex variables. Leah Tollefson, who studied at the Norwegian University of Science and Technology in Trondheim, Norway, took partial differential equations, political economy, Norwegian ethnography, and Norwegian language. Each will describe her exchange program, course work, classroom culture and student behavior, making friends and holiday travel. They will answer questions, give advice and encourage others to also study abroad. Time: Thursday, November 5, 2:45PM -- 4:00PM Location: 130 Solon Campus Center Brian Hinderliter, Ph.D, CHP Coatings and Polymeric Materials Department, North Dakota State University Abstract: Coatings cover most metal and wood surfaces exposed to environmental weathering, both to protect the underlying material, from corrosion for example, and offer aesthetic improvements. Insights into coating degradation have been achieved first through Monte Carlo simulations, then through the recognition that many of the property changes are due to the statistical accumulation of vast numbers of small random events, allowing the central limit theorem (CLT) to be used to predict topological roughness distribution as a function of time. Simulation of coatings and other composite material degradation continues to be productive, not only in generating functional quantitative relationships of measurable properties with time, but also in helping to direct research to improve the technology. The modeling process payoffs include practical benefits such as the ability to interpolate measurements and smooth noisy data based on physically based fitting functions and extrapolate measured data for lifetime prediction or service/maintenance scheduling. Modeling is vital in more fundamental improvements of composite systems such as understanding the physical processes and composite constituents that are impacting measurement leads to better design of coatings (Occam?s razor ? know what is important for the property of interest), separating various degradation processes (chemistry from topography), and detecting changes in the dominant cause of measurement (for example detecting coating crack initiation in the paint). Success in understanding and predicting coating?s properties has been achieved with surface degradation in homogenized materials, both using statistical equations and Monte Carlo simulations. Many aspects of a coatings performance are impacted the surface topology, and with the temporal response function of the surface roughness based on CLT approximation, closed functional forms can the evolution of the surface reflectance as a function of wavelength, the surface energy and the probability of cracks developing in the coating. Time: Tuesday, November 10, 2:45PM -- 4:00PM (Note: this is not the usual day) Location: 130 Solon Campus Center Bryan Freyberg Math Teacher, Marshall School, Duluth Abstract: Fifty percent of new teachers walk away from the job within the first five years. I just needed a break. This talk is aimed at undergraduate and graduate students who may be considering a career in secondary education or applying for the NSF GK-12 Fellowship offered at UMD. I did both and lived to tell about it. I'll share some stories about teaching, information about the GK-12 program, and leave plenty of time for questions. Time: Thursday, November 19, 2:45PM -- 4:00PM Location: 130 Solon Campus Center |
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