|Christian G J Roettger
Office 463 Carver
Amongst other things, I am interested in
Rashomon - Reconstructing Reality
from inexact measurements
Joint work with H Hofmann, D Cook.
MAA section meeting, Graceland University, Lamoni, IA, Oct 3, 2015
The art installation 'Rashomon' was displayed on the Iowa State University campus during summer 2015. It consists of 15 identical, abstract sculptures. Artist Chuck Ginnever posed the challenge whether it is possible to display the sculptures so that no two of them are in the same position (modulo translation/rotation). We investigated the related question of reconstructing such a sculpture from (ordinary tape-measure) inexact measurements. Mathematics involved are the Cayley-Menger determinant, and the gradient method / Steepest Descent. We'll explain the mathematics with some simple examples and then show the results of our reconstruction. We will only assume elementary linear algebra (matrix - vector multiplication, determinants).
Visual Hypothesis Testing - Lineups and Probability
MAA section meeting, Clarke University, Dubuque, IA, Oct 14, 2014
Police use lineups involving one suspect and several 'dummies' to get evidence that a witness can identify the suspect. In an abstract sense, we can form a hypothesis about 'suspect' data and test it in this way: literally have people looking at a lineup of plots with the task of identifying the data plot among the dummies. Repetition with several observers makes this approach surprisingly powerful. It also has potential when comparing the efficiency of different visual representations of the same data. Disclaimer: do not expect analysis of actual police lineups. But we will try out the method on the audience! This is joint work with Heike Hofmann, Di Cook, Phil Dixon, and Andreas Buja. I have investigated the underlying probability distributions. This meant evaluating some multiple integrals, and revising all the tricks from Calculus II.
Math 166: Calculus II (recitations only)
Math 265: Calculus III
Math 105: Introduction to Mathematical Ideas.We examine the mathematics of voting systems.
Math 141/142 Trigonometry (and analytic geometry)
Math 151: Calculus for Business and Social Sciences
Math 165: Calculus I
Math 166H: Honors Calculus II
Math 181: Calculus For the Life Sciences I (needs some updating)
Math 195: Math for Elementary Education
Math 267: Differential Equations, Laplace Transform
Math 297: Intermediate Topics in Elementary Mathematics
Math 301: Algebra I
Math 307: Matrices and Linear Algebra
Math 314: Graphs and Networks
Math 317: Theory of Linear Algebra
Math 350: Elementary Number Theory
Course notes for Analytic Number Theory
My Favorite Quote:"Should array indices start at 0 or 1? My compromise of 0.5 was rejected without, I thought, proper consideration." - Stan Kelly-Bootle
Pros and cons of metric vs imperial system.
This webpage is http://www.public.iastate.edu/~roettger/homepage.html