-------------------------------------------------------------------- COLLOQUIUM OF THE COMPUTATIONAL MATERIALS SCIENCE CENTER AND THE SCHOOL OF PHYSICS, ASTRONOMY, & COMPUTATIONAL SCIENCES (CSI 898-Sec 001) -------------------------------------------------------------------- What do noisy datapoints tell us about the true signal? Charles Hogg III National Institute of Standards and Technology, Gaithersburg, MD Every measurement has uncertainty which needs to be quantified. Bayesian approaches achieve this naturally, by expressing results in terms of probabilities. I will give a conceptual overview of Bayesian analysis for metrological applications. This includes a discussion of Occam's razor, a helpful but qualitative dictum that is clarified and quantified when recast in the language of probability. Three example systems will illustrate these concepts: finding the true X-ray diffraction curve from noisy count data, interpolating the strain field of a stretched metal plate, and measuring aggregate uncertainty in flame speed datasets. All these systems require us to calculate probabilities for arbitrary smooth functions without assuming a functional form, and I will illustrate one tool (Gaussian Processes) which lets us do this in a Bayesian context. Having quantified the uncertainty, I will also show several ways to represent it, including smooth animations of sequences of candidates for the true signal. October 15, 2012 4:30 pm Room 301, Research I, Fairfax Campus Refreshments will be served at 4:15 PM. ---------------------------------------------------------------------- Find the schedule at http://www.cmasc.gmu.edu/seminars.htm