Advisor : Charles (Chip) Lawrence

Interests:

Over the last 5 million years, the Earth's glaciers have melted and reformed at fairly regular intervals. The timing is thought to be determined by the amount of solar insolation received at the top of the Earth's atmosphere - a quantity that changes with the position of the Earth in its orbit around the Sun. This motion can be described by three parameters: obliquity (tilt), precession (wobble), and eccentricity (ellipticity). Eccentricity controls the absolute amount of insolation, whereas obliquity and precession control the distribution of insolation on the Earth's surface.

However, the glacial record exhibits times of drastic change, both in the size and frequency of glacial events. To determine the timing and and nature of these changes, a dynamic programming change point model in the context of posposed glacial models, from the simple linear regression-type models, to the more complex dynamics-based and Bayesian models, was used to analyze this time series. Change Point in conjunction with variable selection led to the development of a graphical model to increase the efficiency of calculations. By using a binary tree, the compute time of a variable selection problem can be reduced by 50-75% or more depending on the size of the problem, over brute force methods. My other research interests include Genome Wide Association Studies in the context of Phasing Algorithms and measures of Linkage Disequilibrium, as well as applications of Information Theory and graphical modeling.

Statement of Research Interests

Publications:

E. Ruggieri, Herbert, T., Lawrence, K.L. and C.E. Lawrence. Change Point method for detecting regime shifts in Paleoclimatic time series: Application to d180 time series of the Plio-Pleistocene.  Paleoceanography 24, PA1204, doi:10.1029/2007PA001568, 2009

Ruggieri et al 2009

E. Ruggieri and S. Schreiber. The Dynamics of the Schoener-Polt-Holis Model of Intra-Guild Predation. Math. Biosci. Eng.  2(2) 2005. 

Ruggieri and Schreiber 2005

Forthcoming :

Continual Change in the Earth’s Glaciers: An Application of the Bayesian Change Point and Variable Selection Algorithm to δ18O Time Series of the Plio-Pleistocene (in preparation)
The Mid-Pleistocene Transition: From Forcing to Pacing of Ice Sheets (in preparation)
E. Ruggieri and C.E. Lawrence, On Efficient Calculations for Bayesian Variable Selection, (to be submitted)