Bio: Rebecca Willett is a Professor of Statistics and Computer Science at the University of Chicago. She completed her PhD in Electrical and Computer Engineering at Rice University in 2005 and was an Assistant then tenured Associate Professor of Electrical and Computer Engineering at Duke University from 2005 to 2013. She was an Associate Professor of Electrical and Computer Engineering, Harvey D. Spangler Faculty Scholar, and Fellow of the Wisconsin Institutes for Discovery at the University of Wisconsin-Madison from 2013 to 2018. Prof. Willett received the National Science Foundation CAREER Award in 2007, was a member of the DARPA Computer Science Study Group 2007-2011, and received an Air Force Office of Scientific Research Young Investigator Program award in 2010. Prof. Willett has also held visiting researcher positions at the Institute for Pure and Applied Mathematics at UCLA in 2004, the University of Wisconsin-Madison 2003-2005, the French National Institute for Research in Computer Science and Control (INRIA) in 2003, and the Applied Science Research and Development Laboratory at GE Medical Systems (now GE Healthcare) in 2002. Her research interests include network and imaging science with applications in medical imaging, wireless sensor networks, astronomy, and social networks. She is also an instructor for FEMMES (Females Excelling More in Math Engineering and Science) and a local exhibit leader for Sally Ride Festivals. She was a recipient of the National Science Foundation Graduate Research Fellowship, the Rice University Presidential Scholarship, the Society of Women Engineers Caterpillar Scholarship, and the Angier B. Duke Memorial Scholarship.
Abstract
Sparse models for machine learning have received substantial attention
over the past two decades. Model selection, or determining which
features are the best explanatory variables, is critical to the
interpretability of a learned model. Much of this work assumes that
features are only mildly correlated. However, in modern applications
ranging from functional MRI to genome-wide association studies, we
observe highly correlated features that do not exhibit key properties
(such as the restricted eigenvalue condition). In this talk, I will
describe novel methods for robust sparse linear regression in these
settings. Using side information about the strength of correlations
among features, we form a graph with edge weights corresponding to
pairwise correlations. This graph is used to define a graph total
variation regularizer that promotes similar weights for highly
correlated features. I will show how the graph structure encapsulated
by this regularizer helps precondition correlated features to yield
provably accurate estimates. The proposed approach outperforms several
previous approaches in a variety of experiments on simulated and real
fMRI data.
This is joint work with Yuan Li, Ben Mark, and Garvesh Raskutti.