Big Data Chalk & Talk/Brown Bag

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December 5, 2013 12:00 pm - 1:30 pm
MiRC 102 A&B

Four Georgia Tech research hubs have launched a new “chalk & talk” brown bag lunch series on Big Data. The weekly series, sponsored jointly by the Institute for Data & High Performance Computing (IDH), Institute for Materials (IMaT)Center for Data Analytics (CDA) and Center for High Performance Computing (HPC) will be held on most Thursdays during the Fall and Spring Semesters and feature a mix of topics, including those related to big data for materials and manufacturing, as well as other topics critical to the broader area of big data.

All meetings are held on Thursdays during lunchtime. 

Date: December 5
Topic: “Using Structure to Solve Underdetermined Systems of linear Equations and Over-determined Systems of Quadratic Equations”
Presenters(s): Justin Romberg


We will start by giving a high-level overview of the fundamental results in the field that has come to be known as compressive sensing. The central theme of this body of work is that underdetermined systems of linear equations can be meaningfully “inverted” if they have structured solutions. Two examples of structure would be if the unknown entity is a vector, which is sparse (has only a few “active” entries), or if it is a matrix, which is low rank. We discuss some of the applications of this theory in signal processing and machine learning.

In the second part of the talk, we will show how some of these structured recovery results give us new insights into solving systems of quadratic and bilinear equations. In particular, we will show how recasting classical problems like channel separation and blind deconvolution as a structured matrix factorization gives us new insight into how to solve them.


Justin Romberg is an associate professor in the School of Electrical and Computer Engineering. He received B.S.E.E. (1997), M.S. (1999) and Ph.D. (2004) degrees from Rice University in Houston, Texas. From Fall 2003 until Fall 2006, he was a postdoctoral scholar in Applied and Computational Mathematics at the California Institute of Technology. In the fall of 2006, Romberg joined the ECE faculty at Georgia Tech. In 2009, he received a PECASE award and a Packard Fellowship, and in 2010, he was named a Rice University Outstanding Young Engineering Alumnus. Romberg is currently on the editorial board for the SIAM Journal on Imaging Science.