Upcoming seminar: Urbashi Mitra
Title: Unimodal factorization for multi-source & multimodal target localization
When: Friday, 27 September 2019, 11:00 – 12:00
Where: Room 206, UCD Engineering and Materials Science Centre
Abstract: We consider matrix and tensor factorization problems where there are both unimodal and rank constraints. These strategies are employed to find 'peaky' signals in observational data. Peak finding has application in a variety of problems such as target localization, environmental monitoring, epidemic detection, and medical diagnosis. We presume that we have incomplete (sparse) and noisy samples of a particular field or image and that our objects of interest have spatial extent and can be modeled as approximately low rank and unimodal: for one source, there is a single, strong signal peak and this signal decays as one moves away from the target. By exploiting modern signal processing techniques such as matrix completion and active search methods, we develop a high performance, moderate complexity algorithm for peak detection. This method is extended to the case of multiple targets via novel matrix factorization and isotonic projection methods. We further extend the approach to handle multimodal sensor data by exploiting tensor completion methods. Even lower complexity, projection-free algorithms are provided to approximately solve the unimodal matrix factorization and shown to provide near optimal performance. The proposed methods strongly outperform a state-of-the-art kernel-regression method.
Bio: Urbashi Mitra received the B.S. and the M.S. degrees from the University of California at Berkeley and her Ph.D. from Princeton University. Dr. Mitra is currently the Gordon S. Marshall Professor in Engineering at the University of Southern California with appointments in Electrical & Computer Engineering and Computer Science. She was the inaugural Editor-in-Chief for the IEEE Transactions on Molecular, Biological and Multi-scale Communications. She has been a member of the IEEE Information Theory Society's Board of Governors (2002-2007, 2012-2017), the IEEE Signal Processing Society's Technical Committee on Signal Processing for Communications and Networks (2012-2016), the IEEE Signal Processing Society's Awards Board (2017-2018), the Vice Chair of the IEEE Communications Society, Communication Theory Technical Committee (2017-2018) and now the Chair. Dr. Mitra is a Fellow of the IEEE. Her research interests are in wireless communications, communication and sensor networks, biological communication systems, detection and estimation & the interface of communication, sensing and control.