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SUMMARY:Model-based sketching and recovery with expanders
DTSTART:20140219T161500
DTEND:20140219T171500
DTSTAMP:20260509T181157Z
UID:6a6da15d3d6c6a91270aa3164fcf115157a83c96397f32bd9b986946
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr. Bah BUBACARR\, EPFL\nBio: Bubacarr received a BSc in Mathe
 matics and Physics from the University of the Gambia in 2004\, and an MSc 
 in Mathematical Modeling and Scientific Computing from the University of O
 xford\, Wolfson College in 2008. He received his PhD in Applied and Comput
 ational Mathematics from the University of Edinburgh in 2012\, supervised 
 by Prof. Jared Tanner. Currently he is a postdoc with Prof. Volkan Cevher 
 at LIONS\, École Polytechnique Fédérale de Lausanne (EPFL)\, Switzerlan
 d. Previously he had been a Graduate Assistant at the University of The Ga
 mbia (2004-2007).\nLinear sketching and recovery of sparse vectors with ra
 ndomly constructed sparse matrices has numerous applications in several ar
 eas\, including compressive sensing\, data stream computing\, graph sketch
 ing\, and combinatorial group testing. This paper considers the same probl
 em with the added twist that the sparse coefficients of the unknown vector
  exhibit further correlations as determined by a known sparsity model. We 
 prove that exploiting model-based sparsity in recovery provably reduces th
 e sketch size without sacrificing recovery quality. In this context\, we p
 resent the model-expander iterative hard thresholding algorithm for recove
 ring model sparse signals from linear sketches obtained via sparse adjacen
 cy matrices of expander graphs with rigorous performance guarantees. The m
 ain computational cost of our algorithm depends on the difficulty of proje
 cting onto the model-sparse set. For the tree and group-based sparsity mod
 els we describe in this paper\, such projections can be obtained in linear
  time. Finally\, we provide numerical experiments to illustrate the theore
 tical results in action.
LOCATION:MA A3 30 http://plan.epfl.ch/?zoom=20&recenter_y=5864131.98476&re
 center_x=731135.48838&layerNodes=fonds\,batiments\,labels\,information\,pa
 rkings_publics\,arrets_metro\,transports_publics&floor=3&q=ma_a3%2030
STATUS:CONFIRMED
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