MaLGa Colloquia - Rapture of the deep: highs and lows of sparsity in a world of depths

Title

MaLGa Colloquia - Rapture of the deep: highs and lows of sparsity in a world of depths

Speaker

Rémi Gribonval - Ecole Normale Supérieure, Lyon (France)

Abstract

Promoting sparse connections in neural networks is natural to control their complexity. Besides, given its thoroughly documented role in inverse problems and variable selection, sparsity is expected to give rise to learning mechanisms endowed with performance and computational guarantees. Through an overview of recent explorations around this theme, I will compare and contrast classical sparse regularization for inverse problems with multilayer sparse regularization. During our journey, I will notably highlight the role of rescaling-invariances in deep parameterizations. In the process we will also be remembered that there is life beyond gradient descent, as illustrated by an algorithm that brings speedups of up to two orders of magnitude when learning certain fast transforms via multilayer sparse factorization.

Bio

Rémi Gribonval is a Research Director (Directeur de Recherche) with Inria and the head of the OCKHAM research group of Laboratoire de l’Informatique du Parallélisme at École Normale Supérieure de Lyon. He is the former scientific leader of the PANAMA research group on sparse audio processing at IRISA, Rennes, France. In 2011, he was awarded the Blaise Pascal Award of the GAMNI-SMAI by the French Academy of Sciences, and a starting investigator grant from the European Research Council in 2011. He is an IEEE fellow and a EURASIP Fellow. He founded the series of international workshops SPARS on Signal Processing with Adaptive/Sparse Representations. Since 2002 he has been the PI of several national (ANR, PEPR), bilateral and European (FET-Open, ERC) research projects. He was a member of the IEEE SPTM Technical Committee (2011-2017), of the EURASIP SIG-DML Special Area Team (2015-2022), and the founder and chair of the SPARS steering committee. He is on the Scientific Advisory Board of the Acoustics Research Institute of the Austrian Academy of Sciences since 2018. He was on the editorial board of EURASIP Signal Processing (2003-2006) and a Senior Area Editor for the IEEE Transactions on Signal Processing (2019-2021). He is on the editorial board of the journal Constructive Approximation since 2019 and a Senior Area Editor for the IEEE Signal Processing Magazine since 2022.

When

Monday April 28th, 16:00

Where

Room 322, UniGe DIBRIS/DIMA, Via Dodecaneso 35