April 8, 2022  – The Mezić Group is pleased to host Mario Sznaier from Northeastern University, USA

Mario Sznaier from Northeastern University, USA will give a Zoom seminar on Friday, April 8, 2022 at 9AM PST.

Title: A Convex Optimization Approach to Learning Koopman Operators from Data

Abstract: Koopman operators provide tractable means of learning linear approximations of  non-linear dynamics. Many approaches have been proposed to find these operators,  typically  based upon approximations using an a-priori fixed class of models. However, choosing appropriate models and bounding the approximation error is far from trivial.  Motivated by these difficulties, in this talk we propose  an optimization based approach to  learning  Koopman operators from data. Our results show that the Koopman operator, the associated Hilbert space of observables and a suitable dictionary can be obtained by solving two rank-constrained semi-definite programs (SDP). While in principle these problems are NP-hard, the use of standard relaxations of rank leads to  convex SDPs.  In the second portion of the talk we will briefly discuss some new architectures motivated by Koopman operator theory. . However, as shown with a simple example, these results cannot be extended to actuated models. The talk will conclude by exploring the connection between LPV identification, bilinear identification and actuated Koopman models.

Short Bio: Mario Sznaier is currently the Dennis Picard Chaired Professor at the Electrical and Computer Engineering Department, Northeastern University, Boston. Prior to joining Northeastern University, Dr. Sznaier was a Professor of Electrical Engineering at the Pennsylvania State University and also held visiting positions at the California Institute of Technology. His research interest include robust identification and control of hybrid systems, robust optimization, and dynamical vision. Dr. Sznaier is currently serving as chair of the IFAC Technical Committee on Robust Control and Founding Editor in Chief of the section on AI and Control of the Journal Frontiers in Control. Engineering . Past recent service include Associate Editor for Automatica (2005-2021), Program Chair of the 2017 IEEE Conf. on Decision and Control, General Chair of the 2016 IEEE Multi Systems Conference, Chair of the  IEEE Control Systems Society Technical Committee on Computational Aspects of Control Systems Design (2013-2017),  He is a distinguished member of the IEEE Control Systems Society  and a Fellow of the IEEE for his contributions to robust control, identification and dynamic vision. A list of publications and current research projects can be found at http://robustsystems.coe.neu.edu.