Uploaded November 2024 | Updated September 2026, 2 weeks ago
Han Zhao is visiting OIST from 2024-05-26 until 2024-08-25 through the "Theoretical Sciences Visiting Program" (TSVP). Find out more about the TSVP on the program website:
oist.jp/visiting-program.
Title: Revisiting Scalarization in Multi-Task Learning
Abstract: Multi-task learning (MTL) is a paradigm that allows the model to simultaneously learn from multiple tasks for better generalization. Linear scalarization, i.e., combining all loss functions by a weighted sum, has been the default choice in the literature of MTL since its inception. In recent years, there has been a surge of interest in developing Specialized Multi-Task Optimizers (SMTOs) that treat MTL as a multi-objective optimization problem. However, it remains open whether there is a fundamental advantage of SMTOs over scalarization. In fact, heated debates exist in the community comparing these two types of algorithms, mostly from an empirical perspective. In this talk, I will first give a brief overview of MTL and its recent advances, and then revisit scalarization from a theoretical perspective. Our findings reveal that, in the linear setting, in contrast to recent works that claimed empirical advantages of scalarization, scalarization is inherently incapable of full exploration when neural networks are under-parametrized. I will also discuss two algorithmic techniques to overcome the above limitation and conclude the talk with an open question regarding the nonlinear extension of the above conclusion.
Profile: Dr. Han Zhao is an Assistant Professor of Computer Science and, by courtesy, of Electric and Computer Engineering at the University of Illinois Urbana-Champaign (UIUC). He is also an Amazon Visiting Academic at Amazon AI. Dr. Zhao earned his Ph.D. degree in machine learning from Carnegie Mellon University. His research interest is centered around trustworthy machine learning, with a focus on algorithmic fairness, robust generalization under distribution shifts and model interpretability. He has been named a Kavli Fellow of the National Academy of Sciences and has been selected for the AAAI New Faculty Highlights program. His research has been recognized through a Google Research Scholar Award, an Amazon Research Award, and a Meta Research Award.
#OIST #OIST_TSVP #MachineLearning #Theoretical #Science #VisitingProgram #Okinawa #TSVP
Han Zhao is visiting OIST from 2024-05-26 until 2024-08-25 through the "Theoretical Sciences Visiting Program" (TSVP). Find out more about the TSVP on the program website:
oist.jp/visiting-program.
Title: Revisiting Scalarization in Multi-Task Learning
Abstract: Multi-task learning (MTL) is a paradigm that allows the model to simultaneously learn from multiple tasks for better generalization. Linear scalarization, i.e., combining all loss functions by a weighted sum, has been the default choice in the literature of MTL since its inception. In recent years, there has been a surge of interest in developing Specialized Multi-Task Optimizers (SMTOs) that treat MTL as a multi-objective optimization problem. However, it remains open whether there is a fundamental advantage of SMTOs over scalarization. In fact, heated debates exist in the community comparing these two types of algorithms, mostly from an empirical perspective. In this talk, I will first give a brief overview of MTL and its recent advances, and then revisit scalarization from a theoretical perspective. Our findings reveal that, in the linear setting, in contrast to recent works that claimed empirical advantages of scalarization, scalarization is inherently incapable of full exploration when neural networks are under-parametrized. I will also discuss two algorithmic techniques to overcome the above limitation and conclude the talk with an open question regarding the nonlinear extension of the above conclusion.
Profile: Dr. Han Zhao is an Assistant Professor of Computer Science and, by courtesy, of Electric and Computer Engineering at the University of Illinois Urbana-Champaign (UIUC). He is also an Amazon Visiting Academic at Amazon AI. Dr. Zhao earned his Ph.D. degree in machine learning from Carnegie Mellon University. His research interest is centered around trustworthy machine learning, with a focus on algorithmic fairness, robust generalization under distribution shifts and model interpretability. He has been named a Kavli Fellow of the National Academy of Sciences and has been selected for the AAAI New Faculty Highlights program. His research has been recognized through a Google Research Scholar Award, an Amazon Research Award, and a Meta Research Award.
#OIST #OIST_TSVP #MachineLearning #Theoretical #Science #VisitingProgram #Okinawa #TSVP








![Panayotis Kevrekidis: Nonlinear Waves and their Applications (TSVP Talk at OIST)
Title: Nonlinear Waves and Their Applications: From Oceans to Planets, From Lasers to Quantum Fluids, From Origami to Pandemics
Speaker: Panayotis Kevrekidis, Distinguished University Professor, University of Massachusetts, Amherst
Abstract: In this talk, I will explore a number of ideas about nonlinear waves and their implications to a diverse array of fields: from mathematics to physics, engineering, computing, biology, and even (a little) art. I will begin with some history from 18th and 19th century fluid waves in channels and oceans, associated engineering observations, and artistic renderings. Next, I will share an intriguing story of (non) equity and inclusion around the first computer in post-atomic-bomb Los Alamos National Lab. The presentation will then pass through some Nobel Prize winning physical ideas related to the laser, quantum fluids, and some of their recent variations pursued experimentally including at Amherst. Finally, we will touch upon how in the past few years such wave phenomena have emerged in exotic materials, such as lattices made of origami elements, and how they have been leveraged toward studying the spread of pandemic infections.
Profile: Professor Kevrekidis studies a variety of systems stemming from the mathematical physics of nonlinear optical systems, of crystalline materials, as well as from the ultracold atomic setting of Bose-Einstein Condensates. The research mainly revolves around the existence, stability and dynamics of localized (solitary wave) structures in such one-, two- and three-dimensional setups, often described by equations of Nonlinear Schrodinger or Klein-Gordon type. Besides this main thrust of research Professor Kevrekidis also maintains a wide variety of additional modeling interests including mathematical biology [especially tumor angiogenesis, nephron dynamics and DNA models], simple cosmological models, the nucleation of liquid droplets, phase transition phenomena, catalytic chemistry and associated reaction-diffusion models, and dynamics and energy landscapes of glassy materials among others.
Kevrekidis is a Fellow of the American Physical Society (APS), of the American Mathematical Society (AMS) and of the Society for Industrial and Applied Mathematics (SIAM). He has been awarded an Honorary Doctorate from the University of Ioannina, Greece (2023), and has been elected in 2024 as a member of the European Academy for Sciences and the Arts (EASA).
Find out more about the TSVP on the program website: https://www.oist.jp/visiting-program
#OIST #OIST_TSVP #NonlinearOpticalSystems #mathematics #physics #research #oist #oist_tsvp #Theoretical #Science #VisitingProgram #Okinawa #TSVP Panayotis Kevrekidis: Nonlinear Waves and their Applications (TSVP Talk at OIST)](https://i.ytimg.com/vi/PI5uHRArr10/mqdefault.jpg)

