I am a researcher in machine learning and computer vision at Biometrics Research Laboratories, NEC Corporation, and a visiting researcher at RIKEN AIP. My main research interest is in the field of machine learning algorithms that work with limited supervision, such as weakly supervised learning and transfer learning.
I got my Ph. D. in physics at The University of Tokyo. The theme of my Ph. D. study was universality in strongly correlated quantum gases and few-body systems.
“Shuhei Yoshida” is such a common name that I once met a guy with the name in an physics conference! Please don’t confuse me with other “Shuhei Yoshida”. Most of my publications in English have the middle initial “M” in my name.
PhD in Science, 2018
Graduate School of Science, The University of Tokyo
MSc, 2015
Graduate School of Science, The University of Tokyo
BSc, 2013
School of Science, The University of Tokyo
This paper discusses the problem of weakly supervised classification, in which instances are given weak labels that are produced by some label-corruption process. The goal is to derive conditions under which loss functions for weak-label learning are proper and lower-bounded – two essential requirements for the losses used in class-probability estimation. To this end, we derive a representation theorem for proper losses in supervised learning, which dualizes the Savage representation. We use this theorem to characterize proper weak-label losses and find a condition for them to be lower-bounded. From these theoretical findings, we derive a novel regularization scheme called generalized logit squeezing, which makes any proper weak-label loss bounded from below, without losing properness. Furthermore, we experimentally demonstrate the effectiveness of our proposed approach, as compared to improper or unbounded losses. The results highlight the importance of properness and lower-boundedness.
«Physical Review Letters Editor’s Suggestion»
We investigate the problem of an infinitely heavy impurity interacting with a dilute
Bose gas at zero temperature. When the impurity-boson interactions are short-ranged,
we show that boson-boson interactions induce a quantum blockade effect, where a single
boson can effectively block or screen the impurity potential. Since this behavior
depends on the quantum granular nature of the Bose gas, it cannot be captured within
a standard classical-field description. Using a combination of exact quantum Monte
Carlo methods and a truncated basis approach, we show how the quantum correlations
between bosons lead to universal few-body bound states and a logarithmically slow
dependence of the polaron ground-state energy on the boson-boson scattering length.
Moreover, we expose the link between the polaron energy and the spatial structure of
the quantum correlations, spanning the infrared to ultraviolet physics.
I participated in several competitions when I was a high-school student: