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From YouTube: 2021-01-19 - Md Abul Hayat & George Stein - Self-Supervised Representation Learning for Astro Images

Description

NERSC Data Seminars Series: https://github.com/NERSC/data-seminars

Title: Self-Supervised Representation Learning for Astronomical Images

Speakers: Md Abul Hayat (University of Arkansas, Berkeley Lab), George Stein (UCB, Berkeley Lab)

Abstract: Sky surveys are the largest data generators in astronomy, making automated tools for extracting meaningful scientific information an absolute necessity. We show that, without the need for labels, self-supervised learning recovers representations of sky survey images that are semantically useful for a variety of scientific tasks. These representations can be directly used as features, or fine-tuned, to outperform supervised methods trained only on labeled data. We apply a contrastive learning framework on multi-band galaxy photometry from the Sloan Digital Sky Survey (SDSS), to learn image representations. We then use them for galaxy morphology classification, and fine-tune them for photometric redshift estimation, using labels from the Galaxy Zoo 2 dataset and SDSS spectroscopy. In both downstream tasks, using the same learned representations, we outperform the supervised state- of-the-art results, and we show that our approach can achieve the accuracy of supervised models while using 2-4 times fewer labels for training.

Bios:
Md Abul Hayat is a 4th year PhD student of Electrical engineering at the University of Arkansas. His research is on predicting hydration status using signal processing and statistical learning techniques from biomedical signals. In past years he has worked at Berkeley Lab and Nokia Bell Labs as a summer intern. Before joining the PhD program, he has worked as a telecommunications system engineer at Telenor Bangladesh.

George Stein is a postdoc at LBL/BCCP, with research centered on machine learning for cosmology. Areas of focus include cosmological simulations, generative models, anomaly detection, and of course self-supervised learning.