Self-Supervised Representation Learning for Motion Time Series: A Case Study in Activity Recognition
Copyright 2023 Luis Carlos Garza Perez. All Rights Reserved.
In this thesis we will learn about what contrastive learning and time series are and understand the differences between supervised and self-supervised frameworks in machine learning. In addition, we will describe how the newest and most efficient self-supervised learning framework for visual representations to this date works, called SimCLR, which was originally developed to obtain useful vector representations from static images. We will also explain what TS2Vec is, and how a combination of both approaches can be applied to the concept of a time series, and still be able to extract a vector representation of the subject described by the time series, our goal is to show that even when the input dataset does not contain visual representations, contrastive learning can still be applied successfully, including when the whole subject data is spread between multiple time series.