Timothy Sweetser

Experience

StubHub, New York, NY

Machine Learning Engineer. April 2024 - Present

Recommendations and personalization in Python and C#

Improve website recommendations through innovations in candidate generation and model architecture GRU4Rec

Warner Brothers Discovery, New York, NY

Machine Learning Engineer. November 2020 - March 2024

Reponsible for scaling and innovation of recommender systems and personalization for Max and HBO Max

Scale personalization algorithms to tens of millions of users using Airflow, Docker, and Spark

Increase user engagement of personalized recommendations tray using EASE model and XGBoost ensemble

Move from offline to online scoring using custom Tensorflow Serving implementation

FindMine, New York, NY

Machine Learning Engineer. May 2019 - November 2020

Increase click through rate by 3% using $\epsilon$-greedy bandit

Use deep learning to identify similar styles based on images

Reduce costs by $50K/year by automatically replacing out of stock items in expert-curated fashion outfits

Save $60K/year in cloud computing costs by shifting computation from database to Python layer

Write a Flask app to collect quantitative fashion ratings from subject matter experts

Rent the Runway, New York, NY

Data Scientist | August 2018 - April 2019

Develop fit algorithm to boost rental wear rate by +0.01
Increase user engagement by improving personalized recommendations
Rewrite production recommendation service using asyncio, an asynchronous Python web framework
Migrate batch model training from laptops to Jenkins

Stitch Fix, San Francisco, CA

Data Scientist | July 2015 - June 2018

Increased revenue by $8+ million per year by quantifying style
Use contextual bandits to optimize where and when to show different recommendations
Develop end-to-end data science pipelines in Spark, Python and R using AWS, Docker, and Jenkins

Timothy D. Sweetser