Xiaoyi (Alleria) Gu

Xiaoyi (Alleria) Gu

Applied Scientist at Twitch (Amazon)         


About Me

I am an Applied Scientist on Twitch’s Community Discovery team, designing end-to-end ML systems and optimizing large-scale live-stream ranking models serving millions of users. My work centers on segment-aware multi-objective ranking and search recommendations.

Before entering industry, I earned my M.S. in Applied Data Science from the University of Southern California.

I am particularly interested in:

  • Multi-objective learning in recommender systems
  • Personalization & search systems
  • LLM-assisted ranking and retrieval
  • RAG systems and agents

Professional Experience

Twitch (Amazon) — Applied Scientist (Sep 2024 – Present)

  • Lead large-scale multi-objective optimization for live-stream recommendation systems, defining engagement and retention trade-offs in production.
  • Design and scale segment-aware multi-model architectures (MTL, MMoE, curriculum learning) to support diverse user behaviors.
  • Build end-to-end ML ranking pipelines, addressing data quality improvements, model training, offline evaluation, and online A/B experimentation.
  • Partner cross-functionally with engineering and data science to clarify problem definitions and deliver measurable metric improvements.

SylphAI — Machine Learning Engineer (Apr 2024 – Aug 2024)

  • Built RAG and ReAct agent based chatbot search engine
  • Contributed to open-source LLM framework (AdalFlow)

Selected Research

Survey thumbnail
Video Generation Models: A Survey of Post-Training and Alignment
..., Xiaoyi Gu, ...
Under review at TMLR (2026)