Pei (Patrick) Chen

Pei (Patrick) Chen

Applied Scientist at Amazon

Amazon

Welcome!

I am an Applied Scientist at Amazon, on the LLM training and evaluation stack for customer-facing agentic systems, spanning dense and MoE architectures up to 400B+. I led two tracks: mid-training for the capability substrate — long-context and fundamental agent capability — shipped in Rufus model releases in 2024–2025; and post-training, RL, and rubric-based evaluation for model behavior — personalization, faithfulness, and multi-turn consistency — supporting releases in 2025–2026, closed by a production data flywheel that turns live-traffic failures into continuous improvement.

I obtained my Ph.D. in Computer Science from Texas A&M University, with 20+ publications (8 first-authored) at NeurIPS (Spotlight), ACL, EMNLP, and NAACL; representative first-author work includes HYTREL (NeurIPS Spotlight, set-attention for tabular LMs) and CoMM (NAACL, early multi-agent reasoning). One US patent; Area Chair at ARR.

My current research focuses on building reliable, safe, and self-evolving agentic LLMs that stay consistent over multi-turn and long-horizon interactions — through verifiable evaluation and eval-driven RL optimization.

Email: chenpei.net@gmail.com
Links: LinkedIn Google Scholar
Office: Santa Clara, CA

Interests
  • LLM Mid/Post-training (Long-context, Agentic Capability)
  • Rubric-based Evaluation & RL for Agentic Systems
  • Personalization, Memory, Multi-turn and Long-horizon Modeling
Education
  • Ph.D. in Computer Science, 2019 - 2024

    Texas A&M University

  • MS in Finance

    Southwestern University of Finance and Economics

  • B.Eng. in Simulation Engineering

    National University of Defense Technology

News

  • 2026: 3 papers on multi-turn modeling (via GRPO), personalization, and agentic systems accepted to ACL 2026. 🎉
  • 2026: Serving as Area Chair for ARR. 🎉
  • 2026: US Patent 12,530,529 granted for Domain-specific NER via Graph Neural Networks.
  • 2025: 6 papers accepted to NAACL-2025, ACL-2025, and EMNLP-2025, covering long-context modeling, agents, RAG, and post-training data flywheel. ✨
  • 2024: First-authored long paper (CoMM) accepted to NAACL-2024 — a pioneering multi-agent prompting framework for complex LLM reasoning. 👋
  • 2023: First-authored paper (HYTREL) accepted to NeurIPS-2023 as a Spotlight presentation (top 5%). ✨

Selected Publications

LLM & Foundation Model Training

Agent

RAG & Long-context & Personalization

Experience

 
 
 
 
 
Applied Scientist
Jan 2024 – Present Santa Clara, CA
Rufus foundation modeling on dense and MoE architectures up to 400B+. Led mid-training (long-context, agent capability) for Rufus model releases in 2024–2025, and post-training, RL & rubric-based evaluation (personalization, faithfulness, multi-turn consistency) for releases in 2025–2026, closed by a production data flywheel.
 
 
 
 
 
Applied Scientist Intern
Jun 2022 – Aug 2023 Santa Clara, CA
Two internship rotations — produced HYTREL (NeurIPS 2023 Spotlight) and CoMM (NAACL 2024 Findings).
 
 
 
 
 
NLP Researcher Intern
Jun 2021 – Aug 2021 Remote
Built a benchmark for zero-shot knowledge base completion (ICDM 2022 Workshop).
 
 
 
 
 
Research Engineer & Data Analyst
Chinese Academy of Sciences · State Street
Jul 2017 – Jul 2019 Beijing, China · Hangzhou, China
NLP research on financial event extraction and causality detection (CAS); data analysis and visualization for financial applications (State Street).

Misc.

🔬 By day: a creative and hands-on LLM scientist with a strong research mindset and a builder’s instinct, excited by bold new ideas in LLMs, AI assistants, and agentic systems. Enjoys exploring emerging directions and turning them into practical solutions for real-world industry problems.

💻 By night: a geek who reads papers for fun, tinkers with side projects, and has strong opinions about post-training recipes.

🥊 On weekends: 1st DAN in ITF Taekwon-Do, active in swimming, badminton, and boxing — because the best debugging happens after a good workout.