CV
Curriculum vitae.
Contact Information
| Name | Zaiyi Zheng |
| Professional Title | Ph.D. Student |
| sjc4fq@virginia.edu | |
| Website | https://zhengzaiyi.github.io |
Summary
Ph.D. student in Computer Engineering at the University of Virginia, advised by Professor Jundong Li. My research interests lie in recommendation systems, retrieval-augmented generation, and large language models.
Education
-
2023 - present Charlottesville, VA, United States
-
2018 - 2022 Hefei, Anhui, China
B.E.
University of Science and Technology of China
Computer Science
Industry Experience
-
2026 - 2027 Bellevue, WA, United States
Research Advisor II
Meta
Topic: LLM for Recommendation. Adviser: Dr. Cassie Dong.
- Built a large-scale transformer-based model for effective and efficient ads ranking.
-
2026 - 2026 Sunnyvale, CA, United States
Machine Learning Research Intern
Nokia America
Topic: Generative Recommendation. Adviser: Dr. Liang Wu.
- Studied semantic ID (SID) based generative recommendation with large language models, focusing on reasoning-aware generation and efficient inference.
- Constructed explicit Chain-of-Thought (CoT) reasoning traces for each meta token in SID generation and trained a teacher model with a two-stage SFT-then-RL pipeline.
- Introduced auxiliary soft-thinking tokens for approximately 1B-parameter student models and distilled the teacher’s CoT into continuous latent embeddings.
- Deployed only the student model at inference time, achieving comparable ranking quality to explicit CoT-based generation with reduced latency and generation cost.
-
2025 - 2025 Bellevue, WA, United States
Machine Learning Research Intern
Snap Inc.
Topic: Agentic Recommendation Systems. Adviser: Dr. Clark Ju.
- Developed a personalized LLM-based agent for multi-channel item recall by extending Hugging Face’s TRL framework.
- Designed and implemented a soft-token mechanism to structurally generate routing weights over recall channels.
- Modified the vLLM inference engine to support high-throughput soft-token decoding and agent-style online interaction.
- Adapted Group Relative Policy Optimization (GRPO) to optimize adaptive routing over multiple recall models.
-
2024 - 2025 Bellevue, WA, United States
Research Assistant
Snap Inc.
Topic: Cold-Start Item Recommendation. Adviser: Dr. Neil Shah.
- Developed an adaptive cold-start item recommendation system for rapidly emerging items with sparse or zero interaction histories.
- Proposed MI4Rec, a PLM-based cold-start recommender that infers item representations via meta-item embedding composition.
- Evaluated on Amazon-Beauty, Toys, Sports, and Yelp under cold-start, warm-start, and general settings, achieving up to 15.71% relative improvement in Recall.
-
2022 - 2022 Hangzhou, Zhejiang, China
Machine Learning Engineer Intern
Zerozero Robotics
Topic: Trajectory Planning. Adviser: Hao Zhang.
- Built an outdoor trajectory planning system for physical quadrotors and constructed realistic evaluation environments in Unity.
- Reproduced an imitation learning framework and incorporated data aggregation to improve obstacle avoidance.
- Achieved an 18.2% relative reduction in navigation failure rate in outdoor environments.
Academic Experience
-
2023 - present Charlottesville, VA, United States
Research Assistant
University of Virginia
Topic: Retrieval-Augmented Generation (RAG). Adviser: Prof. Jundong Li.
- Proposed CoRAG, a hybrid RAG framework that dynamically selects between global textual retrieval and graph-based relational retrieval.
- Designed a Cooperative-Retrievers (CoR) mixture-of-retrievers module with hierarchical gating to adaptively fuse heterogeneous retrieval signals.
- Demonstrated strong performance on STaRK semi-structured KGQA benchmarks, achieving up to 11.4% relative Hit@1 improvement over prior RAG baselines.
-
2021 - 2021 Austin, TX, United States
Research Assistant
University of Texas at Austin
Topic: Indoor Navigation. Adviser: Dr. Wuyang Chen.
- Developed an efficient and transferable robot navigation method for sim-to-real deployment.
- Implemented a PPO-based navigation pipeline on Meta’s Habitat platform.
- Proposed a contrastive learning component for visual representation learning with positive and negative sampling.
Interests
Skills
Awards
-
2025 Student Travel Award
CIKM 2025 and BigData 2024.
-
2019 Silver Scholarship for Outstanding Students
University of Science and Technology of China, 2019 - 2022.
-
2019 Talents Class Scholarship
University of Science and Technology of China.