I am a Computer Science PhD student at the University of Massachusetts Amherst, where my research focuses on Natural Language Processing. Previously, I worked as an AI Resident at VinAI Research Vietnam and received my B.S. in Computer Science from Hanoi University of Science and Technology.

My primary research interest is enabling large language models to understand, generate, and reason about human language, so they can perform complex cognitive and language-related tasks more reliably. Recently I have been working on reinforcement learning and test-time computing, with a focus on improving the reasoning ability, factual accuracy, and efficiency of LLMs in both general and domain-specific applications.

News

  • Mar 2026Paper on tree-structured credit assignment for RL with LLMs accepted to ACL 2026 (Findings).
  • Dec 2025PRIME accepted to AAAI 2026.
  • Sep 2025LEAF accepted to EMNLP 2025 (Industry Track).
  • May 2025RARE accepted to ACL 2025.
  • 2025Awarded the Optum AI Research Fellowship.

Biography

Aug 2022 – present
PhD student, Computer Science · University of Massachusetts Amherst
May 2024 – Aug 2024
Research Intern · UII America
Nov 2019 – Jun 2022
Research Resident · VinAI Research
Jun 2018 – Oct 2019
Software Developer · VC Corporation
May 2017 – Oct 2017
AI Intern · Cinnamon AI Lab
Aug 2014 – Jun 2019
B.Eng. in Computer Science (Excellence Degree) · Hanoi University of Science and Technology

Publications

* denotes equal contribution. Click a title to view the paper. A full list is also available on my Google Scholar profile.

  1. PRIME: Planning and Retrieval-Integrated Memory for Enhanced Reasoning
    Hieu Tran, Zonghai Yao, Nguyen Luong Tran, Zhichao Yang, Feiyun Ouyang, Shuo Han, Razieh Rahimi, Hong Yu
    Proceedings of AAAI 2026 [link]
  2. Exploiting Tree Structure for Credit Assignment in RL Training of LLMs
    Hieu Tran, Zonghai Yao, Hong Yu
    Findings of ACL 2026 (arXiv:2509.18314) [link]
  3. Chatbot To Help Patients Understand Their Health
    Won Seok Jang, Hieu Tran, Manav Mistry, SaiKiran Gandluri, Yifan Zhang, Sharmin Sultana, Sunjae Kwon, Zonghai Yao, Hong Yu
    Findings of EMNLP 2025 [link]
  4. LEAF: Learning and Evaluation Augmented by Fact-Checking to Improve Factualness in Large Language Models
    Hieu Tran, Junda Wang, Yujan Ting, Hong Yu, Weijing Huang, Terrence Chen
    Proceedings of EMNLP 2025 (Industry Track) [link]
  5. RARE: Retrieval-Augmented Reasoning Enhancement for Large Language Models
    Hieu Tran, Zonghai Yao, Zhichao Yang, Junda Wang, Yifan Zhang, Shuo Han, Feiyun Ouyang, Hong Yu
    Proceedings of ACL 2025 [link]
  6. ReadCtrl: Personalizing Text Generation with Readability-Controlled Instruction Learning
    Hieu Tran, Zonghai Yao, Lingxi Li, Hong Yu
    Fourth Workshop on Intelligent and Interactive Writing Assistance, 2025 [link]
  7. Enhancing LLMs for Identifying and Prioritizing Important Medical Jargons from Electronic Health Record Notes Utilizing Data Augmentation
    Won Seok Jang, Sharmin Sultana, Zonghai Yao, Hieu Tran, Zhichao Yang, Sunjae Kwon, Hong Yu
    arXiv preprint arXiv:2502.16022, 2025 [link]
  8. ReadMe: Bridging Medical Jargon and Lay Understanding for Patient Education through Data-Centric NLP
    Zonghai Yao, Nandyala Siddharth Kantu, Guanghao Wei, Hieu Tran, Zhangqi Duan, Sunjae Kwon, Zhichao Yang, Hong Yu
    Findings of EMNLP 2024 [link]
  9. SemiHVision: Enhancing Medical Multimodal Models with a Semi-Human Annotated Dataset and Fine-Tuned Instruction Generation
    Junda Wang, Yujan Ting, Eric Z. Chen, Hieu Tran, Hong Yu, Weijing Huang, Terrence Chen
    arXiv preprint arXiv:2410.14948, 2024 [link]
  10. BioInstruct: Instruction Tuning of Large Language Models for Biomedical Natural Language Processing
    Hieu Tran, Zhichao Yang, Zonghai Yao, Hong Yu
    Journal of the American Medical Informatics Association, 31(9), 1821–1832, 2024 [link]
  11. Vietnamese Speech-Based Question Answering over Car Manuals
    Tin Duy Vo, Manh Tien Luong, Duong Minh Le, Hieu Tran, Nhan Tri Do, Duy Nguyen, Thien Hai Nguyen, Hung Hai Bui, Dat Quoc Nguyen, Dinh Phung
    Companion Proceedings of IUI 2022 [link]
  12. A Vietnamese-English Neural Machine Translation System
    Thien Hai Nguyen, Tuan-Duy H. Nguyen, Duy Phung, Duy Tran-Cong Nguyen, Hieu Minh Tran, Manh Luong, Tin Duy Vo, Hung Hai Bui, Dinh Phung, Dat Quoc Nguyen
    InterSpeech 2022 — Show & Tell [link]
  13. Learning Cross-lingual Representations for Event Coreference Resolution with Multi-view Alignment and Optimal Transport
    Duy Phung, Hieu Tran, Minh Van Nguyen, Thien Huu Nguyen
    MRL Workshop at EMNLP 2021 [link]
  14. Exploiting Document Structures and Cluster Consistencies for Event Coreference Resolution
    Hieu Tran*, Duy Phung, Thien Huu Nguyen
    Proceedings of ACL-IJCNLP 2021 (Oral) [link]
  15. The Dots Have Their Values: Exploiting the Node-Edge Connections in Graph-based Neural Models for Document-level Relation Extraction
    Hieu Tran*, Minh Trung Nguyen, Thien Huu Nguyen
    Findings of EMNLP 2020 [link]

Advisor

Awards

  • Optum AI Research Fellowship — Optum AI, 2025
  • Excellence Scholarship — Level A — School of Information and Communication Technology, HUST (awarded each semester to the top 5% of students)
  • National Excellent Student Award — Vietnam Ministry of Education and Training, 2014 (third prize, Informatics)