LIU Jiayu

LIU Jiayu

He/him

Year 3 Computer Science Undergraduate at HKUST

Jiayu LIU 刘家毓

👋 Welcome to my homepage! 🥂
I’m Jiayu LIU 刘家毓, a junior undergraduate CS student at HKUST. I am currently a exchange student in UIUC and an undergraduate research intern at BLENDER lab advised by Prof. Ji Heng. Previously, I was supervised by Prof. Yangqiu Song and Prof. Yiren Fung at HKUST.

My research goal is to build LLM/agents which is both robust and creative.

My current research focuses on:

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Advanced tool-use capabilities in agentic systems

Building high-performing, cost-effective agents

  1. Study tool use robustness in dynamic environments through systematic benchmarking [CostBench]
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Evaluating and enhancing LLM reasoning capabilities

Pinpointing the crucial flaws in LLM reasoning and training diverse-thinking reasoning models

  1. Identify failure reasons (mathematical proof reasoning [RFMBench], RLIF [Rethinking RLIF])
  2. Self-evolution with verificable signals (Diversity-Enhanced Reasoning with RL [Multirole-R1], Self-evolution via code [Code2Math])
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Improving LLM trustworthiness

Analyzing LLM confidence elicitation patterns and training well-calibrated LLMs, especially in knowledge enhanced scenarios

  1. Investigate LLM confidence expression reliability through epistemic markers [MarConf] and decision-making stability under uncertainty [MarPT]
  2. Improve LLM Calibration Performance (in RAG systems [NAACL], via Critique [CritiCAL])

Here is my google Scholar 📫 Contact: jliufv@connect.ust.hk

🔥 News

- [2026/1] My co-first-author paper Diversity-Enhanced Reasoning for Subjective Questions is accepted by ICLR 2026!
- [2026/1] Released NAACL: Noise-AwAre Verbal Confidence Calibration for LLMs in RAG Systems, which got 30 upvotes and ranked #3 in Hugging Face Daily Papers (January 20th)!
- [2025/12] Honored to join UIUC BLENDER Lab as a undergraduate research intern! Looking forward to learning from Prof. Heng Ji!
- [2025/11] Released CostBench: Evaluating Multi-Turn Cost-Optimal Planning and Adaptation in Dynamic Environments for LLM Tool-Use Agents, which got 21 upvotes and ranked #4 in Hugging Face Daily Papers (November 6th)!
- [2025/8] Honored to receive the UROP Support Grant and UROP Research Travel Sponsorship!
- [2025/7] Released Diversity-Enhanced Subjective Question-Answering, which got 26 upvotes and ranked #8 in Hugging Face Daily Papers (July 29th)!
- [2025/7] Will join University of Illinois Urbana-Champaign as an exchange undergraduate student in Spring 2026!
- [2025/5] My first-author paper Revisiting Epistemic Markers in Confidence Estimation is accepted to ACL 2025 Main! Sincere gratitude to all my collaborators!
- [2025/2] Honored to join HKUST RenAI Lab as a undergraduate research intern! Looking forward to learning from Prof. Yiren Fung!
- [2025/1] Honored to receive HKIE Scholarship 2024/25!
- [2024/10] My co-first-author paper GProofT is accepted by The Seventh FEVER Workshop!
- [2024/9] Honored to receive The Joseph Lau Luen Hung Charitable Trust Scholarship 2024/25!
- [2024/6] Traveled to Charles University in Prague for summer exchange! Wonderful experience — loved everything there 🥰
- [2024/6] Honored to join HKUST KnowComp Group as a undergraduate research intern! Looking forward to learning from Prof. Yangqiu Song!
- [2023/9] Honored to receive China Soong Ching Ling Foundation Zhiyuan Bursary!

📖 Selected Publications

Note: Only first author/co-first author papers are listed. Please refer to the publications page for full publications. * denotes equal contribution.

Diversity-Enhanced Reasoning
ICLR 2026
Diversity-Enhanced Reasoning for Subjective Questions
Yumeng Wang*, Zhiyuan Fan*, Jiayu Liu*, Jen-tse Huang, Yi R. Fung
arxiv HF Daily Papers code
Revisiting Epistemic Markers
ACL 2025
Revisiting Epistemic Markers in Confidence Estimation: Can Markers Accurately Reflect Large Language Models' Uncertainty?
Jiayu Liu, Qing Zong, Weiqi Wang, Yangqiu Song
ACL anthology arxiv code
NAACL
Under Review
NAACL: Noise-AwAre Verbal Confidence Calibration for LLMs in RAG Systems
Jiayu Liu*, Rui Wang*, Qing Zong, Qingcheng Zeng, Tianshi Zheng, Haochen Shi, Dadi Guo, Baixuan Xu, Chunyang Li, Yangqiu Song
arxiv HF Daily Papers code
CostBench
Under Review
CostBench: Evaluating Multi-Turn Cost-Optimal Planning and Adaptation in Dynamic Environments for LLM Tool-Use Agents
Jiayu Liu, Cheng Qian, Zhaochen Su, Qing Zong, Shijue Huang, Bingxiang He, Yi R. Fung
arxiv HF Daily Papers code
Prospect Theory Fails
Under Review
Prospect Theory Fails for LLMs: Revealing Instability of Decision-Making under Epistemic Uncertainty
Rui Wang*, Qihan Lin*, Jiayu Liu*, Qing Zong, Tianshi Zheng, Weiqi Wang, Yangqiu Song
arxiv code
Mathematical Proof as a Litmus Test
MathNLP 2025
Mathematical Proof as a Litmus Test: Revealing Failure Modes of Advanced Large Reasoning Models
Dadi Guo*, Jiayu Liu*, Zhiyuan Fan, Zhitao He, Haoran Li, Yumeng Wang, Yi R. Fung
arxiv code
GProofT
FEVER 2024
GProofT: A Multi-dimension Multi-round Fact Checking Framework Based on Claim Fact Extraction
Jiayu Liu*, Junhao Tang*, Hanwen Wang*, Baixuan Xu, Haochen Shi, Weiqi Wang, Yangqiu Song
ACL anthology code

🧾 Academic & community services

  • [2025/6] HKUST COMP and CPEG Mentor 2024/25
  • [2025/5] Reviewer of IJCAI 2025
  • [2024/6] HKUST PMP group mentor
  • [2024/2] IT Secretary of Chinese Folks and Arts Society, HKUST

Misc

In my spare time, I’m passionate about music and sports. I play the piano and violin, and I also enjoy singing and sharing my performances on social media. For sports, football is my absolute favorite—I’m a member of both the HKUST Mainland Students Football Team and the Guangdong Experimental High School Football Team, and I truly cherish the memories and friendships from those times. I also enjoying sailing in the sea, and yatching makes me feel an incredible sense of freedom.

Feel free to check out some of my music:

  • Me playing Chopin’s Fantaisie-Impromptu: Youtube
  • Me performing the Chinese ballad Why Are the Flowers So Red: Youtube
  • My singing profile: WeSing (全民k歌) (~200 fans)