About

Ph.D. Student · The Chinese University of Hong Kong

I am a second-year Ph.D. student at the MoE Key Laboratory of High Confidence Software Technologies, The Chinese University of Hong Kong, supervised by Prof. Kam-Fai Wong.

My research focuses on world models, reasoning models, reinforcement learning, and multimodal learning. Before CUHK, I received my M.Eng. from Harbin Institute of Technology (Shenzhen), where I was advised by Prof. Ruifeng Xu.

News

CivWorldBench, our benchmark for evaluating language world models in Freeciv, is now available on arXiv. Explore the Project Page and code.

Our work on world model-guided reinforcement learning was accepted by EMNLP 2026 Main Conference.

I started my Ph.D. at The Chinese University of Hong Kong.

Our paper on counterfactual calibration for stance detection was accepted by NAACL 2025 Main Conference.

Our multimodal stance detection paper was accepted by ACL 2024 Findings.

Our named-entity robustness paper appeared at ICASSP 2024.

Our background knowledge-enhanced stance detection paper was accepted by EMNLP 2023 Main Conference.

Our customer-service question answering paper received the Best Paper Award at ICCC 2022.

Selected Publications

Ang Li is underlined. * denotes equal contribution.

2026
CivWorldBench overview connecting observation histories, three prediction levels, and engine evidence

CivWorldBench: Evaluating Language World Models in Structured Multi-Agent Sandbox Worlds

Ang Li, Haofei Yu, Zhengwei Tao, Liang Chen, Kuan Li, Miaomiao Li, Chenran Cai, Bin Liang, Jiaxuan You, Kam-Fai Wong

arXiv preprint · 2026

An engine-grounded benchmark in Freeciv evaluates observable forecasting, hidden-state inference, and intervention prediction, revealing gaps between forecasting strength, process correctness, and decision-making utility.

2026
A frozen user engagement world model simulates feedback and supplies rewards for policy learning

World Model-Guided Reinforcement Learning via Counterfactual User Engagement Simulation

Ang Li, Xin Xu, Bin Liang, Yue Ma, Fubang Zhao, Yangyang Kang, Kam-Fai Wong

EMNLP 2026 · Main Conference

A frozen user-engagement world model predicts counterfactual feedback and supplies dense rewards, enabling a compact 1.7B policy to match or surpass much larger LLMs without online user exposure.

2025
FACTUAL framework combining counterfactual data augmentation and a gated calibration network

Mitigating Biases of Large Language Models in Stance Detection with Counterfactual Augmented Calibration

Ang Li*, Jingqian Zhao*, Bin Liang, Lin Gui, Hui Wang, Xi Zeng, Kam-Fai Wong, Ruifeng Xu

NAACL 2025 · Main Conference

A gated calibration network trained with counterfactual augmentation corrects false-clue and target-preference biases in LLM stance reasoning.

2024
Target-aware multimodal prompt tuning architecture for text and image stance detection

Multi-modal Stance Detection: New Datasets and Model

Bin Liang*, Ang Li*, Jingqian Zhao, Lin Gui, Min Yang, Yue Yu, Kam-Fai Wong, Ruifeng Xu

ACL 2024 · Findings

Introduces five text-image stance benchmarks and a target-aware prompt-tuning framework for learning multimodal stance representations.

2024
Named entity substitution exposes prediction changes in text classifiers

Are Deep Neural Networks Robust to Named Entities? An Adversarial Attack and Defense Perspective

Hongtao Wang*, Ang Li*

ICASSP 2024

Reveals the sensitivity of text classifiers to named-entity substitution and evaluates practical augmentation-based defenses.

2023
Knowledge-augmented stance detection framework with episodic and discourse knowledge

Stance Detection on Social Media with Background Knowledge

Ang Li, Bin Liang, Jingqian Zhao, Bowen Zhang, Min Yang, Ruifeng Xu

EMNLP 2023 · Main Conference

Augments stance detection with episodic and discourse knowledge, improving both fine-tuned models and LLMs across four benchmarks.

2023
Sentence-level adversarial example generation contrasts iterative search with model inference

Efficiently Generating Sentence-Level Textual Adversarial Examples with Seq2seq Stacked Auto-Encoder

Ang Li, Fangyuan Zhang, Shuangjiao Li, Tianhua Chen, Pan Su, Hongtao Wang

Expert Systems with Applications

A nested Seq2seq auto-encoder generates fluent sentence-level adversarial examples substantially faster than word-level attacks while preserving semantics.

2022
Coarse-to-fine text matching framework for customer service question answering

A Coarse-to-Fine Text Matching Framework for Customer Service Question Answering

Ang Li*, Xingwei Liang*, Miao Zhang, Bingbing Wang, Guanrong Chen, Jun Gao, Qihui Lin, Ruifeng Xu

ICCC 2022 · Best Paper Award

A coarse-to-fine retrieval and matching pipeline improves answer accuracy while reducing inference time on customer-service datasets.

Additional Publications

2025

Knowledge-Augmented Interpretable Network for Zero-Shot Stance Detection on Social Media

B. Zhang, D. Ding, Z. Huang, A. Li, Y. Li, B. Zhang, H. Huang

IEEE Transactions on Computational Social Systems

2024

A Challenge Dataset and Effective Models for Conversational Stance Detection

F. Niu, M. Yang, A. Li, B. Zhang, X. Peng, B. Zhang

LREC-COLING 2024