About Me
I am currently a senior researcher at Meituan, leading an effort on application and research of GenAI and foundation models. Previously, I worked as a senior researcher at Huawei and a researcher at Sensetime Research.
I obtained my Ph.D. degree from University of Science & Technology of China (USTC). During my graduate study, I spent a wonderful time at Multimedia Lab (MMLab), Chinese University of Hong Kong, under the supervision of Prof. Xiaogang Wang.
My research interests focus on multimodal & foundation models, Agentic Learning and AIGC, as well as their applications in industry.
** Positions are available for highly self-motivated full-time researchers, engineers and interns!
** Looking for long-term collaborations on research in the fields of Agent, foundation models and GenAI!
News
- ** Looking for long-term collaborations on research in the fields of foundation models, Agent, RL and GenAI!
- ** Positions are available for highly self-motivated full-time researchers, engineers and interns!
- [2026/05] We release three papers on RL for LLM training: Joint Training MTP, ZipRL, and When Self-Belief Misleads.
- [2026/05] We release the token-level credit assignment method AMR-SD.
- [2026/05] We release the tool-integrated reasoning method Implicit Hierarchical GRPO.
- [2026/05] Two papers (CDRRM and LocalSearchBench) are accepted to KDD 2026.
- [2026/05] Recognized as Gold Reviewer for ICML 2026.
- [2026/05] We release the benchmark for reward modeling RecRM-Bench.
- [2026/05] New homepage launched.
- [2026/05] Six papers are accepted to ICML 2026.
- [2026/04] We release the self-distillation for deep search π-Play.
- [2026/04] Three papers are accepted to ACL 2026 (One Main and two findings).
- [2026/01] We release our discovery on advantage estimation Your Group-Relative Advantage Is Biased.
- [2026/01] Seven papers are accepted to ICLR 2026 (Six mains and one workshop).
- [2025/12] We release Local Search Benchmark for agentic search LocalSearchBench.
- [2025/11] Our paper for Verifiable Stepwise Reward is accepted to AAAI 2026.
- [2025/08] Three papers are accepted to EMNLP 2025 (Two mains and one findings).
- [2025/06] Our Agentic RL framework RL Factory is released!
Publications
* Equal contribution # Corresponding author
Preprints & Under Review
RLFactory: A Plug-and-Play Reinforcement Learning Post-Training Framework for LLM Multi-Turn Tool-Use
Jiajun Chai*, Guojun Yin*, Chengqi Dong, Hang He, Yi Jia, Jiwen Jiang, Xiaoguang Li, Xiaohan Wang, Siyu Xia, Zekun Xu, Chuhuai Yue, Wei Lin
RecRM-Bench: Benchmarking Multidimensional Reward Modeling for Agentic Recommender Systems
Wenwen Zeng*, Jinhui Zhang*, Hao Chen*, Zhaoyu Hu, Yongqi Liang, Jiajun Chai, Dengcan Liu, Zhenfeng Liu, Shurui Yan, Minglong Xue, Xiaohan Wang, Wei Lin, Guojun Yin#
Joint Training of Multi-Token Prediction in Reinforcement Learning via Optimal Coefficient Calibration
Zili Wang*, Jiajun Chai, Lin Chen, Xiaohan Wang, Shiming Xiang, Guojun Yin
ZipRL: Adaptive Multi-Turn Context Compression with Hindsight Response Replay
Zhexin Hu, Li Wang, Xiaohan Wang, Jiajun Chai, Xiaojun Guo, Wei Lin, Xin Zhou, Guojun Yin
When Self-Belief Misleads: Active Label Acquisition for Reinforcement Learning with Verifiable Rewards
Li Wang*, Xiaodong Lu*, Xiaohan Wang, Yikun Ban, Jiajun Chai, Wei Lin, Tianhao Peng, Guojun Yin#
AMR-SD: Asymmetric Meta-Reflective Self-Distillation for Token-Level Credit Assignment
Zhenlin Wei*, Pu Jian*, Yingzhuo Deng*, Xiaohan Wang, Jiajun Chai, Zhexin Hu, Wei Lin, Shanbin Zhang, Guojun Yin
Implicit Hierarchical GRPO: Decoupling Tool Invocation from Execution for Tool-Integrated Mathematical Reasoning
Li Wang*, Xiaohan Wang*, Xiaodong Lu, Zipeng Zhang, Jinyang Wu, Jiajun Chai, Wei Lin, Guojun Yin#
π-Play: Multi-Agent Self-Play via Privileged Self-Distillation without External Data
Yaocheng Zhang*, Yuanheng Zhu*, Wenyue Chong, Songjun Tu, Qichao Zhang, Jiajun Chai, Xiaohan Wang, Wei Lin, Guojun Yin, Dongbin Zhao
Your Group-Relative Advantage Is Biased
Fengkai Yang, Zherui Chen, Xiaohan Wang, Xiaodong Lu, Jiajun Chai, Guojun Yin, Wei Lin, Shuai Ma, Fuzhen Zhuang, Deqing Wang, Yaodong Yang, Jianxin Li, Yikun Ban
AWPO: Enhancing Tool-Use of Large Language Models through Adaptive Integration of Reasoning Rewards
Zihan Lin*, Xiaohan Wang*, Hexiong Yang, Jiajun Chai, Jie Cao, Guojun Yin#, Wei Lin, Ran He
ToolForge: A Data Synthesis Pipeline for Multi-Hop Search without Real-World APIs
Hao Chen, Zihao Hu, Jiajun Chai, Hexiong Yang, Hang He, Xiaohan Wang, Wei Lin, Lei Wang, Guojun Yin#
IMAgent: Training Multi-Image Vision Agents via End2End Reinforcement Learning
Chengqi Dong, Chuhuai Yue, Hang He, Rongge Mao, Fenghe Tang, S Kevin Zhou, Zekun Xu, Xiaohan Wang, Jiajun Chai, Guojun Yin#
From Experience to Strategy: Empowering LLM Agents with Trainable Graph Memory
Siyu Xia*, Zekun Xu*, Jiajun Chai, Wentian Fan, Yan Song, Xiaohan Wang, Guojun Yin, Wei Lin, Haifeng Zhang, Jun Wang
Tagging the Thought: Unlocking Personalization Reasoning via Reinforcement Learning
Song Jin*, Juntian Zhang, Yong Liu, Xun Zhang, Yufei Zhang, Fei Jiang, Guojun Yin, Wei Lin, Rui Yan
Published Papers
LocalSearchBench: Benchmarking Agentic Search in Real-World Local Life Services
Hang He, Chuhuai Yue, Chengqi Dong, Mingxue Tian, Hao Chen, Zhenfeng Liu, Jiajun Chai*, Xiaohan Wang, Yufei Zhang, Qun Liao, Guojun Yin#, Wei Lin, Chengcheng Wan, Haiying Sun, Ting Su
CDRRM: Contrast-Driven Rubric Generation for Reliable and Interpretable Reward Modeling
Dengcan Liu*, Fengkai Yang*, Xiaohan Wang, Shuai Yan, Jiajun Chai, Jianxin Li, Yikun Ban, Zhichao Mao, Wei Lin, Guojun Yin#
SSL4RL: Revisiting Self-supervised Learning as Intrinsic Reward for Visual-Language Reasoning
Xiaojun Guo*, Runyu Zhou*, Yifei Wang, Qi Zhang, Chenheng Zhang, Stefanie Jegelka, Xiaohan Wang, Jiajun Chai, Guojun Yin, Wei Lin, Yisen Wang
ResRL: Boosting LLM Reasoning via Negative Sample Projection Residual Reinforcement Learning
Zihan Lin*, Xiaohan Wang*, Jie Cao, Jiajun Chai, Li Wang, Xiaodong Lu, Wei Lin, Ran He, Guojun Yin#
GRASP: Graph Reasoning via Agentic Solving and Probing of LLMs
Xiaojun Guo*, Mingxue Tian*, Chenheng Zhang, Xiaohan Wang, Jiajun Chai, Guojun Yin, Wei Lin, Yifei Wang, Yisen Wang
Contextual Rollout Bandits for Reinforcement Learning with Verifiable Rewards
Xiaodong Lu, Xiaohan Wang, Jiajun Chai, Guojun Yin, Wei Lin, Zhijun Chen, Yu Luo, Fuzhen Zhuang, Yikun Ban, Deqing Wang
Rethinking Personalization in Large Language Models at the Token Level
Chenheng Zhang, Yijun Lu, Lizhe Fang, Chunyuan Zheng, Jiajun Chai, Xiaohan Wang, Guojun Yin, Wei Lin, Yisen Wang, Zhouchen Lin
AgentConductor: Topology Evolution for Multi-Agent Competition-Level Code Generation
Siyu Wang, Ruotian Lu, Zhihao Yang, Yuchao Wang, Yanzhou Zhang, Lei Xu, Qimin Xu, Guojun Yin, Cailian Chen, Xinping Guan
DiningBench: A Hierarchical Multi-view Benchmark for Perception and Reasoning in the Dietary Domain
Song Jin*, Juntian Zhang*, Xun Zhang, Zeying Tian, Fei Jiang, Guojun Yin, Wei Lin, Yong Liu, Rui Yan
Beyond Dialogue Time: Temporal Semantic Memory for Personalized LLM Agents
Miao Su, Yucan Guo, Zhongni Hou, Long Bai, Zixuan Li, Yufei Zhang, Guojun Yin, Wei Lin, Xiaolong Jin, Jiafeng Guo, Xueqi Cheng
AutoSearch: Adaptive Search Depth for Efficient Agentic RAG via Reinforcement Learning
Jingbo Sun*, Wenyue Chong*, Songjun Tu, Qichao Zhang, Yaocheng Zhang, Jiajun Chai, Xiaohan Wang, Wei Lin, Guojun Yin, Dongbin Zhao
SRFT: A Single-Stage Method with Supervised and Reinforcement Fine-Tuning for Reasoning
Yuqian Fu*, Tinghong Chen*, Jiajun Chai, Xihuai Wang, Songjun Tu, Guojun Yin, Wei Lin, Qichao Zhang, Yuanheng Zhu, Dongbin Zhao
ResT: Reshaping Token-Level Policy Gradients for Tool-Use Large Language Models
Zihan Lin*, Xiaohan Wang*, Jie Cao, Jiajun Chai, Guojun Yin#, Wei Lin, Ran He
SAE as a Crystal Ball: Interpretable Features Predict Cross-domain Transferability of LLMs without Training
Qi Zhang*, Yifei Wang*, Xiaohan Wang, Jiajun Chai, Guojun Yin, Wei Lin, Yisen Wang
ViPER: Empowering the Self-Evolution of Visual Perception Abilities in Vision-Language Model
Juntian Zhang, Song Jin, Chuanqi Cheng, Yuhan Liu, Yankai Lin, Xun Zhang, Yufei Zhang, Fei Jiang, Guojun Yin, Wei Lin, Rui Yan
LogiConBench: Benchmarking Logical Consistencies of LLMs
Zheng Chen, Chuan Zhou, Fengxiang Cheng, Yip Tin Po, Fenrong Liu, Yisen Wang, Jiajun Chai, Xiaohan Wang, Guojun Yin, Wei Lin, Bo Li, Haoxuan Li, Zhouchen Lin
MAD-Logic: Multi-Agent Debate Enhances Symbolic Translation and Reasoning
Haocheng Yang, Fengxiang Cheng, Tianjun Yao, Mengyue Yang, Jiajun Chai, Xiaohan Wang, Guojun Yin, Wei Lin, Soummya Kar, Fenrong Liu*, Haoxuan Li*, Yisen Wang*
MTIR-SQL: Multi-turn Tool-Integrated Reasoning Reinforcement Learning for Text-to-SQL
Zekun Xu*, Siyu Xia*, Chuhuai Yue, Jiajun Chai, Mingxue Tian, Xiaohan Wang, Wei Lin, Haoxuan Li, Guojun Yin#
Promoting Efficient Reasoning with Verifiable Stepwise Reward
Chuhuai Yue, Chengqi Dong, Yinan Gao, Hang He, Jiajun Chai, Guojun Yin#, Wei Lin
RLAE: Reinforcement Learning-Assisted Ensemble for LLMs
Yuqian Fu, Yuanheng Zhu, Jiajun Chai, Guojun Yin, Wei Lin, Qichao Zhang, Dongbin Zhao
Beyond Static Testbeds: An Interaction-Centric Agent Simulation Platform for Dynamic Recommender Systems
Song Jin*, Juntian Zhang*, Yuhan Liu, Xun Zhang, Yufei Zhang, Guojun Yin, Fei Jiang, Wei Lin, Rui Yan
UIOrchestra: Generating High-Fidelity Code from UI Designs with a Multi-agent System
Chuhuai Yue, Jiajun Chai, Yufei Zhang, Zixiang Ding, Xihao Liang, Peixin Wang, Shihai Chen, Wang Yixuan, Yanping Wang, Guojun Yin, Wei Lin
PolarQuant: Leveraging Polar Transformation for Efficient Key Cache Quantization and Decoding Acceleration
Songhao Wu*, Ang Lv*, Xiao Feng, Yufei Zhang, Xun Zhang, Guojun Yin#, Wei Lin, Rui Yan
Semantic Convergence: Harmonizing Recommender Systems via Two-Stage Alignment and Behavioral Semantic Tokenization
Guanghan Li, Xun Zhang, Yufei Zhang, Yifan Yin, Guojun Yin#, Wei Lin
Dual-level Modality Debiasing Learning for Unsupervised Visible-Infrared Person Re-Identification
Jiaze Li, Yan Lu, Bin Liu, Guojun Yin, Mang Ye
Tri2-plane: Thinking Head Avatar via Feature Pyramid
Luchuan Song, Pinxin Liu, Lele Chen, Guojun Yin, Chenliang Xu
Adaptive Super Resolution for One-Shot Talking-Head Generation
Luchuan Song, Pinxin Liu, Guojun Yin, Chenliang Xu
Emotional Listener Portrait: Realistic Listener Motion Simulation in Conversation
Luchuan Song, Guojun Yin, Zhenchao Jin, Xiaoyi Dong, Chenliang Xu
Counterfactual Intervention Feature Transfer for Visible-Infrared Person Re-identification
Xulin Li, Yan Lu, Bin Liu, Yating Liu, Guojun Yin, Qi Chu, Jinyang Huang, Feng Zhu, Rui Zhao, Nenghai Yu
TACR-Net: Editing on Deep Video and Voice Portraits
Luchuan Song, Bin Liu, Guojun Yin, Xiaoyi Dong, Yufei Zhang, Jiaxu Bai
ForgeryNet: A Versatile Benchmark for Comprehensive Forgery Analysis
Yinan He, Bei Gan, Siyu Chen, Yichun Zhou, Guojun Yin, Luchuan Song, Lu Sheng, Jing Shao, Ziwei Liu
Thinking in Frequency: Face Forgery Detection by Mining Frequency-aware Clues
Yuyang Qian*, Guojun Yin*#, Lu Sheng#, Zixuan Chen*, Jing Shao
CelebA-Spoof: Large-Scale Face Anti-Spoofing Dataset with Rich Annotations
Yuanhan Zhang, Zhenfei Yin, Yidong Li, Guojun Yin, Junjie Yan, Jing Shao, Ziwei Liu
Learning to Predict Layout-to-image Conditional Convolutions for Semantic Image Synthesis
Xihui Liu, Guojun Yin, Jing Shao, Xiaogang Wang, Hongsheng Li
Semantics Disentangling for Text-to-Image Generation
Guojun Yin, Bin Liu, Lu Sheng, Nenghai Yu, Xiaogang Wang, Jing Shao
Context and Attribute Grounded Dense Captioning
Guojun Yin, Lu Sheng, Bin Liu, Nenghai Yu, Xiaogang Wang, Jing Shao
FD-GAN: Pose-guided Feature Distilling GAN for Robust Person Re-identification
Yixiao Ge*, Zhuowan Li*, Haiyu Zhao, Guojun Yin, Shuai Yi, Xiaogang Wang, Hongsheng Li
Zoom-Net: Mining Deep Feature Interactions for Visual Relationship Recognition
Guojun Yin, Lu Sheng, Bin Liu, Nenghai Yu, Xiaogang Wang, Jing Shao, Chen Change Loy
Education
Ph.D.
EE, USTC
2014.09 - 2019.07
Hefei
Research Assistant
2017.06 - 2018.09
Hong Kong
Bachelor
EE, USTC
2010.09 - 2014.06
Hefei
