News


Feb 2025
The toolkit for implementing fairness and diverse IR algorithms have been published in github and Arvix. It contains fairness and diversity 28 models with 16 IR base models! If you are intested, please give a try!

Jan 2025
One paper about Federated Learning for LLMs-based recommender systems has been accepted in NAACL findings! Congrats to Jujia!

Jan 2025
One paper about fairness for LLMs-based recommender systems has been accepted in ICLR2025! Thanks to all the contributors!

Sep 2024
I am joining the IRLab as a visiting PhD student in 2024.10.17 ! Prof. Maarten de Rijke will be his host. I will be working on fairness in recommender systems.

Sep 2024
One paper about implicit fairness for LLMs-based recommender systems has been accepted in EMNLP 2024 findings! Thanks to all the contributors!

August 2024
One paper about long-term fairness in recommendation has been accepted in TOIS 2024! Thanks to all the contributors!

July 2024
I will visit the University of Amsterdam, and be supervised by Prof. Maarten de Rijke in Oct 2024

July 2024
One paper about fairness re-ranking has been accepted in CIKM 2024! Congratulations to Xiaopeng on his first paper!

July 2024
One full paper is awarded as SIGIR 2024 Best Paper Honorable Mention! Thanks to all the contributors!

April 2024
One full paper is accepted in SIGIR2024, about fairness re-ranking models.

Jan 2023
One full paper is accepted in WWW2024, about fairness in retrieval process.

Chen Xu (徐晨)

PhD Student

IIR Lab
Gaoling School of Artificial Intelligence
Renmin University of China

Renmin University of China, No. 59 Zhongguancun Street, Haidian District, Beijing, China, 100872

Email: chenxu0427ruc AT gmail.com/xc_chen AT ruc.edu.cn
Google ScholarGitHub

I am a Ph.D. student, supervised by Prof. Jun Xu. Prior to that, I received a double Bachelor's Degree in engineering and economics. My research interests include information retrieval, fairness.

Education

Renmin University of China
Ph.D. in Computer Science, 2021 - present, China
Advisor: Prof. Jun Xu
Renmin University of China
Bachelor in Computer Science and Economics, 2017 - 2021, China
Advisor: Prof. Jun Xu

Experiences

Visiting Ph.D. Student, NExT++ Lab, National University of Singapore Sep 2023 - July 2024
Advisor: Prof. Tat-Seng Chua Mentors: Dr. Wenjie Wang
Visiting Ph.D. Student, IRLab, University of Amsterdam Oct 2024 - Apr 2025
Advisor: Prof. Maarten de Rijke

Toolkits and Software


pdf
FairDiverse: A Comprehensive Toolkit for Fair and Diverse Information Retrieval Algorithms Chen Xu, Zhirui Deng, Clara Rus, Xiaopeng Ye, Yuanna Liu, Jun Xu*, Zhicheng Dou*, Ji-Rong Wen, Maarten de Rijke
Github, Documents

Tutorials, Surveys, and Workshops


pdf
Bias and Unfairness in Information Retrieval Systems: New Challenges in the LLM Era
Sunhao Dai, Chen Xu, Shicheng Xu, Liang Pang, Jun Xu, Zhenhua Dong
KDD2024; Survey Link

Publications Google Scholar

   *Corresponding author

pdf
Bridging Jensen Gap for Max-Min Group Fairness Optimization in Recommendation
Chen Xu, Yuxin Li, Wenjie Wang, Liang Pang, Jun Xu*, Tat-Seng Chua
ICLR 2025

pdf
A Study of Implicit Ranking Unfairness in Large Language Models
Chen Xu, Wenjie Wang, Yuxin Li, Liang Pang, Jun Xu*, Tat-Seng Chua
EMNLP findings 2024

pdf
A Taxation Perspective for Fair Re-ranking
Chen Xu, Xiaopeng Ye, Wenjie Wang*, Liang Pang, Jun Xu*, Tat-Seng Chua
SIGIR 2024 (Best Paper Honorable Mention)

pdf
BankFair: Balancing Accuracy and Fairness under Varying User Traffic in Recommender System
Xiaopeng Ye, Chen Xu, Jun Xu*, Xuyang Xie, Gang Wang, Zhenhua Dong
CIKM 2024

pdf
FairSync: Ensuring Amortized Group Exposure in Distributed Recommendation Retrieval
Chen Xu, Jun Xu*, Yiming Ding, Xiao Zhang, Qi Qi
WWW 2024

pdf
LTP-MMF: Towards Long-term Provider Max-min Fairness Under Recommendation Feedback Loops
Chen Xu, Xiaopeng Ye, Jun Xu*, Xiao Zhang, Weiran Shen, Ji-Rong Wen
TOIS 2024

pdf
Syntactic-Informed Graph Networks for Sentence Matching
Chen Xu, Jun Xu*, Zhenhua Dong, Ji-Rong Wen
TOIS 2023

pdf
Llm-based federated recommendation
Jujia Zhao, Wenjie Wang*, Chen Xu*, See-Kiong Ng, Tat-Seng Chua
NAACL2025 findings

pdf
P-MMF: Provider Max-min Fairness Re-ranking in Recommender System
Chen Xu, Sirui Chen, Jun Xu*, Weiran Shen, Xiao Zhang, Gang Wang, Zhenhua Dong
WWW 2023 (Spotlight-Best Paper Candidates)

pdf
Uncovering chatgpt’s capabilities in recommender systems
Sunhao Dai, Ninglu Shao, Haiyuan Zhao, Weijie Yu, Zihua Si, Chen Xu, Zhongxiang Sun, Xiao Zhang, Jun Xu
Recsys 2023 FAST track

pdf
Dually Enhanced Propensity Score Estimation in Sequential Recommendation
Chen Xu, Jun Xu*, Xu Chen, Zhenhua Dong, Ji-Rong Wen
CIKM 2022

pdf
Semantic Sentence Matching via Interacting Syntax Graphs
Chen Xu, Jun Xu*, Zhenhua Dong, Ji-Rong Wen
COLING 2022

Professional Services

Invited Reviewer for TOIS, TIST, TKDE, JISIST, JIR
Program Committee Member of CIKM, EMNLP, KDD, WWW

Honors

Best Paper Honorable Mention in SIGIR 2024;
Spotlights-Best Paper Candidates in WWW 2023 ;
National Scholarship in China, 2023
National Scholarship in China, 2024

Last update: Oct, 2023. Webpage template borrows from Prof. Xiangnan He.