News
20 July 2026
Got one paper accepted at TKDE about Continual Pre-training in LLM4Rec.
22 May 2026
Got one paper accepted at Journal of Software about Multi-modal Recommendation.
18 April 2026
Got one paper accepted at TOIS about Debiased Bundle Construction. Big congrats to Xu Shuo and other collaborators!
06 April 2026
Got one paper accepted at ACL 2026 about MLLM Continual Learning. Big congrats to Zhiyan and other collaborators!
19 January 2026
Got one paper accepted at TOIS about Negative Sampling in Recommendation.
24 November 2025
Got one paper accepted at KDD 2026 about Diffusion Model and Cross-domain Recommendation. Big congrats to Yongfu and other collaborators!
21 December 2024
Got two papers accepted at AAAI about Diffusion-based Negative Sampling in Recommendation and Multi-modal Alignment in Classification.
21 July 2024
Got one paper accepted at ACMMM about causal representation in Video Classification.
17 April 2024
Got one paper accepted at IJCAI about diffusion model in Sequential Recommendation and Cross-domain Recommendation.
9 December 2023
Got one paper accepted at AAAI about Diffusion Model in Sequential Recommendation and Cross-domain Recommendation.
4 December 2023
Got one paper accepted at TOIS about Triple Sequence Modeling in Cross-domain Recommendation.
21 September 2023
Got one paper accepted at Journal of Software about cross-modal learning in Classification.
21 June 2023
Got one paper accepted at Recsys 2023 about negative sampling in Cross-domain Recommendation.
7 April 2023
Got one paper accepted at IJCNN 2023 about cross-modal learning in Cold-start Recommendation.
7 December 2022
Got one paper accepted at CVM 2023 about cross-modal learning in Long-tailed Classification.
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Haokai Ma
Postdoctoral Research Fellow NExT++ Research Center / NCL National University of Singapore
Email: haokai.ma1997@gmail.com
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I am a Postdoctoral Research Fellow in National University of Singapore (NUS), where I am a member of NExT++ Research Center, supervised by Prof. Chua Tat-Seng. I am also under National Cybersecurity R&D Lab, where I work with Prof. Chang Ee-Chien. Before that, I had received my Ph.D. degree in Shandong University in June 2024, supervised by Prof. Meng Lei. My research interests span Recommender System, the safety and security issues within Agent/MAS, and the application of LLMs in Cybersecurity. I have more than 40 publications appeared in several top conferences such as KDD, ICLR, AAAI, and ACL, and journals including TOIS, TKDE and Journal of Software. I have been invited as the reviewer for NeurIPS, ICLR, ICML, ACL, AAAI, TKDE and TOIS, and the Regular PC for Recsys Reproducibility track and Demo track. Moreover, I serve as the Student Volunteer Co-chair in ICAIF 2025 and the Session Chair in IJCAI and IJCNN.
I am looking for highly motivated PhD/master/undergraduate students to collaborate on various Recommendation scenarios, the security issues within Agent/Multi-Agent System, as well as on the application of LLMs in Cybersecurity (CTI Report Understanding and Confidence Faithfulness in High-stakes Domains). If you have interest, please feel free to send your CV to haokai.ma1997@gmail.com. All CVs will be carefully treated!
We reveal how deceptive agent descriptions compromise planning in centralized MAS: - Misleading the Planner through Deceptive Resumes: Registration-Time Injection in Centralized Multi-Agent Systems
We have released a survey on the negative sampling strategies of Recsys: - Negative Sampling in Recommendation: A Survey and Future Directions
We are excited to introduce a new benchmark to evaluate the capabilities of LLMs for attack sequences understanding: - AttackSeqBench: Benchmarking the Capabilities of LLMs for Attack Sequences Understanding
We have organized the 6th ACM International Conference on AI in Finance in Singapore: - The 6th ACM International Conference on AI in Finance (ICAIF 2025)
We reveal how deceptive agent descriptions compromise planning in centralized MAS: - Misleading the Planner through Deceptive Resumes: Registration-Time Injection in Centralized Multi-Agent Systems
We have released a survey on the negative sampling strategies of Recsys: - Negative Sampling in Recommendation: A Survey and Future Directions
We are excited to introduce a new benchmark to evaluate the capabilities of LLMs for attack sequences understanding: - AttackSeqBench: Benchmarking the Capabilities of LLMs for Attack Sequences Understanding
We have organized the 6th ACM International Conference on AI in Finance in Singapore: - The 6th ACM International Conference on AI in Finance (ICAIF 2025)
Tutorials & Workshops
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International Workshop on Multimodal Generative Search and Recommendation
Yi Bin, Haoxuan Li, Haokai Ma, Yang Zhang, Wenjie Wang, Yunshan Ma, Yang Yang & Tat-Seng Chua CIKM 2025 [Web Page] |
Preprints
(# indicates equal contribution and * indicates corresponding author) |
Less Data Approximates More: Earning Faithful Confidence in High-Stakes Domains
Haokai Ma, Lee Yan Zhen, Gang Yang, Yunxiang Chen, Yunshan Ma, Ee-Chien Chang* & Tat-Seng Chua Arxiv [Paper] |
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Benchmarking the Capabilities of LLMs for Attack Sequence Understanding
Haokai Ma, Javier Yong, Yunshan Ma, Kuei Chen, Anis Yusof, Zhenkai Liang & Ee-Chien Chang Arxiv [Paper] |
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EchoRec: Multi-Item Prediction-Empowered Generative Recommendation via Cycle-Consistent Preference Alignment
Haokai Ma#, Aoqi Hu#, Yueao Xing, Ruobing Xie, Yonghui Yang, Teng Tu, Lei Meng & Tat-Seng Chua Arxiv [Paper] |
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Misleading the Planner through Deceptive Resumes: Registration-Time Injection in Centralized Multi-Agent Systems
Zhaofeng Yu, Haokai Ma*, Dongyang Zhan, Hongli Zhang, Han Fang & Ee-Chien Chang Arxiv [Paper] |
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MealRec: Multi-granularity Sequential Modeling via Hierarchical Diffusion Models for Micro-Video Recommendation
Xinxin Dong, Haokai Ma*, Yuze Zheng, Yongfu Zha, Yonghui Yang & Xiaodong Wang Arxiv [Paper] |
Selected Publications
(# indicates equal contribution and * indicates corresponding author) |
Large Language Model Empowered Recommendation Meets All-domain Continual Pre-Training
Haokai Ma, Yunshan Ma, Ruobing Xie*, Lei Meng, Jialie Shen, Xingwu Sun, Zhanhui Kang & Tat-Seng Chua IEEE Transactions on Knowledge and Data Engineering (TKDE) [Paper] |
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Negative Sampling in Recommendation: A Survey and Future Directions
Haokai Ma, Ruobing Xie, Lei Meng*, Fuli Feng, Xiaoyu Du, Xingwu Sun, Zhanhui Kang & Xiangxu Meng ACM Transactions on Information Systems (TOIS) [Paper] [Github Repo] |
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Align-for-Fusion: Harmonizing Triple Preferences via Dual-oriented Diffusion for Cross-domain Sequential Recommendation
Yongfu Zha, Xinxin Dong, Haokai Ma*, Yonghui Yang & Xiaodong Wang ACM SIGKDD Conference on Knowledge Discovery and Data Mining 2026 (KDD 2026) Oral [Code] |
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PASs-MoE: Mitigating Misaligned Co-drift among Router and Experts via Pathway Activation Subspaces for Continual Learning
ZhiYan Hou, Haiyun Guo*, Haokai Ma*, Yandu Sun, Yonghui Yang & Jinqiao Wang The 64th Annual Meeting of the Association for Computational Linguistics (ACL 2026) [Paper] [Code] |
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Promoting Long-tail Items through Debiased Product Bundling
Shuo Xu#, Haokai Ma#, Yunshan Ma, Xiaohao Liu, Lei Meng*, Xiangxu Meng & Tat-Seng Chua ACM Transactions on Information Systems (TOIS) [Paper] [Code] |
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Plug-in Diffusion Model for Sequential Recommendation
Haokai Ma, Ruobing Xie, Lei Meng*, Xin Chen, Xu Zhang, Leyu Lin & Zhanhui Kang The 38th AAAI Conference on Artificial Intelligence (AAAI) 2024 [Codes] |
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SeeDRec: Sememe-based Diffusion for Sequential Recommendation
Haokai Ma, Ruobing Xie*, Lei Meng*, Yimeng Yang, Xingwu Sun & Zhanhui Kang The 33rd International Joint Conference on Artificial Intelligence (IJCAI) 2024 [Codes] |
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Multimodal Conditioned Diffusion Model for Recommendation
Haokai Ma#, Yimeng Yang#, Lei Meng*, Ruobing Xie & Xiangxu Meng The 2nd Workshop on Recommendation with Generative Models (in conjunction with WWW '24) [Codes] |
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Triple Sequence Learning for Cross-domain Recommendation
Haokai Ma#, Ruobing Xie#, Lei Meng*, Xin Chen, Xu Zhang, Leyu Lin & Jie Zhou ACM Transactions on Information Systems (TOIS) [Codes] |
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Exploring False Hard Negative Sample in Cross-Domain Recommendation
Haokai Ma, Ruobing Xie, Lei Meng*, Xin Chen, Xu Zhang, Leyu Lin & Jie Zhou 17th ACM Conference on Recommender Systems (Recsys) 2023 [Codes] |
Professional Services
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Conference/Workshop Organization: Workshop Organizer of MMGenSR 2025 in CIKM 2025. Student Volunteer Chair of ICAIF 2025. Session Chair of IJCAI 2024 in Recommendation. Session Chair of IJCNN 2023 in Recommendation. |
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Invited Reviewer for Conferences and Journals: 2026: NeurIPS, ICLR, ARR, AAAI, ACMMM, IJCAI, TKDE, TOIS 2025: NeurIPS, ACL, ACMMM, AAAI, Recsys, TKDE, TOIS 2024: IJCAI, ACMMM, Recsys, IJCNN, TKDE, IPM, JASIST 2023: IJCNN, TKDD 2022: AAAI |
Honors and Awards
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2025.10: Outstanding Doctoral Dissertation Award, Shandong Computer Federation 2024.06: Outstanding Graduate of Shandong University, Shandong University 2022.04: Tencent Rhino-Bird Research Elite Program (72 nationwide selectees), Tencent 2022.04: First Prize of the 3rd Shandong Province Big Data Intelligence Competition for College Students, National Supercomputing Center in Jinan 2021.10: Student Travel Grant, SIGMM Executive Committee 2020.11: Advanced Individual in Graduate Research and Innovation, School of Software |
Experiences
| National University of Singapore (NUS) Postdoctoral Research Fellow Feb. 2025 - NExT++ Research Center / National Cybersecurity R&D Lab (NCL) Advisiors: Prof. Chua Tat-Seng and Prof. Chang Ee-Chien |
| WeiXin Group, Tencent (Tencent Rhino-Bird Research Elite Program) Research Intern May. 2022 - Nov. 2023 Advisior: Ruobing Xie |
Education
| Shandong University (SDU) Ph.D. in Software Engineering Sep. 2019 - Jun. 2024 Advisor: Prof. Lei Meng |
| Shandong University (SDU) B.S. in Software Engineering Sep. 2015 - Jun. 2019 |
Useful Links
| NUS CS Conference Rankings |
| NUS CS Journal Ranking |
| NUS CS Courses |
| Machine Learning Reading List |
| Deep Learning Reading List |
Last update: 23 October, 2025. Webpage template borrows from Prof. Xiangnan He.