Sixiao Zhang

PhD candidate at Nanyang Technological University.

I am a PhD candidate at Nanyang Technological University, supervised by Prof. Cheng Long. My research lies at the intersection of recommender systems, conversational AI, and generative language modeling. I am particularly interested in building fully generative recommender systems that unify recommendation and dialogue generation within large language models.

My recent work focuses on semantic ID based recommendation generation, structured conversational reasoning, and controllable recommendation behaviors in autoregressive generation frameworks. I also work on trustworthy recommendation systems, including model extraction attacks and watermarking techniques for recommendation models.

More broadly, I am interested in developing next-generation recommendation systems that move beyond traditional retrieval pipelines toward integrated generative intelligence.

Services & Awards

  • Program Committee & Reviewer: NeurIPS (2026), AAAI (2026), KDD (2025,2026), WWW (2025), ACM MM (2025), CIKM (2024,2026), TIFS, DKE, etc.

  • 2025 SIGKDD Student Travel Grant.

  • Nanyang Technological University Research Scholarship.

selected publications

  1. Generative Conversational Recommender System
    Sixiao Zhang, Mingrui Liu, and Cheng Long
    arXiv preprint arXiv:2605.21987, 2026
    arXiv
  2. Data watermarking for sequential recommender systems
    Sixiao Zhang, Cheng Long, Wei Yuan, and 2 more authors
    In Proceedings of the 31st ACM SIGKDD Conference on Knowledge Discovery and Data Mining V. 2, 2025
    arXiv
  3. On Mitigating Data Sparsity in Conversational Recommender Systems
    Sixiao Zhang, Mingrui Liu, Cheng Long, and 4 more authors
    arXiv preprint arXiv:2507.00479, 2025
    arXiv
  4. Watermarking Recommender Systems
    Sixiao Zhang, Cheng Long, Wei Yuan, and 2 more authors
    In Proceedings of the 33rd ACM International Conference on Information and Knowledge Management, 2024
    arXiv
  5. Defense against model extraction attacks on recommender systems
    Sixiao Zhang, Hongzhi Yin, Hongxu Chen, and 1 more author
    In Proceedings of the 17th ACM International Conference on web search and data mining, 2024
    arXiv
  6. Unsupervised graph poisoning attack via contrastive loss back-propagation
    Sixiao Zhang, Hongxu Chen, Xiangguo Sun, and 2 more authors
    In Proceedings of the ACM Web Conference 2022, 2022
    arXiv
  7. Where are we in embedding spaces?
    Sixiao Zhang, Hongxu Chen, Xiao Ming, and 3 more authors
    In Proceedings of the 27th ACM SIGKDD Conference on Knowledge Discovery & Data Mining, 2021
    arXiv