Xinyi Ni

Xinyi Ni

Biography

I am currently a Machine Learning Scientist in industry, with continued interest in academic research. If you have exciting ideas or potential collaboration opportunities, feel free to reach out. I’m always happy to connect and explore new directions.

I completed my Ph.D. in ECE at UC Davis in Dec 2024, under the supervision of Prof. Lifeng Lai. My research focuses on risk-sensitive reinforcement learning (RL), enhancing algorithmic efficiency, sample complexity, and robustness.I also explored risk-sensitive RL in diverse settings, including reward-free frameworks and with human feedback (RLHF). During my internship at Microsoft, I applied large language model (LLM) reasoning and causal analysis to innovate on AI-driven game testing techniques.

I received my Bachelor’s degree in Information Engineering from Zhejiang University, China, in 2019. I collaborated with Prof. Jiangtao Huangfu on integrating deep learning (DL) into medical image diagnosis and autonomous driving.

Preprint

  • Xinyi Ni and Lifeng Lai. “Risk-Sensitive Reinforcement Learning with Coherent Risk Measures.” Ph.D Thesis. 2025. University of California, Davis. Paper
  • Xinyi Ni and Lifeng Lai. “Risk-Sensitive Reinforcement Learning with $\phi$-Divergence-Risk.” IEEE Transaction on Information Theory. 2024. Submitted. Paper

Publications

  • Xinyi Ni, Guanlin Liu and Lifeng Lai. “Risk-Sensitive Reward-Free Reinforcement Learning with CVaR.” International Conference on Machine Learning (ICML). 2024. Paper
  • Xinyi Ni and Lifeng Lai. “Robust Risk-Sensitive Reinforcement Learning with Conditional Value-at-Risk.” IEEE Information Theory Workshop (ITW) 2024. Paper
  • Xinyi Ni and Lifeng Lai. “Policy Gradient Based Entropic-VaR Optimization in Risk-Sensitive Reinforcement Learning.” Allerton Conference on Communication, Control, and Computing. IEEE, 2022. Paper
  • Xinyi Ni and Lifeng Lai. “Risk-sensitive reinforcement learning via Entropic-VaR optimization.” Asilomar Conference on Signals, Systems, and Computers. IEEE, 2022. Paper
  • Xinyi Ni and Lifeng Lai. “EVaR Optimization for Risk-Sensitive Reinforcement Learning.” UC Davis, 2021. Paper

Academic Activities

Reviewer

  • International Conference on Machine Learning (ICML)
  • IEEE Transactions on Information Theory
  • IEEE Transactions on Mobile Computing
  • IEEE Control Systems Letters