RAG-DDR: Optimizing Retrieval-Augmented Generation Using Differentiable Data Rewards - Li, Xinze; Mei, Sen; Liu, Zhenghao; Yan, Yukun; Wang, Shuo; Yu, Shi; Zeng, Zheni; Chen, Hao; Yu, Ge; Liu, Zhiyuan; Sun, Maosong; Xiong, Chenyan (International Conference on Learning Representations, 2025)