2020/06/21 by Shiyang Yan, Hua Yang, Yan, Shiyang +3
Computer Science · #Computer Vision and Pattern Recognition (cs.CV) #Domain Adaptation and Few-Shot Learning #FOS: Computer and information sciences #Machine Learning (cs.LG) #Multimodal Machine Learning Applications #Topic Modeling
paper · pdf · doi:10.48550/arxiv.2006.11714
openalex publication_date 2020/06/21 · openalex created_date 2020/06/25 · openalex updated_date 2026/07/28
Recently, several approaches have been proposed to solve language generation problems. Transformer is currently state-of-the-art seq-to-seq model in language generation. Reinforcement Learning (RL) is useful in solving exposure bias and the optimisation on non-differentiable metrics in seq-to-seq language learning. However, Transformer is hard to combine with RL as the costly computing resource is required for sampling. We tackle this problem by proposing an off-policy RL learning algorithm where a behaviour policy represented by GRUs performs the sampling. We reduce the high variance of importance sampling (IS) by applying the truncated relative importance sampling (TRIS) technique and Kullback-Leibler (KL)-control concept. TRIS is a simple yet effective technique, and there is a theoretical proof that KL-control helps to reduce the variance of IS. We formulate this off-policy RL based on self-critical sequence training. Specifically, we use a Transformer-based captioning model as the target policy and use an image-guided language auto-encoder as the behaviour policy to explore the environment. The proposed algorithm achieves state-of-the-art performance on the visual paragraph generation and improved results on image captioning.