Improving Meta-Continual Learning Representations with Representation Replay

Lawrence Ki-On Chan, James Kwok

Keywords: meta-learning, continual learning, meta-continual learning, replay

Abstract: Continual learning often suffers from catastrophic forgetting. Recently, meta-continual learning algorithms use meta-learning to learn how to continually learn. A recent state-of-the-art is online aware meta-learning (OML). This can be further improved by incorporating experience replay (ER) into its meta-testing. However, the use of ER only in meta-testing but not in meta-training suggests that the model may not be optimally meta-trained. In this paper, we remove this inconsistency in the use of ER and improve continual learning representations by integrating ER also into meta-training. We propose to store the samples' representations, instead of the samples themselves, into the replay buffer. This ensures the batch nature of ER does not conflict with the online-aware nature of OML. Moreover, we introduce a meta-learned sample selection scheme to replace the widely used reservoir sampling to populate the replay buffer. This allows the most significant samples to be stored, rather than relying on randomness. Class-balanced modifiers are further added to the sample selection scheme to ensure each class has sufficient samples stored in the replay buffer. Experimental results on a number of real-world meta-continual learning benchmark data sets demonstrate that the proposed method outperforms the state-of-the-art. Moreover, the learned representations have better clustering structures and are more discriminative.

One-sentence Summary: We propose the Online aware Meta-Representation Replay (OMREP) to meta-learn representations for continual learning and the Predictive Sample Selection (PSS) to select the most significant samples for replay.