1,538 research outputs found
Continual Learning with Invertible Generative Models
Catastrophic forgetting (CF) happens whenever a neural network overwrites
past knowledge while being trained on new tasks. Common techniques to handle CF
include regularization of the weights (using, e.g., their importance on past
tasks), and rehearsal strategies, where the network is constantly re-trained on
past data. Generative models have also been applied for the latter, in order to
have endless sources of data. In this paper, we propose a novel method that
combines the strengths of regularization and generative-based rehearsal
approaches. Our generative model consists of a normalizing flow (NF), a
probabilistic and invertible neural network, trained on the internal embeddings
of the network. By keeping a single NF throughout the training process, we show
that our memory overhead remains constant. In addition, exploiting the
invertibility of the NF, we propose a simple approach to regularize the
network's embeddings with respect to past tasks. We show that our method
performs favorably with respect to state-of-the-art approaches in the
literature, with bounded computational power and memory overheads.Comment: arXiv admin note: substantial text overlap with arXiv:2007.0244
Recurrent Highway Networks
Many sequential processing tasks require complex nonlinear transition
functions from one step to the next. However, recurrent neural networks with
'deep' transition functions remain difficult to train, even when using Long
Short-Term Memory (LSTM) networks. We introduce a novel theoretical analysis of
recurrent networks based on Gersgorin's circle theorem that illuminates several
modeling and optimization issues and improves our understanding of the LSTM
cell. Based on this analysis we propose Recurrent Highway Networks, which
extend the LSTM architecture to allow step-to-step transition depths larger
than one. Several language modeling experiments demonstrate that the proposed
architecture results in powerful and efficient models. On the Penn Treebank
corpus, solely increasing the transition depth from 1 to 10 improves word-level
perplexity from 90.6 to 65.4 using the same number of parameters. On the larger
Wikipedia datasets for character prediction (text8 and enwik8), RHNs outperform
all previous results and achieve an entropy of 1.27 bits per character.Comment: 12 pages, 6 figures, 3 table
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