9,868 research outputs found
Attentive Convolution: Equipping CNNs with RNN-style Attention Mechanisms
In NLP, convolutional neural networks (CNNs) have benefited less than
recurrent neural networks (RNNs) from attention mechanisms. We hypothesize that
this is because the attention in CNNs has been mainly implemented as attentive
pooling (i.e., it is applied to pooling) rather than as attentive convolution
(i.e., it is integrated into convolution). Convolution is the differentiator of
CNNs in that it can powerfully model the higher-level representation of a word
by taking into account its local fixed-size context in the input text t^x. In
this work, we propose an attentive convolution network, ATTCONV. It extends the
context scope of the convolution operation, deriving higher-level features for
a word not only from local context, but also information extracted from
nonlocal context by the attention mechanism commonly used in RNNs. This
nonlocal context can come (i) from parts of the input text t^x that are distant
or (ii) from extra (i.e., external) contexts t^y. Experiments on sentence
modeling with zero-context (sentiment analysis), single-context (textual
entailment) and multiple-context (claim verification) demonstrate the
effectiveness of ATTCONV in sentence representation learning with the
incorporation of context. In particular, attentive convolution outperforms
attentive pooling and is a strong competitor to popular attentive RNNs.Comment: Camera-ready for TACL. 16 page
On Tree-Based Neural Sentence Modeling
Neural networks with tree-based sentence encoders have shown better results
on many downstream tasks. Most of existing tree-based encoders adopt syntactic
parsing trees as the explicit structure prior. To study the effectiveness of
different tree structures, we replace the parsing trees with trivial trees
(i.e., binary balanced tree, left-branching tree and right-branching tree) in
the encoders. Though trivial trees contain no syntactic information, those
encoders get competitive or even better results on all of the ten downstream
tasks we investigated. This surprising result indicates that explicit syntax
guidance may not be the main contributor to the superior performances of
tree-based neural sentence modeling. Further analysis show that tree modeling
gives better results when crucial words are closer to the final representation.
Additional experiments give more clues on how to design an effective tree-based
encoder. Our code is open-source and available at
https://github.com/ExplorerFreda/TreeEnc.Comment: To Appear at EMNLP 201
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