A C-LSTM Neural Network for Text Classification
Chunting Zhou, Chonglin Sun, Zhiyuan Liu, Francis C. M. Lau
TL;DR
The paper presents C-LSTM, a unified architecture that couples a one-layer CNN for local n-gram feature extraction with an LSTM to model sequential dependencies among the resulting window representations. This end-to-end model is evaluated on SST sentiment and TREC question classification, where it outperforms single CNN/LSTM baselines and remains competitive with parse-tree–based methods, demonstrating strong long-range dependency capture without linguistic annotations. Key contributions include demonstration of the effectiveness of feeding sequences of higher-level CNN features into an LSTM, analysis of filter-size configurations, and showing robustness across different text classification tasks. The work suggests that richer, structured higher-level representations can significantly boost sentence-level classification performance and points to future extensions with tensor-based or tree-structured convolutional components.
Abstract
Neural network models have been demonstrated to be capable of achieving remarkable performance in sentence and document modeling. Convolutional neural network (CNN) and recurrent neural network (RNN) are two mainstream architectures for such modeling tasks, which adopt totally different ways of understanding natural languages. In this work, we combine the strengths of both architectures and propose a novel and unified model called C-LSTM for sentence representation and text classification. C-LSTM utilizes CNN to extract a sequence of higher-level phrase representations, and are fed into a long short-term memory recurrent neural network (LSTM) to obtain the sentence representation. C-LSTM is able to capture both local features of phrases as well as global and temporal sentence semantics. We evaluate the proposed architecture on sentiment classification and question classification tasks. The experimental results show that the C-LSTM outperforms both CNN and LSTM and can achieve excellent performance on these tasks.
