Outer Product-based Neural Collaborative Filtering
This work addresses the challenge of building more expressive recommender systems for users, though it appears incremental as it builds upon existing neural methods with a novel architectural tweak.
The authors tackled the problem of collaborative filtering by proposing a new neural network architecture, ONCF, that uses an outer product to model pairwise correlations between embedding dimensions, achieving improved performance on two public implicit feedback datasets.
In this work, we contribute a new multi-layer neural network architecture named ONCF to perform collaborative filtering. The idea is to use an outer product to explicitly model the pairwise correlations between the dimensions of the embedding space. In contrast to existing neural recommender models that combine user embedding and item embedding via a simple concatenation or element-wise product, our proposal of using outer product above the embedding layer results in a two-dimensional interaction map that is more expressive and semantically plausible. Above the interaction map obtained by outer product, we propose to employ a convolutional neural network to learn high-order correlations among embedding dimensions. Extensive experiments on two public implicit feedback data demonstrate the effectiveness of our proposed ONCF framework, in particular, the positive effect of using outer product to model the correlations between embedding dimensions in the low level of multi-layer neural recommender model. The experiment codes are available at: https://github.com/duxy-me/ConvNCF