Deep Feature Fusion over Multi-field Categorical Data for Rating Prediction

Many predictive tasks in recommender systems model from categorical variables. Different from continuous features extracted from images and videos, categorical data is discrete and of multi-field while their dependencies are little known, which brings the problem of heavy computation on a large-scale sparse feature space. Deep learning methods have strong feature extraction capabilities and now have been more and more widely applied to recommender systems, but they do not perform well on discrete data. To tackle these two problems, in this paper we propose Deep Feature Fusion Model(DFFM) over sparse multi-field categorical data. DFFM utilizes categorical features as inputs and applies the Stacked Denoising AutoEncoder to obtain a dense representation. We construct a full feature connection layer and adopt a multi-layer convolution neural network to further extract deeper features and convert rating prediction to a classification problem. The extensive experiments on real world datasets show that our proposed method outperforms other state-of-the-art approaches.