A Recommender System for Suggested Sites using Multi-Armed Bandits : Initialising Bandit Contexts by Neural Collaborative Filtering

Abstract: The abundance of information available on the internet necessitates means of quickly finding what is relevant for the individual user. To this end, there has been much research concerning recommender systems and lately specifically methods using deep learning for such systems. This work proposes a Multi-Armed Bandit as a recommender for suggested sites on a browser start page. The system is compared to a pre-existing baseline and does not manage to outperform it in the setting used in controlled experiments. A Neural Collaborative Filtering system is then constructed using a stacked autoencoder and is used to produce user preference vectors that are inserted in the bandit in the hope of improving its performance. Analysis indicates that the bandit solution works better as the number of items grows. The user-informed initialisation used in this work shows a trend of improving over a randomly-initialised bandit, but results are inconclusive. This work also contributes an analysis of the problem domain including which factors impact the performance on the model training for preference vectors, and the performance of the bandit algorithms.