Sparse Feature Factorization for Recommender Systems with Knowledge Graphs

TL;DR

KGFlex introduces a sparse feature factorization method for recommender systems that improves training efficiency and personalization by focusing on relevant features, enhancing accuracy, diversity, and reducing bias.

Contribution

The paper proposes KGFlex, a novel sparse factorization approach that models user decisions based on relevant item features, enabling more efficient training and personalized recommendations.

Findings

Improves recommendation accuracy and diversity.

Reduces training complexity by focusing on relevant features.

Demonstrates effectiveness through extensive experiments.

Abstract

Deep Learning and factorization-based collaborative filtering recommendation models have undoubtedly dominated the scene of recommender systems in recent years. However, despite their outstanding performance, these methods require a training time proportional to the size of the embeddings and it further increases when also side information is considered for the computation of the recommendation list. In fact, in these cases we have that with a large number of high-quality features, the resulting models are more complex and difficult to train. This paper addresses this problem by presenting KGFlex: a sparse factorization approach that grants an even greater degree of expressiveness. To achieve this result, KGFlex analyzes the historical data to understand the dimensions the user decisions depend on (e.g., movie direction, musical genre, nationality of book writer). KGFlex represents each item feature as an embedding and it models user-item interactions as a factorized entropy-driven combination of the item attributes relevant to the user. KGFlex facilitates the training process by letting users update only those relevant features on which they base their decisions. In other words, the user-item prediction is mediated by the user's personal view that considers only relevant features. An extensive experimental evaluation shows the approach's effectiveness, considering the recommendation results' accuracy, diversity, and induced bias. The public implementation of KGFlex is available at https://split.to/kgflex.