Item Recommendation with Continuous Experience Evolution of Users using Brownian Motion

TL;DR

This paper introduces a novel continuous experience evolution model for recommender systems, using Brownian motion to better capture user maturity and language changes over time, leading to improved prediction accuracy.

Contribution

It proposes an unsupervised model combining Brownian motion and LDA to track smooth user experience and language evolution, surpassing discrete models.

Findings

Model fits data better than discrete baselines

Outperforms state-of-the-art rating prediction methods

Effective in capturing continuous user experience changes

Abstract

Online review communities are dynamic as users join and leave, adopt new vocabulary, and adapt to evolving trends. Recent work has shown that recommender systems benefit from explicit consideration of user experience. However, prior work assumes a fixed number of discrete experience levels, whereas in reality users gain experience and mature continuously over time. This paper presents a new model that captures the continuous evolution of user experience, and the resulting language model in reviews and other posts. Our model is unsupervised and combines principles of Geometric Brownian Motion, Brownian Motion, and Latent Dirichlet Allocation to trace a smooth temporal progression of user experience and language model respectively. We develop practical algorithms for estimating the model parameters from data and for inference with our model (e.g., to recommend items). Extensive experiments with five real-world datasets show that our model not only fits data better than discrete-model baselines, but also outperforms state-of-the-art methods for predicting item ratings.