Twitter, together with other online social networks, such as Facebook, and Gowalla have begun to collect hundreds of millions of check-ins. Check-in data captures the spatial and temporal information of user movements and interests. To model and analyze the spatio-temporal aspect of check-in data and discover temporal topics and regions, we propose two spatio-temporal topic models: Downstream Spatio-Temporal Topic Model (DSTTM) and Upstream Spatio-Temporal Topic Model (USTTM). Both models can discover temporal topics and regions. We use continuous time to model check-in data, rather than discretized time, avoiding the loss of information through discretization. In order to capture the property that user's interests and activity space will change over time, we propose the USTTM, where users have different region and topic distributions at different times. We conduct experiments on Twitter and Gowalla data sets. In our quantitative analysis, we evaluate the effectiveness of our models by the perplexity, the accuracy of POI recommendations, and user prediction, demonstrating that our models achieve better performance than the state-of-the-art models.
['Yu Liu', 'Martin Ester', 'Bo Hu', 'David W. Cheung']
Spatio-Temporal Topic Models for Check-in Data