A Factored Relevance Model for Contextual Point-of-Interest Recommendation

The challenge of providing personalized and contextually appropriate recommendations to a user is faced in a range of use-cases, e.g., recommendations for movies, places to visit, articles to read etc. In this paper, we focus on one such application, namely that of suggesting 'points of interest' (POIs) to a user given her current location, by leveraging relevant information from her past preferences. An automated contextual recommendation algorithm is likely to work well if it can extract information from the preference history of a user (exploitation) and effectively combine it with information from the user's current context (exploration) to predict an item's 'usefulness' in the new context. To balance this trade-off between exploration and exploitation, we propose a generic unsupervised framework involving a factored relevance model (FRLM), comprising two distinct components, one corresponding to the historical information from past contexts, and the other pertaining to the information from the local context. Our experiments are conducted on the TREC contextual suggestion (TREC-CS) 2016 dataset. The results of our experiments demonstrate the effectiveness of our proposed approach in comparison to a number of standard IR and recommender-based baselines

Scalable models for points-of-interest recommender systems

La recommandation de points d’intérêts (POI) est une composante essentielle des réseaux sociaux géolocalisés. Cette tâche pose de nouveaux défis dûs aux contraintes spécifiques de ces réseaux. Cette thèse étudie de nouvelles solutions au problème de la recommandation personnalisée de POI. Trois contributions sont proposées dans ce travail. La première contribution est un nouveau modèle de factorisation de matrices qui intègre les influences géographique et temporelle. Ce modèle s’appuie sur un traitement spécifique des données. La deuxième contribution est une nouvelle solution au problème dit du feedback implicite. Ce problème correspond à la difficulté à distinguer parmi les POI non visités, les POI dont l’utilisateur ignore l’existence des POI qui ne l’intéressent pas. Enfin la troisième contribution de cette thèse est une méthode pour générer des recommandations à large échelle. Cette approche combine un algorithme de clustering géographique avec l’influence sociale des utilisateurs à différentes échelles de mobilité.The task of points-of-interest (POI) recommendations has become an essential feature in location-based social networks. However it remains a challenging problem because of specific constraints of these networks. In this thesis I investigate new approaches to solve the personalized POI recommendation problem. Three main contributions are proposed in this work. The first contribution is a new matrix factorization model that integrates geographical and temporal influences. This model is based on a specific processing of geographical data. The second contribution is an innovative solution against the implicit feedback problem. This problem corresponds to the difficulty to distinguish among unvisited POI the actual "unknown" from the "negative" ones. Finally the third contribution of this thesis is a new method to generate recommendations with large-scale datasets. In this approach I propose to combine a new geographical clustering algorithm with users’ implicit social influences in order to define local and global mobility scales