More in general my research interests are:

Recommender Systems: collaborative filtering, hybrid recommender systems, privacy protection and collaborative filtering, case-based recommender systems, mobile recommender systems, context-dependent recommendations, group recommendations, implicit feedback, alternative preference models.
User Modeling: distributed UM and cross-technique and cross-domain mediation of UMs, session based (ephemeral) user models, data fusion and user models (in mobile systems).
Adaptive and Conversational Systems: intelligent question selection, cooperative query relaxation, sequential decision making and intelligent recommender agents, supporting user-to-user negotiations, critique-based conversational systems.
Case-Based Reasoning: Structured cases representation (trees and graphs), similarity metrics for complex cases, learning similarity metrics, P2P architectures and case retrieval, case-based planning.
Machine Learning: error correcting output codes, local distance metrics for nearest neighbor classifier, probability based metrics.
Constraint Based Reasoning: distributed and stochastic algorithms, temporal reasoning, object oriented languages and constrains, applications to manufacturing and planning.
eCommerce and Tourism: systems for eDestinations, systems for less developed countries, Digital Business Ecosystems, modeling consumer behavior, semantic based data mediation (Harmonise).