Filtering of spontaneous and low intensity emotions in educational contexts - Salmeron-Majadas, S.; Arevalillo-Herráez, M.; Santos, O.C.; Saneiro, M.; Cabestrero, R.; Quirós, P.; Arnau, D.; Boticario, J.G. (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2015)