A methodological approach based on machine learning to generate a multimodal use's affective state model in adaptive educational systems - Sergio Salmerón Majadas; Jesús González Boticario (dir. tes.); Olga C. Santos (dir. tes.); Carlos Delgado Kloos (pres.); Beatriz Barros Blanco (secr.); Joao Felipe Dos Santos Sarraipa (voc.) (2018)