“…So far, the most common approach relates the actions of the user (gathered by O-type sensors) with the status of the environment (gathered by C-type sensors) (Gal et al, 2001) (Hagras et al, 2004). We consider, as have other authors (Duman et al, 2008) (Jakkula et al, 2007), that detecting relationships between the user's actions facilitates understanding of the user's behavior, using information about the environment to contextualize such a relationship. Besides facilitating the understanding of the user's behavior, finding these relationships also allows us to use relative time references instead of absolute times.…”