  The ability of an intelligent environment to connect and adapt to real
internal sates, needs and behaviors' meaning of humans can be made possible by
considering users' emotional states as contextual parameters. In this paper, we
build on enactive psychology and investigate the incorporation of emotions in
pervasive systems. We define emotions, and discuss the coding of emotional
human markers by smart environments. In addition, we compare some existing
works and identify how emotions can be detected and modeled by a pervasive
system in order to enhance its service and response to users. Finally, we
analyze closely one XML-based language for representing and annotating emotions
known as EARL and raise two important issues which pertain to emotion
representation and modeling in XML-based languages.
