Unobtrusive support definition
Unobtrusive support means that where possible the user should be freed from the necessity of entering into an explicit dialog with all these services and devices. The environment shifts towards the use of implicit interaction, that is, “interactions that may occur without the behest or awareness of the user” [36]. However, not all interactions between user and environment will be implicit. It may not be possible, or it may not be desirable, e.g. because the user does not want to feel a loss of control over certain aspects of his environment. So how does the user achieve the necessary explicit interaction? Will (s)he address every query for information to the specific device or service that ultimately provides the information? Will (s)he give commands to the heating system, the blinds and the room lighting separately? Will each service and each device carry its own interaction interface? Clearly not. Interfaces will come to be developed that abstract from individual services and devices and offer the user access to certain combined functionalities of the system. The interfaces should support the mix- ture of explicit and implicit, and reactive and proactive, interaction required for a successful AmI environment. Finally, AmI environments are inherently multi- user, so the interface needs to be able to understand and engage in addressed multiparty interaction [48]. We argue that Virtual Humans (VHs) are eminently suited to fullfill the role of such interfaces.