The 4C Reference Model for Distributed User Interfaces

Distributed User Interfaces (DUIs) are those interfaces whose different parts can be distributed in time and space on different monitors, screens, and computing platforms, depending on several parameters expressing the context of use, such as the user, the computing platform, and the physical environment in which the user is carrying out her interactive task. To understand and classify existing approaches for DUIs and to identify underexplored situations of DUIs, a reference model for DUIs is introduced that examines DUIs according to four "C' dimensions: computation (what is distributed?), communication (when is it distributed?), coordination (who is it distributed?), and con-figuration (from where and to where is the distribution operated?). At the core of this reference model exists the original notion of user interface habitat, that is the place where a particular type of user interface is normally found. According to this notion, it is possible to explore and investigate a wide spectrum of DUIs among which we exemplify several cases coming from our existing research and development of DUIs.