Dependent on the context they are used in, there are different definitions of the term awareness. Dourish and Bellotti ( 1992) explain awareness as "an understanding of the activities of others, which provides a context for your own activity". This universal definition can be used to derive the aim of awareness as better coordination of activities, which can be reached by information on these activities. Requirements on the design of coordination mechanisms that runs through providing activity information in shared information spaces can be drawn off this definition. Sohlenkamp considers not just information on activities but also information on the state of the system and future options as necessary for emergence of awareness: "[...] awareness means an understanding of the state of a system, including past activities, present status and future options." ( Sohlenkamp, 1998). In contrast, other authors' definitions stress technical aspects such as e.g. access to shared objects "[...] to be aware of the presence of other users and their access to the shared objects" ( Tollmar and Sundbald, 1995) or interpret awareness as a special form of communication "[...] use of implicitly existing information channels with the goal to capture past and present activities [...]" ( Rauschenbach, 1996).
However, in spite of their different meaning these definitions have two aspects in common which are important to the understanding of awareness: first of all awareness refers to a person's knowledge. This implies that reflections focus on the person. There usually is at least one other person involved in the context of this person. In this case awareness can be described as a state of mind of the user. Second, definitions of awareness are concerned with the question how awareness can be "communicated". This way definitions go into the mechanisms and techniques as well as into the necessary information that may help users to get into the state of awareness.
Reflection on these points shows the tight coupling between consciousness as a state of mind and communication. Consciousness and communication do represent different systems, but they are inseparably connected to each other. Without consciousness there is no communication, but without communication a person's consciousness cannot develop either.
To develop a generic model of awareness which can be used as a framework, we will take conventional sender-receiver-communication models and broaden these models by the aspect of awareness. This way we are able to describe the state of an involved person (awareness-"sender" and awareness-"receiver") as well as communication according to the process of information transmission. The model