A Case Study in the Specification and Analysis of Design Alternatives for a User Interface

There is considerable interest within the Human Computer Interaction (HCI) community in the use of media spaces to enhance awareness and interaction between workers in offices or other spatially distributed environments. In addition to the technical challenges of providing reliable and efficient audio-visual communication, there are important social questions, in particular how users are able to control access to their personal environments, and how to advise other users about their level of availability. Within AMODEUS-2, an ESPRIT Basic Research Action concerned with the development, transfer and assessment of techniques for modelling human-computer interaction, a prototype media space has been analysed by various user and system oriented modelling techniques. This paper describes how formal specification can be used to express requirements on the interfaces needed to control access and availability in a media space. Beyond its obvious use in clarifying the subtle relationship between these concerns, the paper describes how the speci cation assists in assessing design options originating from other modelling disciplines