Virtual environments (VEs) are often a complex mixture of novel and traditional user interface strategies, and also incorporate real-time dynamics and parallelism. We describe a modelling technique we are developing, which is based on the process algebra CSP. It is shown how VE systems and tasks can be modelled in CSP, and how a prototype system can be generated from the system specification by mapping a subset of CSP signals onto user interface functionality. Keywords: Interaction Design, Process Algebra, Prototyping, Multimodal Interaction, Agent-Oriented Modelling, Virtual Environments, Task Analysis 1 Introduction When designing Virtual Environments (VEs) it seems natural to design them as consisting of multiple `agents', `objects', or processes. For example, MUD and Virtual Reality (VR) systems are usually built out of a large number of concurrent (i.e. parallel and communicating) processes. In our own VE project, the Virtual Music Centre (VMC) [34], a high degree of concurrenc...

. Componentisation of software promises to deliver cost efficiency that has not been achieved through object orientation [19]. PAC [5] is a popular conceptual architecture for structuring user interface software in an object oriented fashion. This paper reports our experience of adapting and refining PAC as a component architecture in the context of consumer electronics, and On-screen Displays in particular. The paper describes a structured scheme for the specification of user interface software components, distinguishing `look' and `feel' specific components, and fostering their modular development and reuse. Keywords. PAC, user interface, software architecture, on-screen display, specification. 1 Introduction This paper discusses a component architecture and a specification scheme for OnScreen Displays (OSD), i.e. graphical user interfaces for consumer electronics devices. The OSD may be supported, e.g., by a `Set-Top Box' which is a device that displays, on an analogue te...

We formally specify the interpretation stage in a dual state space human-computer interaction cycle. This is done by extending / reorganising our previous cognitive architecture. In particular, we focus on shape related aspects of the interpretation process associated with device input prompts. A cash-point example illustrates our approach. Using the SAL model checking environment, we show how the extended cognitive architecture facilitates detection of prompt-shape induced human error.