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Peter Johnson
The classes of models considered includes work and task models, domain models, user interface dialogue models, and models of design processes. Together they address design issues that include analysis, prediction, co-operation, specification, generation, elicitation, communication and exploration.
The first paper by Bekker & Wilson addresses the idea of modelling the design process. A way of comparing design methods is proposed that focuses upon what is being modelled during the design process and how this is used. In this way, comparisons are drawn between design methods that use similar models in different ways, methods that model similar information in different ways, and between methods that use different information and different models.
The second paper by O'Neill is concerned with the development of models within the design process and is focused upon an example of a class of models which characterise the users' current and envisioned work-tasks. He considers how users and designers co-operate in the development of work-task models. The analysis identifies important aspects including where collaboration succeeds and fails, how contributions to the development of the models are made by designers and users and how task-models can be used to elicit and verify design requirements and facilitate user participation.
The paper by Hamilton shifts the focus from analytical to predictive models. The paper describes how usability predictions can be made from domain and task models. Examples of the type of predictions under investigation include: predicting errors caused by changes to the sequential structure of a task, and the presence (or absence) of user interface objects to cue (or fail to cue) the appropriate user actions. Theoretical, empirical and practical aspects of a predictive approach to design are considered.
Smith & O'Neill consider three uses of task models in the implementation of a design and illustrate these uses through discussion of a case study. These include: the definition of workflow in terms of the flow of documents between roles providing a "work agenda" for each user role, the enablement of commands that are required for particular user roles, and the provision of on-line task related help.
The final paper by Elwert provides an example of the class of models concerned with modelling user interfaces. The paper presents an overview of how dialogue models might be related to user interface prototypes on the one hand, and task, user and domain models on the other. Adopting a linguistic view of user interface dialogues, the paper shows how a form of Petri-net can be used to produce dialogue graphs that model dialogues at syntactic and lexical levels and their relations.