Supporting the cognitive process of user interface design with reusable design cases

Abstract

User interface (UI) design is one of the most challenging problem-solving activities that the modern industry faces. The cognitive complexity of design problems and the time pressure due to shortened product life cycles force designers to pursue efficient processes and strategies. For efficiency, UI designers can benefit from their prior design experience that associates target user tasks with available interface means. The practical design activity thus tends to be case-based rather than analytic and linearly deductive. In this paper we develop a framework for a case-based design aid that enables effective reuse of prior design cases in a way that is compatible with practical strategies of designers. In the centre of the framework lies design-case representation at multiple levels of abstraction. The multi-level representation supports the bi-directional and opportunistic strategies of UI designers by enabling easy retrieval of cases at a focused abstraction level and strategy-compatible navigation to related design cases at other levels. A diagrammatic interaction model and a retrieval algorithm based on the model to represent and select design cases are described. It is experimentally verified that the multi-level representation of design cases with the diagrammatic model is useful to UI designers. The overall framework is implemented in a prototype system and the usefulness of the system is shown by examples.