AN EXAMINATION OF THE USE OF DIALOG CHARTS IN SPECIFYING CONCEPTUAL MODELS OF DIALOGS

Abstract

The conceptual design of user interfaces focuses on the specification of the structure of the dialog, independent of any particular implementation approach. While there is common agreement with respect to the importance of this activity, adequate methods and tools to support it are generally unavailable. The Dialog Charts (DCs) yield high level dialog schemas that are abstract enough to support the conceptual design of dialog control structures. They combine dialog concepts with widely accepted design principles, in a uniform diagramming framework. Specifically, the DCs distinguish between the dialog parties, provide for hierarchical decomposition and enforce a structured control flow. A clear set of guiding principles for the conceptual design of dialogs has yet to emerge. In this paper we have elected to focus on the notions of descriptive power and usable power, as they apply to conceptual dialog modeling tools. The conceptual descriptive power of the DCs is informally examined by applying them in a varied set of examples and relating them to their lower level counterparts, namely implementation dialog models like augmented transition networks or context-free grammars. The usable power of the DCs has been examined empirically through a qualitative study of their actual use by system designers. The Dialog Chart models were found by dialog designers to be a useful conceptual design tool, which exhibit the essential attributes identified for conceptual models.