An Examination of the Use of Dialog Charts in Specifying Conceptual Models of Dialogs

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