The integration of task and dialogue modelling in the early stages of user interface design : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Computer Science at Massey University, Palmerston North, New Zealand
In the early stages of the design of graphical user interfaces, models and notations are required for describing user tasks and for describing the structure of the human-computer dialogue to support these tasks. These descriptions should ideally be linked, but in practice task modelling and dialogue modelling are conducted in isolation with differing notations. The research reported in this thesis reviews both task and dialogue modelling and describes how the divide between the two can be bridged via the Lean Cuisine+ notation. Lean Cuisine+ was developed as a semi-formal graphical notation for describing the underlying behaviour of direct manipulation user interfaces (Phillips, 1995). The notation has a significant advantage over other dialogue modelling notations in that it can represent task sequences within the context of the dialogue structure and hence bring dialogue modelling and task modelling together. The research describes how Lean Cuisine+ has been analysed and modified in order to simplify it and to make it more suitable for use with a supporting software tool. There exists a significant gap between user interface design and the design of entire software applications. This is true even for the latest software engineering notation, UML, which has become the de facto industry standard. The thesis reviews UML and reveals its shortcomings regarding support for user interface design. The research suggests a solution for the problem by proposing a method for the early stages of user interface design that uses Lean Cuisine+, in order to combine both task and dialogue modelling, and is constructed to form an integral part of the overall software design process advocated by the authors of UML. The method is applied to two case studies. A prototype Software Environment for Lean Cuisine+ with UML (SELCU) has been developed to enable the construction, storage, editing and printing of Lean Cuisine+ specifications, and to partially support the method. The thesis describes the design, implementation and use of this software support environment. Finally, preliminary work by the author on the automatic generation of Lean Cuisine+ specifications is reported. This shows promise, and has been further developed recently in associated masters-level research in which extensions to SELCU have been implemented.