Abstract

Effective user interface is an important component to the success of an interactive system as any of the components that manage the underlying functionality of the system. The development of an effective user interfaces highly depends on the quality of the requirements where the end-user should be actively involved. Therefore, there is a need to accurately capture, interpret, and represent the voice of the end-user when specifying the user interface requirements. The objective of the thesis is to advance the state of the art in bridging the gap between specifying the User Interface Requirements for interactive systems on the one hand and the design and development of it on the other hand. Towards this objective, a software framework called SUCRE (acronym for Scenario and Use-Case based Requirements Engineering) was developed as a part of this thesis work. Use Case Maps (UCMs) that were introduced in the literature were examined and have been enriched with new visual notation for modeling and specifying the user interface requirements. This enriched UCM for User Interface (UCM-UI) model formed a basis for SUCRE. Thus, scenarios and use cases are used as a means to represent the user interface requirements and communicate with end-users. In addition, the thesis explores two other objectives, namely validation of user interface requirements and usability prediction of the intended user interface. SUCRE was used to build operators that validate the consistency, completeness, and precision of the UCM-UI model using heuristics for constructing a formal analysis of the requirements. SUCRE was also used to define a metrics suite to predict usability from scenarios and use cases. This metrics suite includes simple structural measures as well as content-sensitive and task-sensitive metrics. Considering the difficulties in the specification and design of user interfaces, the thesis aimed also to identify the need for a mix of both informal and formal representation in specifying user interface requirements. Therefore, SUCRE was successfully used to bridge the gap between the semi-formal requirement UCM-UI and detailed formal requirements such as UML, LOTOS specifications, and XML.