Abstract

Current, software architectures for interactive systems assumed that usability is only important when designing the user interface component including the presentation and dialogs. Therefore, most of the architectural models such as MVC and PAC de-coupled the application semantic and the user interface, which was essential for achieving usability. However, this fallacious dichotomy does not address all the usability concerns. For example, semantic feedback leads tight coupling between the application and the user interface, because it has to be analyzed at both the application and the presentation levels. There are two approaches to cope with semantic feedback. We can either place semantic feedback in the presentation or in the application. The two approaches result in much communication between the model and the views. This thesis proposes a new architectural model, called MVCforUsability, for incorporating usability concerns in software architecture. In particular, we discuss the cause/effect relationships that exist between the internal attributes that we generally use to assess the software quality and the usability factors that we use to quantify the usability of the software system. Our investigations propose the following methodological approach: (1) Identify the internal software attributes that affect software usability, such as modularity, functionality, etc. (2) Define the relationship between these internal attributes and external usability factors in terms of typical scenarios. (3) Describe design patterns or improve existing ones for each typical scenario. (4) Discuss how these patterns can be used to improve the MVC model.