1 On the Notions of Abstraction , Consistency , and

One of the most fundamental systems analysis and design principle is that of “abstraction”. Essentially, the purpose of abstraction is to clarify or highlight some features of a problem by concealing others. The set of viewpoints identified in the ODP architecture is merely a pragmatic classification of concerns. A viewpoint leads to a representation of the system with emphasis on a specific set of concerns, and the resulting representation is an abstraction of the system, i.e., a description which recognizes some distinctions that are relevant to the concern and ignores others. The viewpoint models exhibit very subtle concepts with respect to the notion of abstraction and consistency between them. They offer a very powerful structuring paradigm suitable for a design activity. In this paper we explore the notion of abstraction, consistency between viewpoint models, and the role of viewpoint models in the design process framework. The correct understanding of the relationship between viewpoint models and their role in design activity is crucial for the construction of ODP development tools.