Conceptual modeling: an object-oriented approach to requirements specification

This dissertation develops a methodological approach for requirements analysis and specification that utilizes conceptual modeling to incrementally develop and formally specify requirements. The methodology provides a graphical formalism for specification within an object-oriented framework. Classification, generalization, and aggregation are utilized for organizing and identifying the requirements of a system. The modeling strategy integrates conceptual modeling concepts such as hierarchical structures, the role of the environment, and a temporal structure into an object-oriented framework that emphasizes information hiding, data abstraction, and inheritance. This truly unified approach results in requirements that are reliable, modifiable, and easy to understand. Requirements Modeling Language Prime (RML$\sp\prime),$ a formal requirements specification language, was defined to simplify the syntax and extend the underlying semantics of Greenspan's RML. The graphical components of the methodology are formally defined in RML$\sp\prime$ and the results of the methodology are a formal requirements specification expressed in RML$\sp\prime.$ This dissertation addresses the problem of requirements modeling from a knowledge representation perspective. One of the major tasks addressed by this research was to discover what types of knowledge should be expressed during the various stages of requirements acquisition and to determine how to best represent that knowledge. The methodology incorporates this information and guides the analyst through the entire requirements modeling task.