Exploiting the Complementary Relationship between Use Case Models and Activity Diagrams for Developing Quality Requirements Specifications

Use case models and activity diagrams play an important role in the early stages of requirements engineering for systems development. While use case descriptions represent requirements through a sequence of step descriptions in main scenario and alternate scenarios, activity diagrams are often used to connect different use cases and to represent flow of activities corresponding to steps in complex use cases. In the latter type of usage, a complex use case description and the corresponding activity diagram represent a same set of requirements using two different types of artifacts. In such situations, it is necessary to minimize inconsistencies across the models represented by these artifacts and to enhance overall quality of the resulting models. This paper reports the findings from an empirical study aimed at understanding quality dependencies between use case models and activity diagrams, and offers recommendations for developing these artifacts.