Specifying use case behavior with interaction models

Functional requirements for information systems can be modeled through use cases. Furthermore, use case models have been successfully used in broader contexts than software engineering, as systems engineering. Even if small systems may be modeled as a set of use cases, when large systems requirements are modeled with a plain use case model several difficulties arise. Traditionally, the behavior of use cases has been modeled through textual specifications. In this paper we present an alternate approach based on interaction modeling. The behavior modeling has two variants (one for UML 1.x and one for UML 2.0). We also integrate our behavior modeling with standard use case relationships.