A hierarchical use case model with graphical representation

Use case modelling is gaining increasing interest in computer-based systems engineering, especially in the earliest stages of system development, where requirements are elicited, documented and validated. The paper presents a conceptual framework for use case modelling and a new use case model with graphical representation, including support for different abstraction levels and mechanisms for managing large use case models. Current application of use cases in requirements engineering is discussed, as well as ontological and methodological issues related to use case modelling.