Date of Award


Document Type

Doctoral Thesis

Degree Name

Doctor of Philosophy



First Advisor

Wolfgang Weber

Second Advisor

John O'Brien


This thesis traces the evolution of use cases and use case relationships from the initial suggestion by Jacobson et al. in OOSE until today. This tracing reveals that there are two distinct streams of development, as referred in this thesis to as the “textual world” and the “graphical world”: the textual world being literature concentrating on textual use case properties, i.e. use case writing techniques and use case templates. The second stream that has been developed in parallel with the use case template progression is UML, i.e. Unified Modeling Language, which defines the standard for the use case diagram notation and its semantics. Yet unreported weaknesses, contradictions, and significant problems in both the textual and the graphical world are identified. Furthermore, it is highlighted that the two worlds have been, to date, developing in isolation from each other and, thus, are partially inconsistent with each other; a seamless mapping is not possible, impacting the understanding, and application, of use case models. Even internationally recognised experts in the field obviously do not perceive concepts in a uniform way. Consequently, use case models created in practice are dangerously ambiguous.

This thesis solves the weaknesses and contradictions in both worlds by introducing necessary refinements to the textual use case writing calculus and by fixing fundamental errors in UML’s metamodel. These clarifications enable the alignment and seamless mapping of the graphical use case world to the textual world with respect to the use case relationships Include and Extend, resulting in further UML metamodel modifications.

Altogether, this essentially contributes to connecting the textual and graphical use case worlds that have, to date, existed in isolation. It facilitates an intuitive and unambiguous understanding of UML’s repeatedly discussed Include- and Extend-relationship also textual use case specification. Consequently, this thesis contributes to use case specification and modelling as a tool for functional requirements engineering in practice. Ill

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