Formalization of UML use case diagram-a Z notation based approach

A Unified Modeling Language (UML) use case diagram is a visual tool that provides a way for developers to come to a common understanding with system's end users and domain experts. The behavior of a use case can be specified by describing a flow of events in text for an outsider to understand it easily. The flow of events of a use case is specified in an informal structured text. Therefore, it is not possible to automate the verification of tracking requirements captured in a use case diagram in the design phase. On the other hand, Z is a formal language, which is non-executable, but, a strongly typed specification language. We here propose a structured-expandable format of a use case, which is expressed in Z notation and then represented visually using an Entity-Relationship diagram. Implementation of our approach would bridge the gap between a formal language, which is mathematical and difficult to understand and UML use case diagram that is visual, easy to comprehend and that is used widely to capture requirements. Development of a tool based on this approach will produce a visual representation of a formalized UML use case diagram, from which automated traceability and verification of the design phase can be achieved.