Resumen:
This paper is focused on the application of the well-known technique of use cases and especially on the activity diagrams used to represent them to enhance the IS requirements management. Based on previous work of the authors on test generation from use cases and recent studies about operation time measurement, this new form of addressing requirements management could offer significant benefits when compared with traditional practices: a) closer integration between functional requirements and usability constraints, b) easier and more profitable way to reuse the effort on the analysis phase and c) better relationship between analysts and users to derive a good quality specification. This paper shows how formal model for an extended activity diagram can be used for double purpose: A risk analysis on one hand and a usability analysis on the other one.