Modeling Usage: Techniques and Tools

Each of the described techniques evolved from the need to gain knowledge about the scope of a system from an external point of view, and to represent this knowledge in a way directly accessible by developers. The above evaluation shows that each technique has a specific stress, thereby neglecting other aspects. Use cases concentrate on the dialog flow, whereas problem scenarios reflect the context of use and the user tasks. User stories emphasize direct discussions about task or user interface issues between developers and users, thus avoiding another medium or representation. Literature mostly treats these techniques in isolation, com-paring them or even confronting them with each other. However, the three aspects (interaction sequences, user tasks, and creating a common understanding by discussion) can form com-plementary parts in usage-oriented modeling. We have good experience with expanding use cases by user tasks and taking the result as the basis for direct discussion. Use scenarios repre-sent this approach.