1. Use Cases:
• Use case— an activity that the system performs, usually in response to a request by
a user. Use cases define functional requirements.
• Use case diagram— a UML model used to graphically show uses cases and their relationships to
2. Activity Diagram:
Activity Diagram– describes user (or system) activities, the person who does each activity, and the
sequential flow of these activities
a. Useful for showing a graphical model of a workflow
b. A UML diagram