Notes on This Document Requirements are specified as a list of goals and non-goals for the project. A link to the UML home page is provided below. UML diagrams are analysis and design tools, and each diagram format can support multiple levels of abstraction. In this document a balance has been struck between using a standard diagram format for requirements elaboration, and maintaining a high level of abstraction. These can be human beings or software systems.
Ellipses represent use cases, i.e. actions or units of functionality in a system.
Lines between actors and use cases indicate a participation of the actor in the use case. Note that no direction or payload of data flow is expressed by the lines between actors and use cases. The document uses UML sequence diagrams to illustrate detailed use case scenarios. Arrows with a solid head represent a message sent from one actor to another. The arrow points from sender to receiver.