Use Case Modeling ECE 621

UC Modeling and QFD Another excellent method of eliciting the functional requirements for a system UC modeling is used mainly in Object- Oriented projects

What will it be used for? For your customers  Customers verify that this is the system they want For you designers  What is the problem exactly, so we can design a solution for it? For your testers  We know exactly what to test for

For your maintenance team  Helps the maintenance team understand the code For you  Acquiring an in demand skill that deals with higher levels of management than coders do  Higher level of management -> more money

What are UC models made of? Two major components  UC Diagram: Presents a visual summary of the services offered by the system to its users  UC Descriptions: A map of scenarios existing between users and the system

Example of a Use Case Rent Video Just a visual summary. Tells you a lot, but not a whole lot.

Use Case Descriptions Diagrams are nice, but they are not enough  How does the customer rent the video?  What does he/she need to do?  Just what happens exactly? Every use case must be accompanied by a textual description Every actor must be accompanied by a textual description

Rent Video UC Description The Customer starts the use case when he/she wants to rent a video. The Customer providers his/her membership card. The system verifies that the Customer does not have any due charger. The system then adds the selected video to that Customer’s account and computes the due date. The Customer’s account is charged.

Use Case modeling issues Inconsistency  UC descriptions do not conform to the diagram  UC descriptions are conflicting Correctness  Wrong information Not Analytical  Premature design decisions Understandability