This ECA carries 70% of the course marks and is a compulsory component. It is to be done individually and not collaboratively with other students.

Question 1

(a) Formulate a use case diagram to depict the MRT application design.
Your use case diagram should show the following:
(i) The actors
(ii) the use cases and their relationships (14 marks)
(b) The following is an extract of the requirements documentation of the MRT application:

“The MRT fares are calculated based on distance traveled. This is a convenient way to pay for train travel. For example, when a commuter has traveled 10 km, he is charged $2.50. However, when a commuter enters and exits from the same station, he is not changed since the distance is 0 km. The fare for a route that includes 2 or more lines are calculated based on the sum of the fare on each line.”

Analyze the above requirements and identify and explain any Two ambiguous, incorrect, incomplete, or inconsistent inadequacies for system design. Note that in your answers, you are not supposed to use imagination to add anything not mentioned in the requirements. Further, do not include general commentaries in your answer.

Question 2

Develop a structural model for the MRT application design, by submitting your answers to the following:

(a) Complete the class description by identifying classes, their attributes, and any hierarchical relationship(s) that would be required for the application.

(b) Appraise the associations among the classes and hierarchical relationship(s) that would be required for the application. Construct the class association diagram in UML as your answer. Ensure that you do not include any derived or redundant association in your diagram.

Question 3

Further analyses, as well as a few walkthroughs, give rise to an updated class diagram, part of which is shown in Figure Q3 below.

Note that this may not be applicable to Question 2 above.

(a) State the role names, X and Y, of the association next to in Figure Q3.

(b) Write an invariant that specifies a station is next to a station that is not itself.