1. Task1.1
Performance, reliability, modifiability, availability, security, functionality, reusability, overall
cost, certifiability, reusability
Task1.2
Performance Scenario:
In a very busy day, too many calls come in to the system. At the same time there are 20
calls. A man named Chris has an accident on Downing Road, his leg is broken, he calls 991,
but it seems the system is too busy to answer him. He calls 991 again, 3 minutes later, the
duty staff answers Chris’ calls. The staff records the incident details, such as patient’s name
and location, he inputs the incident details into the system, and the system determines
which ambulance to send. The system informs the ambulance driver to send the ambulance
immediately. 5 minutes later, the ambulance arrives to the location, and takes Chris to the
nearest hospital.
Availability Scenario:
The LAS CAD system is available for 24 hours7 days. Joy has a heart attack at 3:45, his wife
calls 991, since the system is not busy in the morning; the staff answers the call very soon,
the staff records joy’s location and determines the available ambulance to send. The system
informs the ambulance driver to send the ambulance immediately. The ambulance arrives
to the location in 3 minutes, and takes Joy to the nearest hospital.
Security Scenario:
James is a new staff of LAS CAD system; he wants to update a new ambulance’s information.
He accesses to the database, and to add new ambulance information to the database. While
he is doing this, he wants to see his neighbour’s service record. The system doesn’t let him
to see the records.
3. Task1.4
Level 1: Performance, reliability, availability, modifiability
Level 2: Security, functionality, reusability, overall Cost
Level 3: Certifiability, reusability
Ranking is useful, because it shows which quality attributes must be considered more,
designers and developers can focus on these attributes more. Also, more resources and
time are devoted for these attributes.