4.B] How can you develop an effective use case? Develop a UML use case diagram for home security function
Answer:
use cases can be developed by suggests a number of questions12 that should be answered by a use case:
- Who is the primary actor, the secondary actor(s)?
- What are the actor’s goals?
- What preconditions should exist before the story begins?
- What main tasks or functions are performed by the actor?
- What exceptions might be considered as the story is described?
- What variations in the actor’s interaction are possible?
- What system information will the actor acquire, produce, or change?
- Will the actor have to inform the system about changes in the external environment?
- What information does the actor desire from the system?
- Does the actor wish to be informed about unexpected changes?
UML Use Case Diagram for Home Security Function
A UML(Unified Modeling Language) use case diagram provides a visual representation of the interactions between the actors and the system. Below is a description of how this diagram might be structured for the SafeHome system:
Actors:
- Homeowner:
- Interacts with the system to perform various tasks like activating the system, inquiring about sensor status, etc.
- Sensors:
- Provide input to the system regarding the status of doors, windows, and other security zones.
- Monitoring and Response Subsystem:
- Monitors the system and responds to alarms and other events.
Use Cases:
- Enter Password:
- Homeowner enters a password to access system functions.
- Activate System (Stay Mode):
- Homeowner activates the system in stay mode, enabling perimeter sensors only.
- Activate System (Away Mode):
- Homeowner activates the system in away mode, enabling all sensors.
- Inquire About Zone Status:
- Homeowner checks the status of a specific security zone.
- Inquire About Sensor Status:
- Homeowner checks the status of a specific sensor.
- Press Panic Button:
- Homeowner triggers an emergency alarm.
- Deactivate System:
- Homeowner deactivates the system, turning off all sensors.
UML use case diagram for SafeHome home security function:
