Week 4: Requirement Engineering and UML use case diagram

What are Functional requirements?

Functional Requirements define what the system should do (e.g., user login, order processing).

What are Non Functional requirements?

Non-Functional Requirements describe how the system performs (e.g., performance, security, usability).

Use the FURPS model: - F: Functionality - U: Usability - R: Reliability - P: Performance - S: Supportability

What are requirement elicitation and validation techniques?

Elicitation Techniques: - Interviews, surveys - Group sessions - Observation (protocol, participant) - Model-based: goal analysis, use cases - Exploratory: throwaway prototypes

Validation Techniques: - Requirements reviews - Prototyping - Test-case generation

What is a UML use case diagram?

A visual model showing actors, their goals (use cases), and relationships. Helps visualize functionality from the user’s POV.

What questions can use case diagrams answer?

- Who are the actors?

- What are their goals?

- What functions must be supported?

- What information do actors interact with?

- What exceptions and variations exist?

What are the actors and relationships in a use case diagram?

Actors represent roles that interact with the system (e.g., users, other systems). Examples: Customer, Admin, Payment System.

Relationships in UML use case diagrams include:
🔗 Include – One use case always includes another (e.g., “Checkout” includes “Manage Cart”).
➕ Extend – Optional or conditional behavior added to a base use case (e.g., “Guest” extends “Search Books”).
🔁 Dependency – One use case depends on another external service or system (e.g., “Order Tracking” depends on “Shipping Service”).

Name some differences between user stories and use cases

Incremental vs Iterative Development

Incremental development:

Each version adds more completed features.

e.g Agile

Iterative development:

You refine and improve the same thing over and over.

e.g Spiral