Software Engineering: Requirements Engineering

Requirements Engineering

• Requirements engineering is the process of establishing the services that the customer requires from a system and the constraints under which it operates and is developed.
• It involves several activities, including requirements elicitation and analysis, requirements specification, requirements validation, and requirements management.

Requirements Elicitation and Analysis

• Requirements elicitation and analysis involves identifying and understanding the customer's needs and expectations from the system.
• It involves gathering information from stakeholders, identifying functional and non-functional requirements, and analyzing the feasibility of the requirements.

Requirements Specification

• Requirements specification involves documenting the requirements gathered during elicitation and analysis.
• It involves creating a requirements specification document that outlines the functional and non-functional requirements of the system.

Requirements Validation

• Requirements validation involves checking the requirements specification document for validity, consistency, completeness, and realism.
• It involves verifying that the requirements are correct, unambiguous, and consistent, and that they meet the customer's needs and expectations.

Requirements Management

• Requirements management involves managing changes to the requirements during the system development process.
• It involves tracking changes to the requirements, maintaining a record of changes, and assessing the impact of changes on the system.

System Modeling

• System modeling involves developing models of a system to understand its functionality and behavior.
• It involves creating different types of models, including external, interaction, structural, and behavioral models.

External Perspective

• The external perspective involves modeling the context of the system, including the environment and external interactions.

Interaction Perspective

• The interaction perspective involves modeling the interactions between the system and its environment, or between components of the system.

Structural Perspective

• The structural perspective involves modeling the internal structure of the system, including its components and relationships.

Behavioral Perspective

• The behavioral perspective involves modeling the dynamic behavior of the system, including its responses to events.

Use Cases

• Use cases involve modeling the interactions between actors and the system.
• Each use case represents a discrete task that involves external interaction with the system.
• Use cases are used to identify user requirements and to model the system's functionality.

Use Case Diagrams

• Use case diagrams are used to visualize the relationships between actors, use cases, and the system.
• They involve identifying the actors, use cases, and system components, and modeling their relationships.

Sequence Diagrams

• Sequence diagrams are used to model the interactions between actors and the system over time.
• They involve modeling the sequence of interactions between actors, use cases, and system components.

Include and Extend Relationships

• The include relationship involves breaking out a separate use case that is common across many use cases.
• The extend relationship involves extending a use case to include optional functionality.