Usecaseanalys

Usecaseanalys, often written as use case analysis, is a technique used in requirements engineering and systems design to describe how users interact with a system to achieve goals. It focuses on capturing functional requirements from the perspective of actors and their goals.

Key concepts include actors, use cases, the system boundary, the main success scenario, and extensions or alternate flows. Each use case describes a sequence of interactions that achieves a goal, with preconditions and postconditions that define when the use case can start and what conditions hold at its end.

Process steps include identifying stakeholders and goals, identifying actors and use cases, detailing the main success scenario, modelling extensions and alternate flows, and linking use cases to functional and non-functional requirements. Use case diagrams are commonly used to visualize actors, boundaries, and relationships, often complemented by textual descriptions of each use case.

Outputs include use case descriptions, diagrams, and a traceability matrix linking use cases to requirements, tests, and design elements. These artifacts help stakeholders understand system behavior, prioritize work, and plan validation activities.

Applications and benefits: use case analysis supports requirements elicitation, communication among stakeholders, and scope management in both traditional and agile environments. It is commonly used in software engineering, information systems, and product development to align user needs with system capabilities.

Limitations: the approach can become lengthy and may overemphasize the nominal scenario at the expense of data requirements or non-functional concerns. It may require regular maintenance to stay aligned with evolving requirements.

Example: a use case for "Authenticate user" or "Withdraw cash" illustrates actors, main flow, and potential extensions, such as failed authentication or insufficient funds.