Chapter 4 - Requirements Engineering Vocabulary

Vocabulary terms and their definitions related to Requirements Engineering in lexicographical order.

Ambiguity

Words interpreted differently by readers/writers.

Compatibility requirements

Depend on other systems or processes.

Consequential requirements

Emerge from introducing the system.

Domain requirement

Requirements derived from the application domain, may be functional or non-functional.

Enduring requirements

Stable, long-term requirements (e.g., hospitals always need doctors).

Ethnography

Observing people in their real environment to understand requirements.

Form-based specification

Fill-in forms with inputs/outputs/preconditions.

Functional requirement

Services the system should provide.

Happy day scenario

Everything works smoothly.

Mutable requirements

Change due to environmental shifts.

Non-functional requirement

Constraints on services/functions or development (e.g., performance, reliability, location).

Over-flexibility

Same requirement expressed in many ways.

Program Description Language (PDL)

Pseudo-code style operational specification.

Rainy day scenario

Errors, exceptions, or unusual flows.

Requirement

A description/specification of what a system should do or a constraint it must satisfy.

Requirements amalgamation

Several requirements expressed together.

Requirements analysis

Checking requirements for sense and conflicts.

Requirements confusion

Mixing functional and non-functional.

Emergent Requirements

Appear as understanding evolves

Requirements elicitation

Asking stakeholders what they need.

Requirements engineering processes

Processes involved in analyzing and managing requirements.

Requirements management

Handling requirement changes over time.

Requirements validation

Ensuring they solve the user’s problem.

Sequence diagram

Shows sequence of events for use cases.

Software requirements document

Official statement of what developers must build.

Software specification

Detailed design basis for developers.

Structured natural language

Using templates to reduce ambiguity.

System requirements

Structured detailed descriptions as contract.

Use case

Scenario-based interaction description in UML.

User requirements

Natural language + diagrams for customers.

Volatile requirements

Change during development or system use.