Requirements Engineering

Question 1

Definition: Requirements

Answer 1

descriptions of:

• services provided by the system and
• operational constraints

Question 2

dificulties of RE

Answer 2

• often vague and ambiguous stated requirements
• implicit assumptions
• cooperation of all stakeholders not always given

Question 3

User Requirement

Answer 3

(in natural language and diagrams)

• what services are expected
• operation constraints

Question 4

System Requirements

Answer 4

Precise and detailed specification of the systems
- functions, services
- operational constraints
They are also
- refinements of user requirements and determine the system interface
- recorded as part of the system requirements document

Question 5

Functional Requirements

Answer 5

Functionality that is clearly identifiable and localised in the code

• service provided by the system
• system reaction to inputs
• system behaviour in situations

Question 6

Non-functional Requirements (NFR)

Answer 6

Constraints on the services of functions offered by the system:
- timing constraints
- constraints on the developments process
- standards
Often more critical than individual functional req.

Question 7

How to ensure verifiability of NFRs?

Answer 7

Concretize by:

• making them measurable
• describe what is meant

Question 8

Domain requirements

Answer 8

dervived from the application domain rather from need of the system user
- functional or non-functional

Question 9

Definition: Requirements engineering (RE)

Answer 9

the process of:
- finding out
- analysing
- documenting
- validating
the requirements

Question 10

Flow of RE process

Answer 10

• Feasibility study
• Requirements elicitation and analysis
• Requirements specification
• Requirements validation

Question 11

Feasibility Study

Answer 11

Obtain a founded recommendation whether the requirements engineering and system development process should be started
(Machbarkeits Studie)

Question 12

Requirements discovery: Viewpoint-oriented

Answer 12

interactor viewpoints:
- Person that will directly interact with the System
indirect viewpoints:
- stakeholders that influence the requirements, but will
not directly use the system
domain viewpoints:
- domain characteristics & constraints that influence
the system requirements (e.g. legal regulations)

Question 13

Requirements discovery Techniques

Answer 13

• Viewpoint-oriented (flashcard)
• Interviews: Closed / Open interviews
• Scenarions: squence of interaction with the system
• use cases

Question 14

Requirements Elicitation and Analysis

Answer 14

• Requirements discovery (see flashcard)
• Requirements classification and organization
• Requirements prioritization and negotiation of
  conflicts
• Requirements documentation

Question 15

Requirements validation

Answer 15

Checks for validity, consistency, completeness, realism, verifiability and traceability