Requirements Analysis Flashcards
What do you do while Requirements Elicitation?
- describe the purpose of the system in a way understood by the customer or user
- make out functional and non functional requirements
What is the product of the Requirements Elicitation?
Requirement Specification
- functional model
- nonfunctional requirements
What do you do in the Analysis Phase?
- create a model of the system, which is complete, consistent, verifiable, definition of the system so that the customer/user is able to understand
What is the product of the of the Analysis phase?
Analysis Model
- dynamic model
- object model
Name at least 3 activities done during requirements elicitation.
• Identify actors: types of users of future system
• Identify scenarios: detailed descriptions of typical functionality provided by future system in
natural language
• Derive use cases: generalise and abstract scenarios to represent functionality of future system
• Refine use cases: detail each use case, describe behaviour of system in presence of exceptions and errors
• Identify relationships among cases: dependencies, better reuse
• Identify nonfunctional requirements: quality aspect of system, not directly related to functionality
What types of requirements elicitation are there?
• Greenfield engineering: development from scratch, no prior system
—-o requirements extracted from client and user, triggered by user needs
• Re-engineering: existing system to reimplement
—-o requirements triggered by new technology
• Interface engineering: service of existing system in new environment
—-o requirements triggered by technology or new market needs
Name some nonfunctional requirements.
- usability
- reliability
- performance
- supportability
- safety
- security
Shortly describe what constraints are.
Constraints are pseudo requirements, where you need to e.g. comply to standards, tools, programming languages…
What is a Scenario?
A Scenario describes interactions between Actor and system, textual/video/pictures
Name at least two types of scenarios.
- As-is scenario: describes current situation, commonly used in re-engineering projects
- Visionary scenario: describes future system, used in all types of projects
- Evaluation scenario: description of user task against actual
- Training scenario: description of step by step instructions to guide novice user through system
What needs to be included into a formalised scenario?
1) Name of action
2) Participating actors
3) Entry conditions
4) Flow of events
5) Exit conditions
6) Special requirements
- > more detail
Which models are created during Analysis?
object model and analysis model
What does the object model do?
It describes the structure of the system using classes, attributes, operations and associations
What does the dynamic model do?
It describes the dynamic (communication) behaviour of the system
how do communication diagrams work?
They model the interaction between multiple classes/objects as flow of messages and describes static structure as well as dynamic behaviour
