What is User Requirements?
Comes from the user or other types of stakeholder and expressing a property of a desirable domain that is independent.
What is a System Requirements?
Desirable properties of system introduced into domain
System requriements are specified so that the user requirements are satisfied assuming some domain properties
- The passenger presents the Oyster card to the reader
Satisfication Argument: DSR - What do they stand for?
D: Domain
S: System
R: Requirement
For example: Consider a pedestrian crossing
R: People cross the road safely
S: Specification of the zebra crossing
D: Vehicles will stop
Non-functional requriement
Also known as a quality requirements, exoressed as the desirable qualities of the product
Performance requirements
- Requriement for interactive systems
- Specifies time to do things, throughput rates
- Measure response time or times to take action per period (throughput)
List of Non-functional requirements
- Quality requirements
- Performance
- Look-or-feel
- Device
- Accuracy
- Usability
- Training
- Maintainability
- Recoverability
- Portababiloty
- Reliability
- Security
- Safety
Look-and-feel requirement
- Specifies how end-users will perceive the product
- Measures adherence to standards, colour or designs
- Test observations
Device requirement
- Specifies features, interactive of the product
- Measures adherence to specified standards
- Test using observations, standards compliance rules
Accuracy
- Specifies Precision to be achieved
- Measures using data about object of requirement
- Test ranges, targets
What is Usability?
- Specifies how people interact
- Measures completion times, usage errors, rates
- Tests usability evaluation: HCI“Walk through techniques”
What is Training requiement?
- Specifies the level of tranining
- Measures training duration and outcomes
- Test training course outcomes
What is Maintainability requriement?
- Specifies the level of upgrade of a product
- Measure using time and resource to maintain
- Test using maintenance tasks
What is Recoverability requiement?
Specifies the repair of the product incase of failure
Measures using time and likelihood to recover
Test using simple maintenance and recovery tasks
Portability
- Specifies platforms that the product needs to operate on
- Measure using the names and versions of products and OS
- Test using the usage trials
What is Reliability requirement?
- Specifies the levels of failures of a product
- Measurs using mean-time failures
- Test reliability trials, customer evidence
What is Security requirement?
Specifies which actions in a system are allowed and prohibited
Measures using specified access functions and mean-time
Test security experts
Safety requirement
Specifies how safe a product is
Measures using number/risks of injuries overtime
Test using health/safety compliance techniques
