Requirements Flashcards
What are requirements in systems engineering
Needs or wishes that one or more of the stakeholders want the system to fulfill
What do the requirements do
Decide behaviour and nature of system an enterprise needs to undertake
It does not talk about its form
What are functional requirements
A mandatory requirement (level 0)
The base for the system
Gives information for the system without engieneering, design or solutions
Defines what needs to be accomplished
Specifies behaviour between outputs and inputs
Explains what the system needs to be able to do
What are the non-functional requirements (NFR)
PROCID
Performance
Regulatory
Operational
Contraints on the System
Interface
Desirable Non-functional (-ilities)
What is the operational NFR
Usually mandatory
How system handles opertaional demands
Describes what systme does without saying about enigeering
Describes hwo end users will use the system
Can be derived from Concept of Operations
What are the performance NFR
Define how well and under what conditions a function is to be performed
quantitiative
Verifiable individually
What are the regulatory NFR’s
Ensuring compliance with standards like Engineering stadnards, local law, certifiacation authorities, insurance companies, labour agreements, company policy and policies of commerical/religious organisations
What are the constraints NFR’s
Physical ( mass, dimensional, colume)
Design (Compatibility with old models, materials, manufacture)
Enviroment (societal, eco)
Cost and schedule (can only be a trade-off)
What are the desirable non-funcationl NFR’s
Safety
Quality
Reliability
Upgradability
Repairability
Maintability
Sustainability
Hard to quanitify but can increase desirability
What are the interface NFR’s
How the system is requried to interact ith its own system, external systems, environemnt
What wording should be used for essential outcomes
Shall
What wording should be used for an intended outcome (not formally verified, what system will do when complete)
Will
(could be a statement of fact)
What wording should be used for regulatry/legal contraints (has to be met and formally verified)
Must
what is the equation for risk
probability x impact
What is a QFD house
quality function deployment
Indicates quality monitoring
Links requirements to system features
what are the pieces of a QFD house in the horizontal direction
Stakeholder requirements
Rquirement importance (give rating 1-5)
Requirement rating % (importance number/total of importance numbers x100)
relationship matrix (⊙ =9, 0=3, △=1, empty=0)
what are the pieces of a QFD house in the vertical direction
Corelation triangle (++,+,empty,-,–)
Desired change (↑↓0)
System features
relationship matrix
Importance rating (⊙0 △ x importance number for each column)
Importance % (importance rating/total importance ratins x100)
What wording should be used for allowable outcomes
may
What wording should be used for expected outcomes
should
Where do requirements come from
Textural analysis (request for proposal, contract, meeting minutes, interviews with stakeholders/stakeholder reps)
Expanded request for proposal
Requirements captures
Use cases
CONOPS
What is requirement creep and how can you stop it
When stakeholders keep asking for more features after requirements have been set
A paper trail and a well managed set of requirements can push back against creep, statement of requriements
How can you benefit from requirements
Communication
Costs
System definitons/design
What is quality (NFR desirable)
If the system can achieve it’s function
Can improve manufacturing tolerances
Hard to quantify
What is reliability (NFR desirable)
The probability that a system functions correctly during a specific time duration
Quantify liklihood of failure and understand behaviours
What is usability (NFR desirable)
Concerns the ergonomic and human factors involved in the operation of a systems
Human error analysis (HEA)
What is robustness (NFR desirable)
The ability of the system to maintain its performance and deliver the desired function despite changing circumstances
What is flexibility (NFR desirable)
A measure of the number of functions a system can perform
What is evolvability (NFR desirable)
Measures the capacity of the system to evolve and change its purpose
What is extensibility (NFR desirable)
Ability to add new functions over time so that a system can fulfill its original function and a different set of functions
What is adapatability (NFR desirable)
The ability of a system to change itself or its environment to meet its goals or adapt to new requirements
What is agility (NFR desirable)
The ability of a system to repsond rapidly to change
What are logistics (NFR desirables)
ABility to easily transport the system and minimise the quanitity of consumable needed by a system
