Requirements Verification & ValidationRequirements Verification & Validation
[email protected]/jnawrocki/require/
Requirements Engineering & Project ManagementLecture 9
J.Nawrocki, Verification and Validation
XPrince Roles and V&V
Project ManagerAnalyst Architect
Time Time
+ Auditor
J.Nawrocki, Verification and Validation
ArchitectureAim
& ScopeXPrince Artefacts and V&V
Business Model and System Scope
Most Important Use Cases
Architect. Vision & Tools
Requirements Spec.
Mockup
Accept. Tests Frame
Initial Prototype (code + test cases)
GUI Design
A&S Plan
Init. Project Plan
Architect. Plan
Updat. Proj. Plan
Analyst Architect Project Manager
J.Nawrocki, Verification and Validation
Agenda
•Requirements Analysis & Negotiation•Requirements Validation•Capture & Recapture
• Introduction• XPrince Team• Project Lifecycle• The Analyst Role• The Architect Role• The Project
Manager Role• Scaling up• Conclusions
J.Nawrocki, Verification and Validation
Agenda
•Requirements Analysis & Negotiation•Requirements Validation•Capture & Recapture
• Introduction• XPrince Team• Project Lifecycle• The Analyst Role• The Architect Role• The Project
Manager Role• Scaling up• Conclusions
J.Nawrocki, Verification and Validation
Requirements Analysis and Negotiation
The requirements document
Requirements elicitation
Reqs analysis & negotiation
Describing requirements
System modelling
Requirements validation
Requirements management
RE for critical systems
Basic Interm Adv
8
6
54
3
4
4
2
36
-
6
21
3
3
3
3
21
-
1
1-
-
1
2
4
9
J.Nawrocki, Verification and Validation
Basic guidelines
Analysis and negotiation
Define system boundaries
SystemSystem
Person 1
Person 2
Institution
Device
• Process requirements• System requirements• Software requirements
J.Nawrocki, Verification and Validation
Basic guidelines
Analysis and negotiation
Define system boundariesUse checklists for requirements analysis
J.Nawrocki, Verification and Validation
A Checklist Example
• Does a requirement imply the need for some decision-making based on incomplete or unreliable information?
• Will the implementation of a requirement need information which is outside the defined database for the system?
• Is a requirement concerned with the core functionality of the system?
• Is a requirement concerned with the functionality or performance of equipment which is external to the system?
Analysing system’s boundaries
J.Nawrocki, Verification and Validation
Another Checklist Example
a) Correct;b) Unambiguous;c) Complete;d) Consistent;e) Ranked for importance and/or stability;f) Verifiable;g) Modifiable;h) Traceable.
IEEE Std 830-1998
J.Nawrocki, Verification and Validation
A Checklist for Use Cases
Is there a shared clear vision?Are there visible boundaries?Is there clear cast of characters describing end-users?Are all user-level use-cases user-valued transactions?Does each use case have a complete single goal?Is its naming clear and depicting the goal?Are the alternatives an exhaustive set?Are use cases describing just behaviour?Are adornments properly used?Are the conditions detectable?
J.Nawrocki, Verification and Validation
Basic guidelines
Analysis and negotiation
Define system boundariesUse checklists for requirements analysis
Provide software to support negotiationsProvide software to support negotiations
Plan for conflicts and conflict resolution
Prioritise requirements
J.Nawrocki, Verification and Validation
Intermediate guidelines
Analysis and negotiation
Classify requirements using a multidimensional approach
System, User interface, Database, Communications, Security
J.Nawrocki, Verification and Validation
Intermediate guidelines
Analysis and negotiation
Classify requirements using a multidimensional approach
Use interaction matrices to find conflicts and overlaps
System, User interface, Database, Communications, Security
J.Nawrocki, Verification and Validation
Advanced guidelines
Analysis and negotiation
Assess requirements risks
J.Nawrocki, Verification and Validation
Agenda
•Requirements Analysis & Negotiation•Requirements Validation•Capture & Recapture
• Introduction• XPrince Team• Project Lifecycle• The Analyst Role• The Architect Role• The Project
Manager Role• Scaling up• Conclusions
J.Nawrocki, Verification and Validation
Requirements Validation
The requirements document
Requirements elicitation
Reqs analysis & negotiation
Describing requirements
System modelling
Requirements validation
Requirements management
RE for critical systems
Basic Interm Adv
8
6
54
3
4
4
2
36
-
6
21
3
3
3
3
21
-
1
1-
-
1
2
4
9
J.Nawrocki, Verification and Validation
Basic guidelines
Requirements validation
Check that the requirements document meets your standardOrganise formal requirements inspections
J.Nawrocki, Verification and Validation
Artefact
Reviews and Inspection
Review = Analysis of an artefact (e.g. code, document) done by 1 or more people.
Goals of review:Quality assuranceKnowledge dissemination
Review
J.Nawrocki, Verification and Validation
FTR Procedure
Casting
Producer (author)Project ManagerFacilitatorReviewer(s)Recorder
FTR = Formal Technical Review (Formalny przegląd techniczny)
J.Nawrocki, Verification and Validation
FTR Procedure
1. Producer advices the Project Manager + Facilitator that the artefact is ready and sends them a copy.
2. Facilitator contacts all the inspection participants and decides about the date and time of the meeting (the sooner the better). He also sends the artefact to the reviewers.
3. Facilitator writes the agenda for the meeting.4. FTR meeting5. Recorder prepares inspection report and
sends it to the participants. A copy of it goes also to the Project Manager.
J.Nawrocki, Verification and Validation
FTR Meeting
Agenda’s template (I)
Facilitator: Presents the agenda. The participants may propose changes.
Recorder: Collects copies of the preparation forms.
Producer: Presents the artefact. Reviewers may ask questions. Recorder takes notes (issues and defects).
J.Nawrocki, Verification and Validation
FTR Meeting
Agenda’s template (II)
Recorder: Summerizes the issues and defects.
All participants except the producer: Initial secret vote.
Recorder: Collects the votes and presents the result.
Producer: “Last word”All the participants except the producer:
Final secret vote.
J.Nawrocki, Verification and Validation
FTR Meeting
Decision
Acceptance. No modifications are necessary.
Conditional acceptance. There are some defects but additional inspection is not necessary (the Project Manager will check the final version).
Rejection. There are serious defects and an additional inspection is necessary.
J.Nawrocki, Verification and Validation
Agenda
•Requirements Analysis & Negotiation•Requirements Validation•Capture & Recapture
• Introduction• XPrince Team• Project Lifecycle• The Analyst Role• The Architect Role• The Project
Manager Role• Scaling up• Conclusions
J.Nawrocki, Verification and Validation
Capture-Recapture
How many fish are there?
J.Nawrocki, Verification and Validation
Capture-Recapture
1 Catch a sample
J.Nawrocki, Verification and Validation
Capture-Recapture
1 Catch a sample2 Tag them
J.Nawrocki, Verification and Validation
Capture-Recapture
1 Catch a sample2 Tag them3 Release them
J.Nawrocki, Verification and Validation
Capture-Recapture
1 Catch a sample2 Tag them3 Release them4 Catch another group
J.Nawrocki, Verification and Validation
Capture-Recapture
1 Catch a sample2 Tag them3 Release them4 Catch another group5 How many tagged?
J.Nawrocki, Verification and Validation
Capture-Recapture
1 Catch a sample2 Tag them3 Release them4 Catch another group5 How many tagged?
J.Nawrocki, Verification and Validation
Capture-Recapture
1 Catch a sample2 Tag them3 Release them4 Catch another group5 How many tagged?
Total =20 * 30 / 5 =
120
J.Nawrocki, Verification and Validation
Capture-Recapture
A BC
Total defects = A * B / CIf C = 0 ...
Artefact
J.Nawrocki, Verification and Validation
Capture-Recapture
More than 2 reviewers
A B
Most uniqueunique defects found
All others
Total defects = A * B / C
J.Nawrocki, Verification and Validation
Basic guidelines
Requirements validation
Check that the requirements document meets your standardOrganise formal requirements inspections
Use multidisciplinary teams to review requirements
Define validation checklists
J.Nawrocki, Verification and Validation
Intermediate guidelines
Requirements validation
Use prototyping to animate requirementsWrite a draft user manualPropose requirements test cases
J.Nawrocki, Verification and Validation
Advanced guidelines
Requirements validation
Paraphrase system models
J.Nawrocki, Verification and Validation
Questions?
J.Nawrocki, Verification and Validation
Quality assessment
1. What is your general impression? (1 - 6)2. Was it too slow or too fast?3. What important did you learn during the lecture?4. What to improve and how?