Requirements Verification & ValidationRequirements Verification & Validation

Jerzy.Nawrocki@put.poznan.plwww.cs.put.poznan.pl/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?