Requirements Engineering for Software

Requirements Engineering

for Software

and

_Systems

Second

Edition

Phillip

A.

Laplante

CRC Press

Taylor& FrancisGroup

Boca Raton London NewYork CRC Press isanimprintofthe

Taylor&FrancisCroup,anInforms business

Acknowledgments

xiii

About the Author

xv

Introduction

xvii

1

Introduction

to

_Requirements

_Engineering

1

Motivation 1

What Is

_Requirements

_Engineering?

2

You

_Probably

Don't Do

_{Enough Requirements Engineering}

3

What

Are

_{Requirements?}

3

Requirements

versus Goals 4

Requirements

Level

Classification

4

Requirements

Specifications

Types

6

Functional

_Requirements

6

Nonfunctional

_Requirements

7

Domain

_Requirements

10

Domain

_{Vocabulary Understanding}

11

Requirements

Engineering

Activities 11

Requirements

Elicitation/Discovery

11

Requirements

Analysis

and

_Agreements

12

Requirements

Representation

12

Requirements

Validation 12

Requirements Management

13

Bodies of

_Knowledge

13

Requirements Engineer

17

Requirements Engineering

Paradigms

17

Requirements Engineer

as

Software

_Systems

_Engineer

18

Requirements Engineer

as

Subject

Matter

Expert

18

Requirements Engineer

asArchitect 18

Requirements Engineer

asBusiness Process

Expert

18

Ignorance

asVirtue 18

vi Contents

Customer'sRole

₁₉

Problems with

Traditional

_Requirements

_Engineering

20

Complexity

21

Four Dark Comers 22

Difficulties in

_{Enveloping System}

Behavior 23

Danger

of "All"

in

_{Specifications}

25

Exercises

₂₅

References 26

2

_Preparing

for

_Requirements

Elicitation 29

Product

Mission

Statement

29

Encounter withaCustomer 30

Stakeholders 32

Negative

Stakeholders

33

Stakeholder

Identification 33

Stakeholder

_Questions

33

Stakeholder/Customer Classes

35

Stakeholder

Characteristics

36

Customer Wants and Needs 37

What

Do Customers Want? 37

What Don't

Customers Want? 39

Why

DoCustomers

_Change

Their Minds?

40

Stakeholder Prioritization 41

Communicating

with Customers and Other

Stakeholders

43

Managing Expectations

44

Stakeholder

_Negotiations

45

Uncovering

Stakeholder Goals

46

Exercises

₄₇

References 48

3

_Requirements

Elicitation...

49

Introduction

₄₉

Preparing

for

_Requirements

Elicitation 50

Elicitation

_{Techniques Survey}

51

Brainstorming

51

Card

_Sorting

52

Designer

as

_Apprentice

53

Domain

_Analysis

₅₄

Ethnographic

Observation

₅₅

Goal-Based

_Approaches

56

Group

Work 57 Interviews 58

Introspection

59

Joint

Application Design

(JAD)

60

Laddering

61

Protocol

_Analysis

62

Prototyping

62

Quality

Function

_Deployment

63

Questionnaires/Surveys

66

Repertory

Grids 68 Scenarios 68 Task

_Analysis

69

User Stories

69

Viewpoints

70

Workshops

71

Elicitation

_Summary

71

Which

Combination

of

_Requirements

Elicitation

_Techniques

ShouldBe Used? 72

Prevalence of

_Requirements

Elicitation

_Techniques

72

Eliciting

Hazards

73

Misuse Cases 77

Antimodels

77

Formal Methods

78 Exercises 78 References 79

4

_Writing

the

_Requirements

Document

81

Requirements Agreement

and

_Analysis

81

Requirements

Representation

Approaches

82

IEEE Standard 830-1998 85

IEEE Standard 830 Recommendationson

Representing

Nonfunctional

_Requirements

86 IEEE Standard 830

Recommendations

on

Representing

Functional

_Requirements

87

Operating

System

88 Command

Validation

89

ISO/IEC Standard 25030 90 Use Cases 92

Requirements

Document 93

Users ofa

Requirements

Document 93

Requirements

Document

_Requirements

94

Preferred

_{Writing Style}

. 95

Text Structure

_Analysis

95

Requirement

Format 96 Use

of

_Imperatives

98

viii Contents

Best Practices and Recommendations 100

Exercises 102

References

103

5

_Requirements

Risk

_Management

105 WhatIs

_Requirements

Risk

_Management?

105

Requirements

Validation and Verification 108

Techniques

for

_Requirements

V&V 109

Walkthroughs

110

Inspections

110

Goal-Based

_Requirements

_Analysis

110

Requirements

Understanding

Ill

Validating Requirements

Use Cases 112

Prototyping

113

Requirements

Validation and Verification Matrices

113

Importance

of

Measurement in

_Requirements

Validation

and

Verification

115

Goal/Question/Metric

Analysis

116

Standards for Validation and Verification

116

IEEE Standard 830 117 Correctness 117

Ambiguity

119

Completeness

120

Consistency

120

Ranking

121

Verifiability

121

Modifiability

122

Traceability

122

Example

Validation of

_Requirements

122 NASA

_Requirements

_Testing

124

NASA ARM Tool

124

Imperatives

126

Continuances

126

Directives 127

Options

127

Weak Phrases

127

Incomplete

128

Subjects

131

Specification Depth

131

Readability

Statistics 131

Summary

of NASA Metrics 133

Exercises

136

6

Formal Methods ₁₃₉

Motivation 139

WhatAreFormal Methods? 140

Formal

Methods

Classification 142

A Little

_History

142

Using

Formal Methods

₁₄₃

Examples

143

Formalization

of Train Stationin B 144

Formalization of

_Space

Shuttle

_Flight

Software

_Using

MurO 147 Formalization

of

an

Energy

Management System Using

Category Theory

148

Example: Energy

Management System

149

Requirements

Validation

₁₅₂

Theorem

_Proving

153

Program

Correctness 154 Hoare

_Logic

154 Model

_Checking

₁₅₉

Integrated

Tools ₁₅₉

Objections,

Myths,

and

Limitations

159

Objections

and

_Myths

160

Limitations

of

Formal Methods 162

Bowen and

_Hinchey's

Advice

163

Exercises 164

References 164

7

_Requirements

_{Specification}

and

_Agile

_{Methodologies}

₁₆₇

Introductionto

_{Agile Methodologies}

167

Principles

behind

_Agile

Manifesto

168

Extreme

_Programming

(XP)

170

Scrum ₁₇₁

Requirements Engineering

for

_{Agile Methodologies}

172

General Practices in

_{Agile Methodologies}

173

Example Application

of

_Agile

Software

_Development

₁₇₃

When Is

_Agile

Recommended?

₁₇₅

Agile

Requirements

Best Practices 175

Requirements Engineering

inXP 177

Requirements Engineering

inScrum 177

Writing

UserStories 178

Agile Requirements

Engineering

180

Story-Test-Driven Development

181

Challenges

for

_{Requirements Engineering}

in

_Agile

_{Methodologies}

182

Exercises 183

x Contents

8

Tool

_Support

for

_{Requirements Engineering}

185

Introduction

₁₈₅

Traceability Support

187

Requirements

Linkage Traceability

Matrix 188

Requirements

Source

_Traceability

Matrix 190

Requirements

Stakeholder

_Traceability

Matrix 191

Requirements Management

Tools 192

Open

Source

_{Requirements Engineering}

Tools

193

FreeMind 193

Open

Source

_{Requirements Management}

Tool

_(OSRMT)

196

FitNesse

196

Requirements Engineering

Tool Best Practices 198

Elicitation

_Support

_Technologies

₁₉₈

Using

Wikis for

_Requirements

Elicitation 199

Mobile

_Technologies

199 Virtual Environments 199 Content

_Analysis

200 Metrics 201 Exercises 202 References 202 9

_Requirements

_Management

₂₀₅ Introduction 205

Reconciling

Differences

206

Managing

Divergent

Agendas

206

Consensus

_Building

₂₀₇

Expectation

Revisited: Pascal's

_Wager

209

Global

_Requirements

_Management

211

Antipatterns

in

_{Requirements Management}

212

Environmental

_Antipatterns

213

Divergent

Goals

213 Process Clash 214

Management Antipatterns

214 Metric Abuse 214 Mushroom

_Management

216

Other

_Paradigms

for

_Requirements

_Management

217

Requirements

Management

and

_{Improvisational Comedy}

217

Requirements

Management

as

Scriptwriting

218

Standards for

_Requirements

_Management

₂₁₉

ISO 9001 221

Six

_Sigma

221

Capability Maturity

Model

_{Integrative (CMMI)}

222

ISO/IEEE 12207 224

Usage

of Standards 224

A Case

_Study:

FBI Virtual Case

File

225

Exercises 226

References

227

10 Value

_Engineering

of

_Requirements

229

What,

_Why,

When,

and

How of Value

_Engineering

229

What Is Value

_Engineering?

₂₃₀

When Does Value

_Engineering

Occur? 231

Challenges

to

_Simple

Costversus

Risk

Analysis

232

Estimating

Using

COCOMO and ItsDerivatives 234

COCOMO

₂₃₄

WEBMO ₂₃₅

COSYSMO ₂₃₇

Estimating

Using

Function Points ₂₃₈

Function Point Cost Drivers 239

Feature Points 240

Use Case Points 240

Requirements

FeatureCost

_{Justification}

241

Returnon

Investment

241

Net Present Value 242

Internal Rate of Return 243

Profitability

Index 244

Payback

Period 245

Discounted

_Payback

₂₄₅

Putting

ItAll

_Together

246

Exercises 246

References

₂₄₇

Appendix

A: Software

_Requirements

_{Specification}

foraSmart Home

249

Appendix

B:Software

_Requirements

for

aWastewater

Pumping

Station

WetWell Control

_System

₂₇₅

Glossary.

287