Requirements Writing for System Engineering

409 Pages·2016·9.84 MB·English

by  George Koelsch (auth.)

Requirements
Writing for System
Engineering
—
Project success through realistic
requirements
—
George Koelsch
Requirements
Writing for System
Engineering
George Koelsch
Requirements Writing for System Engineering
George Koelsch
Herndon, Virginia, USA
ISBN-13 (pbk): 978-1-4842-2098-6 ISBN-13 (electronic): 978-1-4842-2099-3
DOI 10.1007/978-1-4842-2099-3
Library of Congress Control Number: 2016956399
Copyright © 2016 by George Koelsch
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Th is is dedicated to the people who work to protect others around the world, men
and women, military and civilian, especially those I served with in Afghanistan
(yes, you too, Blue Devil).
Contents at a Glance
About the Author ............................................................................xxi
Acknowledgments ........................................................................xxiii
■ Part I: The Foundation of Requirements ......................... 1
■ Chapter 1: The Importance of Requirements ..................................3
■ Chapter 2: What Makes a Good Requirement? .............................31
■ Chapter 3: Specialized Language .................................................75
■ Part II: Types of Requirements ..................................... 81
■ Chapter 4: Functional Requirements ............................................83
■ Chapter 5: Nonfunctional Requirements .....................................107
■ Chapter 6: Lists of Items and the Order of
Steps and Data Elements ............................................................151
■ Chapter 7: Data Interfaces and Documents ................................169
■ Chapter 8: Physical Requirements .............................................195
■ Part III: Cradle to Grave Requirements ....................... 209
■ Chapter 9: How to Collect Requirements ....................................211
■ Chapter 10: User Interface Requirements ..................................245
■ Chapter 11: Managing Requirements .........................................257
v
■ CONTENTS AT A GLANCE
■ Part IV: Alternatives to Shall Requirements ............... 273
■ Chapter 12: Supplementing or Replacing
Standard Requirements ..............................................................275
■ Chapter 13: User Stories .............................................................301
■ Chapter 14: Use Cases ................................................................327
■ Chapter 15: Revisiting Requirement Problems and
Their Solutions ...........................................................................349
■ Part V: Appendixes ..................................................... 357
■ Appendix A: Acronyms and Abbreviations .................................359
■ Appendix B: Requirements Documents ......................................365
■ Appendix C: Section 508 Compliance .........................................369
■ Glossary ......................................................................................379
■ Bibliography ...............................................................................389
Index ..............................................................................................393
vi
Contents
About the Author ............................................................................xxi
Acknowledgments ........................................................................xxiii
■ Part I: The Foundation of Requirements ......................... 1
■ Chapter 1: The Importance of Requirements ..................................3
Requirements Conventions Used in the Book .........................................5
Projects Used in This Book ......................................................................6
FBI Record Management Project ..............................................................................7
Radiation Dosimetry Project .....................................................................................7
Basic Defi nitions .....................................................................................8
Defi nitions of Requirements-Related Terms .............................................................8
How Long Does It Take Requirements Engineers to… .............................................9
What Makes a Good RE? .......................................................................11
Personality Traits ....................................................................................................11
Good Communications Skills ..................................................................................17
Summary ................................................................................................................19
Challenges for Writing Effective Requirements .....................................19
Insuffi cient Requirements ......................................................................................19
Scope ......................................................................................................................21
Requirements Creep ...............................................................................................22
Volatility ..................................................................................................................22
Stove-Piped Requirements .....................................................................................23
vii
■ CONTENTS
Users Are Not Sure What They Need .......................................................................24
User Needs Not Satisfi ed ........................................................................................25
Multiple Interpretations Cause Disagreements ......................................................26
Are the Requirements Verifi able? ...........................................................................26
Wasted Time and Resources Building the Wrong Functions ...................................27
Summary ................................................................................................................28
References ............................................................................................29
Exercises ...............................................................................................29
Exercise 1 ...............................................................................................................29
Exercise 2 ...............................................................................................................29
■ Chapter 2: What Makes a Good Requirement? .............................31
Understanding Requirements ................................................................31
The Form of a Requirement ....................................................................................31
Dealing with Negatives in Requirements ................................................................33
Attributes of a Good Requirement .........................................................34
Accurate .................................................................................................................36
Atomic ....................................................................................................................36
Complete ................................................................................................................38
Concise ...................................................................................................................43
Consistent ...............................................................................................................44
Does Not Confl ict with Other Requirements ...........................................................46
Does Not Duplicate Other Requirements ................................................................47
Independent ............................................................................................................48
Prioritized ...............................................................................................................51
Realistic ..................................................................................................................53
Traceable ................................................................................................................55
Unambiguous ..........................................................................................................58
Understandable by Stakeholders ............................................................................64
viii
■ CONTENTS
Unique ....................................................................................................................66
Verifi able .................................................................................................................66
One More Attribute: Modifi able ..............................................................................70
Capability Within a Requirement ...........................................................71
Types of Errors That Can Occur with Requirements ..............................71
Dangerous or Toxic Requirements ..........................................................................72
Extra, Superfl uous Requirements ...........................................................................72
Incomplete Requirements.......................................................................................72
Others .....................................................................................................................73
References ............................................................................................73
Exercises ...............................................................................................73
Exercise 1 ...............................................................................................................73
Exercise 2 ...............................................................................................................74
Exercise 3 ...............................................................................................................74
Exercise 4 ...............................................................................................................74
Exercise 5 ...............................................................................................................74
■ Chapter 3: Specialized Language .................................................75
The Use of Language .............................................................................75
Defi ning Specialized Terms ...................................................................77
Acronyms and Abbreviations .................................................................78
Summary ...............................................................................................80
Exercises ...............................................................................................80
Exercise 1 ...............................................................................................................80
Exercise 2 ...............................................................................................................80
ix
■ CONTENTS
■ Part II: Types of Requirements ..................................... 81
■ Chapter 4: Functional Requirements ............................................83
Understanding Types of Requirements ..................................................83
Types of Functional Requirements ........................................................84
Business Rules .......................................................................................................85
Transactions ...........................................................................................................86
Administrative Functions ........................................................................................88
Authentication ........................................................................................................89
Authorization Levels ...............................................................................................90
Audit Tracking .........................................................................................................91
External Interfaces .................................................................................................92
Certifi cation Requirements .....................................................................................93
Searching and Reporting Requirements .................................................................94
Compliance, Legal, or Regulatory Requirements ....................................................97
Historical Data ........................................................................................................98
Archiving .................................................................................................................99
Structural ..............................................................................................................100
Algorithms ............................................................................................................101
Database ...............................................................................................................101
Power ...................................................................................................................102
Network ................................................................................................................103
Infrastructure ........................................................................................................103
Backup and Recovery ...........................................................................................104
Summary .............................................................................................105
Exercises .............................................................................................105
Exercise 1 .............................................................................................................105
Exercise 2 .............................................................................................................105
x