Applying Design for Six Sigma to Software and Hardware Systems Book

Foreword    xvii
Preface    xxi
Acknowledgments    xxvii
About the Authors    xxix

Chapter 1: Introduction: History and Overview of DFSS    1
A Brief Historical Perspective on Six Sigma and Design for Six Sigma (DFSS) 1
Historical Perspective on Design for Six Sigma 8
DFSS Example 14
Summary 27

Chapter 2: DFSS Deployment    29
Ideal Scenario for DFSS Deployment 29
Steps Involved in a Successful DFSS Deployment 30
DFSS Deployment: Single Project 45
Minimum Set of Tools, and the “One Tool Syndrome” 47
Goals for DFSS 48
“The DFSS Project was a Success, But . . .” 50
Summary 50

Chapter 3: Governance, Success Metrics, Risks, and Certification    53
DFSS Governance 53
Success Metrics 57
Product Development Risks 58
DFSS Certification 62
Summary 64

Chapter 4: Overview of DFSS Phases    65
DFSS for Projects, Including Software and Hardware 65
DFSS Process Nomenclatures 69
Requirements Phase 73
Architecture Phase 75
Architecture Phase for the Software Aspects 78
Design Phase 78
Integrate Phase 78
Optimize Phase 78
Verify Phase 80
Summary 82

Chapter 5: Portfolio Decision Making and Business Case Risk    83
Position within DFSS Flow 83
Portfolio Decision Making as an Optimization Process 84
Financial Metric 85
Portfolio Decisions and Resource Constraints 89
Goals, Constraints, Considerations, and Distractions 91
Adjusting Portfolio Decisions Based on Existing Commitments and the Organization’s StrategicDirection 92
Summary: Addressing Business Case Risk 94

Chapter 6: Project Schedule Risk    95
Position within DFSS Flow 95
Project Schedule Model 95
The “Fuzzy Front End” and Delays Caused by Changing Requirements 97
Time for First Pass: Critical Path versus Critical Chain 98
Critical Chain/Theory of Constraints Project Management Behaviors 103
Iterations, Qualification, and Release to Product 105
Summary: Addressing Schedule Risk 106

Chapter 7: Gathering Voice of the Customer to Prioritize Technical Requirements    107
Importance and Position within DFSS Flow 107
VOC Purpose and Objectives 110
The VOC Gathering (Interviewing) Team 110
Customer Selection 111
Voices and Images 112
Customer Interview Guide 113
Planning Customer Visits and Interviews 115
Customer Interviews 116
KJ Analysis: Grouping, Structuring and Filtering the VOC 117
Identifying Challenging Customer Requirements (NUDs) 120
Kano Analysis 122
Validation and Prioritization of Customer Requirements 124
Translating Customer Requirements to System Requirements: The System-Level House of Quality 124
Constructing a House of Quality 128
Summary: VOC Gathering—Tying It All Together 134

Chapter 8: Concept Generation and Selection    137
Position within DFSS Flow 137
Concept Generation Approaches 137
Brainstorming and Mind-Mapping 140
TRIZ 141
Alternative Architecture Generation: Hardware and Software 143
Generation of Robust Design Concepts 146
Consideration of Existing Solutions 147
Feasibility Screening 148
Developing Feasible Concepts to Consistent Levels 148
Concept Selection 149
Summary 152
Appendix: Kansei Engineering 152

Chapter 9: Identification of Critical Parameters and FMEA    153
Position within DFSS Flow 153
Definition of a Critical Parameter 153
Considerations from VOB and Constraints 155
Prioritization and Selection of Critical Parameters 157
FMEA 160
Software FMEA Process (Software Systems, Software Subsystems, and Software Components FMEA) 164
Software FMEA Implementation Case Study 169
Considerations of Reliability and Availability 172
Examples of Critical Parameters 174
Summary 176
Appendix: Software FMEA Process Documentation 176

Chapter 10: Requirements Flow-Down    187
Position within DFSS Flow 187
Flow-Down for Hardware and Software Systems 190
Anticipation of Potential Problems: P-Diagrams and DFMEA 193
Target and Spec Limits 197
Measurement System Analysis 198
Capability Analysis 202
Flow-Down or Decomposition 203
Flow-Down Examples 206
Initial Tolerance Allocation 208
Summary 210

Chapter 11: Software DFSS and Agile    211
Measuring the Agile Design 218
Summary 221

Chapter 12: Software Architecture Decisions    223
Software Architecture Decision-Making Process 224
Using Design Heuristics to Make Decisions 227
Using Architecture Tactics to Make Decisions 228
Using DFSS Design Trade-Off Analysis to Make Decisions 230
Using Design Patterns, Simulation, Modeling, and Prototyping for Decisions 234
Summary 235

Chapter 13: Predictive Engineering: Continuous and Discrete Transfer Functions    237
Discrete versus Continuous Critical Parameters 238
Methods for Deriving a Transfer Function for a Discrete Critical Parameter 241
Logistic Regression for Discrete Parameters 242
Methods for Deriving a Transfer Function for a Continuous or Ordinal Critical Parameter 244
Existing or Derived Equation (First Principles Modeling) 245
Modeling within a Spreadsheet, Mathematical Modeling Software, or Simulation Software 246
Empirical Modeling using Historical Data: Regression
Analysis and General Linear Model 247
Empirical Modeling using Design of Experiments 251
Empirical Modeling using Response Surface Methods 256
DOE with Simulators: Design and Analysis of Computer Experiments (DACE) 259
Summary 261

Chapter 14: Predictive Engineering: Optimization and Critical Parameter Flow-Up    263
Critical Parameter Flow-Up: Monte Carlo Simulation 266
Critical Parameter Flow-Up: Generation of System Moments (Root Sum of Squares) 267
Critical Parameter Scorecard 269
Selecting Critical Parameters for Optimization 270
Optimization: Mean and/or Variance 271
Optimization: Robustness through Variance Reduction 273
Multiple Response Optimization 280
Cooptimization of Cpk’s 282
Yield Surface Modeling 283
Case Study: Integrated Alternator Regulator (IAR) IC for Automotive 288
Summary 290

Chapter 15: Predictive Engineering: Software Optimization    293
Multiple Response Optimization in Software 293
Use Case Modeling in Optimization 294
Evaluate the Model 298
Software Mistake Proofing 299
Software Stability 303
Summary 305

Chapter 16: Verification of Design Capability: Hardware    307
Position within DFSS Flow 307
Measurement System Analysis (MSA) 307
Improvements for Inadequate Measurement Systems 310
The Risk of Failures Despite Verification: Test Escapes 313
Determine the Capability 315
Summary 316

Chapter 17: Verification of Reliability and Availability    319
Customer Perspective 319
Availability and Reliability Flow Down 321
Bathtub Curve and Weibull Model 322
Software Reliability 325
Early Life Failures/Infant Mortality 326
Useful Life/Constant Failure Rate 326
Wear Out 327
Detailed Flowchart for Reliability Optimization and Verification 327
Accelerated Life Testing 328
WeiBayes: Zero Failures Obtained from ALT 330
Risk of Failures Despite Verification: Reliability Test Escapes 331
Methods to Improve Reliability and Availability 332
Summary 333
Appendix: Case Studies—Software Reliability, and System Availability (Hardware and Software Availability) 333

Chapter 18: Verification: Software Testing Combined with DFSS Techniques    347
Software Verification Test Strategy Using Six Sigma 350
Controlling Software Test Case Development through Design Patterns 354
Improving Software Verification Testing Using Combinatorial Design Methods 356
Summary 358
Bibliography 359
Glossary of Common Software Testing Terms 359

Chapter 19: Verification of Supply Chain Readiness    363
Position within DFSS Flow 363
Verification that Tolerance Expectations Will Be Met 366
Confidence in Robust Product Assembly (DFMA) 366
Verification of Appropriate and Acceptable Interface Flows 369
Confidence in the Product Launch Schedule 369
Confidence in Meeting On-Time Delivery and Lead-Time Commitments 370
Case Study: Optoelectronic Multichip Module 380
Summary 382

Chapter 20: Summary and Future Directions    385
Future Directions 386

Index 391