Design and Safety Assessment of Critical Systems

Design and Safety Assessment of Critical Systems......Page 2
Other titles from Auerbach Publications and CRC Press......Page 3
Design and Safety Assessment of Critical Systems......Page 4
Dedication
......Page 6
Contents......Page 8
Preface......Page 14
Acknowledgments......Page 16
About the Authors......Page 18
1.1 Complex Safety- Critical Systems......Page 20
1.1.1 A Steady Trend toward Complexity......Page 21
1.1.2 An Engineering Challenge......Page 23
1.2 Dealing with Failures: A Short History of Safety Engineering......Page 26
1.3 The Role of Formal Methods......Page 27
1.4 A Case Study: Three Mile Island......Page 28
1.4.1 Pressurized Water Reactors ( PWRs)......Page 29
1.4.2 When Things Go Wrong......Page 32
1.4.3 The Plant Structure......Page 33
1.4.4 Formal Model of a PWR......Page 34
References......Page 36
2.1 Introduction......Page 40
2.2.1 Safety......Page 41
2.2.3 Availability......Page 42
2.2.5 Maintainability......Page 43
2.3 Classification of Faults......Page 44
2.4 Fault Models......Page 45
2.4.1 The Stuck- At Fault Model......Page 46
2.4.4 The Delay Fault Model......Page 48
2.5 Managing Faults......Page 49
2.6 Fault Detection......Page 50
2.6.4 Instruction and Bus Monitoring......Page 51
2.6.7 Watchdog and Health Monitoring......Page 52
2.8 Fault Tolerance......Page 53
2.8.1 Triple Modular Redundancy......Page 54
2.8.2 Dealing with Multiple Failures......Page 55
2.8.3 Dealing with Failures of the Voting Component......Page 56
2.8.4 Dealing with Systematic Failures......Page 57
2.8.5 Fault Tolerance and Fault Detection......Page 58
2.8.7 Emergency Shutdown Systems......Page 59
2.8.8 An Example of Redundant Architecture: Fly- by- Wire Systems......Page 61
2.9 Fault Coverage......Page 62
2.10 Reliability Modeling......Page 63
2.11.1 Series Structures......Page 67
2.11.2 Parallel Structures......Page 69
References......Page 70
3.1 Introduction......Page 72
3.2.1 Fault Tree Analysis ( FTA)......Page 73
3.2.2 Failure Mode and Effects Analysis ( FMEA)......Page 79
3.2.3 Hazard and Operability ( HAZOP) Studies......Page 80
3.2.4 Event Tree Analysis......Page 83
3.3 Risk Analysis......Page 84
3.4.1 Classification of Hazards: Severity......Page 85
3.4.3 Classification of Risks......Page 86
3.4.4 Risk Management and Acceptance......Page 87
References......Page 88
4.1 Introduction......Page 90
4.2 What Makes a System Complex......Page 91
4.3.1 Novelty......Page 92
4.3.4 Geographical Distribution......Page 93
4.3.6 Tools......Page 94
4.4 Measuring the Impact of Complexity......Page 95
4.5 From System to Process......Page 100
4.5.1 Obligations and Benefits......Page 101
4.5.2 Early Assessment......Page 103
4.6 A General Development Framework......Page 105
4.6.1 Phases and Phase Transition......Page 108
4.6.2.1 The Rational Unified Process......Page 109
4.6.2.2 ESA Standards......Page 110
4.6.3 Organization and Sequencing of Phases......Page 111
4.6.4 Workflows......Page 113
4.7.1 Feasibility Study......Page 114
4.7.2 Requirements Analysis......Page 116
4.7.3 Design......Page 117
4.7.5 Hierarchical Design of Systems......Page 118
4.8.1 Acceptance Test Definition......Page 120
4.8.3 Unit Test Definition......Page 122
4.8.4 Test Execution......Page 123
4.9.1 Preliminary Hazard Analysis ( PHA) and Hazard Analysis ( HA)......Page 124
4.9.2 Determination of Assurance Levels......Page 127
4.9.3 Preliminary Safety Assessment ( PSA)......Page 129
4.9.5 Common Cause Analysis ( CCA)......Page 133
4.9.6 Common Cause Analysis and Software......Page 136
4.9.7 Operating and Support Hazard Analysis......Page 137
4.10 Certification Management Workflow......Page 138
4.11 Project Management Workflow......Page 140
4.11.1 Safety Process Definition and Tailoring......Page 142
4.11.3 Other Management Activities......Page 143
4.12 Tool Support......Page 144
4.12.1 Supporting the Development Workflow......Page 146
4.12.2 Supporting the Testing Workflow......Page 148
4.12.4 Supporting the Project Management Workflow......Page 149
4.13 Improving the Process: Maturity Models......Page 151
References......Page 153
5.1 Introduction......Page 158
5.2 Advantages of Formal Methods......Page 159
5.3 Formal Methods in the Development Process......Page 160
5.4 Problems and Limitations......Page 164
5.5 History of Formal Methods......Page 167
5.6.1 Algebraic Specification Languages......Page 168
5.6.2 Model- Based Specification Languages......Page 169
5.6.4 Logic- Based Languages......Page 170
5.6.5 State Transition Systems......Page 172
5.6.6 Temporal Logic......Page 175
5.7.1 Testing and Simulation......Page 180
5.7.2 Theorem Proving......Page 185
5.7.3 Model Checking......Page 186
5.7.4 Using Model Checking for Requirements Validation......Page 191
5.7.5 Using Model Checking for Property Verification......Page 196
5.8 Formal Safety Analysis......Page 199
5.8.1 Fault Injection......Page 201
5.8.2 Fault Models and Model Extension......Page 202
5.8.3 Property Verification......Page 205
5.8.4 Fault Tree Generation......Page 207
5.8.5 FMEA Table Generation......Page 212
5.9 Industrial Applications of Formal Methods......Page 215
5.9.2 The Central Control Function Display Information System ( CDIS)......Page 216
5.9.4 The Mondex Electronic Purse......Page 217
5.9.6 The Traffic Collision Avoidance System ( TCAS)......Page 218
5.9.8 The VIPER Microprocessor......Page 219
5.9.11 The BOS Control System......Page 220
5.9.12 The SLAM Project and the Static Design Verifier......Page 221
5.10 Conclusions and Future Directions......Page 222
References......Page 224
6.1 Certification of Avionic Systems......Page 232
6.2 So Many Standards, So Little Time......Page 236
6.4 Avionics Reference Standards......Page 239
6.5 ARP 4754......Page 241
6.5.1 System Development......Page 242
6.5.3 Assignment of Development Assurance Levels......Page 243
6.5.5 Validation......Page 245
6.6 ARP 4761......Page 246
6.7.1 Document Overview......Page 247
6.7.2 Goals......Page 249
6.7.3 Verification Activities......Page 251
6.7.5 The Role of Tools......Page 252
6.8 The Case for the Safety Case......Page 253
6.9 Formal Methods and Certification......Page 255
References......Page 257
A. 1 Introduction......Page 260
A. 4 Implementation......Page 261
A. 7 Functionalities......Page 262
References......Page 263
B. 1 Introduction......Page 266
B. 3 Architecture......Page 267
B. 4 Implementation......Page 270
B. 7 Functionalities......Page 271
B. 8 Applications......Page 274
References......Page 275
C. 1 BSI, British Standards Institution......Page 278
C. 4 DSTAN, U. K. Defence Standardization......Page 279
C. 7 EUROCONTROL......Page 280
C. 10 FAA, Federal Aviation Administration......Page 281
C. 13 ISO, International Organization for Standardization......Page 282
C. 15 NASA, National Aeronautics and Space Administration......Page 283
C. 16 NRC, U. S. Nuclear Regulatory Commission......Page 284
C. 19 SAE International......Page 285
References......Page 286