Preface to the 8 th Edition	6
	Contents	9
	1 Basic Concepts, Quality & Reliability (RAMS) Assurance of Complex Equipment & Systems	16
	1.1 Introduction	16
	1.2 Basic Concepts	17
	1.2.1 Reliability	17
	1.2.2 Failure	18
	1.2.3 Failure Rate, MTTF, MTBF	19
	1.2.4 Maintenance, Maintainability	23
	1.2.5 Logistic Support	23
	1.2.6 Availability	24
	1.2.7 Safety, Risk, Risk Acceptance	24
	1.2.8 Quality	26
	1.2.9 Cost and System Effectiveness	26
	1.2.10 Product Liability	30
	1.2.11 Historical Development	31
	1.3 Basic Tasks & Rules for Quality and Reliability (RAMS) Assurance of Complex Equip. & Systems	32
	1.3.1 Quality and Reliability (RAMS) Assurance Tasks	32
	1.3.2 Basic Quality and Reliability (RAMS) Assurance Rules	34
	1.3.3 Elements of a Quality Assurance System	36
	1.3.4 Motivation and Training	39
	2 Reliability Analysis During the Design Phase	40
	2.1 Introduction	40
	2.2 Predicted Reliability of Equipment and Systems with Simple Structure	43
	2.2.1 Required Function	43
	2.2.2 Reliability Block Diagram	43
	2.2.3 Operating Conditions at Component Level, Stress Factors	48
	2.2.4 Failure Rate of Electronic Components	50
	2.2.5 Reliability of One-Item Structures	54
	2.2.6 Reliability of Series Parallel Structures with Independent Elements	56
	2.2.6.1 Systems without Redundancy (series models)	56
	2.2.6.2 Concept of Redundancy	57
	2.2.6.3 Parallel Models	58
	2.2.6.4 Series Parallel Structures with Independent Elements	60
	2.2.6.5 Majority Redundancy	64
	2.2.7 Part Count Method	66
	2.3 Reliability of Systems with Complex Structure	67
	2.3.1 Key Item Method	67
	2.3.1.1 Bridge Structure	68
	2.3.1.2 Reliability Block Diagram in Which at Least One Element Appears More than Once	69
	2.3.2 Successful Path Method	70
	2.3.3 State Space Method	71
	2.3.4 Boolean Function Method	72
	2.3.5 Parallel Models with Const. Failure Rates & Load Sharing	76
	2.3.6 Elements with more than one Failure Mechanism or one Failure Mode	79
	2.3.7 Basic Considerations on Fault Tolerant Structures	81
	2.4 Reliability Allocation and Optimization	82
	2.5 Mechanical Reliability, Drift Failures	83
	2.6 Failure Modes Analyses	87
	2.7 Reliability Aspects in Design Reviews	92
	3 Qualification Tests for Components and Assemblies	96
	3.1 Basic Selection Criteria for Electronic Components	96
	3.1.1 Environment	97
	3.1.2 Performance Parameters	99
	3.1.3 Technology	99
	3.1.4 Manufacturing Quality	101
	3.1.5 Long-Term Behavior of Performance Parameters	101
	3.1.6 Reliability	101
	3.2 Qualification Tests for Complex Electronic Components	102
	3.2.1 Electrical Test of Complex ICs	103
	3.2.2 Characterization of Complex ICs	105
	3.2.3 Environmental and Special Tests of Complex ICs	107
	3.2.4 Reliability Tests	116
	3.3 Failure Modes, Failure Mechanisms, and Failure Analysis of Electronic Components	116
	3.3.1 Failure Modes of Electronic Components	116
	3.3.2 Failure Mechanisms of Electronic Components	117
	3.3.3 Failure Analysis of Electronic Components	117
	3.3.4 Present VLSI Production-Related Reliability Problems	121
	3.4 Qualification Tests for Electronic Assemblies	123
	4 Maintainability Analysis	127
	4.1 Maintenance, Maintainability	127
	4.2 Maintenance Concept	130
	4.2.1 Equipment and Systems Partitioning	131
	4.2.2 Fault Detection (Recognition) and Localization	131
	4.2.3 User Documentation	133
	4.2.4 Training of Operation and Maintenance Personnel	134
	4.2.5 User Logistic Support	134
	4.3 Maintainability Aspects in Design Reviews	136
	4.4 Predicted Maintainability	136
	4.4.1 Calculation of MTTRS & MDTS	136
	4.4.2 Calculation of Mean Time to Preventive Maintenance	140
	4.5 Basic Models for Spare Parts Provisioning	140
	4.5.1 Centralized Logistic Support, Nonrepairable Spare Parts	140
	4.5.2 Decentralized Logistic Support, Nonrepairable Spare Parts	144
	4.5.3 Repairable Spare Parts	145
	4.6 Maintenance Strategies	149
	4.6.1 Complete renewal at each maintenance action	149
	4.6.2 Block replacement with minimal repair at failure	153
	4.6.3 Further considerations on maintenance strategies	154
	4.7 Basic Cost Considerations	157
	5 Design Guidelines for Reliability, Maintainability, and Software Quality	159
	5.1 Design Guidelines for Reliability	159
	5.1.1 Derating	159
	5.1.2 Cooling	160
	5.1.3 Moisture	162
	5.1.4 Electromagnetic Compatibility, ESD Protection	163
	5.1.5 Components and Assemblies	165
	5.1.5.1 Component Selection	165
	5.1.5.2 Component Use	165
	5.1.5.3 PCB and Assembly Design	166
	5.1.5.4 PCB and Assembly Manufacturing	167
	5.1.5.5 Storage and Transportation	168
	5.1.6 Particular Guidelines for IC Design and Manufacturing	168
	5.2 Design Guidelines for Maintainability	169
	5.2.1 General Guidelines	169
	5.2.2 Testability	170
	5.2.3 Connections, Accessibility, Exchangeability	172
	5.2.4 Adjustment	173
	5.2.5 Human, Ergonomic, and Safety Aspects	173
	5.3 Design Guidelines for Software Quality	174
	5.3.1 Guidelines for Software Defect Prevention	177
	5.3.2 Configuration Management	180
	5.3.3 Guidelines for Software Testing	181
	5.3.4 Software Quality Growth Models	181
	6 Reliability & Availability of Repairable Systems	184
	6.1 Introduction, General Assumptions, Conclusions	184
	6.2 One-Item Structure	190
	6.2.1 One-Item Structure New at Time t=0	191
	6.2.1.1 Reliability Function	191
	6.2.1.2 Point Availability	192
	6.2.1.3 Average Availability	193
	6.2.1.4 Interval Reliability	194
	6.2.1.5 Special Kinds of Availability	195
	6.2.2 One-Item Structure New at t=0 with Const. Failure Rate ?	198
	6.2.3 One-Item Structure with Arbitrary Conditions at t=0	199
	6.2.4 Asymptotic Behavior	200
	6.2.5 Steady-State Behavior	202
	6.3 Systems without Redundancy	204
	6.3.1 Series Structure with Constant Failure and Repair Rates	204
	6.3.2 Series Structure with Constant Failure and Arbitrary Repair Rates	207
	6.3.3 Series Structure with Arbitrary Failure & Repair Rates	208
	6.4 1-out-of-2 Redundancy (Warm, one Repair Crew)	211
	6.4.1 1-out-of-2 Redundancy with Const. Failure & Repair Rates	211
	6.4.2 1-out-of-2 Redundancy with Constant Failure and Arbitrary Repair Rates	219
	6.4.3 1-out-of-2 Redundancy with Constant Failure Rate only in the Reserve State, Arbitrary Repair Rates	222
	6.5 k-out-of-n Redundancy (Warm, Identical Elements, one Repair Crew)	228
	6.5.1 k-out-of-n Redundancy with Const. Failure & Repair Rates	229
	6.5.2 k-out-of-n Redundancy with Constant Failure and Arbitrary Repair Rates	233
	6.6 Simple Series Parallel Structures (one Repair Crew)	235
	6.7 Approximate Expressions for Large Series-Parallel Structures	241
	6.7.1 Introduction	241
	6.7.2 Application to a Practical Example	245
	6.8 Systems with Complex Structure (one Repair Crew)	253
	6.8.1 General Considerations	253
	6.8.2 Preventive Maintenance	255
	6.8.3 Imperfect Switching	258
	6.8.4 Incomplete Coverage	264
	6.8.5 Elements with more than two States or one Failure Mode	272
	6.8.6 Fault Tolerant Reconfigurable Systems	274
	6.8.6.1 Ideal Case	274
	6.8.6.2 Time Censored Reconfiguration (Phased-Mission Systems)	274
	6.8.6.3 Failure Censored Reconfiguration	281
	6.8.6.4 Reward and Frequency / Duration Aspects	285
	6.8.7 Systems with Common Cause Failures	286
	6.8.8 Basic Considerations on Network Reliability	290
	6.8.9 General Procedure for Modeling Complex Systems	292
	6.9 Alternative Investigation Methods	295
	6.9.1 Systems with Totally Independent Elements	295
	6.9.2 Static and Dynamic Fault Trees	295
	6.9.3 Binary Decision Diagrams	298
	6.9.4 Event Trees	301
	6.9.5 Petri Nets	302
	6.9.6 Numerical Reliability and Availability Computation	304
	6.9.6.1 Numerical Computation of System's Reliability and Availability	304
	6.9.6.2 Monte Carlo Simulations	305
	6.9.7 Approximate Expressions for Large, Complex Systems	308
	6.10 Human Reliability	309
	6.11 Risk Management for Repairable Systems	314
	6.11.1 Introduction	314
	6.11.2 Risk Modeling, MTTA, S (t)	316
	6.11.3 Risk Avoidance and Risk Mitigation	324
	7 Statistical Quality Control & Reliability Tests	326
	7.1 Statistical Quality Control	326
	7.1.1 Estimation of a Defective Probability p	327
	7.1.2 Simple Two-sided Sampling Plans for the Demonstration of a Defective Probability p	329
	7.1.2.1 Simple Two-sided Sampling Plan	330
	7.1.2.2 Sequential Test	332
	7.1.3 One-sided Sampling Plans for the Demonstration of a Defective Probability p	333
	7.2 Statistical Reliability (RAMS) Tests	336
	7.2.1 Reliability & Availability Estimation and Demonstration for the Case of a given (fixed) Mission	336
	7.2.2 Availability Estimation & Demonstration for the Case of Continuous Operation (Asymptotic & Steady-state Case)	338
	7.2.2.1 Availability Estimation (Erlangian Failure-Free and / or Repair Times)	338
	7.2.2.2 Availability Demonstration (Erlangian Failure-Free and / or Repair Times)	340
	7.2.2.3 Further Availability Evaluation Methods for Continuous Operation	341
	7.2.3 Estimation & Demonstration of a Constant Failure Rate ? (or of MTBF for the Case MTBF ? 1/?)	343
	7.2.3.1 Estimation of a Constant Failure Rate ? (or of MTBF for MTBF ? 1/?)	345
	7.2.3.2 Simple Two-sided Test for the Demonstration of a Constant Failure Rate ? (or of MTBF for the case MTBF ? 1/?)	347
	7.2.3.3 Simple One-sided Test for the Demonstration of a Constant Failure Rate ? (or of MTBF for the case MTBF ?1/?)	351
	7.3 Estimation and Demonstration of an MTTR	352
	7.3.1 Estimation of an MTTR	352
	7.3.2 Demonstration of an MTTR	354
	7.4 Accelerated Testing	356
	7.5 Goodness-of-fit Tests	361
	7.5.1 Kolmogorov-Smirnov Test	361
	7.5.2 Chi-square Test	365
	7.6 Statistical Analysis of General Reliability Data	368
	7.6.1 General considerations	368
	7.6.2 Tests for Nonhomogeneous Poisson Processes	370
	7.6.3 Trend Tests	372
	7.6.3.1 Tests of an HPP versus an NHPP with increasing intensity	372
	7.6.3.2 Tests of an HPP versus an NHPP with decreasing intensity	375
	7.6.3.3 Heuristic Tests to distinguish between HPP and General Monotonic Trend	376
	7.7 Reliability Growth	378
	8 Quality & Reliability (RAMS) Assurance During the Production Phase (Basic Considerations)	384
	8.1 Basic Activities	384
	8.2 Testing and Screening of Electronic Components	385
	8.2.1 Testing of Electronic Components	385
	8.2.2 Screening of Electronic Components	386
	8.3 Testing and Screening of Electronic Assemblies	389
	8.4 Test and Screening Strategies, Economic Aspects	391
	8.4.1 Basic Considerations	391
	8.4.2 Quality Cost Optimization at Incoming Inspection Level	394
	8.4.3 Procedure to handle first deliveries	399
	A1 Terms and Definitions	400
	A2 Quality and Reliability (RAMS) Standards , Story of Reliability Engineering	416
	A2.1 Introduction	416
	A2.2 General Requirements in the Industrial Field	417
	A2.3 Requirements in the Aerospace, Railway, Defense, and Nuclear Fields	419
	A2.4 A Skillful , Allegorical Story of Reliability	420
	A3 Definition and Realization of Quality & Reliability (RAMS) Requirements	422
	A3.1 Definition of Quality and Reliability (RAMS) Requirements	422
	A3.2 Realization of Quality & Reliability (RAMS) Requirements for Complex Equipment & Systems	424
	A3.3 Elements of a Quality and Reliability (RAMS) Assurance Program	429
	A3.3.1 Project Organization, Planning, and Scheduling	429
	A3.3.2 Quality and Reliability (RAMS) Requirements	430
	A3.3.3 Reliability, Maintainability, and Safety Analyses	430
	A3.3.4 Selection & Qualification of Components, Materials, and Manufacturing Processes	431
	A3.3.5 Software Quality Assurance	431
	A3.3.6 Configuration Management	432
	A3.3.7 Quality Tests	433
	A3.3.8 Quality Data Reporting System	435
	A4 Checklists for Design Reviews	436
	A4.1 System Design Review (Table A3.3, p. 419)	436
	A4.2 Preliminary Design Reviews (Table A3.3 on p. 419)	437
	A4.3 Critical Design Review (System Level, Table A3.3 on p. 419)	440
	A5 Requirements for a Quality Data Reporting System	441
	A6 Basic Probability Theory	444
	A6.1 Field of Events	444
	A6.2 Concept of Probability	446
	A6.3 Conditional Probability, Independence	449
	A6.4 Fundamental Rules of Probability Theory	450
	A6.4.1 Addition Theorem for Mutually Exclusive Events	450
	A6.4.2 Multiplication Theorem for Two Independent Events	451
	A6.4.3 Multiplication Theorem for Arbitrary Events	452
	A6.4.4 Addition Theorem for Arbitrary Events	452
	A6.4.5 Theorem of Total Probability	453
	A6.5 Random Variables, Distribution Functions	454
	A6.6 Numerical Parameters of Random Variables	460
	A6.6.1 Expected Value (Mean)	460
	A6.6.2 Variance	463
	A6.6.3 Modal Value, Quantile, Median	465
	A6.7 Multidimensional Random Variables, Conditional Distributions	465
	A6.8 Numerical Parameters of Random Vectors	467
	A6.8.1 Covariance Matrix, Correlation Coefficient	468
	A6.8.2 Further Properties of Expected Value and Variance	469
	A6.9 Distribution of the Sum of Independent Positive Random Variables and of tmin , tmax	469
	A6.10 Distribution Functions used in Reliability Analysis	472
	A6.10.1 Exponential Distribution	472
	A6.10.2 Weibull Distribution	473
	A6.10.3 Gamma Distribution, Erlangian Distribution, and ?²-Distribution	475
	A6.10.4 Normal Distribution	477
	A6.10.5 Lognormal Distribution	478
	A6.10.6 Uniform Distribution	480
	A6.10.7 Binomial Distribution	480
	A6.10.8 Poisson Distribution	482
	A6.10.9 Geometric Distribution	484
	A6.10.10 Hypergeometric Distribution	485
	A6.11 Limit Theorems	485
	A6.11.1 Laws of Large Numbers	486
	A6.11.2 Central Limit Theorem	487
	A7 Basic Stochastic Processes Theory	491
	A7.1 Introduction	491
	A7.2 Renewal Processes	494
	A7.2.1 Renewal Function, Renewal Density	496
	A7.2.2 Recurrence Times	499
	A7.2.3 Asymptotic Behavior	500
	A7.2.4 Stationary Renewal Processes	502
	A7.2.5 Homogeneous Poisson Processes (HPP)	503
	A7.3 Alternating Renewal Processes	505
	A7.4 Regenerative Processes with a Finite Number of States	509
	A7.5 Markov Processes with a Finite Number of States	511
	A7.5.1 Markov Chains with a Finite Number of States	511
	A7.5.2 Markov Processes with a Finite Number of States	513
	A7.5.3 State Probabilities and Stay Times (Sojourn Times) in a Given Class of States	522
	A7.5.3.1 Method of Differential Equations	522
	A7.5.3.2 Method of Integral Equations	526
	A7.5.3.3 Stationary State and Asymptotic Behavior	527
	A7.5.4 Frequency / Duration and Reward Aspects	529
	A7.5.4.1 Frequency / Duration	529
	A7.5.4.2 Reward	531
	A7.5.5 Birth and Death Process	532
	A7.6 Semi-Markov Processes with a Finite Number of States	536
	A7.7 Semi-regenerative Processes with a Finite Number of States	541
	A7.8 Nonregenerative Stochastic Processes with a Countable Number of States	546
	A7.8.1 General Considerations	546
	A7.8.2 Nonhomogeneous Poisson Processes (NHPP)	547
	A7.8.3 Superimposed Renewal Processes	551
	A7.8.4 Cumulative Processes	552
	A7.8.5 General Point Processes	554
	A8 Basic Mathematical Statistics	556
	A8.1 Empirical Methods	556
	A8.1.1 Empirical Distribution Function	557
	A8.1.2 Empirical Moments and Quantiles	559
	A8.1.3 Further Applications of the Empirical Distribution Function	560
	A8.2 Parameter Estimation	564
	A8.2.1 Point Estimation	564
	A8.2.2 Interval Estimation	569
	A8.2.2.1 Estimation of an Unknown Probability p	569
	A8.2.2.2 Estimation of the Parameter ? for an Exponential Distribution: Fixed Test Duration (Time Censoring), Instantaneous Replacement	573
	A8.2.2.3 Estimation of the Parameter ? for an Exponential Distribution: Fixed Number n of Failures (Failure Censoring), no Replacement	574
	A8.2.2.4 Availability Estimation (Erlangian Failure-Free and / or Repair Times)	576
	A8.3 Testing Statistical Hypotheses	578
	A8.3.1 Testing an Unknown Probability p	579
	A8.3.1.1 Simple Two-sided Sampling Plan	580
	A8.3.1.2 Sequential Test	581
	A8.3.1.3 Simple One-sided Sampling Plan	582
	A8.3.1.4 Availability Demonstration (Erlangian Failure-Free and/or Repair Times)	584
	A8.3.2 Goodness-of-fit Tests for Completely Specified F?(t)	586
	A8.3.3 Goodness-of-fit Tests for a Distribution F?(t) with Unknown Parameters	589
	A9 Tables and Charts	592
	A9.1 Standard Normal Distribution	592
	A9.2 ?²-Distribution (Chi Square Distribution)	593
	A9.3 t-Distribution (Student Distribution)	594
	A9.4 F-Distribution (Fisher Distribution)	595
	A9.5 Table for the Kolmogorov Smirnov Test	596
	A9.6 Gamma Function	597
	A9.7 Laplace Transform	598
	A9.8 Probability Charts	600
	A9.8.1 Lognormal Probability Chart	600
	A9.8.2 Weibull Probability Chart	601
	A9.8.3 Normal Probability Chart	602
	A10 Basic Technological Component's Properties	603
	A11 Problems for Homework	607
	Acronyms	615
	References	616
	Index	642