Part I Basic Stochastic Optimization Methods
1 Decision/Control Under Stochastic Uncertainty . . . . . . . . . . . 3
1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 Deterministic Substitute Problems: Basic Formulation . . . . . . . . 5
1.2.1 Minimum or Bounded Expected Costs . . . . . . . . . . . . . . . 6
1.2.2 Minimum or Bounded Maximum Costs
(Worst Case) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2 Deterministic Substitute Problems in Optimal Decision
Under Stochastic Uncertainty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.1 Optimum Design Problems with Random Parameters . . . . . . . . 9
2.1.1 Deterministic Substitute Problems in Optimal
Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.1.2 Deterministic Substitute Problems in Quality
Engineering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.2 Basic Properties of Substitute Problems . . . . . . . . . . . . . . . . . . . . 18
2.3 Approximations of Deterministic Substitute Problems
in Optimal Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.3.1 Approximation of the Loss Function . . . . . . . . . . . . . . . . 20
2.3.2 Regression Techniques, Model Fitting, RSM . . . . . . . . . . 22
2.3.3 Taylor Expansion Methods . . . . . . . . . . . . . . . . . . . . . . . . . 26
2.4 Applications to Problems in Quality Engineering . . . . . . . . . . . . 29
2.5 Approximation of Probabilities: Probability Inequalities . . . . . . 30
2.5.1 Bonferroni-Type Inequalities . . . . . . . . . . . . . . . . . . . . . . . . 31
2.5.2 Tschebyscheff-Type Inequalities . . . . . . . . . . . . . . . . . . . . . 32
2.5.3 First Order Reliability Methods (FORM) . . . . . . . . . . . . . 37
Part II Differentiation Methods
3 Differentiation Methods for Probability and Risk Functions 43
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
3.2 Transformation Method: Differentiation by Using an Integral
Transformation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
3.2.1 Representation of the Derivatives by Surface Integrals . . 51
3.3 The Differentiation of Structural Reliabilities . . . . . . . . . . . . . . . 54
3.4 Extensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
3.4.1 More General Response (State) Functions . . . . . . . . . . . . 57
3.5 Computation of Probabilities and its Derivatives
by Asymptotic Expansions of Integral of Laplace Type . . . . . . . 62
3.5.1 Computation of Probabilities of Structural Failure
and Their Derivatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
3.5.2 Numerical Computation of Derivatives
of the Probability Functions Arising in Chance
Constrained Programming . . . . . . . . . . . . . . . . . . . . . . . . . . 66
3.6 Integral Representations of the Probability Function
P(x) and its Derivatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
3.7 Orthogonal Function Series Expansions I: Expansions
in Hermite Functions, Case m = 1 . . . . . . . . . . . . . . . . . . . . . . . . . 75
3.7.1 Integrals over the Basis Functions and the Coefficients
of the Orthogonal Series . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
3.7.2 Estimation/Approximation of P(x) and its Derivatives . 82
3.7.3 The Integrated Square Error (ISE) of Deterministic
Approximations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
3.8 Orthogonal Function Series Expansions II: Expansions
in Hermite Functions, Case m > 1 . . . . . . . . . . . . . . . . . . . . . . . . . 89
3.9 Orthogonal Function Series Expansions III: Expansions
in Trigonometric, Legendre and Laguerre Series . . . . . . . . . . . . . 91
3.9.1 Expansions in Trigonometric and Legendre Series . . . . . . 92
3.9.2 Expansions in Laguerre Series . . . . . . . . . . . . . . . . . . . . . . . 92
Part III Deterministic Descent Directions
4 Deterministic Descent Directions and Efficient Points . . . . . . 95
4.1 Convex Approximation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
4.1.1 Approximative Convex Optimization Problem . . . . . . . . . 99
4.2 Computation of Descent Directions in Case of Normal
Distributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
4.2.1 Descent Directions of Convex Programs . . . . . . . . . . . . . . 105
4.2.2 Solution of the Auxiliary Programs . . . . . . . . . . . . . . . . . . 108
4.3 Efficient Solutions (Points) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
4.3.1 Necessary Optimality Conditions Without Gradients . . . 116
4.3.2 Existence of Feasible Descent Directions
in Non-Efficient Solutions of (4.9a), (4.9b) . . . . . . . . . . . . 117
4.4 Descent Directions in Case of Elliptically Contoured
Distributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
4.5 Construction of Descent Directions by Using Quadratic
Approximations of the Loss Function . . . . . . . . . . . . . . . . . . . . . . 121
Part IV Semi-Stochastic Approximation Methods
5 RSM-Based Stochastic Gradient Procedures . . . . . . . . . . . . . . . 129
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
5.2 Gradient Estimation Using the Response Surface
Methodology (RSM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
5.2.1 The Two Phases of RSM . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
5.2.2 The Mean Square Error of the Gradient Estimator . . . . 138
5.3 Estimation of the Mean Square (Mean Functional) Error . . . . . 142
5.3.1 The Argument Case . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
5.3.2 The Criterial Case . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
5.4 Convergence Behavior of Hybrid Stochastic Approximation
Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
5.4.1 Asymptotically Correct Response Surface Model . . . . . . 148
5.4.2 Biased Response Surface Model . . . . . . . . . . . . . . . . . . . . . 150
5.5 Convergence Rates of Hybrid Stochastic Approximation
Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
5.5.1 Fixed Rate of Stochastic and Deterministic Steps . . . . . . 158
5.5.2 Lower Bounds for the Mean Square Error . . . . . . . . . . . . 169
5.5.3 Decreasing Rate of Stochastic Steps . . . . . . . . . . . . . . . . . 173
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