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An Application-Oriented Introduction to Essential Optimization Concepts and Best Practices
Optimization is an inherent human tendency that gained new life after the advent of calculus; now, as the world grows increasingly reliant on complex systems, optimization has become both more important and more challenging than ever before. Engineering Optimization provides a practically-focused introduction to modern engineering optimization best practices, covering fundamental analytical and numerical techniques throughout each stage of the optimization process.
Although essential algorithms are explained in detail, the focus lies more in the human function: how to create an appropriate objective function, choose decision variables, identify and incorporate constraints, define convergence, and other critical issues that define the success or failure of an optimization project.
Examples, exercises, and homework throughout reinforce the author’s “do, not study” approach to learning, underscoring the application-oriented discussion that provides a deep, generic understanding of the optimization process that can be applied to any field.
Providing excellent reference for students or professionals, Engineering Optimization:
Clear explanations, explicit equation derivations, and practical examples make this book ideal for use as part of a class or self-study, assuming a basic understanding of statistics, calculus, computer programming, and engineering models. Anyone seeking best practices for “making the best choices” will find value in this introductory resource.
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Veröffentlichungsjahr: 2018
Cover
Title Page
Preface
Introduction
Key Points
Book Aspirations
Organization
Rationale for the Book
Target Audience
Presentation Style
Acknowledgments
Nomenclature
About the Companion Website
Section 1: Introductory Concepts
1 Optimization
1.1 Optimization and Terminology
1.2 Optimization Concepts and Definitions
1.3 Examples
1.4 Terminology Continued
1.5 Optimization Procedure
1.6 Issues That Shape Optimization Procedures
1.7 Opposing Trends
1.8 Uncertainty
1.9 Over‐ and Under‐specification in Linear Equations
1.10 Over‐ and Under‐specification in Optimization
1.11 Test Functions
1.12 Significant Dates in Optimization
1.13 Iterative Procedures
1.14 Takeaway
1.15 Exercises
2 Optimization Application Diversity and Complexity
2.1 Optimization
2.2 Nonlinearity
2.3 Min, Max, Min–Max, Max–Min, …
2.4 Integers and Other Discretization
2.5 Conditionals and Discontinuities: Cliffs Ridges/Valleys
2.6 Procedures, Not Equations
2.7 Static and Dynamic Models
2.8 Path Integrals
2.9 Economic Optimization and Other Nonadditive Cost Functions
2.10 Reliability
2.11 Regression
2.12 Deterministic and Stochastic
2.13 Experimental w.r.t. Modeled OF
2.14 Single and Multiple Optima
2.15 Saddle Points
2.16 Inflections
2.17 Continuum and Discontinuous DVs
2.18 Continuum and Discontinuous Models
2.19 Constraints and Penalty Functions
2.20 Ranks and Categorization: Discontinuous OFs
2.21 Underspecified OFs
2.22 Takeaway
2.23 Exercises
3 Validation
3.1 Introduction
3.2 Validation
3.3 Advice on Becoming Proficient
3.4 Takeaway
3.5 Exercises
Section 2: Univariate Search Techniques
4 Univariate (Single DV) Search Techniques
4.1 Univariate (Single DV)
4.2 Analytical Method of Optimization
4.3 Numerical Iterative Procedures
4.4 Direct Search Approaches
4.5 Perspectives on Univariate Search Methods
4.6 Evaluating Optimizers
4.7 Summary of Techniques
4.8 Takeaway
4.9 Exercises
5 Path Analysis
5.1 Introduction
5.2 Path Examples
5.3 Perspective About Variables
5.4 Path Distance Integral
5.5 Accumulation along a Path
5.6 Slope along a Path
5.7 Parametric Path Notation
5.8 Takeaway
5.9 Exercises
6 Stopping and Convergence Criteria: 1‐D Applications
6.1 Stopping versus Convergence Criteria
6.2 Determining Convergence
6.3 Combinations of Convergence Criteria
6.4 Choosing Convergence Threshold Values
6.5 Precision
6.6 Other Convergence Criteria
6.7 Stopping Criteria to End a Futile Search
6.8 Choices!
6.9 Takeaway
6.10 Exercises
Section 3: Multivariate Search Techniques
7 Multidimension Application Introduction and the Gradient
7.1 Introduction
7.2 Illustration of Surface and Terms
7.3 Some Surface Analysis
7.4 Parametric Notation
7.5 Extension to Higher Dimension
7.6 Takeaway
7.7 Exercises
8 Elementary Gradient‐Based Optimizers
8.1 Introduction
8.2 Cauchy’s Sequential Line Search
8.3 Incremental Steepest Descent
8.4 Takeaway
8.5 Exercises
9 Second‐Order Model‐Based Optimizers
9.1 Introduction
9.2 Successive Quadratic
9.3 Newton–Raphson
9.4 Perspective on CSLS, ISD, SQ, and NR
9.5 Choosing Step Size for Numerical Estimate of Derivatives
9.6 Takeaway
9.7 Exercises
10 Gradient‐Based Optimizer Solutions
10.1 Introduction
10.2 Levenberg–Marquardt (LM)
10.3 Scaled Variables
10.4 Conjugate Gradient (CG)
10.5 Broyden–Fletcher–Goldfarb–Shanno (BFGS)
10.6 Generalized Reduced Gradient (GRG)
10.7 Takeaway
10.8 Exercises
11 Direct Search Techniques
11.1 Introduction
11.2 Cyclic Heuristic Direct (CHD) Search
11.3 Hooke–Jeeves (HJ)
11.4 Compare and Contrast CHD and HJ Features: A Summary
11.5 Nelder–Mead (NM) Simplex: Spendley, Hext, and Himsworth
11.6 Multiplayer Direct Search Algorithms
11.7 Leapfrogging
11.8 Particle Swarm Optimization
11.9 Complex Method (CM)
11.10 A Brief Comparison
11.11 Takeaway
11.12 Exercises
12 Linear Programming
12.1 Introduction
12.2 Visual Representation and Concepts
12.3 Basic LP Procedure
12.4 Canonical LP Statement
12.5 LP Algorithm
12.6 Simplex Tableau
12.7 Takeaway
12.8 Exercises
13 Dynamic Programming
13.1 Introduction
13.2 Conditions
13.3 DP Concept
13.4 Some Calculation Tips
13.5 Takeaway
13.6 Exercises
14 Genetic Algorithms and Evolutionary Computation
14.1 Introduction
14.2 GA Procedures
14.3 Fitness of Selection
14.4 Takeaway
14.5 Exercises
15 Intuitive Optimization
15.1 Introduction
15.2 Levels
15.3 Takeaway
15.4 Exercises
16 Surface Analysis II
16.1 Introduction
16.2 Maximize Is Equivalent to Minimize the Negative
16.3 Scaling by a Positive Number Does Not Change DV
16.4 Scaled and Translated OFs Do Not Change DV
16.5 Monotonic Function Transformation Does Not Change DV
16.6 Impact on Search Path or NOFE
16.7 Inequality Constraints
16.8 Transforming DVs
16.9 Takeaway
16.10 Exercises
17 Convergence Criteria 2
17.1 Introduction
17.2 Defining an Iteration
17.3 Criteria for Single TS Deterministic Procedures
17.4 Criteria for Multiplayer Deterministic Procedures
17.5 Stochastic Applications
17.6 Miscellaneous Observations
17.7 Takeaway
17.8 Exercises
18 Enhancements to Optimizers
18.1 Introduction
18.2 Criteria for Replicate Trials
18.3 Quasi‐Newton
18.4 Coarse–Fine Sequence
18.5 Number of Players
18.6 Search Range Adjustment
18.7 Adjustment of Optimizer Coefficient Values or Options in Process
18.8 Initialization Range
18.9 OF and DV Transformations
18.10 Takeaway
18.11 Exercises
Section 4: Developing Your Application Statements
19 Scaled Variables and Dimensional Consistency
19.1 Introduction
19.2 A Scaled Variable Approach
19.3 Sampling of Issues with Primitive Variables
19.4 Linear Scaling Options
19.5 Nonlinear Scaling
19.6 Takeaway
19.7 Exercises
20 Economic Optimization
20.1 Introduction
20.2 Annual Cash Flow
20.3 Including Risk as an Annual Expense
20.4 Capital
20.5 Combining Capital and Nominal Annual Cash Flow
20.6 Combining Time Value and Schedule of Capital and Annual Cash Flow
20.7 Present Value
20.8 Including Uncertainty
20.9 Takeaway
20.10 Exercises
21 Multiple OF and Constraint Applications
21.1 Introduction
21.2 Solution 1: Additive Combinations of the Functions
21.3 Solution 2: Nonadditive OF Combinations
21.4 Solution 3: Pareto Optimal
21.5 Takeaway
21.6 Exercises
22 Constraints
22.1 Introduction
22.2 Equality Constraints
22.3 Inequality Constraints
22.4 Constraints: Pass/Fail Categories
22.5 Hard Constraints Can Block Progress
22.6 Advice
22.7 Constraint‐Equivalent Features
22.8 Takeaway
22.9 Exercises
23 Multiple Optima
23.1 Introduction
23.2 Solution: Multiple Starts
23.3 Other Options
23.4 Takeaway
23.5 Exercises
24 Stochastic Objective Functions
24.1 Introduction
24.2 Method Summary for Optimizing Stochastic Functions
24.3 What Value to Report?
24.4 Application Examples
24.5 Takeaway
24.6 Exercises
25 Effects of Uncertainty
25.1 Introduction
25.2 Sources of Error and Uncertainty
25.3 Significant Digits
25.4 Estimating Uncertainty on Values
25.5 Propagating Uncertainty on DV Values
25.6 Implicit Relations
25.7 Estimating Uncertainty in DV and OF
25.8 Takeaway
25.9 Exercises
26 Optimization of Probable Outcomes and Distribution Characteristics
26.1 Introduction
26.2 The Concept of Modeling Uncertainty
26.3 Stochastic Approach
26.4 Takeaway
26.5 Exercises
27 Discrete and Integer Variables
27.1 Introduction
27.2 Optimization Solutions
27.3 Convergence
27.4 Takeaway
27.5 Exercises
28 Class Variables
28.1 Introduction
28.2 The Random Keys Method: Sequence
28.3 The Random Keys Method: Dichotomous Variables
28.4 Comments
28.5 Takeaway
28.6 Exercises
29 Regression
29.1 Introduction
29.2 Perspective
29.3 Least Squares Regression: Traditional View on Linear Model Parameters
29.4 Models Nonlinear in DV
29.5 Maximum Likelihood
29.6 Convergence Criterion
29.7 Model Order or Complexity
29.8 Bootstrapping to Reveal Model Uncertainty
29.9 Perspective
29.10 Takeaway
29.11 Exercises
Section 5: Perspective on Many Topics
30 Perspective
30.1 Introduction
30.2 Classifications
30.3 Elements Associated with Optimization
30.4 Root Finding Is Not Optimization
30.5 Desired Engineering Attributes
30.6 Overview of Optimizers and Attributes
30.7 Choices
30.8 Variable Classifications
30.9 Constraints
30.10 Takeaway
30.11 Exercises
31 Response Surface Aberrations
31.1 Introduction
31.2 Cliffs (Vertical Walls)
31.3 Sharp Valleys (or Ridges)
31.4 Striations
31.5 Level Spots (Functions 1, 27, 73, 84)
31.6 Hard‐to‐Find Optimum
31.7 Infeasible Calculations
31.8 Uniform Minimum
31.9 Noise: Stochastic Response
31.10 Multiple Optima
31.11 Takeaway
31.12 Exercises
32 Identifying the Models, OF, DV, Convergence Criteria, and Constraints
32.1 Introduction
32.2 Evaluate the Results
32.3 Takeaway
32.4 Exercises
33 Evaluating Optimizers
33.1 Introduction
33.2 Challenges to Optimizers
33.3 Stakeholders
33.4 Metrics of Optimizer Performance
33.5 Designing an Experimental Test
33.6 Takeaway
33.7 Exercises
34 Troubleshooting Optimizers
34.1 Introduction
34.2 DV Values Do Not Change
34.3 Multiple DV Values for the Same OF Value
34.4 EXE Error
34.5 Extreme Values
34.6 DV Is Dependent on Convergence Threshold
34.7 OF Is Irreproducible
34.8 Concern over Results
34.9 CDF Features
34.10 Parameter Correlation
34.11 Multiple Equivalent Solutions
34.12 Takeaway
34.13 Exercises
Section 6: Analysis of Leapfrogging Optimization
35 Analysis of Leapfrogging
35.1 Introduction
35.2 Balance in an Optimizer
35.3 Number of Initializations to be Confident That the Best Will Draw All Others to the Global Optimum
35.4 Leap‐To Window Amplification Analysis
35.5 Analysis of
α
and
M
to Prevent Convergence on the Side of a Hill
35.6 Analysis of
α
and
M
to Minimize NOFE
35.7 Probability Distribution of Leap‐Overs
35.8 Takeaway
35.9 Exercises
Section 7: Case Studies
36 Case Study 1
36.1 Process and Analysis
36.2 Exercises
37 Case Study 2
37.1 The Process and Analysis
37.2 Exercises
38 Case Study 3
38.1 The Process and Analysis
38.2 Exercises
39 Case Study 4
39.1 The Process and Analysis
39.2 Pre‐Assignment Note
39.3 Exercises
40 Case Study 5
40.1 The Process and Analysis
40.2 Exercises
41 Case Study 6
41.1 Description and Analysis
41.2 Exercises
42 Case Study 7
42.1 Concepts and Analysis
42.2 Exercises
43 Case Study 8
43.1 Description and Analysis
43.2 Exercises
44 Case Study 9
44.1 Description and Analysis
44.2 Exercises
45 Case Study 10
45.1 Description and Analysis
45.2 Exercises
Section 8: Appendices
Appendix A: Mathematical Concepts and Procedures
A.1 Representation of Relations
A.2 Taylor Series Expansion (Single Variable)
A.3 Taylor Series Expansion (Multiple Variable)
A.4 Evaluating First Derivatives at
x
0
A.5 Partial Derivatives: First Order
A.6 Partial Derivatives: Second Order
A.7 Linear Algebra Notations
A.8 Algebra and Assignment Statements
Appendix B: Root Finding
B.1 Introduction
B.2 Interval Halving: Bisection Method
B.3 Newton’s: Secant Version
B.4 Which to Choose?
Appendix C: Gaussian Elimination
C.1 Linear Equation Sets
C.2 Gaussian Elimination
C.3 Pivoting
C.4 Code in VBA
Appendix D: Steady‐State Identification in Noisy Signals
D.1 Introduction
D.2 Conceptual Model
D.3 Method Equations
D.4 Coefficient, Threshold, and Sample Frequency Values
D.5 Type‐I Error
D.6 Type‐II Error
D.7 Alternate Type‐I Error
D.8 Alternate Array Method
D.9 SSID and TSID VBA Code
Appendix E: Optimization Challenge Problems (2‐D and Single OF)
E.1 Introduction
E.2 Challenges for Optimizers
E.3 Test Functions
E.4 Other Test Function Sources
Appendix F: Brief on VBA Programming
F.1 Introduction
F.2 To Start
F.3 General
F.4 I/O to Excel Cells
F.5 Variable Types and Declarations
F.6 Operations
F.7 Loops
F.8 Conditionals
F.9 Debugging
F.10 Run Buttons (Commands)
F.11 Objects and Properties
F.12 Keystroke Macros
F.13 External File I/O
F.14 Solver Add‐In
F.15 Calling Solver from VBA
Section 9: References and Index
References and Additional Resources
Books on Optimization
Books on Probability and Statistics
Books on Simulation
Specific Techniques
Selected Landmark Papers
Selected Websites Resources
Index
End User License Agreement
Chapter 03
Table 3.1 Bloom’s taxonomy of cognitive skill.
Chapter 11
Table 11.1 Optimizer results on Function 11.
Chapter 14
Table 14.1 Example of two chromosomes.
Table 14.2 Gene sequencing in two individuals.
Table 14.3 Random selection of parent genes makes the child chromosome.
Table 14.4 Illustration of several types of mutations.
Chapter 19
Table 19.1 Illustration of disparate ranges.
Chapter 20
Table 20.1 Risk of failure.
Table 20.2 Present value example.
Chapter 21
Table 21.1 A Pareto optimal comparison of optimizers.
Chapter 23
Table 23.1 Probability of at least one success in
N
trials.
Table 23.2 Possible conditional probabilities.
Table 23.3 Snyman and Fatti
p
values w.r.t.
r
and
n.
Table 23.4 Probability as a ratio of
r
to
n.
Table 23.5
p
global using
n
and
f
and best‐of‐
N
formula.
Chapter 24
Table 24.1 Experimental comparison—rms values of cluster scaled DV range/average number of function evaluations to converge.
Chapter 29
Table 29.1 Data for Exercise 16.
Table 29.2 Data for Exercise 22.
Chapter 32
Table 32.1 Data for Exercise 10.
Table 32.2 A confusion matrix for Exercise 11.
Chapter 33
Table 33.1 PNOFE data for the optimizer comparison.
Chapter 35
Table 35.1 Number of initial players for test functions—from Equation (35.9).
Table 35.2 Comparison of PNOFE of original and improved initialization algorithms.
Chapter 36
Table 36.1 Cash flow table for PV calculation.
Table 36.2 How various economic indices trend with choice of which to minimize.
Chapter 43
Table 43.1 Value of givens for the liquid–vapor tank separator application.
Chapter 01
Figure 1.1 Illustrating a function with a maximum.
Figure 1.2 Regression illustration.
Figure 1.3 Equivalency of maximizing and minimizing the negative: (a) seeking the maximum and (b) seeking the minimum of the negative of the function.
Figure 1.4 Analysis of a rectangle.
Figure 1.5 A function with one minimum.
Figure 1.6 Mental construct of a battery in a resistance circuit.
Figure 1.7 Illustration of a function with a single maximum.
Figure 1.8 Illustrating a monotonic OF response to a DV.
Figure 1.9 Illustrating a dual OF response to a DV—multiplicative functionality.
Figure 1.10 Illustrating a dual OF response to a DV—additive functionality.
Figure 1.11 Illustrating a monotonic OF response to a DV—additive functionality.
Figure 1.12 Illustrating an under‐specified application.
Figure 1.13 Illustrating a balanced application.
Figure 1.14 Illustrating an over‐specified application.
Chapter 02
Figure 2.1 A box.
Figure 2.2 Illustrating striations.
Figure 2.3 Illustration of sharp valleys.
Figure 2.4 Illustration of a stochastic function.
Figure 2.5 Illustrations of multiple optima: (a) discontinuous, (b) continuum.
Figure 2.6 Illustration of a saddle point.
Figure 2.7 (a) A function and (b) its derivative.
Figure 2.8 Illustration of a penalty function, a soft constraint.
Chapter 03
Figure 3.1 Illustration of two functions to be added.
Chapter 04
Figure 4.1 (a) A continuous function of a single variable and (b) its derivative.
Figure 4.2 A secant method for root finding on a derivative.
Figure 4.3 Illustration of the quadratic surrogate model.
Figure 4.4 Bisection search stage 1—marching.
Figure 4.5 Illustration of the bisection method.
Figure 4.6 Golden Section method.
Figure 4.7 Golden Section apportionment.
Figure 4.8 Squaring a rectangle.
Figure 4.9 Illustration of the beginning of a heuristic direct search.
Figure 4.10 Illustration of a heuristic direct search: (a) unconstrained and (b) constrained.
Figure 4.11 Representation of the quandary over flat spots in the OF.
Figure 4.12 Illustration of leapfrogging: (a) first leap and (b) second and third leaps.
Figure 4.13 Illustration of an overstep when the second derivative has a low value.
Figure 4.14 Illustration of an understep when the derivative asymptotically approaches zero.
Figure 4.15 Illustration of ill‐behaved OF responses: (a) stochastic and (b) pinhole.
Figure 4.16 Illustration of (a) function discontinuity and (b) slope discontinuity.
Figure 4.17 Two difficult optimization cases: (a) minimum overstepped and (b) causes divergence in second‐order methods.
Figure 4.18 Illustration for Exercise 7.
Figure 4.19 Illustration for Exercises 8 and 9.
Chapter 05
Figure 5.1 Getting from
A
to
B
.
Figure 5.2 Coast into space game.
Figure 5.3 Best speed profile from
A
to
B
.
Figure 5.4 Path distance: (a) overall, (b) Pythagorean, and (c) tangent.
Figure 5.5 Illustrating slope along a path.
Chapter 06
Figure 6.1 Illustration of convergence criterion on OF threshold.
Figure 6.2 Illustration of issues with convergence on Δ
f.
Figure 6.3 Illustration of issues with convergence on Δ
x.
Figure 6.4 Illustration of steady‐state convergence criterion.
Figure 6.5 Illustration of convergence precision.
Chapter 07
Figure 7.1 3‐D surface illustration.
Figure 7.2 Contours.
Figure 7.3 Contour map near Stillwater, OK.
Figure 7.4 (a) Net Lines and (b) contour lines.
Figure 7.5 (a) 3‐D view and (b) contour map.
Figure 7.6 Illustration of Equation (7.16).
Figure 7.7 Illustration of a function trend w.r.t. a DV line of steepest descent.
Figure 7.8 Illustrating a line in the tangent plane through the point of contact.
Figure 7.9 Illustration for Exercise 1.
Figure 7.10 Illustration for Exercise 9.
Chapter 08
Figure 8.1 Illustrating Cauchy’s sequential line search.
Figure 8.2 CSLS example.
Figure 8.3 Water following an incremental steepest descent path.
Figure 8.4 Illustrating an ISD approach to the optimum.
Figure 8.5 Zigzag approach to optimum.
Figure 8.6 First‐order filtered gradient (a conjugate gradient approach).
Figure 8.7 For Exercises 6 and 7.
Figure 8.8 For Exercises 9 and 10.
Figure 8.9 For Exercise 20.
Chapter 09
Figure 9.1 Illustrating a 2‐D placement of points to evaluate the surrogate quadratic surface.
Figure 9.2 Illustrating a 3‐D placement of points to evaluate the surrogate quadratic surface.
Figure 9.3 SQ diversion when outside of the inflection point.
Figure 9.4 Makes Newton’s oscillate.
Figure 9.5 An NR path on Function 32.
Figure 9.6 (a) A function and (b) its derivative.
Figure 9.7 Combinations of derivative shapes near the root: (a)
A–A
, (b)
B–B
, (c)
B–A
, and (d)
A–B
.
Figure 9.8 An extreme
A
shape.
Figure 9.9 An extreme
B
shape.
Figure 9.10 NR or SQ encountering a constraint.
Figure 9.11 Illustrating too large and too small increments for numerical derivative evaluation.
Figure 9.12 Illustrating the central difference numerical approximation to the local slope: (a) near the optimum and (b) away from the optimum.
Chapter 10
Figure 10.1 Illustrating zigzag behavior of CSLS.
Chapter 11
Figure 11.1 Illustration of CHD in 2‐D.
Figure 11.2 CHD on a 2‐D Function.
Figure 11.3 Pattern move in HJ.
Figure 11.4 Illustration of HJ possible exploration points in 2‐D.
Figure 11.5 Illustration of a HJ search in 2‐D.
Figure 11.6 Illustration of a HJ pattern move in 2‐D.
Figure 11.7 Illustration of a pattern move change if the pattern point is not better.
Figure 11.8 Illustration of exploration fails in HJ.
Figure 11.9 Illustration of an alternate pattern exploration layout in HJ.
Figure 11.10 HJ path on Function 13.
Figure 11.11 A simplex in a 2‐DV case.
Figure 11.12 An NM or SHH simplex move.
Figure 11.13 The NM‐SHH simplex moving toward the optimum.
Figure 11.14 Options for placement of the smaller simplex: (a) on center, (b) on the best corner, and (c) on COG of the other points.
Figure 11.15 LF explanation: (1) Initialization.
Figure 11.16 LF explanation: (2) Choosing leap‐to area.
Figure 11.17 LF explanation: (3) The leap‐over.
Figure 11.18 LF explanation: (4) Test for convergence.
Figure 11.19 LF explanation: (5) Next leap‐over.
Figure 11.20 LF explanation: (6) Test for convergence.
Figure 11.21 LF explanation: (7) Players are converging.
Figure 11.22 3‐D view of OF response to DVs in the rank application of Function 84.
Figure 11.23 LF converged results from 100 trials on Function 84.
Figure 11.24 Path of a particle in 2‐D space.
Figure 11.25 Illustration of influences on an individual particle.
Figure 11.26 Illustration of an individual particle trend toward the minimum.
Figure 11.27 Radial basis function scaling of draw.
Figure 11.28 Illustration of a steady‐state convergence criterion on the OF value of the worst particle.
Figure 11.29 Particle positions at convergence.
Figure 11.30 Surface of Function 11.
Figure 11.31 Illustration for Exercises 1 and 2.
Figure 11.32 Illustration for Exercises 3 and 4.
Figure 11.33 Illustration for Exercise 6.
Figure 11.34 Illustration for Exercise 8.
Figure 11.35 Illustration for Exercise 10.
Chapter 12
Figure 12.1 Illustration of LP concepts.
Chapter 13
Figure 13.1 (a) Time as the stage; (b) distance as the stage.
Figure 13.2 Process heater sketch.
Figure 13.3 Possible trend of temperature w.r.t. time returning to the set point.
Figure 13.4 State and stage grid for DP.
Figure 13.5 Illustration of transitions in the final stage.
Figure 13.6 Illustration of transitions in the next to last stage.
Figure 13.7 Illustration of the second to last stage transition.
Chapter 14
Figure 14.1 Illustration of selection of the fittest.
Figure 14.2 The fittest survive.
Figure 14.3 Showing (a) rank only dominated by individuals in the lower rank, (b) rank is based on the number of individuals with better fitness.
Figure 14.4 Illustration of process response and influences over time.
Figure 14.5 Illustration of membership functions for
x
1
in the categories of low, medium, or high.
Chapter 16
Figure 16.1 A strictly positive monotonic function.
Figure 16.2 Illustration of a caution on using what seems to be a strictly positive monotonic function over a limited range: (a) the original OF, (b) the OF squared, (c) and a reveal of the limit of arguments to make squaring a variable a strictly increasing transformation.
Figure 16.3 Illustration of some strictly negative monotonic functions: (a) reciprocal, (b) negative exponential, (c) negative of the log or log of the reciprocal, and (d) negative.
Figure 16.4 Common strictly increasing functions: (a) squared, (b) square root, (c) log, and (d) scaled and translated.
Chapter 19
Figure 19.1 Illustration of a scaled variable.
Figure 19.2 Scaling on a –1 to +1 basis.
Figure 19.3 Scaling on a –0.8 to +0.8 basis.
Figure 19.4 Scaling on a 0.2–0.8 basis.
Chapter 20
Figure 20.1 Reaction single DV example.
Figure 20.2 Reaction single DV example—impact of coefficient uncertainty.
Figure 20.3 Optimization of nominal and 90% worst case.
Figure 20.4 Comparison of independent and autocorrelated perturbations.
Chapter 21
Figure 21.1 Illustration of how to assign equal concern values.
Figure 21.2 Initial concept for multi‐objective treatment of two desirability metrics.
Figure 21.3 Proper structure of axes variables.
Figure 21.4 Multi‐objective Pareto chart.
Figure 21.5 (a) Sleep benefit and (b) late penalty w.r.t. wake‐up time.
Chapter 22
Figure 22.1 Sketch of the United States in an
x–y
frame.
Figure 22.2 Illustration of a fixed penalty; (a) large enough, (b) not large enough.
Figure 22.3 Illustration of a quadratic penalty added to the OF.
Figure 22.4 illustration of a quadratic soft penalty shifted by
ɛ
.
Figure 22.5 Optimization results of 100 randomly initialized trials on Equation (22.25).
Figure 22.6 Results when optimizing Equation (22.28) a slack variable transformation.
Figure 22.7 RLM solution to Equation (22.29).
Figure 22.8 Results of 100 optimizer trials from randomized initializations for Equation (22.30).
Figure 22.9 Hard constraints can block an optimizer.
Chapter 23
Figure 23.1 Multiple optima (a) discontinuous (b) continuum values.
Figure 23.2 A contour of multiple optima with 2 DVs.
Figure 23.3 A univariate function with three minima and region of attraction labeled.
Figure 23.4 Histogram of optima with randomized initializations in the OF of Figure 23.3.
Figure 23.5 Detail of histogram.
Figure 23.6 The pdf(OF*) solutions associated with Figure 23.3.
Figure 23.7 Diverse pdf(OF*) functions with the best 10% area shaded.
Figure 23.8 Illustration of a CDF(OF*).
Figure 23.9 Detail of the initial portion of Figure 23.8.
Figure 23.10 Illustration for Exercise 4.
Chapter 24
Figure 24.1 (a) Contour plot of the deterministic background. (b) One realization of the stochastic contours. (c) The surface in 3‐D.
Figure 24.2 Algae farm OF surface. One realization.
Figure 24.3 Reservoir. One realization.
Figure 24.4 Conventional optimization results on the GMC problem: (a) Levenberg–Marquardt, (b) particle swarm, and (c) leapfrogging.
Figure 24.5 Method for stochastic optimization.
Chapter 25
Figure 25.1 The function (solid line) and with perturbed coefficient values (dashed line).
Figure 25.2 Shift in the derivative due to uncertainty in model coefficient values.
Figure 25.3 CDF of DV* values in Equation (25.18).
Figure 25.4 CDF of OF* values in Equation (25.18).
Chapter 26
Figure 26.1 The profitability index distribution of two designs.
Figure 26.2 Illustration of the concept of modeling.
Figure 26.3 (a) Continuous or analytic and (b) experimental or discrete.
Chapter 27
Figure 27.1 Illustration of point values that are feasible.
Figure 27.2 Illustration of rounding the DV values to a feasible discretization.
Figure 27.3 An OF response to discretized DVs.
Figure 27.4 A motorcycle headlight configuration.
Figure 27.5 An exhaust fan configuration for a building.
Figure 27.6 The OF response to Function 56.
Figure 27.7 Representation of a branch‐and‐bound strategy.
Chapter 28
Figure 28.1 Illustration of the TSP.
Figure 28.2 A best solution to the Realtor Tour TSP example.
Chapter 29
Figure 29.1 Noise perturbing an experimental measurement.
Figure 29.2 Uncertainty on the experimental inputs—concept 1.
Figure 29.3 Uncertainty on the experimental inputs—concept 2.
Figure 29.4 Pdf of
x
and
y
overlaid on the experimentally obtained data point.
Figure 29.5 Likelihood contours surrounding the experimentally obtained data point.
Figure 29.6 The point on the curve with maximum likelihood of generating the experimental data.
Figure 29.7 Maximum likelihood with scaled variables.
Figure 29.8 The point of maximum likelihood is tangent to the highest likelihood contour: (a) the curve crosses one contour to a better contour, and (b) the curve does not touch the better contour.
Figure 29.9 Points of maximum likelihood are normal to the curve when variables are scaled by their standard deviation.
Figure 29.10 Model coefficient values to maximize the product of each likelihood in scaled variables.
Figure 29.11 Akaho’s method to approximate likelihood.
Figure 29.12 If variability is large, Akaho’s approximation loses validity.
Figure 29.13 Alternate models with equivalent validity to the data.
Figure 29.14 How SSD or rms might relax to a minimum value with progressive iterations.
Figure 29.15 How SSD or rms of a random data sample relaxes to a noisy steady state with iteration.
Figure 29.16 A not‐at‐steady‐state trend.
Figure 29.17 A steady‐state trend.
Figure 29.18 The distributions of the
r
‐statistic for three events.
Figure 29.19 Observation of rms from a random data sampling as optimizer iterations progress.
Figure 29.20 Overfitting.
Figure 29.21 A wrong model may appear to provide a reasonable fit to data.
Figure 29.22 Use of bootstrapping to reveal model uncertainty due to data variation.
Figure 29.23 Instrument calibration of salt concentration w.r.t. conductivity.
Figure 29.24 Instrument calibration of index of refraction w.r.t. mole fraction methanol in water.
Figure 29.25 Illustration for Exercise 3.
Figure 29.26 (a) Data, (b) data with uncertainty indicated by likelihood contours.
Chapter 31
Figure 31.1 3‐D view of a surface with cliffs (level discontinuities).
Figure 31.2 Contour map of a surface with level discontinuities (cliffs).
Figure 31.3 3‐D view of a surface with slope discontinuities (sharp valleys).
Figure 31.4 Contour map of a surface with slope discontinuities (sharp valleys).
Figure 31.5 A surface with a valley with steep side walls and a gentle bottom slope.
Figure 31.6 A closeup 3‐D view of a surface with striations due to numerical discretization.
Figure 31.7 A contour map of the surface section of Figure 31.6.
Figure 31.8 Results of an optimizer guided by striations, even though not visible in the large overview.
Figure 31.9 A 3‐D view of a surface with level spots.
Figure 31.10 A contour map of a surface with level spots.
Figure 31.11 3‐D view of the search for a mountain path, revealing a hard to find minimum.
Figure 31.12 2‐D contour map of the function revealing converged solutions.
Figure 31.13 Illustration of the impact of an infeasible operation encountered within the OF calculation.
Figure 31.14 Consequences of an under‐specified application.
Figure 31.15 3‐D illustration of a stochastic response.
Figure 31.16 Optimization results on the function of Figure 31.15.
Figure 31.17 The popular peaks function for testing optimizers.
Figure 31.18 Optimization on the peaks function with the LM method.
Figure 31.19 Optimization on the peaks function with leapfrogging.
Chapter 32
Figure 32.1 Illustration of an RC dc circuit.
Figure 32.2 The trend of Equation (32.10) leads to an extreme DV value.
Figure 32.3 The impact of filter coefficient on time lag of the filtered response.
Figure 32.4 Illustration for Exercise 11.
Chapter 33
Figure 33.1 Pareto comparison of two contrasting performance criteria on diverse optimizers.
Figure 33.2 Illustration for Exercise 1.
Chapter 35
Figure 35.1 Cumulative distribution function.
Figure 35.2 Global attractor area.
Figure 35.3 Comparison of data to Equation (35.22).
Figure 35.4 Comparison of data and Equation (35.26).
Figure 35.5 Optimization results from Equation (35.42).
Figure 35.6 Illustration of the pdf of leap‐to position for the first leap.
Figure 35.7 Illustration of the pdf of leap‐to position for the second leap from two locations.
Figure 35.8 Illustration of the pdf of leap‐to position for the second leap from all leap‐from locations.
Figure 35.9 Numerical results of using Equation (35.48) to determine the cumulative probability of converging after
N
leap‐overs.
Figure 35.10 Probability distributions of convergence after
N
leap‐overs. Note the semi‐log scale.
Figure 35.11 Pdf of leap‐to position after (a) one leap‐over, (b) after two, (c) after three, and (d) after four.
Chapter 36
Figure 36.1 Process illustration. Determine the optimum pipe diameter.
Figure 36.2 Impact of diameter on (a) pipe cost, (b) in‐pipe inventory, (c) pump cost, and (d) pump energy expenses.
Chapter 38
Figure 38.1 Lifetime joy as a response to retirement year and investment portion.
Figure 38.2 Optimizer results using LM.
Figure 38.3 Close‐up view of the surface revealing striations.
Figure 38.4 One realization of the surface when considering uncertainty in the givens.
Chapter 39
Figure 39.1 The concept.
Figure 39.2 An example of scheduling thrust with elevation way points.
Chapter 40
Figure 40.1 One realization of the reservoir OF.
Figure 40.2 Contour plot of one realization of the reservoir.
Chapter 43
Figure 43.1 Illustration of a vapor–liquid separator, a horizontal right circular tank.
Figure 43.2 Geometry of a segment of a circle.
Figure 43.3 3‐D view of OF with continuum variables, revealing the sharp valleys.
Figure 43.4 3‐D view of the OF with discretized
D
and
L/D
values.
Figure 43.5 The impact of the sharp valleys on a gradient‐based optimizer.
Figure 43.6 The impact of discretization on a single TS optimizer.
Chapter 44
Figure 44.1 One aspect of the optimization if
n
could be a continuum.
Figure 44.2 The OF response to
n
1
.
Figure 44.3 Response to
n
2
.
Figure 44.4 The stochastic response w.r.t.
n
1
and
n
2
.
Chapter 45
Figure 45.1 Illustration of a case of redundant measurements.
Figure 45.2 Combined flows.
Figure 45.3 Blending flows.
Appendix A
Figure A.1 Illustration of local linear approximating models.
Figure A.2 (a) Illustrating a forward finite difference and (b) a central difference.
Figure A.3 Illustration of the meaning of a partial derivative.
Figure A.4 Illustrating second derivative as the difference between sequential derivatives.
Appendix B
Figure B.1 Illustrations of the function w.r.t. the dependent variable: (a) linear and (b) nonlinear.
Figure B.2 A relation with multiple roots.
Figure B.3 Illustration of interval halving stage 1—the marching method.
Figure B.4 Illustration of interval halving stage 2—bisection method.
Figure B.5 Illustration of the secant version of Newton’s method of root finding.
Figure B.6 Illustrating a misdirection that a Newton type of algorithm can produce.
Figure B.7 Illustration of a pole in a function that could misdirect interval halving.
Figure B.8 The marching method may miss a root.
Appendix D
Figure D.1 Illustration of noisy measurements (markers) and filtered data (solid line).
Figure D.2 Data showing autocorrelation.
Figure D.3 Data showing no autocorrelation when the interval is five samplings.
Figure D.4 Example application of SSID and TSID.
Figure D.5
R
‐Statistic distribution at steady state.
Figure D.6 High chance of not being at steady state.
Figure D.7 Critical value for steady‐state identification.
Appendix E
Figure E.1 Peaks surface.
Figure E.2 Shortest‐time path surface.
Figure E.3 Hose winder device.
Figure E.4 Hose winder surface.
Figure E.5 Boot print contour.
Figure E.6 Boot print with pinhole surface.
Figure E.7 Stochastic boot print surface.
Figure E.8 Stochastic boot print contours: (a) one realization and (b) another realization.
Figure E.9 Reservoir surface.
Figure E.10 Chong Vu’s normal regression.
Figure E.11 Windblown surface.
Figure E.12 An integer problem surface.
Figure E.13 Reliability surface.
Figure E.14 Frog surface.
Figure E.15 Hot and cold mixing.
Figure E.16 Hot and cold mixing: (a) deterministic contour, (b) one contour realization with uncertainty, and (c) one surface realization with uncertainty.
Figure E.17 Curved sharp valleys surface.
Figure E.18 Parallel pumps surface.
Figure E.19 Underspecified surface.
Figure E.20 Parameter correlation surface.
Figure E.21 Robot soccer field.
Figure E.22 Robot soccer stochastic surface.
Figure E.23 ARMA (2, 1) regression surface.
Figure E.24 Algae pond contour.
Figure E.25 Algae pond: (a) stochastic contour and (b) stochastic surface.
Figure E.26 Classroom lecture pattern.
Figure E.27 Peaks contour.
Figure E.28 Mountain path of contour w.r.t. path coefficients
c
(horizontal) and
d
(vertical).
Figure E.29 Chemical reaction with phase‐equilibrium surface.
Figure E.30 Cork board sketch.
Figure E.31 Cork board surface.
Figure E.32 Three springs surface.
Figure E.33 Retirement (deterministic surface).
Figure E.34 Detail of retirement surface.
Figure E.35 Retirement stochastic surface.
Figure E.36 Solving an ODE.
Figure E.37 Space slingshot illustration.
Figure E.38 Space slingshot surface.
Figure E.39 (a) A best path and (b) a nearly as good path.
Figure E.40 A Goddard problem surface.
Figure E.41 Rank model surface.
Figure E.42 Liquid–vapor separator surfaces: (a) continuum size variables and (b) discretized size.
Figure E.43 Liquid–vapor separator issues for optimizers: (a) effect of ridges and (b) effect of flat spots.
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Engineering Optimization Applications, Methods and Analysis
Rhinehart
March 2018
Robust Adaptive Control for Fractional-Order Systems with Disturbance and Saturation
Chen
November 2017
Robot Manipulator Redundancy Resolution
Zhang
October 2017
Combined Cooling, Heating, and Power Systems: Modeling, Optimization, and Operation
Shi
August 2017
Applications of Mathematical Heat Transfer and Fluid Flow Models in Engineering and Medicine
Dorfman
February 2017
Bioprocessing Piping and Equipment Design: A Companion Guide for the ASME BPE Standard
Huitt
December 2016
Nonlinear Regression Modeling for Engineering Applications
Rhinehart
September 2016
Fundamentals of Mechanical Vibrations
Cai
May 2016
Introduction to Dynamics and Control of Mechanical Engineering Systems
To
March 2016
Applications, Methods, and Analysis
R. Russell Rhinehart
This Work is a co‐publication between ASME Press and John Wiley & Sons Ltd.
This edition first published 2018© 2018 R. Russell RhinehartThis Work is a co-publication between ASME Press and John Wiley & Sons Ltd
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Library of Congress Cataloging‐in‐Publication Data
Names: Rhinehart, R. Russell, 1946– author.Title: Engineering optimization : applications, methods and analysis / by R. Russell Rhinehart.Description: First edition. | Hoboken, NJ : John Wiley & Sons, 2018. | Includes index. |Identifiers: LCCN 2017052555 (print) | LCCN 2017058922 (ebook) | ISBN 9781118936313 (pdf) | ISBN 9781118936320 (epub) | ISBN 9781118936337 (cloth)Subjects: LCSH: Engineering–Mathematical models. | Mathematical optimization.Classification: LCC TA342 (ebook) | LCC TA342 .R494 2018 (print) | DDC 620.001/5196–dc23LC record available at https://lccn.loc.gov/2017052555
Cover design: WileyCover image: © John Wiley & Sons
Optimization means seeking the best outcome or solution. It is an essential component of all human activities. Whether personal or professional, we seek best designs, best choices, best operation, more bang for the buck, and continuous improvement.
Here are some professional examples: Minimize work events that lead to injury while remaining economically competitive. Structure workflow to maximize return on investment. Design an antenna that maximizes signal clarity for a given power. Define a rocket thrust sequence to maximize height. Determine the number of parallel devices to minimize initial cost plus future risk.
Here are some personal examples: Seek the best vacation experience for the lowest cost. Minimize grocery bill, but meet desires for nourishment and joy of eating. Set the family structure for raising children that leads to well‐adjusted, happy, productive outcomes, but keep within the limits of personal resources. Create a workout regime that leads to fastest and most attractive muscle development, with no injury, and in balance with other desires in quality of life.
Optimization is not just an intellectual exercise; although often, solving the challenge is as rewarding as completing a Sudoku puzzle. We implement the optimized decision. Accordingly, within any application it is essential to completely and appropriately assess the metrics that quantify “best.” If the description of what you want to achieve is not quite right, then the answer will also be wrong, which the implementation will reveal in retrospect. You want to get it right prior to implementation. So, part of this book is about development of the optimization objective.
After the objective is stated, we desire an efficient search logic to find the best solution, with precision and with minimal computational and experimental effort. So, other parts of this book are about the optimizer—the search logic, or algorithm.
Both aspects are essential, and I find that most books on optimization focus on the intellectually stimulating mathematics of the algorithms. So, I offer this book to provide a balance of essential topics to the application to guide user choices in structuring the objective, defining constraints, choosing convergence, choosing initialization, etc. Some will be disappointed that this book is not a compendium of every optimization algorithm conceived by mankind. However, others will value the application perspective.
Also, I find that most people using optimization as a tool did not have a course on it while in school. So, I have written this book in a style that I hope facilitates self‐study by those who need to understand optimization applications while keeping it fit for use as a graduate‐school course textbook.
Here are a few essential aspects of optimization:
Point 1: Although optimization offers the joys of solving an intellectual puzzle, it is not just a stimulating mathematical game. Optimization applications are complicated, and the major challenges are the clear and complete statement of:
The objective function (OF—the outcome you wish to minimize or maximize)
Constraints (what cannot or should not be violated, or exceeded)
The decision variables (DV—what you are free to change to seek a minimum)
The model (how DVs relate to OF and constraints)
The convergence criterion (the indicator of whether the algorithm has found a close enough proximity to the minimum or maximum and can stop or needs to continue)
The DV initialization values
The number of starts from randomized locations to be confident that the global optimum has been found
The appropriate optimization algorithm (for the function aberrations, for utility, for precision, for efficiency)
Computer implementation in code Oh yes,
The mathematics of the optimization algorithm (understanding this is also important)
This book seeks to address all 10 aspects, not just the 10th.
Point 2: Do not study. Learning is most effective if you integrate the techniques into your daily life. You will forget the material that you memorized in order to pass a test. Since this book provides skills that are essential for both personal and career life, I want you to take the techniques with you. I want this book to be useful in your future. Although memorization and high‐level mathematical analysis are both elements of the book, understanding the examples and doing of the exercises is more important. To maximize the impact of this material, you need to integrate it into your daily life. You need to practice it.
Oh, I see I omitted a comma in the first sentence of the paragraph above. It should have been “Do, not study.” Learn by doing. After you read a section and think you understand it, see if you can implement it. Of course, the comma “error” above was intentional to wake up curiosity about the message.
Point 3: Optimization is universal to all engineering, business, science, computer science, and technology disciplines. Although primarily written for engineering applications, this introductory book is designed to be useful for all those seeking to apply optimization in all fields.
Point 4: The implementation of optimization requires computer programming, which for many is an aggravation. To help the reader, I currently have, and plan to support, a website that offers to any visitor optimization software and examples. Visit www.r3eda.com. The “r3” in the address is my initials, and the appended “eda” means “enabling data analysis.” Seeking to maximize ease of use and accessibility, the programs are written as VBA macros for MS Excel. VBA is not the fastest‐computing environment, nor does it have the best scientific data processing functions. However, it has been adequately functional for all of my applications, and if you need something better, the code can be translated. This book provides a VBA primer (Appendix F) for those needing the help in accessing and modifying the code. The programs on the r3eda site solve many of the examples in this book.
Readers should be pleased with their ability to:
Understand and use the fundamental mathematical techniques associated with optimization
Define objective functions, decision variables, models, and constraints for a variety of optimization applications
Develop, modify, and program simplified versions of the more common optimization algorithms
Understand and choose appropriate methods for:
– Constrained optimization
– Global optimization
– Convergence criteria
– Surface aberrations
– Stochastic applications
Understand diverse issues related to optimizer desirability
Explore, contrast, and evaluate the performance of optimization algorithms and user choices of convergence criteria, numerical derivative estimation, threshold, constraint handling method, parameter values, etc. with respect to precision, user convenience, and other measures of optimizer desirability
Apply optimization algorithms to case studies relevant to the reader’s career
Continue learning optimization methods from texts, reports, Internet postings, and refereed journal articles
Optimization is the name for the procedure for finding the best choices. “Procedure,” “best,” and “choices” are separate aspects, and the user must understand each to be able to appropriately define the application. And each aspect has a large range of options.
This relates to the method used to find the optimum:
In process or device design, for example, the choices could be the equipment specifications (type, materials, size), and the evaluation of best in the design could be to minimize capital cost with a constraint on reliability. With mixed continuous, discrete, and class variables as the choices, a direct search algorithm might be the best optimizer.
Alternately, in scheduling a rocket thrust to reach a desired height, the stage choices might be height, best might be evaluated as minimizing either time or fuel use, and the appropriate algorithm might be dynamic programming.
Another example is characterized as the traveling salesman problem in which the objective is to determine a sequence of locations to visit to minimize travel distance. Here the choice is the sequence, and the best sequence might be impacted by a priority of visits, expenses, wasted time, etc. The procedure might use the random keys method to convert a sorted list of rational numbers into the sequence.
As a final contrasting example, in model‐predictive control, the objective might be to minimize time to move a response to a set point while penalizing excessive manipulated variable moves while avoiding constraints; and the choices might be the future sequence of manipulations. If the penalties are quadratic, the appropriate algorithm might be a gradient‐based procedure.
Within optimization terminology, the definition of best for a specific application (and the method for calculating a value to quantify best) is variously termed the cost function or the objective function (OF). It is the function that returns a value representing an assessment of goodness. Best usually means minimize undesirable aspects and/or maximize desirable aspects, and the OF can represent a wide range of metrics related to economics, safety, time, resource conservation, quality, deviation, probability, etc. But best might mean to minimize a worst‐case feature (min the max, or min–max), such as finding a path through mountains that minimizes the steepest ascent or finding a process design that minimizes the worst‐case outcome (risk).
Defining the appropriate OF is situation specific, and often it is the key challenge in an optimization application. The user needs to clearly understand the complex situation and realize that a first statement of the OF usually embodies a superficial understanding. Subsequent analysis of the results will lead to an evolution of the OF. For example, a challenge might be to choose the best pipe diameter in a process design. A smaller diameter means a less expensive pipe and lower in‐pipe inventory cost, but it means a larger pump. An initial OF choice might be to minimize capital. However, reconsideration from a business investment view might reveal that operating costs associated with pumping power and maintenance are also important issues, and perhaps net present value (NPV) is a right way to combine initial capital with future expenses. Then, reconsideration might bring understanding of the sensitivity of the optimum solution to uncertainty in the “givens,” which will lead to a refinement of the OF to represent the 95% worst case of the NPV in a Monte Carlo analysis, making it a stochastic function. Risk might then be perceived as an additional issue, and the OF might be split into a multi‐objective version (risk and NPV) that provides a non‐dominated set of solutions for a user to select a best for the particular situation. Finally, the user might realize that pipe comes in discrete diameter values and that the pipe diameter is not a continuous‐valued number. This application might have evolved from an initial simple deterministic (textbook example) case to a complicated application, classified as mixed integer, stochastic, and multi‐objective.
This book will address how to develop the OF and will show examples from a wide range of applications.
The choices a user has (you may call these inputs, decisions, degrees of freedom, or independent variables) to change things toward the best outcome are termed decision variables (DVs).
