ISBN: 3540298789
TITLE: Introduction
AUTHOR: Vo, Woodruff
TOC:

1. Introduction 1
1.1 Supply Chains and Production Planning 1
1.2 Optimization 2
1.3 Components of Supply Chain Management 4
1.4 Scope of this Book 5
2. Optimization Modeling 7
2.1 Abstraction 7
2.2 Symbols 9
2.2.1 Variables, Data, Subscripts, and Math 9
2.2.2 Sets 11
2.2.3 Objective Functions and Constraints 11
2.3 Finding Solutions 14
2.3.1 Data 15
2.3.2 A Few Words About Uncertainty 15
2.3.3 Solvers and Model Structure 16
2.4 Implementing the Models in this Book 17
3. Starting with an mrp Model 19
3.1 An Example 19
3.2 mrp Mechanics 20
3.3 mrp Data 22
3.4 mrp Optimization Formulation 24
3.5 Discussion of mrp 26
3.5.1 Troubles 27
3.5.2 Virtues 29
4. Extending to an MRP II Model 31
4.1 MRP II Mechanics 31
4.2 MRP II Data and Constraints 34
4.3 Discussion of MRP II 36
4.4 Changeover Modeling Considerations 38
4.4.1 A Straightforward Modification 38
4.4.2 Production that Spans Time Buckets 39
4.4.3 Parallel Machines 40
4.4.4 Sequence Dependent Changeovers 41
4.4.5 A Few Remarks About Changeovers 42
5. A Better Model 45
5.1 A Cost Based Objective Function 45
5.1.1 Costs 45
5.1.2 Objective Function 47
5.2 Overtime and Extra Capacity 49
5.2.1 A Simple Model 49
5.2.2 Complications 50
5.3 Allowing Tardiness 51
5.3.1 A Simple Model 52
5.3.2 Complications 53
5.4 Objective Function Issues 54
5.5 The Model 55
6. Extensions to the Model 59
6.1 Substitutes, Multiple Routings and Subcontractors 59
6.2 Penalizing Changes to the Plan 62
6.3 End-of-horizon Effects and Minimum Inventories 64
6.4 Modeling Product Movement and Transport 66
6.4.1 Simple Product Movement and Shipping 67
6.4.2 Expedited Shipping 67
6.4.3 Fixed Costs and Consolidations 67
6.4.4 Transportation Discounts 69
6.4.5 Discussion of Transportation Modeling 70
6.5 Summarizing the Model 70
6.6 Aggregation and Consolidation 71
6.6.1 Consolidating Resources 73
6.6.2 Aggregating Parts 74
6.6.3 Discussion of Disaggregation 79
7. Implementation Examples 81
7.1 AMPL 84
7.1.1 mrp Model 86
7.1.2 mrp Data 87
7.1.3 Results of Running mrp 88
7.1.4 MRPII Model 89
7.1.5 Data for MRPII 90
7.1.6 SCPc Model 91
7.1.7 Data for SCPc 94
7.2 GAMS 96
7.2.1 mrp and MRPII Models 98
7.2.2 SCPc Model 101
7.3 Maximal MPL 106
7.3.1 mrp Model 107
7.3.2 MRPII 109
7.3.3 SCPc 110
7.4 OPL 114
7.4.1 mrp 115
7.4.2 MRPII 118
7.4.3 S CPc 118
7.5 Xpress-Mosel 123
7.5.1 mrp Model 125
7.5.2 mrp Data 128
7.5.3 mrp Results 129
7.5.4 MRPII Model 129
7.5.5 SCPc Model 130
8. Solutions 135
8.1 MIPs and Relaxations 135
8.2 Branch and Bound 138
8.3 Special Variable Types 141
8.3.1 Semi-continuous Variables 141
8.3.2 General Integer Variables 142
8.3.3 Special Ordered Sets 143
8.4 Heuristic Search Methods 145
8.4.1 A Brief Primer an Heuristics 146
8.4.2 Abstract Formulation and Solution Representation 147
8.4.3 Example of an Embedded Problem 149
8.4.4 Neighborhoods and Evaluation Fundions 150
8.4.5 Simulated Annealing 154
8.4.6 Tabu Search 156
8.4.7 Genetic and Evolutionary Algorithms 157
8.5 Constraint Programming 160
9. Some Stochastic Extensions 163
9.1 Lead Times and Congestion 164
9.1.1 The Issues 165
9.1.2 Load Dependent Lead Times 167
9.1.3 Solver Issues 170
9.1.4 Example 172
9.1.5 Complications and Discussion 173
9.2 Scenarios 174
9.2.1 The Issues 175
9.2.2 A Multi-stage Probabilistic Model With Recourse 178
9.2.3 Progressive Hedging 180
9.2.4 A PH based Heuristic for SCPc 184
10. Research Directions and References 187
10.1 Supply Chain Management 187
10.1.1 The Evolution of Logistics 188
10.1.2 Closed Loop Supply Chains and Reverse Logistics 191
10.1.3 The Importance of Information Technology 191
10.1.4 Supply Contracts 198
10.2 mrp, MRP II and Beyond 200
10.2.1 The Early Steps 200
10.2.2 Supply Chain Planning 201
10.3 Production Planning and Scheduling 202
10.3.1 Lot Sizing Models 202
10.3.2 Planning and Inventory Control 208
10.3.3 Machine Scheduling 211
10.3.4 Aggregation and Part Families 212
10.3.5 Load Dependent Lead Times 214
10.4 Transportation 219
10.5 Optimization 223
10.5.1 Exact Methods 225
10.5.2 Heuristic Search Methods 225
10.5.3 Progressive Hedging 229
10.5.4 Simulation 230
10.6 Modeling 231
Bibliography 233
Index 253
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