Merging AI and OR to solve high-dimensional stochastic optimization problems using approximate dynamic programming

We consider the problem of optimizing over time hundreds or thousands of discrete entities that may be characterized by relatively complex attributes, in the presence of different forms of uncertainty. Such problems arise in a range of operational settings such as transportation and logistics, where the entities may be aircraft, locomotives, containers, or people. These problems can be formulated using dynamic programming but encounter the widely cited ‘curse of dimensionality.’ Even deterministic formulations of these problems can produce math programs with millions of rows, far beyond anything being solved today. This paper shows how we can combine concepts from artificial intelligence and operations research to produce practical solution methods that scale to industrial-strength problems. Throughout, we emphasize concepts, techniques, and notation from artificial intelligence and operations research to show how these fields can be brought together for complex stochastic, dynamic problems.