Currently learning stochastic optimization (SO) theory, I will note important content here.
Multi-stage vs Multi-period
- Stage: is defined according to decisions made
- Period: is defined according to the occurence of random events
For example, consider a facility location problem considering random daily demands in the future. Fixing the location of facilities is one-stage decision, while the random demands occur every day, so it is about multi-period.
Define Stages
As i understood, the basic form of a two-stage problem:
optimize
where is the first-stage decision, while is a random event. The objective is to find the optimal FIRST-STAGE decision resulting the best expected profit/cost.
Time Line
1st stage decision (here and now) -> some uncertainty disclosed -> 2nd stage decision (wait and see)-> some uncertainty disclosed…