Elevator Design
When I first interviewed tojoin MSFT,I was asked to describe how I would design an elevator scheduling system. Prior to joining MSFT I worked on a couple of traffic flow sensor systems for roadways, so it was easy to make up some convincing suggestions, but I’ve often wondered about how it’s really done with elevators.Now I am learning more than I ever wanted to know about this problem– right at this moment I’m sitting in a presentation being given by a researcher who works for the industry and he is going into serious detail about some projects they did to track pedestrian traffic, optimize elevator schedules, and so on. Who ever knew there were so many things to think about when designing a building? Not intending to give it all away, but some simple notes:
- Don’t optimize for minimized wait time necessarily; the people who pay for the building care more about efficiency.
- Efficiency involves size of elevator shaft, energy consumption, etc.
- Most algorithms schedule based on past history of temporal events (floor 1 called from floor 5), etc. Lots of IP in this area
- Tracking pedestrian traffic can find some significant patterns, and provide better results than just button-based predictions. Suggests that this is cost-effective