Search
Social Connections
Monday
Jun102013

Where's My Elevator?

If I ever got a job teaching introductory computer science, the first major assignment I would give would be to write an algorithm for the optimal distribution of a bank of elevators. If the current state of the art is any indication, everyone would fail.

I know it doesn't sound thrilling to most, but there's actually nothing more intriguing than standing in the lobby of a large building and watching the crazy paths some elevators take to pickup their cargo. Often, you can guess the algorithm used by just observing the traffic. There's the Stay-Where-You-Are-And-Wait algorithm. This one usually lead to a mad dash from all floors when the first request comes in. Others employ the sometimes more optimal Half-Sit-On-The-Top-Floor-The-Other-Half-Sit-On-The-Ground-Floor algorithm, which usually leads to confusion when picking up passengers in the middle ("Are you going to go get him, or shall I? Me? No, you? Wait, I'll get him. Oh, okay, you've got him.") Then there's the Whichever-One-Is-Going-In-The-Same-Direction algorithm. You can be on the 2nd floor with 10 elevators sitting on Ground, but if you push the 'down' button, you'll have to wait as an elevator from the 40th floor slowly makes its way to you. Apparently, elevators are subject to a new law of physics which makes moving a short distance, stopping, and returning, too difficult.

There is nothing...NOTHING...more frustrating than waiting for an elevator, only to have it shoot right past your floor! Unless, of course, it's finally getting an elevator to stop at your floor, only to find that it's filled to capacity and you're staring face-to-face with 20 stressed and cramped passengers who are all silently giving you signals that if you even attempt to enter the car, you should not expect to exit alive.

The building I used to work in had a frustrating flaw in its elevator control system. Say I was on the 5th floor and requested an elevator going down. It would dispatch a free car from, say, the 10th floor to come and get me. If another elevator going up happened to stop on the 5th to release a passenger, the algorithm was totally confused. My elevator would think "Well...I was called to pick up Don on the 5th floor, but I see there's already an elevator on the 5th, so he can take that one." and would bail on coming to pick me up. Of course, I didn't want to go UP with the rest of the people in the 5th floor car, so I essentially got dropped from the system. My request light would be extinguished, and I would have to try all over again.

Modern elevators have been in existence since the mid-1800s and the technology hasn't really changed all that much over the years. The system has become automated, and significantly safer, but modern advances in computer systems has done little to help optimize the flow of traffic. I witnessed one valiant effort on a recent trip to the West Coast. 

My hotel was equipped with an elevator system with NO floor buttons inside the car. You had to tell the elevator which floor you wanted when you called it. This way, it could optimize elevator usage. For instance, to get to your room from the lobby, you would press your floor number on one of a series of panels in the hallway, and the system would tell you which elevator to take when it arrived. Only the named elevator would be told to stop on your floor. Of course, this led to all kinds of interesting scenarios. If you got on the wrong elevator, you were toast. If you happened to be chatting with your colleagues as they called the elevator, and you all entered the same one, you had better hope they were staying on the same floor as you. There was nothing funnier than seeing people walk into a waiting elevator car, wait until the doors closed, and then look for a button to press, not finding any. Talk about a feeling of entrapment!

One additional feature of this system, was that you could simply 'scan' your room card in the elevator hallway, and it would know what floor to send you to without you even pushing a button. Well...in theory at least. In my case, when I scanned my room keycard, the system requested an elevator for "Floor 31" on my behalf. Unfortunately, my room was located on the 21st floor. That's progress for you.

I'm sure that being in the elevator business must have its ups and downs (Come on! You knew I was going to say something like that, didn't you?). But I think it's time we put some real effort into optimizing the algorithms in these systems. If you ever have me as your computer science teacher...you'd better be prepared!

    Don

PrintView Printer Friendly Version

EmailEmail Article to Friend

References (43)

References allow you to track sources for this article, as well as articles that were written in response to this article.
  • Response
    Response: minecraft gratuit
    The Bag Variation of indie mega-virtuoso Minecraft was purchased a stupefying 5711 times across the iOS and Mechanical man application online in 2014.
  • Response
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    Response: hcg las vegas
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    Response: lovely dogs
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    Response: telefonsex
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    Response: zillow
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    Response: porcelain tile
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    Response: chiroractic
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    Response: nyc seo
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    Response: xovilichter
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    Response: xovilichter.co.in
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    Response: this website
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    Response: lose fat
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    Response: ministry positions
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    Response: Frank Dellaglio
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    Response: Frank Dellaglio
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    ConnectWithDon - Technology - Where's My Elevator?
  • Response
    Vive a bordo di mantenere l'Evoluzione delle competenze non può essere né Arcanum, Ma il suo potere non può dimostrare il potere e l'effetto di Rapido Progresso, è difficile.Di conseguenza, il Fronte Freddo che 翁比 naturale
  • Response
    Response: parajumpers salg
    Ma quando il Fronte Freddo Quando ha preso l'Oro Spar anche Carati Strano gli occhi, non Ho potuto Fare a meno di Flash di Luce per avidita '.Qualcosa di Buono!L'Oro è anche il dio - Re Spar, che molti non Sono il ragazzo d'Oro di Pietra,paraj
  • Response
    Even some of the more well-known hair oil products like Moroccan Oil have several chemicals in them that simply are not great for your hair. You will also love the fact that Mira hair oil does not have to be used for the rest of your life. Many people find that ...
  • Response
  • Response
    Response: serrurier paris 17
    serrurier paris 17
  • Response
    Response: ipro academy bonus
  • Response

Reader Comments (2)

Buttons on the inside were all that was needed to make this system viable. Some engineer opted for algorithmic purity rather usability. Some of the optimization will be lost - but users will be happier. Version 2 here we come.

BTW: Why not let me 'opt in' with a cell phone app? I can call for my floor as I walk into the hotel or am leaving my room. The app could also show me where all the elevators are and where they are headed while I wait.

June 10, 2013 | Unregistered CommenterCraig

Excellent put up, very informative. I wonder why the opposite experts of this sector do not understand this. You must proceed your writing. I’m confident, you have a huge readers’ base already!

August 8, 2015 | Unregistered Commenterwearable technologies

PostPost a New Comment

Enter your information below to add a new comment.

My response is on my own website »
Author Email (optional):
Author URL (optional):
Post:
 
Some HTML allowed: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <code> <em> <i> <strike> <strong>
Main | A Quarter Century in Tech »