Saturday, May 7, 2011

Elevators

Old school Polish elevators are something of a curiosity.  They are prevalent in the old blocks, even if one thinks that they violate basic safety codes.  Instead of two doors, these old lifts have a single door that opens outward (it's kind of like walking into a small closet that ascends.)  When the door closes, the elevator rises without an inner door, so you can see the wall climb.  A favorite pastime is to see how fast you can write graffiti on the space between floors before it pass you by.

The new elevators are pretty typical, like you would see anywhere.  Like most things these days—from your toaster to your fridge to your car—they are controlled by microchips that run certain algorithms.  These algorithms, however, are actually pretty shitty and could use a good tune up (imagine your toaster either scorching your bread or barely warming it.  You would say, "What a crappy purchase.  I need a new one.")  Many times have I encountered two elevators side-by-side, that respond to the same button.  Ideally, you would press the button and the elevator that would take you to your destination the quickest and most efficiently would open up and take you (e.g. if you wanted to go down, an already-descending one would pick you up on the way.)  That's not how it works.  Press the button and usually nothing will happen for a space of time, before the least logical choice slowly comes to your floor.  Have an elevator that's one floor away and not carrying anyone?  You're going to have to wait for the one that's thirteen floors away go up in the opposite direction, pick someone up, and then go down to the parking garage, then come to you, all the while the other elevator patiently waits at its floor.  As I said, these elevators need tune ups.

14 comments:

Damien Moran said...

Jesus, you literally took the words right out of my fingers. What a sensible post that I'm sure rings true with many. Yet, it's not just the older blocks. I live in a block that is about 15 years old. There are 2 lifts. 1 is not appropriate for those who suffer from claustrophobia. The other is not really favourable for those who like to ascend and descend a few floors and not get hungry in the meantime. I'm no technician, but I'm sure it can't be that hard to fix. As for traffic lights and pedestrian, oh christ, don't get me started:-)

odrzut said...

In the defence of crappy elevator algorithms:

the algorithms have to assure each floor will be eventualy served, so they can't simply go to the nearest floor where somebody waits, because then if the elevator was on the first floor and people are constantly wanting to go from the first to the second floor and vice-versa, then people on the 8th floor won't ever be served.

So these algorithms are usually constructed in such a way, that when they go up, they go as far up as needed, and only then they reverse. The same aplies when they go down. This makes it look stupid for people waiting on the first floor, when the elevator goes from the 2nd to the 11-th before going back to the 1st, but it assures the people on the 11th will be served.

The alternative is much more complicated algorithms, that counts for how many seconds people on each floor already waits, and calculates how to minimize the sum of the squares of the waiting time for each floor int the building.

Squares because we have to make sure single floor waiting 30 seconds is worse than 3 floors waiting 10 seconds.

This would need much better chips, because this is NP-complete algorithmic problem ( http://en.wikipedia.org/wiki/NP-complete ) , which means it can't be solved easily and it is computationaly expansive.

There is probably room for optimization of current algorithms, but I wouldn't say they are as stupid as it sometims look.

Nom de Plume said...

We forget how much we rely on things like this lol

kartoshka said...

crazy..

Nicolas Cage said...

Nice post

Alex Devries said...

i like your blog alot, following... also you are completey right

PolishMeKnob said...

Odrzut, you are simply too smart for this blog.

Well, yes, but seriously, these algorithms need a serious optimization (I'm so serious, I used the word twice in a sentence.)

Miyamoto Karyuu said...

I was always afraid of elevators xD

The Wired said...

wow, very well put, never knew..

slash971 said...

and I'm claustrophobic... :O

CounterCulture said...

I get down on some elevator music :D

Jay Reid said...

lol, this entertained me today. Thanks. Update more :)

Buzbee said...

very much entertaining lol

tony said...

i have never even SEEN an old fashioned elevator!