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Show HN: Elevators

john.fun

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Re: Show HN: Elevators

#151

Post by namibj »

hypersoar wrote: post #81
dperfect wrote: post #64

Earlier quoted context omitted.

That sounds like two separate things then. Could you not have people select a destination without locking in an elevator? (I've never encountered destination dispatch myself, so I'm not really sure how it works in practice)

The way I've seen it work is that there's a touch screen in the elevator lobby. You tap a floor, and then screen will say "Car C" (along with an audible message). The problem is that then the system can't reassign you to a different car after that. You'll typically have a bunch of different people going to a bunch of different floors, and there would be no reliable way to communicate to each individual their new assi…

You could give each one a diceware-eff-wordlist-like "ID" when they input where they want to go, perhaps have a "group" and "single" button/column per destination in the menu as well to inform the elevator if it's a group traveling together, and importantly have a fast-food-pickup-counter style dispatch screen up top visible from the waiting "hall", that assigns you a cab with an appropriate notice/heads-up period so you can make your way over to the assigned cab.

Re: Show HN: Elevators

#152

Post by dawnerd »

omoikane wrote: post #68

> Destination Dispatch [...] are in general worse I wonder if this is an artifact of how the author used random destinations. I worked in a building that used Destination Dispatch, and the common travel pattern seemed to be: - Everyone who is not on the ground floor generally want to go to the ground floor. - People who are on the ground floor generally travel in large groups to the same destination. This happens bec…

Cruise ships that use destination dispatch have been much nicer too. Ships that use the older algorithms are a pain to wait during peak times. Guess plus side you’ll use the stairs more.

Re: Show HN: Elevators

#153

Post by hermanschaaf »

jamies wrote: post #39
hermanschaaf wrote: post #24

Hah, I thought a lot about this problem while developing Sky Lobby, a mobile game (iOS / Android) about controlling and automating elevators. In the game, some of the elevators are automated, and I wanted to choose an algorithm that best aligned with what players would expect an elevator to do. I ended up going with something close to LOOK, which (as the article states) is mostly what people expect. Except in case of…

Thanks for sharing this. I was just commenting about the challenge of making a fun elevator sim game. This looks great -- can't wait to play with it this weekend!

Thanks! Would love to hear your thoughts if you get a chance to play it. I'm currently working on adding a few more towers and challenges. After that maybe I'll deep-dive into the "best" automated scheduling algorithm for all this :)

Re: Show HN: Elevators

#154

Post by genericone »

CobrastanJorji wrote: post #108
brandonpelfrey wrote: post #6

For folks that have never seen elevator scheduling the game: https://play.elevatorsaga.com/ Enjoy this rabbit hole :D

This is great, but to me, the definitive elevator scheduling game was SimTower.

Sid Meier's Elevator Manager was such a great game... so much nostalgia.

Re: Show HN: Elevators

#155

Post by hypercube33 »

hypersoar wrote: post #81
dperfect wrote: post #64

Earlier quoted context omitted.

That sounds like two separate things then. Could you not have people select a destination without locking in an elevator? (I've never encountered destination dispatch myself, so I'm not really sure how it works in practice)

The way I've seen it work is that there's a touch screen in the elevator lobby. You tap a floor, and then screen will say "Car C" (along with an audible message). The problem is that then the system can't reassign you to a different car after that. You'll typically have a bunch of different people going to a bunch of different floors, and there would be no reliable way to communicate to each individual their new assi…

After visiting a hospital with like 5 floors and 2 elevators people were having a hell of a time with just 'going up ' or down arrows

Re: Show HN: Elevators

#156

Post by [deleted] »

peterldowns wrote: post #78

Back in highschool, simulating different elevator algorithms was one of the projects I implemented during my CS class. It wasn't for the class — AP CS did not require anything like actual programming — but it was a fun project. A cool connection is that a spinning-disk hard drive (HDD) is actually kind of like one really long elevator, just wrapped around a spindle instead of perfectly vertical. The SCAN algorithm is…

[deleted]

Re: Show HN: Elevators

#157

Post by crabbone »

The question about designing elevators used to be the mainstay of programming job interviews. I had an annoying interview where I was asked, for the umpteens time to design an elevator. I already made up my mind at the time, knowing I'm not going to work for the company, but decided to have a... unexpected approach.

So, for instance, I didn't measure the elevator's efficiency in the wait time. I included (weighted) travel time. I assumed LOOK algorithm was used. And then when I tried to calculate various outcomes for different trips I suddenly realized that elevator's efficiency and fairness seem to go different ways.

Without trying to reproduce my evaluation system, here's my finding in fewer details: if you have two passengers, one going from the ground floor to the top floor and other joining for the shorter ride down in the middle, then the elevator that makes a "detour" is more efficient, but it hardly seems fair that the passenger traveling ground floor to the top should go even a single floor in the opposite direction.

Somehow, until that point, I lived with an illusion that the most efficient solution to a problem must be the most fair to every participant. Discovering this counterexample sent me on the "tour of discovery" of ethics and different philosophers who contributed to it... and while in the end it made me none the wiser, I'm happy to have discovered this field.

Re: Show HN: Elevators

#158

Post by salberts »

Our elevator (4 cars) displays above each car the planned stops and can change mid-wait the carfloor allocation and issue sound indication. I’d expect it to be allow optimal allocation.

Re: Show HN: Elevators

#159

Post by vel0city »

olex wrote: post #17

The biggest problem I always have with elevators is not the algorithm, it's the people seemingly being unable to grasp the concept of pressing either the up or the down request button, depending on where they want to go. Almost always I find someone will press both, because "then the elevator comes faster". Completely ignoring the fact that they end up going the wrong way first half the time, and adding an unnecessar…

When you're at a lower floor and you're trying to go down, but its a time period where traffic is trying to leave you can end up in a situation where nearly every elevator going down is already full. So you call for down, cab arrives but is already full, it goes, you call again, another comes, its already full, rinse/repeat. Sometimes there's not much up traffic during that time, so it can be a legit strategy to just go ahead and call on the up and ride it all the way instead of waiting and hoping for space coming down.

Although I guess that's not quite what you're talking about.

Re: Show HN: Elevators

#160

Post by userbinator »

It's worth noting that for roughly half of the last century, elevators were entirely controlled by relays, with no computers at all; these algorithms would be implemented in hardwired logic. Look at Otis' old patents for some interesting details, including schematics.
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