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Show HN: Elevators

john.fun

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Re: Show HN: Elevators

#381

Post by grishka »

woeh wrote: post #296
ehsankia wrote: post #283

Earlier quoted context omitted.

I don't understand why the fact that it's an Airbnb really matters here? Unless a large number of apartments are meant to be empty, why does it matter if the tenant is short term or long term? Is it that short term users leave and enter their apartment more often?

I am of course just speculating (and I had a lot of waiting time to think about this), but there are a lot of people with a lot of luggage constantly going in and out. It makes the elevators be full faster (perhaps there is a weight based sensor to determine if the elevator is full, and the luggage tricks the system into thinking the elevator is not full yet, because a piece of luggage is lighter than a person but so…

TIL that there are countries where the building code doesn't enforce the minimum number of elevators. In Russia it's one for buildings taller than 5 floors, two for taller than 9, and I believe three for taller than 16 (every 20-something-floor building I've ever been to had at least three). But we don't have many skyscrapers so I'm not sure how it works for those.

Re: Show HN: Elevators

#382

Post by MichaelDickens »

Neywiny wrote: post #368
theodorejb wrote: post #353

The worst situation I've encountered is after a large conference when everyone is leaving the hotel at once. An elevator quickly fills up on the way down, but then wastes time stopping at every subsequent floor with a call, even though no one else can fit inside. At each floor the elevator stops, the doors open, the waiting people see it's already packed, the doors close, and this repeats on the next 15 floors before…

It would have to be done by weight. If you had a button to not allow stopping for others, people would abuse it. If it was a camera, security issue. Presumably if somebody is moving a piano or something else heavy it'll be fine

Following rz2k's suggestion, you could have a building employee operate the elevator during busy times.

Re: Show HN: Elevators

#384

Post by fragmede »

vova_hn2 wrote: post #197
brandonpelfrey wrote: post #6

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

Very fun indeed! Can't believe, that this [0] solution to Challenge #5 actually worked, lol Challenge #6 is "Transport 40 people using 60 elevator moves or less". Unfortunately docs don't make it clear what exactly counts as a "move". [0] https://gist.github.com/vovanz/66e4396934ac656a8f8c32fcee43d...

bogosort!

Re: Show HN: Elevators

#385

Post by MostlyStable »

Given that there is already a simulation, with very clear performance metrics, I wonder if anyone has ever tried making an evolutionary algorithm and if so, how well it would perform. Do we have any idea of how a theoretically perfect algorithm would perform? How much theoretical performance is there to be picked up?

Re: Show HN: Elevators

#386

Post by wrs »

theodorejb wrote: post #353

The worst situation I've encountered is after a large conference when everyone is leaving the hotel at once. An elevator quickly fills up on the way down, but then wastes time stopping at every subsequent floor with a call, even though no one else can fit inside. At each floor the elevator stops, the doors open, the waiting people see it's already packed, the doors close, and this repeats on the next 15 floors before…

I have seen elevators, usually in a big building with a lot of elevators, that do act that way (presumably using weight sensors?). I’ve read that some elevators also have a “kid mode” that does the opposite: if some kid pushes all the buttons as they leave (just for the lolz), the elevator cancels the calls.

Re: Show HN: Elevators

#387

Post by toxik »

liesliy wrote: post #229
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…

The elevator algorithm → disk scheduling connection is such a perfect example of how CS concepts keep showing up in unexpected places. Same idea, completely different domain. It makes me wonder how many other "unrelated" problems we're solving today already have decades-old algorithms waiting to be rediscovered for them. Robot motion planning is basically just elevator scheduling with more degrees of freedom.

> Robot motion planning is basically just elevator scheduling with more degrees of freedom.

Certainly a take, ChatGPT. Not a very good one, but a take nonetheless.

Re: Show HN: Elevators

#388

Post by dredmorbius »

rz2k wrote: post #370
theodorejb wrote: post #353

The worst situation I've encountered is after a large conference when everyone is leaving the hotel at once. An elevator quickly fills up on the way down, but then wastes time stopping at every subsequent floor with a call, even though no one else can fit inside. At each floor the elevator stops, the doors open, the waiting people see it's already packed, the doors close, and this repeats on the next 15 floors before…

There’s also a strategy to jump the line. Say there’s a talk that just took place on the top floor roof deck of a small ~20 floor building. People who don’t want to wait in line with a hundred people, can take the stairs down one level, call the elevator on the way up to enter the car before it is filled, ride it up one level*, and then ride it all the way down to the ground floor. To prevent a riot, the building sho…

Many buildings permit stairwell entry, but limit stairwell exit for fire code (1st) and security reasons (2nd). You'll want to check to see that you can exit at floor n-1 before attempting this, or you'll be riding the stairs all the way down.

Re: Show HN: Elevators

#389

Post by oliv__ »

ImPostingOnHN wrote: post #260
oliv__ wrote: post #240

Earlier quoted context omitted.

I don't see how that's perception then? It was just made inefficient on purpose. If I have to walk to the luggage area 10min and wait another 10min for my luggage it's not the same as if i walk 5min to the luggage area and wait 15min for my bag. Yes, total time is the same but one scenario is acceptable because it feels inevitable and is under control (cannot personally move across space/time faster) the other is not…

The perception angle is: customers are less unhappy waiting the required 20 minutes for luggage to show up, if they're doing something else during that time. In this example, the passengers are still waiting while moving (the wait for luggage is 20 minutes either way), they just don't perceive that portion of the waiting as intolerable. Bringing it home to elevators, the situation is pretty much the same, only in rev…

Sure, but the perception is in accord with reality and in my opinion unchanging since the actual time waiting for luggage has been effectively reduced.

The only difference is the reality has been falsified

Re: Show HN: Elevators

#390

Post by omoikane »

shepherdjerred wrote: post #241
pimlottc wrote: post #232

Earlier quoted context omitted.

This is case where you need to make sure your test data reflects real-world usage or you end up optimizing for the wrong thing. Ideally a new elevator installation would have a trial period where they record usage and then run it through a simulator like this to determine the optimal strategy for that particular building. And you'd want to re-run it every once in a while as the building tenants/usage changes. I wonde…

I wonder if we'll see LLM elevator scheduling

It sounds like you are looking for Happy Vertical People Transporters with Genuine People Personalities.
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