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Show HN: Elevators

john.fun

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Re: Show HN: Elevators

#361

Post by dsego »

akoboldfrying wrote: post #320
dsego wrote: post #314

In my residential building we have two elevators, a big one and a small one, the small one can fit 3-4 people if they squeeze together, it can't fit a bicycle. And of course, they don't work independently, so if the small one is already on your floor the big one won't stop there, so if I have my bicycle with me, I need to send the small one to a higher floor first, and since people are using the lifts constantly, som…

This is hilarious. But I'm also thinking: Maybe just use the stairs? Your bike suggests you aren't afraid of a little cardio.

8 stories

Re: Show HN: Elevators

#362

Post by Gabrys1 »

esikich wrote: post #220
vova_hn2 wrote: post #177

Earlier quoted context omitted.

> Is it because the criteria is wait time not travel time? Yeah, it doesn't make any sense to optimize wait time instead of total time from pressing the button to reaching destination.

It very well could be the case that people get more upset about waiting for the car than total travel time when they are already in the car. Ie, pick them up sooner even if travel time is longer. In fact, I would bet that this is the case.

It should be both, I think. Same goes for queuing in the restaurant. Waiting for the table for 5 minutes, then 5 minutes for the waiter, then 10 minutes for the drink, then 25 for the food is better than waiting for the table for 25 and then getting your full order in another 5.

Basically you have an irrational sense of progress even if things get delayed

Re: Show HN: Elevators

#363

Post by psadri »

ericpauley wrote: post #337
psadri wrote: post #130

Aside for the algorithms and how well they work, there is a psychological aspect to how people perceive "wait" times. It turns out just waiting is very annoying. But having people do anything during that same wait period → perceived as progress → not upset. An example iirc was waiting for luggage at the airport. It takes min of x minutes for the first bags to show. In one version, passengers went directly from the ga…

This story is shared all the time, but what airport actually did this? I’m not aware of any major US hub that meaningfully delays passenger egress like this.

To be honest I also just read about it. However everytime I pass through Heathrow I think someone really took the idea to heart.

Re: Show HN: Elevators

#364

Post by swiftcoder »

Ekaros wrote: post #330
shepherdjerred wrote: post #241

Earlier quoted context omitted.

I wonder if we'll see LLM elevator scheduling

Most likely not. I think all the big players have been using more traditional ML approaches for years. Then again someone new might go there and fail miserably.

This is an industry that evolves extremely slowly. A decade back one of the big players in this space was still using a software emulation of their original hardware relay logic, because it was cheaper than retraining all the technicians...

Re: Show HN: Elevators

#365

Post by airbreather »

Great article.

Where I live, on the taller buildings it is common to have banks of elevators which only service certain floors, eg floors 2:25 and 26-50 are two different banks of elevators.

Some modern elevators have two cars per shaft, imagine scheduling that.

Re: Show HN: Elevators

#366

Post by Ekaros »

swiftcoder wrote: post #364
Ekaros wrote: post #330

Earlier quoted context omitted.

Most likely not. I think all the big players have been using more traditional ML approaches for years. Then again someone new might go there and fail miserably.

This is an industry that evolves extremely slowly. A decade back one of the big players in this space was still using a software emulation of their original hardware relay logic, because it was cheaper than retraining all the technicians...

It is just the reality that LLMs are not superior for this purpose. They are most likely very much inferior. There is no need to use language models for something that involve no language.

I feel weirded each time LLMs are suggested for anything as some sort of holy solution for every single problem. Robot surgery let LLM control it. Robots cooking LLMs. Nuclear power plants and oil refineries LLMs... Industry has find a sledge hammer and now everything is a nail...

Re: Show HN: Elevators

#367

Post by sambellll »

richk449 wrote: post #360
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…

It is almost certainly because of the way the simulation was performed: It turns out these fancy kiosks are in general worse for wait times compared to the traditional good ol' up and down buttons. There are certainly edge cases when the kiosks can win out (extremely tall buildings with 8+ cars per elevator bank) but for the majority of cases, simple up down buttons reign supreme. This counterintuitive result is all…

> Seems like the real reason it performed worse in this simulation is that when they implemented destination dispatch, they assigned an elevator at time of request, and had no system for reviewing and updated that assignment.

I don't think it's possible to have destination dispatch AND update assignment together, in the real world.

- If the user clicks floor 26 and you tell them to wait at elevator G, you can't really tell them to move to F if it's taking too long.

- But if you don't tell them an elevator to wait at, then you'd need them to run around what is possibly like 5-8 elevators to find which one is going to their floor? That's obviously not realistic.

So then you're going to just have them get in the first one that opens? But then that's just the same as an up/down button.

Re: Show HN: Elevators

#368

Post by Neywiny »

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

Re: Show HN: Elevators

#369

Post by newtwentysix »

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…

OMG ! This is a huge problem in India. Frustrating.

Re: Show HN: Elevators

#370

Post by rz2k »

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 should probably deploy an employee with a fire key to manually operate the elevator.

* Elevators will answer an up button call while it is going to meet a down call from the top floor, but they will answer that call before filling any new down instructions, so you do have to ride to the top first.

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