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Show HN: Elevators

john.fun

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Re: Show HN: Elevators

#81

Post by hypersoar »

dperfect wrote: post #64
brd529 wrote: post #60

Earlier quoted context omitted.

As the article says, the problem with destination dispatch is that it 'locks in' an elevator. The passenger gets told at call time what elevator to go to, and it can't change that mid flight. RSR has the advantage that the passenger has no idea which elevator will come, and so RSR can change the elevator they will get in real-time as conditions change. This was an insight I had not considered before reading the artic…

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 assignment. Each car will also typically display which floors it's going to when it arrives. I suppose that, rather than assigning a car immediately, you could have passengers check cars as they arrive to see if they're going to their desired floor. Then the system could do reassignment, but people would be scrambling to check every car to see if it's the right one for them, and that's assuming that they understood the system. It would be way too chaotic in practice.

Re: Show HN: Elevators

#82

Post by NooneAtAll3 »

john_strinlai wrote: post #61
alanwreath wrote: post #45

Earlier quoted context omitted.

I wish there were more games like this. It’s such a simple premise but so satisfyingly difficult after each level. And it even has a bit of randomish failure which makes for even more challenge.

at a quick glance, it reminds me of "the farmer was replaced", if you havent seen/heard of that one

https://store.steampowered.com/app/2060160/The_Farmer_Was_Re...

I remember this one, it deserves all sorts of praise

Re: Show HN: Elevators

#83

Post by dbcurtis »

orliesaurus wrote: post #4

Oh my god, every time I'm waiting for the elevator, I think of how annoying it must be to be someone who's building the algorithm to make sure that you minimize the amount of wait times between picking up people and taking them to their destination. Then I also wonder if the people who apply the logic and program the logic into the elevators are actually evil sadists that are doing it on purpose to make us wait longe…

I have done several third-party elevator integrations (software that talks to the elevator controller) for coordinating other equipment with the elevator. One thing that always struck me once I had full visibility into the location and motion of all the elevator cabs is how busily they are scheduled. Waiting in the elevator lobby for a cab seems to take forever, but viewed from the dispatch side, it is a flurry of activity and cabs are rarely idle during any hours the building is normally occupied. It is easy to nerd out just watching the status panel.

Another thing I learned: If an elevator mechanic says: "I'll meet you first thing in the morning." He means something like 4:00AM. They want to get in and out before people start arriving to start their day.

Re: Show HN: Elevators

#84

Post by taftster »

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…

Yes, it's definitely more likely for an individual already in an upper floor to return to ground than a stop above or below. The people queuing up in simulations don't seemingly get this right all the time.

Also the group of people going to or returning from lunch is real as well. The grouping factor happens more at the middle of the day and less at the morning or evening. Primarily because of lunch.

Re: Show HN: Elevators

#85

Post by jhallenworld »

What this doesn't include: not all people are equal. Do you want the CEO of your new office building to have to wait behind a bunch of plebeians? At least one car is going to have to be reserved for the better people.

Re: Show HN: Elevators

#86

Post by dbcurtis »

orliesaurus wrote: post #4

Oh my god, every time I'm waiting for the elevator, I think of how annoying it must be to be someone who's building the algorithm to make sure that you minimize the amount of wait times between picking up people and taking them to their destination. Then I also wonder if the people who apply the logic and program the logic into the elevators are actually evil sadists that are doing it on purpose to make us wait longe…

One other thing to add: It isn't the elevator scheduling software being obtuse, that software gets a huge amount of thought. But elevators are expensive, and building owners do not over-spend on a whim. Typically, they have just enough cabs (if that) to handle the expected load.

Re: Show HN: Elevators

#87

Post by stackskipton »

Sohcahtoa82 wrote: post #59
Waterluvian wrote: post #10

Makes me want to play Sim Tower again. There’s something so satisfying about watching a machine just dutifully work through queued tasks like this.

If you liked SimTower, Project Highrise is worth taking a look into. https://store.steampowered.com/app/423580/Project_Highrise/

Project Highrise doesn't have elevator simulation. Elevator is just portal that teleports the sim to proper floor.

Re: Show HN: Elevators

#88

Post by superhuzza »

the_af wrote: post #65
esperent wrote: post #40

Earlier quoted context omitted.

I've never seen anyone do this anywhere in the world including Italy. I've never been to China but wouldn't you learn quickly after getting in an elevator going the wrong way not to do that again? The only exception I can see if there's way more people than elevators and you just need to get spot at all costs.

My wife always randomly hits the up or down button, then gets upset if I explain why she should only pick the one she really wants. She forgets the next time. I think some people never really understand how elevators work. See also: the keep open / close doors button. I had one building administrator explain to me we should add a delay of 10 seconds to the "quickly shut door" button because otherwise she kept getting…

I fear in both cases, its not a lack of understanding of elevators but of common sense...

Re: Show HN: Elevators

#89

Post by dbcurtis »

neutronicus wrote: post #21
orliesaurus wrote: post #4

Oh my god, every time I'm waiting for the elevator, I think of how annoying it must be to be someone who's building the algorithm to make sure that you minimize the amount of wait times between picking up people and taking them to their destination. Then I also wonder if the people who apply the logic and program the logic into the elevators are actually evil sadists that are doing it on purpose to make us wait longe…

They might have other objective functions like wear-and-tear on the elevators, total energy usage, or something

It's pretty much throughput. The cap-ex of a single cab swamps any other cost, so the only way to reduce total number of cabs is optimizing for throughput.

Re: Show HN: Elevators

#90

Post by hasteg »

Lol, love this post. Every single day when I take the elevators at the office I try and figure out what the algorithm is behind it. Been too lazy to just research it. Now I know!
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