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Show HN: Elevators

john.fun

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Re: Show HN: Elevators

#121

Post by bherms »

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…

We did this in college as well using microcontrollers and leds or something - i forget the exact details. It was super fun

Re: Show HN: Elevators

#122

Post by lefra »

fellowniusmonk wrote: post #73
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…

I think the problem with simulations like this is that it doesn't include the chaos of innatentive humans. Forcing functions that dump people into well defined funnels can have such a high net positive effect it more than makes up for theoretical losses. It's like narrow, hard road bike tires losing performance because of deflection from rough road surfaces and how long it took designers to factor that in to real bik…

Kind of like airplane boarding. The ideal algorithm would be to make people board from back to front, and from window to aisle. However, people are not disciplined enough to strictly sort themselves, they won't all take the same time to sit, and some people want to board together (family with children for example).

Apparently, the fastest known way to fill up a plane in real-life conditions is to let people board in random order, without pre-assigning a seat.

Re: Show HN: Elevators

#125

Post by wlesieutre »

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.

A fun tidbit about Sim Tower:

> After my lecture, a Maxis employee who shall remain nameless buttonholed me. "You guessed right," she said. "Sim Tower was built around a real elevator simulation program we bought from a Japanese guy."

https://web.archive.org/web/20090916193335/http://www.gamasu...

Re: Show HN: Elevators

#126

Post by gene91 »

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…

In some places, I see people do that. It’s not stupidity. I learned the logical reason after observations. During busy hours in some busy buildings, there isn’t enough elevator capacity. Therefore, if you want to go down to the ground floor, taking a trip up and then down might be better (a less-bad worst case outcome, or even a better average outcome) than waiting for a non-full downward elevator. In such case, it’s logical to press both up and down.

Re: Show HN: Elevators

#127

Post by Aunche »

Our building installed destination dispatch system to their elevators and it seems to help overall. However, it breaks when say a team wants to get lunch together, but only one person presses the elevator button. The elevator thinks that it can keep on accepting new passengers so it stops at floors even though it's already full.

Re: Show HN: Elevators

#128

Post by NooneAtAll3 »

ivolimmen wrote: post #93
NooneAtAll3 wrote: post #82

Earlier quoted context omitted.

https://store.steampowered.com/app/2060160/The_Farmer_Was_Re... I remember this one, it deserves all sorts of praise

I can also recommend https://store.steampowered.com/app/375820/Human_Resource_Mac...

and its sequel is also worth a mention https://store.steampowered.com/app/792100/7_Billion_Humans/

but imo, unlike farmer, these games reaaaaly lack the ability to make functions/subroutines

manually doing all the goto loops becomes tiring

Re: Show HN: Elevators

#129

Post by cruffle_duffle »

dbcurtis wrote: post #86
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.

Not only that but different countries have code regimes that make more elevators especially expensive. See how building codes in the US basically ensure there are only two real manufacturers in the market vs a healthy ecosystem in others: https://youtu.be/Or1_qVdekYM

Re: Show HN: Elevators

#130

Post by psadri »

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 gate to the luggage carousel and waited x mins for the first bag → unhappy. Then the airport decided to add a long, round-about "walk" path from the gate to the luggage area that burned some of those minutes → same total "wait" but happier passengers.

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