Where to wait for an elevator (2010) • Hacker News Board

Re: Where to wait for an elevator (2010)

#111

Post by thaumasiotes » Thu, Jul 07, 2022, 12:50 PM UTC

Fatnino wrote: post #89

h4waii wrote: post #63

Earlier quoted context omitted.

Leave the button recessed after it's been selected, even if the LED fails (how often does this actually happen?) it's still a visual and tactile indicator. To deselect the floor, simply press in again.

Remove the buttons entirely and replace with a QRcode/NFC thing where each rider can vote/unvote where he personally wants to go. This can also work outside before the elevator arrives so a routing system can decide to bundle up a bunch of people going to the same floor in one express elevator. Haven't thought out how the ux would look to keep the wrong people out of that one elevator.

> Remove the buttons entirely and replace with a QRcode/NFC thing where each rider can vote/unvote where he personally wants to go.

My local pizza place plays music based on customer voting through a smartphone app. It's not necessary to be there in order to vote - you just need the app.

This elevator design could be fun in similar ways.

Re: Where to wait for an elevator (2010)

#112

Post by hddqsb » Thu, Jul 07, 2022, 1:12 PM UTC

thaumasiotes wrote: post #109

hddqsb wrote: post #105

Earlier quoted context omitted.

I was trying to come up with a scenario where you have to choose between the mean and the median, and the correct choice is the mean due to signedness (in contrast with the elevator example, where the correct choice is the median because the distance is unsigned). Do you have a better example? It should be obvious that the mean is the correct representative value for weighing nails. My point is that there are cases t…

It is an interesting example, but after some thought it's basically identical to the elevator example. It is so similar that I have some doubts about whether I could correctly extrapolate a principle based on those two examples. > Why is the mean the correct representative value for counting nails, but not for minimising fines? I'm arguing that it's because when the nails are weighed together the errors are signed, b…

> You're relying on the assumption that, in the above example, the fine (which should be minimized) is directly proportional to difference from the estimate. But that assumption doesn't appear in the explanation of why one metric or the other will minimize the fine.

Yes, my argument is specifically for the case where the fine etc. is directly proportional to the difference (or absolute difference). I'm pointing out that the two cases are similar apart from the signedness.

To put it mathematically, I'm just observing that if you have a set {x_i}, then:

- avg{|x_i - y|} is minimised by setting y to median{x_i}

- |avg{x_i - y}| is minimised by setting y to avg{x_i}

The excerpt in the article says "the mean minimizes the average squared distance" (i.e. setting y to avg{x_i} minimises avg{(x_i - y)^2}), which is correct but not obvious (the proof is non-trivial, and if you were to ask the students who chose the mean why they chose it I bet none of them would say "because it minimises the squared distance"). So I find it odd to include that statement. If I was the author I would have said "the mean minimizes the average signed distance", which I find more intuitive and think is a better explanation of why those students chose the mean. (Also, I like how "average value of the absolute difference" and "absolute value of the average difference" are the same words just in a different order.)

Re: Where to wait for an elevator (2010)

#113

Post by remram » Thu, Jul 07, 2022, 1:38 PM UTC

h4waii wrote: post #63

Swenrekcah wrote: post #56

Earlier quoted context omitted.

This comment right here is an example of thinking like a good designer. No amount of sleek surfaces and cool lighting can beat this.

Leave the button recessed after it's been selected, even if the LED fails (how often does this actually happen?) it's still a visual and tactile indicator. To deselect the floor, simply press in again.

Now you made the buttons even more complicated, requiring some sort of magnet or motor in addition to a simple LED. And what do you do when that fails?

Re: Where to wait for an elevator (2010)

#114

Post by remram » Thu, Jul 07, 2022, 1:41 PM UTC

spogbiper wrote: post #51

deathanatos wrote: post #45

Earlier quoted context omitted.

I didn't think elevators permitted scenario 1 to occur at all; I thought they refused to allow selecting floors not in the direction of travel. (I don't usually board elevators traveling in the wrong direction, ofc., so, I'm not that sure.)

The one in my building will allow you to select any floor at any time. it always goes to the last stop in the current direction before reversing as far as i have noticed

I've experienced both kinds of elevators. Some don't let you select a floor that's in the wrong direction, so you can notice you entered the wrong elevator and get back out.

Re: Where to wait for an elevator (2010)

#115

Post by Fatnino » Thu, Jul 07, 2022, 6:52 PM UTC

thaumasiotes wrote: post #111

Fatnino wrote: post #89

Earlier quoted context omitted.

Remove the buttons entirely and replace with a QRcode/NFC thing where each rider can vote/unvote where he personally wants to go. This can also work outside before the elevator arrives so a routing system can decide to bundle up a bunch of people going to the same floor in one express elevator. Haven't thought out how the ux would look to keep the wrong people out of that one elevator.

> Remove the buttons entirely and replace with a QRcode/NFC thing where each rider can vote/unvote where he personally wants to go. My local pizza place plays music based on customer voting through a smartphone app. It's not necessary to be there in order to vote - you just need the app. This elevator design could be fun in similar ways.

Yeah, that's why I added NFC to at least approximate presence.