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Where to wait for an elevator (2010)

johndcook.com

91–100 of 115 posts

Re: Where to wait for an elevator (2010)

#91
post #8

Might be a bit off-topic… But: The one big question I have with elevator UX is this: why isn’t it possible to deselect a choice? So pressed 10th floor but wanted 11th. There is no way to press button 10 and then button 11 to correct that mistake. Will I ever solve this mystery?

Every elevator in Korea works this way. Pressing once selects, pressing again deselects.

Re: Where to wait for an elevator (2010)

#92
post #85
post #8

Might be a bit off-topic… But: The one big question I have with elevator UX is this: why isn’t it possible to deselect a choice? So pressed 10th floor but wanted 11th. There is no way to press button 10 and then button 11 to correct that mistake. Will I ever solve this mystery?

I suspect you are thinking like a lawful-good individual engineer. You are solving a niggle, without considering the human and engineering compromises you would discover if you worked in the industry. You are perhaps trying to optimise for a one-person elevator trip, rather than thinking of what is the optimum for a repeated game with many concurrent trip players that includes both cooperator players and defector pla…

Every single elevator in Korea allows you to deselect a floor by simply pushing the button again.

You'd be surprised how often it comes in handy and have never had an issue with anyone deselecting someone else's floor.

Re: Where to wait for an elevator (2010)

#93
post #89
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.

Many elevators in tall buildings have you select the floor when you arrive at the elevator bank, then it assigns you an elevator (usually denoted with letters A, B, C, D etc). When that elevator opens you get in (along with other people who were assigned that elevator), and it will stop at your floor (as well as other floors for other people).

Re: Where to wait for an elevator (2010)

#94
post #8

Might be a bit off-topic… But: The one big question I have with elevator UX is this: why isn’t it possible to deselect a choice? So pressed 10th floor but wanted 11th. There is no way to press button 10 and then button 11 to correct that mistake. Will I ever solve this mystery?

The elevators in my building do support this. People get confused all the time by accidentally deselecting the floor because they didn't notice it was already lit up. Also, the "G" light is broken in one of the elevators, which causes even more confusion (until you realise that it's not broken on the second, lower set of buttons for people in wheelchairs).

Re: Where to wait for an elevator (2010)

#95
post #8

Might be a bit off-topic… But: The one big question I have with elevator UX is this: why isn’t it possible to deselect a choice? So pressed 10th floor but wanted 11th. There is no way to press button 10 and then button 11 to correct that mistake. Will I ever solve this mystery?

Every elevator in Korea works this way. Pressing once selects, pressing again deselects.

Perhaps you could answer the two questions here, preferably relating to a named elevator model: https://news.ycombinator.com/item?id=32005810

And maybe answer my question too: how do blind people know if they are selecting or deselecting?

Watching foreign button-mashers must be amusing!

Re: Where to wait for an elevator (2010)

#96
post #93
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.

Many elevators in tall buildings have you select the floor when you arrive at the elevator bank, then it assigns you an elevator (usually denoted with letters A, B, C, D etc). When that elevator opens you get in (along with other people who were assigned that elevator), and it will stop at your floor (as well as other floors for other people).

Otis has a touch-screen system where you enter the exact destination: https://www.otis.com/documents/256045/11235683/22032_Compass...

Re: Where to wait for an elevator (2010)

#97
> standing at the mean minimizes the average squared distance

This is true, but I find it more intuitive to think about the signed distance: if you define signed_dist(x, y) = x - y, then the mean is the value that makes the average signed distance closest to 0. Of course in reality distance is unsigned – if you walk 1m left then 1m right, you've walked 1m + 1m = 2m, not 1m + -1m = 0m, so the signed distance is not appropriate.

Here is a practical example where the aim is to get the average signed difference to be closest to 0: You want to count a large number of nails by weighing them. To do that, you need to know the weight of a single nail. But the nails have slightly different weights, so you need to pick some representative value. Question: Should you pick the mean or the median? Answer: You should pick the mean, because when you weigh all the nails together the differences will cancel out.

So the rule is:

- To minimise the average value of the absolute difference, pick the median.

- To minimise the absolute value of the average difference, pick the mean.

Re: Where to wait for an elevator (2010)

#98
post #73
post #8

Might be a bit off-topic… But: The one big question I have with elevator UX is this: why isn’t it possible to deselect a choice? So pressed 10th floor but wanted 11th. There is no way to press button 10 and then button 11 to correct that mistake. Will I ever solve this mystery?

> But: The one big question I have with elevator UX is this: why isn’t it possible to deselect a choice? So pressed 10th floor but wanted 11th. There is no way to press button 10 and then button 11 to correct that mistake. In many elevators, one can double-press a button to deselect it.

Now I have a lot of testing in front of me.

Re: Where to wait for an elevator (2010)

#99
post #97

> standing at the mean minimizes the average squared distance This is true, but I find it more intuitive to think about the signed distance: if you define signed_dist(x, y) = x - y, then the mean is the value that makes the average signed distance closest to 0. Of course in reality distance is unsigned – if you walk 1m left then 1m right, you've walked 1m + 1m = 2m, not 1m + -1m = 0m, so the signed distance is not ap…

> But the nails have slightly different weights, so you need to pick some representative value. Question: Should you pick the mean or the median? Answer: You should pick the mean, because when you weigh all the nails together the differences will cancel out.

Well, yes, that is the definition of the mean.

But you can't know what the mean is without having already answered your original question of "how many nails are there?", so as a formal matter this is completely useless advice.

What you actually want to do is pick out a number of nails that you do know exactly, say 10, weigh them, and use the mean weight of that sample to estimate the mean weight of the entire supply of nails.

Re: Where to wait for an elevator (2010)

#100
post #97

> standing at the mean minimizes the average squared distance This is true, but I find it more intuitive to think about the signed distance: if you define signed_dist(x, y) = x - y, then the mean is the value that makes the average signed distance closest to 0. Of course in reality distance is unsigned – if you walk 1m left then 1m right, you've walked 1m + 1m = 2m, not 1m + -1m = 0m, so the signed distance is not ap…

> But the nails have slightly different weights, so you need to pick some representative value. Question: Should you pick the mean or the median? Answer: You should pick the mean, because when you weigh all the nails together the differences will cancel out. Well, yes, that is the definition of the mean. But you can't know what the mean is without having already answered your original question of "how many nails are…

> But you can't know what the mean is without having already answered your original question of "how many nails are there?", so as a formal matter this is completely useless advice.

Yes, obviously you'd estimate the mean/median by taking a small sample (or using a published value). I left that detail out because it's not relevant to the choice between mean and median.

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