

Elevator Expertise from an Expert - danw
http://www.subtraction.com/archives/2007/0913_elevator_exp.php

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danteembermage
This reminded me of a keynote speech at the dynamical systems conference at
Snobird a few years back about the limits of computational mathematics, i.e.
the human limits of asking the wrong question.

The aged speaker was apparently a consultant for the British transportation
authority; they wanted a model that would optimize their highway expenditure
to put the money where it would do the most good along multiple criteria, time
on the road, overall budget effects, safety, etc.

The team spent a significant amount time getting all the dynamic pieces of the
model to interact and then started running solutions. Strangely though, no
matter what reasonable weights or parameters they threw at it, it always
recommended pedestrian safety expenditure of zero.

After a lot of puzzling they finally figured out what was going on. You see, a
significant portion of the pedestrians on English crosswalks were aged
pensioners. Since the model incorporated overall budget effects into its
preferences, every dollar spent on pedestrian safety lead to the decreased
risk of accidental death of net-revenue-drain individuals, i.e. little old
ladies walking to the corner shop. So the models did an excellent job of
solving the wrong problem, GIGO.

Likewise, actual time spent from start to finish is most definitely not the
same at perceived time from start to finish, with the second probably being to
most important. Which, in case you didn't know, is why hotel elevators almost
invariably have mirrors on either side of the door, you reflection gives you
something to do other than thinking about how long your elevator is taking, a
considerably cheaper solution than trying to solve the computational problem
of maximal overall trip efficiency.

That said I'm totally jealous they get paid to play with that problem. If I
were there I'd be like the guys in the arm chairs from the Collins College
advertisements doing the "dude, I can't believe we get paid to play games!"

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neilc
Wow, that's very cool -- I remember thinking about elevator scheduling in the
past as an interesting theoretical problem. Scheduling algorithms for taxis,
bus services, and similar systems is another related problem that seems
interesting. A friend of mine spent some time writing software and setting up
a small compute cluster to solve variants of the traveling salesman problem
for a courier service.

More broadly, I think there are many situations in which CS can be applied to
yield an incremental improvement in some every-day task where the standard
solution is perfectly reasonable, but could be made by efficient by an
intelligent algorithm. As the cost of building in these algorithms continues
to decrease (and as WiFi + RFID becomes more pervasive), the number of
problems for which it will be feasible to apply a sophisticated solution will
continue to increase. An incremental improvement in a single elevator's
dispatch time might not mean all that much, but when it's applied to tens of
thousands of elevators that operate every day, that's a nice productivity
hack.

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Tichy
I think that notion of "experience design" is very important, and that
people's perception might differ from reality. Like I think I have heard that
Menus are actually faster on Linux than on Windows, but on Windows it feels
faster because they are animated immediately.

I also read somewhere of a case where designers solved the waiting problem by
putting up mirrors next to the elevators. That way, people were busy looking
at themselves and didn't notice the wait time as much.

~~~
fnord123
>but on Windows it feels faster because they are animated immediately.

Context menus take between 3 and 6 seconds on my Windows XPSP2 machine to load
the desktop context menu as it thrashes the hard drive. That's after a memory
upgrade where it took half a minute to load the desktop context menu. My
slower KDE machine loads context menus instantly.

Where are these Windows machines with instant animating menus?

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edw519
"it's the intangible quality of what users are experiencing that becomes the
toughest nut to crack"

Good thing Microsoft isn't in the elevator business.

Imagine what a splash screen would look like.

