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One Cool Day Job: Building Algorithms For Elevators

timothy posted about 2 years ago | from the getting-it-up-is-only-half-the-battle dept.

Math 203

McGruber writes "The Wall Street Journal has an article about Theresa Christy, a mathematician who develops algorithms for Otis Elevator Company, the world's largest manufacturer and maintainer of people-moving products including elevators, escalators and moving walkways. As an Otis research fellow, Ms. Christy writes strings of code that allow elevators to do essentially the greatest good for the most people — including the building's owner, who has to allocate considerable space for the concrete shafts that house the cars. Her work often involves watching computer simulation programs that replay elevator decision-making. 'I feel like I get paid to play videogames. I watch the simulation, and I see what happens, and I try to improve the score I am getting,' she says."

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maybe they should release it as a game (5, Funny)

Trepidity (597) | about 2 years ago | (#42156199)

'I feel like I get paid to play videogames. I watch the simulation, and I see what happens, and I try to improve the score I am getting,' she says.

I've been looking for a more sophisticated follow-up to SimTower for a while now. I'd buy Otis Elevator Tycoon.

Re:maybe they should release it as a game (1)

Anonymous Coward | about 2 years ago | (#42156399)

You got modded funny, but SimTower was an awesome game and I totally agree with you.

Re:maybe they should release it as a game (3, Interesting)

westlake (615356) | about 2 years ago | (#42156413)

I've been looking for a more sophisticated follow-up to SimTower for a while now. I'd buy Otis Elevator Tycoon.

This gets modded up as a joke, but the interaction of tech and people within a mega-structure seems to me a solid foundation on which to build a game. But I can think of only Sim Tower and Startopia as examples.

Re:maybe they should release it as a game (0)

Anonymous Coward | about 2 years ago | (#42156451)

It would be a great android/iphone game. A bit like sushi chef games.

Re:maybe they should release it as a game (3, Interesting)

plover (150551) | about a year ago | (#42156799)

Actually, long ago I remember reading the story of SimTower, and it actually started out as an elevator simulator research tool! It turned out that the simulator was so much fun to play that someone had the bright idea to morph it into a video game.

Re:maybe they should release it as a game (3, Informative)

T-Ranger (10520) | about 2 years ago | (#42157869)

I'm not sure about that, but the original Sim City *was* based on Will Wight's previous project, Raid on Bungeling Bay. Or rather, how his Bungeling Bay map editor was as much fun as the end game.

Re:maybe they should release it as a game (5, Informative)

the_rajah (749499) | about a year ago | (#42157263)

I designed the hardware and wrote the code for a much smaller elevator company for 25 years... All written in assembly language running on an 8085 CPU with 256 bytes (Yes, bytes) if RAM and 8K bytes of EPROM. It doesn't take much to handle the basics when you're using assembly language. I've done up to 26 stops in a multi-car group with that setup. Each elevator is independent and can run on its own, but they communicate with each other to handle dispatching so multiple cars coordinate their activity.

Optimizing is worthwhile, but adds a lot of complexity. You have to take into account for car locations, direction, speed, where car and hall calls are locatedand have to figure in such things as door times to calculate which car can service a hall call soonest.

As the author says, it's a set of interesting problems and I've had fun with it. Yes, the equipment I designed and wrote the software for is obsolete now, but there's a lot of it out there so I'm anticipating writing updates for a while longer as I head toward eventual retirement.

Re:maybe they should release it as a game (4, Informative)

anubi (640541) | about a year ago | (#42157699)

I sure wish cities would hire guys like you to work on their traffic lights.

I highly question whether or not anyone pays any attention at all to the timings of these things; It seems that they would have more luck getting anyone who has ever milked a cow to design one, as they would have some inner sense as to how timing results in smooth flow. Improperly time your efforts and you get no milk and infuriate the cow.

( You can tell where I was raised here ).

Harddisks use something like it (1, Interesting)

Anonymous Coward | about 2 years ago | (#42156255)

https://en.wikipedia.org/wiki/Elevator_algorithm [wikipedia.org]

* Thought that might "pique" a few folks' interests...

APK

P.S.=> However - I'd wager that MOST of you know about this though... Especially the "hardware heads" into hard disk drives!

... apk

Re:Harddisks use something like it (0)

Anonymous Coward | about 2 years ago | (#42156307)

I'd wager that MOST of you know about this though

This is a statement I thought I'd never see on Slashdot. You must be new here.

Re:Harddisks use something like it (4, Interesting)

Sir_Sri (199544) | about a year ago | (#42156623)

That's an undergraduate level general optimization problem.

The one in TFA is a graduate level optimization under a particular set of data constraints. So the generally optimal algorithm for elevators has to a assume a random distribution of people to be picked up and destination floors (head is in a random location wants data from some other random location) - but in practice you may be need sequential access or the like. With elevators, I would expect that in mornings in residential buildings people want to empty out so the 'resting' point would to close to 2/3rds or 3/4ths of the way up, but in the evenings it would be the reverse direction, and business would be the reverse of residential. Schools have a somewhat more random use of bursty every hour up and down, and really big businesses may want dedicated elevators between floors shared by particular companies because there's a lot of daily movement within the floors of a company but not so much outside their area.

Lunch of course adds another complication.

There's a lot of neat work into simulating the data for a building that doesn't exist yet, or measuring the data for a building that exists but has a bad algorithm. And then trying to tailor your elevator to the specific behaviours that actually exist.

Re:Harddisks use something like it (0)

Anonymous Coward | about a year ago | (#42156851)

Nevertheless it's similar and has variants that work better in different scenarios/circumstances. Your point's what?

Re:Harddisks use something like it (1)

Anonymous Coward | about a year ago | (#42157535)

To describe the particulars of this problem that go beyond the well-known elevator algorithm.

I know it's the Internet, but still. Don't be a jerk.

Re:Harddisks use something like it (3, Interesting)

ShanghaiBill (739463) | about a year ago | (#42157487)

So the generally optimal algorithm for elevators has to a assume a random distribution of people to be picked up and destination floors

It seems to me that assuming a poisson distribution [wikipedia.org] ) or other random distribution, is a bad assumption. Passengers would be likely to arrive in clumps as meetings ended or buses arrived, and some destination floors would be far more popular than others

One thing that would help, but I have never seen, would be a way to cancel a button push (either the call button, or a floor button inside the elevator). Buttons are often pushed in error, resulting in wasted time.

I once heard a funny story about an engineer assigned to optimize an elevator system. The building supervisor had received numerous complaints about the elevator delays, so he told a young engineer to fix the problem. The engineer tried several adjustments, but still had just as many complaints. So he had mirrors installed next to each elevator, so people could adjust their hair, tie, clothing or whatever while they were waiting. Since people now had something to do while they were waiting, most of the complaints stopped.

Re:Harddisks use something like it (1)

Sir_Sri (199544) | about 2 years ago | (#42157845)

It seems to me that assuming a poisson distribution [wikipedia.org]) or other random distribution, is a bad assumption.

it definitely is a bad assumption.

But if you are trying to solve the general problem of where to position an elevator or a disk head in general you have to. That's why it's an 'undergraduate' level problem. The serious research today comes in knowing what the real data will be like, and whether or not you can optimize for real data rather than an average best case for any arbitrary data set.

Well, the ONLY diff. I see? (3, Interesting)

Anonymous Coward | about 2 years ago | (#42158041)

Is that the resting place of the diskdrive head probably doesn't vary (like you describe for start of workday, lunch, & of course, quitting time - moving it to the most optimal spots during certain daily time periods).

Afaik? The HDD tends to try to keep the read-write heads in the CENTER of the disk (or rather, center of the filemass (moved to outermost fastest tracks with defraggers for fastest access/seek due to larger rotational diameters)).

You can't "move" the MFT$ (master file table) & certain other system files during usermode after all!

(At least NOT during usermode access to accomodate for times it *MIGHT* be different for differing work patterns (say you work @ home, & do your work the 1st 8 hours you wake up, & then the rest is family usage, your leisure, etc./et al)).

However, with NTFS & probably other modern filesystems?

MFT$ is placed in the MIDDLE of the "filemass" though for "optimality", since it's needed for file accesses of any kind (time of access stampings too, etc.) & then binary search patterns (like NTFS uses in b-tree seeks) do the rest!

I find this algorithm pretty amazing & VERY "common-sense", & that elevator algorithm & its variants, do one hell of a good job on QUEUEING UP REQUESTS, & then issuing them in the order the disk drive head passes over the areas concerned, in the most efficient order possible.

1 of its variants use 2 buffers (1 = currently being serviced requests, & 2 = upcoming requests to service): THIS seems like the smartest way to go about it imo @ least.

* Anyhow/anyways - I didn't think you were being a jerk, I hope you feel the same way regarding myself...

(Actually? I thought you offered some decent enough points, but you MUST ADMIT, the algorithms here are AMAZINGLY similar & I didn't SAY they were the "exact same" either)

Plus - I'd wager since the one for HDD's is named "Elevator Algorithm", the harddisk folks GOT THE IDEA from folks like this lady!

APK

P.S.=> Lastly - Sorry: Not "graduate level student"/postgrad/postdoc etc., in CSC!

I got the AAS 60 credit hours outta the way & went to work in the field as a programmer back in 1994 onwards!

(I've been "chipping away @ the stone" since then, & am 90/120 credit hours into the B.S. in CSC currently, taking coursework here and there as time & money permit)...

... apk

Sounds good but . . . (5, Funny)

Anonymous Coward | about 2 years ago | (#42156269)

I expect the job has its ups and downs just like any other.

Re:Sounds good but . . . (0)

Anonymous Coward | about 2 years ago | (#42156311)

As long as she doesn't fall to pieces, she'll survive.

Re:Sounds good but . . . (5, Funny)

Hognoxious (631665) | about 2 years ago | (#42156327)

Careful, I hear it's easy to get shafted.

Re:Sounds good but . . . (2)

davester666 (731373) | about a year ago | (#42156557)

Just don't push her buttons!

Re:Sounds good but . . . (0)

Anonymous Coward | about 2 years ago | (#42156437)

You can't put a whole profession in a box.

Re:Sounds good but . . . (2)

Delarth799 (1839672) | about a year ago | (#42156675)

Sometimes you need to think outside of the box

Re:Sounds good but . . . (0)

Anonymous Coward | about a year ago | (#42156705)

I bet she freaks out when a VIP arrives to the building that she is working on.

Re:Sounds good but . . . (2)

SeaFox (739806) | about a year ago | (#42157537)

Yes, but for every door that closes, a new one opens elsewhere.

Code that must "never crash", no? (2, Insightful)

dryriver (1010635) | about 2 years ago | (#42156273)

I'm guessing that the hardest part of the job is writing code that does not crash, possibly leaving elevator riders stranded between floors, or going up when they want to go down. Over the years Otis must have developed a pretty good elevator usage simulator that plays through millions of possible elevator use scenarios, and tries to find one that either crashes or confuses the system. If yes, the developers responsible for that "possibility simulator" should have been named in the article alongside "The Elevator Algorithm Lady". They should have gotten some credit where credit is due...

Re:Code that must "never crash", no? (4, Informative)

Anonymous Coward | about 2 years ago | (#42156323)

News flash: State machines don't crash.

Re:Code that must "never crash", no? (3, Informative)

Anonymous Coward | about 2 years ago | (#42156389)

She probably just writes the logic part not the code that realizes that logic. The actual code will be a finite state machine with certified logic blocks. Those dont crash.

Re:Code that must "never crash", no? (4, Informative)

Animats (122034) | about 2 years ago | (#42156421)

Each elevator has its own controller, which is relatively simple. When there's more than one elevator, there's also a group controller, which makes the decisions about which elevator responds to which call. All the smarts are in the group controller.

Many elevators have a key switch for "independent service", which disconnects them from the group controller. Then they only respond to the buttons in the car. The group controller isn't necessary to basic elevator operation.

Re:Code that must "never crash", no? (2)

amorsen (7485) | about a year ago | (#42156615)

Elevator software is probably the most obvious use case for software with correctness proofs. Note that the elevator going up when you want to go down is not necessarily bad programming, the most efficient place to go next is not necessarily where the last person who entered the elevator wants to go.

Re:Code that must "never crash", no? (1)

Lehk228 (705449) | about a year ago | (#42156657)

it really just needs a very simple core of functions certified and an interface that less tested code can use to control it.

parts that need to be a certified finite state machine

detect when at a floor and open doors only at safe times (when stopped at a floor unless overridden by fire key) and detect when car is over weight limit detect when fire alarm is active

parts that need to be really damned good code: always travel to specified floor number

parts that can be done with PHP and javascript if you want: deciding what order to go in to maximize effectiveness, if it gets it wrong worst case scenario is people get pissy and use the stairs, burn some calories

Re:Code that must "never crash", no? (1)

the_rajah (749499) | about a year ago | (#42157361)

I did all my elevator in assembly language, Sonny. (Seriously) Now get off my grass.

We don't use the term "crash" when talking about elevators.

Re:Code that must "never crash", no? (0)

Anonymous Coward | about a year ago | (#42157031)

Note that the elevator going up when you want to go down is not necessarily bad programming, the most efficient place to go next is not necessarily where the last person who entered the elevator wants to go.

Most elevators I've seen have a pair of lamps on each floor that show the direction the elevator will go next. If you push the down button but the door opens with the up lamp on, you just don't get on (unless you like spending extra time in an elevator with other people).

Re:Code that must "never crash", no? (1)

davidbrit2 (775091) | about 2 years ago | (#42157777)

If it's anything like traffic lights, there's probably an independent controller/program to watch for invalid states, and immediately disable the fancy logic and switch to a simple failsafe mode. Honestly, the demands are probably less than with traffic lights. (Bad green lights could kill people, but an indecisive elvator would probably be a nuisance at worst.)

If (hospital elevator) (1)

GoodNewsJimDotCom (2244874) | about 2 years ago | (#42156279)

If(weight in elevator if(almost every floor pressed)
{
emit_audio_tone("Hey kid cut that out, people's lives might be at stake because you're playing in a place you shouldn't be playing.");
call_security("Kid pressed all the elevator floor again, go embarrass him to his parents.");
clear_all_floor_buttons();
}

Re:If (hospital elevator) (1)

GoodNewsJimDotCom (2244874) | about 2 years ago | (#42156293)

if(weight in elevator less than 200) My less than symbol got nixed because it was thinking I meant hypertext markup

Re:If (hospital elevator) (3, Interesting)

GoodNewsJimDotCom (2244874) | about 2 years ago | (#42156303)

I just realized something else, everyone would be playing with the elevator even more if it talked to you... so maybe it isn't a good thing to emit a sound... Maybe just call security.

Re:If (hospital elevator) (2)

tftp (111690) | about a year ago | (#42156535)

My less than symbol got nixed because it was thinking I meant hypertext markup

You are welcome to use this one: < (written as &lt; - all four characters required.)

Re:If (hospital elevator) (0)

Anonymous Coward | about 2 years ago | (#42156353)

Most hospitals have multiple sets of elevators and one or two are reserved for patient transport.

Mathematician? (4, Insightful)

hawguy (1600213) | about 2 years ago | (#42156287)

Was a mathematician really needed for this job:

During the recent $550 million upgrade of the Empire State Building, Ms. Christy was asked whether she could help get more people up to the observation deck. She said she couldn't get more people into a car but could move them up more quickly. So she increased the elevators' speed by 20%, to 20 feet per second. Now the cars can rise 80 floors in about 48 seconds, 10 seconds faster than before.

Isn't making the elevator go faster a job for an engineer? Does one really need to be a mathematician to know that a faster elevator moves people faster?

Re:Mathematician? (0)

Zontar The Mindless (9002) | about 2 years ago | (#42156337)

Velocity and frequency are not the same thing, and 'faster' does not necessarily mean 'more frequently'.

MLT, fuckhead (1)

Hognoxious (631665) | about 2 years ago | (#42156383)

'faster' does not necessarily mean 'more frequently'.

It certainly doesn't when it's expressed in feet per second.

In the elevator trade... (1)

the_rajah (749499) | about a year ago | (#42157341)

We rate elevator speeds in feet per minute. A typical small hydraulic elevator will run 100 FPM. A high-rise express car may get up to 1,500 FPM.

Re:In the elevator trade... (1)

inode_buddha (576844) | about 2 years ago | (#42158009)

Wow -- those kinds of speeds make me wonder about the air venting that must be required at the top and bottoms of the shafts. Thats amazing!

Re:Mathematician? (1)

MachDelta (704883) | about 2 years ago | (#42156355)

Should be a CS job, really. All you need to do is modify the speed-up loop. [thedailywtf.com]

Re:Mathematician? (1)

Hognoxious (631665) | about 2 years ago | (#42156359)

It might be one of those weird things where the faster it's going the longer it takes to come to a stop, so going faster makes sense if there are calls from fewer floors but not if someone wants to board at every one. Or something.

We actually use different speeds for... (1)

the_rajah (749499) | about a year ago | (#42157327)

single floor runs and for multi-floor runs. Yes, the faster the car is running, the longer the slowdown distance since smooth acceleration and deceleration are desirable.

OB: Doctor Strangelove (0)

Anonymous Coward | about 2 years ago | (#42156369)

It's all about Purity [xkcd.com] of essence!

Re:Mathematician? (-1, Troll)

KrazyDave (2559307) | about 2 years ago | (#42156377)

I suspect there's a lot of artificial, unearned and overly complimentary praise for her because she is a woman in a male-dominated field.

Re:Mathematician? (-1)

Anonymous Coward | about 2 years ago | (#42156401)

She must get "the shaft" a lot (and I don't mean elevator shaft).

Re:Mathematician? (0)

Anonymous Coward | about a year ago | (#42156631)

Nah, that never happens.

Re:Mathematician? (0)

PPH (736903) | about a year ago | (#42156841)

Damn! Now I have this image [beloblog.com] stuck in my head.

Re:Mathematician? (5, Interesting)

Samantha Wright (1324923) | about 2 years ago | (#42156397)

A professor once described to me an elevator system at his former place of employment that used machine learning to try and anticipate where the elevator should be when not in use. At the start of the day, for example, the elevators should rest on the ground floor, so that they can collect people going up; similarly, toward the end of the day, they should rest at the top, since the overwhelming majority of people would be going down.

In a real-world setting you may have other phenomena that actually need to be learned, such as different groups taking lunches at set times of day, large meetings that cause several floors to congregate on one, et cetera. This problem can be considered from several different angles within ML; either as a regression problem or classification, for example.

Speed also needs to be optimized not just based upon the desire to reach the destination quickly, but also considering the rate at which the mechanisms will wear out, the energy consumption caused by more rapid movement, and to encourage people to use the stairs.

Given the potential complexity of how many parameters and models can potentially be considered... yeah, you want someone with a serious background in applied optimization, statistics, or artificial intelligence.

Re:Mathematician? (-1)

Anonymous Coward | about a year ago | (#42156499)

Elevator algorithms were pretty standard CS curriculum back when I was in college in the early 90's. This smells like another "Let's make women feel like they matter in technology by making a big deal out of something any halfway decent grad student can already do" type story.

Re:Mathematician? (1, Insightful)

vurian (645456) | about a year ago | (#42156551)

While you smell like someone who's had an abstract exercise in his first year and now knows everything about the problem area, just because you've never been hired to solve any real problems.

Re:Mathematician? (1)

Anonymous Coward | about a year ago | (#42156637)

Elevator algorithms were pretty standard CS curriculum back when I was in college in the early 90's. This smells like another "Let's make women feel like they matter in technology by making a big deal out of something any halfway decent grad student can already do" type story.

Man I was with you until the second line. There's some latent woman-hate going on. What's the problem bro? Women turning you down too fast?

Re:Mathematician? (1)

Anonymous Coward | about 2 years ago | (#42157937)

Women turning you down too fast?

They've optimized that, too.

Re:Mathematician? (-1)

Anonymous Coward | about a year ago | (#42156963)

Lol. You smell like a misogynist to me, and one whose early-90s CS curriculum didn't actually cover the NP-hard nature of human-driven unpredictable real-world elevator usage patterns in multiple-elevator high rise office buildings at that. Convince me otherwise with even the faintest beginnings of how you would go about finding the actual (as opposed to theoretical) optimal solution to a 6-elevator 50 story 250-people-per-story 3-standard-workshift instance. Good luck.

Re:Mathematician? (0)

Anonymous Coward | about 2 years ago | (#42158081)

Barbara/tomhudson: Your work @ siemens & the "fine" SCADA controller code you did there doesn't qualify you to speak here.

Re:Mathematician? (1)

waveclaw (43274) | about a year ago | (#42156985)

A professor once described to me an elevator system at his former place of employment that used machine learning to try and anticipate where the elevator should be when not in use.

I wonder how a machine learning program deals with the 10 year old who thinks it is funny to press every single floor button then get off on a random stop. Usually when at least half the building's population is running 5 minutes late for their flight.

Re:Mathematician? (1)

Anonymous Coward | about a year ago | (#42157149)

Check weight at each stop and compare. If there's no change for 2-3 stops, reset all stops made from inside the elevator (but keep those made externally).

That's just something I thought of right now and it has obviously not been tested in practice. There might be problems with it.

Re:Mathematician? (3, Insightful)

samkass (174571) | about a year ago | (#42156989)

One fairly new building in south Manhattan has a system where you type the number you want to go to before entering the elevator waiting area, and it tells you what door to wait in front of. When the elevator arrives it lists the floors it will stop at. It seems to optimize for minimal elevator usage, minimal wait times, no overcrowding, etc. Once the elevator system has a little more information it can do a lot better.

Re:Mathematician? (2)

DiSKiLLeR (17651) | about a year ago | (#42157417)

That is pretty standard, we have those in New Zealand which is a pissy tiny little country.

Re:Mathematician? (0)

Anonymous Coward | about 2 years ago | (#42156425)

There is probably a trade-off of lift capacity vs. velocity. i.e. Given the same means of propulsion, (put crudely) you can lift fewer people fat higher velocity or more people at a slower velocity.

The "faster" the building owners are interested in is probably the number of passengers per unit of time that can make it to the observation deck, not the duration of any one single trip of the elevator car.

I am neither an engineer nor a mathematician!

Re:Mathematician? (0)

Anonymous Coward | about 2 years ago | (#42156445)

Not sure if you were really trying to say that this job was for a man instead of a woman....

Re:Mathematician? (1)

Florian Weimer (88405) | about a year ago | (#42156531)

Isn't making the elevator go faster a job for an engineer? Does one really need to be a mathematician to know that a faster elevator moves people faster?

If the elevator can make stops along the way, it probably refers to mean travel time, and it's an entirely different problem.

That being said, the "surfboard feature" is really, really, old. A lot of elevators have on-demand overrides which prevent intermediate stops. So the article might just be an infomercial for the elevator company after all.

Re:Mathematician? (0)

Anonymous Coward | about a year ago | (#42156621)

My guess is that the elevator was using a general purpose algorithm before she changed it. If you know that the elevator is an express to the observation deck, you can accelerate to maximum speed without putting too much stress on it or wasting too much energy.

Re:Mathematician? (0)

Anonymous Coward | about a year ago | (#42156839)

I hope a mechanical engineer took into account the additional stress onto the elevator's cables, pulleys, guide rails and brake systems that a 20% increase in speed will cause... if this woman alone threw a number without taking into consideration the factors mentioned above, GOD help those tourists when one of those boxes fail.

Re:Mathematician? (4, Insightful)

Idarubicin (579475) | about a year ago | (#42157007)

Isn't making the elevator go faster a job for an engineer? Does one really need to be a mathematician to know that a faster elevator moves people faster?

I suspect that the problem here is a failure on the part of the article writer. The author was probably just looking for any sort of answer to 'What's the most famous building you've ever done any work for?', rather than 'what's the most mathematically-interesting part of your job?'

It's also possible that there's a little bit of complexity being glossed over here. For the Empire State Building, visitors take up to three consecutive elevator rides to get to the observation decks: one to get up to the 80th floor, another from 80 to 86 and the main observation deck (though the hearty can take the stairs), and an optional, extra-charge trip from 86 up to the topmost observation area on 102. Visitors form queues for tickets, security, and each elevator ride (both up and down).

While speeding up any of the elevators might seem like a good thing, it runs the risk of causing crowding and bunching of passengers waiting for the now-overloaded next stage. Making one set of elevators faster could increase wear and tear on those elevators (and increase both energy use and passenger discomfort) without improving overall throughput; I can see how there might be some serious mathematical optimization going on there. As well, it's possible that our mathematician was involved in optimizing all of the building's elevator speeds and timings, and not just the elevators dedicated to observation deck service: a much more difficult optimization problem.

This job has... (-1)

Anonymous Coward | about 2 years ago | (#42156341)

its UPS and DOWNS.

Yuo f4il it (-1)

Anonymous Coward | about 2 years ago | (#42156431)

but suufice it BSD has 4lways There's no real problems For it. I don't USERS OF NETBSD took precedence

Cool day job? (-1, Redundant)

RedHackTea (2779623) | about a year ago | (#42156505)

Eh, it has its ups and downs.

/obligatory cliché joke

Never never never... (2)

Ossifer (703813) | about a year ago | (#42156529)

... say "I feel like I get paid to play videogames." That basically says "please cut my salary by $30,000.00"...

Future algorithm ... (4, Funny)

fahrbot-bot (874524) | about a year ago | (#42156563)

... when elevators can move in more than one plane: 10 PRINT CHR$ (205.5 + RND (1)); : GOTO 10

Future fortune ... (1)

Anonymous Coward | about a year ago | (#42157273)

An ELEVATOR PROGRAM written without the use of a LOOP, VARIABLES, and without very complicated SYNTAX.

What? (0)

Anonymous Coward | about a year ago | (#42156661)

If she was optimizing and worth anything trying different initial conditions would be the smallest part of the whole operation. Developing the math models for the system and tightening the ranges that approximations are used over would the large part of the operation. I have no idea why it would seem like a video game unless the output is horribly verbose. I suspect the individual cherry picked to show the most fun parts of her work and not the soul sucking bureaucracy around it.

Improve the score!? (1)

loufoque (1400831) | about a year ago | (#42156697)

What do you mean improve the score?
You mean the programmers aren't even capable of solving the problem of finding the best solution?

Even if it's NP-complete, it's not like there are so many elevators that you can't find the best solution in reasonable time.

Re:Improve the score!? (0)

Anonymous Coward | about a year ago | (#42157179)

Then do it.

Re:Improve the score!? (1)

loufoque (1400831) | about 2 years ago | (#42158095)

Sure, I'm a consultant. You can hire me for the right price, no problem.

Harddisk access algorithms (1, Interesting)

udachny (2454394) | about a year ago | (#42156903)

There are so many different algorithms for hard disk seek, read and write functions that I think it would be a complete waste not to look at them when creating an elevator algorithm. Look it up, I think it's all there.

Good point - However... (0)

Anonymous Coward | about 2 years ago | (#42158115)

Already covered here -> http://hardware.slashdot.org/comments.pl?sid=3287917&cid=42156255 [slashdot.org] .

* In fact? I'd say the REVERSE of that which you have... how so??

I'd say the hard disk people used elevator folks' ideas though, especially considering the name of the algorithm employed.

APK

P.S.=> See the link, you'll understand...

... apk

and her iPOD has (3, Funny)

cellocgw (617879) | about a year ago | (#42156905)

one certain Aerosmith song on it.

in the old days (0)

Anonymous Coward | about a year ago | (#42156921)

code was tested in N Y City, on the grounds that new yorkers are more impatient, so if they were happy.....

Otis? Hmmm... (2)

jimicus (737525) | about a year ago | (#42157001)

Rumour has it that Otis have (or at least had) a UK office in the town of Reading (for our American cousins, the town is pronounced "Redding").

Their receptionist answered the phone with "Hello, Otis Reading?"

Re:Otis? Hmmm... (0)

Anonymous Coward | about a year ago | (#42157465)

Siemens used to have an office in the UK town of Staines (yes, really! though it's no longer there) You can imagine how the receptionists answered the phones, "Hello, Siemens Staines"

Most needed optimization (2)

Richy_T (111409) | about a year ago | (#42157025)

Multiple forced door closings when people hold the door open to chat.

Second most needed optimization:

Give me an ETA so I know when I'd be better off taking the stairs.

Most annoying feature that needs to be removed (some elevators):

If you'd manually hold the door for someone (those door open buttons are hard to find in a hurry sometimes. I believe there's even a paper on it), the door would then close v_e_r_y s_l_o_w_l_y while beeping reproachfully at you. The last thing I need first thing in the morning is passive-aggressiveness from a machine.

It's called nudging in the trade... (2)

the_rajah (749499) | about a year ago | (#42157291)

You will most commonly find it in large urban areas like NY and Chicago. In the Midwest where I worked in the elevator business, it's rarely a requested feature because folks aren't in such a rush in general.

So why are elevators still so dumb? (1)

Anonymous Coward | about a year ago | (#42157085)

They have a built-in weight sensor, how come they don't know when they're full? At rush hour, elevators are always full and they still stop on every fucking floor because especially at rush hour, there are always people waiting outside. And of course nobody can get in and nobody wants to get out. That's hardly an optimization conundrum, it's sheer stupidity.

In the article she says the main goal is to minimize waiting time. But isn't the time you spend in the elevator also waiting time, and isn't that much less comfortable than waiting outside? So the primary goal should be to minimize the length of a ride, not to minimize pre-boarding waiting time. If the waiting time before the elevator arrives exceeds 20 seconds or (more realistically) 5 minutes and you're not disabled, you can still choose to take the stairs, which means you're doing something for your health and the others have a faster ride, win-win.

Re:So why are elevators still so dumb? (1)

BradleyUffner (103496) | about a year ago | (#42157203)

They have a built-in weight sensor, how come they don't know when they're full? At rush hour, elevators are always full and they still stop on every fucking floor because especially at rush hour, there are always people waiting outside. And of course nobody can get in and nobody wants to get out. That's hardly an optimization conundrum, it's sheer stupidity.

Just because the volume of the elevator is physically full of people doesn't mean that it's at it's maximum weight. Not every person weighs the same and takes up the same amount of floor space.

Not all elevators have load weighting.. (1)

the_rajah (749499) | about a year ago | (#42157561)

Those that do, are usually set at around 75% of rated capacity. When load weighting is activated, the car should ignore hall calls, but, obviously, cannot ignore car calls.

Yes but.... (4, Funny)

guruevi (827432) | about a year ago | (#42157433)

Does it also simulate who farted?

I don't think (1)

DiSKiLLeR (17651) | about a year ago | (#42157435)

I don't think there's any intelligent code running the elevators in my building.

I live in a 14 floor apartment building. I frequently come home in the evenings to see both elevators just chilling idle on the 14th floor....

It makes me want tear my hair out.

The elevators in the high rises I work in don't seem to have these problems. The building I specificlaly work in most of the time has 6 elevators though so its less of an issue though.

There are still a lot of relay controllers in use. (1)

the_rajah (749499) | about a year ago | (#42157591)

Yes, pre-microprocessor, relay logic elevator controllers. I see lots of them that were put in 40+ years ago still working and doing their job after all these years.

Single click lift (0)

Anonymous Coward | about a year ago | (#42157559)

In a busy building the best way to improve elevator capacity is to make people select the destination level before boarding. So instead of saying I want to use the lift I'll tell you where to later, the control system can optimise movements a lot better

Pressing both the down and up buttons (1)

Grieviant (1598761) | about a year ago | (#42157603)

I'd like to hear her comments on people that press the up and down buttons when they simply want to go down. It irritates the hell out of me because I believe this practice increases the average travel time for people already on the elevator as well as the impatient double-button-pusher himself.

For example, say someone on floor 6 (who wants to go to the ground floor) presses both buttons and then gets on while the elevator is on its way up. The extra delay caused by the unnecessary stop at floor 6 means, statistically speaking, that people on floors 7 and up will have more time to summon the elevator before it reaches its highest floor and eventually descends to floor 6 again on its way to the bottom.

When the double-button-pusher issues their goofy "Oh, I'll just get on for the ride ... " comment, I frown menacingly and stare at them for the duration of the trip.

"to do the greatest good for the most people" (0)

circletimessquare (444983) | about 2 years ago | (#42157819)

socialist scum

this otis elevator sounds like a communist company. whoever this otis was, he obviously was no real capitalist or real murican

a real murican elevator would have a real murican algorithm, and not an algorithm by this eurotrash muslim atheist Theresa Christy. a "mathematician?" obviously some liberal college major where they teach her women should be allowed out of the home

the real murican elevator algorithm would scan everyone's wallets, and only one guy, the guy with the greatest amount of cash in his pocket, would get to use all of the elevators for him personally, 99% of the time, even if he wasn't using the elevators and everyone else had to use the stairs

Happy Vertical People Transporter (0)

Anonymous Coward | about 2 years ago | (#42158193)

99 comments so far and no mentioning of the predicting Happy Vertical People Transporters in The Hitchhikers' Guide to the Galaxy?

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