Domain: unc.edu
Stories and comments across the archive that link to unc.edu.
Comments · 912
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Re:Legal under Jenkins Act of 1949
According to this article, the Federal Government disagrees about immunity for Indian tribes under the Jenkins act. They assert that theh Jenkins act would apply for shipments FROM indian reservations to non-indians, just not TO indian reservations. This does not appear to be legally clear, and I find this assertion confusing. I don't see how the federal government can make indian tribes report tax information since they are on sovereign land, unless there is a treaty or something?
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Interesting Haptic ApplicationsMany interesting haptic applications I have come across were not mentioned in the article. SensAble's Phantom devices are being used for simulations like painting, sticking needles in people, and feeling up a cow's rear. Some games have also been developed for or integrated with the Phantom, such as Haptic Battle Pong (previously discussed on Slashdot), Haptic BlockTower, Haptic Dueling Game, and Haptic Quake (my own creation).
I expect we can also look forward to seeing many great new haptic applications being created as a result of SensAble contest that the article mentions. Being able to feel and interact with simulated objects in a very intuitive way will undoubtedly become an increasingly import part of how we use computers.
I would personally appreciate hearing from anyone out there who has an interesting haptic application in the works (or wants to hear about mine). scottgilroy2000 - a - yahoo dot com
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Re:iPod = Messenger Bag = Pro SUV
Humvees old school?!?!?
JEEPS are OLD SCHOOL!
We actually use our 95 Jeep Cherokee the way it was meant to be used: climbing 3 ft high rocks and dropping down 60-degree slopes into muddy ravines.
The only thing a Humvee is good for is towing practice for Jeeps!
Sorry for going a leeetle off-topic, but I HAD to defend the good old Jeep! -
Re:Linus looks like a penguin
Man, you're on crack.
That's the skinniest penguin I've ever seen! -
UNC Research
UNC has an article about a similar project.
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Also BATS
Another similar project is BATS here at UNC-Chapel Hill.
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Re:Correct me if I'm wrong...
Taken from a 1999 page, good idea.
Laura's always been the go to gal on this one...
WHEN U.S. WORKS PASS INTO THE PUBLIC DOMAIN
anon cause i think i've whored this link b4.. -
Right now, baby!
Ooh, sexay sexay! (Not.)
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Re:So that's why my watch is running slow.
No, that's how it used to be.
As far as I know that's how they still are: days and years are astronomically defined. But I am no expert, I don't know what the official answer is. According to this site, the 86,400 SI seconds per day is literally true for January 1, 1900, but not necessarily true for any other day.
If a day was defined as a true astronomical measurement we would have no need for leap years.
The astronomical definition of a day and year is precisly why we have a need for leap years. The rotation of the earth doesn't precisely match the revolution of the earth, so we need leap years to make sure that the year doesn't drift around the seasons slowly and steadily.
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Re:So that's why my watch is running slow.
No, that's how it used to be.
As far as I know that's how they still are: days and years are astronomically defined. But I am no expert, I don't know what the official answer is. According to this site, the 86,400 SI seconds per day is literally true for January 1, 1900, but not necessarily true for any other day.
If a day was defined as a true astronomical measurement we would have no need for leap years.
The astronomical definition of a day and year is precisly why we have a need for leap years. The rotation of the earth doesn't precisely match the revolution of the earth, so we need leap years to make sure that the year doesn't drift around the seasons slowly and steadily.
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Re:Energy release
According to my geology textbook,
The amount of energy released in a 9.0 magnitude earthquake is:
20,000,000,000,000,000,000 ergs
In contrast, the annual US energy consumption is:
630,000,000,000,000,000,000 ergs -
Re:Philosophy, semantics, yadda yadda
It's probably important to distinguish between the two things you've mentioned, "think" versus "act intelligently". In AI, what we usually call "thinking" is an algorithm which given a set of data (usually in a "toy world") can perceive data, act upon the world, receive feedback and alter its plan accordingly. More accurately this would be "machine learning" rather than "thinking", a word which definitely has philosophical entertwinings which may not be useful questions (as Dijkstra points out).
Yes, machines can carry out intelligent behavior, but not necessarily because they were programmed to perform an explicit set of actions. Think of genetic algorithms and evolution: You specify your RVs, chances for mutations, etc and a way for the computer algorithm to measure the success of each individual in the population (or a way to manually select your favorites) and you create an algorithm to 'evolve' a particular type of solution. One interesting one is the animated Luxo lamp which "hops" (think Pixar studios animation). We can call this intelligent behavior to be sure, but we didn't program the machine to reach a specific goal; we just told it how to measure success. It's simply getting the ball rolling, and then watching what the machine might produce. Very fascinating stuff if you get a chance to see a video clip of this hopping Luxo lamp and the explanation.
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Graphic Card Technology
PCI-E has symmetric bandwidth. Current generation graphics cards will undoubtedly not be able to take advantage of this feature, they've spent so long getting data to the graphics card that thats all they're optimized for, but in the long run this has some crucial implications.
Namely, it allows for graphics cards to operate better in situations exactly like this; clustered applications. As it stands, the graphics card can crunch an enormous amount of data, but is extremely poor at sending it back to the CPU & system. It's optimized for screen dumping only.
Sony's Cell is going to be absolutely crucial as a tech demo for this foresighted technology. We're heading towards a more distributed computer architecture where various specialized units pipe data between each other.
In summation,
Its my hope that eventually graphics cards will catch up and perform better bi-directionally. After that, we've got to wait another 5 years for PCI-E implementations to catch up and perform better switching (vis-a-vise multiple fully-switched x16 busses). We are moving away from the CPU for high performance computing; the cpu currently performs both control and data-processing. Graphics cards are just the first wave of the distributed architecture phenomena, Cell will be a light-year jump towards the future of computing in the intricate levels of hardware reconfigurability. there's a good powerpoint on the patents behind cell here.
Ultimately this will lead towards the tearing down of the computer as a monolithic device, and a rethinking of what exactly the network and os's roles are. Queue exo-kernel and DragonFly BSD debates. -
The Ghost of Usenet Postings Past
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Re:What is it about Cathedrals?
"igb" is correct; in fact, some cathedrals have never been finished, even though they are quite useful and beautiful! Antonio Gaudi's La Sagrada Familia Cathedral in Barcelona is perhaps the perfect example of a fantastic structure that is taking centuries to construct!
Brooks has some interesting points on this in The Mythical Man Month:
A cathedral is typically being built by many architects of course. This is at least true by the fact that most of the architects did not live long enough to survive the completion of the building. Normally although the successor of an architect has shared or at least continued the construction along the ideas and visions of his former colleague.
But in Europe there are also cathedrals, that have been built by a series of architects where one did not share the ideas and vision of the previous one. These normally have a longer building time (things were destroyed and rebuilt or changed) or a very inconsistent look. But I do not think, ESR has enough history knowledge to know about this
;-).The term normally is of course important here, since there are cathedrals, that have different styles combined within them and are still very beautiful
Open-Source on the other hand generally tries to built a cathedral without an architect. Interestingly it works -- somehow, most of the time
;-). -
Wet hair rendered
I was amazed at the rendering of long, wet hair. I dug up this cool paper on the subject.
With every movie, computer graphics takes another step. Antz had water, Lion King had computer-generated herds... Although we're really close, we'll get to a point where the animation no longer constrains the story. -
Re:No, it won't
From the article you will see that research studied two particular groups of genes:
(1) Mitochondrial DNA - This DNA never recombines. The genes are passed *exclusively* down the maternal side of the family tree ie. daughters have near identical mitochondrial DNA to their mothers (plus or minus the odd genetic mutation, which allows the scientists to timestamp the changes).
(2) The Y Chromosome - This DNA never recombines. The genes are passed *exclusively* down the paternal side of the family tree. ie. sons have near identical Y-chromosomes to their fathers (plus or minu the odd genetic mutation, which allows the scientists to timestamp the changes).
The mutation rate of mitochondrial DNA is around 1 change in 33 generations, or around 520 years. That gives people quite a long time to move around and form new settlements. -
When U.S. Works Pass into the Public Domain
Gone With The Wind was published June 30, 1936
Works published between 1923 - 1963 can be protected for upto 67 years, therefore Gone With The Wind became public domain last year, July 1, 2003. These estate Nazis have no legal recourse and should look for a real job rather than trying to police the internet.
Quick and easy copyright lifetimes:
http://www.unc.edu/~unclng/public-d.htm -
Re:good, we don't need that crap.
The same connectivity you love at home is now available in your car. In many vehicles nowadays, you can check your e-mail, view Web sites, even watch television, from the comfort of your driver's seat
Now that I've slurped back my "geek drool" and thought better of it, the idea of that sweet gadgetry massaging my technolust while I'm careening down the highway... is of course not only bad, but dangerous.
Each year, an estimated 284,000 distracted drivers are involved in serious crashes. Probably good to keep that number at least stable--if not lower--than it currently is. -
Re:Weapons...
Actually I was referring to extremists of all sorts, be they radical islamic mullahs or any other religious fundamentalist. Try reading this or this or even this.
Besides, isn't the battle on the plains of Armageddon from the Book of Revelations, not from the Koran? That should have been a bit of a hint right there. -
Re:If you liked...
They apparently did the same thing with the Tandy Color Computer for a while, during the early days of the 32K upgrade. Or at least so the rumour went.
Not for very long, though; soon enough 64K chips were cheap enough that nobody bothered selling the half-bad ones.
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REFERENCE
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Had a similar problem...
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what you kind of want is GLUI....
see Gui toolkits
GLUI would be a good one GLUI website
try it out
regards
John Jones
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http://www.johnjones.me.uk/ -
Re:Uhhh that's pretty obvious
Two words. Cultural Hegemony.
http://www.unc.edu/courses/2000fall/jomc245-001/cu ltural_hegemony.html -
Something GoodAfter reading this post, I went on the Google to check for some reasons on why to get a CS PhD. I came across a really nice article you might like called A Graduate School Survival Guide.
It's by a guy who got his doctorate and he discusses reasons to do so or not to do so. Hope it helps!
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Gary BishopGet in touch with Gary Bishop. He's a professor at UNC who has been working on maps and user interfaces for the blind. I believe he's got working software that you can download and is always looking for people to work with and help.
-m -
Other projects
Some of the other projects developed by students in the Enabling Technologies class at UNC might also interest you. Many of them are aimed at kids who have nothing to do in computer classes while their sighted peers get to use all the latest and greatest multimedia software. The assistive tech research group's home page also has some projects listed.
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Other projects
Some of the other projects developed by students in the Enabling Technologies class at UNC might also interest you. Many of them are aimed at kids who have nothing to do in computer classes while their sighted peers get to use all the latest and greatest multimedia software. The assistive tech research group's home page also has some projects listed.
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BATS: Blind Audio Tactile Mapping System
Check out the BATS project from the assistive technology research group at UNC. It's an open source mapping program written in Python to make maps accessible to people with visual impairments using text-to-speech synthesis, audio icons, 3D sound, and tactile feedback all using cheap commodity hardware. More info is available on the BATS web page. The latest version of the software for Windows is also available for download.
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Re:Ever heard of BATS?
I suppose I'll elaborate a bit. BATS is a project that uses auditory clues and a pointing device (like a mouse) to let blind people explore maps. An example from this pdf says that you could have your cursor positioned with a large body of water just to the left, in which case the user would hear sounds of water and the name of the body coming from their left side (I suppose it requires stereo sound). It sounds pretty neat, and may be just what is needed for this kid. Not sure what the availability of maps for it is like, but you can download the software from the link I provided above. It's funny that this came up, because I had just heard some co-workers talking about BATS the other day (one of them had worked on it apparently). Anyway, hope this helps.
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Ever heard of BATS?
This might be of interest to you. Not sure how visually impaired the kid is, but this is for those with no sight at all. BATS
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Re:Electoral voting helps prevent local heroes...
The high-population areas do indeed have more power than the small areas -- but they have slightly less power per unit person, which is how it should be.
No they don't. The math to prove that they don't is much to complicated to post, but you can go read it. However, that much math is above most people's heads, so we can go on pretending that rural states have a small benefit. (Also, that benefit is solely from "Effect 1", below)
they have slightly less power per unit person, which is how it should be.
Do you have any support for that reasoning? The rest of your post certainly doesn't. Everything else you write (regarding suppression of candidates who are only locally popular) is true- but would still be true even if Senators didn't count towards electoral votes.
To be more specific, the Electoral College has two separate effects, both arguably creating unfairness, and either capable of being removed without upsetting the other. Effect 1 is what you call the "clamping device", which causes states to assign all of their electoral votes to one candidate. Effect 2 is the fact that each state gets electoral votes equal to (population/400000)+2, instead of just (pop/400000).
Abolishing the Electoral College would remove both those effects at once, but reforming it could target just one or the other.
That makes it harder for those places to dominate the election.
Why yes, disenfranchising people does indeed make it hard for them to influence elections.
Consider a candidate who enjoys a 98% majority in San Frangiego and Boswash, but only obtains 35% of the vote in the rest of the country
As you know, that's a ludicrously unrealistic example. And yet, it doesn't even work... because even with a purely-popular vote, 98% of SF and BW is just 41 million people. Add in 35% of the rest of the country, and they still lose a popular election by 132 to 169.
(pretty dismal).
Dismal? It's only 12% less that the 47% approval that it takes to win a state today! -
Re:18-35 #1 ELECTION/VOTING REFORM:For the sake of discussion, I will ignore the fact that the current USA system actually increases the power of high-population areas, and instead use the simplifying interpretation that rural states get a small advantage.
Your vote won't count unless you live in the North East, Los Angeles, and a few other places
Wrong. Your vote would count just as much as anyone else's did- there just happen to be more people in those places.
Do you know why $10 from me buys just as much as $10 from Bill Gates?
And as a side effect the views of rural America won't be represented at all,
So you claim that rural people deserve more power than city people? Why is that? Does the country lifestyle make them inherently more moral?
Arguments like yours are terribly vulnerable to parody:
Your vote won't count unless you live in the North East, Los Angeles, and a few other places. And as a side effect the views of rural America won't be represented at all
- Your vote won't count unless you're a Christian, Muslim, Jew, or a few other religions. The views of Wiccan Americans won't be represented at all.
- Your vote won't count unless you're white, black, or maybe hispanic. The views of Asian-Americans won't be represented at all.
- Your vote won't count unless you're heterosexual, or maybe abstinent. The views of homosexual Americans won't be represented at all.
- Your vote won't count unless you're an moron, idiot, imbecile, or some other kind of retard. The views of intelligent Americans won't be represented at all.
See the pattern? You need to explain why one kind of minority deserves a boost to it's power, but not any of those others.
So if disenfranchising 40% or more of the population is your goal
Only 40%? The existing system has disenfranchised the 75% of voters who don't live in swing states, so that'll be an improvement.
Of course, according to your argument, 49% of the population is ALWAYS disenfranchised by the other 51%. From one point of view, that is true- but still meaningless. -
Re:18-35 #1 ELECTION/VOTING REFORM:
The electoral college helps protect smaller states from being dominated by larger states.
It did until the large states realized that they could gain electoral power by making all of their electors vote for the same candidate. Under the winner-take-all system, the Electoral College has a huge bias in favor of large states. The Banzhaf Power Index is about 3 times as high in California as in Montana. And that's ignoring the fact that all of the 3-vote states (and [especially] DC) are "decided", which gives the voters there even less influence.
In 2000, George W. Bush carried 30 states, though most of the most populous states did not favor him.
He carried 2 of the 4 most populous states. Otherwise, he wouldn't have had a chance.
True, the electoral college system is not perfect and perhaps should be replaced with a simple absolute majority
Direct popular vote, although a vast improvement over the EC, has problems of its own. Notably, the possiblity of a national recount. (If you thought Florida was bad...) For that reason, I think a better approach would be to constitutionally require every state to allocate its electoral votes proportionally like Colorado is considering.
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Re:This is clearly protected
It is outside of the copyright period in effect at the time of the film's initial release.
Um, I don't think so. I am not a lawyer, but if I read correctly, the original film (1977) might be in the public domain if published without notice (reference here and here) -- which seems extremely unlikely. And all the later movies would still be convered by copyright either way.A film seen by so many people becomes public domain as a result of having entered the cultural consciousness.
That sounds great in theory, but has a court ever actually said this?I say, ignore the Lucas 'warning', and hold your event.
This sounds like legal advice. Are you ready to accept financial responsiblity for their costs if your advice turns out to be unsound?Personally, I think they need to contact a lawyer rather than `Ask Slashdot'.
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Re:CRTs DO do 10 bit colour!
Others actually have internal 10 bit ramdacs but don't allow driver access to them. Such a pity.
The matrox parhelia is such a beast.... I mean matrox does provide gigacolor as either standalone or as a plugin for a limited number of applications, but maybe an easier way to play with that resolution is through full-screen opengl where 32 bit pixels can be used as 10+10+10+2 bit alpha.I'm thinking wrapping glui in python, but haven't got round doing that yet. Don't other cards also provide 10 bit resolution through opengl? might be worth a look. That's why I thought doing some opengl mojo is still way more compatible than using proprietary plugins.
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Re:Why don't they just describe the capacity inWell, we don't say "6 gigatimes more," so instead of saying "one exillion" we'll say "one sagan."
That sounds so cool. Unfortunately, there is a problem with it.
1 Sagan = 1 quintillion (US) = 1 trillion (EU) = 1 hexillion (Greek)
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GovStat Project at UNC and UMD
this project aims to bring visualization and understanding to the masses through the statistics coming from the US government.
http://www.ils.unc.edu/govstat/ -
Re:Price range of $200 to $800...
GPU is well suited for database operation:
Fast Database Operations using Graphics Processors:
http://gamma.cs.unc.edu/DB/
Hardware-based approaches to accelerate CPU intensive operations that arise in the context of non-standard database applications:
http://www.cs.ucsb.edu/~nagender/graphics.htm -
Re:More rationalizations for being cheap
This is an interesting example, but I wonder how your guy knows that file sharing is what is hurting his business. The music industry has complained that P2P has ruined their business but their numbers are going up? I think the recent downturn in music sales might have more to do with the recent dearth of quality pop music. That is just an opinion but so is your friend's opinion that P2P is what is hurting him. And my opinion is also the result found by a harvard study.Any good debater would know that you must back up your opinion with evidence rather than assertion. Does your friend have any evidance directly conecting his drop in business to filesharing?
As a former High School and College debater I am well aware of the usefulness of the type of briefs your friend produces and I recognize that the market is very small. However, I am also well aware that the problems your friend faces existed well before P2P came on the scene. High School and college debate are relatively small communities. These people see each other every weekend and they probably go to camp together over the summer. One of the main activities at summer camps is photo copping useful information. That is the primary motivation for going to camp. We would make sure someone went to camp every summer from our HS team just to be sure we had a copy of all the latest briefs? Did we pay for them? Well the camps are not cheap, but I suppose not. On the other hand no one would go to camp if they didn't come back with two or three decent cases. So maybe it is the camps stealing from your friend rather than the individual debaters (some camps do work very hard to prevent the reproduction of copywriter works but it is very hard to do when you have kids up all night and day at the photocopier).
In short, the photocopier, the word wide web, and plain old sharing (not file sharing) are, in my experience, a greater threat to your friend's livelihood. And I know it to be a fact. Your friend chooses to blame P2P but how does he know? -
Are CD Sales Really Down? Is P2P the Cause?There are conflicting reports about whether or not CD sales are down, and if so, whether file sharing is a causal factor. RIAA may well be fudging both so as to fake damages.
Here's a report that says "Nielsen Rating System At Odds With RIAA's Claim Of Lost Sales".
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Re:what part of "needs further study" dont' you geBut don't worry, even if a study or three come out demonstrating a link between non-ionizing radiation and cancer risk, the EPA will sweep it under the rug when Infinity Broadcasting supresses the evidence under the Bush Administration's Data Quality Act.
Actually, a study or three demonstrating a statistically significant link between nonionizing radiation and cancer is exactly what I would expect, even in the absence of real harmful effects.
This is epidemiology--hardcore statistics. When determining the risk associated with some factor, you can never be entirely certain that the effects you see are 'real', and not just due to random clustering. Toss a coin ten times--you'd expect to get heads five or so times, but occasionally (1 time in about a thousand) you'll see ten heads in a row.
By making (generally reasonable) assumptions about the nature of the randomness in the data, scientists and epidemiologists tend to come up with one or more measures of how likely an apparent result is to be genuinely significant. Generally, a result is taken to be 'real' if there is less than a 5% chance that the result is the result of noise (a P value of less than 0.05). Alternately, a study may state an odds ratio and 95% confidence interval ("If you take drug foostatin you are 1.7 times more likely to have symptom bar (95% CI 1.4 to 1.95)") denoting that the relative risk is 95% likely to fall in the stated interval.
Under those circumstances, if the scientists do everything correctly, and account for every possible confounding factor, and do all their math correctly...that still leaves as many as one study in every twenty potentially reaching the incorrect conclusion.
The journal in question here--The International Archives of Occupational and Environmental Health--isn't exactly a top-flight journal, either. I'm not at work at the moment so I can't check their archives, but their impact factor is fairly low. (Down to 0.924 in 2002, declining steadily since 1997.) Yes, impact factor is by no means the only criterion by which a journal should be judged--but Nature they are not. Unfortunately, the Wired article refers to an 'upcoming' paper, so I can't get at the publication cited.
Looking at the other paper mentioned in the Wired article demonstrates that Wired can't be trusted to accurately report the findings of scientific papers, either. Wired says:
Two years ago an Italian study found death rates from leukemia increased dramatically for residents living within two miles of Vatican Radio's powerful array of transmitters in Rome.
The abstract of the original paper in the American Journal of Epidemiology says: (in part, emphasis added)
...In the 10-km area around the station, with 49,656 residents (in 1991), leukemia mortality among adults (aged >14 years; 40 cases) in 1987-1998 and childhood leukemia incidence (eight cases) in 1987-1999 were evaluated. The risk of childhood leukemia was higher than expected for the distance up to 6 km from the radio station (standardized incidence rate = 2.2, 95% confidence interval: 1.0, 4.1), and there was a significant decline in risk with increasing distance both for male mortality (p = 0.03) and for childhood leukemia (p = 0.036). The study has limitations because of the small number of cases and the lack of exposure data. Although the study adds evidence of an excess of leukemia in a population living near high-power radio transmitters, no causal implication can be drawn. There is still insufficient scientific knowledge, and new epidemiologic studies are needed to c
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2d treadmills, motion sickness and RedirectionThis is reply to several posts. There's been a couple inquiring about other kinds of 2-d treadmills and spheres, both of which exist (see below for links to videos and papers).
There are fundamental problems with all of these types of devices-- they 1) don't let the body handle momentum naturally and 2) don't stimulate the vestibular system in a way that is consistent with the visual or proprioceptive (the body's sense of where its limbs are) cues.
1) Momentum: On a 2-D treadmill, the omni-directional treadmill is supposedly fast enough that it allows for running. But when you are running and then change direction quickly, your body will lean into the turn to counter its momentum. Doing this on the treadmill will make you fall over. Someone once described it as "running on a slippery ice cube".
2) Vestibular cues: Our body can sense motion even without visuals or body movements. This is why some flight simulators have motion platforms [://www.simlabs.arc.nasa.gov/vms/motionb.html]. One post above said that the treadmill should reduce motion sickness because it provides body motions as well as visuals. But a treadmill doesn't cue the vestibular system. One theory of motion sickness is that it results from a mismatch of visual and vestibular cues. In the back seat of a car, your visual cues say you are still (relative to the inside of the car) but the vestibular system says you are moving. Similarly in a IMAX theater or while playing an FPS on a big screen, your visuals say you are moving but your vestibular system says you are still. Knowing how you are moving is critical for maintain balance and even surviving. The mismatch in visual and vestibular cues interferes with your ability to balance, and that's why dizziness results.
Luckily, one can fool the vestibular system, much as we can fool the visual system. Techniques include "wash-out" on motion platforms, electrical stimulation, and Redirection. Wash-out is where the motion platform moves the user to simulate the virtual motion, but then sneaks her back to the center of the room at an acceleration that is below what her vestibular system can detect. The shifting tiles look like a fabulous idea, and I wonder if one could implement a form of wash-out on those tiles.
Links
- Nasa Ames VMS motion simulator
- http://www.simlabs.arc.nasa.gov/vms/motionb.html
Sphere http://www.vr-systems.ndtilda.co.uk/sphere1.htm2-D treadmills
Omni directional treadmill http://www.movesinstitute.org/darken/publications/ ODT-UIST97.pdf
Torus treadmill (great video) http://intron.kz.tsukuba.ac.jp/vrlab_web/torustrea dmill/torustreadmill_e.html
Redirection http://www.cs.unc.edu/~eve/rdw/
One more thing, the problem with, as one post suggested, implementing VR in a huge wide open space (like a desert) is tracking. The computer needs to know where your head is and in which direction you are looking, very accurately and quickly, so it can draw the virtual scene from your perspective. By accurately, I mean with millimeter precision, and by quickly I mean it must update the images within tens of milliseconds of your head moving. If you focus your eyes on your figure at arms length, then rotate your head right and left, the reflex that moves your eyes to keep them locked on your finger is called the VOR (vestibular ocular reflex). It can react to head movements in 10 milliseconds.
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2d treadmills, motion sickness and RedirectionThis is reply to several posts. There's been a couple inquiring about other kinds of 2-d treadmills and spheres, both of which exist (see below for links to videos and papers).
There are fundamental problems with all of these types of devices-- they 1) don't let the body handle momentum naturally and 2) don't stimulate the vestibular system in a way that is consistent with the visual or proprioceptive (the body's sense of where its limbs are) cues.
1) Momentum: On a 2-D treadmill, the omni-directional treadmill is supposedly fast enough that it allows for running. But when you are running and then change direction quickly, your body will lean into the turn to counter its momentum. Doing this on the treadmill will make you fall over. Someone once described it as "running on a slippery ice cube".
2) Vestibular cues: Our body can sense motion even without visuals or body movements. This is why some flight simulators have motion platforms [://www.simlabs.arc.nasa.gov/vms/motionb.html]. One post above said that the treadmill should reduce motion sickness because it provides body motions as well as visuals. But a treadmill doesn't cue the vestibular system. One theory of motion sickness is that it results from a mismatch of visual and vestibular cues. In the back seat of a car, your visual cues say you are still (relative to the inside of the car) but the vestibular system says you are moving. Similarly in a IMAX theater or while playing an FPS on a big screen, your visuals say you are moving but your vestibular system says you are still. Knowing how you are moving is critical for maintain balance and even surviving. The mismatch in visual and vestibular cues interferes with your ability to balance, and that's why dizziness results.
Luckily, one can fool the vestibular system, much as we can fool the visual system. Techniques include "wash-out" on motion platforms, electrical stimulation, and Redirection. Wash-out is where the motion platform moves the user to simulate the virtual motion, but then sneaks her back to the center of the room at an acceleration that is below what her vestibular system can detect. The shifting tiles look like a fabulous idea, and I wonder if one could implement a form of wash-out on those tiles.
Links
- Nasa Ames VMS motion simulator
- http://www.simlabs.arc.nasa.gov/vms/motionb.html
Sphere http://www.vr-systems.ndtilda.co.uk/sphere1.htm2-D treadmills
Omni directional treadmill http://www.movesinstitute.org/darken/publications/ ODT-UIST97.pdf
Torus treadmill (great video) http://intron.kz.tsukuba.ac.jp/vrlab_web/torustrea dmill/torustreadmill_e.html
Redirection http://www.cs.unc.edu/~eve/rdw/
One more thing, the problem with, as one post suggested, implementing VR in a huge wide open space (like a desert) is tracking. The computer needs to know where your head is and in which direction you are looking, very accurately and quickly, so it can draw the virtual scene from your perspective. By accurately, I mean with millimeter precision, and by quickly I mean it must update the images within tens of milliseconds of your head moving. If you focus your eyes on your figure at arms length, then rotate your head right and left, the reflex that moves your eyes to keep them locked on your finger is called the VOR (vestibular ocular reflex). It can react to head movements in 10 milliseconds.
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Re:This sort of technology was shown last year....
Or a few years ago (2001?) at UNC Chapel Hill by Yang and Welch. See http://www.cs.unc.edu/Research/stc/publications/Y
a ng_CECG01.pdf -
Re:Kind of like this one here...
And UNC has PixelFlex, "a multi-projector display system that combines
multiple roughly aligned projectors into a unified high-resolution
display." -
Re:[OT] Why SI rules
In 1893, Congress adopted the metric standards, the official meter and kilogram bars supplied by BIPM, as the standards for all measurement in the U.S. This didn't mean that metric units had to be used, but since that time the customary units have been defined officially in terms of metric standards. Currently, the foot is legally defined to be exactly 0.3048 meter and the pound is legally defined to equal exactly 453.59237 grams.
That's from here.
I know you were joking, but I just had to point that out.
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Re:Doesn't this increase the danger?
Doesn't this increase the danger?
Well, possibly, but if someone is trying to communicate with you, it may be the best way anyway. Think about it. Would you rather they flash the lights, honk the horn or wave? You will spend more brain cycles trying to parse these messages. Generally, an interface that uses ingrained brain 'hardware' to communicate is usually better than teaching everyone that signal X means Y.
You may remember that we had that article on Facetop last week, where you can use your existing hand-eye coordination 'hardware' to drive the pointer. That sounds like really stellar UI. This is similar in that it would use humanlike social cues to communicate. (Then again... social cues? I must be new here.)
The only problem I'm seeing is that the facial expressions that a car can make are probably nothing like actual social cues, and that they would not be similar enough to trigger expression recognition code in your brain. Who knows. -
Re:Think Cigarettes company brand Crack...
All right, make me dig up the facts. Here the claim is 60mg of Nicotine is estimated to do the trick. And NIDA claims that a typical cigarette contains 10mg (or more). So, if those figures are correct, my statement should be revised to reflect that 6 cigarettes administered orally constitutes a lethal dose. I had read somewhere that 1 was sufficient, although I can't recall the source. I didn't pull that number out of my ass -- I pulled it out of someone else's ass
;) Thanks!