/me sticks out hand proudly. I have cable internet and cell service.
/joeyo, who has been landline free for a year and a half.
Re:No reading of minds yet
on
Going Cyberpunk
·
· Score: 2, Informative
A willing human could get a bundle of electrodes buried into his cortex, and plugged via a USB interface into your computer. Then, with a lot of practice against a program that gives visible feedback, the subject could learn to control the eletrodes enough to manuver a mouse or keyboard equivalent.
There are a number of technical problems that have yet to be solved. Firstly, there's biocompatibility. Any extracellular electrodes implanted in the brain get "walled off" by plaques remarkably quickly. And of course, as this happens the signals from the electrodes become weaker and weaker until they are useless
Secondly, there's the problem of spike sorting. There is, AFAIK, no fully automatic way to detect and sort spike trains from multiple-extracellular electrodes in real-time. (ie to be able to tell how many neurons are "talking" to any single electrode.)
Finally, the level of plasticity in the adult brain is an unknown quantity. Primate studies are suggestive, but there doesn't seem to be a consensus on how to best have a machine "talk" to the brain. Should we have the brain learn how to do it? Have the machine learn to do it? Some combination of these? What about for paralytics-- how do you train someone to use a very specific part of the brain. Remember that you're recording from at best a few hundred cells!
Any guesses as to how many of his existing muscular systems will be paralyzed by the tampering?
Probably surprisingly few if you have a good neurosurgeon. And if he is paralyzed to begin with it might not matter.
"The primary purpose of the DATA statement is to give names to constants; instead of referring to pi as 3.141592653589793 at every appearance, the variable PI can be given that value with a DATA statement and used instead of the longer form of the constant. This also simplifies modifying the program, should the value of pi change."
-- FORTRAN manual for Xerox computers
"No proper program contains an indication which as an operator-applied occurrence identifies an operator-defining occurrence which as an indication-applied occurrence identifies an indication-defining occurrence different from the one identified by the given indication as an indication-applied occurrence."
-- ALGOL 68 Report
"The '#pragma' command is specified in the ANSI standard to have an arbitrary implementation-defined effect. In the GNU C preprocessor, `#pragma' first attempts to run the game rogue; if that fails, it tries to run the game hack; if that fails, it tries to run GNU Emacs displaying the Tower of Hanoi; if that fails, it reports a fatal error. In any case, preprocessing does not continue."
--From an old GNU C Preprocessor document
Has anyone else run across citeseer yet? It's pretty freaking amazing. It is a google-esque directory of publications that are available online (html, ps, pdf, whatever.) It lists abstracts and citations (in Bibtex!) and all the information they have can be peer edited and corrected!
you could always run your own MTA. It's what I do... IMHO, if something is important to you, you need to take personal resposibility for it (you nimwit.)
Well, some fairly complex calculations are inevitable. After all, how exactly is the adaptation occuring?
The simplest way would be if the brain had some sort of look-up table: when I see the ball at position X1, I move to position Y1; when I see it at X2, I move to Y2. Or more generally: position Xn -> Yn. In this way you could build up a detailed model of your environment and the mechanics of your interaction with it. However, it can be shown that this is most likely is not the way it works. Why? Generalization.
Tasks and environments which are learned in one situation are generalizable to others. This can be shown with prism glasses, rotating rooms, micro-gravity, macro-gravity, etc. Basically, in any situation in which the physics of the universe or the physics of the subject, or the interaction between the two is changed, the subject can adapt in a robust way that a table-lookup can't touch. Reza Shadmehr has some very interesting results on this topic.
So how else could it work? Moving up a level in complexity we get to what is known as an internal model. The internal model describes the mechanics of the universe and the bodies interactions with the universe. When the mechanics changes (eg prisim glasses) the model is updated via proprioceptivie information. The difference between this and the look-up table above is that it is represented in such a way that extrapolations to new situations are possible. We can mathematically represent such an internal model as a jacobian matrix, very similar to those that you may remember from your mechanics classes.
This does beg an interesting question though: how the heck is our brain able to quickly invert matrices?;)
Another possibility is that the brain is actually "aware" at some level of the laws of physics and is doing calculus to figure out trajectories. This is also unlikely; there are simply too many degrees of freedom. Robot designers don't generate movement by solving laws of motion, they use feedback control.
(If you're familiar with control theory you might have been wondering about feedback control. Might not the brain be getting a real-time error signal and correcting its movement in the way that a robot would? It turns out that this is unlikely. Nerve conduction velocity is too slow so there is too much lag between the extremities and the CNS. If our motion were controled by feedback alone, smooth motion would be impossible. Clearly the proprioceptive error signal is there but it acts on a much slower timescale.)
Here are some photos from a pumpkin launching catapult that I made with some fellow physics students back in college. It's technically not a trebuchet because we didn't use a sling. The pumpkins kept getting tangled in it. Also including one greatly complicated the calculations.;)
Tbink of it this way: more shuttle launches == more money for the contractors, who, btw, are/guaranteed/ to make money on their contracts. Not much incentive to innovate there, eh?
Simple solution: make methane fuel on mars and cut your costs enormously.
CO2 + 4H2 -> CH4 + 2H2O
All you have to do is bring the hydrogen; the carbon dioxide is already there on Mars. And the reaction is exothermic, so you can do something useful with the waste energy too.
If you electrolyze the water you can produce more oxygen:
2H2O -> 2H2 + O2
Now for each unit of hydrogen that you bring to Mars, you get twelve units of methane/oxygen. And this is the simplest case, you can do better if you use some clever chemistry.
See Robert Zubrin's book, The Case for Mars for more information.
I don't know, I tend to agree with him-- this is NOT the path to neuralprosthetic devices. We won't know exactly what they are doing until the journal article comes out tomorrow, but it seems like they could just as effectively delivered a shock to the rats ass: left cheek to go left, right cheek to go right. There hasn't been any advance in the neuroscience.
Now if they could deliver signals directly that caused the limbs to move in a coordinated fashion... well, that is another story.
You get the stories, the best comments, and a plot of the new comments and percent signal plotted verus time. It's great. I only log into slashdot now when I post comments.
I saw a few with color-- at least one was bright green and there were a few that were green-yellow and some that appeared to be redish. I don't know how much of this was an afterglow artifact and how much of it was real, but it looked stunning.:)
My vantage point was Kerr Lake, NC. I went camping with some friends and we took a home-made dobsonian telescope to stargaze with prior to the shower. The conditions were about perfect. The sky was clear, there was very little light pollution, it was dry, windless, and actually pretty warm for mid-November.
I dont really know how to gauge the rate, but at the peak (5:30-ish EST?) I was seeing meteors about once every second with bursts of 6-7. It was hard to catch them all as they would appear in nearly every quadrant of the sky. After about the first few minutes I had already seen more meteors than I had seen in my entire life previously, so it was well worth the trip.:)
People have rights because they are human, not because they have been found not guilty
Amen.
It's not often that I find myself agreeing so strongly with an AC, but now is one of those times! The concept of Human rights is one of those crucial ideas that practically all of modern civilization is based on. I just assume that everyone understands this and then get shocked (with disturbing frequently) when someone in a developed nation (with internet access even!) clearly has yet to grasp it.
What hope have we for the Taliban to understand human rights when there are slashdotters that don't even understand them.
Slashdot Mirror
/joeyo, who has been landline free for a year and a half.
Secondly, there's the problem of spike sorting. There is, AFAIK, no fully automatic way to detect and sort spike trains from multiple-extracellular electrodes in real-time. (ie to be able to tell how many neurons are "talking" to any single electrode.)
Finally, the level of plasticity in the adult brain is an unknown quantity. Primate studies are suggestive, but there doesn't seem to be a consensus on how to best have a machine "talk" to the brain. Should we have the brain learn how to do it? Have the machine learn to do it? Some combination of these? What about for paralytics-- how do you train someone to use a very specific part of the brain. Remember that you're recording from at best a few hundred cells!
Probably surprisingly few if you have a good neurosurgeon. And if he is paralyzed to begin with it might not matter./joeyo
-- FORTRAN manual for Xerox computers
"No proper program contains an indication which as an operator-applied occurrence identifies an operator-defining occurrence which as an indication-applied occurrence identifies an indication-defining occurrence different from the one identified by the given indication as an indication-applied occurrence."
-- ALGOL 68 Report
"The '#pragma' command is specified in the ANSI standard to have an arbitrary implementation-defined effect. In the GNU C preprocessor, `#pragma' first attempts to run the game rogue; if that fails, it tries to run the game hack; if that fails, it tries to run GNU Emacs displaying the Tower of Hanoi; if that fails, it reports a fatal error. In any case, preprocessing does not continue."
--From an old GNU C Preprocessor document
/joeyo
Easy. The cat looks "cat-like" and the dog looks "dog-like." Whats the big deal? ;)
/joeyo
/joeyo
"Articles freely available online are more highly cited. For greater impact and faster scientific progress, authors and publishers should aim to make research easy to access"
/joeyo
Also it doesn't help that there is no general solution to the global optimization problem.
/joeyo
I love the onion. :)
/joeyo
Even more shocking, secure IMAP and POP does exist.
/joeyo
So did the Buddha r00t the universe too? Or did he just fall victim to the honeypot?
The simplest way would be if the brain had some sort of look-up table: when I see the ball at position X1, I move to position Y1; when I see it at X2, I move to Y2. Or more generally: position Xn -> Yn. In this way you could build up a detailed model of your environment and the mechanics of your interaction with it. However, it can be shown that this is most likely is not the way it works. Why? Generalization.
Tasks and environments which are learned in one situation are generalizable to others. This can be shown with prism glasses, rotating rooms, micro-gravity, macro-gravity, etc. Basically, in any situation in which the physics of the universe or the physics of the subject, or the interaction between the two is changed, the subject can adapt in a robust way that a table-lookup can't touch. Reza Shadmehr has some very interesting results on this topic.
So how else could it work? Moving up a level in complexity we get to what is known as an internal model. The internal model describes the mechanics of the universe and the bodies interactions with the universe. When the mechanics changes (eg prisim glasses) the model is updated via proprioceptivie information. The difference between this and the look-up table above is that it is represented in such a way that extrapolations to new situations are possible. We can mathematically represent such an internal model as a jacobian matrix, very similar to those that you may remember from your mechanics classes.
This does beg an interesting question though: how the heck is our brain able to quickly invert matrices? ;)
Another possibility is that the brain is actually "aware" at some level of the laws of physics and is doing calculus to figure out trajectories. This is also unlikely; there are simply too many degrees of freedom. Robot designers don't generate movement by solving laws of motion, they use feedback control.
(If you're familiar with control theory you might have been wondering about feedback control. Might not the brain be getting a real-time error signal and correcting its movement in the way that a robot would? It turns out that this is unlikely. Nerve conduction velocity is too slow so there is too much lag between the extremities and the CNS. If our motion were controled by feedback alone, smooth motion would be impossible. Clearly the proprioceptive error signal is there but it acts on a much slower timescale.)
CO2 + 4H2 -> CH4 + 2H2O
All you have to do is bring the hydrogen; the carbon dioxide is already there on Mars. And the reaction is exothermic, so you can do something useful with the waste energy too.
If you electrolyze the water you can produce more oxygen:
2H2O -> 2H2 + O2
Now for each unit of hydrogen that you bring to Mars, you get twelve units of methane/oxygen. And this is the simplest case, you can do better if you use some clever chemistry.
See Robert Zubrin's book, The Case for Mars for more information.
/joeyo
/joeyo
Now if they could deliver signals directly that caused the limbs to move in a coordinated fashion... well, that is another story.
/joeyo
yeah but it's clever. And it makes a group of boxen sound like cute animals. oxen or something... :)
Oh please, don't try to pass this opinion of yours off as truth.
Try alterslash.
You get the stories, the best comments, and a plot of the new comments and percent signal plotted verus time. It's great. I only log into slashdot now when I post comments.
/joeyo
I saw a few with color-- at least one was bright green and there were a few that were green-yellow and some that appeared to be redish. I don't know how much of this was an afterglow artifact and how much of it was real, but it looked stunning. :)
:)
My vantage point was Kerr Lake, NC. I went camping with some friends and we took a home-made dobsonian telescope to stargaze with prior to the shower. The conditions were about perfect. The sky was clear, there was very little light pollution, it was dry, windless, and actually pretty warm for mid-November.
I dont really know how to gauge the rate, but at the peak (5:30-ish EST?) I was seeing meteors about once every second with bursts of 6-7. It was hard to catch them all as they would appear in nearly every quadrant of the sky. After about the first few minutes I had already seen more meteors than I had seen in my entire life previously, so it was well worth the trip.
/joeyo
Amen.
It's not often that I find myself agreeing so strongly with an AC, but now is one of those times! The concept of Human rights is one of those crucial ideas that practically all of modern civilization is based on. I just assume that everyone understands this and then get shocked (with disturbing frequently) when someone in a developed nation (with internet access even!) clearly has yet to grasp it.
What hope have we for the Taliban to understand human rights when there are slashdotters that don't even understand them.
/joeyo