Tuesday, January 25, 2005


Every now and again I take notice of the passage of time itself. Most recently I was drinking a sip of coffee and then suddenly the ephemeral, knife-blade like flow of time became the prominent center of my attention: I 'watched' myself take the sip, and then sat there and 'felt' that moment slide inexorably away - first the sip was just a few seconds ago - almost close enough to 'touch', and then it steadily drifted further and further away.

It then occured to me that it didn't necessarily have to be like that for a conscious being. Say you have physically downloaded all the neural patterns of your brain into a very advanced computer using some sort of fantastic futuristic nanotechnology. You could then change the programing of your own mind. In particular, imagine watching 2 movie screens right next to eachother, which are displaying the same events, only there is a small delay in the second screen. You could then have a huge series of such screens, perhaps each one delayed by one frame, so that you would be simultaneously experiencing an entire smooth chunk of time flowing into the future, instead of just the razor-thin 'present' that we have always been constrained to. Naturally we can't realistically follow more than a couple screens, but in this new malleable brain you could multiply the structures of your visual cortex a thousand times over, feeding each copy a slightly more delayed image.

And that would just be the beginning of the fun. Next, in order to further differentiate the different moments in time, perhaps you could derive whole new types of colors that would be used at different points in the segments of time that you simultaneously experience. Imagine watching a sunset, say with a cloud up high that reflects a deep red color that remains fairly constant during the time segment (say just a minute for now) that you are currently experiencing. You can then first imagine changing that red color continuously throughout the segment, so that the leading edge is the red we are familiar with, but it morphs into orange and then yellow, and so on so that it is purple by the end of the minute being simultaneously experienced - the color changes adding more depth to the range of time. But of course we can't steal from the other colors, so red would have to blend into some new color red2 which would become red3 further back in the segment and so on, with yellow and green and all the others also simultaneously evolving into yellow2 and green2 and so on.

Wednesday, January 12, 2005


A link from plastic on next generation television technology got me thinking. The nanotube aspect is cool and they've done some work on it here at UNC - essentially the ends of the tubes are very sharp, and thus when a voltage is applied there is a very strong electric field at the tip so they eject electrons easily.

In particular, the idea of these enormous televisions with possibly very high resolutions got me thinking of a really cool (and very expensive) art project you could do. Imagine a flat circular television some 10 feet in diameter with a per-square-centimeter resolution like a computer monitor, so that the whole thing would need some 100 million pixels or so. You'd have to have a mini-supercomputer just to process the data. And the image would be coming in from some big cluster of video cameras somewhere else in the world - let's say for the first one a skyscraper in Tokyo looking out over the city - which would be seemlessly spliced together for the super-high res. TV. And that would be it - it would broadcast that view 24 hours a day, 365 days a year, the webcam to end all webcams. You'd have the TV set in a thin seemless metal disk, perhaps on a pedestal set 3 feet off the ground, otherwise completely freestanding out in some public space, and it would be just like a wormhole portal to another place like you read in science fiction. The key would be the huge resolution - it wouldn't be like staring at a computer image on a screen, it would be like you were really there yourself - you could watch the clouds slowly morph and the shadows creep as the sun moved through the sky, and all the people and cars moving on the streets below. You could have another image on the opposite side of the disk, maybe a live feed looking up into the Himalayan mountains, and there could be other disks in the public space, looking out on the beaches of Hawaii, the city of Cairo with the pyramids in the background, the Canadian rockies while it's snowing, maybe one in Athens with the sun setting. Also, if you could get a live continuous feed of a low earth orbit satellite looking down on the earth that would be awesome - in fact, since this would take a while to be realized, maybe the opposite side of that disk could be a continuous feed of whatever galaxy or quasar the James Webb space telescope was currently observing.

Saturday, January 08, 2005

No more free lunch...

Here's a nice article by Herb Sutter making the case that further advances in computing power will be gained by developing multiprocessor technology, as opposed to continuing to ramp up the GHz. Apparently Intel is planning on creating chips with hundreds of cores eventually. Which is fine by me! Programming for parallel machines is somewhat trickier, but is natural enough once you get used to it. Say your program is looping over discrete time steps, with different nodes handling different areas of the computation (perhaps subvolumes in a 3-D model). Each node in turn will likely need to both work on data that will be sent to to other nodes (perhaps boundary conditions), and also work on completely internal data. It then makes sense to do the boundary calculations first, send off the results through the network, then work on the internal data, and by the time that is finished, the boundary data from other nodes should have arrived, allowing the next time step to immediately proceed. There are all sorts of tricks to be invented, and most programs that need huge amounts of processing power can be largely parallelized. Vector processing should be kept in mind too - ClearSpeed's CSX600 chip gets 50 Gflops running at 250 MHz with 96 processing elements - and all that with under 5 watts of power. That would get you to 100 Tflops - the current peak for supercomputers, and the estimated power of the human brain - with only 10,000 watts (which would be about 100 times less efficient than the human body - not bad though!). A.I. research, in particular, should be able to thrive on multiprocessor systems, since the human brain itself is a paragon of parallel design, with some 100 billion neurons, each one connected to some 1000 others.

Wednesday, January 05, 2005

Junk DNA?

Science magazine's # 5 story of 2004 is about the growing realization that much of the so called "junk DNA" which doesn't directly code for proteins (some 95% of the genome), does in fact provide important gene expression regulation functions, as well as code for transposable sequences that can jump around the genome, and for tiny RNA molecules (i.e. ncRNA - noncoding RNA, instead of messenger RNA for example), among other things. In fact, the complexity of an organism doesn't appear strongly linked to the number of genes it has (we're down to ~ 20,000-25,000), but in fact is linked to the percentage of the DNA that is noncoding (humans - highly complex mammals - also have a relatively high percentage of non-coding DNA). See for example: Taft and Mattick's paper, from the Quantitative Biology section on arxiv. There's a website dedicated to the subject too: Noncodingdna.com. The tiny RNA molecule coding sequences are particularily amusing - one of the theories for the origin of life is the RNA World hypothesis, which holds that RNA strands were the beginning point for life, since they can both self-replicate and also catalyze some chemical reactions like proteins. Perhaps these tiny RNA molecules are a 3 billion year old link to the origins of life on earth.

I've also had a pet theory for a while now that the non-coding DNA sections are important in accounting for all the subtle differences between people. When it is not being actively replicated or translated into RNA, DNA is coiled up tightly and wrapped around spool-like histone proteins. Thus the idea is that the differences in the A-T and C-G hydrogen bond strengths and the frequencies with which these base pairs occur in the junk DNA surrounding a given gene will subtly affect how easily the DNA is uncoiled and thus slightly affect the expression rate for that particular gene. This could then lead to, say, all the subtle variations in facial structures between different people (which our brains are so primed to detect), or perhaps partially account for differences in the inherent affinities of different brains. Presumably this could become testable after we gain more understanding in designing DNA and in protein folding and function.

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