Domain: ucla.edu
Stories and comments across the archive that link to ucla.edu.
Comments · 1,051
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Re:No thanks, we are just fine w/o you.
"Slippery slope" is a logical fallacy
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Re:More info?
The Compton effect is definitely not responsible for cosmological redshift. Most tired-light models fail at least one of the tests in the preceding link. And links to a bunch of unpublished and uncited preprints on the arXiv are not terribly credible.
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Re:But what about the Horizon problem?
There is no epicenter like there is in an earthquake, but you can define any position at rest in the frame of the background radiation itself to be as good of an "epicenter" as any other for purposes of this discussion. The Earth doesn't meet this standard, because it's moving at a speed of 365 km/sec relative to the CMBR (hence the Doppler shift), but it probably doesn't matter.
Here is a good FAQ entry regarding the difference between the observable universe and the entire universe. -
Re:DUH! expanding from the center!
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Re:DUH! expanding from the center!
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Re:Physics data and theories - how suspect are the
You can never rule out the existence of a phenomenon that's screwing things up in an undetectable way. Indeed, if it has no detectable effect, who cares? But you can rule out alternatives that have side effects. For instance, you could postulate that the redshifting of light from distant galaxies is not due to recession in an expanding universe, but is instead due to some other mechanism which causes light to lose energy as it travels ("tired light"). But there are many ways that various specific tired-light models fail to be consistent with other observations. If two explanations give the same predictions for all observations that we can perform, we can never tell the difference between them, but often that's not the case, and we can rule out alternatives.
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Re:The difference between dark matter and dark ene
See also Ned Wright's cosmological constant FAQ.
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Bill Nye, Jill Tarter, & Astrobiology at UCLABack when I was co-president of the UCLA AstroBiology Society, I organized a big event for which Bill Nye was the headliner! He was great: he gave a custom-tailored talk to an audience of about 500, even though he'd gotten food poisoning in Indiana the day before! Here are pics from the event: http://homepage.mac.com/uniace/PhotoAlbum21.html
I've still got his voice on my answering machine! It'll be great to see him back on TV.
The other speaker at the event was Dr. Jill Tarter, Director of Research at SETI. Jodie Foster's Character in the movie, Contact, was based on Dr. Tarter. She was also a great speaker and cool to work with.
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Re:Okay, now it's official (slightly off-topic)
I'm glad someone realizes this.
And I'm at least consistent in my views here...
By the way, I was glad to see your reference to A Measure of Media Bias recently.
But then, most people are equally hypocritical and willfully ignorant in that realm as well. -
Probably not.. Yields are too goodYield data is hard to come by, but here's a business school case study with some hard numbers. Pentium 4 yields were around 60%, and DRAM yields were around 90%, in 2002. Pentium 4 yields are probably well above that point now, since that technology has matured. Note the comment in that paper that in DRAM fabs, at initial startup, yields may be as low as 5-10%, but rise to 90-98% once the fab is running properly. So that's where you put your effort, not into finding ways to use the rejects.
There have been moments in DRAM history when devices were made that were configured in some way during final test to work around bad spots. IBM did it for a while in the 1980s, I think. But with 90+% yields, it's not worth the added switching you need on chip to allow that. You could, in theory, use heavy ECC to tolerate a substantial defect rate. That's how CD-ROMs work, after all. But it's not necessary yet.
For a while, there was a market for DRAM with bad spots for use in telephone answering machines.
This is an idea that resurfaces periodically in the semiconductor history, but historically, the yields have always come up to acceptable levels.
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Re:Good Use for Importing Stationary Objects"...but science is not quite there yet"
Actually, it is. Well, since you said "uncalibrated" I suppose you are mostly correct, though I don't mind calibrating my camera, that's relatively easy to do. But as far as 3D-from-motion (single camera) I have (and have read) the literature and examples from both of the referenced sources, and just 3 weeks ago we got a demo here of working 3D-from-motion system from one of our research partners. It's actually quite impressive, about on par with the stereo system we have and with similar limitations (lighting sensitivity, sensitivity to calibration, etc).
It's true stereo isn't a "done deal", but from all the research we've been monitoring it seems we're over the hump of the curve and everything from now is likely to be minor improvements with a lot of work. There are fundamental limitations of stereoscopy (and 3D-from-motion) that I think we're very near to.
But, I should also correct the inference. By "everyone and their dog" I meant that it's been (and being done) by lots and lots of people. There are very few people doing the 3D-from-motion.
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Re:You were warned...
Funny you should mention that, late last week I just happened upon this article while doing some not-entirely-random surfing.
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just a policy based on a memo
I logged out to post this, because I am an Anonymous Coward.
The Federal Aviation Administration does have a policy against traveling without ID. But it is not a secret law. It is not even a federal law. It is just a policy based on a memo by someone at the FAA. The 3 branches of government do not feel the need to correct the FAA, because so few people complain. CFRs are trumped-up administrative rules. Only USCs are laws, and there are no USCs requiring passengers to have photo IDs for domestic flights.I know a little about governments and IDs.
The FAA policy reminds me of Florida Fish And Wildlife posting (everywhere) that it is illegal to carry a concealed gun in state parks. But the state attorney states that Fish And Wildlife has no statutory authority over guns and anyone with a conceal carry permit may carry in state parks.
I've had a similar problem with Walmart sporting goods managers telling me that it is against county law to sell ammo after 9 PM. It is not. It is just their store policy, but they want to use the excuse that it is a law.
The problem is not with the Federal government. The problem is with the general public. We need to have more people like John Gilmore. At a basic level, we're imposing this dictatorship on ourselves.
Perhaps we should start a petition to have the movie 1984 played on a TV network. Might wake up the sleeping public. Another step would be to have the Constitution and, at least, the first 10 Amendments printed on the back of our paper currency, not mystic, cryptic Masonic symbols.
But the US is hardly becoming a dictatorship. I consider this graphic as evidence of the health of our freedoms.
Got to love a government that trusts you to take a gun into a bank.
http://www.packing.org/state/index.jsp/all+united+ states
The reason that I voted for Bush/Republicans in 2004 is because Bush agrees the Second Amendment protects our individual right to own and carry guns.
http://www.nraila.org/images/Ashcroft.pdf
http://www.usdoj.gov/olc/secondamendment2.htm
I fail to see how an administration that supports the right to own weapons that can overthrow a government is the bogeyman of tyranny. For those that don't think that civilians with their "puny" guns could take down a hypothetical American dictatorship, consider that there are more than 240 million guns owned by 85 million civilians in the US.
The 2nd Amendment is the most liberal and radical law in history. http://www1.law.ucla.edu/~volokh/radical.htm
To really understand the tone of the 1st and 2nd, one should read the preamble to the 10 amendments. (Usually not taught in government schools, so most have never heard of it) "The conventions of a number of the States, having at the time of their adopting the Constitution, expressed a desire, in order to prevent misconstruction or abuse of its powers, that further declaratory and restrictive clauses should be added: And as extending the ground of public confidence in the Government, will best ensure the beneficent ends of its institution."The first phrase of the 2nd is a declarative. It was the style of writing legal documents in the late 1700's to include a preamble. The preamble states a purpose, not a limitation on the language in these government charters. The phrase "well regulated" means well-trained and well-equipped, in proper working order. Ex: "a well regulated clock." "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
Interestingly, the Militia Act of 1792 was law until 1903 (updated by 10 USC). The Militia Act of 1792 stated "That each and every free able-bodied white ma -
Re:Black holes?
Personally, I'd love to see a ground-based scope on the far side of the moon to replace hubble, but I'm probably just dreaming.
Ok, first of all, somebody please mod this parent up for that thought; I've been hoping for someone to suggest pretty much the same thing for a long, LONG time (it also sounds like a pretty good place for a RADIO telescope; not too many electric shavers and "Mr. Microphones" on the Moon!)
Second, regarding AO, I just happened to catch about ten minutes of a presentation titled "Unveiling a Black Hole at the Center of the Milky Way" (carried on DISH Network at channel 9412) and the Q&A turned to AO (I presume a good bit of the lecture dealt with AO, from the way the lady talked, but I'm not sure...) If you'd like to check it out, apparently the entire lecture (recorded Oct. 30'th, 2003) is available here (along with a handful of other juicy-sounding titles...)
And on the ground-based -vs- Hubble debate, I say "I dunno, if we're willing to raise money for a television show then surely there's somebody out there willing to organize a "bake sale" or something for such a useful piece of hardware...whether the money's used to build a completely new scope (somewhere, ANYwhere) or if it's used to blast Hubble all the way to the nearest 'Lagrange point'." (Yeah, yeah, I know; now I'm dreaming...) -
Re:Pipe Dream
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Re:Pipe Dream
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Re:This is BS - Dark Matter is FictionThat book you cite is from 1991. The field of cosmology has exploded since then. But even in 1991, the conclusions in it were known to be incorrect. But don't take my word for it, take Ned Wright's, from UCLA:
http://www.astro.ucla.edu/~wright/lerner_errors.h
t mlAnd one word on theories. The Big Bang, gravity, evolution... all fit under the category of theories. No good scientist will argue with that. But the thing about these theories - for everything we've thrown at them so far, they work. They hold up. They may need modifications, tinkering (e.g. gravity has yet to be married to quantum mechanics), but the foundation is very solid.
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Re:Light Speed Travel
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Re:Lots of resources for GtD
I forgot to paste in some of my links:
- Excellent article with many links at the bottom from 43Folders - http://www.43folders.com/2004/09/getting_started.h tml
- http://www.minezone.org/wiki/MVance/GettingThingsD one
- Tons of Links - http://www.bol.ucla.edu/~smerino/gtd/gtd-resources .html -
Re:UnfortunatelyMost of the people live on one coast or the other, so our population density for those regions isn't that different.
To quote: Blah, blah, blah. 10 minutes or less of fact checking would have saved you a ton of bull. There are only four states on either coast (well, on the East Coast really) that come close to the population density of Japan (this is in 2000 and I'm pretty positive it holds true today with minor variation). Here, as of 2000, are the population densities of East and West coast states versus Japan:
All figures are people per square mile.
- Japan - 858
- New Jersey - 1134
- Rhode Island - 1003
- Connecticut - 703
- Mass. - 810
And from here it just goes downhill: - California - 218
- New York - 402
- Oregon - 36
- Washington - 89
- Florida - 296
- Maryland - 542
- Maine - 41
- Georgia - 141
- Virginia - 179
And so on and so forth. So, basically, the facts support my assertion that population density is still not close enough to Japan's to justify comparison _based on that fact alone_. Even consenting that a large portion of people on both coasts live in large cities the density is still off by a factor or two. I'm all for FTTH being rolled out by municipalities acorss the US. I'd kill (well, ok, maybe not kill but asswhoop) to have faster broadband access in my region but I still think it comes down to "who is going to make the money?"
You can also see some comparisons of population density here. This is a
.pdf file. -
Yes, a threat, also: an opportunityConsidering the mass (8e+10kg estimated), orbital inclination (3.3 deg), and eccentricity (.191276) 2004MN4 is a pretty good candidate for exploration .
The probability estimate needs to be refined to account for the Yorp effect.
Further observations will show approximately what 2004MN4 is made of. I have hope that it's a rocky body with quality ores such as nickel/iron... but only a Deep impact style probe would give us truly hard data.
Now, if you look at the orbital plot, you'll note just how close this rock is right now... and how close it gets not just on april 13, 2029.
While the newspapers and the slashdot articles are focused on the potential impact energy, (m*v), I'm far more interested in m.
This rock has more mass than mankind has put into space since the beginning of the Space age; far, far more mass than is projected to be in the International Space station. And there it goes by, whizzing overhead, on near miss after near miss, for the next couple centuries.
Assume 2004MN is 1% nickel. Earth value of 8,000,000 tonnes of nickel is: 12,200,000,000 US dollars. (well, until the nickel futures market crashes harder than this asteroid will). Value of any material, if it were in earth orbit, is 10,000/lb and that's too many zeros for me to type here. For just the nickel. Oxygen is even more valuable. Slag is valuable.
If we just had a booster on the pad with enough oomph, we could get a probe there in a matter of weeks.
IF this asteroid contains valuable materials (be they platinum, iron, nickel, gold, oxygen, or carbon), it would be a bonanza for mankind's space efforts.
Divert Dawn (launch date 06/06), or Deep Impact (launch date 01/12/05). Let's Find out!
This asteroid (and many other NEAs like it) is not just a threat, but an opportunity. It's an opportunity to get a leg up into space.
Can we afford to take a look? Can we afford not to?
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Re:I have said it before and I'll say it again...
Those who want the law reformed need to posit credible alternatives, alternatives that ensure that movies (and music and books etc) can still be made, before arguing that there's something inherently unjust in having to pay to have access copyrighted material
If what you mean by "Credible alternatives" are ways that ensure that the same old drivel will be produced, and distributed through the same channels in the same form then alternatives is hardly the appropriate word.
If you are really interested in why there is no reason why the generation and dissemenation of ideas, including in the form of movies and music does not have to involve draconian enforcement of legaly induced scarcity, I suggest you read:
http://levine.sscnet.ucla.edu/papers/pci23.pdf
for starters.... -
Re:University of California is anti-digitalHere's some links to policies, which appear pretty uniform for all UC campuses--that is you pay a fee for reproduction of public domain works in their possession. I've tried all 3 libraries and they either say no, or don't even bother replying (for both personal visits and a snail mail letter): A FOIA may help, if it applies to UC. I'm not familiar with it, but isn't that a federal law that applies to the U.S. government. I don't know if California has an equivalent. IANAL, but I'll look into it and see if there's a California state version of FOIA.
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R (GNU S)
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Re:Let's make something perfectly clear
Presenting the tools to a user to allow them to infringe on somebodys copyrights: Legal
Have you heard of the DMCA? You may wish to take a look at this article. In paricular:
[The DMCA o]utlaws the manufacture, sale, or distribution of code-cracking devices used to illegally copy software.
Sad but true.
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Re:Thanks Zak, you made this thread Informative
Uncertainty principle, as in Quantum Mechanics?! That's a really funny one! The only thing fundamentally limiting signals transmission is noise, which in electromagnetic transmissions comes in its most unavoidable form from thermal noise. There are other sources of "noise" or "interference": depending on the environment, interference can come from other communicating devices, a car's engine ignition sparks, thunder, a static discharge, a microwave oven... And worsening it all, media also always attenuate the signal, more or less, therefore weakening the Signal-to-Noise ratio which along with the available bandwidth determines the theoretical capacity of the transmission system. The uncertainty principle has nothing to do with it.
Any good introductory course in Digital Communications will cover this, and introduce the notion of QAM and constellations in passing. May I suggest this Digital Communications OpenCourseWare module (viva MIT) or, for a gentler introduction that might not be as complete, this set of slides (viva University of Cambridge).
And once you've read all about it, be sure to write up an entry about it in WikiPedia ;-) -- or to update this one.
Radio systems utilizing multiple antennae (MIMO), may "trump" this to some extent by playing on the fact that spectrum is a three-dimensional medium and not a one-dimensional medium (contrary to twisted pairs or coaxial cables). On that, you may want to read this intro. -
Re:incentive is not always about moneyIndeed! I was just reading an article (actually a press release about a longer article) about the "physics" of
how regular word of mouth compares with "opinion leader" word of mouth (the latter being ie a review in the New York Times or a review/article link on Slashdot) in the making of bestselling books.
/. wasn't mentioned in the above-linked article, but it was mentioned in the blurb that I followed to it.
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Re:delaying the inevitable?
Depending on whether you consider the surrounding areas "London", the metropolitan at the time was served by more than just two water companies. The data compiled by Snow himself lists several.
Yes, most people at the time still thought "contaminated vapors" were involved. But I don't think it is fair to chalk up the chilly reception of Snow's idea to any fault of Snow. The scientific vigor of Snow's statistical study was largely undervalued by the people of the time. In his defense, Snow's study was "On the Mode of Communication of Cholera" not on the cause of cholera itself. In this goal, it is hard to argue Snow was not successful. When you are aware of *how* a disease spreads, the nature of the disease is largely irrelevent in any effort to contain an epidemic.
The point I wanted to make is, a single managing entity has much more freedom to act decisively. Let's say during snow's time, one or more of the water companies heeded Snow and actually took steps to halt the spread of cholera from their own pipes. The disease would still be spread in the city by those company(s) which chose to do nothing.
Today's Internet, by it's very nature, is fractionaly owned and maintained. But if residential access was centraly managed like a utility, it would exist as a public service for a municipal resident rather than a means for a private business to generate profit. The level of responsiblity would demand that accessibility and service approach the standards of water or gas or electricity providers.
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Re:that's not really responsive
at least the approximate date it happened
There were a few attempts after Germany's surrender (which made it clear that Japan's victory was absolutely impossible), but the final and most important was on July 26th, when Japanese agents (operating from neutral Switzerland) gave their response to the Potsdam Declaration.
It isn't some big secret, so you can read more in Wikipedia or Google.
(You saw my other message re the emperor's survival vs "unconditional surrender") -
Re:First Heinlein Reference
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Try a Levitron
If you want to try something really cool for Christmas, try out the Levitron - a levitating magnetic top. Once you get the hang of how using it, it's absolutely the coolest thing. It's very non-obvious from a physics perspective, in fact there have been several papers written on how it works (here's one).
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Re:What about...Good ideas! Related to the simple controller concept, check out what they are doing over at the Center for Embedded Networked Censors, they are using Wi-Fi for a lot of sensing systems - a bit like the "smart dust" concept that hits the news every so often.
--
carbolic/Mike O.
Wi-Fi Toys -
Re:And what'll wean us from nuclear power?
Just one class 9 meltdown .
Each plant operator is only required to carry $300 Million of private liability insurance per plant. In total the nuclear industry carries only 8.5 Billion dollars of insurance, enforced by a form a government socialism. (Post accident levy).
For an estimate of REAL damages [nirs.org].. take a look a Chernobyl catastrophe
"If accident damages exceed that amount, taxpayers will be asked to make up the difference. Compare that to the 1982 Sandia National Laboratories study (CRAC-2 [ccnr.org]), which projected economic damages of up to $300 Billion (in 1982 dollars) resulting from an accident at the Indian Point, NY reactor site. The 1986 Chernobyl catastrophe already has cost Russia, Ukraine and Belarus some $300 Billion, and the costs-from interdicted land, from radioactive waste disposal, from ongoing health effects-mount daily.";
Folks, that's $300 Billion in 1982 dollars!! Care to guess what that number is today?
I'll bet that it's in the Trillion dollar range."Moreover, no other hazardous industry has such a subsidized insurance scheme. "
For the time being, I suggest keeping our Nuclear power source a nice safe distance away, one AU is a good number, and embark on a distributed program to harness the energy it bestows to us all (wind, solar). -
Use of the word "liberal"This is something that has always bugged me as well. Over here in Belgium "liberal" is used to designate those who promote business, the ones that are on the other side of the socialists as it were when it comes to the economy, employment. This struck me as weird because the word itself has a Latin root that means free. This didn't jive with this whole business-capitalism spiel.
Then, by chance, I happened upon a very interesting article by Phil Agre: http://polaris.gseis.ucla.edu/pagre/conservatism.h tml. It's called "What is conservatism and what is wrong with it?". It actually goes into the history of how language was coopted and twisted into artificial meaning. It's long but definitely worth a read. -
The first Bit to travel over ARPANET?So was the first ever bit to travel over the Net a 0 or a 1??
Assuming that the Honeywell-based IMP was a using a 7-bit ASCII-like encoding without checksum bit and transferred bit sequentially from most to least significant bit, then the first sequence was 1001100. But I guess it was perhaps rather based on a five-bit teletype scheme.
There wasn't much info on the DDP-516's homepage about that. But I like this quote: "The Honeywell DDP-516 was chosen for its high clock speed (aprox. 1.1 MHz) and expandability"
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Try Nuggets , the mobile search engine. We answer your questions via SMS, across the UK. -
No cooling?
From the UCLA "A key attribute of the new technology is that it can produce mid-infrared radiation without any cooling," Jalali said
Now this sounds really intersting, how come they dont need cooling?
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Re:Someone Think Of The Students...Or, often more importantly, of the faculty.
I teach at a good sized state university, and we were well ahead of the curve in being "wired" (we could easily answer "yes" to almost all the questions on the forbes survey). But I have colleagues who don't know how to use their computers. While there are attempts to train faculty and draw them more into the information age, there are still far too many (usually older) faculty members (and staff) who are out of touch technologically. Department pages are very slow to be updated on the web (if they exist at all), students freely plagiarize from online sources knowing their professor won't use google to catch them, and computer labs are cesspools of viral activity because the OS's aren't kept up to date.
What's worse, the university has bought into inflexible proprietary software solutions such as PeopleSoft, WebCT, and Blackboard to try to manage tasks which would be much better served by more flexible tools. I don't know as much about Peoplesoft (other than that I hate using it and it doesn't always work with my Mac), but my experience with the online teaching tools is that we would have been much better off with open source solutions like classweb, being developed at UCLA.
But of course it's a lot more difficult to measure such things on this sort of survey.
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Re:Isn't that...
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Re:Encoded Packets doesn't Solve Problems
I suspect the exact details of the erasure codes they're using can be found here, which by no coincidence is written by Petar Maymounkov and David Mazieres (both the authors of the original Kademlia paper). A good primer for erasure codes would be to read up on Reed-Solomon codes, which seek to provide similar end-results as erasure codes.
Rateless codes are important because they are the first step to a "digital fountain" model of data transfer. The idea is this: say you have a file of 10KB. Using erasure codes, you can "oversample" this file -- that is, turn this file into 40 1KB chunks. Now by collecting ANY 10 of these 1KB chunks, you can reconstruct the original file.
The reason the digital fountain is so cool (and the reason for its name) is because it would make the most amazing BitTorrent client ever. Why? In BitTorrent, you're doing things like choking/unchoking, aggressively seeking the rarest pieces, and hoping that some guy who has the ONLY COPY of piece X doesn't leave the network before it is replicated. Using Erasure Codes, everyone would just blindly get whatever data is sent to them (where each data unit is an "oversample"), and blindly forward it on all outbound links. But if you're getting data in this manner, isn't there a chance you'd get the same piece of data twice (which is like getting the same piece twice in BitTorrent, which is no use)? If you oversample enough, you can make the chance of this happening approach 0. Note in this scheme, there's no choking or unchoking here (so you'll never go through a period of time on a rare torrent where EVERYONE is choking you, and your download rate is 0KB/s), and you don't have to worry about that one guy leaving the swarm with some critical piece -- not just because you can always reconstruct it, but also because that piece is no more critical than any other.
It's beautiful, really. So why aren't we doing it? Simple -- erasure codes are computationally expensive to compute, although
they're getting easier as new sorts of erasure codes are being developed, and PCs get faster. The first big breakthrough was with Tornado codes, if I remember correctly. Anyway, we'll see what the future holds...
- shadowmatter -
Re:Encoded Packets doesn't Solve Problems
I suspect the exact details of the erasure codes they're using can be found here, which by no coincidence is written by Petar Maymounkov and David Mazieres (both the authors of the original Kademlia paper). A good primer for erasure codes would be to read up on Reed-Solomon codes, which seek to provide similar end-results as erasure codes.
Rateless codes are important because they are the first step to a "digital fountain" model of data transfer. The idea is this: say you have a file of 10KB. Using erasure codes, you can "oversample" this file -- that is, turn this file into 40 1KB chunks. Now by collecting ANY 10 of these 1KB chunks, you can reconstruct the original file.
The reason the digital fountain is so cool (and the reason for its name) is because it would make the most amazing BitTorrent client ever. Why? In BitTorrent, you're doing things like choking/unchoking, aggressively seeking the rarest pieces, and hoping that some guy who has the ONLY COPY of piece X doesn't leave the network before it is replicated. Using Erasure Codes, everyone would just blindly get whatever data is sent to them (where each data unit is an "oversample"), and blindly forward it on all outbound links. But if you're getting data in this manner, isn't there a chance you'd get the same piece of data twice (which is like getting the same piece twice in BitTorrent, which is no use)? If you oversample enough, you can make the chance of this happening approach 0. Note in this scheme, there's no choking or unchoking here (so you'll never go through a period of time on a rare torrent where EVERYONE is choking you, and your download rate is 0KB/s), and you don't have to worry about that one guy leaving the swarm with some critical piece -- not just because you can always reconstruct it, but also because that piece is no more critical than any other.
It's beautiful, really. So why aren't we doing it? Simple -- erasure codes are computationally expensive to compute, although
they're getting easier as new sorts of erasure codes are being developed, and PCs get faster. The first big breakthrough was with Tornado codes, if I remember correctly. Anyway, we'll see what the future holds...
- shadowmatter -
Re:Encoded Packets doesn't Solve Problems
I suspect the exact details of the erasure codes they're using can be found here, which by no coincidence is written by Petar Maymounkov and David Mazieres (both the authors of the original Kademlia paper). A good primer for erasure codes would be to read up on Reed-Solomon codes, which seek to provide similar end-results as erasure codes.
Rateless codes are important because they are the first step to a "digital fountain" model of data transfer. The idea is this: say you have a file of 10KB. Using erasure codes, you can "oversample" this file -- that is, turn this file into 40 1KB chunks. Now by collecting ANY 10 of these 1KB chunks, you can reconstruct the original file.
The reason the digital fountain is so cool (and the reason for its name) is because it would make the most amazing BitTorrent client ever. Why? In BitTorrent, you're doing things like choking/unchoking, aggressively seeking the rarest pieces, and hoping that some guy who has the ONLY COPY of piece X doesn't leave the network before it is replicated. Using Erasure Codes, everyone would just blindly get whatever data is sent to them (where each data unit is an "oversample"), and blindly forward it on all outbound links. But if you're getting data in this manner, isn't there a chance you'd get the same piece of data twice (which is like getting the same piece twice in BitTorrent, which is no use)? If you oversample enough, you can make the chance of this happening approach 0. Note in this scheme, there's no choking or unchoking here (so you'll never go through a period of time on a rare torrent where EVERYONE is choking you, and your download rate is 0KB/s), and you don't have to worry about that one guy leaving the swarm with some critical piece -- not just because you can always reconstruct it, but also because that piece is no more critical than any other.
It's beautiful, really. So why aren't we doing it? Simple -- erasure codes are computationally expensive to compute, although
they're getting easier as new sorts of erasure codes are being developed, and PCs get faster. The first big breakthrough was with Tornado codes, if I remember correctly. Anyway, we'll see what the future holds...
- shadowmatter -
Re:Encoded Packets doesn't Solve Problems
I suspect the exact details of the erasure codes they're using can be found here, which by no coincidence is written by Petar Maymounkov and David Mazieres (both the authors of the original Kademlia paper). A good primer for erasure codes would be to read up on Reed-Solomon codes, which seek to provide similar end-results as erasure codes.
Rateless codes are important because they are the first step to a "digital fountain" model of data transfer. The idea is this: say you have a file of 10KB. Using erasure codes, you can "oversample" this file -- that is, turn this file into 40 1KB chunks. Now by collecting ANY 10 of these 1KB chunks, you can reconstruct the original file.
The reason the digital fountain is so cool (and the reason for its name) is because it would make the most amazing BitTorrent client ever. Why? In BitTorrent, you're doing things like choking/unchoking, aggressively seeking the rarest pieces, and hoping that some guy who has the ONLY COPY of piece X doesn't leave the network before it is replicated. Using Erasure Codes, everyone would just blindly get whatever data is sent to them (where each data unit is an "oversample"), and blindly forward it on all outbound links. But if you're getting data in this manner, isn't there a chance you'd get the same piece of data twice (which is like getting the same piece twice in BitTorrent, which is no use)? If you oversample enough, you can make the chance of this happening approach 0. Note in this scheme, there's no choking or unchoking here (so you'll never go through a period of time on a rare torrent where EVERYONE is choking you, and your download rate is 0KB/s), and you don't have to worry about that one guy leaving the swarm with some critical piece -- not just because you can always reconstruct it, but also because that piece is no more critical than any other.
It's beautiful, really. So why aren't we doing it? Simple -- erasure codes are computationally expensive to compute, although
they're getting easier as new sorts of erasure codes are being developed, and PCs get faster. The first big breakthrough was with Tornado codes, if I remember correctly. Anyway, we'll see what the future holds...
- shadowmatter -
Non sequitur
People much smarter than you already determined that the K-T boundary is uniformly deposited (in terms of time) across the earth, no matter which craton you examine, and it occurs at the same point in time as a significant biomass die-off.
This indicates that a extreme amount of dust and ash must've been airborne for many years, blocking much of the sunlight that would normally enable plant life to flourish. While it is entirely feasible that dinosaurs were in decline prior to this time, the event that killed them is the same one that ultimately created the K-T.
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Re:Finally
So now do us the favor of defining "unathorized" sharing of files, would you please?
I figure we can start with the decision of the courts that companies are "authorized" to create and distribute software that facilitates sharing.
Then we can move on to the concepts of "fair use" and "first sale" which "authorize" users to make copies for their own use; let their friends and relatives read, listen to, or watch them; and resell copies they have legally purchased without paying royalties.
Oh, on the way I think we should touch on the "No Electronic Theft Act" which "authorizes" users to legally share up to $2500 worth of material with anyone*.
So, please enlighten us, oh great master of copyright wisdom!
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*(Note: the DMCA may have superceded some or most of the provisions of the NETA. IANAL, etc.) -
Re:control
In my personal opinion the slippery slope arguemnt is nonsense.
Not always; see this paper. What can happen is that once the infrastructure is established for "mild" surveillance or censorship, the cost to implement more invasive control is now lessened, which may cause people to now support it whereas they wouldn't before. (That's not a good explanation, the article is much better).
Now in some cases you can accurately predict peoples motives such as the movie and porn industry want to do whatever it takes to make money at any cost to the consumer just as the cigarette and alcohol companies do.
Gosh, just like the computer, telephone, and ball bearing companies.
Do people have a choice?
Yes.
What do you mean by "consenting"?
Chosen freely when one is in a sound mental state.
Suicide is "consenting" but it is a decision made when your deck isn't full.
Always? What about someone with a terminal disease in a great deal of pain?
How about being in a porn video? How can you ensure that the decision is informed and isn't made under duress?
How do you ensure that anything anybody does isn't being done under duress?
There are whole other sides to the everybody look at porn arguement. It destroys people but do you care?
I care about preserving the freedom to pursue goals that others may disapprove of, provided they don't harm anyone else. I also care about preventing moral busybodies from enforcing their personal beliefs at gunpoint. -
Re:Corporate switchAs in the IBM XL compiler that has been out for a while now? http://airto.bmap.ucla.edu/mt-static/know/archive
s /2004/08/fsl_runtime_com.php and http://images.apple.com/science/pdf/xl_c_compilers google search for IBM XL G5.
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Re:None of you appear to understand the issues.You're right of course, except for the fact that I DO live in Europe. That, and the fact that the rest of your post had nothing to do with what I said. First of all the european version of the DMCA that I was referring to is actually called the European Union Copyright Directive and an article from the Register from April 30th 2002 actually refers to it as being more severe than the US one. I quote:
The directive, which was approved last year, extends European copyright legislation so that it is even more restrictive than America's controversial Digital Millennium Copyright Act (DMCA), critics argue. National governments have until December 22 to incorporate the directive in national legislation. If it goes through unmodified, the EUCD would make it a criminal offense to break or attempt to break the copy protection or Digital Rights Management systems on digital content such as music, software or eBooks. As it stands, the EUCD may lead to a rerun of Dmitri Sklyarov's prosecution, prevent teachers copying materials for their students or other legitimate uses of copyright material, opponents believe.
Now I know the British would like to consider themselves somehow above and beyond the rest of the EU but the fact is that your local version of the EUCD can only be more restrictive. As a matter of fact ANOTHER article (once again by the Register) points out that the british implementation may be worse.
Other than having pointed out that you suspect I may never have set foot outside of the States, you also were kind enough to have explained to me that the EU and open borders is nothing new. How right you are. I never mentioned any thing to the contrary. I DID suggest that the reason for the EUCD may have been a trade agreement. Oddly enough that seems to be something that Eurorights.org would agree with. They say:
The source of the law protection of 'technical protection measures', are the two WIPO treaties from December 1996. Note that the WIPO treaties require law protection for technical measures only when they deny copyright infringement The EU copyright directive is thus overbroad.
WIPO Copyright Treaty, Article 11 WIPO Performances and Phonograms Treaty, Article 18
As far as the rest of your reply, the US is already aware of the threat renegade IP nations may pose, and already have a watchlist with 14 other economies (including the EU). An Asia Pacific Media Network story about it says:
Although Taiwan amended its copyright law in June 2003, several provisions remain deficient," the trade representative's report said, without giving examples. The report noted that a promise by the government in February to seek improvements in the copyright law has not yet been fulfilled. Taiwan has been on and off the piracy list since the early 1990s. In 2001, after a three year gap, the country was placed back on the list, where it has been ever since. The dispute between Washington and Taipei over piracy is the biggest irritant in bilateral economic relations, and has quashed hopes that Washington would sign a free trade agreement with Taiwan. The two countries also have disputes over telecommunications, pharmaceuticals and rice imports, but heavy pressure on the US government from the entertainment industry, which claims it loses several billions of dollars a year due to piracy in Taiwan, has kept the issue in the forefront. The Ministry of Economic Affairs yesterday expressed regret and discontent over the US government's decision. "The US government ignored our efforts in passing the new Copyright Law, a
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Re:The War on Drugs funds Terrorists
It's almost useless to preach this approach since it is proven beyond doubt. The problem is that authorities want to have something in hand against those taking the risk to take illegal drugs. This is a dangerous part of society. Put them in prison. They are political prisoners. Did you know that the US has a larger part of it's population in prison than the Soviets ever had? Or any other part of the world?
The US are a aristocracy and it wouldn't stay that way just because, it has to fight hard to stay an aristocracy. -
Be afraid if the volcanoes ever stop
Subduction zones (like those off the west coast of America) and volcanoes (such as St. Helens) are a big part of the long-term carbon cycle of the planet. Left to its own, life and chemical processes on this planet would convert all the atmospheric carbon into calcium carbonate that would be trapped in rock on the bottom of the ocean. Subduction zones and volcanoes reprocess this rock into CO2.
Once the Earth's crust cools enough, it will lock up and stop the cycle and CO2 will inexorable drop in concentration. I can't remember when this is predicted to happen, but I believe it is scheduled to occur before the Sun becomes a red giant. Of course, I'm sure our descendants (assuming we have them) will invent their own C02 extract factories to keep the Earth nicely carbonated when the time comes. -
Re:Terraforming or ecosynthesising mars
Unfortunately for this hypothesis, Venus has no magnetosphere, experiences much stronger solar wind than Mars, and has no shortage of atmosphere.
So Mars' lack of atmosphere is likely due to a combination of factors, with the lack of magentosphere being perhaps necessary but hardly sufficient. The question for terraformers is whether or not it is possible to create and sustain an environment like the one we have on Earth via biological means.
It is worth noting that in the absence of life, Earth would be a lot less habitable than it is. That is, life on Earth has created conditions that are suitable for life on Earth. Or more correctly, life on Earth has found relatively open evolutionary niches due to the actions of other life on Earth. The most obvious thing like this is oxygen, which would weather out of the atmosphere in a few million years were it not a waste product thrown away by plants.
--Tom