Domain: sunysb.edu
Stories and comments across the archive that link to sunysb.edu.
Comments · 162
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Re:DORKS!
Mr Fancypants...let me guess, you got that nick serving time at Rikers... so, did the salad taste good, mr. fancyfaggot?
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By open proxy?I suffer from a disease known as Munchausen syndrome by open proxy.
Nice one. For more about the "actual" syndrome, check out this book description.
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Re:Sci Fi is often closer to reality than we thinkUnlike Aluminium it does not easily oxidise and rust
The oxide of aluminium that forms when it oxidises in air is the same size as the aluminium metal and so forms a protective layer. So Aluminium doesn't exactly rust like iron alloys. See here for more details...
I'd guess that it's Francium's very light weight to strength ratio that you're talking about, but I don't think it is light, according to this:
Francium does not have any stable isotopes. There is at most one ounce of francium in the whole earth at any given time as a result of the decay of other radioactive elements. It is the most unstable of the first 103 elements in the periodic table. Its longest lived isotope has a half life of 22 minutes.
Despite its radioactive complications, francium is the heaviest simple atom.And on the Ford website a result for searching from Francium:
Search Results
Results for: francium
Sorry no matches were found.Was this a joke, or can you provide us with more information on how Ford used the most unstable and heavy element in some magical light (or strong) alloy?
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4th of July
After seeing this at the 4th of July celebrations, I shudder to think what will happen if we started using Windows!
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Re:Backward Compatability
I am the president of a Linux Users Group and I maintain the website we have. LUGSB The site is fully XHTML1.1 and CSS2 compliant. (There are links at the bottom of the page that will validate it) For the most part support is very good. All of the layout is done with CSS. (there isn't one table on the site) A lot of it even works with NN4. But, the beauty with CSS layout and semantically correct XHTML is that it degrades really nicely. So, if someone hits my site with lynx it still renders in a very readable way with important links at the top and the data presented nicely. Try reading slashdot with lynx and having to wade through all the links that normally show up on the left side bar before you get to the articles. How annoying is that?
We also serve the pages as application/xhtml+xml to mozilla and other gecko based browsers. If you send that to IE it won't work. I think it just prints out the XHTML instead of rendering it. But, if you send the same data as text/html it works fine. If only IE would support transparent PNG images.
I think the best bet is drop support for Netscape 4.x. When I say drop support, I mean, make sure that the content of the site is still accessible even if NN4 users lose a little bit of the layout, it pays off with the benefits of CSS and XHTML.
Just my 2 cents.
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Re:The future is bit granular.
you might be thinking along the lines of the connection machine?
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A Real Nostradamus
1. It must be data oriented with no concept of instructions (just routing information), data flows in the system and transformed in a non-linear way, and the output will be all possible computations doable by the transformations.
So, what would these transformations be other than... instructions? You could show me a list of "transformations" that the input data is to undergo to generate an output, and I'd show you a list of "instructions" that tell the computer what to do to the input data to generate an output.
Furthermore, what you want is impossible-- "all possible combinations doable by the [yet uncounted] transformations." That's an arbitrarily large amount of work that requires an arbitrarily large machine and time to accomplish it.
2. It must be based on a fully interconnected grid of very simple processing elements.
Kinda like a Connection Machine, huh? Those are real new.
3. The performance of said computer will be measured in terms of bandwidth not the usual MIPS. As you can see you will need a classical type computer to operate the described computer above so it will not totally replace it.
Hrm. I suppose you've never noticed that memory buses are now specified by what amounts to a bandwidth number, as are IDE (ATA) bus family members. As to the "classical type" computer, again your prototype is the Connection Machine, circa 1983. -
Re:It's not dead
For those with ??? floating abover their heads...
Dead Parrot Sketch -
Time for a new "Matrix" iconHere are a few starting points for something other than the current use of Alka-Seltzer Cold Plus caplets:
Not sure what this is about...topless women in leather pants. (SFW)
What's cooler than a Toyota Matrix, all decked out in racing stickers?
Oh yeah, baby...Matrix, the board game
How about the Matrix folding bike? Before or after
The Vic-20 fans out there might appreciate a look at the Matrix game for that platform.
Flashback to math class! Matrix multiplication!
So you see, taco, you're only limited by your imagination. Of course, that could be like saying your writing is limited by your spelling and grammar but still...maybe someone can help you come up with something better. -
Algorithm Repository
What of Algorithm repositories like this one? This is probably a more useful resource as it emphasizes more on the algorithm itself and allows you to see the algorithm implemented in various languages.
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Re:Older kids learn Python easily enough
Very young kids have problems with attention span, reading, typing, etc. so you may want to use something like Lego Mindstorms instead of text-based programming.
Actually it's not just kids how have attention span issues who can benefit from Lego Mindstorms. If your siblings haven't yet taken high school geometry yet (or haven't had enough exposure to boolean logic), then Lego Mindstorms is a really cool to get a day-to-week-long introduction. Past that, I'd say, based on my own experience, that (when I was 11) C was difficult for me to pick up until after I learned Pascal. They both have similar structures, but Pascal was a much better introduction because of its use of natural language in most of its syntax.
You can find some tutorials here, here, here, here, and here.
The only problem with Pascal (nowadays) is that compilers/debuggers seem hard to come by. Here's a free one that might help. If that doesn't work, then you could always try something this, but I wouldn't recommend it for the beginner who doesn't even know what compilers or linkers are and why they are necessary. -
SAMSON
Check out the SAMSON project. They try to do stuff with "memory servers" that lets one computer access the RAM of another through a network.
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All I need
As a compiler researcher, lp_solve is all I need.
s bbminPERLth\nb.s xmix\u$&x.s dMidMad.s yPERLyjunay.print -
Re:A place to share code and algorithmic knowledge
a) There Exists the MIT text book which is excellent and full of algorithms, it is taught to most CS majors in algorithm class. "Introduction to Algorithms" by Carmen et. all. It has been posted in at least 4 other posted in the discussion, including one with a direct link to amazon.com...a recommend the second edition though
B) Another GREAT book is called "The Algorithm Design Manual" by Steven S. Skiena. It focuses more on the algorithms than a mathematical analysis of them. It teaches you how to model problems. The second part of the book is just a catalogue of algorithms. The revevant part to your discussion is here . It is the algorithm repository. It contains many implementations of algorithms in each langauge. Some implementations have weird licenses but aside from that it is a great site. -
You gotta love it...I just downloaded the [5] Warren Siegel, Fields book...
I have to admit I take a certain joy in seeing that a whole book on fields is a mere 3 Meg download.
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Where's "The C Programming Language" by K&R?"Anything with Knuth's name on it" includes a bunch of theist judeochristian superstition as well as some useless stuff.
In addition to Kernigan & Ritchie's 2nd edition, The C Programming Lanugage with ANSI C, which should be on any programmer's workbench, be they Perl, Matlab, Maple, TCL, or even elisp programmers, here are some others:
The Algorithm Design Manual by Steve Skiena. Excellent.
The Nuts and Bolts of Proofs -- the heart of correct math is showing your work, and this book shows you how.
The Data Game -- Controverses in Social Science Statistics -- this really puts you in touch with the kinds of numbers you hear bandied about on the news, and what those numbers mean.
The Maple V Learning Guide -- this comes with Maple (and presumably Matlab if you get it with Maple) and teaches more than a typical undergraduate mathematics program in about 270 pages. Actually, you have to delve into the hypertext documentation of Maple to get at all the calculus, linear algebra, statistics, etc., but it's all in there.
Studies in Inductive Logic and Probability -- actually there were two volumes published in 1980, and one or both might have gone out of print.
What If there were No Significance Tests -- this overpriced volume (which you should be able to get for much less from the publisher's site, www.erlbaum.com that doesn't seem to be working right now) explains exactly what soft scientists (e.g., psychologists) mean when they say something is true.
100 Statistical Tests -- this reasonably priced but somewhat advanced, applied book will tell you how to tell whether something is true, even if you have to use indirect or partially correlated measurements. The author has provided tools with what you can quickly find the appropriate test(s) for most situations I can imagine.
All I Ever Needed to Know I Learned From My Golf-Playing Cats. Here's hoping for the +1 Funny moderation for Ruben Bolling, whom I believe to be perhaps the finest editorial cartoonist, up there with Ted Rall, Tom Tomorrow, Tom Toles, and Gary Treadeau. Fantastic!
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From The Stony Brook Algorithm RepositorySee the Job Scheduling Algorithms from The Stony Brook Algorithm Repository, an excert of which follows:
"Devising a proper schedule to satisfy a set of constraints is fundamental to many applications. A critical aspect of any parallel processing system is the algorithm mapping tasks to processors. Poor scheduling can leave most of the expensive machine sitting idle while one bottleneck task is performed. Assigning people to jobs, meetings to rooms, or courses to final exam periods are all different examples of scheduling problems.
"Scheduling problems differ widely in the nature of the constraints that must be satisfied and the type of schedule desired. For this reason, several other catalog problems have a direct application to various kinds of scheduling.
"We focus on precedence-constrained scheduling problems for directed acyclic graphs. These problems are often called PERT/CPM, for Program Evaluation and Review Technique/Critical Path Method. Suppose you have broken a big job into a large number of smaller tasks. For each task you know how long it should take (or perhaps an upper bound on how long it might take). Further, for each pair of tasks you know whether it is essential that one task be performed before another. The fewer constraints we have to enforce, the better our schedule can be. These constraints must define a directed acyclic graph, acyclic because a cycle in the precedence constraints represents a Catch-22 situation that can never be resolved.
"The best book available for this problem is Intelligent Scheduling by Mark Fox."
Click here for the algorithms.
Disclaimer: I haven't used them.
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From The Stony Brook Algorithm RepositorySee the Job Scheduling Algorithms from The Stony Brook Algorithm Repository, an excert of which follows:
"Devising a proper schedule to satisfy a set of constraints is fundamental to many applications. A critical aspect of any parallel processing system is the algorithm mapping tasks to processors. Poor scheduling can leave most of the expensive machine sitting idle while one bottleneck task is performed. Assigning people to jobs, meetings to rooms, or courses to final exam periods are all different examples of scheduling problems.
"Scheduling problems differ widely in the nature of the constraints that must be satisfied and the type of schedule desired. For this reason, several other catalog problems have a direct application to various kinds of scheduling.
"We focus on precedence-constrained scheduling problems for directed acyclic graphs. These problems are often called PERT/CPM, for Program Evaluation and Review Technique/Critical Path Method. Suppose you have broken a big job into a large number of smaller tasks. For each task you know how long it should take (or perhaps an upper bound on how long it might take). Further, for each pair of tasks you know whether it is essential that one task be performed before another. The fewer constraints we have to enforce, the better our schedule can be. These constraints must define a directed acyclic graph, acyclic because a cycle in the precedence constraints represents a Catch-22 situation that can never be resolved.
"The best book available for this problem is Intelligent Scheduling by Mark Fox."
Click here for the algorithms.
Disclaimer: I haven't used them.
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From The Stony Brook Algorithm RepositorySee the Job Scheduling Algorithms from The Stony Brook Algorithm Repository, an excert of which follows:
"Devising a proper schedule to satisfy a set of constraints is fundamental to many applications. A critical aspect of any parallel processing system is the algorithm mapping tasks to processors. Poor scheduling can leave most of the expensive machine sitting idle while one bottleneck task is performed. Assigning people to jobs, meetings to rooms, or courses to final exam periods are all different examples of scheduling problems.
"Scheduling problems differ widely in the nature of the constraints that must be satisfied and the type of schedule desired. For this reason, several other catalog problems have a direct application to various kinds of scheduling.
"We focus on precedence-constrained scheduling problems for directed acyclic graphs. These problems are often called PERT/CPM, for Program Evaluation and Review Technique/Critical Path Method. Suppose you have broken a big job into a large number of smaller tasks. For each task you know how long it should take (or perhaps an upper bound on how long it might take). Further, for each pair of tasks you know whether it is essential that one task be performed before another. The fewer constraints we have to enforce, the better our schedule can be. These constraints must define a directed acyclic graph, acyclic because a cycle in the precedence constraints represents a Catch-22 situation that can never be resolved.
"The best book available for this problem is Intelligent Scheduling by Mark Fox."
Click here for the algorithms.
Disclaimer: I haven't used them.
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Meh
Not really that much of a spread of technologies, mostly just small-scale molecular/DNA computing and quantum computing. If you ask me the real front runners for next gen computing are RSFQ, spintronics, and massively parallel "quasi-processors" / reconfigurable computers (such as RAW and "smart memory"). More the kind of thing you'll see on your desktop 5-10 years from now rather than in the lab and still needing another decade to fully develop.
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Babbage did not invent the computerWIAKywbfatw wrote:
Oh, and by the way, the code breakers at Bletchley Park didn't invent the computer - Charles Babbage did that a great many years earlier.
No, the computer was invented long before Babbage. We know from the Ankythera Mechanism that at least one computer existed circa 87 BC. There is historical evidence to suggest that other, more complicated mechanical computers were built by the ancients; but the Ankythera device is the oldest extant machine. You can't play Quake on it, but it's still a computer. -
post-human?
post-human? I paraphrase Richard Leakey, who once stated at a lecture at Stony Brook, that he spent many years looking at the fossil record, trying to answer the question "When did we first break off from the rest of the primates and become human?". He's now convinced this has not yet occurred.
post-"Homo sapien" is more accurate. Genes make a species; they don't make a human being. Maybe we should focus on what it really means to be human rather than focusing on what happens next. -
tit for tatIn the eighties a guy named Robert Axelrod ran a tournament. Participants submitted computer programs, that were to interact with one another. The "society" they simulated was very simple. They could use any strategy to play the "prisoner's dilemma".
The program that ended up as the most successful was also the simplest. University of Toronto Game Theorist Anatol Rappaport had submitted a program he called tit for tat. Tit for tat initially cooperated with all the other players. In subsequent turns if the other player it was interacting with had defected last turn, it defected this turn. If the other player had cooperated last turn it cooperated this turn.
Yes, the interactions between people are very complicated, and this game is very simple. Still food for thought though.
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Re:Disney still doesn't "get it"
I agree. I am squirming in my seat waiting for Laputa (a decent fan's page here) to get wide release in the US. Apparently, Disney was going to release it in 1999, then in 2000, now I have no idea if/when they will do it.
They do also have to deal with the small problem that "laputa" is a very obscene word in Spanish, hence them just calling it "Castle in the Sky".
I also read that they re-did the music for the American version, because the original Japanese version only had about 1 hour of music in the 2-hour movie, but they feel American audiences can't go more than a few minutes without hearing music in a movie. They were saying how e.g. when an army appears, you have to hear army music, etc. Yeah, makes Americans sound like real idiots. (Ok, you know you wanna respond to that last bit.) The music in the original version is great; it's one of only two anime soundtracks that I just had to buy (the other was Windaria). -
Is this stuff really new?
This stuff is being reported as a very novel stuff. But there has significant research being done in academia.
Stony Brook (SUNY) ECSL has developed a Videoserver prototype. The difference between this technology and that of ECSL's is that, ECSL videoserver uses closed captions available in the news clips. This way the burden of speech recongnition is taken off the archiving and indexing servers.
You can read all about it at this page
This was developed in 1999. This is a well documented project and publicly available. During its initial days it was made available at several download sites. This is still available (documentation + sources) from ecsl website. The only problem is that, this was developed on redhat 5.2 version and used many Beta Stage libraries of gtk(--) etc. Which are now obsolete. It will take a little bit of effort to get it working on latest platforms.
-- Srikant -
Is this stuff really new?
This stuff is being reported as a very novel stuff. But there has significant research being done in academia.
Stony Brook (SUNY) ECSL has developed a Videoserver prototype. The difference between this technology and that of ECSL's is that, ECSL videoserver uses closed captions available in the news clips. This way the burden of speech recongnition is taken off the archiving and indexing servers.
You can read all about it at this page
This was developed in 1999. This is a well documented project and publicly available. During its initial days it was made available at several download sites. This is still available (documentation + sources) from ecsl website. The only problem is that, this was developed on redhat 5.2 version and used many Beta Stage libraries of gtk(--) etc. Which are now obsolete. It will take a little bit of effort to get it working on latest platforms.
-- Srikant -
The Stony Brook Algorithm Repository
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Re:Impractical circuits
Unfortunately,( RSFQ (Rapid Single Flux Quantum) circuitry is beyond the scope of SPICE simulations, but this appears to me to be a natural fit to the trinary logic paradigm.
Some circuits have already been physically built and tested - and at least one person feels that they lend themselves to tristate logic gates .
The basic principles are already in the category of proven technology - ever heard of a SQUID sensor?
Josephson junctions work equally well for either positive or negative currents - and so do magnetic flux quanta. (But this circuitry has to be the ultimate in low-power computing - you can't get much lower discrete amounts of energy than a single quantum of magnetic flux.) -
Re:Why Tri why not just go Analog ?
I dissected their inverter circuit in a different post -- in short, it won't work for the intermediate level, and in fact closely resembles a primitive ancestor of TTL binary.
Their inverter seems more related to current tristate outputs (i.e. zero, one, off) than trinary, but you might want to check the RSFQ tristate logic. Seems the links for more info are down at the moment, though. -
Re:Show me a trinary Schottky
The big disadvantage of using any logic system with more than two states, electrically, is that sometimes in switching from one state to another you must go through a third state which is electrically "valid" but not the correct output for the function you're implementing.
True, but that's what clocks or asynchronous handshakes are for - because even with only two levels, there's a lot of 'Wrong' state in between.
Admittedly, it might not be possible to define a 'gray code' signalling scheme using trinary digits, but a trinary clock signal ( -1, 0, +1, 0, -1) etc, could have definite benefits - quad speed data rate, data in trits would be effectively a 6X interface...
Electrically, implementation is inevitably binary, at its core... electrical comparisons of boundary conditions. "Trinary" is just a minimal case of "analog", with all of the same disadvantages.
Say what?? Where'd this come from? Binary itself is still a minimal case of analog - just with a single breakpoint instead of two with trinary.
You want the same noise margins? You'll have to double your voltage. That means you're cutting your speed in half. So overall you're taking a loss because at half speed you could have gotten two whole bits for your money instead of one lousey trit.
This depends very much on the implementation, but it is NOT necessarily cutting the speed in half. Assuming that the circuit has normal RC timeconstants, double the swing is NOT double the lag. (It's about 1.4 times the lag) This might not be significant in clocked ciruits, and at worst, the loss is about equal to the gain achieved by trits over bits.
Not to mention the fact that you're using more power, switching between these trinary states due to the longer transition and detection times.
Here you may be partly correct.
Assuming that there is a separate power supply connection for each signal state, the leakage in the drive transistors is probably going to be about double that of a normal binary output. The active power using a positive-zero-negative type signalling scheme should work out similar, since the voltage relative to ground won't be increased. The dynamic power would probably be comparable despite the larger swing since only 1/3 of the transitions involve the full possible swing while carrying 50% more information. And as I noted in the previous point, the transition (and detection) times are also comparable on a 'amount of data transferred' basis.
Oh boy! Hotter chips! Bleah!
All things considered, it looks like the heat to computing power ratio is going to similar for both. But if there truly are algorithms or applications that are more easily rendered using trits (and there may well be so) then the advantage for them may go to the trinary logic.
There may also be some uses for trinary base computing where the storage of additional logic states is NOT an overhead. Quantum flux gates - which unfortunately can't amplify or fan out yet - can store digits as fluz quanta - gates can be designed such that there is no overhead to such a device holding 2 quanta instead of one - and these chips will definitely NOT run hot. (Of course, cooling to superconducting temperatures may have its own problems.... for those interested, this is a link to the RSFQ lab pages, and a link to an item on superconducting trinary circuits. 100+GHz on 3.5um technology.) -
Re:Show me a trinary Schottky
The big disadvantage of using any logic system with more than two states, electrically, is that sometimes in switching from one state to another you must go through a third state which is electrically "valid" but not the correct output for the function you're implementing.
True, but that's what clocks or asynchronous handshakes are for - because even with only two levels, there's a lot of 'Wrong' state in between.
Admittedly, it might not be possible to define a 'gray code' signalling scheme using trinary digits, but a trinary clock signal ( -1, 0, +1, 0, -1) etc, could have definite benefits - quad speed data rate, data in trits would be effectively a 6X interface...
Electrically, implementation is inevitably binary, at its core... electrical comparisons of boundary conditions. "Trinary" is just a minimal case of "analog", with all of the same disadvantages.
Say what?? Where'd this come from? Binary itself is still a minimal case of analog - just with a single breakpoint instead of two with trinary.
You want the same noise margins? You'll have to double your voltage. That means you're cutting your speed in half. So overall you're taking a loss because at half speed you could have gotten two whole bits for your money instead of one lousey trit.
This depends very much on the implementation, but it is NOT necessarily cutting the speed in half. Assuming that the circuit has normal RC timeconstants, double the swing is NOT double the lag. (It's about 1.4 times the lag) This might not be significant in clocked ciruits, and at worst, the loss is about equal to the gain achieved by trits over bits.
Not to mention the fact that you're using more power, switching between these trinary states due to the longer transition and detection times.
Here you may be partly correct.
Assuming that there is a separate power supply connection for each signal state, the leakage in the drive transistors is probably going to be about double that of a normal binary output. The active power using a positive-zero-negative type signalling scheme should work out similar, since the voltage relative to ground won't be increased. The dynamic power would probably be comparable despite the larger swing since only 1/3 of the transitions involve the full possible swing while carrying 50% more information. And as I noted in the previous point, the transition (and detection) times are also comparable on a 'amount of data transferred' basis.
Oh boy! Hotter chips! Bleah!
All things considered, it looks like the heat to computing power ratio is going to similar for both. But if there truly are algorithms or applications that are more easily rendered using trits (and there may well be so) then the advantage for them may go to the trinary logic.
There may also be some uses for trinary base computing where the storage of additional logic states is NOT an overhead. Quantum flux gates - which unfortunately can't amplify or fan out yet - can store digits as fluz quanta - gates can be designed such that there is no overhead to such a device holding 2 quanta instead of one - and these chips will definitely NOT run hot. (Of course, cooling to superconducting temperatures may have its own problems.... for those interested, this is a link to the RSFQ lab pages, and a link to an item on superconducting trinary circuits. 100+GHz on 3.5um technology.) -
We're not running out of oil
Although many researchers have insisted that we will run out of petroleum by the year 2050 (or earlier), their calculations are fueled by coarse-grained extrapolation and bad science run amok. What many environmentalists do to advance their anti-oil cause is extrapolate oil use increases on 25-year or 50-year periods. For instance, they will find that oil use has increased (say) 250% from 1950 through 2000. And conclude that use will increase another 250% between 2000 and 2050.
Obviously that is not the case. The usage increases were huge when the nation became industrialized and started needing more energy, but it is ludicrous to think that the rate of change will remain constant. That is like saying that since the number of homes with PCs has increased by 1500% since 1985, it will increase another 1500% by 2017.
-all dead homiez -
Re:Just another reason to be SSH tunneling
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Re:Required Key Escrow As Law Enforcement Tool
Just ask the Brits about the utility of this kind of law. After all, over there if the police demand you release your crypto keys, you're not allowed to say that you don't have them.
The example that someone actually implemented was to write a confession to a crime, encrypt it with a PGP key that claimed to belong to the Minister backing the stupid law. Then they destroyed the keys.
My biggest beef with Key Escrow or compulsory back-doors is as discussed in Cryptography, Privacy and Crypto-Anarchism.
In addition, this stupid kind of law adds more burden to foreign nationals. Say I use strong crypto to post a message to a discussion group. Say that discussion group is hosted in the good old USA. If I ever take a trip to the USA - or even just stop over in Hawaii en-route somewhere else - I'll get arrested by US forces for breach of US laws, a la Dimitri Sklyarov.
The minor benefit gained by this kind of policy is totally undermined by the amount of evil that can be performed. Imagine for a second that bureaucrats weren't paid enough to do their jobs. Imagine for a moment that some bureaucrats weren't the exemplars of moral integrity that they are. Just say it was possible for a large corporation, intent on stealing some other companies ideas, to bribe a bureaucrat to hand over (sorry, accidentally leave untended) the escrow keys for a competitor (or competitors). Is that the kind of world you want to live in?
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diode laser drivers
I see new devices with more easily controlled parasitic capacitance and inductance because of the dimensions of carbon nanotubes. This will be good for high frequency, high power applications as well as logic circuitry. Carbon nanotubes "want" to be certain sizes depending on the number of carbon atoms in a ring of the tube and the presence of dopants like boron or potassium. These things might make good diode laser drivers. Focused arrays of laser diodes could be an interesting way to nano-manipulate colloidal materials or proteins. Follow the links from here on Optical Tweezers.
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Not SO inaccurate.The nanotechnology in question is the production of nanoscale materials. But it can also refer to the thermal spray process which is used to form the nanoscale materials.
As far as hardness and strength. They harder a material is the stronger it is. The actual relation isn't trivial to derive and depends on things like the tip you use for intentation, qualitatively, it isn't that difficult to grasp so I'll do my best to explain. Strength is the ability of a material to resist plastic deformation. Plastic deformation is when you stretch a material and it won't snap back, as opposed to elastic deformation where it will. Try bending a paper clip, very little at first, it will snap back like you never touched it. Now bend it around. Where you bent it, the bumps and twists, are now harder and resist bending more than the rest of the paper clip and make it look irregular. That's plasitically deformed. It won't ever be like it was unless you remake the paper clip. If you bend it a little more it should get a little bit harder, then stiff and easy to break. That's a qualitative stress-strain curve you can feel. Then same thing happens when you push an indentor into a material, some of it gets pushed out of the way to make room for the indentor, which isn't all that different from bending the paper clip. In fact hardness is so closely related to the strength of a material you can do a surface hardness test to find out what alloy something is made of without destroying it. One of those things. On the other hand, this is a coating, so it's always on the surface of something, and in that sence you're right. Hard coatings typically need less lubrication, experience less fretting (a form of mechanical corrosion), etc. They also mention that it has self-sharpening characteristics. So it might find its way into new anti-armor weapons, or just the sharper image catalog.
Yeah I would say this is front page stuff. Getting a metal to come near the theoretical ideal in strength is pretty impressive. This is at least as front page as anything else up there. A good overview of thermal spray can be found here.
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Re:Technic, anyone?My friend's son has a lego sports car, out of the "Technic" series of kits. This thing is actually quite impressive. Working shifting mechinism+gearbox (5 speeds plus reverse),
As some other poster noted, LEGO has the problem that with time it's moving toward the "few specialized pieces" approach instead of the "lots of unspecialized pieces". Technic is following the same trend: if you grab hold of the ORIGINAL technic boxes you'll see that they had very very few pieces, but they managed nevertheless to build objects of high complexity. I owned most of them as a kid (they still sit somewhere at my parent's), and in particular I remember the first "car" box, featuring 4-piston engine, gearbox (3 speeds, I think), steering wheel, adjustable seats, and all of this done with basically the classic lego pieces plus 20-30 parts (shafts, wheels,....).
What's more interesting is that with the same parts you could build anything else, since they were absolutely non-specialized, pushing creativity much more that the current sets.
See what I mean at this site.
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Re:Neutrino detector arrayI need some more convincing that neutrinos are changing on their way to Earth. A good way to give more credence to this idea would be to place both types of detectors at several points...
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nothing wrong with sml.
SML is pretty standard for intro CS classes.
It's part of one of the classes I'm taking right now, actually.
While I found it slightly confusing at first, coming from a background of C-like programming, I can see why it's a good choice. For a student with no programming experience, SML is very close to the mathematical recursion and discrete math. That way their mathematical knowledge can transfer over pretty easily.
It's also a nice way to learn functional programming.
---harlan -
Re:Leave Stalin alone ok?
Two words:
Victor Suvorov -
Re:pico-wires
This transistor technology (Single Electron Transistors) cannot be used to make large circuits, because it is extremely sensitive to spurious charges in its surroundings. It does have its special uses, though, e.g. ultra-precise current measurements, standards calibration, and that sort of thing.
What is more interesting is that this type of controlled manufacturing of quantum dots opens up the possibility of making quantum computers.
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Re:Automotive Industry
I don't know if this is an urban legend or not, but I had heard that petroleum is actually more valuable as a lubricant than as a fuel, because we can't yet create synthetic lubricants which are as good as the real thing. The danger is that all of our machines may literally grind to a halt when we run out of oil, even if the machines themselves are solar/nuclear/etc powered.
True and false. There ARE in fact things we can put together out of carbon which are superior to any petroleum-based lubricant. Unfortunately, no one has done so commercially. This is mostly because it's expensive. You can see pictures of buckyballs here. CMU has a buckyball project. So does SUNY. You could make your own fullerenes. There are a number of fullerene-related patents.
That last page produces the real gem: this patent is for a "Magnetic recording medium comprising a solid lubrication layer of fullerene carbon having an alkyl or allyl chain". The abstract reads:
A magnetic disk has a magnetic medium or a protection film, and a solid lubrication film formed on the medium or the protection film and consisting of a fullerene C60, C 70 or C84 and an alkyl or allyl-chained fullerene. The lubrication film provides the disk with high mechanical durability and high linear recording density.
There are further supporting references. The Buckyball: An Excruciatingly Researched Report (which gives its references at the bottom) contains this quote:
A fully fluorinated buckyball would create the slickest molecular lubricant known to man, C60F60. The uses for a molecular lubricant are boundless, limited only by our imagination.
Of course, I don't know that anyone's actually assembled such a molecule. I located an article called Just Rolling Along which discusses tungsten disulfide, which is similar to buckyballs. It is, however, expensive to produce, and difficult to make in quantity; This is what we're waiting for. Incidentally, I did find one article that gave hope for this, under the heading "Cheap Buckyballs". Amusingly enough (to me) the anchor tag is named "cheapballs". I guess when you're hopped up on this much sugar all kinds of things are funny. If anyone has access to the text of "Journal of Organic Chemistry, March 8" perhaps they could help out here.
So in summary, there ARE better lubricants than those cracked from crude. They are not, however, currently on the market, as they are expensive and time-consuming to produce. However, science marches on, and we'll solve this problem, too.
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Re:Automotive Industry
I don't know if this is an urban legend or not, but I had heard that petroleum is actually more valuable as a lubricant than as a fuel, because we can't yet create synthetic lubricants which are as good as the real thing. The danger is that all of our machines may literally grind to a halt when we run out of oil, even if the machines themselves are solar/nuclear/etc powered.
True and false. There ARE in fact things we can put together out of carbon which are superior to any petroleum-based lubricant. Unfortunately, no one has done so commercially. This is mostly because it's expensive. You can see pictures of buckyballs here. CMU has a buckyball project. So does SUNY. You could make your own fullerenes. There are a number of fullerene-related patents.
That last page produces the real gem: this patent is for a "Magnetic recording medium comprising a solid lubrication layer of fullerene carbon having an alkyl or allyl chain". The abstract reads:
A magnetic disk has a magnetic medium or a protection film, and a solid lubrication film formed on the medium or the protection film and consisting of a fullerene C60, C 70 or C84 and an alkyl or allyl-chained fullerene. The lubrication film provides the disk with high mechanical durability and high linear recording density.
There are further supporting references. The Buckyball: An Excruciatingly Researched Report (which gives its references at the bottom) contains this quote:
A fully fluorinated buckyball would create the slickest molecular lubricant known to man, C60F60. The uses for a molecular lubricant are boundless, limited only by our imagination.
Of course, I don't know that anyone's actually assembled such a molecule. I located an article called Just Rolling Along which discusses tungsten disulfide, which is similar to buckyballs. It is, however, expensive to produce, and difficult to make in quantity; This is what we're waiting for. Incidentally, I did find one article that gave hope for this, under the heading "Cheap Buckyballs". Amusingly enough (to me) the anchor tag is named "cheapballs". I guess when you're hopped up on this much sugar all kinds of things are funny. If anyone has access to the text of "Journal of Organic Chemistry, March 8" perhaps they could help out here.
So in summary, there ARE better lubricants than those cracked from crude. They are not, however, currently on the market, as they are expensive and time-consuming to produce. However, science marches on, and we'll solve this problem, too.
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Re:InnovationIf current trends are projected forward, by 2020 a bit of memory will be a single electron transistor, traces will be one molecule wide, and the cost of the fabrication plant will be the GNP of the planet. The speed of light imposes practical limits on how large you can make a chip and how fast you can clock one. This is why we'll have GHz chips, but fundamental physical laws prevent THz chips.
The current speed record for a digital flip-flop is 770GHz..
While this technique is nowhere close to go into mainstream (or even scientific) computing it still shows that circuits operating in close-to-one-THz range are possible. Things might be different in twenty years. And Prozessors in the THz range would for sure be nowhere close to the CPUs we have today. Probably heaviliy asynchronous processors using architectures like systolic arrays etc. have to be used.
Also dont forget that mainstream CPUs are not made with the fastest technology available, but with the cheapest. By the use of GaAs Cray was able to achieve clocking speeds of around 1GHz in a time when a stock PC was clocked at 33MHz - so what might a GaAs CPU with current technology scale up to today ? Or how about BiCMOS ? (given that you have a personal power plant and some insane cooling device
;) ) -
RSA encryption
One project that might be interesting for HS students would be RSA encryption. It's probably easier to implement in Maple than a low-level languate like C. At least that's what we learned it in this easy course I took, see project #2
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Re:i want to see those damn pictures!!!
My wife took some pics yesterday at the Macworld show. They are at http://superk.physics.sunysb
.edu/~yoko/Mac/World/thumb. -
Re:Interesting
I really don't care for their choices at all. A lot of them are more like general approaches than algorthms, and I'm not at all sure they are the most influential. I think they are supposed to be "the cleverest of the common fancy methods"
Simple algorithms for common problems are much more widely used, and have far more impact and influence, but try telling *them* that!
I hope these links help. (Warning: many are technical) If anyone has personal favorites that are less dry than many of these, please post!.
10. 1987: Fast Multipole Method. A breakthrough in dealing with the complexity of n-body calculations, applied in problems ranging from celestial mechanics to protein folding. [Overview] [A math/visual approach]
9. 1977: Integer Relation Detection. A fast method for spotting simple equations satisfied by collections of seemingly unrelated numbers. [Nice article with links]
8. 1965: Fast Fourier Transform. Perhaps the most ubiquitous algorithm in use today, it breaks down waveforms (like sound) into periodic components. Everyone knows this one (or should) [Part II of my personal favorite FFT and wavelet tutorial]
7. 1962: Quicksort Algorithms for Sorting. For the efficient handling of large databases. [Definition][Basic Method][Mathworld][More technical explanation][A lecture with animations and simulations]
6. 1959: QR Algorithm for Computing Eigenvalues. Another crucial matrix operation made swift and practical. [Math] [Algorithm
5. 1957: The Fortran Optimizing Compiler. Turns high-level code into efficient computer-readable code. (pretty much self-explanatory) [History and lots of info]
4. 1951: The Decompositional Approach to Matrix Computations. A suite of techniques for numerical linear algebra. [matrix decomposition theorem] [Strategies]
3. 1950: Krylov Subspace Iteration Method. A technique for rapidly solving the linear equations that abound in scientific computation. [History] [various Krylov subspace iterative methods]
2. 1947: Simplex Method for Linear Programming. An elegant solution to a common problem in planning and decision-making. [English} [Explanation with Java simulator] [An interactive teaching tool
1. 1946: The Metropolis Algorithm for Monte Carlo. Through the use of random processes, this algorithm offers an efficient way to stumble toward answers to problems that are too complicated to solve exactly. [English] [Code and Math] [Math explained] -
There are PCI regular modems.
Check out the PCI modems and linux page.
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PCI non-winmodems... THEY DO EXISTUntil recently I too thought all PCI modems were winmodems, but recently a few controller-based PCI modems have arrived. Finally!
The 3Com 5610 for example, has been verified to work in Linux.
A HOWTO for mapping PCI modems to the
/dev/modem port and a list of PCI non-winmodems can be found on the PCI modems and linux page. -
Re:I'm still waiting for one that can get me a pizMy advisor and I used genetic algorithms to do optimizations for an NP-complete problem which arises in building certain types of genetic sequencing "chips" (the paper is here (postscript). This is a practical application which seems much harder to me. Our optimizer ran on a *single* Sparcstation 5 in a matter of minutes.
The Intelligent Robotics Laboratory at Vanderbilt University (where I spent a summer) was doing things back in 1994 that were much more difficult to do than this project without having to resort to GA's (which are generally considered by real algorithmicists to be a last resort (it was in our paper cited above)). And neither of these were the "cutting edge" environments you get at places like CalTech, MIT, or some industrial labs.
And, I wish I could give you a link (but I can't remember the fellow's name) to the research (which may have appeared on Slashdot) being done in simulating evolution in physical environments. The main researcher in question gave a seminar at my former employer (a company which does mathematical modelling of complex phenomena) a year and a half ago showing film clips of "evolved" computer "life forms" which solved physical motion problems in ways eerily similar to extant "real" creatures. Same lab (I've searched for 45 minutes now for a link or an old email about the presentation and am coming up dry so don't ask -- if I find it I'll post it) was doing visualizations of "evolved programs" where they were finding evolved (GA's) redundancies in coding operations similar to those found in actual natural DNA/RNA.
So using 1000 pentiums to make a lego bridge via GA's is newsworthy? Bah! Gimme a break.