U of I also came out with a genius plan to 'lock in' your rate for 4 years, so if there is a short fall, the next year is going to have a huge jump in tuition.
This wasn't the U of I's idea. We have the great Governor Blago to thank for this. Not only did he decrease funding for the university, he also made it harder for the U to raise its own. Genius!
As someone else has already pointed out, there is a difference between a virus (smallpox) and a bacterium. But it's false to think that every virus on earth causes disease in humans: when was the last time you were sick with feline leukemia? Any new, random virus probably won't be dangerous to humans. Some of our most deadly diseases come from millennia of close contact with domesticate animals, something you probably aren't going to find on Mars.
Bacteria are the same way. There are probably over a million different species and yet only a small percentage of those cause disease in humans. In fact, some of them even help humans with tasks like digestion! The odds of a random bacteria on Mars being harmful is incredibly small. Hell, we might even find one that colonizes our mouthes and stops tooth decay.
I wouldn't worry about viruses and bacteria when deciding to teraform Mars.
The point is that we can see evidence that a climactic equilibrium that has existed for hundreds of years is now becoming much more dynamic and unpredictable. And we're probably to blame for at least some of it, and maybe most of it.
Hundreds of years on a geological time scale is nothing; it's a blink of an eye. And the climate hasn't been stable for even that long. On a scale of tens of thousands of years it's obvious that the planet has a cyclic climate, oscillating between ice ages and periods of warmer temperatures than we have now.
Yes, our greenhouse emissions have almost certainly sped up the warming that was happening anyways. Instead of tens of thousands of years we're now talking hundreds of years.
But the big question, in my mind, is "what comes next?" We weren't there to observe the previous cycles; sure, we know they happened but we don't completely understand why. Have we broken the cycle or just given it a little kick? Will current global warming lead to another mini-ice age?
I find the article interesting in relation to those questions. There's no point in worrying over it: how do you stop 70 billion tonnes of methane? You don't. If we have reached some sort of tipping point then hold on. Humans will either learn to adapt or we'll die. I happen to think we'll adapt just fine.
Except, you know, the Russian Buran Shuttle with 20 tons return capacity vs the shuttle's 15 - and 30 tons of launch cargo capacity vs the Shuttle's 25.
Not bad. Not bad at all.
Best of all, the Buran could fly to orbit and back on autopilot without a human crew if needed (as it successfully did on a test flight).
From the Wiki article, the final version of the Buran has a single, solitary flight and this flight was unmanned. Hardly an impressive record, no?
The best thing that NASA could have done at the time to replace their shuttle fleet would have been to fund or buy Buran from the Russians when they ran out of money. the Russians built an amazing robot spaceplane in the 80's, something that NASA still has not achieved.
Again, from the Wiki article: "The U.S shuttles landings are also mostly automated (there has only been one manually flown re-entry so far), but deployment of the landing gear requires a human to physically press the button. The manual step was added at the insistence of the astronauts, who claim that early deployment of the landing gear due to a computer error would be fatal." Geee... which flag are you waving?
NASA's shuttle is a bastard design created from political compromise: the military wanted it, the scientists wanted it, the politicians wanted it. As a result it works for almost nobody and is a 30-year old deathtrap. I'm suprised the loss rate has been so low - I have no idea what drugs NASA is ingesting, I'll be very suprised if this one isn't lost as well. The shuttle should be killed and replaced ASAP, preferably taking some serious clues from bulletproof no-compromise brute simplicity Russian space engineering - which is currently the best in the history of the world (until the Chinese or commercial sector catches up and passes them).
Reading this is funny (in a dark way) in light of a recent article over at MoFi concerning the R-16 accident. Possibly the worst rocket accident in history and it was caused by... political and symbolic concerns trumping scientific ability.
If the shuttle's re-entry angle is wrong, EVEN WITH NO DAMAGE, airframe stress becomes critical, it breaks up and everybody dies.
If a Russian space capsule's re-entry angle is wrong, they experience slightly higher G-forces and the pickup helicopter takes a couple of minutes longer to reach them after parachuting to earth.
You've switched gears and are comparing a shuttle to a capsule. What happens if a US capsule's angle is wrong? What happens if the Buran's angle is wrong?
Modern metal alloys are tough enough to survive re-entry without protection from heat tiles. Get that? In a modern design, NO HEAT TILES ARE NEEDED. Which completely eliminates the cause of one shuttle disaster (when the heat tiles failed).
I'm hardly an expert, but I thought the purpose of the tiles wasn't to simply survive heat but to prevent its conduction. Can you take a modern alloy of similar weight and thickness, heat one side with a torch and hold your hand on the other? Then you have a fair argument.
Ohh, I don't know... how about Amazon and Salon? Kuro5hin and all the other Scoop based sites like DailyKos and MyDD. And now that I think about it, MovableType, TypePad, and LiveJournal are all writen in Perl.
You are mistaken on some Apache concepts and how threads (?used to?) work on Linux.
This is because for each request, Windows must create a new process (the CGI program), and destroy the process when the request is complete.
While the execution time is low, the process management overhead dwarfs the actual page runtime, because Windows doesn't do that sort of thing quickly. This is why CGI has long been blacklistedon Windows systems by good web devs, and this is one reason that Apache 1.x was such a dog on Windows. Apache 1.x creates a new Apache process for each request.
No.
Now Linux, on the other hand, creates processes about as fast as it creates threads, which is to say, really damn fast.
Yes, but only because pthreads does this by creating a new process (that just happens to share some things with its parents, like address space). Ergo, creating threads is just as fast as creating processes because they are nearly the same thing.
The NPTL in 2.6 might have changed this, but I have not read the docs yet.
Yet Apache is still back here creating a process or thread for each and every request (note that there are some ways to speed things up. FastCGI comes to mind, but I don't want to get into the gory details that I don't know enough about). This is not the brightest way to do it in terms of performance, but then, Apache appears to have been designed for universality and configurability over raw throughput.
No, Apache does not create a new process for each request. It creates a pool of child processes which sit waiting for requests. The parent monitors this pool and creates new spare children when too many child processes are busy. This way, most of the time a request comes in there is already a child process sitting idle waiting for work.
CGI does indeed require forking a new process, but there are already great ways to handle this. mod_perl, mod_php, mod_python all do it by embeding the interpreter inside the server. FastCGI keeps a version of the program running (much like apache does with its spares).
You are correct in that your description isn't the brightest way to do things. That's why operating system designers solved these problems years ago.
For static content, again, Apache creates a new process or thread for every request (with some exceptions). If you'll forgive a bit of an oversimplification, it's like writing a program that prints text to the screen. One program calls printf() in a loop. The other program executes a second program which itself displays just one line, and runs that in a loop.
Again, no. Apache will usually not need to create a new process or thread for every connection. The correct analogy would be the other program spawning the required number of children, and then asking them to all printf at the same time.
His problem seems to be with the development process of Firefox itself, not with stuff that happening in the main Mozilla trunk. For example, the following projects he doesn't have problems with: XTF, SVG, XForms, E4X, and xulrunner (lifted from the comments).
What I gather this means is that Firefox 1.1 will get some cool new backend features but that its front end stuff will remain mostly the same (excepting the preferences dialog). Is this really a bad thing?
A caching system won't work for the same reason web caches have never caught on in the US - people are terrified of being sued to smithereens for potential copyright infringement. Even if any case would be thrown out of court instantly (by no means certain in the US) the costs would be prohibitive and malicious plaintifs rarely ever get asked to pay costs.
Maybe the caching is just so damn good that you don't notice it. UIUC has a transparent web cache that I doubt 90% (of ~8,000) of the dorm students realize is there.
Also, Akamai is everywhere now. Is it not a caching solution?
I don't think web caches have failed... I just don't think they've been applied to the RSS problem.
Please excuse the spelling. I'm tired, and it is past my bed time tonight.
A Faraday cage is a conductor, so charges are free to move inside.
Let's clarify this real quick: I assume you are talking about the inner and outer surfaces, not the volumes.
When the outside is exposed to a negative charge, all the electrons 'flee', and leave a positive charge on the surface. They 'flee' to the other side of the surface, to bunch up in negative charges: that is, inside the cage. Hence exposing the inner volume of the cage to negative charges, exactly at the level of incoming negative field to be exact.
(digging out my handy Elements of Engineering Electromagnetics, 5th Edition, Rao)
Right, this is a physical explaination of the boundary condition that says the discontinuity in the E field between the sides is equal to the amount of charge present on the conductor. However, you're forgetting to mention that our conductor in this case is a closed surface, and that surfaces are equipotential. Charges don't bunch up on one part of the inner surface, they distribute equally. And assuming the surface is closed, mathematics necessitates that all the internal E fields will cancel.
Otherwise, you would have an imbalence, and would create an E field in a region that does not contain any charge.
When the cage is grounded, 'fleeing' electrons are not accumulated on the other side of the surface, but rather are dissipated, leaving the inner surface of the cage perfectly neutral, and hence not exposed to electrical fields.
True, but unnecessary. The E fields are going to balance perfectly anyways, and cancel themselves out.
An example of this is Coax cables. Coaxial cables are basically a faraday cage made long. Coax cables are perfectly immune to interference *only* if the outter core is grounded. If it is not grounded, they are subject to any interference the whole system is subjected to.
Ummm... not really. Assume you have a positive current on the center wire. Using the right hand rule, this creates a positively charged, cirularly symetric E wave that radiates outwards (think throwing a rock in a pond). If you pass the negative equivalent of this signal on the outer shielding, you generate an opposing E field that will directly cancel the internal one. Again, you don't have to ground the external shielding.
Of course, this is all theoretical. As someone else mentioned, the electrons can only propagate so fast, and there will be some delay. But I believe it will work well enough. I'm not sure what frequency they use for these chips, but it can't be too high for something so simple.
A Faraday (one r) cage needs to be grounded or it won't work. A tin foil is sufficiently 'cage-like' (when it comes to passports), but it isn't grounded.
Huh? Correct me if I'm wrong, but according to my 4.5 years of EE, Faraday cages work on the principal of Gauss' Law. That is, no EM field can be present inside because there is no charge inside. Wikipedia seems to agree with me.
So where does all this discussion of grounding come in? Googling for Faraday cage brings up this detailed article about building one, but it doesn't mention grounding either.
This page mentions grounding, but only in relations to the instruments, not the table. And this humorous article says grounding is only required if you have to have edges on your cage (we could design passport books so the edges are metal contacts).
I'd be more concerned with whether tin foil is a sufficient conductor for the higher frequencies.
What I'm saying is that the vast majority of highly moderated posts seem to be discounting the research with pretty superficial arguments, and little authority.
That's possibly the best one line description of Slashdot I've ever seen.
Unlike Farscape, Babylon5 wasn't canceled. JMS planned for 5 seasons, and although it was rough at times, he got all of them. Everything was wrapped up; the show is done.
I do think there is a movie in the works, but they had better hurry up. The actors keep dying.
(yes, I love both B5 and Farscape... but probably B5 more)
OFDM(orthogonal frequency division multiplexing) is a spread-spectrum technique meaning it spreads its energy(the data) out over a wide range of carrier frequencies -- the total power output required is actually less than by using a single carrier.
It's even smarter than that! Your little rect in time domain is an inf. sinc in the frequency domain. Of course, after a certain length it dies down to a negligible strength (call this point B). If you wanted to modulate another pulse, to guarantee they will both be exactly recoverable you need to modulate the new pulse up to 2B.
OFDM basically take advantage of the fact that the signal is digital. Instead of modulating the next pulse at 2B, you modulate it so that the next pulse is centered over the first zero crossing of the first pulse. Normally, this would cause horrible aliasing, but since you know the shape of your input data, all you care about are the values at the origin and the zero crossing. You don't care about recovering the two original signals exactly, the value at the origin and the first zero crossing give you enough information to reconstruct them. Aliasing be damned!
This takes advantage of the fact that simpler data is more resistant to noise. If you know what you're sending is a 1 or 0, then the waveform can be horribly degraded before it makes a difference. Contrast this with simple voice data, where a deformation in the wave can't be repaired (you don't know what it should look like). In this case, your encoding scheme introduces noise it knows doesn't matter in order to save bandwidth.
Of course, this is also a form of quadrature multiplexing, which lets you send two signals at the same carrier frequency but differentiate them based on the phase. So that gives you twice the transfer amount you'd normally get above.
(yes, I'm in a communications theory course right now)
I would agree with the ban, if the students were connecting their access points to the universities network. But even the policy statement admits the access points "are connecting to Comcast Cable Modems or to SBC DSL (or other providers) for their Internet access and then are being shared out to other residents within the same or adjacent suites."
So students a paying for their own, non-university internet connection, and sharing it with their neighbors. Taking into account the FCC document, I don't think there is much the university can legally do.
The group I work for is ICS, and we run the largest system of general computing labs on campus. The latest batch of Dells didn't include floppies as part of the standard package and we would have had to pay extra for them. So we just left them out.
Also, for consistency, we've disabled the floppy drives in the other 300 Dells we have, and removed the external drives from all 70 iMacs. You can't sit down at any of our machines and use your floppies anymore.
Instead, we've been pushing technologies like CD-RW, Netfiles (campus wide network storage), and little USB drives. Any one of these media are more durable than floppies; I can't remember how many people over the years have come crying to me because they lost the only copy of their final paper. And there hasn't been any huge uproar over it either among the students or faculty (at least I gaven't noticed any multi-page DI exposes).
Although I'm more centrist than anything else, I understand your point. But I still don't see how the (now) grandparent comment is on topic for this/. discussion.
I thought political humor was supposed to be funny. Your link is just a rabid attack that although it has a few logical points mostly misrepresents the issues (when it isn't launching on an ad hominem attack that is).
The parent post is only tangentially on topic in the sense that it's about politics. This Land was funny because it poked at both candidates; the parent's link is just spiteful.
Very few people download movies to make a profit off of them. We download the movies because it is convienient to do so (ala iTunes).
I honestly think some people -- maybe not the majority but a significant minority -- download movies, songs, TV shows, software, etc because they are addicted.
I'm willing to bet that everyone here knows at least one guy (or girl) who has hundreds of thousands of MP3s, some of which they've only listened to once. Or maybe someone who has dozens of complete TV series. You walk into these people's rooms and there are tons of 100 disc CD spindles sitting on shelves, completely burned and just collecting dust.
I have to believe in these cases that it's a form of internet cleptomania. Not the most damaging of disorders, but still not fucking right.
Slashdot Mirror
If you've ever used VMware Server 2 you wouldn't be eager for their pure HTML interface. At least the flash one works...
If you have an HBO subscription then I why aren't you using hbogo.com to watch the episode you missed?
U of I also came out with a genius plan to 'lock in' your rate for 4 years, so if there is a short fall, the next year is going to have a huge jump in tuition. This wasn't the U of I's idea. We have the great Governor Blago to thank for this. Not only did he decrease funding for the university, he also made it harder for the U to raise its own. Genius!
As someone else has already pointed out, there is a difference between a virus (smallpox) and a bacterium. But it's false to think that every virus on earth causes disease in humans: when was the last time you were sick with feline leukemia? Any new, random virus probably won't be dangerous to humans. Some of our most deadly diseases come from millennia of close contact with domesticate animals, something you probably aren't going to find on Mars.
Bacteria are the same way. There are probably over a million different species and yet only a small percentage of those cause disease in humans. In fact, some of them even help humans with tasks like digestion! The odds of a random bacteria on Mars being harmful is incredibly small. Hell, we might even find one that colonizes our mouthes and stops tooth decay.
I wouldn't worry about viruses and bacteria when deciding to teraform Mars.
The point is that we can see evidence that a climactic equilibrium that has existed for hundreds of years is now becoming much more dynamic and unpredictable. And we're probably to blame for at least some of it, and maybe most of it.
Hundreds of years on a geological time scale is nothing; it's a blink of an eye. And the climate hasn't been stable for even that long. On a scale of tens of thousands of years it's obvious that the planet has a cyclic climate, oscillating between ice ages and periods of warmer temperatures than we have now.
Yes, our greenhouse emissions have almost certainly sped up the warming that was happening anyways. Instead of tens of thousands of years we're now talking hundreds of years.
But the big question, in my mind, is "what comes next?" We weren't there to observe the previous cycles; sure, we know they happened but we don't completely understand why. Have we broken the cycle or just given it a little kick? Will current global warming lead to another mini-ice age?
I find the article interesting in relation to those questions. There's no point in worrying over it: how do you stop 70 billion tonnes of methane? You don't. If we have reached some sort of tipping point then hold on. Humans will either learn to adapt or we'll die. I happen to think we'll adapt just fine.
Except, you know, the Russian Buran Shuttle with 20 tons return capacity vs the shuttle's 15 - and 30 tons of launch cargo capacity vs the Shuttle's 25.
Not bad. Not bad at all.
Best of all, the Buran could fly to orbit and back on autopilot without a human crew if needed (as it successfully did on a test flight).
From the Wiki article, the final version of the Buran has a single, solitary flight and this flight was unmanned. Hardly an impressive record, no?
The best thing that NASA could have done at the time to replace their shuttle fleet would have been to fund or buy Buran from the Russians when they ran out of money. the Russians built an amazing robot spaceplane in the 80's, something that NASA still has not achieved.
Again, from the Wiki article: "The U.S shuttles landings are also mostly automated (there has only been one manually flown re-entry so far), but deployment of the landing gear requires a human to physically press the button. The manual step was added at the insistence of the astronauts, who claim that early deployment of the landing gear due to a computer error would be fatal." Geee... which flag are you waving?
NASA's shuttle is a bastard design created from political compromise: the military wanted it, the scientists wanted it, the politicians wanted it. As a result it works for almost nobody and is a 30-year old deathtrap. I'm suprised the loss rate has been so low - I have no idea what drugs NASA is ingesting, I'll be very suprised if this one isn't lost as well. The shuttle should be killed and replaced ASAP, preferably taking some serious clues from bulletproof no-compromise brute simplicity Russian space engineering - which is currently the best in the history of the world (until the Chinese or commercial sector catches up and passes them).
Reading this is funny (in a dark way) in light of a recent article over at MoFi concerning the R-16 accident. Possibly the worst rocket accident in history and it was caused by... political and symbolic concerns trumping scientific ability.
If the shuttle's re-entry angle is wrong, EVEN WITH NO DAMAGE, airframe stress becomes critical, it breaks up and everybody dies.
If a Russian space capsule's re-entry angle is wrong, they experience slightly higher G-forces and the pickup helicopter takes a couple of minutes longer to reach them after parachuting to earth.
You've switched gears and are comparing a shuttle to a capsule. What happens if a US capsule's angle is wrong? What happens if the Buran's angle is wrong?
Modern metal alloys are tough enough to survive re-entry without protection from heat tiles. Get that? In a modern design, NO HEAT TILES ARE NEEDED. Which completely eliminates the cause of one shuttle disaster (when the heat tiles failed).
I'm hardly an expert, but I thought the purpose of the tiles wasn't to simply survive heat but to prevent its conduction. Can you take a modern alloy of similar weight and thickness, heat one side with a torch and hold your hand on the other? Then you have a fair argument.
Who still uses Perl for web stuff?
Ohh, I don't know... how about Amazon and Salon? Kuro5hin and all the other Scoop based sites like DailyKos and MyDD. And now that I think about it, MovableType, TypePad, and LiveJournal are all writen in Perl.
You are mistaken on some Apache concepts and how threads (?used to?) work on Linux.
This is because for each request, Windows must create a new process (the CGI program), and destroy the process when the request is complete. While the execution time is low, the process management overhead dwarfs the actual page runtime, because Windows doesn't do that sort of thing quickly. This is why CGI has long been blacklistedon Windows systems by good web devs, and this is one reason that Apache 1.x was such a dog on Windows. Apache 1.x creates a new Apache process for each request.
No.
Now Linux, on the other hand, creates processes about as fast as it creates threads, which is to say, really damn fast.
Yes, but only because pthreads does this by creating a new process (that just happens to share some things with its parents, like address space). Ergo, creating threads is just as fast as creating processes because they are nearly the same thing.
The NPTL in 2.6 might have changed this, but I have not read the docs yet.
Yet Apache is still back here creating a process or thread for each and every request (note that there are some ways to speed things up. FastCGI comes to mind, but I don't want to get into the gory details that I don't know enough about). This is not the brightest way to do it in terms of performance, but then, Apache appears to have been designed for universality and configurability over raw throughput.
No, Apache does not create a new process for each request. It creates a pool of child processes which sit waiting for requests. The parent monitors this pool and creates new spare children when too many child processes are busy. This way, most of the time a request comes in there is already a child process sitting idle waiting for work.
CGI does indeed require forking a new process, but there are already great ways to handle this. mod_perl, mod_php, mod_python all do it by embeding the interpreter inside the server. FastCGI keeps a version of the program running (much like apache does with its spares).
You are correct in that your description isn't the brightest way to do things. That's why operating system designers solved these problems years ago.
For static content, again, Apache creates a new process or thread for every request (with some exceptions). If you'll forgive a bit of an oversimplification, it's like writing a program that prints text to the screen. One program calls printf() in a loop. The other program executes a second program which itself displays just one line, and runs that in a loop.
Again, no. Apache will usually not need to create a new process or thread for every connection. The correct analogy would be the other program spawning the required number of children, and then asking them to all printf at the same time.
I still think the 1961 Rosebowl prank is one of the very best. But yeah, these latest MIT ones were lame.
His problem seems to be with the development process of Firefox itself, not with stuff that happening in the main Mozilla trunk. For example, the following projects he doesn't have problems with: XTF, SVG, XForms, E4X, and xulrunner (lifted from the comments).
What I gather this means is that Firefox 1.1 will get some cool new backend features but that its front end stuff will remain mostly the same (excepting the preferences dialog). Is this really a bad thing?
A caching system won't work for the same reason web caches have never caught on in the US - people are terrified of being sued to smithereens for potential copyright infringement. Even if any case would be thrown out of court instantly (by no means certain in the US) the costs would be prohibitive and malicious plaintifs rarely ever get asked to pay costs.
Maybe the caching is just so damn good that you don't notice it. UIUC has a transparent web cache that I doubt 90% (of ~8,000) of the dorm students realize is there.
Also, Akamai is everywhere now. Is it not a caching solution?
I don't think web caches have failed... I just don't think they've been applied to the RSS problem.
Right! But it isn't a faraday cage if you let the internal thing you are trying to protect touch the surface. You've defeated the purpose!
Let's clarify this real quick: I assume you are talking about the inner and outer surfaces, not the volumes.
(digging out my handy Elements of Engineering Electromagnetics, 5th Edition, Rao)
Right, this is a physical explaination of the boundary condition that says the discontinuity in the E field between the sides is equal to the amount of charge present on the conductor. However, you're forgetting to mention that our conductor in this case is a closed surface, and that surfaces are equipotential. Charges don't bunch up on one part of the inner surface, they distribute equally. And assuming the surface is closed, mathematics necessitates that all the internal E fields will cancel.
Otherwise, you would have an imbalence, and would create an E field in a region that does not contain any charge.
True, but unnecessary. The E fields are going to balance perfectly anyways, and cancel themselves out.
Ummm... not really. Assume you have a positive current on the center wire. Using the right hand rule, this creates a positively charged, cirularly symetric E wave that radiates outwards (think throwing a rock in a pond). If you pass the negative equivalent of this signal on the outer shielding, you generate an opposing E field that will directly cancel the internal one. Again, you don't have to ground the external shielding.
Of course, this is all theoretical. As someone else mentioned, the electrons can only propagate so fast, and there will be some delay. But I believe it will work well enough. I'm not sure what frequency they use for these chips, but it can't be too high for something so simple.
Huh? Correct me if I'm wrong, but according to my 4.5 years of EE, Faraday cages work on the principal of Gauss' Law. That is, no EM field can be present inside because there is no charge inside. Wikipedia seems to agree with me.
So where does all this discussion of grounding come in? Googling for Faraday cage brings up this detailed article about building one, but it doesn't mention grounding either.
This page mentions grounding, but only in relations to the instruments, not the table. And this humorous article says grounding is only required if you have to have edges on your cage (we could design passport books so the edges are metal contacts).
I'd be more concerned with whether tin foil is a sufficient conductor for the higher frequencies.
I doubt the printer would let you do that. They're pretty damn smart nowadays, and can probably tell when you switch a yellow and a magenta cartridge.
That's possibly the best one line description of Slashdot I've ever seen.
Unlike Farscape, Babylon5 wasn't canceled. JMS planned for 5 seasons, and although it was rough at times, he got all of them. Everything was wrapped up; the show is done.
I do think there is a movie in the works, but they had better hurry up. The actors keep dying.
(yes, I love both B5 and Farscape... but probably B5 more)
GWB doesn't have any evil plots this election... all the scheming is done by Karl Rove.
At least, that is what some would have me think.
It's even smarter than that! Your little rect in time domain is an inf. sinc in the frequency domain. Of course, after a certain length it dies down to a negligible strength (call this point B). If you wanted to modulate another pulse, to guarantee they will both be exactly recoverable you need to modulate the new pulse up to 2B.
OFDM basically take advantage of the fact that the signal is digital. Instead of modulating the next pulse at 2B, you modulate it so that the next pulse is centered over the first zero crossing of the first pulse. Normally, this would cause horrible aliasing, but since you know the shape of your input data, all you care about are the values at the origin and the zero crossing. You don't care about recovering the two original signals exactly, the value at the origin and the first zero crossing give you enough information to reconstruct them. Aliasing be damned!
This takes advantage of the fact that simpler data is more resistant to noise. If you know what you're sending is a 1 or 0, then the waveform can be horribly degraded before it makes a difference. Contrast this with simple voice data, where a deformation in the wave can't be repaired (you don't know what it should look like). In this case, your encoding scheme introduces noise it knows doesn't matter in order to save bandwidth.
Of course, this is also a form of quadrature multiplexing, which lets you send two signals at the same carrier frequency but differentiate them based on the phase. So that gives you twice the transfer amount you'd normally get above.
(yes, I'm in a communications theory course right now)
I would agree with the ban, if the students were connecting their access points to the universities network. But even the policy statement admits the access points "are connecting to Comcast Cable Modems or to SBC DSL (or other providers) for their Internet access and then are being shared out to other residents within the same or adjacent suites."
So students a paying for their own, non-university internet connection, and sharing it with their neighbors. Taking into account the FCC document, I don't think there is much the university can legally do.
The group I work for is ICS, and we run the largest system of general computing labs on campus. The latest batch of Dells didn't include floppies as part of the standard package and we would have had to pay extra for them. So we just left them out.
Also, for consistency, we've disabled the floppy drives in the other 300 Dells we have, and removed the external drives from all 70 iMacs. You can't sit down at any of our machines and use your floppies anymore.
Instead, we've been pushing technologies like CD-RW, Netfiles (campus wide network storage), and little USB drives. Any one of these media are more durable than floppies; I can't remember how many people over the years have come crying to me because they lost the only copy of their final paper. And there hasn't been any huge uproar over it either among the students or faculty (at least I gaven't noticed any multi-page DI exposes).
Although I'm more centrist than anything else, I understand your point. But I still don't see how the (now) grandparent comment is on topic for this /. discussion.
I thought political humor was supposed to be funny. Your link is just a rabid attack that although it has a few logical points mostly misrepresents the issues (when it isn't launching on an ad hominem attack that is).
The parent post is only tangentially on topic in the sense that it's about politics. This Land was funny because it poked at both candidates; the parent's link is just spiteful.
I honestly think some people -- maybe not the majority but a significant minority -- download movies, songs, TV shows, software, etc because they are addicted.
I'm willing to bet that everyone here knows at least one guy (or girl) who has hundreds of thousands of MP3s, some of which they've only listened to once. Or maybe someone who has dozens of complete TV series. You walk into these people's rooms and there are tons of 100 disc CD spindles sitting on shelves, completely burned and just collecting dust.
I have to believe in these cases that it's a form of internet cleptomania. Not the most damaging of disorders, but still not fucking right.
I was really holding out for Antarctica.
Of course, you need to have your salt handy when reading Hancock's books. But his theories are fun to think about, somewhat like winning the lottery.