In my opinion, every single person who posts anything on the web should never post something online in *.ps.gz format ever, ever again! *... Nothing is a bigger turn off than encountering a interesting document/paper in the archaic.ps or.ps.gz format.
I think that the question of what is the most appropriate file format depends largely on the intended audience for the document. If a document is intended for a wide audience of non-technical users, then text, html or pdf would likely be the best choices. But Knuth's drafts aren't aimed primarily to a general audience.
In the preface to his pre-releases, Knuth says "This booklet contains draft material that I'm circulating to experts in the field, in hopes that they can help remove its most egregarious errors before too many other people see it." So the target audience is the set of theoretical computer scientists and mathematicians - both of which use.ps files as the standard for exchanging documents.
In an interview in the Notices of the American Mathematical Society (vol 49, number 3, pp 318-324), Kunth was asked about how many people cash his checks. Here's his response:
"There's one man who lives near Frankfurt who would probably have more than $1,000 if he cashed all the checks I've sent him. There is man in Los Gatos, California, whom I've never met, who cashes a check for $2.56 about once a month, and that's been going on for some years now. Altogether I've written more than 2,000 checks over the years, and the average amount exceeds $8.00 per check. Even if everybody cashed their checks, it wouls still be more than worth it to me to know that my books are getting better."
If you like you can say that the answer is "infinity", since "infinity" isn't a number either.
Just saying infinity doesn't tell the whole story, because the function f(x)=1/x diverges in different directions as x approaches 0. From the left, the limit is negative infinity, and from the right it is positive infinity.
1/0 is defined as undefined, I think that just means no one has ever figured out the right answer.
No, this means that the quantity 1/0 is literally not defined. Within the field of rational numbers (and also within the reals and complex numbers), there is no number x such that 0 * x = 1, i.e. 0 has no multiplicative inverse. For any number x, 1/x represents the multiplicative inverse of x. Since 0 has no multiplicative inverse, 1/0 is undefined.
Teaching yourself from a math book can work well, but I think that it is also important to have a knowlegable person you can consult. The problem with teaching yourself in isolation is that when you get stuck, you don't have anyone to pull you out. The teach-yourself-calculus-type books try to minimize this kind of thing, but chances are it will still happen.
If you have any friends who are math geeks, they'd probably be glad to answer questions and talk math with you. If you don't have any math-geek friends, then perhaps you could talk with your daughter's teacher, or hire a tutor, although tutors can be pricey.
IAAM, and I agree with your explanation, with one nitpick:
Specifically (in math at least) a theory is a set of related theorems.
I would say that a mathematical theory (ie graph theory, number theory, etc) encompasses not only the theorems, but also other related things such as definitions, axioms, conjectures, unsolved problems in the area, etc.
The reasoning goes, that since the human population is always growing, it is more probable that I would be born in the 20th century than in any century prior.
The probability that you were born in the 20th century is either 0 or 1, since that particular event has already occured, so we should introduce a randomly selected human into the dialogue.
If a person (let's call him X) is chosen at random from the set of all people who have ever or will ever live on the earth, the probability that X was born in the 20th century is greater than the probability that he was born in any particular earlier century, since the 20th century saw more births than any previous century.
But wouldn't it then be even more probable if I were born in the 25th century?
Assuming that the 25th century will have more births than any previous century, X would have a higher probability of being born in the 25th than in any previous century.
In fact, the chances of my being born in the 20th century would be vanishingly small.
Hmmm. The problem goes back to the premise that the human population is always growing. This cannot continue to be true forever. It will eventually have to level off because the Earth only has enough resources, space, etc to support a finite number of people (which also limits the number of births possible in a given century). Also note that the number of centuries that humans will populate the earth (call it N) is finite.
This implies some important stuff about the probability distribution of which century X was born in. The probability distribution is discrete. Thus each century has a positive probability of being the century of X's birth. If N is large enough for the population to level off, then the probability distribution must level off too. Although the probability that X was born in the 20th century could be made arbitrarily small, the proportion
(Probability X is born in 20th century)/(Probability X is born in nth century)
where n is any century in the distant future has a positive bound. In other words, the probability that X is born in the 20th century isn't so much smaller than the probability that x is bron in the 25th that it can be discounted.
I considered a car battery, but most of the nurses would have trouble pushing both cart and battery.
Is the weight of a car battery really an issue? Sure they are heavy, but they are a lot lighter than a patient in a wheelchair, or one of those roll-around stretchers - both of which are routinely moved by nurses.
Placing a large battery on the bottom of the cart would also give it a low center of gravity increase its stability.
I once took a course in mathematical modeling, and we did some great stuff with simulating the motion of a spacecraft in earth orbit. We simplified the real problem by only using two dimensions, keeping the spacecraft confined to a plane that intersects the center of the earth.
Another simplification was that we didn't use a continuous flow of time. We cut the flow of time into discrete ticks (minutes or seconds), and calculated the change in position of the spacecraft from one tick to the next. The spacecraft is given an initial position and velocity, which are used to calculate the position and velocity in the next tick (the x and y components being done separately).
From one tick to the next and for each direction (x and y), it breaks down into:
1. calculating the gravitational force exerted on the spacecraft by the earth using the masses of the earth and the spacecraft, the universal gravvitation constant, and the distance from the center of the earth to the spacecraft.
2. Using a = F/m to find the accelleration of the spacecraft due to gravity.
3. Using v_new = v_old + a * delta (delta is the length of a tick) to get the new velocity.
4. Using p_new = p_old + v_new * delta to get the new position.
5. Repeat.
You can do some neat stuff with this. The two that I remember doing were
1. Start with the object at say, 100 miles up, and find the minimum velocity needed to stay in orbit, and the minimum velocity needed to escape from the earth.
2. Bring the moon into play and find the velocity needed to do a figure 8 orbit around the earth and the moon.
One problem with this is how to look at the orbits. We used Gnuplot.
This is quite heavy on physics, which might lose some students, so I'm not sure if it's a good assignment for an intro-level course, but I do remember it being a lot of fun.
Fox has a long history of utterly failing to pay attention to the worthwhileness of their shows...
That's the truth. Married with Children is a prime example. It was one of the shows that helped launch the network, and they showed no respect for that. They repeatedly changed the timeslot, and eventually moved it to Saturday night. The worst, though, was that they didn't produce a final episode. They cancelled it after all the season 11 episodes were taped, so there was never a finale That's a pretty rotten send-off for a show that ran for over a decade.
I remember seeing a really funny ad in a BBS magazine in the early 90s. I may have forgotten a few details, but I believe that the product was a program called Personal Internet Mail Processor. The logo with a globe wearing a pink hat with a purple feather.
anyone with a grounding in mathematical principles knows that there is no such thing as a binary hypercube, any more than there is such a thing as a square circle
Sure there is.
The n-dimensional cube graph, aka the n-dimensional hypercube graph is the graph consisting of 2^n vertices, each corresponding to one of the binary words of length n. Two vertices are adjacent if and only if the binary words they represent differ in exactly one bit position. It has n*2^(n-1)edges.
Binary hypercubes and Gray codes have been used in tons of applications for a long time. They are used in computer architecture, database design, digital communications, solving the chinese ring puzzle, etc.
In short, there is such a thing as a Binary Hypercube.
I imagine the average in the US is at least an hour a day of television viewing. Truly a waste.
You can't really compare watching TV with playing computer games when you're talking about wasting time. The major difference is that video games require interaction. Many people watch TV casually while doing other things. For example, my TV is rarely turned off when I'm awake at home, although the vast majority of the time it is in the background while I'm doing other things.
I borrowed a friend's copy of Oh Brother Where Art Thou? and ripped mp3's without any errors. Did he get a disc with defective copy protection? Or is Fat Chuck's list defective?
I ripped the same CD with no problem. My guess is that either the copy protection is ineffective or that possibly some of the early copies were sold with no copy protection.
I suppose that a conspiracy theorist might think that some nonprotected discs are actually advertised as having copy protection in order to stick the return-a-stack-of-CDs activists with a a few hundred dollars in nondefective CDs that they cannot return.
Yes. CDs encode data using two Reed-Solomon Codes. Each sample (44,100 per second) records two amplitude measurements (one for each channel), as a 16-bit words. Thus there are 4 bytes/sample. Measurements from 6 consecutive samples are grouped together, and encoded using the Reed Solomon code RS(2^8,5). This adds 4 bytes of redundancy to the 24 bytes of data. After that, the 28 resultant bytes of data are interleaved, then encoded in a a shortened Reed-Solomon code that adds another 4 bytes of redundancy. Then one more byte is added that is used for some type of control purpose (i don't know exactly). After that, a translation is used to make the physical reading/writing more feasable, three bits are added for some reason after the translation, then a 27 bit word is added for syncing purposes.
Overall 6 "ticks" of stereo music contain 196 bits of data, which is expanded to 588 bits written to the disc. The end result is that any error burst of 8871 or fewer bits of data on the disc can be corrected.
that's because they are seperate words that already MEAN possesive. its is NOT a seperate word from it, it just has an affix stuck on. and in case you hadn't noticed, it's the ONLY word where the possesive affix "can't" have the appostraphe.
The reason that "it's" has an apostrophe is because it is a contraction of the phrase "it is".
There was an episode of Alf that aired October 9, 1989, in which ALF buys stocks and some other things online. The episode was titled "We're in the money". The episode guide is available at http://epguides.com/ALF/guide.shtml.
David
Doing this with GnuPlot
on
GPS Drawings
·
· Score: 1
I've been doing this sort of thing for a while now. I made a cable for my garmin etrex, and I use the gpstrans program to download the track data into into a file (in decimal degree format). After that, I use a simple perl script to convert the lines of data to just lattitude/longitude cooridinates, and then plot it using gnuplot. I then do the same thing with the waypoints. You can plot the track with dots and the waypoints with points, and get a nice map of where you've been, along with where your waypoints are located. I've kept a cumulative file of all my track data, and I've got a nice map of all my trips from the past year.
Here are the scripts:
Converting a track to x/y coordinates:
#!/usr/bin/perl
$filename = $ARGV[0];
open (F, $filename) or die "bad filename - ARGH!";
Some of the older, early 90's model Zenith TVs have a service mode. Be forewarned: You can screw your TV up with this mode if you don't know what you're doing. To enter the mode, hold down the menu button until the menu disappears. Then press 9, 8, 7, 6, enter. You can also enter the mode by pressing three buttons on the tv at the same time, but I'm not sure what they are.
Again, I don't advise anyone to do this to good TV. It may be possible to damage your TV, and you can get it into some modes that are difficult to get out of.
If you thought the FBI wiretapping Little Nicky Scarfo on only a search warrant was horrifying, consider the bully stick that will be bandied about now. Encryption is bad. Terrorists using encryption got past all our intelligence. Outlaw encryption now! If we didn't have to go through all that judicial rigamarole to keep an eye on terrorists, we would have done better.
How is outlawing encryption going to prevent anyone, especially terrorists outside the US from using it? While many politicians may not understand the technicalities of encryption, few would not recognize the futility of "banning" it.
Science never claimed that the world was flat, or that the Earth was at the center of the universe.
Science has supported many theories of the universe that were later shown to be incorrect. It was long believed that the earth was at least the center of the solar system. Ptolemy, trying to reconcile the motions of the planets, developed his system of epicycles - based on observation. This was widely accepted until the Copernican solar system became widely known to European Academics, and Keplar's laws gave a much more accurate model of planetary motion.
> Sure, if you have 1 object you can arrange it in only one way. But if you have no objects (zero), there is nothing to arrange. Nothing to be done.
Yes, there's nothing to be done, and there is exactly one way that you can do nothing. How many ways can you arrange zero books on a bookshelf? There's no choice there, and hence only one possiblilty - your shelf is empty.
Slashdot Mirror
In my opinion, every single person who posts anything on the web should never post something online in *.ps.gz format ever, ever again! * ... .ps or .ps.gz format.
.ps files as the standard for exchanging documents.
Nothing is a bigger turn off than encountering a interesting document/paper in the archaic
I think that the question of what is the most appropriate file format depends largely on the intended audience for the document. If a document is intended for a wide audience of non-technical users, then text, html or pdf would likely be the best choices. But Knuth's drafts aren't aimed primarily to a general audience.
In the preface to his pre-releases, Knuth says "This booklet contains draft material that I'm circulating to experts in the field, in hopes that they can help remove its most egregarious errors before too many other people see it." So the target audience is the set of theoretical computer scientists and mathematicians - both of which use
In an interview in the Notices of the American Mathematical Society (vol 49, number 3, pp 318-324), Kunth was asked about how many people cash his checks. Here's his response:
"There's one man who lives near Frankfurt who would probably have more than $1,000 if he cashed all the checks I've sent him. There is man in Los Gatos, California, whom I've never met, who cashes a check for $2.56 about once a month, and that's been going on for some years now. Altogether I've written more than 2,000 checks over the years, and the average amount exceeds $8.00 per check. Even if everybody cashed their checks, it wouls still be more than worth it to me to know that my books are getting better."
If you like you can say that the answer is "infinity", since "infinity" isn't a number either.
Just saying infinity doesn't tell the whole story, because the function f(x)=1/x diverges in different directions as x approaches 0. From the left, the limit is negative infinity, and from the right it is positive infinity.
1/0 is defined as undefined, I think that just means no one has ever figured out the right answer.
No, this means that the quantity 1/0 is literally not defined. Within the field of rational numbers (and also within the reals and complex numbers), there is no number x such that 0 * x = 1, i.e. 0 has no multiplicative inverse. For any number x, 1/x represents the multiplicative inverse of x. Since 0 has no multiplicative inverse, 1/0 is undefined.
Teaching yourself from a math book can work well, but I think that it is also important to have a knowlegable person you can consult. The problem with teaching yourself in isolation is that when you get stuck, you don't have anyone to pull you out. The teach-yourself-calculus-type books try to minimize this kind of thing, but chances are it will still happen.
If you have any friends who are math geeks, they'd probably be glad to answer questions and talk math with you. If you don't have any math-geek friends, then perhaps you could talk with your daughter's teacher, or hire a tutor, although tutors can be pricey.
IAAM, and I agree with your explanation, with one nitpick:
Specifically (in math at least) a theory is a set of related theorems.
I would say that a mathematical theory (ie graph theory, number theory, etc) encompasses not only the theorems, but also other related things such as definitions, axioms, conjectures, unsolved problems in the area, etc.
The reasoning goes, that since the human population is always growing, it is more probable that I would be born in the 20th century than in any century prior.
The probability that you were born in the 20th century is either 0 or 1, since that particular event has already occured, so we should introduce a randomly selected human into the dialogue.
If a person (let's call him X) is chosen at random from the set of all people who have ever or will ever live on the earth, the probability that X was born in the 20th century is greater than the probability that he was born in any particular earlier century, since the 20th century saw more births than any previous century.
But wouldn't it then be even more probable if I were born in the 25th century?
Assuming that the 25th century will have more births than any previous century, X would have a higher probability of being born in the 25th than in any previous century.
In fact, the chances of my being born in the 20th century would be vanishingly small.
Hmmm. The problem goes back to the premise that the human population is always growing. This cannot continue to be true forever. It will eventually have to level off because the Earth only has enough resources, space, etc to support a finite number of people (which also limits the number of births possible in a given century). Also note that the number of centuries that humans will populate the earth (call it N) is finite.
This implies some important stuff about the probability distribution of which century X was born in. The probability distribution is discrete. Thus each century has a positive probability of being the century of X's birth.
If N is large enough for the population to level off, then the probability distribution must level off too. Although the probability that X was born in the 20th century could be made arbitrarily small, the proportion
(Probability X is born in 20th century)/(Probability X is born in nth century)
where n is any century in the distant future has a positive bound. In other words, the probability that X is born in the 20th century isn't so much smaller than the probability that x is bron in the 25th that it can be discounted.
I considered a car battery, but most of the nurses would have trouble pushing both cart and battery.
Is the weight of a car battery really an issue? Sure they are heavy, but they are a lot lighter than a patient in a wheelchair, or one of those roll-around stretchers - both of which are routinely moved by nurses.
Placing a large battery on the bottom of the cart would also give it a low center of gravity increase its stability.
I once took a course in mathematical modeling, and we did some great stuff with simulating the motion of a spacecraft in earth orbit. We simplified the real problem by only using two dimensions, keeping the spacecraft confined to a plane that intersects the center of the earth.
.
Another simplification was that we didn't use a continuous flow of time. We cut the flow of time into discrete ticks (minutes or seconds), and calculated the change in position of the spacecraft from one tick to the next. The spacecraft is given an initial position and velocity, which are used to calculate the position and velocity in the next tick (the x and y components being done separately).
From one tick to the next and for each direction (x and y), it breaks down into:
1. calculating the gravitational force exerted on the spacecraft by the earth using the masses of the earth and the spacecraft, the universal gravvitation constant, and the distance from the center of the earth to the spacecraft.
2. Using a = F/m to find the accelleration of the spacecraft due to gravity.
3. Using v_new = v_old + a * delta (delta is the length of a tick) to get the new velocity
4. Using p_new = p_old + v_new * delta to get the new position.
5. Repeat.
You can do some neat stuff with this. The two that I remember doing were
1. Start with the object at say, 100 miles up, and find the minimum velocity needed to stay in orbit, and the minimum velocity needed to escape from the earth.
2. Bring the moon into play and find the velocity needed to do a figure 8 orbit around the earth and the moon.
One problem with this is how to look at the orbits. We used Gnuplot.
This is quite heavy on physics, which might lose some students, so I'm not sure if it's a good assignment for an intro-level course, but I do remember it being a lot of fun.
Thats easy. Just make sure N is 1.
Or make sure P is 0.
Or both...
Fox has a long history of utterly failing to pay attention to the worthwhileness of their shows ...
That's the truth. Married with Children is a prime example. It was one of the shows that helped launch the network, and they showed no respect for that. They repeatedly changed the timeslot, and eventually moved it to Saturday night. The worst, though, was that they didn't produce a final episode. They cancelled it after all the season 11 episodes were taped, so there was never a finale That's a pretty rotten send-off for a show that ran for over a decade.
I remember seeing a really funny ad in a BBS magazine in the early 90s. I may have forgotten a few details, but I believe that the product was a program called Personal Internet Mail Processor. The logo with a globe wearing a pink hat with a purple feather.
anyone with a grounding in mathematical principles knows that there is no such thing as a binary hypercube, any more than there is such a thing as a square circle
Sure there is.
The n-dimensional cube graph, aka the n-dimensional hypercube graph is the graph consisting of 2^n vertices, each corresponding to one of the binary words of length n. Two vertices are adjacent if and only if the binary words they represent differ in exactly one bit position. It has n*2^(n-1)edges.
Binary hypercubes and Gray codes have been used in tons of applications for a long time. They are used in computer architecture, database design, digital communications, solving the chinese ring puzzle, etc.
In short, there is such a thing as a Binary Hypercube.
I imagine the average in the US is at least an hour a day of television viewing. Truly a waste.
You can't really compare watching TV with playing computer games when you're talking about wasting time. The major difference is that video games require interaction. Many people watch TV casually while doing other things. For example, my TV is rarely turned off when I'm awake at home, although the vast majority of the time it is in the background while I'm doing other things.
I borrowed a friend's copy of Oh Brother Where Art Thou? and ripped mp3's without any errors. Did he get a disc with defective copy protection? Or is Fat Chuck's list defective?
I ripped the same CD with no problem. My guess is that either the copy protection is ineffective or that possibly some of the early copies were sold with no copy protection.
I suppose that a conspiracy theorist might think that some nonprotected discs are actually advertised as having copy protection in order to stick the return-a-stack-of-CDs activists with a a few hundred dollars in nondefective CDs that they cannot return.
Yes. CDs encode data using two Reed-Solomon Codes. Each sample (44,100 per second) records two amplitude measurements (one for each channel), as a 16-bit words. Thus there are 4 bytes/sample. Measurements from 6 consecutive samples are grouped together, and encoded using the Reed Solomon code RS(2^8,5). This adds 4 bytes of redundancy to the 24 bytes of data. After that, the 28 resultant bytes of data are interleaved, then encoded in a a shortened Reed-Solomon code that adds another 4 bytes of redundancy. Then one more byte is added that is used for some type of control purpose (i don't know exactly). After that, a translation is used to make the physical reading/writing more feasable, three bits are added for some reason after the translation, then a 27 bit word is added for syncing purposes.
Overall 6 "ticks" of stereo music contain 196 bits of data, which is expanded to 588 bits written to the disc. The end result is that any error burst of 8871 or fewer bits of data on the disc can be corrected.
that's because they are seperate words that already MEAN possesive. its is NOT a seperate word from it, it just has an affix stuck on. and in case you hadn't noticed, it's the ONLY word where the possesive affix "can't" have the appostraphe.
The reason that "it's" has an apostrophe is because it is a contraction of the phrase "it is".
There was an episode of Alf that aired October 9, 1989, in which ALF buys stocks and some other things online. The episode was titled "We're in the money". The episode guide is available at http://epguides.com/ALF/guide.shtml.
David
I've been doing this sort of thing for a while now. I made a cable for my garmin etrex, and I use the gpstrans program to download the track data into into a file (in decimal degree format). After that, I use a simple perl script to convert the lines of data to just lattitude/longitude cooridinates, and then plot it using gnuplot. I then do the same thing with the waypoints. You can plot the track with dots and the waypoints with points, and get a nice map of where you've been, along with where your waypoints are located. I've kept a cumulative file of all my track data, and I've got a nice map of all my trips from the past year.
/\t/, $line;
/\t/, $line;
Here are the scripts:
Converting a track to x/y coordinates:
#!/usr/bin/perl
$filename = $ARGV[0];
open (F, $filename) or die "bad filename - ARGH!";
while ($line = ){
$line =~s/T.....................//g;
@coord = split
chomp $coord[1];
chomp $coord[0];
print "$coord[1] $coord[0]\n";
}
close(F);
Converting a waypoint file to x/y coordinates:
#!/usr/bin/perl
$filename = $ARGV[0];
open (F, $filename) or die "bad filename - ARGH!";
while ($line = ){
$line =~ s/.*00:00.//g;
@coord = split
chomp $coord[1];
chomp $coord[0];
print "$coord[1] $coord[0]\n";
}
close(F);
Some of the older, early 90's model Zenith TVs have a service mode. Be forewarned: You can screw your TV up with this mode if you don't know what you're doing. To enter the mode, hold down the menu button until the menu disappears. Then press 9, 8, 7, 6, enter. You can also enter the mode by pressing three buttons on the tv at the same time, but I'm not sure what they are.
Again, I don't advise anyone to do this to good TV. It may be possible to damage your TV, and you can get it into some modes that are difficult to get out of.
How is outlawing encryption going to prevent anyone, especially terrorists outside the US from using it? While many politicians may not understand the technicalities of encryption, few would not recognize the futility of "banning" it.
This is very relavent. TV coverage could be compromised in NYC now, since many of the TV Station antennas are on the WTC.
Science has supported many theories of the universe that were later shown to be incorrect. It was long believed that the earth was at least the center of the solar system. Ptolemy, trying to reconcile the motions of the planets, developed his system of epicycles - based on observation. This was widely accepted until the Copernican solar system became widely known to European Academics, and Keplar's laws gave a much more accurate model of planetary motion.
> Sure, if you have 1 object you can arrange it in only one way. But if you have no objects (zero), there is nothing to arrange. Nothing to be done.
Yes, there's nothing to be done, and there is exactly one way that you can do nothing. How many ways can you arrange zero books on a bookshelf? There's no choice there, and hence only one possiblilty - your shelf is empty.
ACK! That's supposed to say 0! = 1. (Next time I'm I'll actually read the preview.)