NTP solved this ages ago by distributing atomic clock accuracy through the network.
Wrong. NTP is rarely as good as a millisecond. Atomic clocks should be accurate to better than a microsecond.
There is an IETF effort, TicToc, intended to help improve time transfer to better than NTP accuracy, but that requires router assistance (i.e., participation by the ISP), as routers and switches will introduce large and indeterminate delays by atomic clock standards.
Google has gone positively copyright absolutist - not just in YouTube (which, of course, grew up on a steady diet of infringement), but also in Adwords and maybe Adsense.
Adwords now disallows ads with phrases like "music videos" or "Internet TV," under the theory that any site advertising such must be guilty of, not just infringement, but "hacking and cracking." As their standard of proof is "guilty until proven innocent," arguing with them is fairly frustrating...
Most video material comes, originally, from a camera of some sort. (Obviously, this isn't the case for animation.) All of the HD camera systems I know of record in H.264, MPEG-4 or MPEG-2. (It might be called HD-DV or something else, but it's MPEG compressing under the hood.) So, if that gives H.264 an advantage, there isn't much that can be done about it. It will take a long time to replace all of the camera gear out there...
H.264 doesn't actually use a DCT, but a non-exact integer approximation to a DCT, the Integer Cosine Transform, which is exactly invertible,, at the cost of a slightly loss of accuracy in the transform coefficients . (Floating point DCTs have rounding errors, and thus are not exactly invertible. If content is encoded multiple times, then the numerical noise introduced by this will accumulate to troublesome levels.)
What you want is IPTV over multicast. A number of universities have done this - one is the University of Wisconsin at Madison, which has a pretty bare bones approach using IP multicast and Apple Quicktime. They are also pretty good about giving technical clue if you run into trouble and ask nicely. If you want to spend more money, there is the HaiVision Video Furnace, which is used by, e.g., Brown University.
I have no idea if your contract with Comcast will let you do this, but I believe that the Universities do it by restricting use to only people on campus, so you might be able to do the same.
I think you are mixing up the reception to the Abduction from the Seraglio (where the "too many notes" occurred, supposedly said by Joseph II, first recounted in an early Mozart biography) and the production of the Marriage of Figaro (the "put it back moment," recounted in da Ponte's memoirs). Both of these have historical grounding, but of course, both are also disputed (little of note about Mozart's life isn't).
While the plot of Amadeus is pretty unhistorical, many of its incidents have some historical grounding, and that is the case for these two incidents.
By the way, this was before copyright, and Mozart only received a flat fee for the Abduction, and I believe for Figaro as well. This failure to receive royalties obviously hindered him from creating any subsequent works of note.
14 years was good enough for Thomas Jefferson, and it is good enough for me.
The people granted a temporary monopoly on some intellectual property as an experiment to further the useful arts, and they can certainly take some of it back.
Yes, the Titan II stuck out in our strategic arsenal for a long time. However, such big bombs would also be good as bunker busters, so they may have had multiple (potential) uses.
If the informal nuclear test ban between the US and the USSR had not broken down, there wouldn't have been this series of tests (nor the Tsar Bomba test) and we wouldn't know about EMP (at least, openly). It would be just a gleam in some physicists eye - which could be much more destabilizing.
So, here is a case where the failure of arms control may have had positive consequences.
a) If a bomb's radiation would make it harder to see what was up there (like incoming Russian missiles!); b) If an explosion would do any damage to objects nearby; c) If the Van Allen belts would move a blast down the bands to an earthly target (Moscow! for example); and — most peculiar — d) if a man-made explosion might "alter" the natural shape of the belts.
a. Yes, especially in the radio. b. Yes, in a fairly predictable fashion (from heat, gamma rays). c. No d. Yes, for a short while, sort of like a solar flare. That can actually cause a "geomagnetically induced current," which could be a problem for long electrical transmission lines.
However, the real find from the test was the prompt EMP, which was not anticipated. (See my post further down on that one.)
This test series (specifically, Starfish Prime) uncovered the electromagnetic pulse (EMP) effect, an unexpected side effect of nuclear explosions at altitude. The gamma rays from a high altitude burst hit atoms and thus eject electrons high in the atmosphere over a wide area, more or less simultaneously, and the current from the ejected electrons can cause a very wide-spread electromagnetic pulse, which can knock out power lines and electronics at great distances (> 1000 km).
So, I guess we can call Allen the father of the EMP, although I am not sure he would have wanted the honor.
I know of large US companies that do not allow executives to take their laptops into China, as they assume that its contents will be read (at the border or elsewhere). So, they get a sanitized laptop for the trip. Sounds extreme, but there have been cases of industrial espionage in the past.
Hayabusa was not a failure, failure of the sample return or no. It returned a lot of information about a near Earth asteroid including (to me) the very fundamental result that the regolith appears to be well mixed. This means that the asteroid is not just a lump of rubble but something is stirring material from inside to the surface and back again. This will prove very significant when we start doing engineering on asteroids (such as mining or setting up bases).
Traveling in deep space is tough. All of the countries that have done it have suffered through a pretty steep learning curve. Japan's space agency should be congratulated for pulling this off; I hope that the (undeserved) bad press doesn't make them shy from trying innovative missions such as Hayabusa in the future.
We photographed many, many alien planets before this one: every time anyone pointed a camera at the sky, in fact. We've just not spotted any planets in those other images (yet).
Maybe (in a handful of all of the millions of images taken of astronomical objects), but I would doubt it. Exo-Planetary imagery is tough and is generally done of new systems in the IR (young planets are hot, and thus glow brighter). If by "photographed" you mean "an image with at least one pixel that could be recognized as an exo-planet if only we knew where to look," it's not likely that even the Hubble has captured any planets unawares. It's for sure not common.
The key word in the title is "confirmed." Readers may remember that there were 2 separate sets of planets photographed in papers published in 2008. Now, we are sure (not that there was much doubt) that one of them is truly orbiting its primary star.
Suppose that Mr. Smith has two children, at least one of whom is a son. What is the probability both children are boys?
Intuition would suggest that the answer should be 1/2, since the sex of one child is independent of the sex of the other. And indeed, had he been told which child was a boy (say, the younger one), this reasoning would be sufficient. But since the boy could be either the younger or the older child, the analysis is more subtle. Devlin started by listing the children’s sexes in the order of their birth:
Boy, girl Boy, boy Girl, boy
Since one child is a boy, we know that girl, girl isn’t a possibility. Of the three approximately equally likely possibilities, one has two boys and two have a girl and a boy — so the probability of two boys is 1/3, not 1/2, Devlin concluded.
But this makes no sense whatsoever. For simplicity, I will assume that the human sex ratio is 1:1, and ignore the possibility of identical twins. I will also ignore the possibility of the "Monty Hall effect" - i.e., that there is other information that skews reporting of the first child. (Without this, anything can go. Suppose that I belong to a religion that believes that the birth of two boys in a row is deeply shameful and should never be mentioned. If you know that, saying that I have one boy make the probability of a girl 100%. Any other probability you might want is also possible, and so this has to be ruled out.)
To make the English clearer, suppose that I am on a beach with equal numbers of blue (B) and green (G) pebbles, and I pick two up, carefully noting the color of each.
So, an observer who just knows I have picked up two pebbles (but not the color of either) has the following probability table
BG - 25 % BB - 25 % GB - 25 % GG - 25 %
Ok, I continue to walk along and meet up with the observer, and as I do so one pebble drops at random out of my bag. It is Blue (B). The observer sees this, and modifies his probability table as follows :
New probability = old probabiity x probability of having a Blue pebble fall out (renormalized to sum to unity, if necessary). This yields
BG - 25 % BB - 50 % GB - 25 % GG - 0 %
So, the problem with the original "Birthday Problem" analysis is that, while there are indeed three choices, one with a second boy, and two with a girl, the probability of these choices are not equal ! With the correct probabilities, the chance that the second child is a boy is 50%
I would argue that, in the universe of these problems (where you are not supposed to need additional, unstated, information beyond basic things like people want to minimize jail time and maximize revenue), this is the correct analysis of the original "Birthday Problem," and the one presented in the original article is wrong.
The original "Tuesday Birthday Problem" analysis is likewise wrong, in the same fashion.
Here is my reasoning. First, the boy could be one of an identical twin, in which case the other child is certainly a boy (maybe born on Tuesday, maybe not). The probability of that is 0.004 (0.4%), according to this.
Of course, with probability 1.000 - 0.004 = 0.996 the children are not identical twins, in which case the probability of a boy is 0.512195 (the human live birth sex ratio).
So, the probability of a second boy is
0.004 + ( 0.996 * 0.512195) = 0.514146
Whatever the sex ratio, you gain 1/2 of the probability of identical twins if the other child is a boy (and you lose that amount if the other child is a girl, for the same reason).
I am assuming in all of this live births (i.e., that the children were not stillborn and did not miscarry), but the statement is "I have" not "I had," implying live births.
The easiest way to find oil in gravity maps from what I understand is to look for salt domes (big bubbles of salt), which are much less dense than the surrounding rock.
The big low in the Indian ocean is thought to be related to subduction and may even be a "wake" from the recent passage of the Indian subcontinent as the plate drifted North. I don't think it is a huge salt dome.
Grace and GOCE are completely different experiments, which measure different (but related) things about the Earth's gravity field. Grace tracks the motions of a pair of satellites, which GOCE uses pairs of accelerometers. Different data types, different measurement errors, different types of systematic errors. I think it is well worth running both experiments.
The data is a model of what sea level would be, for a completely water covered Earth, assuming that the oceans had uniform density and no currents, minus the mean sea level. This sounds complicated, but it is pretty easy to calculate, assuming you have the gravity data.
There is a fascinating deep area in the Indian ocean (-100M) and a high area near Iceland (+80M), proving conclusively that our world is not homogeneous in terms of density (or practically any other measure). Does anyone know whether these anomalies correspond to known geographic phenomena? Deposits of heavy metals perhaps, or hotspots where the mantle is thinner? I know little about geodetic stuff, but I'm curious about the reasons for wrinkles in the data set."
Something that is maybe not so clear from the discussion in TOA, this is an accelerometer mission, and thus reveals a high pass filtering (AKA high-harmonic geoid signatures) of the gravity field. I am not sure if the geoid map in the BBC article is entirely from GOCE data, or if it has other data filling in the low spatial frequencies - it looks pretty similar to older geoid maps.
You might want to read this paper, which points out that
"The interpretation of GOCE geoid and gravity anomaly maps in terms of structure and dynamics of the Earth is neither simple nor straightforward."
You can see things like typography, sea-mounts (modern gravity data is very good at detecting these), mountain ranges (these are like icebergs, made of lighter material with deep roots, and so are typically actually geoid lows), subduction zones, etc. Since what's going on may be determined by mass / density changes in the deep mantle, figuring out what the observed structures mean can be tough.
However, the scientific interest in these gravity data largely centers around changes in gravity, and many of these are more straightforward. Among the signatures of interest are ocean current changes (might change the dynamic sea level by 10 cm), ice formation and melting (for example, of the Greenland ice sheet), and the global water balance on land (if it rains, it changes the mass loading of the ground, and thus the geoid). Data such as these, and the data from GRACE, are becoming more and more important in the study of global geodynamics. The literally show what's happening on the ground, in basically real time.
I have (quickly) read the paper. The author does a stichometric analysis and concludes that there is a mathematical structure in the texts (which seems reasonably solid) and that (as Aristotle said), Plato was thus a Pythagorean (they were big on numerical mysticism). I would regard that as a "definite maybe." And that's pretty much it. To go from that to that he "anticipated the Scientific Revolution 2,000 years before Isaac Newton" is, IMHO, a stretch.
Slashdot Mirror
NTP solved this ages ago by distributing atomic clock accuracy through the network.
Wrong. NTP is rarely as good as a millisecond. Atomic clocks should be accurate to better than a microsecond.
There is an IETF effort, TicToc, intended to help improve time transfer to better than NTP accuracy, but that requires router assistance (i.e., participation by the ISP), as routers and switches will introduce large and indeterminate delays by atomic clock standards.
Google has gone positively copyright absolutist - not just in YouTube (which, of course, grew up on a steady diet of infringement), but also in Adwords and maybe Adsense.
Adwords now disallows ads with phrases like "music videos" or "Internet TV," under the theory that any site advertising such must be guilty of, not just infringement, but "hacking and cracking." As their standard of proof is "guilty until proven innocent," arguing with them is fairly frustrating...
Most video material comes, originally, from a camera of some sort. (Obviously, this isn't the case for animation.) All of the HD camera systems I know of record in H.264, MPEG-4 or MPEG-2. (It might be called HD-DV or something else, but it's MPEG compressing under the hood.) So, if that gives H.264 an advantage, there isn't much that can be done about it. It will take a long time to replace all of the camera gear out there...
H.264 doesn't actually use a DCT, but a non-exact integer approximation to a DCT, the Integer Cosine Transform, which is exactly invertible,, at the cost of a slightly loss of accuracy in the transform coefficients . (Floating point DCTs have rounding errors, and thus are not exactly invertible. If content is encoded multiple times, then the numerical noise introduced by this will accumulate to troublesome levels.)
What you want is IPTV over multicast. A number of universities have done this - one is the University of Wisconsin at Madison, which has a pretty bare bones approach using IP multicast and Apple Quicktime. They are also pretty good about giving technical clue if you run into trouble and ask nicely. If you want to spend more money, there is the HaiVision Video Furnace, which is used by, e.g., Brown University.
I have no idea if your contract with Comcast will let you do this, but I believe that the Universities do it by restricting use to only people on campus, so you might be able to do the same.
IANAL, but I doubt Wicked Lasers is very worried.
Movies get copyright protection, or trademark protection.
Hardware gets patent protection.
If George Lucas has a (design) patent on the light saber, it's expired by now.
Of course.
I think you are mixing up the reception to the Abduction from the Seraglio (where the "too many notes" occurred, supposedly said by Joseph II, first recounted in an early Mozart biography) and the production of the Marriage of Figaro (the "put it back moment," recounted in da Ponte's memoirs). Both of these have historical grounding, but of course, both are also disputed (little of note about Mozart's life isn't).
While the plot of Amadeus is pretty unhistorical, many of its incidents have some historical grounding, and that is the case for these two incidents.
By the way, this was before copyright, and Mozart only received a flat fee for the Abduction, and I believe for Figaro as well. This failure to receive royalties obviously hindered him from creating any subsequent works of note.
14 years was good enough for Thomas Jefferson, and it is good enough for me.
The people granted a temporary monopoly on some intellectual property as an experiment to further the useful arts, and they can certainly take some of it back.
Yes, the Titan II stuck out in our strategic arsenal for a long time. However, such big bombs would also be good as bunker busters, so they may have had multiple (potential) uses.
If the informal nuclear test ban between the US and the USSR had not broken down, there wouldn't have been this series of tests (nor the Tsar Bomba test) and we wouldn't know about EMP (at least, openly). It would be just a gleam in some physicists eye - which could be much more destabilizing.
So, here is a case where the failure of arms control may have had positive consequences.
I will give this a shot. I assume you mean these.
a) If a bomb's radiation would make it harder to see what was up there (like incoming Russian missiles!); b) If an explosion would do any damage to objects nearby; c) If the Van Allen belts would move a blast down the bands to an earthly target (Moscow! for example); and — most peculiar — d) if a man-made explosion might "alter" the natural shape of the belts.
a. Yes, especially in the radio.
b. Yes, in a fairly predictable fashion (from heat, gamma rays).
c. No
d. Yes, for a short while, sort of like a solar flare. That can actually cause a "geomagnetically induced current," which could be a problem for long electrical transmission lines.
However, the real find from the test was the prompt EMP, which was not anticipated. (See my post further down on that one.)
This test series (specifically, Starfish Prime) uncovered the electromagnetic pulse (EMP) effect, an unexpected side effect of nuclear explosions at altitude. The gamma rays from a high altitude burst hit atoms and thus eject electrons high in the atmosphere over a wide area, more or less simultaneously, and the current from the ejected electrons can cause a very wide-spread electromagnetic pulse, which can knock out power lines and electronics at great distances (> 1000 km).
So, I guess we can call Allen the father of the EMP, although I am not sure he would have wanted the honor.
I know of large US companies that do not allow executives to take their laptops into China, as they assume that its contents will be read (at the border or elsewhere). So, they get a sanitized laptop for the trip. Sounds extreme, but there have been cases of industrial espionage in the past.
Hayabusa was not a failure, failure of the sample return or no. It returned a lot of information about a near Earth asteroid including (to me) the very fundamental result that the regolith appears to be well mixed. This means that the asteroid is not just a lump of rubble but something is stirring material from inside to the surface and back again. This will prove very significant when we start doing engineering on asteroids (such as mining or setting up bases).
Traveling in deep space is tough. All of the countries that have done it have suffered through a pretty steep learning curve. Japan's space agency should be congratulated for pulling this off; I hope that the (undeserved) bad press doesn't make them shy from trying innovative missions such as Hayabusa in the future.
So, when are they going to apply this to the Voynich manuscript ?
We photographed many, many alien planets before this one: every time anyone pointed a camera at the sky, in fact. We've just not spotted any planets in those other images (yet).
Maybe (in a handful of all of the millions of images taken of astronomical objects), but I would doubt it. Exo-Planetary imagery is tough and is generally done of new systems in the IR (young planets are hot, and thus glow brighter). If by "photographed" you mean "an image with at least one pixel that could be recognized as an exo-planet if only we knew where to look," it's not likely that even the Hubble has captured any planets unawares. It's for sure not common.
The key word in the title is "confirmed." Readers may remember that there were 2 separate sets of planets photographed in papers published in 2008. Now, we are sure (not that there was much doubt) that one of them is truly orbiting its primary star.
From the original article
Suppose that Mr. Smith has two children, at least one of whom is a son. What is the probability both children are boys?
Intuition would suggest that the answer should be 1/2, since the sex of one child is independent of the sex of the other. And indeed, had he been told which child was a boy (say, the younger one), this reasoning would be sufficient. But since the boy could be either the younger or the older child, the analysis is more subtle. Devlin started by listing the children’s sexes in the order of their birth:
Boy, girl
Boy, boy
Girl, boy
Since one child is a boy, we know that girl, girl isn’t a possibility. Of the three approximately equally likely possibilities, one has two boys and two have a girl and a boy — so the probability of two boys is 1/3, not 1/2, Devlin concluded.
But this makes no sense whatsoever. For simplicity, I will assume that the human sex ratio is 1:1, and ignore the possibility of identical twins. I will also ignore the possibility of the "Monty Hall effect" - i.e., that there is other information that skews reporting of the first child. (Without this, anything can go. Suppose that I belong to a religion that believes that the birth of two boys in a row is deeply shameful and should never be mentioned. If you know that, saying that I have one boy make the probability of a girl 100%. Any other probability you might want is also possible, and so this has to be ruled out.)
To make the English clearer, suppose that I am on a beach with equal numbers of blue (B) and green (G) pebbles, and I pick two up, carefully noting the color of each.
So, an observer who just knows I have picked up two pebbles (but not the color of either) has the following probability table
BG - 25 %
BB - 25 %
GB - 25 %
GG - 25 %
Ok, I continue to walk along and meet up with the observer, and as I do so one pebble drops at random out of my bag. It is Blue (B). The observer sees this, and modifies his probability table as follows :
New probability = old probabiity x probability of having a Blue pebble fall out (renormalized to sum to unity, if necessary). This yields
BG - 25 %
BB - 50 %
GB - 25 %
GG - 0 %
So, the problem with the original "Birthday Problem" analysis is that, while there are indeed three choices, one with a second boy, and two with a girl, the probability of these choices are not equal ! With the correct probabilities, the chance that the second child is a boy is 50%
I would argue that, in the universe of these problems (where you are not supposed to need additional, unstated, information beyond basic things like people want to minimize jail time and maximize revenue), this is the correct analysis of the original "Birthday Problem," and the one presented in the original article is wrong.
The original "Tuesday Birthday Problem" analysis is likewise wrong, in the same fashion.
Here is my reasoning. First, the boy could be one of an identical twin, in which case the other child is certainly a boy (maybe born on Tuesday, maybe not). The
probability of that is 0.004 (0.4%), according to this.
Of course, with probability 1.000 - 0.004 = 0.996 the children are not identical twins, in which case the probability of a boy is 0.512195 (the human live birth sex ratio).
So, the probability of a second boy is
0.004 + ( 0.996 * 0.512195) = 0.514146
Whatever the sex ratio, you gain 1/2 of the probability of identical twins if the other child is a boy (and you lose that amount if the other child is a girl, for the same reason).
I am assuming in all of this live births (i.e., that the children were not stillborn and did not miscarry), but the statement is "I have" not "I had," implying live births.
The easiest way to find oil in gravity maps from what I understand is to look for salt domes (big bubbles of salt), which are much less dense than the surrounding rock.
The big low in the Indian ocean is thought to be related to subduction and may even be a "wake" from the recent passage of the Indian subcontinent as the plate drifted North. I don't think it is a huge salt dome.
Grace and GOCE are completely different experiments, which measure different (but related) things about the Earth's gravity field. Grace tracks the motions of a pair of satellites, which GOCE uses pairs of accelerometers. Different data types, different measurement errors, different types of systematic errors. I think it is well worth running both experiments.
The data is a model of what sea level would be, for a completely water covered Earth, assuming that the oceans had uniform density and no currents, minus the mean sea level. This sounds complicated, but it is pretty easy to calculate, assuming you have the gravity data.
There is a fascinating deep area in the Indian ocean (-100M) and a high area near Iceland (+80M), proving conclusively that our world is not homogeneous in terms of density (or practically any other measure). Does anyone know whether these anomalies correspond to known geographic phenomena? Deposits of heavy metals perhaps, or hotspots where the mantle is thinner? I know little about geodetic stuff, but I'm curious about the reasons for wrinkles in the data set."
Something that is maybe not so clear from the discussion in TOA, this is an accelerometer mission, and thus reveals a high pass filtering (AKA high-harmonic geoid signatures) of the gravity field. I am not sure if the geoid map in the BBC article is entirely from GOCE data, or if it has other data filling in the low spatial frequencies - it looks pretty similar to older geoid maps.
You might want to read this paper, which points out that
"The interpretation of GOCE geoid and gravity anomaly maps in terms of structure and dynamics of the Earth is
neither simple nor straightforward."
You can see things like typography, sea-mounts (modern gravity data is very good at detecting these), mountain ranges (these are like icebergs, made of lighter material with deep roots, and so are typically actually geoid lows), subduction zones, etc. Since what's going on may be determined by mass / density changes in the deep mantle, figuring out what the observed structures mean can be tough.
However, the scientific interest in these gravity data largely centers around changes in gravity, and many of these are more straightforward. Among the signatures of interest are ocean current changes (might change the dynamic sea level by 10 cm), ice formation and melting (for example, of the Greenland ice sheet), and the global water balance on land (if it rains, it changes the mass loading of the ground, and thus the geoid). Data such as these, and the data from GRACE, are becoming more and more important in the study of global geodynamics. The literally show what's happening on the ground, in basically real time.
I have (quickly) read the paper. The author does a stichometric analysis and concludes that there is a mathematical structure in the texts (which seems reasonably solid) and that (as Aristotle said), Plato was thus a Pythagorean (they were big on numerical mysticism). I would regard that as a "definite maybe." And that's pretty much it. To go from that to that he "anticipated the Scientific Revolution 2,000 years before Isaac Newton" is, IMHO, a stretch.