"You're standing on the surface of the Earth. You walk one mile south, one mile west, and one mile north. You end up exactly where you started. Where are you?"
Other posters have pointed out that "Where are you?" is ambiguous and could mean a Simon says sort of answer like "I'm in your office, Mr. Musk." And also that it could be taken to mean relative to a Sun-centered coordinate system. This latter requires waiting N years to return to the same part of the Earth's orbit.
Once one notices that no time limit is required you get many more solutions by allowing for the polar motion over some period of time: http://en.wikipedia.org/wiki/P... - that is, the pole isn't in the same place at the end as at the beginning.
Then there's the notion of repeating the exercise at the north and south magnetic poles (and perhaps geomagnetic). But there is also no explicit constraint that south, west and north are all interpreted the same - they need not all be geographic or all magnetic. In that case there are families of solutions near each of the four poles that interpret the initial motion one way and the final mile the other.
And then the magnetic poles wander much more rapidly (several miles per year) than the geographic poles and over much more than the mile allowed (http://en.wikipedia.org/wiki/South_Magnetic_Pole), so you can put constraints on the time period allowed for the exercise while exploring solutions covering motions over a few weeks.
Mars exploration splits into two eras, the cold war competition between the U.S. and Soviets - which the U.S. won hands-down, Yay Mariner! Yay Viking! - and the past couple of decades with the U.S. and other countries collaborating in various combinations.
During the cold war the U.S. had a track record of 8 successful missions versus 2 launch failures. During the recent couple of decades we've had 9 successes versus 3 diverse spacecraft failures. And many of those successes have been far beyond mission profiles. So the NASA Mars team is about 17 wins against 5 losses. This would be regarded as stunningly successful in any sport.
The Soviets in the early days had many launch failures that can't really be charged to the Mars missions themselves - and were about the reverse of the U.S. cold war ratio for those that did get to Mars. It was still a remarkable achievement for them to place any one of those missions in orbit.
There have also been about a half dozen non-NASA Mars missions during the past two decades. Two Russian missions unfortunately continued the trend of never leaving LEO. And now India is one-for-one. May they keep it up! Europe is one-for-two and Japan is zero-for-one. Talk about small number statistics, but that's 2 wins / 2 losses. Quite respectable. One hopes other nations join the fun.
In the aggregate this is a remarkable tally of successful missions considering Mars is never closer than 50 million kilometers or so. Anybody know the corresponding statistics for missions in LEO?
For those who think the only problem is bad programming, see Leslie Lamport's analysis:
http://research.microsoft.com/...
Some race conditions are built into the real world.
Whatever this guy and Thomas Friedmann (and alas! Terry Pratchett) say, the world is not flat. Algebraic equations of degree higher than linear (and even - gasp - other than polynomials entirely) are needed to describe how it works. Algebra is the bare minimum to comprehend how functions work. It is telling that TFA doesn't even mention differential equations - the real basecode of the universe. A grounding in algebra provides the most basic of tools to understand graphical representations of a dynamic multivariate world, even without calculus.
That a political scientist would emphasize "lies, damn lies, and statistics" as the pinnacle of mathematics is unsurprising.
It depends on the figure of merit and on the measure of central tendency being applied to it. "Average" can mean different things. If the distribution is skewed, the arithmetic mean will always lie to one side or the other of the median.
Stuart Smalley seems the poster child for Dunning-Kruger and related effects.
Astronomical data are background limited. The noise is as interesting as the signal, and many sources lie beneath the noise and are only visible through coadding. The gain and read-noise of LSST's detectors will be tuned similarly to other astronomical cameras because these parameters are governed by the experimental design.
Lossless Rice compression should be around R of 2-2.5 (http://arxiv.org/pdf/0903.2140.pdf) with lossy compression of reduced data products falling between R of 3 to 5 depending on the quantization selected (http://arxiv.org/pdf/1007.1179.pdf).
There will be no delta frame advantage since the compression is governed entirely by the noise (i.e., entropy) due to the sparse signal in astronomical data and the noise is a combination of gaussian and poisson (shot noise) sources that varies from exposure to exposure.
In fact, a key goal of the project is precisely to look for differences between each frame and a baseline static sky so the differences must be preserved in great detail.
A career in the sciences is far less likely to be touched by fraud than more commercial endeavors. "Follow the money" as they say. Each discipline is its own community, however, and the level of political infighting, the need to struggle for funding, the publication pressures, etc, vary greatly. External pressures are different, too, but condensed matter physics is about as far from the front lines of the culture war as one can get:-)
I do wonder what mythical past the recent critics of science (and of academia in general) are comparing us with. Government funding has always been in the mix. Corporate funding has always come with strings attached. Read Neal Stephenson's Baroque Cycle to get a sense for the underlying drama of research as a creative exercise.
A good bit of luck is needed to follow the narrow path to tenure. (I stepped off long ago.) A good bit of luck is needed to bubble to the "top" of any organization of any type. The difference with the sciences is that there are innumerable interesting detours and niches along the way. Having a graduate degree in a STEM field is an advantage for pursuing many future options. And the journey has been a hell of a lot of fun!
Ultimately the question becomes "compared to what?" How will you put food on the table if you forgo grad school? And is a seat at a smaller table enough for you?
Blame the WSJ for the tropes here about physicists and "culturomics". The lead author of the linked paper is an economist. The WSJ article also mingles information from other publications. On the other hand, Steven Pinker has (rather persuasively) argued for a physical model underlying the structure of language (and not just in English): http://stevenpinker.com/publications/stuff-thought
I read through the 4-pointers and didn't see a citation to the original paper. This appears to be it:
http://maxwellsci.com/print/crjss/v2-255-261.pdf
It has precious little to do with any of the grandiose claims being attributed to it. TFA and the scores of echoed "See? I told you democracy was a scam!" articles are aggressively misconstruing the meaning of this. The paper is a couple of years old and the author appears to have no special expertise in this field.
It's a tradition on slashdot to not read the article, but has anybody of any political persuasion here actually clicked the link? It's a piece of crap designed to be echoed around the internet. So far I've been unable to locate the cited research from either this article or in any of its echoes or by searching directly. The word "smart" is something added to create heat, the phrase used is "leadership skills", and there is no indication how such skills are gauged in either the simulated voters or the simulated candidates. Nor any mention that the voters only get to choose between two starkly different candidates - this is a rather binary decision to simulate. It is insipid to blame the voters for the candidates produced by the major parties.
This isn't about an imposed classification, it is about a family tree. Crocodiles are more closely related to birds than either are to snakes. Snakes are more closely related to birds than either are to turtles.
If you're going to do this, run it in the opposite direction as a geothermal (well, selenothermal) heat pump. Yes, yes - still need to establish a cold sink. But the value of all these ideas depends on the detailed engineering, not on slashdot opinion mongering.
It's naive to consider either class of software as being sufficient, or either kind of programming to be superior. Like most problems there is a strong management component to assigning resources to each in appropriate scales.
A computer scientist/software engineer delivered a well-phrased summation of half of this discussion during a 5-minute talk at a recent lightning software session at a science meeting. (Note that there are rarely science sessions at software meetings.) A domain scientist/software engineer then delivered a well-phrased summation of the other half of this discussion. Both were right and both were wrong.
My five minutes? Pointing out that the real issue was that management rarely supplies sufficient resources to coherently accomplish software projects of any type. Typically projects are underscoped by a factor of three or more, whether the particular project is to build a robot or an exoskeleton. This is true whatever software process is followed, but in terms of the Mythical Man Month, it's like omitting the nurses and anesthesiologist from the surgical team.
supports a very straightforward remapping onto a dome through multiple projectors (don't know about the military grade nonsense). There's a calibration screen that handles all the geometry. Just need some baffling to minimize the overlap between projectors.
Navigating through the Sloan galaxies is very impressive on a planetarium dome. WWT also displays a half million objects in the asteroid belt, Kuiper belt, etc in real-time (or in accelerated motion) using that space-age GPU technology. (Of course, "real-time" is another overused buzzword.)
Many applications in astronomy - and likely in other fields - explicitly do not apply a DUT1 (or other EOP) correction because they assume that UTC is close enough to UT.
Many of these will have to start applying a DUT1 correction because UTC will no longer provide Universal Time.
The ITU-R proposal also is to stop issuing the DUT1 offset time signals. Some systems currently rely on non-standardized access to ad hoc resources such as you describe. Someone or some community will have to standardize these procedures and deploy battle-hardened infrastructure suitable for the increased load.
No engineering plan exists for work related to this infrastructure. The assumption is that it will just magically happen. Services will be designed, deployed, funded, operated, maintained - and applications will be rewritten to make use of them. Who will do this?
That you (or others) can't conceive of requirements for mean solar time implicit in various nooks and crannies of civil timekeeping does not mean that such requirements don't exist. A coherent systems engineering plan is the way to reveal such requirements.
One might think that those tasked with guiding missiles might prefer to have their engineers take a look at this before it is voted upon.
Maybe this change is a Y2K style jobs program. Nah, too few types of code are affected. It's not like my bank needs UT1 or barycentric dynamical time to the microsecond.
Y2K was a non-millennial event precisely because squadrons of crack programmers were deployed to fight the good fight. A Y2K inventory such as: http://iraf.noao.edu/projects/y2k/y2kplan.html, was a relatively straightforward exercise in pattern matching, but still required the examination of the entire codebase.
A similar UTC-clean inventory will be needed against a similarly broad codebase. It will not be a simple exercise in pattern matching. The assumption has been that whole industries and communities can ignore the whole thing. This assumption results from viewing the issue as being about ceasing leap seconds.
Rather, like the curious incident of the dog that didn't bark, the absence of leap seconds has broader implications, namely UTC will no longer be a type of universal time. Rather than simplifying civil timekeeping, suddenly two types of time must become explicit in the source and libraries of diverse systems that previously could assume they were the same thing.
Banks may not need "UT1 or barycentric dynamical time to the microsecond". But the error will accumulate six orders of magnitude larger than that annually, and many of the systems funded by the banks - air, land and sea transportation, GIS, communications, logistics in addition to science and tech - may certainly care.
The point is - nobody has looked. This is Y2K under an invisibility cloak.
Slashdot Mirror
...and different Geodetic datums ...and continental drift
There are other ways of looking at the problem:
"You're standing on the surface of the Earth. You walk one mile south, one mile west, and one mile north. You end up exactly where you started. Where are you?"
Other posters have pointed out that "Where are you?" is ambiguous and could mean a Simon says sort of answer like "I'm in your office, Mr. Musk." And also that it could be taken to mean relative to a Sun-centered coordinate system. This latter requires waiting N years to return to the same part of the Earth's orbit.
Once one notices that no time limit is required you get many more solutions by allowing for the polar motion over some period of time: http://en.wikipedia.org/wiki/P... - that is, the pole isn't in the same place at the end as at the beginning.
Then there's the notion of repeating the exercise at the north and south magnetic poles (and perhaps geomagnetic). But there is also no explicit constraint that south, west and north are all interpreted the same - they need not all be geographic or all magnetic. In that case there are families of solutions near each of the four poles that interpret the initial motion one way and the final mile the other.
And then the magnetic poles wander much more rapidly (several miles per year) than the geographic poles and over much more than the mile allowed (http://en.wikipedia.org/wiki/South_Magnetic_Pole), so you can put constraints on the time period allowed for the exercise while exploring solutions covering motions over a few weeks.
It is not true that "there have been many, many, many more attempts at Mars than missions that actually got there", see:
http://en.wikipedia.org/wiki/L...
Mars exploration splits into two eras, the cold war competition between the U.S. and Soviets - which the U.S. won hands-down, Yay Mariner! Yay Viking! - and the past couple of decades with the U.S. and other countries collaborating in various combinations.
During the cold war the U.S. had a track record of 8 successful missions versus 2 launch failures. During the recent couple of decades we've had 9 successes versus 3 diverse spacecraft failures. And many of those successes have been far beyond mission profiles. So the NASA Mars team is about 17 wins against 5 losses. This would be regarded as stunningly successful in any sport.
The Soviets in the early days had many launch failures that can't really be charged to the Mars missions themselves - and were about the reverse of the U.S. cold war ratio for those that did get to Mars. It was still a remarkable achievement for them to place any one of those missions in orbit.
There have also been about a half dozen non-NASA Mars missions during the past two decades. Two Russian missions unfortunately continued the trend of never leaving LEO. And now India is one-for-one. May they keep it up! Europe is one-for-two and Japan is zero-for-one. Talk about small number statistics, but that's 2 wins / 2 losses. Quite respectable. One hopes other nations join the fun.
In the aggregate this is a remarkable tally of successful missions considering Mars is never closer than 50 million kilometers or so. Anybody know the corresponding statistics for missions in LEO?
For those who think the only problem is bad programming, see Leslie Lamport's analysis: http://research.microsoft.com/... Some race conditions are built into the real world.
Just as long as he doesn't get his hands on Galaxy Quest. Some things are sacred!
It would be all like "Give up! Surrender!"
"Political Scientist" is a colossal oxymoron.
Whatever this guy and Thomas Friedmann (and alas! Terry Pratchett) say, the world is not flat. Algebraic equations of degree higher than linear (and even - gasp - other than polynomials entirely) are needed to describe how it works. Algebra is the bare minimum to comprehend how functions work. It is telling that TFA doesn't even mention differential equations - the real basecode of the universe. A grounding in algebra provides the most basic of tools to understand graphical representations of a dynamic multivariate world, even without calculus.
That a political scientist would emphasize "lies, damn lies, and statistics" as the pinnacle of mathematics is unsurprising.
NASA Goddard is near Baltimore. They lost power in the storm and are operating under "Code Red": http://www.nasa.gov/centers/goddard/
Quite likely other misbehavior blamed on the leap second is actually the result of the storm (or like Pirate Bay, some unrelated crash).
How is it possible that 300 messages into the thread nobody has suggested starting (and ending) with Galaxy Quest?
It depends on the figure of merit and on the measure of central tendency being applied to it. "Average" can mean different things. If the distribution is skewed, the arithmetic mean will always lie to one side or the other of the median.
Stuart Smalley seems the poster child for Dunning-Kruger and related effects.
In related news, 46% of Americans believe themselves "above average".
Astronomical data are background limited. The noise is as interesting as the signal, and many sources lie beneath the noise and are only visible through coadding. The gain and read-noise of LSST's detectors will be tuned similarly to other astronomical cameras because these parameters are governed by the experimental design.
Lossless Rice compression should be around R of 2-2.5 (http://arxiv.org/pdf/0903.2140.pdf) with lossy compression of reduced data products falling between R of 3 to 5 depending on the quantization selected (http://arxiv.org/pdf/1007.1179.pdf).
There will be no delta frame advantage since the compression is governed entirely by the noise (i.e., entropy) due to the sparse signal in astronomical data and the noise is a combination of gaussian and poisson (shot noise) sources that varies from exposure to exposure.
In fact, a key goal of the project is precisely to look for differences between each frame and a baseline static sky so the differences must be preserved in great detail.
A career in the sciences is far less likely to be touched by fraud than more commercial endeavors. "Follow the money" as they say. Each discipline is its own community, however, and the level of political infighting, the need to struggle for funding, the publication pressures, etc, vary greatly. External pressures are different, too, but condensed matter physics is about as far from the front lines of the culture war as one can get :-)
I do wonder what mythical past the recent critics of science (and of academia in general) are comparing us with. Government funding has always been in the mix. Corporate funding has always come with strings attached. Read Neal Stephenson's Baroque Cycle to get a sense for the underlying drama of research as a creative exercise.
A good bit of luck is needed to follow the narrow path to tenure. (I stepped off long ago.) A good bit of luck is needed to bubble to the "top" of any organization of any type. The difference with the sciences is that there are innumerable interesting detours and niches along the way. Having a graduate degree in a STEM field is an advantage for pursuing many future options. And the journey has been a hell of a lot of fun!
Ultimately the question becomes "compared to what?" How will you put food on the table if you forgo grad school? And is a seat at a smaller table enough for you?
Blame the WSJ for the tropes here about physicists and "culturomics". The lead author of the linked paper is an economist. The WSJ article also mingles information from other publications. On the other hand, Steven Pinker has (rather persuasively) argued for a physical model underlying the structure of language (and not just in English): http://stevenpinker.com/publications/stuff-thought
I read through the 4-pointers and didn't see a citation to the original paper. This appears to be it: http://maxwellsci.com/print/crjss/v2-255-261.pdf It has precious little to do with any of the grandiose claims being attributed to it. TFA and the scores of echoed "See? I told you democracy was a scam!" articles are aggressively misconstruing the meaning of this. The paper is a couple of years old and the author appears to have no special expertise in this field.
It's a tradition on slashdot to not read the article, but has anybody of any political persuasion here actually clicked the link? It's a piece of crap designed to be echoed around the internet. So far I've been unable to locate the cited research from either this article or in any of its echoes or by searching directly. The word "smart" is something added to create heat, the phrase used is "leadership skills", and there is no indication how such skills are gauged in either the simulated voters or the simulated candidates. Nor any mention that the voters only get to choose between two starkly different candidates - this is a rather binary decision to simulate. It is insipid to blame the voters for the candidates produced by the major parties.
Pluto (the dog) was named after Pluto (the planet), not the other way around.
See (for instance):
http://www.amnh.org/exhibitions/hall_tour/spectrum/non_flash_index.html
This isn't about an imposed classification, it is about a family tree. Crocodiles are more closely related to birds than either are to snakes. Snakes are more closely related to birds than either are to turtles.
That is, these guys:
http://www.wolaver.org/animals/crocodile-plover.jpg
share a *much* more recent common ancestor than these two:
http://berkeley.edu/news/media/releases/2009/02/images/salamander-pgoebeil.jpg
and:
http://images3.wikia.nocookie.net/__cb20090630160120/uncyclopedia/images/2/2f/Geico-gecko.jpg
You are more closely related to a goldfish than the goldfish is to a shark:
http://rlv.zcache.com/goldfish_bowl_tshirt-p23514656184174989535jn_400.jpg
http://bit.ly/nknQ00
Some of these comments are isomorphic to this review of Richard Dawkin's history of your family tree:
http://creation.com/review-the-ancestors-tale-richard-dawkins
If you're going to do this, run it in the opposite direction as a geothermal (well, selenothermal) heat pump. Yes, yes - still need to establish a cold sink. But the value of all these ideas depends on the detailed engineering, not on slashdot opinion mongering.
A third thing you should know is that a vote will be taken in January 2012 to decouple UTC from GMT: http://catless.ncl.ac.uk/Risks/26.50.html#subj12
It's naive to consider either class of software as being sufficient, or either kind of programming to be superior. Like most problems there is a strong management component to assigning resources to each in appropriate scales.
A computer scientist/software engineer delivered a well-phrased summation of half of this discussion during a 5-minute talk at a recent lightning software session at a science meeting. (Note that there are rarely science sessions at software meetings.) A domain scientist/software engineer then delivered a well-phrased summation of the other half of this discussion. Both were right and both were wrong.
My five minutes? Pointing out that the real issue was that management rarely supplies sufficient resources to coherently accomplish software projects of any type. Typically projects are underscoped by a factor of three or more, whether the particular project is to build a robot or an exoskeleton. This is true whatever software process is followed, but in terms of the Mythical Man Month, it's like omitting the nurses and anesthesiologist from the surgical team.
See also: http://www.cis.udel.edu/~mills/ipin.html
Somebody mentioned wanting a planetarium at home. This is very doable. The current version of WorldWide Telescope:
http://www.worldwidetelescope.org/
supports a very straightforward remapping onto a dome through multiple projectors (don't know about the military grade nonsense). There's a calibration screen that handles all the geometry. Just need some baffling to minimize the overlap between projectors.
Navigating through the Sloan galaxies is very impressive on a planetarium dome. WWT also displays a half million objects in the asteroid belt, Kuiper belt, etc in real-time (or in accelerated motion) using that space-age GPU technology. (Of course, "real-time" is another overused buzzword.)
Supports Kinect controls for the game addicts.
Many applications in astronomy - and likely in other fields - explicitly do not apply a DUT1 (or other EOP) correction because they assume that UTC is close enough to UT.
Many of these will have to start applying a DUT1 correction because UTC will no longer provide Universal Time.
The ITU-R proposal also is to stop issuing the DUT1 offset time signals. Some systems currently rely on non-standardized access to ad hoc resources such as you describe. Someone or some community will have to standardize these procedures and deploy battle-hardened infrastructure suitable for the increased load.
No engineering plan exists for work related to this infrastructure. The assumption is that it will just magically happen. Services will be designed, deployed, funded, operated, maintained - and applications will be rewritten to make use of them. Who will do this?
That you (or others) can't conceive of requirements for mean solar time implicit in various nooks and crannies of civil timekeeping does not mean that such requirements don't exist. A coherent systems engineering plan is the way to reveal such requirements.
One might think that those tasked with guiding missiles might prefer to have their engineers take a look at this before it is voted upon.
Maybe this change is a Y2K style jobs program. Nah, too few types of code are affected. It's not like my bank needs UT1 or barycentric dynamical time to the microsecond.
Y2K was a non-millennial event precisely because squadrons of crack programmers were deployed to fight the good fight. A Y2K inventory such as: http://iraf.noao.edu/projects/y2k/y2kplan.html, was a relatively straightforward exercise in pattern matching, but still required the examination of the entire codebase.
A similar UTC-clean inventory will be needed against a similarly broad codebase. It will not be a simple exercise in pattern matching. The assumption has been that whole industries and communities can ignore the whole thing. This assumption results from viewing the issue as being about ceasing leap seconds.
Rather, like the curious incident of the dog that didn't bark, the absence of leap seconds has broader implications, namely UTC will no longer be a type of universal time. Rather than simplifying civil timekeeping, suddenly two types of time must become explicit in the source and libraries of diverse systems that previously could assume they were the same thing.
Banks may not need "UT1 or barycentric dynamical time to the microsecond". But the error will accumulate six orders of magnitude larger than that annually, and many of the systems funded by the banks - air, land and sea transportation, GIS, communications, logistics in addition to science and tech - may certainly care.
The point is - nobody has looked. This is Y2K under an invisibility cloak.