Ahem. I know better than to feed these, but I thought I might interject an observation here. I live in the middle of the Willamette Valley in Oregon(about 1500 km from the nearest Mexican border). During the harvest season, the population in the region swells noticably from the influx of immigrant workers from Mexico. They are here working long-hour, manual-labor jobs that the typical US citizen wouldn't even consider, and at a pay rate that would be criminal except that the workers aren't actually citizens here. Evidently, some of your countrymen seem to think that this kind of life is better than what they left behind. I'm told that when those who are here illegally get caught and are deported, they come right back across the border for more of the same. And you want me to believe there is nothing my country has that someone in your's may want?
Please don't mistake my message here. If you're happy where you are and doing what you're doing, why should you want anything else?
Personally, I wish that the US govt would do more to examine what it is doing and stop going out of its way to make new enemies. Believe it or not, I'm not alone in this wish... maybe someday we all can get along...
On my own personal projects, I get to choose something I'm interested in.
So, now my #1 concern when looking for a new job is, "am I interested in what I will be programming?"
Not even this necessarily prevents burnout. I'm working on finishing my MS degree in computer science with a non-thesis project. A year ago, when I started, it seemed very cool. Six months ago, when I was up to my scalp in debugging all sorts of nasty, subtle flaws, I started burning out. Three months ago, I started to wonder what kinds of little kulges I could "slip in" to make the program look like what it was supposed to do, that way I could simply be done, get my degree and go. Fortunately, I have stubborn streak several kilometers wide, which, when mixed with an almost-overzealous work ethic, prevented me from doing so. The project is nearly done and appears to be working fine... there is nothing like reaching the end of a project to rekindle interest in it!:-)
If you do the integration over the surface of a sphere, with all of the associated trignometric adjustments, you'll find that it's the same result as integrating over a disk of the same radius without any trig to worry about. This really is valid, standard practice.
And if you go ahead and do the integration over a spherical surface, you'll find the same result as if you'd simply integrated across a disk of the same radius.
Re:Doesn't the earth receive more?
on
Lunar Power
·
· Score: 1
Actually, about 10% is the number you're looking for. A quick, back of the envelope-type calculation shows that the figure for the moon can be roughly obtained by integrating the Solar constant for the Earth(after all, the moon spends half its time on one side of the Earth's orbit, averaging out any variation) of the surface area of the disk of the moon. Performing the same calculation for the Earth shows that the Earth recieves 12-13 times as much power(above the atmosphere) as the moon. So, if we can extract 10% of this, we can get as much power as we could get from the entire surface of the moon. Sources for my figure are at NASA JPL.
In Oregon, the education budget is taken primarily from property tax, although, I believe that there are "project" funds taken from the state lottery. I'm not sure, but I think "project"s are things that are one-time expenditures - like a school building that needs a new wing built, or a highway that needs repaving - that sort of thing. Of course, there's a whole bureaucratic process to go through to get lottery funding of a project....
This may be a little off-topic, but you haven't actually been to Oregon, have you? Sure there are people here who place value on education and schools, but there is a lot of people who don't(retired or otherwise don't have children). They may be a vocal minority rather than an actual majority, but they have been working hard to take our school system apart. In 1990 and 1995 the populace passed laws that cut and severely limited the state's ablility to collect property taxes - in Oregon , property tax funds public education. This year, in order to balance the overall state budget, the legislature is proposed "borrowing" money from the money previously set aside for education - as if the schools have no need of it right now. As a product of the Oregon public school system, I'm surprised that I was able to get a decent education in this environment.
I'm not sure you'll find many people rushing to the schools' aid for the sake of the schools themselves, although spending the extra tax $$$ on the licenses may open some eyes...
For anyone who's interested, you can find out about Dave Arneson's latest enevours at his webpage. I'm personally interested in his rewriting(for the d20 rules) of his Blackmoor campaign....
The most straight-forward solution to the data loss problem is to design the software to maintain its own restart data. I've spent about a year working on an atmosperic simulation that typically takes several days to run. We wrote the sim program to dump its current state every hour or so, that way in the event of catastrophy(power outage, OS crash, whatever), the most we'd lose is an hour's worth of computation. Of course, this requires that you have enough access to the innards of the program to do this...
So, hypothetically, since these are all custom made, we could string a bunch of them together to build a complete system much smaller than your average microchip?
Only problem is you might loose your PC in the laundry or accidentally throw it out with your pocket lint...:-)
I've got a buddy who's working on a similar concept for cellphones: a GPS receiver/transmitter that will allow the user to, for example, locate the nearest hotel and(eventually) provide driving directions to get there. Unfortunately, the electronic database of hotels isn't anywhere close to being up to date. If there isn't an up to date hotel database, is there an up to date pub database? Personally, I hope so... but I have my doubts...
Wasn't aerobraking used for one of the Jupiter probes? I don't think is was Galileo, but I seem to recall that it had been used on a previous mission...
The idea here is to use solar power - which is available so abundantly that it doesn't matter whether or not the process is very efficient. Simply use the (nearly) free solar power to convert seawater to hydrogen, then use the hydrogen from there. It's more a matter of economics than thermodynamics...
I'm not all that familiar with the TiO2 catalyst the article mentions. Does this work? It seems to me that simply focusing a laser on a body of water - no matter how many megawatts are involved - would have one result: liquid water boiled into steam. Am I missing something here?
I'm also curious about the wavelength of the orbital laser. I don't have a reference in front of me, but as I recall, the primary "window" through the atmosphere is in the visible and IR wavelengths... How much diffraction and reflection of the laser light will there be? I wouldn't want to be on the airliner that gets hit by part of the beam that gets reflected off an ice crystal: 1% of 10 megawatts is still 100 kilowatts - no small amount of power!
If these difficulties can be adequately addressed, it sounds like a great idea to me!
Ummm.... I may be wrong, but I thought that gravity was able to attract photons. It is an effect of General Relativity, not Newtonian mechanics(which requires gravitational attraction to be between objects having mass). I think this is the principle for the "gravitational lens" that astronomers use to help detect faint stars and, I guess, planets...
-> Ah... So even if it's not outright bullshit, it's too slow to use?
I think this would have to be true. My limited understanding of compression is this: the amount of information in a data file(of any type) must be conserved. A good measure for the amount of data might be the number of bits. In the uncompressed file, each bit is unique and contributes to the whole of the information contained there. In previous posts, it has been stated that the simplest compression routines simply count the number of repetitions of certain bits(eg, 62 1-bits followed by 17 0-bits followed by... etc). But how does the computer represent that count? Normally as a binary number - that is, if you give each bits its own level of significance(increasing exponentially from the least significant bit up to the most significant bit), then a large count can be reduced to a smaller number of bits(so the count of 62 bits would be reduced to 00111110). So, now that I've reduced 62 bits of data to 8 bits, where is the leftover data? It is found in the significance placed on the ordering of the bit - that is, I've constructed a framework where each bit represents some meaning in addition to itself. Without that framework, my string of 8 bits has no more meaning than two 0s followed by five 1s followed by one 0.
If my understanding of data compression is correct, then the entire art of compression centers around finding constructs and patterns that allow a given dataset to be represented in the most compact form. Unfortunately, what that means is that the extra information has to be bound up in the scheme and computing power will be required to extract the meaningful data... especially with 100:1 compression.
One last word to all the naysayers out there: There's nothing wrong with being skeptical, but let's keep in mind that many of most significant discoveries in history have been made against the prevailing theory of how the world works. Let's not reject it out of hand simply because it violates our sensibilities...
As I understand it, Narsil/Anduril is a sword of extra ordinary make - magic if you will. Not only was it made by the finest craftsmen with the best material(why use something as weak as steel or titanium?), it is also enhanced with the strongest enchantments elves and men could come up with at it's forging - in fact, only a creature as mighty as Sauron could have borken the sword.
WARNING, MINOR SPOILERS AND MAJOR SPECULATION TO FOLLOW:
What I've been wondering about, since I've seen the film, is this: In the book, Narsil is reforged as Anduril before the Fellowship leaves Rivendell, but in the movie, Aragorn is clearly using the same sword all the way through the movie. Given that the sword is a great artifact as well as the sword of the King of Gondor, we must assume that it has to come to Aragorn at some point in the series. My guess is that Arwen(who is clearly one of the few actually encouraging Aragorn to take back the kingdom he's inherited) will either have it reforged - or maybe she'll reforge it herself, and have it sent to Aragorn after the battle of Helm's Deep. In the book, Arwen sent the King's standard, but I think that PJ is counting on the sword having more significance at that point in the story...
If I understand the Nature summary correctly, the patterned fluid is analagous to a Mott insulator... I think what is considered to be new is the state that produces this effect - the article is careful to state that it is not a heat related phenomena, but one driven by the Heisenberg principle - that is the optical system doesn't heat the fluid up to produce a standing wave - the wave is a result of a more fundamental principle....
Of course, it has been a long time since I slept through quantum mechanics, so I've probably missed just as much, if not more than you....:-)
I remember reading the short story when I was in high school and thought to myself when I read it that it could make a cool movie. I felt the same excitement all over again when I saw a preview on a rented movie several years ago. Every once in a while I wondered if I'd missed it(college life can do that to you)... it's nice to see it finally make it to the screen! I know I'll go out to see it when it reaches the theaters here.
I was merely quoting the primary source I'm working from. I have to get mine working properly before I have any objective data of my own:(
You're right, of course. In fact, the "Efficent" part of the algorithm has to do with the event selection(use a balanced tree and event selection becomes a log N operation). With large data sets, this is extremely important. It won't be until I add better physics that the computational aspect will be seen all that much...
The primary reason I didn't use Fortran 90/95(so I could compare the run times of the resulting programs) is that I don't have access to a good compiler.
Hmmm... before we start arguing P vs NP-complete problems, how about some actual data? If Fortran produced code twice as fast as C, the whole "C vs Fortan" religeous war wouldn't exist. I am using C for my current project, an event-driven har particle simulation, because the paper in which the algorithm I'm using was published stated that the program produced from the C compiler run about 10% faster than the equivalent Fortran program(Marin, Risso, Cordero; Efficient Algorithms for Many-Body Hard Particle Molecular Dynamics; Journal of Computational Physics, 1993, vol 109, pgs 306-317).
This doesn't make the rest of what you say invalid - in fact I agree with most of the rest of what you said, including the advice to make use of large-grained objects. What makes OO languages important in large scale software engineering is that they tend to enforce good programming style(an object is really a logical ordering of high cohesion procedures and data). Good programming style can be used to great benefit in any language, but many languages allow a large number of horrible abuses - C is the poster child for abusable languages. I think this why OO elements are finding their way into most modern languages: C evolved into C++ and objective C and even Fortran 95 has OO capabilities.
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Ahem. I know better than to feed these, but I thought I might interject an observation here. I live in the middle of the Willamette Valley in Oregon(about 1500 km from the nearest Mexican border). During the harvest season, the population in the region swells noticably from the influx of immigrant workers from Mexico. They are here working long-hour, manual-labor jobs that the typical US citizen wouldn't even consider, and at a pay rate that would be criminal except that the workers aren't actually citizens here. Evidently, some of your countrymen seem to think that this kind of life is better than what they left behind. I'm told that when those who are here illegally get caught and are deported, they come right back across the border for more of the same. And you want me to believe there is nothing my country has that someone in your's may want?
Please don't mistake my message here. If you're happy where you are and doing what you're doing, why should you want anything else?
Personally, I wish that the US govt would do more to examine what it is doing and stop going out of its way to make new enemies. Believe it or not, I'm not alone in this wish... maybe someday we all can get along...
Not even this necessarily prevents burnout. I'm working on finishing my MS degree in computer science with a non-thesis project. A year ago, when I started, it seemed very cool. Six months ago, when I was up to my scalp in debugging all sorts of nasty, subtle flaws, I started burning out. Three months ago, I started to wonder what kinds of little kulges I could "slip in" to make the program look like what it was supposed to do, that way I could simply be done, get my degree and go. Fortunately, I have stubborn streak several kilometers wide, which, when mixed with an almost-overzealous work ethic, prevented me from doing so. The project is nearly done and appears to be working fine... there is nothing like reaching the end of a project to rekindle interest in it! :-)
If you do the integration over the surface of a sphere, with all of the associated trignometric adjustments, you'll find that it's the same result as integrating over a disk of the same radius without any trig to worry about. This really is valid, standard practice.
And if you go ahead and do the integration over a spherical surface, you'll find the same result as if you'd simply integrated across a disk of the same radius.
Actually, about 10% is the number you're looking for. A quick, back of the envelope-type calculation shows that the figure for the moon can be roughly obtained by integrating the Solar constant for the Earth(after all, the moon spends half its time on one side of the Earth's orbit, averaging out any variation) of the surface area of the disk of the moon. Performing the same calculation for the Earth shows that the Earth recieves 12-13 times as much power(above the atmosphere) as the moon. So, if we can extract 10% of this, we can get as much power as we could get from the entire surface of the moon. Sources for my figure are at NASA JPL.
"You are bad. We are good. Your badness will be your downfall; our goodness will be our triumph. Bad bad good bad good bad bad... good"
to which Black Helmet Man replies something to the effect of "Your will is strong, as is your silly gibberish".
Sorry, it's better in the context of the film...
In Oregon, the education budget is taken primarily from property tax, although, I believe that there are "project" funds taken from the state lottery. I'm not sure, but I think "project"s are things that are one-time expenditures - like a school building that needs a new wing built, or a highway that needs repaving - that sort of thing. Of course, there's a whole bureaucratic process to go through to get lottery funding of a project....
I'm not sure you'll find many people rushing to the schools' aid for the sake of the schools themselves, although spending the extra tax $$$ on the licenses may open some eyes...
For anyone who's interested, you can find out about Dave Arneson's latest enevours at his webpage. I'm personally interested in his rewriting(for the d20 rules) of his Blackmoor campaign....
The most straight-forward solution to the data loss problem is to design the software to maintain its own restart data. I've spent about a year working on an atmosperic simulation that typically takes several days to run. We wrote the sim program to dump its current state every hour or so, that way in the event of catastrophy(power outage, OS crash, whatever), the most we'd lose is an hour's worth of computation. Of course, this requires that you have enough access to the innards of the program to do this...
So, hypothetically, since these are all custom made, we could string a bunch of them together to build a complete system much smaller than your average microchip? :-)
Only problem is you might loose your PC in the laundry or accidentally throw it out with your pocket lint...
I've got a buddy who's working on a similar concept for cellphones: a GPS receiver/transmitter that will allow the user to, for example, locate the nearest hotel and(eventually) provide driving directions to get there. Unfortunately, the electronic database of hotels isn't anywhere close to being up to date. If there isn't an up to date hotel database, is there an up to date pub database? Personally, I hope so... but I have my doubts...
Wasn't aerobraking used for one of the Jupiter probes? I don't think is was Galileo, but I seem to recall that it had been used on a previous mission...
The idea here is to use solar power - which is available so abundantly that it doesn't matter whether or not the process is very efficient. Simply use the (nearly) free solar power to convert seawater to hydrogen, then use the hydrogen from there. It's more a matter of economics than thermodynamics...
I'm also curious about the wavelength of the orbital laser. I don't have a reference in front of me, but as I recall, the primary "window" through the atmosphere is in the visible and IR wavelengths... How much diffraction and reflection of the laser light will there be? I wouldn't want to be on the airliner that gets hit by part of the beam that gets reflected off an ice crystal: 1% of 10 megawatts is still 100 kilowatts - no small amount of power!
If these difficulties can be adequately addressed, it sounds like a great idea to me!
Ummm.... I may be wrong, but I thought that gravity was able to attract photons. It is an effect of General Relativity, not Newtonian mechanics(which requires gravitational attraction to be between objects having mass). I think this is the principle for the "gravitational lens" that astronomers use to help detect faint stars and, I guess, planets...
I think this would have to be true. My limited understanding of compression is this: the amount of information in a data file(of any type) must be conserved. A good measure for the amount of data might be the number of bits. In the uncompressed file, each bit is unique and contributes to the whole of the information contained there. In previous posts, it has been stated that the simplest compression routines simply count the number of repetitions of certain bits(eg, 62 1-bits followed by 17 0-bits followed by... etc). But how does the computer represent that count? Normally as a binary number - that is, if you give each bits its own level of significance(increasing exponentially from the least significant bit up to the most significant bit), then a large count can be reduced to a smaller number of bits(so the count of 62 bits would be reduced to 00111110). So, now that I've reduced 62 bits of data to 8 bits, where is the leftover data? It is found in the significance placed on the ordering of the bit - that is, I've constructed a framework where each bit represents some meaning in addition to itself. Without that framework, my string of 8 bits has no more meaning than two 0s followed by five 1s followed by one 0.
If my understanding of data compression is correct, then the entire art of compression centers around finding constructs and patterns that allow a given dataset to be represented in the most compact form. Unfortunately, what that means is that the extra information has to be bound up in the scheme and computing power will be required to extract the meaningful data... especially with 100:1 compression.
One last word to all the naysayers out there:
There's nothing wrong with being skeptical, but let's keep in mind that many of most significant discoveries in history have been made against the prevailing theory of how the world works. Let's not reject it out of hand simply because it violates our sensibilities...
WARNING, MINOR SPOILERS AND MAJOR SPECULATION TO FOLLOW:
What I've been wondering about, since I've seen the film, is this: In the book, Narsil is reforged as Anduril before the Fellowship leaves Rivendell, but in the movie, Aragorn is clearly using the same sword all the way through the movie. Given that the sword is a great artifact as well as the sword of the King of Gondor, we must assume that it has to come to Aragorn at some point in the series. My guess is that Arwen(who is clearly one of the few actually encouraging Aragorn to take back the kingdom he's inherited) will either have it reforged - or maybe she'll reforge it herself, and have it sent to Aragorn after the battle of Helm's Deep. In the book, Arwen sent the King's standard, but I think that PJ is counting on the sword having more significance at that point in the story...
Don't forget to bring some popcorn.
:)
Of course, it has been a long time since I slept through quantum mechanics, so I've probably missed just as much, if not more than you.... :-)
I remember reading the short story when I was in high school and thought to myself when I read it that it could make a cool movie. I felt the same excitement all over again when I saw a preview on a rented movie several years ago. Every once in a while I wondered if I'd missed it(college life can do that to you)... it's nice to see it finally make it to the screen! I know I'll go out to see it when it reaches the theaters here.
I was merely quoting the primary source I'm working from. I have to get mine working properly before I have any objective data of my own :(
You're right, of course. In fact, the "Efficent" part of the algorithm has to do with the event selection(use a balanced tree and event selection becomes a log N operation). With large data sets, this is extremely important. It won't be until I add better physics that the computational aspect will be seen all that much...
The primary reason I didn't use Fortran 90/95(so I could compare the run times of the resulting programs) is that I don't have access to a good compiler.
Hmmm... before we start arguing P vs NP-complete problems, how about some actual data? If Fortran produced code twice as fast as C, the whole "C vs Fortan" religeous war wouldn't exist. I am using C for my current project, an event-driven har particle simulation, because the paper in which the algorithm I'm using was published stated that the program produced from the C compiler run about 10% faster than the equivalent Fortran program(Marin, Risso, Cordero; Efficient Algorithms for Many-Body Hard Particle Molecular Dynamics; Journal of Computational Physics, 1993, vol 109, pgs 306-317). This doesn't make the rest of what you say invalid - in fact I agree with most of the rest of what you said, including the advice to make use of large-grained objects. What makes OO languages important in large scale software engineering is that they tend to enforce good programming style(an object is really a logical ordering of high cohesion procedures and data). Good programming style can be used to great benefit in any language, but many languages allow a large number of horrible abuses - C is the poster child for abusable languages. I think this why OO elements are finding their way into most modern languages: C evolved into C++ and objective C and even Fortran 95 has OO capabilities.