The general consensus is that people are being crybabies over the fact that they're being held to the contracts they signed, presumably of their own free will. No argument here. What baffles me is why people are even up in arms about upgrading - the differences between the iPhone 3G and 3GS are not really earth shattering - you can get a bigger capacity (up to 32 GB), autofocus camera, and the magnetometer... and that's about it. After all the hype over the new phone, I was pretty underwhelmed. Disclosure: I'm an iPhone 3g owner, and I'll be waiting until the next version to upgrade.
A study by Boeing [2] determined the primary cause of Airline hull loss accidents (worldwide commercial jet fleet), from 1996 through 2005, to be:
55%: Flight crew error
17%: Airplane
13%: Weather
...
Given that many, many airplanes were already at least partially computer controlled by '96, I think we can take this as evidence that it's not the fact that computers are so new that they're skewing the stats. For what it's worth, the stats from 1950 - present are similar.
So we don't have to depend on the engineers to get it right. We can (and do) check to see if they did.
To not provide that to the pilot is nothing short of hubris on the engineer's part, and people died because of it.
This is so wrong-headed it's hard to even wrap my head around. For one thing, no one has established the cause of the Air France crash. Also, statistics show that pilot error is by far the leading cause of aviation mishaps. Finally, as has been pointed out over and over, the Airbus AUTOMATICALLY provides an increasing amount of control to the pilot in the event of abnormal conditions.
The weak link in aviation (in terms of safety) is the human crew. Systems that mitigate this problem are a good thing.
... if airplane computer makers got to do their own accident investigations. In fact, they're done by the NTSB, which really doesn't give a shit about litigation. And in any case, do you think a ruling of "pilot error" vs. "computer malfunction" would magically prevent lawsuits?
First, the computers involved are very, very rigorously tested. It's not like someone took Microsoft Flight Simulator, ported it to the airplane's computer, and said "here you go"! Second, statistics show that the top causes of crashes are 1) pilot error, 2) mechanical failure and 3) weather. Computer error doesn't even make the list.
The pilot activated a system he shouldn't have, failed to disengage it, and instead fought against what the autopilot was trying to do. This is not an argument in favor of human control of the airplane.
I'd say "mod parent up", but he's already at +5. I am a safety engineer, and I can promise you that the leading cause of aircraft mishaps is, by far, pilot error. Machines don't get confused, they never show up hung over, their attention never wanders, and their behavior is deterministic and rigorously tested. It's the people who screw up. And as for "the right to ask"... well, I don't know about you, but no one has ever taped my mouth shut as I get on the airplane. I can already ask this question, and get off the airplane if I don't like the answer. It happens that this is a stupid question to ask.
Dude, we're talking K-12 textbooks here, not college. So:
which any student who found themselves pissed off in the book buyback line when offered a paltry sum of $10 for a book they paid $75 3 months ago.
There is no "book buyback line", and they didn't pay 75 bucks at the beginning of the semester. They got it issued to them, and they'll turn it back in at the end of the course. What's more, the state of California is a seriously big textbook buyer, and they can no doubt get good terms from publishers based on the enormous amount of business they'd be bringing. The question is purely whether, all things considered, it's cheaper for the state to provide a cheap netbook (which they'll have to do) and electronic course material; or the traditional textbook. They seem to have done the math and found that the electronic version is cheaper.
I'm with you on the history. But how much of the other stuff you mention really affects K-12 students? I can promise you we didn't get into the Kepler conjecture when I was in high school, and I took the full four year science course (biology, "applied science", chem, physics). The calculus stuff you mention is probably really interesting to number theorists, but I doubt it really matters to your average high school student (who, realistically, is probably not taking calculus anyway).
Our radio emissions are effectively omni-directional, and as such, fall off like 1/r^2... so for all practical purposes, those "I Love Lucy" reruns are lost in the noise. If they had an idea what carrier frequencies we were using, and did something like FFT over a really, really long integration time, they might pick something up, but I doubt it. There's too much space and doing so would take too long.
If you wanted the magnetometer to work, you'd probably have to point the headphone jack at it... I doubt it would get a very good magnetic signal unless the device was more or less horizontal. YMMV near the magnetic poles, though.
I'll sell you some special ones with gold-plated contacts that provide a much warmer, more "analog" light experience. All the visiophiles swear by them.
My thought is that the "cloaking" approach is going to be just as vulnerable to this - you know it won't be able to perfectly cloak a submarine, just give you some number of dB improvement in the ability to hide. And that will end up being vulnerable to improvements in amps/SPs as well.
And I have my doubts about the premise, anyway... you don't just have to improve the amps and signal processors, you would also have to improve the transducers. I'm doubtful that the amps and SPs are really improving as fast as Moore's law, and I know the transducers aren't.
At frequencies actually usable for submarine detection, this apparatus would have to be freakin' enormous - the cavities would need to be on the order of the same size as the wavelength... so you're talking meters in diameter. And you apparently need an array of them. I don't think that's something you can drag around on your submarine.
Not to get into a credentials war, but (former surface ship ASW evaluator) (have a masters degree in anti-submarine warfare from the Naval Postgrad School)
You need to consider two cases: active sonar (in which the searching ship is attempting to ensonify the target ship with sonar pulses, and then detect returning echoes) and passive sonar (in which the searching ship is just listening for sound emanations from the target). In the first case, you typically wouldn't be able to identify the submarine from a gap in return from the seabed - most of the energy in a sonar pulse ends up being entrapped in one or more "sound channels" in the water column, and never makes it to the seabed (exceptions apply, for certain water depths, etc, but still, so much sound is lost all the time that you couldn't use this... you'd get false alarms continually). In the second case, there are no real independent sources of sound that could be blocked by a passing submarine that you could use to detect them (or we'd be doing this already). So realistically, this is probably not a viable means of detecting a submarine.
I know, replying to myself is bad form, but... various navies also use anechoic coatings that are conceptually similar to this. The difference is that they are tuned to absorb incoming active sonar pulses of a frequency that you think your enemy is likely to use. They also have an effect of muffling any sounds radiating from your own boat.
then what happens if somebody comes up with a sonar that uses variable pitch?
Someone's already come up with it - the AN/SQS-53. No link, as for obvious reasons the Navy is not keen on talking about the operating frequencies of its gear, but it's well known that it uses multiple frequencies around 3.5 KHz for active sonar, and it's got a passive sonar capability to detect between very low and rather high frequencies.
"Ultrasound" (generally understood as meaning sound of a frequency too high to hear... i.e. more than 20khz) is pretty well useless in submarine detection, as high frequency sound has a very, very short propagation range in water. If they get to the point where they can do this with some frequency range that can go more than a few meters without being attenuated, then color me interested. But I'm guessing that would require an apparatus so huge that you wouldn't be able to deploy it anyway - the resonant cavities have to have a size of the same order of magnitude (maybe 1/4 wavelength?) of the sound wavelength... and for frequencies with any hope of propagating far (you're typically talking from 60 Hz to a few Khz), the wavelengths are HUGE - around 25 meters for 60 Hz. Bear in mind that you apparently need an array of these cavities, so you're talking about a rather enormous system.
I have a Mac, iTunes, iPhone, etc, at home too... and I buy all my music from Amazon.com. Their music downloader makes the process absolutely as easy as buying from iTMS. The process is almost exactly the same.
White roofs have the double effect of significantly reducing the air conditioning load within the building. This reduction in power consumption will probably reduce global warming by avoiding CO2 emissions as much if not more than the direct reflection effect... The peak power demand days in California are during the summer because of all the air conditioning.
The whole reason you want to do this is the reduction in air conditioning load - the change in the earth's total albedo is so tiny as not to be worth mentioning. Both lighter roofs and roads locally cool the area near/under them, which lets you run your A/C less. And since lighter roofs/roads don't cost any more over their life cycle, you not only save GHG emissions, you save money (in the form of lower electricity bills) too.
You're simply not gaining very much heat through your roof in the winter, no matter what color it is. Even if it wasn't snow covered (which it would be much of the winter, especially in upstate NY), the angle of the sun is just too low to heat the roof much. But in the summer, when the sun is beating down from more directly overhead, your attic gets hot, which makes it hard for the interior of your house to lose heat via the roof. If you use air conditioning at all, you're better off with a light roof.
The main effect would be from local cooling of areas that we're now using a bunch of fuel to air condition - if you lighten roofs and roads, you locally cool the houses near/under them. So we burn less fuel. So we put out less CO2. Which does, in fact, help correct the problems you're concerned about. Of course we can't directly cool the planet by painting a few things white - we could only possibly effect a tiny portion of the earth's surface that way, and it would be a negligible change in the planet's radiation budget. But we don't have to reflectively cool the entire planet... just cut down on the heat coming into our buildings, so we can use less energy. This has the happy side effect of saving money, too.
Because of 1) the tendency for heat to rise, and 2) the low angle of the sun in winter, contributions to your house's heat budget through solar heating of the roof are pretty minimal. By contrast, in the summer, the heat building up in your house is less able to escape via the attic when the attic is really hot. And white roofs really do lower the temperature in your attic. If you air condition even a little, you'd save money with a white roof pretty quickly. But I guess forgoing the savings is a small price to pay to be able to continue to pooh-pooh climate change.
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The general consensus is that people are being crybabies over the fact that they're being held to the contracts they signed, presumably of their own free will. No argument here. What baffles me is why people are even up in arms about upgrading - the differences between the iPhone 3G and 3GS are not really earth shattering - you can get a bigger capacity (up to 32 GB), autofocus camera, and the magnetometer... and that's about it. After all the hype over the new phone, I was pretty underwhelmed. Disclosure: I'm an iPhone 3g owner, and I'll be waiting until the next version to upgrade.
Human errors are responsible for 50%+ of all aviation mishaps.
From here:
So we don't have to depend on the engineers to get it right. We can (and do) check to see if they did.
This is so wrong-headed it's hard to even wrap my head around. For one thing, no one has established the cause of the Air France crash. Also, statistics show that pilot error is by far the leading cause of aviation mishaps. Finally, as has been pointed out over and over, the Airbus AUTOMATICALLY provides an increasing amount of control to the pilot in the event of abnormal conditions.
The weak link in aviation (in terms of safety) is the human crew. Systems that mitigate this problem are a good thing.
... if airplane computer makers got to do their own accident investigations. In fact, they're done by the NTSB, which really doesn't give a shit about litigation. And in any case, do you think a ruling of "pilot error" vs. "computer malfunction" would magically prevent lawsuits?
First, the computers involved are very, very rigorously tested. It's not like someone took Microsoft Flight Simulator, ported it to the airplane's computer, and said "here you go"! Second, statistics show that the top causes of crashes are 1) pilot error, 2) mechanical failure and 3) weather. Computer error doesn't even make the list.
The pilot activated a system he shouldn't have, failed to disengage it, and instead fought against what the autopilot was trying to do. This is not an argument in favor of human control of the airplane.
I'd say "mod parent up", but he's already at +5. I am a safety engineer, and I can promise you that the leading cause of aircraft mishaps is, by far, pilot error. Machines don't get confused, they never show up hung over, their attention never wanders, and their behavior is deterministic and rigorously tested. It's the people who screw up. And as for "the right to ask"... well, I don't know about you, but no one has ever taped my mouth shut as I get on the airplane. I can already ask this question, and get off the airplane if I don't like the answer. It happens that this is a stupid question to ask.
Dude, we're talking K-12 textbooks here, not college. So:
There is no "book buyback line", and they didn't pay 75 bucks at the beginning of the semester. They got it issued to them, and they'll turn it back in at the end of the course. What's more, the state of California is a seriously big textbook buyer, and they can no doubt get good terms from publishers based on the enormous amount of business they'd be bringing. The question is purely whether, all things considered, it's cheaper for the state to provide a cheap netbook (which they'll have to do) and electronic course material; or the traditional textbook. They seem to have done the math and found that the electronic version is cheaper.
I'm with you on the history. But how much of the other stuff you mention really affects K-12 students? I can promise you we didn't get into the Kepler conjecture when I was in high school, and I took the full four year science course (biology, "applied science", chem, physics). The calculus stuff you mention is probably really interesting to number theorists, but I doubt it really matters to your average high school student (who, realistically, is probably not taking calculus anyway).
Our radio emissions are effectively omni-directional, and as such, fall off like 1/r^2... so for all practical purposes, those "I Love Lucy" reruns are lost in the noise. If they had an idea what carrier frequencies we were using, and did something like FFT over a really, really long integration time, they might pick something up, but I doubt it. There's too much space and doing so would take too long.
If you wanted the magnetometer to work, you'd probably have to point the headphone jack at it... I doubt it would get a very good magnetic signal unless the device was more or less horizontal. YMMV near the magnetic poles, though.
I'll sell you some special ones with gold-plated contacts that provide a much warmer, more "analog" light experience. All the visiophiles swear by them.
My thought is that the "cloaking" approach is going to be just as vulnerable to this - you know it won't be able to perfectly cloak a submarine, just give you some number of dB improvement in the ability to hide. And that will end up being vulnerable to improvements in amps/SPs as well.
And I have my doubts about the premise, anyway... you don't just have to improve the amps and signal processors, you would also have to improve the transducers. I'm doubtful that the amps and SPs are really improving as fast as Moore's law, and I know the transducers aren't.
You don't need a metamaterial based apparatus like this to accomplish that - you just need an anechoic coating... which we already have.
At frequencies actually usable for submarine detection, this apparatus would have to be freakin' enormous - the cavities would need to be on the order of the same size as the wavelength... so you're talking meters in diameter. And you apparently need an array of them. I don't think that's something you can drag around on your submarine.
Not to get into a credentials war, but (former surface ship ASW evaluator) (have a masters degree in anti-submarine warfare from the Naval Postgrad School)
You need to consider two cases: active sonar (in which the searching ship is attempting to ensonify the target ship with sonar pulses, and then detect returning echoes) and passive sonar (in which the searching ship is just listening for sound emanations from the target). In the first case, you typically wouldn't be able to identify the submarine from a gap in return from the seabed - most of the energy in a sonar pulse ends up being entrapped in one or more "sound channels" in the water column, and never makes it to the seabed (exceptions apply, for certain water depths, etc, but still, so much sound is lost all the time that you couldn't use this... you'd get false alarms continually). In the second case, there are no real independent sources of sound that could be blocked by a passing submarine that you could use to detect them (or we'd be doing this already). So realistically, this is probably not a viable means of detecting a submarine.
I know, replying to myself is bad form, but... various navies also use anechoic coatings that are conceptually similar to this. The difference is that they are tuned to absorb incoming active sonar pulses of a frequency that you think your enemy is likely to use. They also have an effect of muffling any sounds radiating from your own boat.
Someone's already come up with it - the AN/SQS-53. No link, as for obvious reasons the Navy is not keen on talking about the operating frequencies of its gear, but it's well known that it uses multiple frequencies around 3.5 KHz for active sonar, and it's got a passive sonar capability to detect between very low and rather high frequencies.
"Ultrasound" (generally understood as meaning sound of a frequency too high to hear... i.e. more than 20khz) is pretty well useless in submarine detection, as high frequency sound has a very, very short propagation range in water. If they get to the point where they can do this with some frequency range that can go more than a few meters without being attenuated, then color me interested. But I'm guessing that would require an apparatus so huge that you wouldn't be able to deploy it anyway - the resonant cavities have to have a size of the same order of magnitude (maybe 1/4 wavelength?) of the sound wavelength... and for frequencies with any hope of propagating far (you're typically talking from 60 Hz to a few Khz), the wavelengths are HUGE - around 25 meters for 60 Hz. Bear in mind that you apparently need an array of these cavities, so you're talking about a rather enormous system.
I have a Mac, iTunes, iPhone, etc, at home too... and I buy all my music from Amazon.com. Their music downloader makes the process absolutely as easy as buying from iTMS. The process is almost exactly the same.
The whole reason you want to do this is the reduction in air conditioning load - the change in the earth's total albedo is so tiny as not to be worth mentioning. Both lighter roofs and roads locally cool the area near/under them, which lets you run your A/C less. And since lighter roofs/roads don't cost any more over their life cycle, you not only save GHG emissions, you save money (in the form of lower electricity bills) too.
You're simply not gaining very much heat through your roof in the winter, no matter what color it is. Even if it wasn't snow covered (which it would be much of the winter, especially in upstate NY), the angle of the sun is just too low to heat the roof much. But in the summer, when the sun is beating down from more directly overhead, your attic gets hot, which makes it hard for the interior of your house to lose heat via the roof. If you use air conditioning at all, you're better off with a light roof.
The main effect would be from local cooling of areas that we're now using a bunch of fuel to air condition - if you lighten roofs and roads, you locally cool the houses near/under them. So we burn less fuel. So we put out less CO2. Which does, in fact, help correct the problems you're concerned about. Of course we can't directly cool the planet by painting a few things white - we could only possibly effect a tiny portion of the earth's surface that way, and it would be a negligible change in the planet's radiation budget. But we don't have to reflectively cool the entire planet... just cut down on the heat coming into our buildings, so we can use less energy. This has the happy side effect of saving money, too.
Because of 1) the tendency for heat to rise, and 2) the low angle of the sun in winter, contributions to your house's heat budget through solar heating of the roof are pretty minimal. By contrast, in the summer, the heat building up in your house is less able to escape via the attic when the attic is really hot. And white roofs really do lower the temperature in your attic. If you air condition even a little, you'd save money with a white roof pretty quickly. But I guess forgoing the savings is a small price to pay to be able to continue to pooh-pooh climate change.