So now we've simultaneously video tower failure, a plane that must land rather than divert, a light plane crash, and the fact of the light plane crash is unknown to the controller and pilot of the incoming flight. I'll take those odds.
The answer is the incoming flight lands on top of the crashed light plane, which is probably what it would have had to do anyway if the cameras were operating, given that we've established it is unable to divert. The incoming flight suffers 0-50% casualties and is a hull loss.
Air traffic control relies mostly on transponders and radar, so quite likely you could continue operations even without video. Video would be most useful for directing taxiing. However you can decrease your workload by >90% by keeping departing planes on the ground and putting incoming planes into a holding pattern or diverting them. The only planes that you must deal with are those in the air and with inadequate fuel to divert, which almost never happens (only if they've suffered significant delays/diversions prior to this point.)
Short answer: Lots of delayed/diverted and frustrated passengers, but no boom.
The explanation wasn't very clear, but I think this is how it works. Student in 2015: "We charge you $34k tutition, but you are eligible for $20k grant, so you pay us $14k." Same student in 2016: "We charge you $20k tuition, but you are eligible for $6k grant, so you pay us $14k" (NOTE: $14k is just an example, number made up from top of my head.) For that student, there is no financial impact on the university for the cut in tuition. There will be some loss because of students who were paying over $20k after grants, who will now be paying only $20k, but they say there are very few of these students. They anticipate getting more students because $34k tuition was scaring people off from applying, even those who in the end would only have been paying $14k (or whatever) after grants. This extra volume will supposedly offset their losses.
Problem: "We're losing money on every student, but we make up for it with volume". Unless that $14k after-grants payment is actually enough to cover the university's costs for that student, getting more of them won't help.
From the article (and the announcement it links to), I'm really struggling to figure out what the big deal is.
A rewritable 36 bit label. Presumably that means you have 36 dots, each of which can be black or white (say) and you can change their state somehow. I could (a little less conveniently) do the same with a sticker with 36 dots on it, each either filled or hollow. Whenever I want to change it, I just print a new sticker with the new bit pattern and stick it over the old one.
How does this give all the cryptographic goodness they talk about?
They say you'll be able to cryptographically confirm authenticity off-line. But 36 bits is easily brute-forcible. If you can check the authenticity of the 36 bit pattern, the man in the middle can check all 2^36 bit patterns for authenticity and use whichever authenticated bit patterns give the message they want.
The engineers at Xerox aren't stupid, so presumably there is something to this. However in going from the minds of the engineers to the mind of the journalist to the article to my mind, somewhere something vital has been lost.
The worst, by the way, are web sites which require you to pick a super-secure password (at least 12 characters long, must contain punctuation, both upper and lower case letters, a number character, an Egyptian hieroglyph, and must not match the last 15 passwords used in the past and must be changed ever 30 days)--then stores the password and password history as plain text in the user database. Those are the guys I'd love to murder in cold blood.
No, cold-blood-murder is reserved for sites that do all of the above and also send you a confirmation e-mail containing your password in clear text.
Arthur C Clarke's novel "Imperial Earth" does this: The future USA have decided that anyone who wants to be in the Whitehouse should never be allowed to be there. They make a list of people who are competent and would need to be dragged kicking and screaming into the Whitehouse, but once there will do their best. Then they just choose their president by lottery from that list.
So you harpoon a comet with a velocity relative to you of 10 km/s. You have 1000km of tether. That means that if you didn't apply any braking, you'd have just 100s before your tether ran out. With little bit of physics, I find that the probe would need to accelerate at 50m/s^2 (over 5g) to match velocity with the comet before running out of tether (which takes 200s because now it is accelerating). So the tether and the harpoon need to withstand a tension of 5 times the earth-weight of the probe, without breaking or pulling the harpoon out of the comet. Now assume the probe is 1000kg. (For simplicity I'll ignore the mass of the tether and the rotation of the tether reel, although that would probably be a deal breaker too.) Force = 1000kg x 50m/s^2 = 50000N. Distance acted over = 1000km = 10^6 m, so work = 5x10^4 x 10^6 = 5 x 10^10 J. It is 200 s before the tether runs out, so power = 5x10^10/200 = 2.5x10^8W = 250 MW. That power has to be stored and/or dissipated, and you have at best 1000kg with which to do it.
It all gets very much easier if your relative velocity with the comet is much lower, but then you're not gaining much, and intercepting a comet with only few km/s relative velocity is very hard in itself.
It is a pretty idea, but I can't see it working with anything vaguely like current technology.
This is fine - they're not pretending those impacts don't happen, they are just not what they're studying. They are asking "What does the fallout do to people some distance from the accident?"
The exposure people get early in the accident and very close to the reactors depends hugely on the nature of the accident. At Chernobyl, there were many firefighters within meters of an exposed critical core, resulting in a large toll from acute radiation sickness. At Fukushima, the cores ceased to be critical seconds after the quake and tens of minutes before the tsunami, and radiation was only released days later, so there was no acute radiation sickness.
By contrast, the effect of the fallout is much less dependent on the nature of the accident, just on how much radioactive material was released*. It can sensibly be studied without specifying details of how the accident happened.
* There is some dependence: the relative quantity of short lived isotopes such as Iodine-131 in the fallout depends somewhat on how long the radioactive material was contained prior to release.
The more niche your research topic, the longer the title has to be to describe it, and correspondingly the fewer people will be interested. Compare, for example, "A New Hierarchy of Phylogenetic Models Consistent with Heterogeneous Substitution Rates" with "The Origin of Chemical Elements". While one will be much more cited that the other, the reason isn't the title length.
For the cost of one shuttle launch you could more than pay for SpaceX's entire development program so far. For two launches you could pay for their development so far plus the extra they'll need to finish the Dragon capsule and "man-rate" the system, and still have some money left over for a couple of launches (each of which can carry as many crew as the shuttle.)
(I'm taking the cost of a shuttle launch as about $1.5B. Lower values can be argued for, adjust the above as needed for your preferred cost.)
For a few more shuttle launches and a several year wait, Blue Origins would likely be able to field a man-rated rocket, if you want multiple space taxi companies to chose from. ULA could do it too, but that would probably cost you ten shuttle launches.
The shuttle was hideously expensive and needed to go.
It isn't clear to me whether they collect heat and use some heat engine, or whether they use a small area of high cost high efficiency high temperature photovoltaic cells. As I've complained elsewhere, the articles provide almost no detail. There is mention of cooling water, but either possibility could use that.
You'd use differential GPS. Wikipedia says this has accuracy of 10cm in the best case. Whether that is good enough for this application I'm not sure. Given that affordability is a big part of their goal, if they were taking this approach they'd not attach a GPS to each mirror, but rather have two receivers that they used for a callibration stage and then wouldn't be needed again unless something shifted. You'd need to know orientation as well as location for the mirrors.
I doubt this is what they're doing, but who knows.
TFA is lacking in details about how this works, but if you follow the link you get to a Guardian article which is lacking in details, but links to the projects website which excessively uses gratuitous Javascript and is lacking in details.
They talk about "plonkability" - that the mirror structures can just be plonked on the ground and will 'just work'. This suggests to me that somewhere in their system is some intelligence or calibration which is able to notice where each mirror is relative to the target and adapt its pointing accordingly. Their photos show the target tower having two rectangular surfaces pointed towards the mirrors. I suspect the plane white surface is there to aid mirror pointing calibration in some way, but I don't know.
After a bit more searching I find this as the most informative article so far. (I did spot a misprint: "500 times faster than DRAM" should be "500 times faster than NAND" - confirmed by following the link in that paragraph.)
Although it is hard to know because of the secrecy, it seems like there is a whole lot of stuff around 'intellectual property' and corporations getting to sue governments over policy changes which has been pushed hard by the USA and opposed not quite as hard by everyone else. So there is lots of stuff that objectionable to everyone but the USA. (Given that the USA parliaments haven't been allowed to see the TPP, possibly not even they want it. This could be stuff wanted only by the USA negotiators, not the country.)
What I want to see is USA kicked out of the TPP, then renegotiate to get rid of all the bad stuff USA pushed in. After that, the USA can negotiate for a late entry into the agreement. They can propose all this IP stuff, and the rest of us can consider whether we that badly want USA in the TPP.
That is pretty much a pipe dream, but more realistically: I'd like to see the governments of all participating countries go through all the provisions and state how strongly they are for or against them. If there are any bits that are liked only by negotiators, this would show them up.
It really worries me that this is secretly negotiated by people with almost no democratic oversight and will be presented as a monolithic take-it-or-leave-it with greater effective force than the laws of the participating nations.
Buying into the TPP is effectively accepting a huge lump of laws you had almost no say over and are almost impossible to modify in future.
Slashdot Mirror
So now we've simultaneously video tower failure, a plane that must land rather than divert, a light plane crash, and the fact of the light plane crash is unknown to the controller and pilot of the incoming flight. I'll take those odds.
The answer is the incoming flight lands on top of the crashed light plane, which is probably what it would have had to do anyway if the cameras were operating, given that we've established it is unable to divert. The incoming flight suffers 0-50% casualties and is a hull loss.
I think your solution is too expensive for all but major airports. I think the airport-sized selfie stick will be much cheaper.
You're in radio communication with everyone near that runway. You tell them to get the **** out of the way.
I think it isn't unusual now for smallish airports to be controlled from a distant location.
Air traffic control relies mostly on transponders and radar, so quite likely you could continue operations even without video. Video would be most useful for directing taxiing. However you can decrease your workload by >90% by keeping departing planes on the ground and putting incoming planes into a holding pattern or diverting them. The only planes that you must deal with are those in the air and with inadequate fuel to divert, which almost never happens (only if they've suffered significant delays/diversions prior to this point.)
Short answer: Lots of delayed/diverted and frustrated passengers, but no boom.
The explanation wasn't very clear, but I think this is how it works.
Student in 2015: "We charge you $34k tutition, but you are eligible for $20k grant, so you pay us $14k."
Same student in 2016: "We charge you $20k tuition, but you are eligible for $6k grant, so you pay us $14k"
(NOTE: $14k is just an example, number made up from top of my head.)
For that student, there is no financial impact on the university for the cut in tuition. There will be some loss because of students who were paying over $20k after grants, who will now be paying only $20k, but they say there are very few of these students. They anticipate getting more students because $34k tuition was scaring people off from applying, even those who in the end would only have been paying $14k (or whatever) after grants. This extra volume will supposedly offset their losses.
Problem: "We're losing money on every student, but we make up for it with volume". Unless that $14k after-grants payment is actually enough to cover the university's costs for that student, getting more of them won't help.
From the article (and the announcement it links to), I'm really struggling to figure out what the big deal is.
A rewritable 36 bit label. Presumably that means you have 36 dots, each of which can be black or white (say) and you can change their state somehow. I could (a little less conveniently) do the same with a sticker with 36 dots on it, each either filled or hollow. Whenever I want to change it, I just print a new sticker with the new bit pattern and stick it over the old one.
How does this give all the cryptographic goodness they talk about?
They say you'll be able to cryptographically confirm authenticity off-line. But 36 bits is easily brute-forcible. If you can check the authenticity of the 36 bit pattern, the man in the middle can check all 2^36 bit patterns for authenticity and use whichever authenticated bit patterns give the message they want.
The engineers at Xerox aren't stupid, so presumably there is something to this. However in going from the minds of the engineers to the mind of the journalist to the article to my mind, somewhere something vital has been lost.
The worst, by the way, are web sites which require you to pick a super-secure password (at least 12 characters long, must contain punctuation, both upper and lower case letters, a number character, an Egyptian hieroglyph, and must not match the last 15 passwords used in the past and must be changed ever 30 days)--then stores the password and password history as plain text in the user database. Those are the guys I'd love to murder in cold blood.
No, cold-blood-murder is reserved for sites that do all of the above and also send you a confirmation e-mail containing your password in clear text.
Arthur C Clarke's novel "Imperial Earth" does this: The future USA have decided that anyone who wants to be in the Whitehouse should never be allowed to be there. They make a list of people who are competent and would need to be dragged kicking and screaming into the Whitehouse, but once there will do their best. Then they just choose their president by lottery from that list.
1000km came from the article, which discussed a tether of 62 to 620 miles length.
So you harpoon a comet with a velocity relative to you of 10 km/s. You have 1000km of tether. That means that if you didn't apply any braking, you'd have just 100s before your tether ran out. With little bit of physics, I find that the probe would need to accelerate at 50m/s^2 (over 5g) to match velocity with the comet before running out of tether (which takes 200s because now it is accelerating). So the tether and the harpoon need to withstand a tension of 5 times the earth-weight of the probe, without breaking or pulling the harpoon out of the comet. Now assume the probe is 1000kg. (For simplicity I'll ignore the mass of the tether and the rotation of the tether reel, although that would probably be a deal breaker too.) Force = 1000kg x 50m/s^2 = 50000N. Distance acted over = 1000km = 10^6 m, so work = 5x10^4 x 10^6 = 5 x 10^10 J. It is 200 s before the tether runs out, so power = 5x10^10/200 = 2.5x10^8W = 250 MW. That power has to be stored and/or dissipated, and you have at best 1000kg with which to do it.
It all gets very much easier if your relative velocity with the comet is much lower, but then you're not gaining much, and intercepting a comet with only few km/s relative velocity is very hard in itself.
It is a pretty idea, but I can't see it working with anything vaguely like current technology.
Does anyone care to poke holes in my reasoning?
here. (Warning: 50 page graphics intensive PDF.)
Optical path on page 26. 6Gb of raw data every 17 seconds (page 32).
On the other hand, if she were still CEO of HP, she'd be getting lots of donations to run for president - from HP employees and shareholders.
This is fine - they're not pretending those impacts don't happen, they are just not what they're studying. They are asking "What does the fallout do to people some distance from the accident?"
The exposure people get early in the accident and very close to the reactors depends hugely on the nature of the accident. At Chernobyl, there were many firefighters within meters of an exposed critical core, resulting in a large toll from acute radiation sickness. At Fukushima, the cores ceased to be critical seconds after the quake and tens of minutes before the tsunami, and radiation was only released days later, so there was no acute radiation sickness.
By contrast, the effect of the fallout is much less dependent on the nature of the accident, just on how much radioactive material was released*. It can sensibly be studied without specifying details of how the accident happened.
* There is some dependence: the relative quantity of short lived isotopes such as Iodine-131 in the fallout depends somewhat on how long the radioactive material was contained prior to release.
The more niche your research topic, the longer the title has to be to describe it, and correspondingly the fewer people will be interested. Compare, for example, "A New Hierarchy of Phylogenetic Models Consistent with Heterogeneous Substitution Rates" with "The Origin of Chemical Elements". While one will be much more cited that the other, the reason isn't the title length.
Thanks, that is hugely more informative. A big bit of information is that they are using molten salt thermal storage.
For the cost of one shuttle launch you could more than pay for SpaceX's entire development program so far. For two launches you could pay for their development so far plus the extra they'll need to finish the Dragon capsule and "man-rate" the system, and still have some money left over for a couple of launches (each of which can carry as many crew as the shuttle.)
(I'm taking the cost of a shuttle launch as about $1.5B. Lower values can be argued for, adjust the above as needed for your preferred cost.)
For a few more shuttle launches and a several year wait, Blue Origins would likely be able to field a man-rated rocket, if you want multiple space taxi companies to chose from. ULA could do it too, but that would probably cost you ten shuttle launches.
The shuttle was hideously expensive and needed to go.
It isn't clear to me whether they collect heat and use some heat engine, or whether they use a small area of high cost high efficiency high temperature photovoltaic cells. As I've complained elsewhere, the articles provide almost no detail. There is mention of cooling water, but either possibility could use that.
You'd use differential GPS. Wikipedia says this has accuracy of 10cm in the best case. Whether that is good enough for this application I'm not sure. Given that affordability is a big part of their goal, if they were taking this approach they'd not attach a GPS to each mirror, but rather have two receivers that they used for a callibration stage and then wouldn't be needed again unless something shifted. You'd need to know orientation as well as location for the mirrors.
I doubt this is what they're doing, but who knows.
TFA is lacking in details about how this works, but if you follow the link you get to a Guardian article which is lacking in details, but links to the projects website which excessively uses gratuitous Javascript and is lacking in details.
They talk about "plonkability" - that the mirror structures can just be plonked on the ground and will 'just work'. This suggests to me that somewhere in their system is some intelligence or calibration which is able to notice where each mirror is relative to the target and adapt its pointing accordingly. Their photos show the target tower having two rectangular surfaces pointed towards the mirrors. I suspect the plane white surface is there to aid mirror pointing calibration in some way, but I don't know.
Copyright so doesn't work like that. You pay for a book, but doing so doesn't let you scan it and post it on the internet.
After a bit more searching I find this as the most informative article so far. (I did spot a misprint: "500 times faster than DRAM" should be "500 times faster than NAND" - confirmed by following the link in that paragraph.)
TFA was very short on detail, so I went looking for more. Unfortunately, there seems not to be much more out there - everyone is reporting on the same short-on-detail presentation. Here's a few which seemed to me to have something to add:
kitguru has more pictures
pcworld has pictures of actual silicon (not that it has any visible detail)
digitaltrends has some interesting commentary (last two paragraphs).
Thirty thousand yen - roughly $250-$300.
Although it is hard to know because of the secrecy, it seems like there is a whole lot of stuff around 'intellectual property' and corporations getting to sue governments over policy changes which has been pushed hard by the USA and opposed not quite as hard by everyone else. So there is lots of stuff that objectionable to everyone but the USA. (Given that the USA parliaments haven't been allowed to see the TPP, possibly not even they want it. This could be stuff wanted only by the USA negotiators, not the country.)
What I want to see is USA kicked out of the TPP, then renegotiate to get rid of all the bad stuff USA pushed in. After that, the USA can negotiate for a late entry into the agreement. They can propose all this IP stuff, and the rest of us can consider whether we that badly want USA in the TPP.
That is pretty much a pipe dream, but more realistically: I'd like to see the governments of all participating countries go through all the provisions and state how strongly they are for or against them. If there are any bits that are liked only by negotiators, this would show them up.
It really worries me that this is secretly negotiated by people with almost no democratic oversight and will be presented as a monolithic take-it-or-leave-it with greater effective force than the laws of the participating nations.
Buying into the TPP is effectively accepting a huge lump of laws you had almost no say over and are almost impossible to modify in future.
Again, this is old news (and conspiracy theorists can think up other sources for a 777 flaperon.) What new information has led to this announcement?