I think the main point is that applications rarely if ever take active steps to hide themselves whereas black hat applications often try ever so hard.
So a whitelist is likely to be more reliable, at least in principle, than the blacklist.
Of course the question is how things would get on to a whitelist in the first place- you don't want virus writers simply registering their malware before distribution; in principle distributing voting might work.
Actually, right now, there's hardly any market for it; and there's farmers who have turned their whole fields over to it, only to discover their entire field is only worth about $1.50. If they planted other crops they could have made a lot more. Last time I heard there wasn't even a refinery of any scale anywhere.
Jatropha is really only any good for poor land which isn't useful for other more valuable crops.
Bioethanol works just fine for rocket fuel, and most rockets are mostly made from aluminium, and aluminium is made with hydroelectricity. LOX is made from distilling air- again, we're not limited there.
Unlike from corn, bioethanol from sugar cane from places like Brazil has much larger than unity energy ratio to produce. Bioethanol is also carbon neutral (once you've set up a sustainable farm to grow the cane).
So making rockets even after the oil runs out is *not* a problem.
More point and bang.
Click means you've left the safety catch on.
OTOH imagine a Beowolf cluster of those! Me, I welcome my new robot overlords. Hot grits.. etc. etc.
How quickly does Kevlar lose strength in water? I checked the manufacturers data, and they indicated no significant loss within about a year or so (although all bets are off at high or low Ph).
This graphene oxide stuff sounds like it seriously can't take water in a major way though.
Usually mis-ignition will just cause rapid release of the N2O oxidizer,
Actually... toward the end of the burn and sometimes before the pressure in the tank goes down and combustion instabilities can set in; causing a buzzing- the flames are oscillating at the injectors.
But if the flames go back into the tank, then the tank can explode.
The scary thing is that manufacturers often induce these instabilities deliberately because it makes a crowd-pleasing buzzing noise, and doesn't usually explode.;-)
and designs are such that a clogged nozzle which would actually cause an explosion generally causes a safety valve to open and vent the excess pressure.
No, clogged nozzle is an all-she-wrote.
The only reason that hybrids often survive that kind of failure is that they deliberately use rubberised fuel- that kind of fuel just deforms its way through the nozzle and can't really block it. But if something does seriously block the nozzle (and it has happened)- the chamber is going to explode in a shrapnel-shedding way, and no safety valve is going to realistically stop it.
The sewage gets processed dumped into a river, the river leads out to sea, the sea evaporates, forms clouds and rains back on the mountains again. It's basically distillation.
Hence the water you drink is distilled sewage. Enjoy!
Running and getting experience of recycling systems *is* human exploration. If you back space exploration with humans in any way shape or form, that's what it looks like.
It's also incredibly naive to think that if the money wasn't spent on this it would be spent on housing. It would probably get spent on Iraq.
IRC the shuttle one just collects the waste, and the waste is disposed of on the ground. Don't forget that the Shuttle is only on orbit for a couple of weeks max.
The Russian system is actually a full sewage system, and turns the urine back into drinking water. That saves launch costs at ~20,000/kgon the water. With 3-6 astronauts up there it pays to do this.
And it's unlikely that NASA could do this, the R&D alone would be more than that, and this is a full working toilet/waste reclaimation system.
No, it's the Earth equivalent of not just the toilet, but the sewage plant as well. It actually turns urine into drinking water.
If you think about it, a litre of water made from urine saves $10,000/kg in launch costs. The system will quickly pay for itself with 3-6 astronauts up there.
I've run the numbers before, and for a few thousand flights a year, even a few tens of thousands of flights the impacts are negligible. Even for an orbital flight the fuel use per person is high, but not stupidly so; about the same as flying around the world a couple of times. About the same amount of fuel used by one person in one year in their car.
For a suborbital flight, divide by maybe 4.
If you were talking a million flights per year, then maybe it would start to get more critical, but there's lots of things that could be done to reduce the environmental costs if that happened (different ways to build launch vehicles, hypersonic tethers and all kinds of other magic). Also, rockets can burn biofuels just fine, so there needn't be any net CO2 increase.
Rockets aren't environmental milk and honey, but they're not really significantly that much worse than conventional aeroplanes.
It's really important that exploration and discovery be cost effective though. Right now, it isn't really.
The point is economies of scale.
A modern car is about as complex as any rocket; it has pumps, gas turbines, high temperatures, guidance system (GPS), servos, valves, computers, tanks, etc. etc.
Sure there are many differences, but in many respects a car is actually more complicated, and a new modern car costs billions to design, which is similar to the R&D on rockets; it's really easy to underestimate how complex cars are, and how simple rockets are.
The thing is that a modern car costs a few tens of thousands, whereas a modern rocket costs a few tens of million.
Why? Economies of scale; rockets are built a few a year, whereas cars are built every few minutes.
For rockets, and space to open up to exploration, we need the same economies of scale. That's why we need people going up into space for tourism- it's a potentially large market, and those economies of scale kick right in. Tourism reduces costs for everybody and everything that goes into space. People like zero-g for a few weeks or even a few minutes. That's a market, and it's a market for thousands of flights a year. That will probably reduce the costs below the magic $1000/kg mark, below which it is thought that the space market will grow organically.
You *can* buy essentially non oversold connections though. But at say, ~50x the price, because the costs to the ISP are ~50x higher.
To some degree you get what you pay for; and most people wouldn't want to have to pay that.
The problem with 'paying for what you use' is it's too easy for them to grievously overcharge you for the extra.
In most cases it's much much better if the service just gradually slows for you as you have used up more and more total bandwidth. That way there's no nasty surprise at the end of the month.
The thing is it still costs money though to light it all up. If you want twice as much bandwidth it costs a bit less than twice the cost (less due to economies of scale).
There's big differences between a T1 line and a normal internet connection. The biggest is possibly the contention ratio. The T1 line is far, far less contended. In practice the normal internet connection has a contention ratio of at least 20:1 and often 50:1 or even 150:1 (including the fact that the users are only online maybe 1/3 of the day).
So the T1 line actually does provide orders of magnitude more throughput. And that's before we start talking about the service you're getting, the T1 line should be fixed incredibly quickly if anything goes wrong, it's treated as money, and often there are penalty clauses etc. etc.
I would certainly hope and expect that the flash drive has some kind of wear averaging so that repetitively writing to the swap file moves the hot bits around the harddrive.
You send the message you want to broadcast/distribute to a signing authority together with proof of who you are, what area it applies to and the time, and they sign it and send it back to you. Nobody needs to ever see the signing authorities' private key.
Well, there could be a single centralised signature authority that signs messages sent to it with a single private key, the centralised authority would have to implement some kind of separate authentication scheme to make sure that they only sign messages from people that are authenticated to help ensure that they don't end up signing messages from bad guys.
It doesn't have to be perfect it just has to be good enough. Perfect security doesn't exist.
Re:encryption cant help..
on
Is Your GPS Naive?
·
· Score: 3, Interesting
It [i]could[/i] work if public key encryption was used for authentication, and the messages were timestamped and geolocated to prevent replay attacks.
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Yeah. And flying cars. They promised us flying cars.
Well, they'll have a camera, so they're sure to get video of it. What more could you want?
I think the main point is that applications rarely if ever take active steps to hide themselves whereas black hat applications often try ever so hard. So a whitelist is likely to be more reliable, at least in principle, than the blacklist. Of course the question is how things would get on to a whitelist in the first place- you don't want virus writers simply registering their malware before distribution; in principle distributing voting might work.
Actually, right now, there's hardly any market for it; and there's farmers who have turned their whole fields over to it, only to discover their entire field is only worth about $1.50. If they planted other crops they could have made a lot more. Last time I heard there wasn't even a refinery of any scale anywhere.
Jatropha is really only any good for poor land which isn't useful for other more valuable crops.
Most of the cost is tax. Want to bet they won't tax it too?
Bioethanol works just fine for rocket fuel, and most rockets are mostly made from aluminium, and aluminium is made with hydroelectricity. LOX is made from distilling air- again, we're not limited there.
Unlike from corn, bioethanol from sugar cane from places like Brazil has much larger than unity energy ratio to produce. Bioethanol is also carbon neutral (once you've set up a sustainable farm to grow the cane).
So making rockets even after the oil runs out is *not* a problem.
More point and bang. Click means you've left the safety catch on. OTOH imagine a Beowolf cluster of those! Me, I welcome my new robot overlords. Hot grits.. etc. etc.
How quickly does Kevlar lose strength in water? I checked the manufacturers data, and they indicated no significant loss within about a year or so (although all bets are off at high or low Ph). This graphene oxide stuff sounds like it seriously can't take water in a major way though.
Usually mis-ignition will just cause rapid release of the N2O oxidizer,
Actually... toward the end of the burn and sometimes before the pressure in the tank goes down and combustion instabilities can set in; causing a buzzing- the flames are oscillating at the injectors.
But if the flames go back into the tank, then the tank can explode.
The scary thing is that manufacturers often induce these instabilities deliberately because it makes a crowd-pleasing buzzing noise, and doesn't usually explode. ;-)
and designs are such that a clogged nozzle which would actually cause an explosion generally causes a safety valve to open and vent the excess pressure.
No, clogged nozzle is an all-she-wrote.
The only reason that hybrids often survive that kind of failure is that they deliberately use rubberised fuel- that kind of fuel just deforms its way through the nozzle and can't really block it. But if something does seriously block the nozzle (and it has happened)- the chamber is going to explode in a shrapnel-shedding way, and no safety valve is going to realistically stop it.
You drink treated sewage anyway.
The sewage gets processed dumped into a river, the river leads out to sea, the sea evaporates, forms clouds and rains back on the mountains again. It's basically distillation.
Hence the water you drink is distilled sewage. Enjoy!
No, 1.9 tonnes of Urine between them. If 3 astronauts each pass a litre a day, that's less than 2 years.
Running and getting experience of recycling systems *is* human exploration. If you back space exploration with humans in any way shape or form, that's what it looks like.
It's also incredibly naive to think that if the money wasn't spent on this it would be spent on housing. It would probably get spent on Iraq.
IRC the shuttle one just collects the waste, and the waste is disposed of on the ground. Don't forget that the Shuttle is only on orbit for a couple of weeks max.
The Russian system is actually a full sewage system, and turns the urine back into drinking water. That saves launch costs at ~20,000/kgon the water. With 3-6 astronauts up there it pays to do this.
And it's unlikely that NASA could do this, the R&D alone would be more than that, and this is a full working toilet/waste reclaimation system.
No, it's the Earth equivalent of not just the toilet, but the sewage plant as well. It actually turns urine into drinking water.
If you think about it, a litre of water made from urine saves $10,000/kg in launch costs. The system will quickly pay for itself with 3-6 astronauts up there.
$2 bills ... that cost Woz $3!
(He has them serrated and booked and that's what it costs in the end...)
I've run the numbers before, and for a few thousand flights a year, even a few tens of thousands of flights the impacts are negligible. Even for an orbital flight the fuel use per person is high, but not stupidly so; about the same as flying around the world a couple of times. About the same amount of fuel used by one person in one year in their car.
For a suborbital flight, divide by maybe 4.
If you were talking a million flights per year, then maybe it would start to get more critical, but there's lots of things that could be done to reduce the environmental costs if that happened (different ways to build launch vehicles, hypersonic tethers and all kinds of other magic). Also, rockets can burn biofuels just fine, so there needn't be any net CO2 increase.
Rockets aren't environmental milk and honey, but they're not really significantly that much worse than conventional aeroplanes.
It's really important that exploration and discovery be cost effective though. Right now, it isn't really.
The point is economies of scale.
A modern car is about as complex as any rocket; it has pumps, gas turbines, high temperatures, guidance system (GPS), servos, valves, computers, tanks, etc. etc.
Sure there are many differences, but in many respects a car is actually more complicated, and a new modern car costs billions to design, which is similar to the R&D on rockets; it's really easy to underestimate how complex cars are, and how simple rockets are.
The thing is that a modern car costs a few tens of thousands, whereas a modern rocket costs a few tens of million.
Why? Economies of scale; rockets are built a few a year, whereas cars are built every few minutes.
For rockets, and space to open up to exploration, we need the same economies of scale. That's why we need people going up into space for tourism- it's a potentially large market, and those economies of scale kick right in. Tourism reduces costs for everybody and everything that goes into space. People like zero-g for a few weeks or even a few minutes. That's a market, and it's a market for thousands of flights a year. That will probably reduce the costs below the magic $1000/kg mark, below which it is thought that the space market will grow organically.
You *can* buy essentially non oversold connections though. But at say, ~50x the price, because the costs to the ISP are ~50x higher. To some degree you get what you pay for; and most people wouldn't want to have to pay that.
The problem with 'paying for what you use' is it's too easy for them to grievously overcharge you for the extra.
In most cases it's much much better if the service just gradually slows for you as you have used up more and more total bandwidth. That way there's no nasty surprise at the end of the month.
The thing is it still costs money though to light it all up. If you want twice as much bandwidth it costs a bit less than twice the cost (less due to economies of scale).
There's big differences between a T1 line and a normal internet connection. The biggest is possibly the contention ratio. The T1 line is far, far less contended. In practice the normal internet connection has a contention ratio of at least 20:1 and often 50:1 or even 150:1 (including the fact that the users are only online maybe 1/3 of the day).
So the T1 line actually does provide orders of magnitude more throughput. And that's before we start talking about the service you're getting, the T1 line should be fixed incredibly quickly if anything goes wrong, it's treated as money, and often there are penalty clauses etc. etc.
They're just not comparable.
More like 10 million writes.
I would certainly hope and expect that the flash drive has some kind of wear averaging so that repetitively writing to the swap file moves the hot bits around the harddrive.
You send the message you want to broadcast/distribute to a signing authority together with proof of who you are, what area it applies to and the time, and they sign it and send it back to you. Nobody needs to ever see the signing authorities' private key.
Well, there could be a single centralised signature authority that signs messages sent to it with a single private key, the centralised authority would have to implement some kind of separate authentication scheme to make sure that they only sign messages from people that are authenticated to help ensure that they don't end up signing messages from bad guys.
It doesn't have to be perfect it just has to be good enough. Perfect security doesn't exist.
It [i]could[/i] work if public key encryption was used for authentication, and the messages were timestamped and geolocated to prevent replay attacks.