This isn't about 'tinkering' with gadgets- it's about fraudulently changing the phone to allow it to steal airtime off a company, or allow the crook to sell the phone off and make profit from their violent crimes. And the phone is for all intents and purposes always a stolen phone.
And these phones are usually obtained via violence, often to children who almost uniformly carry these for safety reasons; and then get mugged.
As other posters have pointed out- there are whole industries out there, that currently are reasonably legal, that exist solely to make these changes to phones. That cannot be a good thing.
If you want to hack your own phone- frankly, the chances of getting caught are really tiny- go ahead knock yourself out.
you could just make stealing the phone punshiable by 10 years.
Probably not as good; but might work. The young thugs that do the stealing probably aren't the ones that do the reprocessing.
I think that the point of this legislation is that it means that you've then committed 2 separate breaches of the law:
a) you stole the phone
b) you reprogrammed it
If stealing phones gets you stuck inside for 5 years, and reprogramming these phones gets you another 5, I think that thieves may well consider doing something else instead.
google cache
You'll see the cost per kg of liquid hydrogen was $2.60 in 1980. I expect it has gone up since then, but not so very much; and it does vary a bit- e.g. if you order enough hydrogen the price goes down.
The Space Shuttle's main tank contains 101 tonnes of liquid hydrogen. Assuming a price of $5/kg, that's $505,000 worth of hydrogen (since there are 1000kg to the tonne). Right?
The cost of adding an extra Space Shuttle to the yearly launch manifest is about $200 million.
Congratulations, you have just learnt something!
Oh yeah the Space Shuttle also burns 606 tonnes of LOX. LOX costs vary, but they are typically a few cents per kg. You can multiply that up if you wish, but the costs are more than 10x less than the hydrogen.
Batteries are heavier. Still, they didn't actually say AFAIK, but I think that they were planning to put the flywheels in the station, not on the train; so the weight doesn't matter much. It may be that the flywheels are cheaper than the batteries, and they only have to store the energy for a short time in this case anyway- so it's a perfect application.
Re:Somewhat related question...
on
Future of Wi-Fi
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· Score: 2
In the article, if I understood it correctly, they talk about dynamically allocate frequencies so everyone can have a piece when needed.
Yes, just like tuning in a radio. They call that 'frequency division multiplexing'.
I can imagine it's kind of like multithreading but with air waves, every one would get it's slice once in while.
Yes, just like the internet. They call that 'time division multiplexing'. That's used too.
There's also 'spatial multiplexing' where each user would use a directional aerial, so that two people could send at the same time and the same frequency but they wouldn't interfere because each aerial would be pointing in a different direction.
My question thereof is this. How does one calculates bandwith available over a given frequency?
There's Shannons law which tells you how much bandwidth you would get, but it depends on the amount of noise there is around too.
Actually, it's not a single frequency- it's over a range of frequencies; you can't get any information sent exactly at 100 Mhz, but you can fit it in from 100-105 Mhz... the number of bits per second you'll manage will depend on the amount of noise drowning you out.
Re:why are we securing it this way?
on
Future of Wi-Fi
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· Score: 2
Yeah, but the wireless shouldn't be a DMZ, it should be treated as insecure. The difference is that anyone within range of your network can get access to it. Normally a DMZ is only accessible via a firewall.
It makes a difference too. The users on the wireless network often have tunneling software to get to the intranet. If they get hacked, then your security may be toast.
Still, a good firewall on each of the wireless users might work... maybe.
Check out all that stuff floating outside Mars orbit!
It's icy asteroids outside the icing point of the sun- at that distance water is in the form of ice and sublimes only over enormous timescales.
Water is an okish fuel for rockets- the ISP of steam is about 190 seconds, just under half the thrust of the space shuttle main engines, even if you don't split it into hydrogen and oxygen.
Basically, if you can reach that, the whole solar system is open to you- so much fuel you wouldn't know which way to go first...
Also scramjets have a greater ISP than most regular chemical engines and have no moving parts, unlike the hundreds of parts on moden rocket engines.
In its simplest form rocket engine has no moving parts either (ok, there's usually a few valves, but scramjet would need them also.)
The Space Shuttle Main Engines have complicated turbopumps, but I wouldn't exactly hold that up as a shining example of rocket engineering; but the SRBs don't have any moving parts.
ISP is not everything- it's recently been realised that fuels that have lower ISP can give more payload to orbit than hydrogen/LOX. Reaching orbit is much more subtle than you would expect. Scramjets actually look like a bad idea for reaching orbit; they're too heavy- but may be good for a first stage, where the weight doesn't matter nearly so much.
I've personally found it easier to achieve in languages other than C/C++; Java is better for this. The point is that C/C++ ramp up the care required rather significantly- dereferencing pointers/variation in the compiler/automagic casts/crashes rather than tracebacks- all these things and more do not make for a pleasant programming experience, and that usually kicks me out- as soon as you're going "what the f**k caused that?"- and hunting around for more data- you're probably gone.
Still some debugging environments are much better than others, but I work in embedded systems- where the environments often suck and suck badly.
Still, if you do manage to get in the flow in these languages, then more power to you, your error rate will go way down, and you need more or less zero error rate in many tasks for C/C++.
He pointed to the fact that an Irish university (sorry - don't remember which) had spent quite some time reproducing the experiment, and that this re-running of the experiment had failed to verify a single claim.
However, it may be that they did something wrong- perhaps some detail was performed incorrectly, or something. It does happen sometimes.
As a similar, but not exact example, I once heard about a chemistry experiment that was reproducible, but only when you used unreactive plastic antibumping granules in the mix. The granules should not have interacted at all with experiment. It turns out that the way that the granules moved stirred up the mixture in a particular way, triggering the reaction. If that detail hadn't been realised by the original experimenter; then the experiment would have been nigh on impossible to replicate.
Still, many things bother me here- the effect that is claimed is small, only 2%; it turns out that weight reductions are often difficult to measure (a lot of machines produce vibrations that make most balances read either high or low- and you can get air currents, thermal effects, magnetic forces, electrostatic forces- all of which are nothing to do with gravity, all of which make weight readings high or low.) And the fact that so many labs cannot reproduce this- that is not a good thing.
Call a code inspection. They're all invited. They do not have to compile it to hold a code inspection.
Compare the code against the requirements and coding standards (if you have any; if not GET SOME). Read through their code line by line. Point out any actual mistakes or violation of the coding standards, and write them down. DO NOT COMPLAIN ABOUT ANYTHING THAT WORKS BUT ISN'T THE WAY YOU WOULD HAVE DONE IT.
Check that the list of problems are fixed. Start integrating...
If its a matter of training, motivation or knowledge, then that's something that might be fixed; but may not be fixed in time.
If they just CAN'T do the work for any reason including training, motivation or knowledge, then you need everyone to be clear about what the situation is, and get them kicked out/off of this project; you probably can't do 3 other persons work for them.
There might be ways to reorganise yourselves that might work. For example can they unit/integration test the code you've written, write test specifications etc?
However, I think your project is going to be late... Some projects (more projects than you might expect) can survive being late. Now is the time to start informing any customers you have...
better start with the internal customers, e.g. the managers.
any optical engineers in the audience care to comment on the likelihood of these accidental reflections causing blindness?
100%. I work with 3-10 milliwatt telecom lasers- and they can blind, although they don't if you stay atleast arms length away. (Diffraction makes them spread out very quickly.)
100KW lasers are 10 million times more powerful...
These may start to remove small portions of your vision if you view a reflection up to a kilometer away; but mostly you'd have to be closer than that. If you were right next to something that was hit, I doubt you'd ever see again one way or another.
"Only three as much money for 10 times the bandwidth, sir?" Never mind that it doesn't cost the company as much as they claim it to (in the case of cable).
It does cost the company quite a bit. A raw feed of a megabit/s costs hundreds of dollars a month or so. Now, in theory that would mean that you'd have to pay that. In practice they assume a particular contention ratio (I get 50:1, commercial packages are more like 20:1), so I only cost them 1/50 of that hundreds of dollars a month, because 49 seconds out of every 50 my connection is idle on average. But it still goes into the tens of dollars range, and they may charge 50 dollars or something. This isn't a case where they make an order of magnitude profit- the profit margins are not that huge. Your analogy is way off.
Good point. An air-breathing launch vehicle is going to have a fairly high dry weight. It could be compensated for by not trying to get to orbit in one stage. The scramjet powered plane would just carry a rocket up to launch altitude and then fly home. The rocket alone would achieve orbit.
Yeah, that can work. But then you've got a two stage rocket; which is messier. Anyway they already do that- with a normal jet- the Pegasus launch vehicle carries a rocket up and then fires it from there.
About your cheap fuel point, you're missing the problem of weight.
That's mainly an issue with ground handling I think.
Yes, the fuel is cheap. Getting the fuel to 100,000 feet with a rocket is not cheap.
Actually it probably is, it mostly just costs fuel, but fuel is cheap.
Rockets are not the most efficient propulsion system.
Thermodynamically a rocket is the most efficient propulsion system. It can turn practically all of the energy in the fuel into fast moving fluid flow. It's more efficient than jets because it runs at incredibly high temperatures. However, jet engines can get more total thrust ('impulse') per unit of fuel because they suck in the oxygen from the atmosphere. If you count that in; Jets are less efficient in fact.
I'm not an expert. If you are, I'll concede the point.
It's not that the idea is silly, it's just that the constraints on it are tight enough that nobody has managed to get it to work well.
Well, liquid hydrogen costs about $5/kg. You need much less than 30 kg to launch 1kg of payload. (2.2 pounds to the kg btw). You do the maths. And incidentally, hydrogen is pretty expensive. LOX is under 4c per kg, and kerosene is not much more than LOX. The fuel is totally negligable.
Your numbers are a bit off BTW. The cost to launch a man is generally reckoned to be about $10,000 per kg. The russians charge less than $20 million, basically because they can. Their whole rocket costs about $5 million. There's a big difference between cost and price...
The real cost goes into the salaries of the employees. There's about 10,000 or more involved with the Space Shuttle. But don't get the impression that the Russian rockets are cheaper just because the Russians are paid a lot less- they are, that's a big factor, but the way they put their rockets together is more efficient as well. NASA don't seem to care about low cost in quite the same way.
Please don't mention the external tank... it gives me a headache just thinking about that much waste.
Most of the fuel burnt to get a space craft into space is burnt in the first 100,000 feet of altitude. If you could fly to this altitude (and get to Mach 5+) and then use a small rocket engine to take you the rest of the way you are going to save *a lot* of money.
Probably not. The problem is you need extra equipment to breath the air- and you carry that all the way to orbit. It turns out that's really critical- you gain most of your speed as the tank is running out (because your fuel level is low and the vehicle is really light then, so you get better acceleration per unit of fuel at that point). And you're in a vacuum, so this equipment doesn't help at all at that point.
Adding in extra mass for airbreathing means that the latter part of the launch is messed up- and so the designs to do this have not succeeded well- they end up using more fuel not less, and/or the payload ends up being really tiny.
Also, you're probably solving the wrong problem- the fuel is less than 1% of the cost of building and launching a space vehicle.
We've all heard talk of over-built data networks and "dark fiber". What interests me is how this apparent over-capacity does not seem to match up the price of bandwidth and the apparent bandwidth management of consumer-level heavy users.
I think what happened a few years ago was that the price was pushed below the sustainable level by VCs indirectly financing your bandwidth. For a couple of years I had a deal that actually cost me nothing whatsoever for my internet connection; actually it saved me 10% of my telephone line rental as well.
What's happened now is the VCs have gone away and the price has bounced back to where it really should have been in the first place and the companies supplying bandwidth are turning a profit again. For companies profit is like breathing- you can hold your breath for only so long and then you die; the companies are breathing again; but looks like some held their breath for too long.
However the cost per bit is going down all the time, and we should gradually see the price that we pay come down with it. (Should being the key part of that sentence;-)
Well, the whole point of asymmetric encryption is that you do use non-reversable encryption methods.
Sorry, that's not right. An asymmetric encryption is still reversible- it has to be- that's how you decrypt it!
'Asymmetric encryption' just means that given one key you can't figure out the other key and vice versa. Symmetric means you can - the keys are related in some usually trivial way- like they're the same, or backwards or something.
Of course, with any encryption system knowing how a frame looks both before and after encryption is a massive bonus for any would-be cracker of encryption codes...
Yes. But when you design codes it's usual to assume a 'known plaintext'; and then design the code to deal with this. A more difficult test still is 'chosen plaintext', where the bad guy get's to give your encyption module a bunch of data and look at the results; and from that tries to work out the key.
As a rule of thumb, unless the module can stand a chosen plaintext attack, I wouldn't touch it with a barge pole.
If the US-based ISP determines that the Italian policemen have hacked into the web account (and they've already admitted it), will they be restoring the web pages from backup tape then;-)
Blue Gravity's chief executive, Tom Krwawecz, said the company was never informed. And he believes U.S. laws -- not Italy's -- ought to apply.
Is Blue Gravity claiming ownership of the contents of the web-site?
Doubt it, that's copyright the author, under international law. But if the Italian police have violated US law, then, bearing in mind the Italian police have admitted they hacked the account, are Blue Gravity going to be restoring the web pages from backup tape?;-)
Slashdot Mirror
And these phones are usually obtained via violence, often to children who almost uniformly carry these for safety reasons; and then get mugged.
As other posters have pointed out- there are whole industries out there, that currently are reasonably legal, that exist solely to make these changes to phones. That cannot be a good thing.
If you want to hack your own phone- frankly, the chances of getting caught are really tiny- go ahead knock yourself out.
you could just make stealing the phone punshiable by 10 years.
Probably not as good; but might work. The young thugs that do the stealing probably aren't the ones that do the reprocessing.
a) you stole the phone
b) you reprogrammed it
If stealing phones gets you stuck inside for 5 years, and reprogramming these phones gets you another 5, I think that thieves may well consider doing something else instead.
google cache You'll see the cost per kg of liquid hydrogen was $2.60 in 1980. I expect it has gone up since then, but not so very much; and it does vary a bit- e.g. if you order enough hydrogen the price goes down.
The Space Shuttle's main tank contains 101 tonnes of liquid hydrogen. Assuming a price of $5/kg, that's $505,000 worth of hydrogen (since there are 1000kg to the tonne). Right?
The cost of adding an extra Space Shuttle to the yearly launch manifest is about $200 million.
Congratulations, you have just learnt something!
Oh yeah the Space Shuttle also burns 606 tonnes of LOX. LOX costs vary, but they are typically a few cents per kg. You can multiply that up if you wish, but the costs are more than 10x less than the hydrogen.
Since the flywheels are going to be in the station, not the train; not a lot.
Batteries are heavier. Still, they didn't actually say AFAIK, but I think that they were planning to put the flywheels in the station, not on the train; so the weight doesn't matter much. It may be that the flywheels are cheaper than the batteries, and they only have to store the energy for a short time in this case anyway- so it's a perfect application.
Yes, just like tuning in a radio. They call that 'frequency division multiplexing'.
I can imagine it's kind of like multithreading but with air waves, every one would get it's slice once in while.
Yes, just like the internet. They call that 'time division multiplexing'. That's used too. There's also 'spatial multiplexing' where each user would use a directional aerial, so that two people could send at the same time and the same frequency but they wouldn't interfere because each aerial would be pointing in a different direction.
My question thereof is this. How does one calculates bandwith available over a given frequency?
There's Shannons law which tells you how much bandwidth you would get, but it depends on the amount of noise there is around too.
Actually, it's not a single frequency- it's over a range of frequencies; you can't get any information sent exactly at 100 Mhz, but you can fit it in from 100-105 Mhz... the number of bits per second you'll manage will depend on the amount of noise drowning you out.
It makes a difference too. The users on the wireless network often have tunneling software to get to the intranet. If they get hacked, then your security may be toast.
Still, a good firewall on each of the wireless users might work... maybe.
It's icy asteroids outside the icing point of the sun- at that distance water is in the form of ice and sublimes only over enormous timescales.
Water is an okish fuel for rockets- the ISP of steam is about 190 seconds, just under half the thrust of the space shuttle main engines, even if you don't split it into hydrogen and oxygen.
Basically, if you can reach that, the whole solar system is open to you- so much fuel you wouldn't know which way to go first...
In its simplest form rocket engine has no moving parts either (ok, there's usually a few valves, but scramjet would need them also.)
The Space Shuttle Main Engines have complicated turbopumps, but I wouldn't exactly hold that up as a shining example of rocket engineering; but the SRBs don't have any moving parts.
ISP is not everything- it's recently been realised that fuels that have lower ISP can give more payload to orbit than hydrogen/LOX. Reaching orbit is much more subtle than you would expect. Scramjets actually look like a bad idea for reaching orbit; they're too heavy- but may be good for a first stage, where the weight doesn't matter nearly so much.
Hint: 11.2 km/s is escape velocity (mach 25 or so).
So 133km/s would be more than mach 250 ;-)
I've personally found it easier to achieve in languages other than C/C++; Java is better for this. The point is that C/C++ ramp up the care required rather significantly- dereferencing pointers/variation in the compiler/automagic casts/crashes rather than tracebacks- all these things and more do not make for a pleasant programming experience, and that usually kicks me out- as soon as you're going "what the f**k caused that?"- and hunting around for more data- you're probably gone.
Still some debugging environments are much better than others, but I work in embedded systems- where the environments often suck and suck badly.
Still, if you do manage to get in the flow in these languages, then more power to you, your error rate will go way down, and you need more or less zero error rate in many tasks for C/C++.
However, it may be that they did something wrong- perhaps some detail was performed incorrectly, or something. It does happen sometimes. As a similar, but not exact example, I once heard about a chemistry experiment that was reproducible, but only when you used unreactive plastic antibumping granules in the mix. The granules should not have interacted at all with experiment. It turns out that the way that the granules moved stirred up the mixture in a particular way, triggering the reaction. If that detail hadn't been realised by the original experimenter; then the experiment would have been nigh on impossible to replicate.
Still, many things bother me here- the effect that is claimed is small, only 2%; it turns out that weight reductions are often difficult to measure (a lot of machines produce vibrations that make most balances read either high or low- and you can get air currents, thermal effects, magnetic forces, electrostatic forces- all of which are nothing to do with gravity, all of which make weight readings high or low.) And the fact that so many labs cannot reproduce this- that is not a good thing.
Compare the code against the requirements and coding standards (if you have any; if not GET SOME). Read through their code line by line. Point out any actual mistakes or violation of the coding standards, and write them down. DO NOT COMPLAIN ABOUT ANYTHING THAT WORKS BUT ISN'T THE WAY YOU WOULD HAVE DONE IT.
Check that the list of problems are fixed. Start integrating...
If they just CAN'T do the work for any reason including training, motivation or knowledge, then you need everyone to be clear about what the situation is, and get them kicked out/off of this project; you probably can't do 3 other persons work for them.
There might be ways to reorganise yourselves that might work. For example can they unit/integration test the code you've written, write test specifications etc?
However, I think your project is going to be late... Some projects (more projects than you might expect) can survive being late. Now is the time to start informing any customers you have... better start with the internal customers, e.g. the managers.
100%. I work with 3-10 milliwatt telecom lasers- and they can blind, although they don't if you stay atleast arms length away. (Diffraction makes them spread out very quickly.)
100KW lasers are 10 million times more powerful...
These may start to remove small portions of your vision if you view a reflection up to a kilometer away; but mostly you'd have to be closer than that. If you were right next to something that was hit, I doubt you'd ever see again one way or another.
It does cost the company quite a bit. A raw feed of a megabit/s costs hundreds of dollars a month or so. Now, in theory that would mean that you'd have to pay that. In practice they assume a particular contention ratio (I get 50:1, commercial packages are more like 20:1), so I only cost them 1/50 of that hundreds of dollars a month, because 49 seconds out of every 50 my connection is idle on average. But it still goes into the tens of dollars range, and they may charge 50 dollars or something. This isn't a case where they make an order of magnitude profit- the profit margins are not that huge. Your analogy is way off.
Yeah, that can work. But then you've got a two stage rocket; which is messier. Anyway they already do that- with a normal jet- the Pegasus launch vehicle carries a rocket up and then fires it from there.
About your cheap fuel point, you're missing the problem of weight.
That's mainly an issue with ground handling I think.
Yes, the fuel is cheap. Getting the fuel to 100,000 feet with a rocket is not cheap.
Actually it probably is, it mostly just costs fuel, but fuel is cheap.
Rockets are not the most efficient propulsion system.
Thermodynamically a rocket is the most efficient propulsion system. It can turn practically all of the energy in the fuel into fast moving fluid flow. It's more efficient than jets because it runs at incredibly high temperatures. However, jet engines can get more total thrust ('impulse') per unit of fuel because they suck in the oxygen from the atmosphere. If you count that in; Jets are less efficient in fact.
I'm not an expert. If you are, I'll concede the point.
It's not that the idea is silly, it's just that the constraints on it are tight enough that nobody has managed to get it to work well.
Your numbers are a bit off BTW. The cost to launch a man is generally reckoned to be about $10,000 per kg. The russians charge less than $20 million, basically because they can. Their whole rocket costs about $5 million. There's a big difference between cost and price...
The real cost goes into the salaries of the employees. There's about 10,000 or more involved with the Space Shuttle. But don't get the impression that the Russian rockets are cheaper just because the Russians are paid a lot less- they are, that's a big factor, but the way they put their rockets together is more efficient as well. NASA don't seem to care about low cost in quite the same way.
Please don't mention the external tank... it gives me a headache just thinking about that much waste.
SLI? Hah!
Probably not. The problem is you need extra equipment to breath the air- and you carry that all the way to orbit. It turns out that's really critical- you gain most of your speed as the tank is running out (because your fuel level is low and the vehicle is really light then, so you get better acceleration per unit of fuel at that point). And you're in a vacuum, so this equipment doesn't help at all at that point.
Adding in extra mass for airbreathing means that the latter part of the launch is messed up- and so the designs to do this have not succeeded well- they end up using more fuel not less, and/or the payload ends up being really tiny.
Also, you're probably solving the wrong problem- the fuel is less than 1% of the cost of building and launching a space vehicle.
How exactly do you think they got in those positions in the first place ;-) ?
That's their main qualification!
I think what happened a few years ago was that the price was pushed below the sustainable level by VCs indirectly financing your bandwidth. For a couple of years I had a deal that actually cost me nothing whatsoever for my internet connection; actually it saved me 10% of my telephone line rental as well.
What's happened now is the VCs have gone away and the price has bounced back to where it really should have been in the first place and the companies supplying bandwidth are turning a profit again. For companies profit is like breathing- you can hold your breath for only so long and then you die; the companies are breathing again; but looks like some held their breath for too long.
However the cost per bit is going down all the time, and we should gradually see the price that we pay come down with it. (Should being the key part of that sentence ;-)
Sorry, that's not right. An asymmetric encryption is still reversible- it has to be- that's how you decrypt it!
'Asymmetric encryption' just means that given one key you can't figure out the other key and vice versa. Symmetric means you can - the keys are related in some usually trivial way- like they're the same, or backwards or something.
Of course, with any encryption system knowing how a frame looks both before and after encryption is a massive bonus for any would-be cracker of encryption codes...
Yes. But when you design codes it's usual to assume a 'known plaintext'; and then design the code to deal with this. A more difficult test still is 'chosen plaintext', where the bad guy get's to give your encyption module a bunch of data and look at the results; and from that tries to work out the key.
As a rule of thumb, unless the module can stand a chosen plaintext attack, I wouldn't touch it with a barge pole.
Is Blue Gravity claiming ownership of the contents of the web-site?
Doubt it, that's copyright the author, under international law. But if the Italian police have violated US law, then, bearing in mind the Italian police have admitted they hacked the account, are Blue Gravity going to be restoring the web pages from backup tape? ;-)
Huh? A figure isn't scientific unless it has an attached standard deviation. Last digit an estimate? Where's that written?