One possible explanation is that earth-based life made it to radio-emitting civilization the fastest as possible, and no other civilization elsewhere made it sooner enough so that we could see their radio emission.
The time a civilization spends with radio level technology may be very brief before technological extinction. The same internecine conflict which leads to easy to detect military radar also leads to war.
The species does not have to drive itself extinct; it just has to lose radio level of technology.
Our technology is to the point where we could prevent a recurrence of the Great Dying.
But our politics are not. We cannot even more beyond election systems which encourage insincere voting.
Professor Bernard Quatermass: The will to survive is an odd phenomenon. Roney, if we found out our own world was doomed, say by climatic changes, what would we do about it? Dr. Mathew Roney: Nothing, just go on squabbling like usual.
I have not seen any evidence of that however the NSA did control the IPSEC committee and took steps to make sure IPSEC in the form of ubiquitous opportunistic encryption would not be adopted.
Correct me if I'm mistaken, but isn't tuning into an RF freq essentially just a form of induction. Meaning, the moment you tune into that frequency, the minute energy captured is also putting a load on the transmitter. So, if everyone in a city tuned into an AM radio station at the same time, there would be a significant draw on the antenna until people tuned off the channel. If so, the energy isn't "free" in a since of being ambient; somebody is paying for that electricity.
No, it is not the same thing in induction. Induction relies on magnetic coupling which decreases following the cube law. Electromagnetic coupling decreases following the square law.
Coupling between the receive antenna and transmit antenna in the near field zone could have an effect which is how parasitic antenna elements work but in this case, the energy from the transmitter is already lost in the far field and the transmitter sees no change. If the receiver had a large enough capture area, and capture area is a major limitation which will never allow this to work except in the most trivial applications, then it could cause a shadow but the transmitter would not see it.
On the other hand, GPS signals are spread spectrum, with significant FEC and error correction in them. From what I understand, most GPS jammers work by overwhelming the radio front-end, rather than by masking the original signal. If you were to replace the omni-directional antenna that is normally used for GPS with a directional one and aim it at the sky, that would go a long way to reduce the effectiveness of a jammer.
It is more like the radio back end. Commercial GPS receivers use 1 bit direct conversion which works fine but provides poor resistance to jamming. The GPS signal starts out below the noise floor and is still weak after despreading. There is no need to overload the RF amplifier or mixer.
Antennas which have less gain toward the horizon help if that is where the jamming source is but also mask satellites. In a city this does not help because reflections from the jammer will be overhead.
Implementing various anti-jamming measures is restricted by law. Commercial GPS receivers are *suppose* to be easy to jam.
Why were the NSA spying on someone who was possibly involved in copyright infringement? Why was the GCSB assisting the NSA in spying on someone who was possibly involved in copyright infringement?
The NSA spies on American citizens and forwards the information to the DEA and other law enforcement agencies for drug and other crimes. Why wouldn't they get involved in copyright infringement?
There actually *is* some real hardware. Take any ADCs and chop off 1 or more of the most significant bits. Poof! Now you have an ADC which produces a well defined and characterized modulo output albeit with a lower resolution and input signal range.
Or you could keep the bits and forget the whole reconstruction thing. It could still be useful for recovering data from communication channels where the most significant bits are corrupted.
Folding type ADCs have been around as practical implementation since at least 1970s and while they do what the authors want, the folding process is internal so they saturate just like most other ADCs. Support for external folding means adding another stage (or increasing the resolution of an existing stage) to increase the resolution of the ADC and if you are going to do that, why not just accept the full resolution instead of throwing bits away and trying to reconstruct the input? Modern and ubiquitous pipeline ADCs use folding internally.
Run up integrating ADCs can do exactly what the authors want however their low speed makes them unsuitable for any of the applications the authors have in mind. These days they are only found in the highest resolution and accuracy applications like 7 and 8 digit test instruments.
I admit that I don't understand their algorithm, however they were able to reconstruct a random signal with a maximum amplitude exceeding 20 times the ADC upper bound. The mean squared error between the original and constructed signals was 1.5 x 10^-33.
If we assume a perfectly spherical ADC in a vacuum, then sure. But in reality, the folding process compromises the accuracy of the converter so no additional resolution becomes available. Beyond a certain point, errors accumulate so accuracy goes down. There is a reason folding ADCs do not achieve the highest resolutions.
Why not make a wide dynamic range converter with a non-linear transfer function? They have been used before to good effect in voice audio applications.
Maybe a magic self-reset converter has been developed but none of the papers they cite which I have access to discuss such a thing. The systems discussed instead effectively implement a run-up integrating converter with integration happening after sampling in the digital domain and if you are going to do that, why throw away the extra resolution just so the signal needs to be reconstructed?
The method described in the paper would be useful where folding occurs after digitizing to fit excess resolution into a narrow interface but with increasing bandwidth and memory storage, is that a real problem?
Are you sure shining a laser on something already designed to withstand unthinkable heat wouldn't be more like threatening the devil with a match?
That would be the case for an ballistic reentry vehicle or a hypersonic cruise missile relying on satellite and inertial navigation but ships move. How does terminal guidance on a hypersonic missile work? The forward surfaces have to be both heat resistant and permeable to whatever sensor is used. The front cannot be just a titanium dart.
Further you can count on laser power to increase significantly once this sort of anti-missile defense is deemed necessary now that a low power version is being tested in the field and newer ship designs are taking this into account already.
Lasers may create *coherent* beams and most of them do not even do that because only specialized applications like holography and Interferometry need coherence. Lasers not specifically designed to produce a coherent beam have a typical coherence length of millimeters to centimeters as I discovered when trying to build an Interferometer.
With even consumer grade optics, distance by itself has no effect on power.
Ordinary observation of a consumer or lab grade laser over moderate distances will show that the beam does obey the square law rule past a relatively short distance from the aperture. I have done it myself.
Aimed at a crowd this weapon could certainly be classed as indiscriminate.
Not just indiscriminate, you may not notice you're being targeted until people around you start boiling.
As if hellfire missiles at weddings isn't enough, now there will be no signature whatsoever who did the deed.
It's quite likely that the number of incidents of spontaneous human combustion will go drastically up in the coming years
How is this different than a firearm and especially a rifle at long range where targets will be struck considerably before the report is heard. How is it different from artillery?
That's not a problem if your QoS settings are evaluated against only your traffic. In other words, if you mark all of your packets high-priority, none of them really will be because they're all in the same priority queue. If implemented properly, the only one you can screw is yourself.
But where are the rent seeking possibilities in that?
I don't think it will make any difference whether they used their real names or not. If they used an offshore VPN they might have a chance, but never underestimate the resourcefulness of government investigators. It's a lot harder to be anonymous on the Internet than you might think.
It is trivial if you use an open WiFi hotspot; at best that will give them your general location. If you are paranoid then in addition, forge your MAC address and use a separate browser inside of an encrypted VM.
In fact, I've seen it take a minute or two to get a lock, and even then it keeps chatting with the satellites to narrow down your location.
That was years ago. Most recent android phones take at most 10 sec to get a lock. It helps if the case is not made of metal.
They should be considerably faster than that.
The difference is not in the GPS receiver but in the phone implementing AGPS. A GPS lock requires downloading the ephemeris from each GPS satellite which takes 18 to 36 seconds. A phone using AGPS downloads the ephemeris for each GPS satellite through the network so this delay can be skipped.
In the past a GPS receiver had to download the 12.5 minute long almanac producing considerable delay but modern receivers can do a massive parallel code search for the satellites without it and obviously an AGPS receiver does not care about it.
Because you are not receiving 'a GPS signal'. You are receiving a multitude of GPS and GLONASS signals. From the time stamps and positional information encoded in these signals you then have to calculate your position. All these calculations are time-critical, so I guess they don't combine very well with power saving features.
Why there have beeen tremendous amounts in rendering speeds and all kinds of image processing, but not in the calculation of these GPS coordinates, that is a mystery to me as well.
There *have* been massive improvements in GPS receivers do to increasing integration. The first commercial receivers used a single correlator and time multiplexed it to iteratively monitor each visible satellite. Some modern receivers still support operating this way to conserve power but it is detrimental to GPS performance.
The calculations aren't processor intensive, they're really quite easy. The battery drain is from the radio receivers, which are amped up to distinguish the really weak GPS signal from all the noise with the really small antennas built into the phone.
The first amplification stage is the only one which affects the signal to noise ratio and there is practically nothing to be gained by trying to use a lower noise figure to make up for the lack of antenna gain; the improvement available here is less than 2dB and probably more like 0.3dB with real parts. Increasing the gain after the first stage does not require significant power.
If there are excess power requirements for cell phone GPS receivers, then they are somewhere else. Their antenna performance is horrible leading to poor GPS performance no matter what is done.
But once the USPS was gone, they would offer services.
Yep, just like ISPs provide universal service within their territories. Err, wait... And even with effective monoplies, ISPs cannot be bothered to do this.
There is no rational reason that one group of citizens should subsidize the lifestyle choice of another group.
Universal postal service was originally considered important enough for subsidize to be used to provide a flat rate service. Whether that is the case today can be debated.
Slashdot Mirror
The habit of having a "negative agreement" where you have to check a box and send back if you don't want a service is not legal in some areas.
Just like something being unconstitutional, it is legal if it is not enforced.
One possible explanation is that earth-based life made it to radio-emitting civilization the fastest as possible, and no other civilization elsewhere made it sooner enough so that we could see their radio emission.
The time a civilization spends with radio level technology may be very brief before technological extinction. The same internecine conflict which leads to easy to detect military radar also leads to war.
The species does not have to drive itself extinct; it just has to lose radio level of technology.
Our technology is to the point where we could prevent a recurrence of the Great Dying.
But our politics are not. We cannot even more beyond election systems which encourage insincere voting.
Professor Bernard Quatermass: The will to survive is an odd phenomenon. Roney, if we found out our own world was doomed, say by climatic changes, what would we do about it?
Dr. Mathew Roney: Nothing, just go on squabbling like usual.
I have not seen any evidence of that however the NSA did control the IPSEC committee and took steps to make sure IPSEC in the form of ubiquitous opportunistic encryption would not be adopted.
But we are guaranteed equal opportunity under the constitution.
They are not working toward equal opportunity. They are working toward equal outcome.
The problem is that he basically accused his bosses of being incompetent thought-controlling tyrants, ...
So then they fired him removing all doubt?
Correct me if I'm mistaken, but isn't tuning into an RF freq essentially just a form of induction. Meaning, the moment you tune into that frequency, the minute energy captured is also putting a load on the transmitter. So, if everyone in a city tuned into an AM radio station at the same time, there would be a significant draw on the antenna until people tuned off the channel. If so, the energy isn't "free" in a since of being ambient; somebody is paying for that electricity.
No, it is not the same thing in induction. Induction relies on magnetic coupling which decreases following the cube law. Electromagnetic coupling decreases following the square law.
Coupling between the receive antenna and transmit antenna in the near field zone could have an effect which is how parasitic antenna elements work but in this case, the energy from the transmitter is already lost in the far field and the transmitter sees no change. If the receiver had a large enough capture area, and capture area is a major limitation which will never allow this to work except in the most trivial applications, then it could cause a shadow but the transmitter would not see it.
On the other hand, GPS signals are spread spectrum, with significant FEC and error correction in them. From what I understand, most GPS jammers work by overwhelming the radio front-end, rather than by masking the original signal. If you were to replace the omni-directional antenna that is normally used for GPS with a directional one and aim it at the sky, that would go a long way to reduce the effectiveness of a jammer.
It is more like the radio back end. Commercial GPS receivers use 1 bit direct conversion which works fine but provides poor resistance to jamming. The GPS signal starts out below the noise floor and is still weak after despreading. There is no need to overload the RF amplifier or mixer.
Antennas which have less gain toward the horizon help if that is where the jamming source is but also mask satellites. In a city this does not help because reflections from the jammer will be overhead.
Implementing various anti-jamming measures is restricted by law. Commercial GPS receivers are *suppose* to be easy to jam.
How do you propose to deal with guys like Bernie Madoff then?
Sentence him to be President?
Because the goal of the justice system is supposed to be justice, not vengeance.
Then you have already fallen for it. We have courts of "law" and not courts of "justice". The Department of Justice and Justice System are misnamed.
"Some of the stuff they're doing from a technology perspective is amazing,"
So advanced technology can make it even slower and more of a resource hog?
Why were the NSA spying on someone who was possibly involved in copyright infringement?
Why was the GCSB assisting the NSA in spying on someone who was possibly involved in copyright infringement?
The NSA spies on American citizens and forwards the information to the DEA and other law enforcement agencies for drug and other crimes. Why wouldn't they get involved in copyright infringement?
There actually *is* some real hardware. Take any ADCs and chop off 1 or more of the most significant bits. Poof! Now you have an ADC which produces a well defined and characterized modulo output albeit with a lower resolution and input signal range.
Or you could keep the bits and forget the whole reconstruction thing. It could still be useful for recovering data from communication channels where the most significant bits are corrupted.
Folding type ADCs have been around as practical implementation since at least 1970s and while they do what the authors want, the folding process is internal so they saturate just like most other ADCs. Support for external folding means adding another stage (or increasing the resolution of an existing stage) to increase the resolution of the ADC and if you are going to do that, why not just accept the full resolution instead of throwing bits away and trying to reconstruct the input? Modern and ubiquitous pipeline ADCs use folding internally.
Run up integrating ADCs can do exactly what the authors want however their low speed makes them unsuitable for any of the applications the authors have in mind. These days they are only found in the highest resolution and accuracy applications like 7 and 8 digit test instruments.
I admit that I don't understand their algorithm, however they were able to reconstruct a random signal with a maximum amplitude exceeding 20 times the ADC upper bound. The mean squared error between the original and constructed signals was 1.5 x 10^-33.
If we assume a perfectly spherical ADC in a vacuum, then sure. But in reality, the folding process compromises the accuracy of the converter so no additional resolution becomes available. Beyond a certain point, errors accumulate so accuracy goes down. There is a reason folding ADCs do not achieve the highest resolutions.
Why not make a wide dynamic range converter with a non-linear transfer function? They have been used before to good effect in voice audio applications.
Maybe a magic self-reset converter has been developed but none of the papers they cite which I have access to discuss such a thing. The systems discussed instead effectively implement a run-up integrating converter with integration happening after sampling in the digital domain and if you are going to do that, why throw away the extra resolution just so the signal needs to be reconstructed?
The method described in the paper would be useful where folding occurs after digitizing to fit excess resolution into a narrow interface but with increasing bandwidth and memory storage, is that a real problem?
Are you sure shining a laser on something already designed to withstand unthinkable heat wouldn't be more like threatening the devil with a match?
That would be the case for an ballistic reentry vehicle or a hypersonic cruise missile relying on satellite and inertial navigation but ships move. How does terminal guidance on a hypersonic missile work? The forward surfaces have to be both heat resistant and permeable to whatever sensor is used. The front cannot be just a titanium dart.
Further you can count on laser power to increase significantly once this sort of anti-missile defense is deemed necessary now that a low power version is being tested in the field and newer ship designs are taking this into account already.
Lasers create cohesive beams.
Lasers may create *coherent* beams and most of them do not even do that because only specialized applications like holography and Interferometry need coherence. Lasers not specifically designed to produce a coherent beam have a typical coherence length of millimeters to centimeters as I discovered when trying to build an Interferometer.
With even consumer grade optics, distance by itself has no effect on power.
Ordinary observation of a consumer or lab grade laser over moderate distances will show that the beam does obey the square law rule past a relatively short distance from the aperture. I have done it myself.
https://www.quora.com/Is-the-l...
re 'The energy of the "shot" delivered should drop with the square of the distance from the target.'
It's a laser! The energy of the shot will not follow an inverse square law - it will dissipate slowly due to slight incoherence and absorption.
It certainly does follow the inverse square law and you can observe this yourself with any common laser.
https://www.quora.com/Is-the-l...
It is not a blinding weapon. It is a killing weapon and any blindness that is causes is secondary to its intended use.
Aimed at a crowd this weapon could certainly be classed as indiscriminate.
Not just indiscriminate, you may not notice you're being targeted until people around you start boiling.
As if hellfire missiles at weddings isn't enough, now there will be no signature whatsoever who did the deed.
It's quite likely that the number of incidents of spontaneous human combustion will go drastically up in the coming years
How is this different than a firearm and especially a rifle at long range where targets will be struck considerably before the report is heard. How is it different from artillery?
Problem is that's a system which relies on trust.
That's not a problem if your QoS settings are evaluated against only your traffic. In other words, if you mark all of your packets high-priority, none of them really will be because they're all in the same priority queue. If implemented properly, the only one you can screw is yourself.
But where are the rent seeking possibilities in that?
I don't think it will make any difference whether they used their real names or not. If they used an offshore VPN they might have a chance, but never underestimate the resourcefulness of government investigators. It's a lot harder to be anonymous on the Internet than you might think.
It is trivial if you use an open WiFi hotspot; at best that will give them your general location. If you are paranoid then in addition, forge your MAC address and use a separate browser inside of an encrypted VM.
In fact, I've seen it take a minute or two to get a lock, and even then it keeps chatting with the satellites to narrow down your location.
That was years ago. Most recent android phones take at most 10 sec to get a lock. It helps if the case is not made of metal.
They should be considerably faster than that.
The difference is not in the GPS receiver but in the phone implementing AGPS. A GPS lock requires downloading the ephemeris from each GPS satellite which takes 18 to 36 seconds. A phone using AGPS downloads the ephemeris for each GPS satellite through the network so this delay can be skipped.
In the past a GPS receiver had to download the 12.5 minute long almanac producing considerable delay but modern receivers can do a massive parallel code search for the satellites without it and obviously an AGPS receiver does not care about it.
Because you are not receiving 'a GPS signal'. You are receiving a multitude of GPS and GLONASS signals. From the time stamps and positional information encoded in these signals you then have to calculate your position. All these calculations are time-critical, so I guess they don't combine very well with power saving features.
Why there have beeen tremendous amounts in rendering speeds and all kinds of image processing, but not in the calculation of these GPS coordinates, that is a mystery to me as well.
There *have* been massive improvements in GPS receivers do to increasing integration. The first commercial receivers used a single correlator and time multiplexed it to iteratively monitor each visible satellite. Some modern receivers still support operating this way to conserve power but it is detrimental to GPS performance.
The calculations aren't processor intensive, they're really quite easy. The battery drain is from the radio receivers, which are amped up to distinguish the really weak GPS signal from all the noise with the really small antennas built into the phone.
The first amplification stage is the only one which affects the signal to noise ratio and there is practically nothing to be gained by trying to use a lower noise figure to make up for the lack of antenna gain; the improvement available here is less than 2dB and probably more like 0.3dB with real parts. Increasing the gain after the first stage does not require significant power.
If there are excess power requirements for cell phone GPS receivers, then they are somewhere else. Their antenna performance is horrible leading to poor GPS performance no matter what is done.
But once the USPS was gone, they would offer services.
Yep, just like ISPs provide universal service within their territories. Err, wait ... And even with effective monoplies, ISPs cannot be bothered to do this.
There is no rational reason that one group of citizens should subsidize the lifestyle choice of another group.
Universal postal service was originally considered important enough for subsidize to be used to provide a flat rate service. Whether that is the case today can be debated.