I wonder what the best way to get these small doses might be.
Dunno, but I find that chunks of 70+% bitter chocolate at regular intervals (every half hour or so) seems to keep me awake till the well after dawn when I play FPS's. Then again, I guess the FPS itself is stressful, so would tend to prolong wakefullness, but still, the chocolate seems to do something.
There's Caffeine, as well as other stimulants (theobromine IRC) in chocolate, so it's not too surprising I guess.
Yes, it's a sensible thing to do with a cash prize. It's probably not done with things like cars because the company offering the prize probably got it free from the manufacturer, and the prize givers can't easily pony up the extra money to cover the tax.
IIRC, when someone else pays your taxes for you, it's considered taxable income.
Sure, but the series converges, so if you pay 10% tax, the company could pay 1/9 of the value of the item to the tax man and they would be happy (0.10 + 0.01 + 0.001 + 0.0001 +... = 0.111111' = 1/9).
You know, most of the antennas I've built, including the phased array for fox hunting, work quite well.
Yes, I expect it was fixed phase shift, which is correct for that- for a physically steered antenna. That says nothing about the general case of phased element array, which includes active elements with electronic phase shifting; the plasma reflector is an example of that. That's how you can arrange for electronic streering.
But neither of them are securing the wireless part of your network.
Correct! I wasn't protecting the wireless part of the network, as you more or less cannot (short of Tempest shielding). I was protecting corporate data. As a rule of thumb anyone can use the airwaves under FCC rules. I did make very sure that the wireless network didn't provide internet access, or any other services; so whilst outsiders ('Eve') could in theory have connected to the Wireless LAN from outside the building (difficult since the building was a weak approximation to a Faraday cage, but possible with an antenna of high enough gain), it wouldn't really do 'Eve' much good. The only exception was a direct attack on the clients themselves- I deployed personal firewalls for those; and the security turned out to be the same or better than when the same clients were connected to corporate LAN over the internet.
Ok, this is the last time:
You've several times explained how you can get range from triangulation, while calling it phase, but NOT from just knowing the phase of the signal.
The phase difference between the signal received at the middle of an antenna from either side of the antenna is slightly different from a nearby spherical source to that of a spherical source at infinity (plane wave). The wider the antenna is, the bigger the effect. You need a big antenna, but it can be flat and out the way- up against a wall for example. I simply can't be bothered to explain how you can do this- if you don't believe it can be done, or it's too complex.
This calculation has nothing to do with phase. It's only the signal strength that matters here.
Utter coddswallop. Neither the receive, nor transmit function works unless you have correct phase shift at each emitter. That's the whole point of a phased array. That's where the name "phased element array" comes from. If you have no phase shift then your antenna will work extremely poorly if at all.
No, it has become clear to me that you fundamentally don't understand phased arrays in general.
I've actually (in a past life so to speak) been tasked with helping secure a wireless network in an office environment. The solution was A: Encryption. B: Multiple AP's spread to give good coverage of the building's interior with any overlap well inside the perimiter. C: Very careful antenna selection to provide optimal coverage inside, with minimal sensitivity outside the building. D: MAC address filtering (which helps a little, but is still easy to bypass) E: Other stuff I'm not going to talk about here.
Yeah? So have I. The answer was: firewalls + corporate standard VPN. In your case I certainly hope your encryption wasn't WEP, but I don't particularly care; it sounds ghastly.
Well, you're assuming that wired is secure- unless you're using Tempest shielding evesdropping is reasonably easy even with wired.
Basically security isn't all or nothing, ever.
In this case, forbidding/ignoring traffic from outside a configured physical perimeter would indeed result in more security for the network in many cases- it prevents people from injecting traffic to your network as well as improving throughput.
it should be marginally more efficient - and more accurate - to use separate arrays a fixed distance apart instead of running focusing calculations.
I think having multiple arrays scattered around the place is a very good idea anyway. The nice thing about this focusing trick is that they don't need to be phased together, since they independently can calculate distance. Having multiple arrays allows triangulation, and minimises the chances of the base station and clients lining up; which is likely to be the worst case.
Antenna's, in of themselves, don't have phase.
It's probably not normally considered like that, but different parts of any antenna are at a different phase; they have a formally linear response to a wave, right?
For a phased array, you can consider each 'active' element of a phased array to have a complex number that is multiplied by the signal that is measured at that point. The output of the array is the sum of these numbers. That forms a spatial filter. By calculating the complex number based on the speed of light delay you can (theoretically) focus the array onto a particular point in space by adjusting the phase/amplification in that way. The maths is trivial; in principle.
That gives you a bearing, yes. The larger the aperature of your array, the more accurate your bearing will be. Unless your array is large enough (and has enough elements) to get multiple relative bearings on the same source, you're not going to get a range simply from the signal's phase.
That's not correct. The analogy is not exact, but that's approximately the way GPS works.
It's just like focusing in the optical domain- you can focus a phased array a fixed distance away, rather than at infinity.
You seem to be thinking that the phased array can only focus at infinity, but that is not in fact the case, and focusing it at the appropriate distance gives more discrimination for the antenna.
Note that some of the theory behind synthetic aperture assumes focusing at infinity, but for a few elements at close proximity, it's not at all hard, or computationally intensive, to calculate the appropriate phasing.
Going back to the original topic, it's unclear whether this would be 'secure'- it's theoretically possible to arrange for the signals that arrive at the antenna to have the same phase as an antenna that is close to the array but from further away, but it's a whole heap of hassle and unlikely to be practical in most cases.
It's a reflective diffraction grating you can change on the fly. It de/reflects the signal back into a detector. It's not particularly exotic.
It's decidedly more exotic than the 18 element Yagi I've used for 2.4 gig work, or the 5 element phased array I've used fox hunting.
You still seem to be missing the point- this system is electronically steerable. Sure there are other ways to do that with switchable antennas, or physical steering, but this is another way.
This technique does not give a range. Only a direction.
It certainly can do; when the antenna subtends a large angle to the client; the point is that the phase at the elements of the antenna is not uniform across the antenna for the relatively small distances typically seen in WiFi.
My point is that your base station will have to consume X power for the RF section, and Y power for the processing section regardless of antenna type. A plasma antenna will add Z power to drive the plasma generator which strikes me as being considerably more power hungry than the X+Y power of existing base stations.
Yes, but with normal phased array, you need other switcheable electronics to introduce phase delays on the signal which you don't need here; they may well be expensive, and will consume power as well. I expect you are correct that the plasma solution is more power hungry, although I'd need to check. But in any case I'm quite unclear that power is a bottleneck for this application in most circumstances. I mean, a PC is taking 300 watts, and laptops are perhaps 60 watts; unless you are talking kilowatts, it probably goes in the 'who cares' category.
Base stations would be the logical place to use these things, yes, but how is it going to work out the range?
If you think about it, the wavefront from the trasnmitter has to hit the different parts of the antenna at the 'right' time- it's critically phase dependent- the wavelength of 2.5Ghz is about 15cm, so you can measure the distance to within a fraction of that.
Basically the bigger the antenna is, the further away you can distinguish the distance. In a fairly real sense you are doing triangulation/timing analysis independently from different sides of the antenna. It's exactly like focusing through a parabolic mirror in the optical domain.
Without detail I can't confirm it, but I suspect there's considerably more power going into ionizing the "antenna" than is going into radiating signal. That's just wasteful.
Not really. The radio power is limited by the FCC, but the base station power isn't. I mean, flourescents aren't particularly thirsty- and you only need a very small flourescent for this kind of thing.
First, we can get the same effect with a physical antenna array.
That's much more complex, notionally, it requires microwave frequency digital signal processing; the reflector system lets the antenna act as a spatial directional filter without any further processing.
It doesn't require an exotic plasma antenna (which still looks like a reflector to me from the pics, not a radiator) to tell which direction your users lay.
It's a reflective diffraction grating you can change on the fly. It de/reflects the signal back into a detector. It's not particularly exotic.
And you'll only realize a bandwidth advantage if the remote signals don't interfear with each other - which would requre them to also be highly directional, which brings us back to trying to get these things working on a portable device.
No, because the portable devices effectively have huge big directional virtual antennas pointed at them- so both send and receive are improved- only if the clients are very close together will there be problems.
Also remember you're limited by the processing power of the base station itself, and the inherent limitations of available bandwidth on any given freq.
The base station doesn't need much in the way of signal processing with this scheme- the filters can even be precalculated if necessary.
It certainly seems like a cool technology, but I'm not sure how it would apply to WiFi - or even Ham for that matter. Yes, a tight beam antenna will provide some slight level of added security (while not substituting for encryption)
Well, I think it's a bit better than that- a base station with this technology can probably work out the distance as well as the angle- the antenna forms a spatially distributed antenna and hence can measure the phase and intensity and show where the user is.
there is the issue of power requirement - you need to create that plasma - fuel requirement - the gas you're ionizing
It's not a problem for a base station though- and that's where I see this technology going.
- and the shielding requirements.
There really aren't any- it's just like a flourescent bulb.
The main advantage of this system is that the highly directional antenna can actually permit two users to use the same bands without interference (since they are distinguished by their location, the base stations would be relatively deaf to any users not associated with them)- this greatly multiplies up the bandwidth of a WIFI network.
I know you're joking, but the BBC/ITV are both being really squeezed by the Murdoch Sky thing- if they can't use the weapons they have available to them, then in the long term questions like: "why do we need the BBC if nobody watches it anyway" could start to resonate a little too well.
I mean, ITV has always had more money than the BBC, but Sky has even more, and can just buy up the most popular shows/sporting events...
If military tech is locked up by secrecy, then it makes the military stronger, but it can't be used by industry. Of course, the same is true of civilian research that's locked up by absurd patents...
It shouldn't be, or atleast it may not be. The one good thing about patents is that you have to publish them, and using the same idea in a different area may well not infringe on the patent (depending on exactly how it is written)
Top secret military stuff just doesn't get published at all.
You can consider that rights ultimately are only really given you by governments.
It's not that ideas are public property- it's that the government wants to encourage the cross fertilisation you get when ideas aren't hidden in the middle of companies and corporations as 'trade secrets'.
So the government invents patents, which protect the idea for a few years (typically 15), but then expire, allowing the idea to be improved upon by others (independent of how bloody minded or wrong headed or just unable to capitalise on the idea that the patent holder may have been).
And as a side benefit, the idea is out there and can be perused, and the concept may be applied to a different area or business not covered by the patent.
So both sides gain- the government gains economic growth, the patent owner gains legal protection for 15 years. It also helps break up the monopolies that can form around some industrial processes- Governments hate competition (they think they should be the only monopoly:) )
So, patents are win-win. That's why they survive. It's nothing theoretically to do with the theory of "rights" or property- it just turns out that the nearest thing to handle this kind of 'ownership' is property law.
They aren't; they are going after some users of some P2P systems. P2P is a very wide area- with lots of protocols- most of the internet is P2P- the IP protocol itself is P2P. USENET especially is P2P.
Because its used mostly for piracy.
No; well maybe. But that's not necessarily true for all P2P or for all time. For example Skype is P2P, but there's presumably little or no piracy going on there.
There is a certain truth to this. I can take a FreeBSD release, alter it and relicense it so that it can't be merged back into FreeBSD, allowing a peranent fork to occur.
Nah. Anyone can fork, any time, practically anything if you have the source code; sometimes it will be legal too. That's not interesting. What's interesting is whether the fork survives. Why would anyone else contribute to your branch when there's a main branch that *you've* left?
All I can say is that had better be one MOFA branch.
Actually, storing hydrogen for a house is no problem at all. It's just a pressurised metal container- there's no particular restrictions on how high the pressure needs to be or heavy the tank is or anything.
OTOH, a lightweight hydrogen fuel tank for a car- that's hard. If you want to move it around, then it's heavy (if you include the weight of the tank), or expensive (if you liquify it.)
But, if you just want a tank of hydrogen for your house- easy.
Last time I flew I switched off my phone and stuffed it into the overhead locker. When I reached my destination, it was: a) on b) nearly flat c) chock a block full of text messages welcoming me to all the airports we had stopped at. Presumably putting it into the locker had pushed the 'on' button. Great.
I was vaguely surprised that the battery was low- normally it lasts a week or more...
I don't know where you get "implies", but in fact you can't say, "Hey, I thought of a radar guided laser mosquito trap!" and patent it. An implementation is necessary.
Actually, incorrect you do not need a working example; except in certain special cases- IRC the patent office only accept perpetual motion machines patents if accompanied by a working model:-).
A patent is an *idea* that is being patented. It's your own problem if your idea doesn't actually work.
But there is a reason why there isn't an english translation for hentai.
It literally means 'pervert'.
I think you are trying to make out the Japanese to be more different than they really are- for example, the tentacle rape is just a side effect of their weird legal system (no human penises allowed, no sex between women and animals either, but sex with imaginary creatures apparently falls into a legal grey area... go figure!); and the apparent youth of the manga characters is illusory- the Japanese consider the characters to be older than Americans do- there are some cultural differences relating to reducing sun exposure in Japanese women and physical differences that tends to make them look younger to western eyes than they really are. You cannot really condemn Japanese Hentai manga unless you understand the environment that it has evolved in.
I mean, the Japanese may well consider LA porn to be barbaric and offensive (you can see pubic hair?)
Slashdot Mirror
"Why yes I am a rocket scientist."- Werner Von Braun
Dunno, but I find that chunks of 70+% bitter chocolate at regular intervals (every half hour or so) seems to keep me awake till the well after dawn when I play FPS's. Then again, I guess the FPS itself is stressful, so would tend to prolong wakefullness, but still, the chocolate seems to do something.
There's Caffeine, as well as other stimulants (theobromine IRC) in chocolate, so it's not too surprising I guess.
Yes, it's a sensible thing to do with a cash prize. It's probably not done with things like cars because the company offering the prize probably got it free from the manufacturer, and the prize givers can't easily pony up the extra money to cover the tax.
Sure, but the series converges, so if you pay 10% tax, the company could pay 1/9 of the value of the item to the tax man and they would be happy (0.10 + 0.01 + 0.001 + 0.0001 +... = 0.111111' = 1/9).
Yes, I expect it was fixed phase shift, which is correct for that- for a physically steered antenna. That says nothing about the general case of phased element array, which includes active elements with electronic phase shifting; the plasma reflector is an example of that. That's how you can arrange for electronic streering.
But neither of them are securing the wireless part of your network.
Correct! I wasn't protecting the wireless part of the network, as you more or less cannot (short of Tempest shielding). I was protecting corporate data. As a rule of thumb anyone can use the airwaves under FCC rules. I did make very sure that the wireless network didn't provide internet access, or any other services; so whilst outsiders ('Eve') could in theory have connected to the Wireless LAN from outside the building (difficult since the building was a weak approximation to a Faraday cage, but possible with an antenna of high enough gain), it wouldn't really do 'Eve' much good. The only exception was a direct attack on the clients themselves- I deployed personal firewalls for those; and the security turned out to be the same or better than when the same clients were connected to corporate LAN over the internet.
Ok, this is the last time:
You've several times explained how you can get range from triangulation, while calling it phase, but NOT from just knowing the phase of the signal.
The phase difference between the signal received at the middle of an antenna from either side of the antenna is slightly different from a nearby spherical source to that of a spherical source at infinity (plane wave). The wider the antenna is, the bigger the effect. You need a big antenna, but it can be flat and out the way- up against a wall for example. I simply can't be bothered to explain how you can do this- if you don't believe it can be done, or it's too complex.
Utter coddswallop. Neither the receive, nor transmit function works unless you have correct phase shift at each emitter. That's the whole point of a phased array. That's where the name "phased element array" comes from. If you have no phase shift then your antenna will work extremely poorly if at all.
No, it has become clear to me that you fundamentally don't understand phased arrays in general.
I've actually (in a past life so to speak) been tasked with helping secure a wireless network in an office environment. The solution was A: Encryption. B: Multiple AP's spread to give good coverage of the building's interior with any overlap well inside the perimiter. C: Very careful antenna selection to provide optimal coverage inside, with minimal sensitivity outside the building. D: MAC address filtering (which helps a little, but is still easy to bypass) E: Other stuff I'm not going to talk about here.
Yeah? So have I. The answer was: firewalls + corporate standard VPN. In your case I certainly hope your encryption wasn't WEP, but I don't particularly care; it sounds ghastly.
Later- much later.
Well, you're assuming that wired is secure- unless you're using Tempest shielding evesdropping is reasonably easy even with wired.
Basically security isn't all or nothing, ever.
In this case, forbidding/ignoring traffic from outside a configured physical perimeter would indeed result in more security for the network in many cases- it prevents people from injecting traffic to your network as well as improving throughput.
it should be marginally more efficient - and more accurate - to use separate arrays a fixed distance apart instead of running focusing calculations.
I think having multiple arrays scattered around the place is a very good idea anyway. The nice thing about this focusing trick is that they don't need to be phased together, since they independently can calculate distance. Having multiple arrays allows triangulation, and minimises the chances of the base station and clients lining up; which is likely to be the worst case.
Antenna's, in of themselves, don't have phase.
It's probably not normally considered like that, but different parts of any antenna are at a different phase; they have a formally linear response to a wave, right?
For a phased array, you can consider each 'active' element of a phased array to have a complex number that is multiplied by the signal that is measured at that point. The output of the array is the sum of these numbers. That forms a spatial filter. By calculating the complex number based on the speed of light delay you can (theoretically) focus the array onto a particular point in space by adjusting the phase/amplification in that way. The maths is trivial; in principle.
That's not correct. The analogy is not exact, but that's approximately the way GPS works.
It's just like focusing in the optical domain- you can focus a phased array a fixed distance away, rather than at infinity.
You seem to be thinking that the phased array can only focus at infinity, but that is not in fact the case, and focusing it at the appropriate distance gives more discrimination for the antenna.
Note that some of the theory behind synthetic aperture assumes focusing at infinity, but for a few elements at close proximity, it's not at all hard, or computationally intensive, to calculate the appropriate phasing.
Going back to the original topic, it's unclear whether this would be 'secure'- it's theoretically possible to arrange for the signals that arrive at the antenna to have the same phase as an antenna that is close to the array but from further away, but it's a whole heap of hassle and unlikely to be practical in most cases.
It's decidedly more exotic than the 18 element Yagi I've used for 2.4 gig work, or the 5 element phased array I've used fox hunting.
You still seem to be missing the point- this system is electronically steerable. Sure there are other ways to do that with switchable antennas, or physical steering, but this is another way.
This technique does not give a range. Only a direction.
It certainly can do; when the antenna subtends a large angle to the client; the point is that the phase at the elements of the antenna is not uniform across the antenna for the relatively small distances typically seen in WiFi.
My point is that your base station will have to consume X power for the RF section, and Y power for the processing section regardless of antenna type. A plasma antenna will add Z power to drive the plasma generator which strikes me as being considerably more power hungry than the X+Y power of existing base stations.
Yes, but with normal phased array, you need other switcheable electronics to introduce phase delays on the signal which you don't need here; they may well be expensive, and will consume power as well. I expect you are correct that the plasma solution is more power hungry, although I'd need to check. But in any case I'm quite unclear that power is a bottleneck for this application in most circumstances. I mean, a PC is taking 300 watts, and laptops are perhaps 60 watts; unless you are talking kilowatts, it probably goes in the 'who cares' category.
If you think about it, the wavefront from the trasnmitter has to hit the different parts of the antenna at the 'right' time- it's critically phase dependent- the wavelength of 2.5Ghz is about 15cm, so you can measure the distance to within a fraction of that.
Basically the bigger the antenna is, the further away you can distinguish the distance. In a fairly real sense you are doing triangulation/timing analysis independently from different sides of the antenna. It's exactly like focusing through a parabolic mirror in the optical domain.
Without detail I can't confirm it, but I suspect there's considerably more power going into ionizing the "antenna" than is going into radiating signal. That's just wasteful.
Not really. The radio power is limited by the FCC, but the base station power isn't. I mean, flourescents aren't particularly thirsty- and you only need a very small flourescent for this kind of thing.
First, we can get the same effect with a physical antenna array.
That's much more complex, notionally, it requires microwave frequency digital signal processing; the reflector system lets the antenna act as a spatial directional filter without any further processing.
It doesn't require an exotic plasma antenna (which still looks like a reflector to me from the pics, not a radiator) to tell which direction your users lay.
It's a reflective diffraction grating you can change on the fly. It de/reflects the signal back into a detector. It's not particularly exotic.
And you'll only realize a bandwidth advantage if the remote signals don't interfear with each other - which would requre them to also be highly directional, which brings us back to trying to get these things working on a portable device.
No, because the portable devices effectively have huge big directional virtual antennas pointed at them- so both send and receive are improved- only if the clients are very close together will there be problems.
Also remember you're limited by the processing power of the base station itself, and the inherent limitations of available bandwidth on any given freq.
The base station doesn't need much in the way of signal processing with this scheme- the filters can even be precalculated if necessary.
Well, I think it's a bit better than that- a base station with this technology can probably work out the distance as well as the angle- the antenna forms a spatially distributed antenna and hence can measure the phase and intensity and show where the user is.
there is the issue of power requirement - you need to create that plasma - fuel requirement - the gas you're ionizing
It's not a problem for a base station though- and that's where I see this technology going.
- and the shielding requirements.
There really aren't any- it's just like a flourescent bulb.
The main advantage of this system is that the highly directional antenna can actually permit two users to use the same bands without interference (since they are distinguished by their location, the base stations would be relatively deaf to any users not associated with them)- this greatly multiplies up the bandwidth of a WIFI network.
I know you're joking, but the BBC/ITV are both being really squeezed by the Murdoch Sky thing- if they can't use the weapons they have available to them, then in the long term questions like: "why do we need the BBC if nobody watches it anyway" could start to resonate a little too well.
I mean, ITV has always had more money than the BBC, but Sky has even more, and can just buy up the most popular shows/sporting events...
It shouldn't be, or atleast it may not be. The one good thing about patents is that you have to publish them, and using the same idea in a different area may well not infringe on the patent (depending on exactly how it is written)
Top secret military stuff just doesn't get published at all.
If you spin the disk more slowly, but have multiple heads then the limit probably doesn't apply- but the throughput would be the same.
And of course, you can always RAID your disks which does a similar thing. Or multiple platters, or...
Huh?
You have to ask? That was you behind me on the way home! Admit it!
It's not that ideas are public property- it's that the government wants to encourage the cross fertilisation you get when ideas aren't hidden in the middle of companies and corporations as 'trade secrets'.
So the government invents patents, which protect the idea for a few years (typically 15), but then expire, allowing the idea to be improved upon by others (independent of how bloody minded or wrong headed or just unable to capitalise on the idea that the patent holder may have been).
And as a side benefit, the idea is out there and can be perused, and the concept may be applied to a different area or business not covered by the patent.
So both sides gain- the government gains economic growth, the patent owner gains legal protection for 15 years. It also helps break up the monopolies that can form around some industrial processes- Governments hate competition (they think they should be the only monopoly :) )
So, patents are win-win. That's why they survive. It's nothing theoretically to do with the theory of "rights" or property- it just turns out that the nearest thing to handle this kind of 'ownership' is property law.
They aren't; they are going after some users of some P2P systems. P2P is a very wide area- with lots of protocols- most of the internet is P2P- the IP protocol itself is P2P. USENET especially is P2P.
Because its used mostly for piracy.
No; well maybe. But that's not necessarily true for all P2P or for all time. For example Skype is P2P, but there's presumably little or no piracy going on there.
Nah. Anyone can fork, any time, practically anything if you have the source code; sometimes it will be legal too. That's not interesting. What's interesting is whether the fork survives. Why would anyone else contribute to your branch when there's a main branch that *you've* left?
All I can say is that had better be one MOFA branch.
OTOH, a lightweight hydrogen fuel tank for a car- that's hard. If you want to move it around, then it's heavy (if you include the weight of the tank), or expensive (if you liquify it.)
But, if you just want a tank of hydrogen for your house- easy.
Last time I flew I switched off my phone and stuffed it into the overhead locker. When I reached my destination, it was: a) on b) nearly flat c) chock a block full of text messages welcoming me to all the airports we had stopped at. Presumably putting it into the locker had pushed the 'on' button. Great.
I was vaguely surprised that the battery was low- normally it lasts a week or more...
Actually, incorrect you do not need a working example; except in certain special cases- IRC the patent office only accept perpetual motion machines patents if accompanied by a working model :-).
A patent is an *idea* that is being patented. It's your own problem if your idea doesn't actually work.
Oh yeah, you knew what the *term* meant. You just couldn't understand my sentence; which is what we were talking about.
You just did. Congrats.
It literally means 'pervert'.
I think you are trying to make out the Japanese to be more different than they really are- for example, the tentacle rape is just a side effect of their weird legal system (no human penises allowed, no sex between women and animals either, but sex with imaginary creatures apparently falls into a legal grey area... go figure!); and the apparent youth of the manga characters is illusory- the Japanese consider the characters to be older than Americans do- there are some cultural differences relating to reducing sun exposure in Japanese women and physical differences that tends to make them look younger to western eyes than they really are. You cannot really condemn Japanese Hentai manga unless you understand the environment that it has evolved in.
I mean, the Japanese may well consider LA porn to be barbaric and offensive (you can see pubic hair?)