We could add an additional layer of security to the SSN-ULTRA in the form of a time-based component. Say that we issue as a social security card a thin keyfob with a 20-digit LCD screen. The screen would have a number that changes every 12 hours in a sequence governed by the proper polynomial. That polynomial is your REAL social security number. So we have a bank of 9 shift registers, each containing a sequential-XOR chain 10 gates long. Basically, this keyfob generates and displays a different number every 12 hours based on a seed number which is kept secret. This displayed number is the one you use for gym memberships, credit cards, cell phones, and the like. All different, depending when you signed up. And each one is only good for 12 hours. In other words, if someone wants to check your police record with the government, they can do so for 12 hours, then the number that indicates you changes simultaneously in both your card and the government computer. If they want to check you again, they have to ask you for your number again.
A simple transaction with a government computer would verify that the 20-digit one links to you and whether you had any felonies. In other words, big important data. However, all of these different corporate scum wouldn't be able to sell data between themselves about your adult-toy buying habits based on SSN, because all of the numbers that describe you are different and unique.
Lastly, the interesting part is that you could see who queried your data and when, based on what numbers were given.
This concept is based on the RSA SecurID, a keyfob that does something very similar.
That's right, fear. Fear that this kind of thing might someday happen to THEM, and they're humiliated on national television for thinking the sun revolves around the earth, handing $5000 to a Nigerian email scammer, being sucked into an obvious pyramid scheme, saying global warming doesn't exist, and thinking evolution is a myth. We need a show that humiliates and pokes fun of every capable human that doesn't get basic logic, finance, economics, and science.
Frankly, I'm glad that rational humanism is finally winning out over caveman superstition and stupidity, and we the scientists aren't going to get another shot at stamping out stupidity and fundamentalism.
I want Judy and Joe Q. Lowest Common Denominator secretly thinking "I might be getting secretly recorded by hidden cameras for a nationally televised reality show" EVERY TIME THEY GO OUTSIDE. I want her to imagine the muffled laughter of a studio audience at her expense every time she can't figure out a 15% tip without a calculator. I want him to cringe at invisible cameras when he talks about Jewish plots to take over the world with his drinking buddies. I want her to mentally cower before a hyperkinetic Ashton Kutcher yelling "you got PUNK'D!" when she buys the latest Louis Vuitton bag made by Sri Lankan children for 1000x what the raw materials cost. We need to associate idiocy, ignorance, gullibility, and intolerance with public humiliation.
Make Joe and Judy fear public humiliation, and they'll eventually educate themselves instead of blindly going along to get along....ahhh, that feels better. Rant off. Some might argue that stupidity is an economic necessity - no one would ever make a profit on any consumer thingie if no one was susceptible to advertising and social pressure. Oh well.
This isn't the stock market or a commodities market, because in both of those you can resell what you've bought to another buyer. You can buy pork bellies or a share of XOM, wait until the price goes up, then resell it at a higher price (or cut your losses as the price descends). In fact, you CAN'T resell what you've bought barring some innovation in hyper-perceptive DRM that allows you to transfer ownership of the media file without violating copyright. Therefore, once you have bought the song, its value to you is at a flat zero. All this article represents is a pricing model of instantaneous movements up and down in price to follow the movements of the demand curve and maintain a revenue stream.
As such, I think it would work well from an economic standpoint. I can see the fun of watching prices bounce around on a screen.
Don't use these for servers. The 10KRPM SAS 2.5" drives are the only ones in the 2.5" form factor that don't crawl into a hole and die under enterprise loads. All of these drives are meant to function on a 30% or less duty cycle in a laptop. Sure, a nice inexpensive 2.5" SATA/ATA drive may be the best in terms of energy/IOP, energy/GB transferred, and $/IOP, but performance declines at.7% a week when running enterprise loads of short random seeks. This was the rule across all mfrs. and drives I tested, from 4200 RPM to 7200 RPM. Drives begin to die after three weeks - even with adequate cooling. All three drive designers and both system designers I talked to said that they're simply not meant to be run in a server.
Oh, and want killer IOPS with microsecond seek times? Try the Adtron SATA flash drive. 40GB will only set you back $18,000.:)
Agree that the grandparent is bunk. It's really hard to encroach all that much on someone else's spectrum without violating the power limits set by the UNII standards.
802.11b/g already has spread spectrum components - the coding varies by bitrate. 1Mbps is DSSS (direct sequence spread spectrum). In order to get the higher data rates, you need codes like BPSK, QPSK, 16-QAM, etc. in order to keep the processing rate low. I guess theoretically you could increase the DSSS chipping rate to 200x the bitrate instead of 20x like it is now, but that would come with increased processing requirements. The other codes I mentioned increase throughput without significant processing requirement increases.
What I would really like to see is a simulation of how scaleable UWB is for multiple hundreds of clients. UWB is DSSS without a carrier, so it's basically PCM. They use it for wireless USB, but I don't know how much it would scale.
Yes, because we all know that men are completely unsuited to take care of a child. In fact, we all know that they're unhelpful, loutish brutes who would only uptake information about the care of their own child if it's handed to them in a "fun parody of a famous American gangster epic". Excuse me, but GANGSTER EPICS teaching childcare? Of course. Men have such short attention spans that they coun't possibly understand childcare unless it was nicely packaged in some laddish way that appealed to their lower intelligence. Right?
Bullshit. Men have just as much of a childrearing instinct as women do - to suggest otherwise is sexist and wrong. We don't need this crap, it's belittling to our gender.
So, where's the manual that tells new mothers in a "fun parody" not to drown their children in large bodies of water? They certainly seem to need instruction on it of late.
In cell networks, each handset retains a low-level session to at a minimum two cell towers. When the signal from one tower gets too low, it pops over to the other.
Good things about this technology:
- I see this technology being used to reduce handoff delays between networks, or even between access points. The neat thing is that it does it on the client side, not the infrastructure side.
- The thing that this is going to be best at is mitigating the problems streaming video or audio across a network, where delays of 50ms can kill your stream.
- Solutions like MobileIP where each AP becomes aware of a care-of address that the client was previously associated with help handoff, but require new firmware on the access point or router. This puts that intelligence on the client side. Increasing the queue depths on both sides couldn't hurt, however.
- Because 90-95% of the handoff time between access points is a rescan for new channels, keeping a session going between two different networks and being aware of the channels around you will actually reduce congestion and handoff time because there is no rescan and its consequent flood of PROBE frames which clog the channel with BROADCAST responses!
- Because the clients will retain knowledge of who's around them, the access point's BROADCAST frames can come less often than the present ~100ms, increasing the available bandwidth.
Not-so-good things about this tech:
- Not a lot.
- Subnet resolution might be a problem, no, wait, it wouldn't because they maintain a separate IP address for each virtual adapter. However, if those IP addresses are on the same subnet and someone pings the broadcast address of the subnet, the clients on the other network might respond as well... but I guess that would only happen if the virtual adapters were bridged.
That's usually the problem with things like MobileIP - some routers don't get the message and update their routing tables so packets get duplicated all over the place.
- Available IP address space problems. If everyone is opening two sessions...
- Doesn't support WEP, but who cares. Everything important should be encrypted at the application level anyway. Thing that concerns me is the lack of 802.1x support.
All in all, not a bad idea. I hope to see more out of these guys. I'm taking this down to the lab to run tcpdump and airopeek on it.
Actually, on Mythbusters they tried to use people, and even with much practice they couldn't align the mirrors to a stationary target with much better than 5 degrees of accuracy. That's when Adam came up with the idea of using a frame to hold the mirrors.
However, in the Guinnes book of world records they had a photograph of a couple hundred of Greek sailors with polished mirrors of about 1sqm each setting a dinghy on fire from about 150m away.
Re:It's meant to counter supercavitation torpedoes
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Sonic Torpedo Defense
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· Score: 1
I can see someone attaching this to their car - that would be the first subwoofer I've seen that could physically flip the car over with a single bass hit.
BHWOMP!
It's meant to counter supercavitation torpedoes.
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Sonic Torpedo Defense
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· Score: 5, Interesting
I'm 90% sure I know what this is for. I'm not a naval warfare specialist, but I am a scientist with an interest in these things.
In the 1990s, the Russians developed the prototype for what would later be termed the Shkval or Squall supercavitation torpedo. Knowing the Russians, the Chinese probably have them too.
Cavitation is a phenomena where a body moving through the water pushes the water out of the way so fast that it creates bubbles around the object (fast = lower pressure = water vaporization = bubbles). You may have heard of propellers cavitating - that's where small bubbles of water vapor form then burst on the low pressure side of a prop blade, causing lots of noise and even damage to the blade when they implode.
Supercavitation, on the other hand, is an intentional phenomena where a blunt-nosed object is shot through the water, creating low pressure vortices on the sides. Air or exhaust gases are injected into these vortices, creating a static "bubble" around the object that drastically reduces friction - perhaps up to an order of magnitude. You have to fire these things at about 50mph or greater to start the supercav effect going, effectively "handing off" the bubble to the torpedo, which then sustains it.
The numbers on these torpedoes are incredible: we're talking about a 300mph torp carrying a 460lb warhead with a range in excess of 7000 yards. That's the tame version - others carry nukes. In other words, carrier-killers.
Supercavitation torpedoes, as you can imagine, are incredibly noisy and easy to detect - you just can't get away from them because they're so fast. This sonic projector essentially sends a high-energy single pulse through the water directed at an incoming torpedo. That pulse probably wouldn't be able to crack a torpedo - you'd probably need on the order of 250-500PSIG overpressure to do that, (scuba tanks contain 2000PSIG regularly). You wouldn't be able to detonate the high explosive, because you need a wavefront speed above the detonation velocity, which for C4 is about 7000m/s (much slower than the speed of sound in water, 1482m/s).
I don't have the time right now to spin the equations, so I could be wrong.
However, you would be able to disrupt and dissipate that bubble around an incoming supercavitation weapon with a high-energy sonic pulse. Break that bubble, and the torp stops dead in the water because it can't reform the bubble around itself. If it mistakes that sudden stop for a ship hull - boom.
Good on ya. I put all of my clients on net-15 business days for my invoices, and require a purchasing agent on the client side that I have unlimited access to within the equipment budget I specify and the client agrees to. Often, just emailing shopping carts gets the job done. I find I get more respect from the client when they're buying the servers and software I'm using.
DingDingDingDing! Mine too. I've delievered three projects ahead of schedule for a flat fee and got good references and repeat business from them. Do you negotiate milestone / date / performance bonuses as well?
Probably about $70K, depending where you live. However, if all of those five years are in the same specialty, you could probably be making 50% more as a self-employed consultant.
payscale.com is a good calculator, as is salaryexpert.com.
OK, so I hit the link to read the comments, closed my eyes before the page loaded, and said out loud, "Porn." I am glad that/. did not fail me.:)
Civilization as an educational narrative.
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Ask Sid Meier
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· Score: 1
Mr. Meier,
Civilization was the first computer game I bought with my own money. I credit much of my interest in ancient cultures, philosophy, government, and politics to your game. Despite the fact that the way such things are portrayed in the game is vastly simplified, the simple fact that they were portrayed at all as part of a larger narrative was sufficient to pique my interest in learning about them. Therefore, my question is:
What is your opinion on using Civilization-type games as a narrative to support an educational curriculum, and do you see a market for that kind of thing?
I have read several papers on this idea, and they seem to use Civilization as a substitute for the curriculum rather than as a supplement - and as a result, the students didn't seem to learn much. However, educators that use games as educational supplements are praised for how well their students understand and like the game. A standout educator in this area wrote a simple Javascript-based political and economic simulation of the Vietnam war.
An implementation of the game could span multiple educational levels. Consider a kindergarten teacher as the class starts out with a settler (on a custom map with no barbarians, of course). The class only runs the simulation once each week, so the kids have something to look forward to. The game serves as a narrative device to tie different elements of the childrens' education together.
"Oh, look! We, the whole class, we're in these wagons here. We're all tired of walking, so let's find a place to sit down. I'd like to be next to a river, how about you? I like mountains too. Have you ever been to the mountains? Here are some neat photos of mountains and animals. Let's draw some pictures of what we see!"
One can also extend this to the high school level - we already have things like the Mock UN, and the game could serve as a narrative there as well:
"Consider the following deployment of guerrillas, government troops, and refugees. Where should we recommend the refugees move to avoid the crossfire? How should we implement a medical and educational support system for the refugees? What are the budgetary requirements? What members of the UN should be involved?"
People of all ages seem to relate better to concepts if they're part of a story, and I'm interested in what you think of a game driving that story as part of a curriculum.
Answer - document custodian daemons.
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The Digital Dark Age
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· Score: 3, Interesting
Idea #1 What about a semi-intelligent expert system daemon that, given two document formats, could figure out how to convert one to the other?
Consider this: I would like to archive a set of CAD documents, but they're in archaic format X. Modern CAD formats are A, B, and C. CAD programs typically have ancestors that can convert from past versions for migration purposes.
So consider an interlinked set of CAD converters: #1 can convert formats F, G, H to formats D and E. #2 can convert formats W, Y, X, and Z to formats I, J, K, L, and F. #3 can convert formats D and E to formats A, B, and C.
Consider then a daemon that continuously monitors a filesystem looking for documents that aren't in a current format. It then fires up the converters and performs the conversion while archiving all past versions.
So in the example, the daemon fires up converters 2, then 1, and finally 3.
It could also cryptographically sign the files to provide a chain-of-custody.
It also maintains a set of applications and an emulator for different operating systems. When one needs to open an archaic dataset, one can either look at the converted files or call the daemon directly to seamlessly pass an emulated application session to the user if you want to look at it in the original form.
Idea #2 Documents could contain their own viewers. Yes, I know that's a bad idea making document objects executables, but hear me out. The document custodian daemon could also maintain a sandbox for document viewers to run in - it could even be a standardized virtual machine written in something like Java. This is getting a little out of my area of expertise, but I'll ask my girlfriend about it. It would get interesting after several levels of emulated virtual machines.
This year, hard drives became cheaper than tape for the first time in terms of $/GB. RAID with NFS should be way better than tape backup in terms of retention and nearline access, but I'm not really an IT guy.
I'm sure there's a business model in there somewhere.
Huh. Sharing? Under Mandriva 10.0, my Epson C64 was autodetected, installed, printed a test page, dropped into a Samba share, and configured there with about six clicks of the mouse and no driver disk. Installing the same printer under Win XP Home took 15 minutes and required the use of a driver disk.
I do that occasionally - come out with a massively wrong pedantic response, hoping to bring out the standards people and engineers who worked on the thing, just to see how bad the SNR is around here. Glad to see it's still not terrible. It's good to see people come out and defend stuff.
Please mod grandparent back down. Some people don't know how to read background to see that what I'm quoting is terribly wrong, and shouldn't be modded "Informative".
My 2001 project was on the usefulness of 2-MIMO to increase throughput at the fringes of wireless networks. Differential (MIMO vs. SISO) throughput turns out to follow a Rayleigh distribution as one gets out towards the fringes. I also modeled multipath, loss, and scattering in office environments. Measured signal granularity was significant, with nulls of -20dBm below average signal level on scales of half the wavelength at 2.4GHz. Average signal power over a given channel varied with a time constant of about 5000ms*dBm, both in the 2.4GHz and 5Ghz range.
MIMO-OFDM is going to work wonders on throughput and range with the True MIMO chipset, and I can't wait to get some of Airgo's stuff on the range here.
I'm writing a college textbook using the Linksys WRT54G and firmware for a networking lab (coming soon). And if you used the (large-networking-company) 340 series back in the day, I simulated and tweaked the antennas and tested the hell out of it in a massive site survey.
Don't worry, I'm a believer. Airgo's a cool company.:)
I design wireless networks and hardware for a living. I'm running simulations of video streams across ns2 and NCTUns as I write this.
Yes, you can increase throughput. Yes, you can cross-correlate FEC across channels to reduce errors. However, this solution hogs the spectrum, isn't tileable to create large wireless networks because of its inefficient use of channels (not to mention that the algorithm they're probably using only works because 802.11 has fairness problems, will definitely conflict with 802.11n (which also uses MIMO), and has a kook for a CEO.
"When MIMO was first unveiled, it reversed over 100 years of scientific thinking by harnessing natural radio wave distortions, which were previously perceived as interference, to deliver dramatically increased speed, range, and reliability," said Greg Raleigh, chief executive of Airgo. "With True MIMO Gen3 technology, our team has achieved a scientific milestone by proving that wireless can surpass wired speeds."
This guy is talking about something no more complex than using four radios at once and he's talking like it's the Second Coming. Could someone please bonk him with a hardbound copy of the 802.11n standard?
I like the idea of tying into multiple access points to increase throughput, but because their method relies on inherent 802.11 unfairness in order to work, I can't see this working in a large deployment.
This is pre-802.11n stuff, folks. Wait for the real stuff to come out from established vendors who actually contributed to the standard, instead of these guys who seem to be trying to break everything else by layering their solution on top of 802.11a/b/g, disrupting it in the process.
Is it just me, or does the description given by the inventors of the device's operation sound hilarious?
When walking, the body is like an inverted pendulum. After the foot is put down to take a step, the body vaults over it, causing the hip to move up and down about 1.6 to 2.7 inches (4 to 7 cm). The Suspended-load Backpack frame sits still on the wearer's back, and the load is mounted on a load plate that is suspended from the frame by springs. The springs allow the load to slide up and down on bushings constrained to vertical rods, thus allowing the load to move with the same vertical motion as the hip, but lagging it by a fraction of a second, producing differential movement between the frame and load. The pogo-stick-like movement of the load generates mechanical energy that drives a rack-and-pinion device that powers a geared DC motor that acts as a generator mounted on the frame.
Vault! Sproing! Slide! Pogo! Gears! Motors!
No thank you. I'd rather not walk around with a flapping, bouncing, sliding, grinding, humming backpack. This thing sounds like an invention of Wile E. Coyote.
Regarding these lightning guns and dazzlers, there's a good reason that nonlethal weapons exist, at least in the TSA's case. I've heard of a study done by the TSA that in a hijacking situation, it was judged to be quite traumatic for the passengers to see an air marshal rip out an attacker's throat, break his neck, or gouge out his eyes. Those are pretty much the exact words my friend quoted from the study.
Instead, it was judged to be easier on the passengers for the air marshal to point a blinking light at the guy and then bonk him nicely over the head while he's blinded.
Slashdot Mirror
We could add an additional layer of security to the SSN-ULTRA in the form of a time-based component. Say that we issue as a social security card a thin keyfob with a 20-digit LCD screen. The screen would have a number that changes every 12 hours in a sequence governed by the proper polynomial. That polynomial is your REAL social security number. So we have a bank of 9 shift registers, each containing a sequential-XOR chain 10 gates long. Basically, this keyfob generates and displays a different number every 12 hours based on a seed number which is kept secret. This displayed number is the one you use for gym memberships, credit cards, cell phones, and the like. All different, depending when you signed up. And each one is only good for 12 hours. In other words, if someone wants to check your police record with the government, they can do so for 12 hours, then the number that indicates you changes simultaneously in both your card and the government computer. If they want to check you again, they have to ask you for your number again.
A simple transaction with a government computer would verify that the 20-digit one links to you and whether you had any felonies. In other words, big important data. However, all of these different corporate scum wouldn't be able to sell data between themselves about your adult-toy buying habits based on SSN, because all of the numbers that describe you are different and unique.
Lastly, the interesting part is that you could see who queried your data and when, based on what numbers were given.
This concept is based on the RSA SecurID, a keyfob that does something very similar.
BWHAHAHAHA! (wipes away tears)
That's right, fear. Fear that this kind of thing might someday happen to THEM, and they're humiliated on national television for thinking the sun revolves around the earth, handing $5000 to a Nigerian email scammer, being sucked into an obvious pyramid scheme, saying global warming doesn't exist, and thinking evolution is a myth. We need a show that humiliates and pokes fun of every capable human that doesn't get basic logic, finance, economics, and science.
...ahhh, that feels better. Rant off. Some might argue that stupidity is an economic necessity - no one would ever make a profit on any consumer thingie if no one was susceptible to advertising and social pressure. Oh well.
Frankly, I'm glad that rational humanism is finally winning out over caveman superstition and stupidity, and we the scientists aren't going to get another shot at stamping out stupidity and fundamentalism.
I want Judy and Joe Q. Lowest Common Denominator secretly thinking "I might be getting secretly recorded by hidden cameras for a nationally televised reality show" EVERY TIME THEY GO OUTSIDE. I want her to imagine the muffled laughter of a studio audience at her expense every time she can't figure out a 15% tip without a calculator. I want him to cringe at invisible cameras when he talks about Jewish plots to take over the world with his drinking buddies. I want her to mentally cower before a hyperkinetic Ashton Kutcher yelling "you got PUNK'D!" when she buys the latest Louis Vuitton bag made by Sri Lankan children for 1000x what the raw materials cost. We need to associate idiocy, ignorance, gullibility, and intolerance with public humiliation.
Make Joe and Judy fear public humiliation, and they'll eventually educate themselves instead of blindly going along to get along.
This isn't the stock market or a commodities market, because in both of those you can resell what you've bought to another buyer. You can buy pork bellies or a share of XOM, wait until the price goes up, then resell it at a higher price (or cut your losses as the price descends). In fact, you CAN'T resell what you've bought barring some innovation in hyper-perceptive DRM that allows you to transfer ownership of the media file without violating copyright. Therefore, once you have bought the song, its value to you is at a flat zero. All this article represents is a pricing model of instantaneous movements up and down in price to follow the movements of the demand curve and maintain a revenue stream.
As such, I think it would work well from an economic standpoint. I can see the fun of watching prices bounce around on a screen.
I'm sorry, that research was for a client's new product. I can't tell you any more. :(
Don't use these for servers. The 10KRPM SAS 2.5" drives are the only ones in the 2.5" form factor that don't crawl into a hole and die under enterprise loads. All of these drives are meant to function on a 30% or less duty cycle in a laptop. Sure, a nice inexpensive 2.5" SATA/ATA drive may be the best in terms of energy/IOP, energy/GB transferred, and $/IOP, but performance declines at .7% a week when running enterprise loads of short random seeks. This was the rule across all mfrs. and drives I tested, from 4200 RPM to 7200 RPM. Drives begin to die after three weeks - even with adequate cooling. All three drive designers and both system designers I talked to said that they're simply not meant to be run in a server.
:)
Oh, and want killer IOPS with microsecond seek times? Try the Adtron SATA flash drive. 40GB will only set you back $18,000.
Agree that the grandparent is bunk. It's really hard to encroach all that much on someone else's spectrum without violating the power limits set by the UNII standards.
802.11b/g already has spread spectrum components - the coding varies by bitrate. 1Mbps is DSSS (direct sequence spread spectrum). In order to get the higher data rates, you need codes like BPSK, QPSK, 16-QAM, etc. in order to keep the processing rate low. I guess theoretically you could increase the DSSS chipping rate to 200x the bitrate instead of 20x like it is now, but that would come with increased processing requirements. The other codes I mentioned increase throughput without significant processing requirement increases.
What I would really like to see is a simulation of how scaleable UWB is for multiple hundreds of clients. UWB is DSSS without a carrier, so it's basically PCM. They use it for wireless USB, but I don't know how much it would scale.
Yes, because we all know that men are completely unsuited to take care of a child. In fact, we all know that they're unhelpful, loutish brutes who would only uptake information about the care of their own child if it's handed to them in a "fun parody of a famous American gangster epic". Excuse me, but GANGSTER EPICS teaching childcare? Of course. Men have such short attention spans that they coun't possibly understand childcare unless it was nicely packaged in some laddish way that appealed to their lower intelligence. Right?
Bullshit. Men have just as much of a childrearing instinct as women do - to suggest otherwise is sexist and wrong. We don't need this crap, it's belittling to our gender.
So, where's the manual that tells new mothers in a "fun parody" not to drown their children in large bodies of water? They certainly seem to need instruction on it of late.
In cell networks, each handset retains a low-level session to at a minimum two cell towers. When the signal from one tower gets too low, it pops over to the other.
Good things about this technology:
- I see this technology being used to reduce handoff delays between networks, or even between access points. The neat thing is that it does it on the client side, not the infrastructure side.
- The thing that this is going to be best at is mitigating the problems streaming video or audio across a network, where delays of 50ms can kill your stream.
- Solutions like MobileIP where each AP becomes aware of a care-of address that the client was previously associated with help handoff, but require new firmware on the access point or router. This puts that intelligence on the client side. Increasing the queue depths on both sides couldn't hurt, however.
- Because 90-95% of the handoff time between access points is a rescan for new channels, keeping a session going between two different networks and being aware of the channels around you will actually reduce congestion and handoff time because there is no rescan and its consequent flood of PROBE frames which clog the channel with BROADCAST responses!
- Because the clients will retain knowledge of who's around them, the access point's BROADCAST frames can come less often than the present ~100ms, increasing the available bandwidth.
Not-so-good things about this tech:
- Not a lot.
- Subnet resolution might be a problem, no, wait, it wouldn't because they maintain a separate IP address for each virtual adapter. However, if those IP addresses are on the same subnet and someone pings the broadcast address of the subnet, the clients on the other network might respond as well... but I guess that would only happen if the virtual adapters were bridged.
That's usually the problem with things like MobileIP - some routers don't get the message and update their routing tables so packets get duplicated all over the place.
- Available IP address space problems. If everyone is opening two sessions...
- Doesn't support WEP, but who cares. Everything important should be encrypted at the application level anyway. Thing that concerns me is the lack of 802.1x support.
All in all, not a bad idea. I hope to see more out of these guys. I'm taking this down to the lab to run tcpdump and airopeek on it.
Actually, on Mythbusters they tried to use people, and even with much practice they couldn't align the mirrors to a stationary target with much better than 5 degrees of accuracy. That's when Adam came up with the idea of using a frame to hold the mirrors.
However, in the Guinnes book of world records they had a photograph of a couple hundred of Greek sailors with polished mirrors of about 1sqm each setting a dinghy on fire from about 150m away.
I can see someone attaching this to their car - that would be the first subwoofer I've seen that could physically flip the car over with a single bass hit.
BHWOMP!
I'm 90% sure I know what this is for. I'm not a naval warfare specialist, but I am a scientist with an interest in these things.
In the 1990s, the Russians developed the prototype for what would later be termed the Shkval or Squall supercavitation torpedo. Knowing the Russians, the Chinese probably have them too.
Cavitation is a phenomena where a body moving through the water pushes the water out of the way so fast that it creates bubbles around the object (fast = lower pressure = water vaporization = bubbles). You may have heard of propellers cavitating - that's where small bubbles of water vapor form then burst on the low pressure side of a prop blade, causing lots of noise and even damage to the blade when they implode.
Supercavitation, on the other hand, is an intentional phenomena where a blunt-nosed object is shot through the water, creating low pressure vortices on the sides. Air or exhaust gases are injected into these vortices, creating a static "bubble" around the object that drastically reduces friction - perhaps up to an order of magnitude. You have to fire these things at about 50mph or greater to start the supercav effect going, effectively "handing off" the bubble to the torpedo, which then sustains it.
The numbers on these torpedoes are incredible: we're talking about a 300mph torp carrying a 460lb warhead with a range in excess of 7000 yards. That's the tame version - others carry nukes. In other words, carrier-killers.
Supercavitation torpedoes, as you can imagine, are incredibly noisy and easy to detect - you just can't get away from them because they're so fast. This sonic projector essentially sends a high-energy single pulse through the water directed at an incoming torpedo. That pulse probably wouldn't be able to crack a torpedo - you'd probably need on the order of 250-500PSIG overpressure to do that, (scuba tanks contain 2000PSIG regularly). You wouldn't be able to detonate the high explosive, because you need a wavefront speed above the detonation velocity, which for C4 is about 7000m/s (much slower than the speed of sound in water, 1482m/s).
I don't have the time right now to spin the equations, so I could be wrong.
However, you would be able to disrupt and dissipate that bubble around an incoming supercavitation weapon with a high-energy sonic pulse. Break that bubble, and the torp stops dead in the water because it can't reform the bubble around itself. If it mistakes that sudden stop for a ship hull - boom.
Good on ya. I put all of my clients on net-15 business days for my invoices, and require a purchasing agent on the client side that I have unlimited access to within the equipment budget I specify and the client agrees to. Often, just emailing shopping carts gets the job done. I find I get more respect from the client when they're buying the servers and software I'm using.
DingDingDingDing! Mine too. I've delievered three projects ahead of schedule for a flat fee and got good references and repeat business from them. Do you negotiate milestone / date / performance bonuses as well?
Probably about $70K, depending where you live. However, if all of those five years are in the same specialty, you could probably be making 50% more as a self-employed consultant.
payscale.com is a good calculator, as is salaryexpert.com.
Wrong. Prisoner's Dilemma. Look it up.
OK, so I hit the link to read the comments, closed my eyes before the page loaded, and said out loud, "Porn." I am glad that /. did not fail me. :)
Mr. Meier,
Civilization was the first computer game I bought with my own money. I credit much of my interest in ancient cultures, philosophy, government, and politics to your game. Despite the fact that the way such things are portrayed in the game is vastly simplified, the simple fact that they were portrayed at all as part of a larger narrative was sufficient to pique my interest in learning about them. Therefore, my question is:
What is your opinion on using Civilization-type games as a narrative to support an educational curriculum, and do you see a market for that kind of thing?
I have read several papers on this idea, and they seem to use Civilization as a substitute for the curriculum rather than as a supplement - and as a result, the students didn't seem to learn much. However, educators that use games as educational supplements are praised for how well their students understand and like the game. A standout educator in this area wrote a simple Javascript-based political and economic simulation of the Vietnam war.
An implementation of the game could span multiple educational levels. Consider a kindergarten teacher as the class starts out with a settler (on a custom map with no barbarians, of course). The class only runs the simulation once each week, so the kids have something to look forward to. The game serves as a narrative device to tie different elements of the childrens' education together.
"Oh, look! We, the whole class, we're in these wagons here. We're all tired of walking, so let's find a place to sit down. I'd like to be next to a river, how about you? I like mountains too. Have you ever been to the mountains? Here are some neat photos of mountains and animals. Let's draw some pictures of what we see!"
One can also extend this to the high school level - we already have things like the Mock UN, and the game could serve as a narrative there as well:
"Consider the following deployment of guerrillas, government troops, and refugees. Where should we recommend the refugees move to avoid the crossfire? How should we implement a medical and educational support system for the refugees? What are the budgetary requirements? What members of the UN should be involved?"
People of all ages seem to relate better to concepts if they're part of a story, and I'm interested in what you think of a game driving that story as part of a curriculum.
Idea #1
What about a semi-intelligent expert system daemon that, given two document formats, could figure out how to convert one to the other?
Consider this: I would like to archive a set of CAD documents, but they're in archaic format X. Modern CAD formats are A, B, and C. CAD programs typically have ancestors that can convert from past versions for migration purposes.
So consider an interlinked set of CAD converters:
#1 can convert formats F, G, H to formats D and E.
#2 can convert formats W, Y, X, and Z to formats I, J, K, L, and F.
#3 can convert formats D and E to formats A, B, and C.
Consider then a daemon that continuously monitors a filesystem looking for documents that aren't in a current format. It then fires up the converters and performs the conversion while archiving all past versions.
So in the example, the daemon fires up converters 2, then 1, and finally 3.
It could also cryptographically sign the files to provide a chain-of-custody.
It also maintains a set of applications and an emulator for different operating systems. When one needs to open an archaic dataset, one can either look at the converted files or call the daemon directly to seamlessly pass an emulated application session to the user if you want to look at it in the original form.
Idea #2
Documents could contain their own viewers. Yes, I know that's a bad idea making document objects executables, but hear me out. The document custodian daemon could also maintain a sandbox for document viewers to run in - it could even be a standardized virtual machine written in something like Java. This is getting a little out of my area of expertise, but I'll ask my girlfriend about it. It would get interesting after several levels of emulated virtual machines.
This year, hard drives became cheaper than tape for the first time in terms of $/GB. RAID with NFS should be way better than tape backup in terms of retention and nearline access, but I'm not really an IT guy.
I'm sure there's a business model in there somewhere.
Huh. Sharing? Under Mandriva 10.0, my Epson C64 was autodetected, installed, printed a test page, dropped into a Samba share, and configured there with about six clicks of the mouse and no driver disk. Installing the same printer under Win XP Home took 15 minutes and required the use of a driver disk.
Eh, fair enough. I was feeling cranky this morning.
Thanks for the response, much appreciated.
:)
I do that occasionally - come out with a massively wrong pedantic response, hoping to bring out the standards people and engineers who worked on the thing, just to see how bad the SNR is around here. Glad to see it's still not terrible. It's good to see people come out and defend stuff.
Please mod grandparent back down. Some people don't know how to read background to see that what I'm quoting is terribly wrong, and shouldn't be modded "Informative".
My 2001 project was on the usefulness of 2-MIMO to increase throughput at the fringes of wireless networks. Differential (MIMO vs. SISO) throughput turns out to follow a Rayleigh distribution as one gets out towards the fringes. I also modeled multipath, loss, and scattering in office environments. Measured signal granularity was significant, with nulls of -20dBm below average signal level on scales of half the wavelength at 2.4GHz. Average signal power over a given channel varied with a time constant of about 5000ms*dBm, both in the 2.4GHz and 5Ghz range.
MIMO-OFDM is going to work wonders on throughput and range with the True MIMO chipset, and I can't wait to get some of Airgo's stuff on the range here.
I'm writing a college textbook using the Linksys WRT54G and firmware for a networking lab (coming soon). And if you used the (large-networking-company) 340 series back in the day, I simulated and tweaked the antennas and tested the hell out of it in a massive site survey.
Don't worry, I'm a believer. Airgo's a cool company.
I design wireless networks and hardware for a living. I'm running simulations of video streams across ns2 and NCTUns as I write this.
Yes, you can increase throughput. Yes, you can cross-correlate FEC across channels to reduce errors. However, this solution hogs the spectrum, isn't tileable to create large wireless networks because of its inefficient use of channels (not to mention that the algorithm they're probably using only works because 802.11 has fairness problems, will definitely conflict with 802.11n (which also uses MIMO), and has a kook for a CEO.
"When MIMO was first unveiled, it reversed over 100 years of scientific thinking by harnessing natural radio wave distortions, which were previously perceived as interference, to deliver dramatically increased speed, range, and reliability," said Greg Raleigh, chief executive of Airgo. "With True MIMO Gen3 technology, our team has achieved a scientific milestone by proving that wireless can surpass wired speeds."
This guy is talking about something no more complex than using four radios at once and he's talking like it's the Second Coming. Could someone please bonk him with a hardbound copy of the 802.11n standard?
I like the idea of tying into multiple access points to increase throughput, but because their method relies on inherent 802.11 unfairness in order to work, I can't see this working in a large deployment.
This is pre-802.11n stuff, folks. Wait for the real stuff to come out from established vendors who actually contributed to the standard, instead of these guys who seem to be trying to break everything else by layering their solution on top of 802.11a/b/g, disrupting it in the process.
Is it just me, or does the description given by the inventors of the device's operation sound hilarious?
When walking, the body is like an inverted pendulum. After the foot is put down to take a step, the body vaults over it, causing the hip to move up and down about 1.6 to 2.7 inches (4 to 7 cm). The Suspended-load Backpack frame sits still on the wearer's back, and the load is mounted on a load plate that is suspended from the frame by springs. The springs allow the load to slide up and down on bushings constrained to vertical rods, thus allowing the load to move with the same vertical motion as the hip, but lagging it by a fraction of a second, producing differential movement between the frame and load. The pogo-stick-like movement of the load generates mechanical energy that drives a rack-and-pinion device that powers a geared DC motor that acts as a generator mounted on the frame.
Vault! Sproing! Slide! Pogo! Gears! Motors!
No thank you. I'd rather not walk around with a flapping, bouncing, sliding, grinding, humming backpack. This thing sounds like an invention of Wile E. Coyote.
Regarding these lightning guns and dazzlers, there's a good reason that nonlethal weapons exist, at least in the TSA's case. I've heard of a study done by the TSA that in a hijacking situation, it was judged to be quite traumatic for the passengers to see an air marshal rip out an attacker's throat, break his neck, or gouge out his eyes. Those are pretty much the exact words my friend quoted from the study.
Instead, it was judged to be easier on the passengers for the air marshal to point a blinking light at the guy and then bonk him nicely over the head while he's blinded.
This has the potential to be a big market.