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  1. Re:Young'ns don't understand. on Are We Too Reliant On GPS? · · Score: 1

    Not really.

    GPS satellites orbit at 20,000 km and are therefore VERY hard to take out. We have bigger problems if that happens.

    Jammers that are strong enough to disrupt aircraft are strong enough to locate and destroy (AGM-88 HARM). Perhaps the trickiest situation would be small jammers in dense, civilian locations. In that case use them as a beacon a la Skyhook.

  2. Why not leave shuttle up there? on Shuttle Discovery Docks With Space Station · · Score: 5, Interesting

    The crew could take a Soyuz down.

    It seems like the shuttle would make meaningful addition to the usable to the ISS with its arm, cargo bay and pressurized quarters. What a shame to deorbit all that useful stuff and mothball it in a museum.

  3. Re:Physics on Neal Stephenson On Rockets and Innovation · · Score: 1

    Quicklaunch doesn't get nearly enough attention.

    The heavy, durable stuff should be shot out of a gas cannon and only the squishy humans should ride the rockets.

    http://www.newscientist.com/article/dn17931-blasted-into-space-from-a-giant-air-gun.html

    http://www.youtube.com/watch?v=1IXYsDdPvbo

  4. Re:Two problems with flying wings on NASA's Next-Generation Airplane Concepts · · Score: 1

    Third is that they are not naturally suited to being pressurized like cylinders. Flying wing cargo planes make tons of sense on the first two points, though I think most cargo is pressurized.

  5. Re:Insecure on First Ceiling Light Internet Systems Installed · · Score: 1

    You would need a very special camera to catch such high-speed toggling of the LED. Normal video 24-30 frames per second. That's well below the 300 baud of even early modems and you need at least twice the switching frequency to get the data (Nyquist). At 3MB/s they would need to be encoding a lot of bits per switch to get in range of a video camera. Some specialized sensors can do 1 million frames per second but their buffers can only handle 100 frames at a time.

  6. Biggest Human Error: 100% bets on Daily Double on IBM's Jeopardy Strategy · · Score: 2

    Most of the time players find the daily double while running through categories they know REALLY well. Then they only bet ~$2k out of their $12k stash.

    Even if they get the daily double right they will have to risk losing in final jeopardy b/c they haven't doubled the second place player's score. The smart play is to "make it a true daily double" and lap your opponents on a category you know well. Daily double questions are no harder than final jeopardy and I generally find them much easier. That's the time to risk it all. You not only increase your probability of winning but also your cash winnings.

    Imagine you are up 80% on your opponent and the final jeopardy category comes up as something you know NOTHING about. That's the time when you wish you bet more on that daily double.

  7. Re:Uh, how about butanol? on US Offers $30M For High-Risk Biofuel Research · · Score: 1

    Easy to drop that freezing point with additives and/or keep the fuel warm. Worst case you go dual fuel where you start up on gas then switch to butanol that has thawed out on the engine heat.

  8. Re:Magnetic gears? on Programmable Magnets · · Score: 1

    They won't have backlash but they will have a certain amount of compliance. High speed low torque situation would be perfect for magnetic gears but traction situations? not so much. I think dozens of people have had the idea of magnetic gears - I know I did. Isn't it a children's toy already?

    I hope this isn't worthy of a patent b/c anyone who has seen a Halbach array will immediately appreciate patterns of poles can generate interesting fields. Halbach arrays Manufacturing of the magnets is non-trivial and a bit more worthy of IP.

  9. Re:Don't try this at home kids on Building a Telegraph Using Only Stone Age Materials · · Score: 1

    Bronze is under appreciated. It is really hard but can be brittle. My recollection is that it is as hard as carbon steel, though no where near as ductile.

    You have to remember that iron back then wasn't steel, it was wrought iron or pig iron. A bronze ax is a totally decent tool and largely the equal of an iron one. I wouldn't want a long bladed bronze sword b/c it would snap easily but you could field a lot of shorter bronze swords for the effort of one iron one.

  10. Re:FEH on Genetically Engineered Silkworms Spin Spider Silk · · Score: 1

    Scuba tanks are not made of simple steel, they are an especially tough alloy that can handle the pressure cycles well. That factors into the cost.

  11. Re:Roku + media streaming on Google TV Details Revealed · · Score: 1

    WDTV in one of its various incarnations is $50 to $120 and it can play virtually any format from your media server and can stream video from the internet. The most recent, more expensive version can stream netflix. A media server can relay formats that are otherwise unsupported.

    If you want to integrate over the air TV get a SiliconDust HDHomeRun.

    If you want to integrate and DVR cable, get a Moxi or Tivo.

  12. Re:DD-WRT on Broadcom Releases Source Code For Drivers · · Score: 1

    This is huge. 2.4 kernels are so old that a lot of desirable software doesn't work properly. A modern kernel allows for much easier porting, IE optware.

  13. Re:WD HD Live is your friend. on Video Appliance For a Large Library On a Network? · · Score: 1

    I can't agree more. WDTV Live with b-rad's firmware is excellent. It can't really transcode other than transcoding to a particular output resolution but it is cheap and amazingly powerful. At ~$60-80 bucks it is worth a flier. Under the hood the WDTV Live is a 500mhz, 512meg linux computer. It's not fast at it but you can have the WDTV host an attached usb HD on NFS and SMB which isn't bad at 6 watts. The Sigma chipset is a decoding, transcoding beast. If the SDK for the 8655 ever gets into the wild it will be even better. The WDTV binaries are lousy and the after market firmware can only work around that so much. B-rad and the other coders have done an amazing job.

  14. Re:Yeah, but where does this get ME? on Abandon Earth Or Die, Warns Hawking · · Score: 2, Interesting

    Hawking is talking about self sustaining life without any support from the Earth. We are so far away from that it isn't even funny.

    If we could seed a self-sustaining human colony on Mars, we could probably maintain life on Earth. A nuclear powered habitat underground or underwater, "City of Ember" style, would be easier than Mars or the Moon if for no other reason than we don't have to lift any mass out of our 11.2 m/s, atmosphere leaden, gravity well.

    Some things we would need to figure out first:

    1. A vastly more efficient heavy launch system. Quicklaunch is immediately promising in that regard. The squishy humans can take a chemical rocket, but the heavy stuff gets shot out of a cannon. A space elevator implies emerging mastery of nanotechnology, which would also have a high risk of mass human extinction (bio-terrorism, gray-goo, deadly nanopolution). Solid rocket boosters will never get us there with enough of our luggage.

    2. A space station at L1. Shielding is tricky without the protection of the Earth's magnetic field but it is truly space, not like LEO. Hydroponics, asteroid capture for materials, solar and/or nuclear power, a linear motor launch system. It's feasible and asteroid capture could be immensely useful/profitable. Life support gases would be hard to maintain, even if capturing asteroids, but a heavy launch system would allow for a very large initial stock and multiple ultra-low loss gas barriers around the living quarters.

    3. A moon base. It would be largely underground to avoid gamma rays and meteorites. Same setup as L1 but mining the moon rather than asteroids. Gravity is a blessing and a curse. The moon doesn't have the mineral content of certain asteroids and the mass is stuck at the bottom of a gravity well. Supposedly there is water, which is fantastic and worth a base all by itself. With no atmosphere and a big mass to push against, the moon makes a great site for a huge linear accelerator. It might be easier to orbit valuable asteroids around the moon rather than slowing them to a stop at L1 anyhow.

    4. Finally Mars!!! By now we would have to have mastered building large structures in space. You'd need chip fabs in space, food and medical issues totally solved. A post-nuclear / nanotech apocalypse Earth should be looking rather hospitable around now...

  15. Re:Yeah, but where does this get ME? on Abandon Earth Or Die, Warns Hawking · · Score: 1

    In the past people thought a lot about the afterlife and how their terrestrial behavior would effect it. Even though lifespans were shorter, I think the concept of an afterlife made them think longer term than we do now. Can you imagine the pyramids being built in the present day?

  16. Re:Who cares? on China Shoots Down Another Satellite · · Score: 2, Insightful

    China needs us to buy the exports that their billion+ underclass help manufacture. That keeps those workers busy and distracted from the fact that they are being exploited by the privileged classes and deprived of any say in their government. Stop the exporting and it is a short road to civil unrest.

    China needs us to buy their products in US dollars so that the government can stand in between every export transaction and the local Yuan based economy and thereby control everything. They also get to wield that pile of dollars as a political tool in furtherance of their goals.

    A non-exporting China with a freely exchangeable currency? That's a nightmare for the CCP. They would lose some of their favorite tools!

  17. Re:Is this a closed system? on New Air Conditioner Process Cuts Energy Use 50-90% · · Score: 1

    It is a lot of water but you can reclaim the water that is driven off the desiccant if water is in short supply. The stock system doesn't do it but that hot, humid exhaust air can be cooled to ambient and much of the water will condense out. In fact this type of cooling system harvests water in humid environments.

    Evaporating water creates as much cooling BTU (negative btus) or coolth as the BTUs it would take to boil a like amount of water. It works out to about 6 liters per hour per ton of AC. A ton of AC is 12k BTU per hour and a BTU is ~ kilojoule.

  18. Re:Do we really WANT higher resoltuion displays? on HDTV Has Ruined the LCD Market · · Score: 2, Informative

    Yep, draw your GUI on a large resolution 200 DPI virtual screen AKA buffer and let a GPU scale it back down to the physical display's native resolution.

    Before Blu-Ray and HD-DVD there were not that many sources of HD content and people with HTPCs would upscale, filter and down res DVDs to try to clean up the picture. It wasn't 1080P blu-ray but it was better than the original, normally rendered picture to many people's eyes.

    It would still have scaling artifacts but it wouldn't / shouldn't look too bad. Alternatively use SVG for everything... that's the best solution.

  19. Re:Never leaves manhattan... on China To Connect Its High-Speed Rail To Europe · · Score: 1

    MTA subway ridership averages 7 million daily and there is currently only one subway that services the East side of uptown Manhattan, a huge commuter corridor and home to about 500k people. The new subway line would probably support 500k rides per day or more times 365 days a year times $2 a ride divided by a real interest rate of 4% is about $9B. Still too low, right? But MTA fares are subsidized 50% by car taxes and tolls. There's your $18B.

    Should it cost $18B? of course not but hey... this is New York. Nothing costs what it should.

  20. Re:Why not... on Recovering Data From Noise · · Score: 1

    I am not an expert on how GPS works but real world RF noise and encrypted frequency hopping military comms both look like noise. They are not sparse and no "filling in the blanks" will change that especially with the one buried in the other. Even the sequence of frequency hopping is intended to be pseudo random.

    The "key" for following the frequency hopping and picking out the signal is itself a pseudo random key. Then the comm itself commonly has encryption.

    This technique is about filling in data that is in some ways redundant and therefore compressible. The algorithm tries to figure out the lowest "entropy" uncompressed "plaintext" that would have sub samples consistent witht eh observed signal. Encrypted data and noise is devoid of redundancy and is incompressible by definition. No filtering or gap filling or anything is going to change that. It's not the black box from "Sneakers".

    My voice is my passport, verify.

  21. Re:Why not... on Recovering Data From Noise · · Score: 1

    This technique is not about detection but about "filling in the blanks" for signals that are highly ordered but for which you have limited samples.

    Encrypted military communications are not "sparse" as they have very high entropy. Said another way... it is too random for any "filling in the blanks" - so this technique doesn't work well for them - spread spectrum or otherwise. There is a big difference between reconstructing f(t)=t^2 + 4t + 7 from two samples (always perfect) and rand(t) which never works. Encrypted signals look as much like rand(t) as possible of course. In fact the set of signals you seem to think will be easily detected is in fact the precise sort that it cannot easily untangle. It would convert encrypted jibberish into mangled, encrypted jibberish.

  22. Re:Of Course on The Difficulty of Dismantling Constellation · · Score: 1

    QuickLaunch is one of the most interesting concepts for cheap LEO launches I have ever seen. It could make LEO incredibly cheap for hardened payloads (everything but people). Traditional chemical rockets or Virgin Galactic style two stage vehicles can transport the squishy and relatively light weight humans.

    http://www.popsci.com/category/tags/quicklaunch

    With one of these firing five times a day, it is really feasable to put a space tug in place for boosting orbits and repairing satellites, establish a fuel depot in LEO and even work on massive projects like a skyhook - the LEO hyper velocity kind that we actually have the cable to make.

  23. Looks like a Solid Oxide Fuel Cell on Fuel Cell Marvel "Bloom Box" Gaining Momentum · · Score: 2, Informative

    See the wiki entry here: http://en.wikipedia.org/wiki/SOFC

    The "inks" are probably catalysts that make the cell work better or at a lower temperature. My guess is that the inks help crack the hydrocarbon fuel.

    Solid oxide fuel cells are a bit like the low temperature hydrogen PEM cells. Two chemical reagents on opposite sides of a membrane really want to come together. That potential is harvested by a conductors. High temperature fuel cells, like SOFCs, can use hydrocarbon fuels because they can crack the carbon chain on the membrane surface and use the resulting hydrogen (and elemental carbon) to react with oxygen.

  24. Re:P4 and MythTV on Today's Best CPUs Compared... To a Pentium 4 · · Score: 1

    Me too. I love spending on new gadgets too and if electricity cost savings helps justify the purchase, so be it.

  25. Re:P4 and MythTV on Today's Best CPUs Compared... To a Pentium 4 · · Score: 4, Informative

    With 100 watts of power consumption at ~10 cents a kilowatt hour you would be spending about $88 a year to run your backend 24x7. That doesn't count the extra draw for air conditioning in summer months (the benefit in winter is pretty minor). Different costs per kwh or power consumption scale accordingly. Hopefully your P4 is a northwood and not a prescott! At some point the reduction in power costs will justify a switch to something like the Revo. My total power costs are about $0.30c a kwh (don't get me started!) so I could pay for the switch in a year.

    There is a great product called the "Kill-a-watt" that will measure the power consumption of a device simply by plugging it in through the kill-a-watt box. My Q6600 rig draws 120-140 watts for a good fraction of the day as measured by my kill-a-watt. It's a non-trivial cost and a 45nm chip might pay for itself in a year and a half.