Please create an account to participate in the Slashdot moderation system

 



Forgot your password?
typodupeerror

Comment Re:Great, bombs are now more accurate... (Score 1) 73

Hell there are even autonomous GPS guided haul trucks now that drive optimized paths to and from the autonomous shovels that also rely on GPS. Granted it is RTK that they use to get the accuracy necessary but that is just GPS with some base stations that provide corrections. If you can save 1% on fuel and keep those expensive shovels and truck not waiting you can save a lot of money and not waste resources.

Comment Re:Good for consumers? (Score 2) 73

That is probably more from the constant display update plus the transmit and receive from the data network. Now interestingly I use navit on my phone with the mapset of planet.bin (about 18 GB now) and even with the GPS off it will eat battery if I am moving around the map. Interestingly turning the GPS on or off doesn't appreciably change the battery usage when doing this. If I have had GPS on on the phone before starting navit it will have my location immediately but if not it will take a bit until it has a lock so that seems to imply that even having GPS means it is ready to go when something requests it. I have left GPS on on my phone with nothing actually polling it and while it does drain the battery noticeably faster, I will lose about 1/2 a day charge over about 3 days in this case, it isn't like it is massively eating through battery. Having a couple of very nice GPS modules that are a lot more sensitive and capable than what is available in a cellphone they only draw a max of 80mA@3V and that is only during the a cold boot acquisition and lock.

Comment Re:Good for consumers? (Score 1) 73

phones already use cell towers and wifi networks which are a lot more accurate and faster than GPS

No on the accuracy. Cell tower based location determination is accurate to about a city block and provided that you have WiFi with a known location you could get accuracy to about 2 buildings. The quicker to acquire seems like it may be reasonable but by having a better guess of your location you can get a lock quicker with GPS.

Comment Re:fire! (Score 1) 54

Are you sure about hydrogen being less leaky that helium? I thought it was the other way around - yes, helium is monatomic, but hydrogen is a lot smaller. The result being, as best I can gather, that an H2 molecule is slightly larger than a helium atom along its long dimension, but notable smaller along its short one.

Then again perhaps I'm thinking of hydrogen under pressure, where it will eventually pass through even solid steel tank walls. I've never heard of helium having such issues, but that could simply be because there are far fewer applications for high-pressure helium storage.

Comment Re:fire! (Score 1) 54

Hmm, on further though, we could fill the aerogel with hydrogen gas - that shouldn't alter the density much compared to being "vacuum filled", and would only a skin that prevented mixing, rather than preventing pressurized leaks. That would essentially eliminate the risks of leaks with even an extremely thin skin, while the aerogel would maintain a rigid airform and essentially eliminate the risk of fires. As of 2013 aerographene had been made with evacuated densities as low as 160g/m^3, compared to 1,225g/m^3 for air at STP, and 89g/m^3 for hydrogen, so you could get 976g/m^3 of lift at sea level. Not quite as good as helium, but you get the rigid airframe for free.

The real question would be how well could it survive pressure changes - a traditional airship has to reduce it's density as it climbs to avoid over-inflating and rupturing - aerogel ships would presumably have to do the same, but depending on gel porosity that could take a lot longer to get the air our (or back in again)

Comment Re:Cool! (Score 4, Interesting) 414

Actually, no, this is a very important result. We've been looking for gravity waves for years, and until now had been unable to detect them despite looking at sources that we should have been able to detect. This detection essentially closes an "uncertainty gap" in the theory - think of it like replacing "Here there be Dragons" on an old map with, "Nothing but open ocean here". It doesn't really change much, unless you happen to want to travel across the previously unknown area.

In addition, the article doesn't mention it, but by comparing the measured spatial distortions with he predicted values we open the door on the study of why the waves aren't as strong as predicted. Is there a flaw in the machine, or some hither-to unpredicted attenuation factor? The latter could potentially be every bit as earth-shattering as when the study of black-boy radiation revealed Quantum Mechanics.

It is in looking for confirmation of the predictions in current theory that both confirm that theory, and occasionally expose its flaws, which lays the groundwork for new theories. It may not be as exciting or glamorous as discovering something unexpected and new, but it's the same exact search that does both, and it's largely the luck of the draw as to whether the previously unexplored nook you chose to investigate reveals anything new. Its primarily through the exhaustive search of such nooks that we discover the unexpected phenomena that allows further theoretical growth. And in that pursuit "nothing unexpected here" is vitally important, as it allows future researchers to concentrate their attention elsewhere. Not to mention, it develops the early stages of the technologies that eventually allow us to harness the phenomena for productive uses.

Comment Re:Cool! (Score 5, Informative) 414

Well, except for the niggling one where it demands a completely different vacuum energy level than the similarly well-tested theories of Quantum Mechanics.

It's an odd situation - we have two well-tested and widely accepted theories, neither of which show any significant cracks, but which are utterly incompatible with each other.

Comment Re:Instance or class? (Score 1) 220

A whole lot of those would seem to fall under the "don't hit things" rules the AI is going to be operating under. You shouldn't have to use any special flagging system, just put out the proper safety cones to block off your work area.

Of course I've seen some really lousy traffic barrier placement too, to the point of following what was to all appearances the proper path, only to find myself clearly on the wrong side of the barriers. That might overtax the AIs "situational awareness", but hopefully it would only take a few accidents before road crews start making sure their barriers are placed unambiguously.

Comment Re:"you don't have to be very accurate" (Score 1) 255

Huh, it appears you may be correct. I didn't realize that the bulk of radioactive fallout material was actually vaporized material from the target that had been neutron-activated. Learn something new every day.

Of course you're still going to have neutron activated nitrogen, oxygen, etc. to deal with, but since they're at high altitude and won't fall out they should be diluted to safe levels before anyone on the ground is exposed, at least so long as we're only talking about a single explosion. There's probably also a lot less air within the neutron decay radius, and once the neutrons decay into hydrogen atoms they're relatively harmless.

Comment Re:Excess (Score 1) 281

Sam Kinison put it best:

You live in a fucking desert!! Nothing grows out of here! Nothing’s going to grow out of here!Come here, you see this? Huh? This is sand, yeah it‘s sand. You know what it’s going to be 100 years from now? It’s going to be sand! You live in a fucking desert!

Slashdot Top Deals

"The fundamental principle of science, the definition almost, is this: the sole test of the validity of any idea is experiment." -- Richard P. Feynman

Working...