Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 



Forgot your password?
typodupeerror

Comment Re: Looking more and more likely all the time... (Score 1) 502 502

What I don't understand, is why they even bother with microwaves at all. Just fill up the container with gas molecules and keep them warm. More molecules will bounce against the wide end than against the narrow end, so the device will produce thrust! Right?

(Obviously I know that's wrong, but why exactly would the EM drive produce thrust while my enclosed gas molecules won't?)

Comment Re:It's a Limited Threat Model Definition, not DRM (Score 1) 198 198

their threat model was to let cooperating people have some guarantee that their email would go away when they wanted it to, not to keep uncooperative people from doing that because you just can't stop screenshots / cameras / sender saving a copy /

(...)

If you wanted to do a "no forwarding" version, you'd do it by setting rules on who could access it, whether by IP address or some ID in the reader plugin or delete-after-one-read or whatever.

The problem with no-forwarding is that people who want to forward the message anyway, by definition turn into non-cooperating people. You might as well just add a text "please don't forward".

Comment Re:I see theyre using the Step 2 profit model (Score 1) 188 188

Well, if people are complaining about electricity being dirty because in many places it's still produced using coal, and you say that extracting petroleum is so much easier than extracting coal, a logical conclusion would be that we should ditch coal and just burn petroleum to make electricity. OK, you didn't actual "say" that, but it would be a logical conclusion. And if it was a wrong conclusion (which I think it is), there must be something wrong with one of the premises.

Anyway, we've got plenty of clean energy in Europe and getting more and more, so at least over here in the developed world the choice for electric cars should be clear.

Comment Re:I see theyre using the Step 2 profit model (Score 1) 188 188

FWIW, extracting petroleum is much easier per BTU than extracting coal, so I actually am more skeptical of the conclusions of the reporter you reference.

Are you saying they should use gasoline rather than coal to produce electricity?

Comment Re:I see theyre using the Step 2 profit model (Score 3, Interesting) 188 188

Yes, just a few weeks ago an article was posted here on Slashdot saying that the amount of electricity needed to pump up, refine and transport gasoline is about the same as that consumed by an electric vehicle for the same distance. So when you have finished filling up your gas tank, you have already used the same amount of electricity as the electric car and you haven't even started burning the fuel yet. Did this "study" take that into account?

Add to that the fact that pollution for electricity generation normally happens outside population centers. You should see the smog produced by cars in front of my kids' school on a foggy morning. I can't wait for all cars to be electric.

Comment Re:With stock tires on my local road? (Score 1) 171 171

Nothing to do with traction or downforce. The old insane mode was limited by amps above 30 mph, so acceleration started tapering off. The new ludicrous mode can pull more amps so, while acceleration is the same up to 30 mph, it will keep that high acceleration up a bit longer. That doesn't require any extra traction.

Comment Re:Crash Mitigation (Score 1) 549 549

And releasing the brakes before impact may well be a bad idea. It reduces damage to the car, but actually increases the impact on the occupants. And makes you more likely to hit someone in front, as well. Keeping max brakes lets the car move as little as possible, which is best for the occupants even though it may mean more damage to the rear of the car.

So there, a pefect example where your instinct human reaction may actually turn out to be worse than what some engineers with plenty of time can come up with.

Comment Re:Crash Mitigation (Score 1) 549 549

I do get that impression from some of the crash descriptions. The cars are extremely cautious and will often brake in situations where normal drivers wouldn't. There was one, for example, where a Google car was rear-ended while very slowly passing an accident site with emergency vehicles on the emergency lane (they were not on the road itself). Many drivers wouldn't even slow down, or only slow down a little bit, while the Google car did slow to a crawl. Other drivers simply don't expect this, they are passing the site at normal speed, probably getting a peek of the accident, and all of a sudden there's this "idiot" (in their eyes) Google car in the way. There was also one where a Google car was crossing an intersection, with right of way, a car from the other street rolled through a stop sign, the Google car braked because it judged that there would be a "near" collision, and the other car hit the rear end of the Google car. Quite possibly, the other car's driver had judged that he could pass behind the Google car and did not expect it to suddenly brake. The near collision turned into a real one.

There were several examples like that. And yes, I know what a lot of people will say, driving slowly is safer, you should always slow down when there's an emergency vehicly anywhere in sight, you should never roll through a stop sign, etc... Fact is, though, that most human drivers have certain expectations about other drivers, and the Google car often behaves differently. Sudden braking "just in case" is not always a good idea. You may say afterwards "yes, the human reacted too late, he wasn't paying attention, not keeping enough distance, going too fast, etc...". But if it does indeed turn out that Google cars are in more accidents (even though they are never at fault), that may mean that some adjustments in its logic are in order. Simply to accomodate the mistakes and bad behaviour of humans.

I have yet to see any problem, however complicated, which, when you looked at it in the right way, did not become still more complicated. -- Poul Anderson

Working...