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Comment: Achievement unlocked! (Score 5, Funny) 256

by Jeremi (#49819377) Attached to: Fuel Free Spacecrafts Using Graphene

Do you ever get the paranoid feeling that someone is occasionally modifying the laws of physics in order to advance the plot?

"Oh look, they're going to be stuck on Earth for an excruciatingly long time due to the exponential-propellent-scaling problem. Let's add a new capability to graphene that will give them a work-around for that."

I claim that two years ago the exact same graphene experiment would have shown no unexpected results; but now in 2015 we see this suspiciously useful behavior appear. I'm not sure how to test my hypothesis though :)

Comment: Re:Lemme ask you this ... (Score 4, Informative) 499

... under the dictatorship of Obama ...

Who is the one coming out asking the Congress to extend the Patriot Act?

Was it Cheney Rumsfeld Bush and Co., or was it Obama?

What kind of a dictator "asks" Congress for anything? A proper dictator would, you know, dictate his commands, and any Congressman who refused to rubber-stamp them would be fired, or shot (or both).

Comment: Re:Why is it worth that much? (Score 1) 143

by Jeremi (#49809945) Attached to: Mystery Woman Recycles $200,000 Apple I Computer

The only reason it's worth $200000 is because some idiot paid that much, because he's hoping that in a few years he can sell it to a bigger idiot for $250000.

Maybe that's his motivation; but it's just as likely he's trying to complete his collection of "vintage" computers and has money to burn. Not every collector is motivated solely by arbitrage.

Comment: Re:Answer (Score 2) 335

by Jeremi (#49788345) Attached to: How Much C++ Should You Know For an Entry-Level C++ Job?

I have yet to encounter a non-contrived example where multiple interitance is a plausible solution to a problem.

Okay, I'll give it a shot, then... here's where I find multiple inheritance not just plausible, but preferable.

I have a publish/subscribe model including an abstract-base-class/interface (call it IDataSubscriber) that can be subclassed by any object that wishes to be notified about e.g. data updates coming in from the network.

There are a number of common-case standard responses (implemented as concrete IDataSubscriber methods) to those data updates that are useful for many situations, and I don't want to have to have to rewrite them separately for every subclass, so I make a concrete or almost-concrete subclass (e.g. StandardDataSubscriber) that contains this common logic.

Finally, in my client code (based on Qt) I have a number of GUI widgets based on QWidget or QPushButton or whatever. I want these widgets to react to published data in the standard way, so I often end up with this:

class MyButton : public QPushButton, public StandardDataSubscriber {...}

... and it handles my needs nicely. It's also possible to do the same thing with "just" single inheritance and interfaces as well, or with Qt's signals-and-slots, but AFAICT do to it that way you end up having to do lots of manual method-call-forwarding through proxy objects (or, alternatively, lots of manual signal/slot connecting), which is less efficient, harder to read/understand, and more error-prone.

Comment: Re:30 years ago.... (Score 1) 293

by Jeremi (#49778387) Attached to: Amtrak Installing Cameras To Watch Train Engineers

So yeah, it's not as easy as just throwing a GPS on your locomotive and calling it good.

Still, even a partial solution (e.g. one that matches the train's GPS location, if known, against a table of specified maximum-safe-under-any-circumstances speed limits for that location) would prevent a train wreck in certain cases (such as the recent one that prompted this article). I'm all for full PTC, but I don't think the perfect needs to be made the enemy of the good here.

Comment: Re:Time to find better engineers (Score 2) 293

by Jeremi (#49778353) Attached to: Amtrak Installing Cameras To Watch Train Engineers

If the engineers' concentration is so fragile that they are going to be distracted by a camera, they are obviously not the right people to be operating complex machinery.

They suffer from a condition called "being human". It causes occasional failures in an otherwise operational controller-human, some very small percentage of the time. Even the highest-quality controller-humans have a non-zero failure rate.

Maybe we should just replace them with automation and run the trains remotely. They could keep one engineer per train to engage the manual override in the event that someone hacks the control infrastructure and tries to do Bad Things(tm) to the trains.

That is actually a pretty good idea, and it's more or less what PTC is intended to do, at least as far as the "avoid accidents" part of the job is concerned. Automating things further than that is also possible, although probably not really necessary.

Comment: Re:The one question (Score 1) 107

People looking at the car have to be able to tell that that car is an electric vehicle and not an ICE, in order to properly appreciate how the EV owner is saving the planet. By making it ugly, they can also allow the owner to sacrifice further by not driving a good looking car.

That's the cynical answer.

The actual reason that EV cars often look strange is because the designers are trying to make them as aerodynamic as possible in order to extend their range.

As battery power density becomes more adequate, maximizing aerodynamic efficiency will become less of a priority, so in the future you can expect designs that make efficiency tradeoffs in order to get a better look.

Neutrinos are into physicists.