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Programming

Regex Golf, xkcd, and Peter Norvig 172

mikejuk writes "A recent xkcd strip has started some deep academic thinking. When AI expert Peter Norvig gets involved you know the algorithms are going to fly. Code Golf is a reasonably well known sport of trying to write an algorithm in the shortest possible code. Regex Golf is similar, but in general the aim is to create a regular expression that accepts the strings in one list and rejects the strings in a second list. This started Peter Norvig, the well-known computer scientist and director of research at Google, thinking about the problem. Is it possible to write a program that would create a regular expression to solve the xkcd problem? The result is an NP hard problem that needs AI-like techniques to get an approximate answer. To find out more, read the complete description, including Python code, on Peter Norvig's blog. It ends with this challenge: 'I hope you found this interesting, and perhaps you can find ways to improve my algorithm, or more interesting lists to apply it to. I found it was fun to play with, and I hope this page gives you an idea of how to address problems like this.'"
Shark

Drone-Mounted Laser Weapons Are On the Way 116

Daniel_Stuckey writes "DARPA is funding research into drone-mounted laser weapons. The project, called Endurance, is referred to in DARPA's 2014 budget request as being tasked with the development of 'technology for pod-mounted lasers to protect a variety of airborne platforms from emerging and legacy EO/IR guided surface-to-air missiles.' The budget explains that it will be the first application of DARPA's much-discussed Excalibur laser defense system, which developed lasers powerful enough to use as weapons. With the new program, DARPA is focused on miniaturizing the technology, as well as 'developing high-precision target tracking, identification, and lightweight agile beam control to support target engagement. The program will also focus on the phenomenology of laser-target interactions and associated threat vulnerabilities." In other words, DARPA hopes that drone-mounted lasers will soon be able to shoot missiles out of the sky."

Comment Re:no grey goo? (Score 1) 274

The grey goo apocalypse has already happened. Bacteria are trying to do it for billions of years, and have had some nice accomplishments:

http://www.dinosaurapocalypse.org/the-big-oxygen-event.html

I really doubt we could do better than billions of years of evolution iterations.

Biological warfare, though, is another beast, since it targets human specifically.

Comment Re:Hold your head high ! (Score 1) 684

I think there is some truth in his "head games", but your argument is good too.

One thing that helped me get through bullying was martial arts; after a few months of practice, I wouldn't be able to outright beat the bullies, but I would at least be willing to put up a fight.

The boost in self-confidence that martial arts gave me made me a tougher target and they moved on.

But I was an easy target also because I didn't really belong there, with those people. I was naturally isolated.

It doesn't matter how tough you are, if you think differently, you will be a target.

Comment Feasibility of Strikes (Score 2) 761

Petroleum Engineer here, working with research.

I can tell for myself, engineers don't have much reason to strike. Why? Because it's usually pointless, there's no short-term damage to the employer. If an engineer doesn't show up, work simply goes on.

An engineer on the field has to strike for a few weeks/months to even begin to be noticed. In my case, working with research, I would have to strike for at least one year to do some real harm to my employer.

Engineers aren't useless; the most I know are well worth what they earn. But they influence mainly the future profits of the company, while blue-collar works have a direct influence on the daily profits, not to mention the quarter results.

Striking just isn't a nice strategy for white-collar workers. Threatening to go to a competitor is.

Now if people could threaten to move entire work groups to a competitor... that would be a negotiation I would like to see.

Comment Re:Not so fast (Score 1) 580

CO2 filtering is indeed tricky. Maybe ammonia fuel production would be more viable.

Ammonia as a fuel:
http://en.wikipedia.org/wiki/Ammonia#As_a_fuel

Production process:
http://en.wikipedia.org/wiki/Haber-Bosch

This process requires pure hydrogen, which could be made with high temperature electrolysis. I think this setup could work very well with solar thermal plants.

Other than the trouble that your fuel would really stink, it could be easier to produce than gasoline.

Ammonia is also extensively used for agriculture, so this process may be important even if fuel production doesn't take off.

Comment Re:Got to love public services... (Score 1) 91

Recirculation patterns are pretty common when the fluid flows through an expansion, specially if it's a sharp cut.

You can see it clearly in this case because of the gas bubbles, but this happens everywhere: next time you walk behind a building on the shore, watch the huge recirculation that the wind forms. This is usually how people with umbrellas end up wet "because of the crazy wind".

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