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Battery Breakthrough: Researchers Claim 70% Charge In 2 Minutes, 20-Year Life

mrvan Re:Just moves a choke point (395 comments)

Aire de Berchem is Luxembourg is (according to Dutch wikipedia) the busiest gas station in the world (mainly because Luxembourg has the cheapest gas in the region and it is on a number of busy roads). It pumps 850.000 liters per day, enough to fill up 17000 cars*. If every car needs 70% of 85KWh, this requirs 85k * .7 * 17k = 1GWh per day. If they can spread perfectly over the day, it means they need a 50MW power plant, which I guess is not too far out there. This will probably require some impressive capacitator / battery setup to get enough peak power though, no clue if something like that is feasible.

(the total amount of energy in 850k liters of gasoline is 42.4 MJ/kg * 0.77 kg/L * 850kL = 27 TJ = 7.5GWh. So it seems that the total efficiency of electric cars is about 8 times higher, assuming equal range, which is probably false. But a factor 5 might be around right...?)

*) the wiki mentions it's 80% diesel, and while diesel cars are pretty common here, I would assume that means that the majority of liters goes to trucks. Now suppose your Tesla truck with 500KWh needs to charge in 5 minutes....

about two weeks ago
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Four Dutch Uberpop Taxi Drivers Arrested, Fined

mrvan Re:News at 11. (282 comments)

This is nonsense. You can still buy paper single use cards, but now they have a little chip in them (and they cost a bit more).

I do think that the single use tram cards are way too expensive (2,70), but that's a different matter.

about two weeks ago
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Google's Security Guards Are Now Officially Google Employees

mrvan Re:Wow (134 comments)

Our cleaning is outsourced and the cleaners generally have little command of the local language. I know most of them by now, however, and have a little chat when I can. I leave my wallet and phone on my table if I go grab a coffee to allow them to clean my office (I work late a lot of times). Nothing untoward ever happened and I've not heard any of my colleagues complain.

about three weeks ago
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Microsoft Revives Its Hardware Conference

mrvan Re:Frosty pasta! (47 comments)

I really like the Metro UI as well, especially for desktops.

My wife is finally migrating to linux :-)

about a month ago
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Where Whistleblowers End Up Working

mrvan Re:Future wars (224 comments)

Existentialism is the enemy. Existentialism has always been the enemy.

about a month ago
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How Our Botched Understanding of "Science" Ruins Everything

mrvan Re:Proper Science is hard. (795 comments)

Scientist here - by geekoid's definition at least.

Scientists use jargon for the same reason sailors do - to efficiently communicate a very specific concept. In a sailing vessel at sea in a storm, you really don't want to take a minute to explain that you mean the green-white striped rope that connects the beam to the hull - you say mainsheet*.

Now, there is a lot of nonsense going on in science, with ridiculous performance metrics, a discouragement of actually innovative high-risk research, a sometimes religious worship of established names and theory; and a lot of stuff gets published not because it is particularly innovative, enlightening or even robust, but because it uses the right buzz words and cites the right people. However, that does not make science as an endeavour less wortyh - it's a bit like** how democracy is a good idea even if a lot of politicians (the ones in high places, at least) are dodgy.

* if my English sailing jargon is correct - not a native speaker
** my next analogy will be about cars, I promise

about a month ago
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Ireland To Host Robotic Sailing Championships

mrvan Re:A Little Perspective (14 comments)

This doesn't matter that much. Larger yachts sail more or less the same as smaller yachts; the main effect is that all forces are multiplied. For humans this makes a lot of difference: needing winches instead of pulling ropes by hand, being hit by the boom during a jibe changes from unpleasant to lethal, the ability to push off against the wall is greatly diminished, etc. For automatic sailing, however, the main effect will probably be cost rather than difficulty, as none of those factors are really important until material strenght becomes a problem. Smaller boats can even be more difficult to handle since the intertia is smaller compared to the wind forces (mass is cube of size, wind area square), making a smaller boat less stable.

about 2 months ago
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Algorithm Predicts US Supreme Court Decisions 70% of Time

mrvan Re:is it better than random? (177 comments)

That is correct, but not what the GP meant. If you can model the distribution (e.g. you 'know' that B is 90%) then you can weigh your random guessing such that it is correct in >50% of the cases, even without looking at the case itself (it is still 'random' in that sense)

Extreme case: I can predict whether someone has Ebola without even looking at them with >99.99% accuracy by just guessing "no" every time, since the prevalence of Ebola is >.001%.

Suppose the supreme court has 70% chance of overturning (e.g. because they choose to hear cases that have 'merit'), then an algorithm that guesses 'overturn' 100% will have a 70% accuracy. A random guess that follows the marginal of the target distribution (e.g. guess 70% overturn) also scores >50% (58% to be precise).

about 3 months ago
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Ask Slashdot: "Real" Computer Scientists vs. Modern Curriculum?

mrvan Re:wow great (637 comments)

Wow could you please not downvote me please thanks? That's really rude.

Why don't you impose a $500 fine?

about 3 months ago
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Dwarf Fortress Gets Biggest Update In Years

mrvan Re:Is it still braindeadly single-threaded? (138 comments)

It was meant neither as an excuse nor as an explanation.

Let's just say that apparently Toady has the kind of skills and character that enabled him to implement DF in the current fashion. And that is both a big compliment and a big gripe...

about 4 months ago
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Dwarf Fortress Gets Biggest Update In Years

mrvan Re: Is it still braindeadly single-threaded? (138 comments)

embarrassingly parallel has a specific meaning, namely that the task is composed of a (relatively large) number of sub tasks that can each be performed completely independent of each of the other sub tasks. So, any sane attempt to pathfind (say an A* search) is not embarrassingly parallel since whether a path can be pruned depends on the best paths found so far in other branches, and there is an optimal ordering for which branches to descend into first which is also dependent on what's happening in the other branches. I'm sure you can make a parallel version by e.g. forking out N possible branches to some depth, gathering state, and then pruning and ordering centrally and branching out again on the most promising branches, but this is not "embarrassingly" parallel.

about 4 months ago
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Dwarf Fortress Gets Biggest Update In Years

mrvan Re: Is it still braindeadly single-threaded? (138 comments)

For one unit, sure. The CPU problem in DF (as far as I understand) is that there are 200 dwarves, 100 goblins and 400 kittens all trying to pathfind at the same time. Unless I miss something, each of these units van pathfind in parallel since they don't "know" about the other's paths.

about 4 months ago
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Dwarf Fortress Gets Biggest Update In Years

mrvan Re:Is it still braindeadly single-threaded? (138 comments)

Yes... From what I gather, the developer ("Toady") is an autodidact that doesn't use any sort of version control and no multithreading. Although the simulation might be difficult to run in multiple threads, I think the path finding is one of the biggest CPU drains and that should be embarrassingly parallel. Also, he is really giving the community a tough time by having a monolithic game engine + GUI instead of some sort of modular system, which would allow the many programming-savvy fans to build tools much more easily (tools such as dfhack and therapist now use direct memory hacking, which is annoying (therapist needs root access, dfhack encapsulates df itself) but also unstable.

about 4 months ago
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Dwarf Fortress Gets Biggest Update In Years

mrvan Re:PeridexisErrant's DF Starter Pack - Get it! (138 comments)

Also, if you've never played DF, it is probably best to either wait a couple months until the worst bugs are fixed and the wiki etc are updated, or just grab the previous versions. This new version will still be quite rough at the edges and some of the info on the wiki, youtube etc will be outdated.

I'm pretty excited about the new release, I've been playing for a couple years and I hope that especially the AI behaviour has been improved although it is not listed in the change log as such...

about 4 months ago
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France Cries Foul At World Cup "Spy Drone"

mrvan Re:Luftfwaffe Light (138 comments)

I had to read it twice, but that's actually quite funny :-)

(no mod points today...)

about 4 months ago
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France Cries Foul At World Cup "Spy Drone"

mrvan Re:Other consequences (138 comments)

This is an important part of the story. Public decency laws, and nude beaches as an official exception to them, are not there to protect the nude people, they're there to protect the prude from the nude.

The sad truth is, however, that while being nude at a nude beach is OK, having a picture taken of you and distributed outside that context is not OK. For one thing, it violates my feeling of privacy more than a picture of me walking in the park (I guess there is still a remnant of prudishness there), but it can also damage my reputation and social standing among people who dislike nudity. Thus, it makes perfect sense to be stricter about taking and distributing pictures from nude beaches, just like there is a distinction between taking a picture of me in my front garden (maybe ok?), sunbathing in my back garden (less ok), watching television in my living room (bad) and having fun in the bedroom or bathroom (really bad).

(Note also that most people don't go to nude beaches because they're exhibitionist: they go there because it is much nicer to sunbathe and swim without swimming gear. If you've never swum naked, you should really try it one day, it's a world of difference)

about 4 months ago
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Ask Slashdot: Best Rapid Development Language To Learn Today?

mrvan Re:Im stickng wth C and shell scripting (466 comments)

For most* languages out there you can automatically create a binding to a C api, if 1:1 API use is what you want. It is true that C is the default goto language for libraries, but if you actually want to do something like parse plain text (or json/xml), communicate over a socket, use SCP, etc etc, it is by no means the easiest language to do something in.

For the record: perl was king more like 20 years ago. I started around 1998 and it was all perl. 5 years later I had switched to python and I think most people started realizing that perl was not the future. If you look at e.g. tiobe, you'll see that python went mainstream around 2004 and has stayed more or less constant since.

about 4 months ago

Submissions

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Python creator Guido van Rossum leaving Google for Dropbox

mrvan mrvan writes  |  about 2 years ago

mrvan writes "Guido van Rossum, the proclaimed python Benevolent Dictator For Life, is leaving Google in january to work for Dropbox. He is currently employed by Google, where he spends half his time developing the Python language. In their announcement, DropBox state that they relied heavily on python from the beginning, citing a mix of simplicity, flexibility, and elegance, and are excited to have GvR on the team. While this is without a doubt good news for DropBox, the big question is what this will mean for python (and for google)."
Link to Original Source
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E.U. Fines Microsoft (another) $1.3 Billion

mrvan mrvan writes  |  more than 6 years ago

mrvan (973822) writes "The New York Times writes: "European antitrust regulators on Wednesday fined Microsoft $1.3 billion for failing to comply with a 2004 judgment that the company had abused its market dominance. Microsoft had earlier been fined after the commission determined in 2004 that the company had abused the dominance of its Windows operating system to gain unfair market advantage. The commission imposed the new fine Wednesday, it said, because the company had not met the prescribed remedies after the earlier judgment. "Microsoft was the first company in 50 years of E.U. competition policy that the commission has had to fine for failure to comply with an antitrust decision," the European competition commissioner, Neelie Kroes, said in a statement."
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Electoral Compass for 2008 Presidential Elections

mrvan mrvan writes  |  more than 6 years ago

mrvan writes "The Electoral Compass was launched today by political scientists from the Free University Amsterdam in cooperation with the Wall Street Journal. On this voting aid website, you can fill in your position on a number of issues and compare it with that of the various candidates. Most importantly, at the end you can compare the differences per issue and see the debate transcripts or newspaper articles that contain the issue position of the candidate. An interesting point is that the researchers did not ask the candidates for their position, which carries a risk of getting optimized or manipulative answers. Instead, they coded the statements of the candidates found in the media and debates. More information about this compass and similar efforts for the last Dutch general elections can be found here."
Link to Original Source

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