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  1. Re:A me too case? on Japan's L-Zero Maglev Train Reaches 310 mph In Trials · · Score: 1

    That might be part of the reason but it is certainly not the whole reason.

    Case in point: trains in the Netherlands are pretty comfortable, even if most train rides are less than an hour, and two hours in a train is a long ride.

    Trains can afford to be more comfortable because the extra operating costs of comfort are a lot less, since the whole thing doesn't need to be airborne. Surprisingly, the capacity and mass of a modern train (e.g. http://nl.wikipedia.org/wiki/Dubbeldeks_interregiomaterieel) and a boeing 747 are about equal. The train is 350 metric tons for about 570 passengers; the boeing is 347 metric tons for 524 passengers. However, for the boeing fully half of that is fuel. Moreover, the train is more than twice as long as the airplane and has two decks over the whole length. A lot of comfort (leg room, room to walk around) doesn't cost mass or money, but makes the vehicle longer. Since trains rest on the ground and are guided by rail, while airplanes need to stay intact by their own integrity under gravity, trains can be quite a bit longer than planes.

    There used to be 'third class' carriages as well aimed at the labouring class, but these went out of fashion. Apparently, people are willing to pay a bit to get a more comfortable ride. Theoretically, there is an equilibrium comfort where the marginal gains and costs of adding extra comfort are in balance; the point at which this is reached depends both on the willingness to pay for comfort and on the cost of adding comfort, so it stands to reason that trains are more comfortable.

    (of course, as pointed out above, we don't really know since in most countries (even the US!) passenger rail is handled by a monopoly company, so we can't choose between Ryan Air and Emirates. Europe is starting to see a bit of competition on the tracks, but it is technically very difficult to allow multiple trains on the same route on the same infrastructure. So, it could be that we are paying too much to get too much comfort, and would rather have a cheaper service where they cram more chairs in each carriage...

    (that said, most of the 'frills' that all the airlines used to have (free meals, free drinks, a waiter coming to your chair to get orders) aren't available in most commuter rail lines that I know of, so the whole thing is mainly about leg room and chair comfort)

  2. Re:The real issue: U.S. government corruption. on The Legal Purgatory at the US Border: Detained, Searched, and Interrogated · · Score: 1

    So the bigger question is: why doesn't truecrypt have an option for multiple hidden partitions, so you can have your "encrypted" partition with your personal correspondence, then a "hidden partition" with something legal but more sensitive (e.g. soft erotic pictures), a "superhidden partition" with something questionable (movies 'in action' with your mistress), and a "megahidden partition" with the stuff you actually care about. How can they know how many partitions you have?

    What would be better, however, is to have an encrypted filesystem based in "data files", e.g. excel sheets or csv files with plausible column names (case no, var0001 ... var0090) and random seeming numbers, so you can claim that they are measurements or analysis files or whatever. Since the file (or files) is contained in your regular file system, no need to explain missing hdd space and no fear that you accidentally overwrite the sensitive data as you risk (iirc) when using truecrypt with the hidden partition hidden.

  3. Re:How accurate is the sea level rise figure? on Huge Canyon Discovered Under Greenland Ice · · Score: 4, Informative

    The sea level rises because the stuff covering Greenland is ice. When it melts it flows into the ocean, raising sea levels. Greenland is around 2M km2, and the ice sheet is around 2km thick, so we're talking about 4 million cubic kilometers of water. Earth has around 361 sq kilometers of water, so spreading the water around the earth gives around 10 meters of ice on each meter of water, or around 9 meters of water. In other words, (1) greenland is huge, and (2) the sea level rise is purely ice flowing into sea and has nothing to do with geological changes.

    Greenland rebounding does absolutely nothing because the "extra" volume is not taken out of the ocean. The water doesn't suddenly jump back up on the land.

    (arctic ice melting does not affect sea levels because the weight of the ice is already displacing water. Antarctic ice and glaciers on land are in the same situation as greenland ice)

  4. Re:Useless academic is useless. on Scottish Academic: Mining the Moon For Helium 3 Is Evil · · Score: 1

    Harvesting the energy is not necessary the problem: the problem is transmitting it to the Earth surface.

    Perhaps do it as we do currently - do the stuff that needs a lot of energy near the energy source. Blast furnaces are built near coal (athough there are chemical as well as energy reasons to use the coal), aluminium smelters near hydro power and so on.
    Transmit it to the Earth's surface or wherever it is needed as manufactured items. That's still not trivial since it requires a huge change in velocity to land stuff undamaged, and atmospheric friction isn't going to be enough on it's own, but we've got more of an idea of how to do that than transmitting terawatts of electromagnetic radiation around.

    So you think that bringing aluminum ore into orbit and then dropping the smelted aluminum down is a good idea?

    From good old wikipedia: "The most modern smelters achieve approximately 12.8 kWh/kg". This is the maximum gain.

    However, you first need to send up aluminum oxide (Al2O3). Chemistry is a while ago but I think that means that the aluminum:oxide weight ratio is 2*29 : 3*16 = 1.2. So, for every kg of Al you need to send up 1.8kg of aluminum oxide.

    Assuming that this happens in geosynchronous orbit, the aluminum oxide needs to gain around 60 MJ per kg, so around 100MJ for every kg of Al. 100 MJ is around 28 KWh, so more than twice the cost of smelting it on earth, and this is assuming that we don't need any energy for sending up the rocket, fuel etc, ie we can fling it into orbit using a catapult. Low earth orbit is a bit cheaper (ardound 33%) but not so much that this becomes feasible.

    So, even ignoring the problem of getting the stuff down (which doesn't need to cost any energy I suppose), the suggestion doesn't make any sense unless you can harvest the orbital energy again from the falling aluminum...

    (The only way in which it could make sense is if the aluminum was used in space to build spaceships, and the "waste" oxygen was used for breathing, but even then I'm not convinced that mining the stuff on earth is a wise choice in the first place...)

  5. Re:To answer GvR's question on Interviews: Guido van Rossum Answers Your Questions · · Score: 2

    And in theory you can write all the compute-expensive routines in C++.

    Sure, but then that's not Python being fast, it's C++ being fast. "You could write the expensive parts in C or C++" can be said of nearly any language. :-)

    Not quite. In java and most other languages I know, you would have to make quite some changes to the rest of the code to get it to communicate with something written in C.

    In CPython, you can replace a module and the rest of the code won't notice, e.g. in

    import mymodule
     
    x = mymodule.compute_answer()

    mymodule can be a python module or a c module and you really don't need to know or care. You can build the prototype in python and later replace it with a C module, and unittest and benchmark both. You can even do it conditionally, e.g. replace mymodule by something like

    try:
      from mycmodule import compute_answer
    except ImportError:
      from myfallbackmodule import compute_answer

    And the same original code would use the c module if available, and otherwise the fallback module.

    Even if you don't do any of this, you do get benefits, since the expensive parts of the standard library and 'computational libraries' like numpy are written in C. If you can write your problem with efficient use of these functions, especially turning loops into vector/matrix calculations that are done by numpy, you can get the speedup without writing a single line of C. I've actually sometimes encountered a slowdown after reimplementing in C because all the expensive bits were in library calls that were apparently better written than my rewrite.

    Finally, there are tools like cython which allow you to add type hints to your python code that compile to C code. This will be slower than hand written C code, but require a lot less changes to the module and is less error prone, and in my experience can easily give a 10x speedup with a couple of "int" hints, especially in nested loops.

  6. Re:Broaden your functional horizons, Guido! on Interviews: Guido van Rossum Answers Your Questions · · Score: 1

    +1, I'm a big python fan, but I think the whitespace is a mistake, for a number of reasons:

    1) a snippet of whitespace-blocked code has an absolute indentation level; while a piece of curly bracket style code has relative levels. This makes copy paste and refactoring clumsy. A 'python aware editor' does not really solve this since there is not 'end of block' mark except for the indentation

    2) the python whitespace system is redundant in itself by requiring both a colon and a increase-indent token as a block starter. Why is the colon required if the increase-indent makes it obvious that a block is starting (and all the block statements, ie if for def class etc, require the colon anyway, there is 0 information in the colon)? In fact, since the end of a 'block statement' always starts a new block

    3) why replace a somewhat redundant system that works relatively well and is used by the majority of languages by a new redundant system that is not really tested? I am sure they didn't really anticipate the snippet copy/paste or refactor difficulty - in the motivations they talk about easy to learn for beginners, but I don't think you should sacrifice usefulness of the language for a slightly gentler learning curve. Also, with curly brackets existing editors/ide's would be more or less useful, with basic highlighting, folding, structure-display, etc still working; while this requires completely new modes/editors to be developed

    4) it doesn't really solve a problem, since any ide or (almost) trivial preprocessor can 'correct' the indentation based on curly brackets

    5) it is keeping some people from using the language, which is a shame, because they might contribute to the language or community; and it is distracting the discussion away from a true discussion of the merits/drawbacks of the language, e.g. static vs dynamic typing, but also having classes and functions be true first level citizens without the need for clumsy introspection, yet not choosing the obvious next step of making class and def functions instead of statements.

    (PS I have no problems whatsoever with newlines ending statements. You can still use semicolons to put multiple statements on a line (generally a bad idea even in C) and since open parentheses suppress statement ends it almost never leads to problems. I think a '\n' is a more intuitive statement ender that a ';'. )

  7. Re:Gawd on Love and Hate For Java 8 · · Score: 1

    Java -> python programmer, both around 5-10 years (partially overlapping and with some R thrown in)

    Although the skill and character of the programmer is absolutely the primary thing, I do think that language makes a difference, moreso than tools. If I'd have to rank, I would rank programmer > API/libraries > language > tools. I used to write java in Eclipse and could not live without autocomplete, templates etc. I write python in vanilla emacs and don't miss it at all. Without need for both memory management and "type management", you need a lot less cruft in python so less names, classes etc to remember, and certainly no WidgetConstructorFactoryInterface3. Also, having to reference the real documentation frequently is also a boon, as good documentation (e.g. python stdlib, django) contains very important information that might be missed by relying on autocomplete and assuming you know what something means.

    If someone would write a good autocomplete for a dynamic language with metaclasses and other magic I would be game, but I fear that that is either theoretically impossible to do completely & correctly, or somehow requires running the whole program dynamically while typing, which just sounds painful. I tried PyCharm a while ago but it was clunky and incomplete. But in any case, I choose python+plain editor over java+eclipse for any project unless I know that java has an excellent library for something I need, which rarely happens.

    (and just to defuse the compiler catches errors argument: unit tests + code checkers > compiler errors, especially given the horrible workarounds that are sometimes needed in Java to satisfy the typing system that enables the compiler to catch errors)

  8. Re:Which has multiple benefits on Electric Vehicles Might Not Benefit the Environment After All · · Score: 1

    It's also way more efficient.

    See, that's what I thought as well, but it turns out it is simply not true.

    Power stations have a heat efficiency of around 40-45%, electric engines are around 90% efficient. Modern gas engine are 35-40% efficient. So, in total the direct efficiencies are quite comparable.

    http://www.eia.gov/tools/faqs/faq.cfm?id=107&t=3
    https://en.wikipedia.org/wiki/Engine_efficiency
    http://in.answers.yahoo.com/question/index?qid=20100628191919AAh0mSc

  9. Re:Depends on the energy source duh! on Electric Vehicles Might Not Benefit the Environment After All · · Score: 1

    Right. There are two pertinent questions.

    (1) How much total pollution does driving a set distance generate, and how easy is it to reduce this pollution?

    For gas cars, the pollution comes from burning gas, and it can be reduced by increasing ICE efficiency and by burning renewable sources like ethanol or hydrogen. Both are quite limited since ICE efficiency is limited by heat engine physics and has been optimized quite effectively already for around 100 years, and alternative sources require non-renewable energy and/or a limited resource like agricultural land to produce.

    For electric cars, the pollution comes from producing the electricity. In most countries, this is 90% or more from burning fossil fuels. It is often said that this is much more efficient that ICE's, but he difference is quite marginal: modern cars operate at up to 35% or even 40% (diesel) while power stations operate in the low 40% efficiency and the electric engine is around 90% efficient (https://en.wikipedia.org/wiki/Engine_efficiency, http://www.eia.gov/tools/faqs/faq.cfm?id=107&t=3 and http://in.answers.yahoo.com/question/index?qid=20100628191919AAh0mSc), although gas cars have further losses in gear and transmission systems that electric engines can avoid. However, shifting to less pollution source power is easier as there are almost limitless energy sources (solar, water, wind, waves etc) that do not produce direct pollution and do not compete for e.g. agricultural land. Even nuclear is a viable option based on how you compare carbon and related pollution to nuclear pollution, including risks like spills and meltdowns (damage x probability).

    The ease to switch to non-fossil fuels is really the only viable argument for total pollution.

    Of course, a real calculation should estimate all indirect inefficiencies such as fuel transport and amortize all non-unit costs such as the pollution cost to build and maintain the car and the infrastructure around it including oil wells, power stations and even the extra road maintenace because of fuel trucks driving on the road. However, this probably won't change the argument that the main gain of electric vehicles is the flexibility to switch power sources.

    (2) Where does the pollution go to?

    We can weight pollution by location. For global warming this is not so important, although carbon dioxide near a sink (forest, ocean) might be absorbed quicker than far away from a sink, but in general a greenhouse gas is a greenhouse gas. For health considerations however, it makes a huge difference for pollutants like nitrogen oxides and micro particles (http://en.wikipedia.org/wiki/Motor_vehicle_emissions#Main_motor_vehicle_emissions). In a dense city they cause much more trouble than over the ocean or in rural areas, both because of concentration of pollutants and of people.

    For this equation, electric wins hands down by shifting the pollution from the population center to the location of the power plant.

    tl;dr TFA completely misses the point by focusing on comparing current pollution to current pollution, ignoring the environmental benefits of shifting pollution from cars to power plants, which are both less harmful by being out of the way and by offering a feasible path to clean energy sources.

  10. Re:Marketing babble galore on Ask Slashdot: How Will You Update Your Technical Skills Inventory This Summer? · · Score: 2

    I switched to python around 10 years ago and never looked back. People who think python is all new and shiny now are missing a lot of history - 10 years ago python was almost 10 years old and already at version 2.1.

    The language has evolved into an (IMHO) extremely elegant platform for >90% of my needs, from scripting and data processing to web applications. I especially like the way that decorators and generators allow elegant expression of many functions. Dynamic ("duck") typing has drawbacks (especially IDE support and compile-time checking) but this is lessened somewhat with pyling and unit testing, and it makes a lot of code so much more elegant than e.g. java, where you spent half your time and lines of code working around limitations of the type system. Obviously, python is not perfect. The whitespace is sometimes annoying and packaging is a mess, but at least they're working on the latter.

    Besides python, I use R for statistics and C if things need to go fast, and for the latter python makes it really easy to integrate C and python code.

  11. Re:Oh, gag me. on Why Engineering Freshmen Should Take Humanities Courses · · Score: 1

    Nope. Students party before the graduation, but after that, they're no longer students.

    Students party after, and alumni before, the graduation.

    Good grammar (afaik, not certain on second comma), but horrible style :-)

  12. Re:Net Energy Use? on Solar-Powered Boat Carries 8.5 Tons of Lithium-Ion Batteries · · Score: 1

    Nice try.

    http://en.wikipedia.org/wiki/T%C3%BBranor_PlanetSolar
    Displacement: 85 tons, of which >10% batteries and "very limited" cargo capacity
    Engine max power: 140 kW (2x60+2x10)

    https://en.wikipedia.org/wiki/Axel_M%C3%A6rsk (to pick something big but not brand new)
    Tonnage: 109.000 tons deadweight
    Engine: 56,800 kW

    So the "proof of concept" is a ship that is a good 1000 times smaller and has 500 times less engine power.

    Was his solo rowing across the Atlantic a proof of concept as well, evoking a future in which the unemployed hordes will be rowing container ships across the ocean?

  13. Re: You keep using that word... on Proof Mooted For Heisenberg's Uncertainty Principle · · Score: 4, Informative

    http://dictionary.reference.com/browse/moot says:

    verb (used with object)
    4. to present or introduce (any point, subject, project, etc.) for discussion.
    5. to reduce or remove the practical significance of; make purely theoretical or academic.

    So meaning 4 seems appropriate. Strange that a word simultaneously means to introduce it and to remove it from consideration, but it is a pretty old word I think so it has probably evolved quite a bit.

    Origin:
    before 900; Middle English mot ( e ) meeting, assembly, Old English gemt; cognate with Old Norse mt, Dutch gemoet meeting. See meet1

  14. Re:What the hell is the point of this anyway? on The Security Risks of HTML5 Development · · Score: 1

    Exactly. I have a web application that is essentially a front end to an API. Lots of calls return numbers that have value labels. Having some of these labels stored client side can prevent a lot of round trips.

  15. Re: As the song asks... on Ask Slashdot: Is an Online Identity Important When Searching For Technical Jobs? · · Score: 5, Funny

    If your idea of "having an online presence" is posting everything twice so you double your 'presence', I would only hire you for marketing ;-)

  16. Re: Geotarding? on Google To Buy Waze For $1.3 Billion · · Score: 1, Troll

    Sorry, I messed that one up big time! It should be:

    Well, if you live in Israel, Google maps doesn't have streetnames for almost half of your capital, or for your second largest city. Nor, for that matter, for the fourth and fifth largest city in your country.

    And if you deny that those cities are in your country, could you kindly inform your government so that they can withdraw their troops?

  17. Re: Geotarding? on Google To Buy Waze For $1.3 Billion · · Score: 0

    Well, if you live in Israel, Google maps doesn't have streetnames for almost half of your capital, or for your . Nor, for that matter, for the fourth and fifth largest city in your country.

    And if you deny that those cities are in your country, could you kindly inform your government so that they can withdraw their troops?

  18. Re:Grandfather but still got it (partially) wrong on Gaming Roots: MUD and the Birth of MMOs · · Score: 1

    You should try Vendetta Online. It's an indie space MMORPG where PvP and PK is central to gameplay. Death is cheap in most cases but if you're carrying around special equipment or cargo it can be quite a setback.

    And yes, it runs linux :-) [and windows, mac, android, and ipad]

    (actually, its development pre-dated EVE but it is a very small shop so things move a lot slower. The player base is small but very involved, and you can find the lead dev responding on the forums, making it a nice environment)

  19. obligatory non-xkcd on Why Your Users Hate Agile · · Score: 4, Insightful
  20. Re:G'DAY MATE on Beer Fridge Caught Interfering With Cellular Network · · Score: 1

    I was there last week, not a Turkish gun in sight. But I would still advice against charging it, it is way too hot at the moment and there are too many Israeli tanks :-)

  21. Re:Dictator hating free speech, news at 11. on Turkish PM: "To Me, Social Media Is the Worst Menace To Society." · · Score: 2

    Political Science is divided on how to define "democracy". At the minimum, it has some reasonably level of suffrage to elect the body or bodies that make generally binding decisions (aka laws). However, many scholars argue that a democracy also requires

    This does *not* mean that a law is necessarily based on the (represented) consent of the majority of the population or even of the voting population, as all electoral systems have some sort of misrepresentation of the population, going from the extreme of single member first-past-the post districts (USA, UK) to the most proportional representation of single district PR systems (Netherlands)

    Note that democracy is a separate concept from "rule of law", but it is hard to imagine democracy functioning without the rule of law. In essence, the rule of law means that the law also applies to the rulers (and hence to the enforcement agencies). So, the example of a ruler killing people without trial is more of a breach of rule of law than of democracy. Obviously, it is possible to make a law that allows certain people to be killed without a (civil) trial, as is not uncommon in military law or slavery systems, and apparently American citizens with foreign sounding names in the wrong place at the wrong time are also subject to this process...

    *) even the Netherlands (generally regarded as the most proportional electoral system) has some misrepresentation because of the granularity of MP seats: votes for parties that don't get a single seat are 'wasted' entirely, and remainders are distributed in a complicated way that can in principle allow a majority in parliament to represent a minority of votes. However, this is nowhere near the level of misrepresentation that can occur in SMD systems (where 26% of the vote can capture 51% of seats) or even worse in multi-party SMD systems with first-past-the-post (plurality), where in theory an infinitismal small amount of votes can capture the majority given infinite contenders -- and in the UK the majority party in parliament frequently had a minority of votes cast for it.

  22. Re:Dictator hating free speech, news at 11. on Turkish PM: "To Me, Social Media Is the Worst Menace To Society." · · Score: 1

    Of course, you could also say that Athens (as most greek city states were not democracies at all but rather dictatorships or oligarchies) was not a democracy because they didn't give the vote to either women or slaves. In fact, most "western" democracies only had universal (including female) suffrage for the past 50-100 years or so, with the last swiss canton finally joining ranks in 1990 (!). Before the first world war, every democracy that I know of had various restrictions on suffrage based on race, gender, and/or property.

  23. Re:Nice idea, wrong problem on Electric Car Startup 'Better Place' Liquidating After $850 Million Investment · · Score: 1

    Gas in Israel is normal price form a european perspective, actually a bit cheaper than expensive countries like finland or the Neherlands.

    http://www.brandstofprijzen.info/brandstofprijzen-europa.php
    (it probably went up a bit because the shekel appreciated, but IIRC it is a bit above NIS 7, which is indeed around 1.50 euro. )

  24. Re:Nice idea, wrong problem on Electric Car Startup 'Better Place' Liquidating After $850 Million Investment · · Score: 4, Interesting

    This is even more so for Israel, where the longest drive you can make is from the Golan heights all the way down to Eilat, which is just about 300 miles. The borders in the North are closed (Syria and Lebanon) and most Israeli have no intention whatsoever to drive to Jordan or Egypt, and the time to cross the border is at least two hours anyway so that is probably time enough to charge your car. As regards private transportation, Israel is practically an island with 99% of Israeli citizens only ever leaving the country by air.

    So, Israel is the perfect testing ground for a charging-based electric car park, and battery swapping makes a lot less sense there.

    Coupled with the strategic value of being less dependent on oil while not having relations with the biggest oil producers, and the fact that solar makes a lot of sense in the middle east, I hope that another company with a more sensible model will succeed.

  25. no free choice for gov't info like speed limits on White House: Use Metric If You Want, We Don't Care · · Score: 5, Informative

    I agree that no laws should be passed that force e.g. a supermarket to use specific weights or measures. If people are annoyed by the choice of a supermarket they can bring their business elsewhere.

    However, the "free choice" argument does not work for monopoly players, especially the government itself. The last time I was in the US, miles were used in the interstate system to indicate both distances/exit numbers and maximum speeds. You can't choose to pick the other road that goes the same place but uses metric, because there is no real competition in the road network.

    I don't know whether other official communication of the state(s) uses metric or not, I could imagine many laws and forms that refer to land area, volumes of water, weight (e.g. of cars) that could use either non-metric or metric. They can't hide behind a "free choice" argument there, and a real "bimetric" system requires the government to provide information, like speed limits, in both systems, just like a blingual government publishes laws etc. in two languages.