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Domain: edmonton.ab.ca

Stories and comments across the archive that link to edmonton.ab.ca.

Comments · 7

  1. Re:No suprise by Peyna · · Score: 1 · on Russian Mock Mars Mission

    You mean something like this?

  2. History of Meccano by MuMart · · Score: 1 · on Mechanical Computing
    For the interested:

    Meccano History

  3. Re:Anyone bought that X-Arcade cabinet? by PantyChewer · · Score: 2, Interesting · on Play Classic Video Games In NY, At Home
    My Cabinet cost me around $1200 canadian to build, and that includes the TV and computer unlike the X-Arcade. The X-Arcade is for people with more money than time. I found building the thing at least as much fun as playing on it.

    As mentioned BYOAC(Build Your Own Arcade Controls) Is a great site for MAME cabinet related information.

  4. Re:remember Erector sets? by MatthewB79 · · Score: 1 · on VIA-based Mobile Robot Design For Download

    Ummm, there has never been a time that you could not buy Meccano Erector Sets. Though the original Meccano factory did shut down, other factories in France and Argentina continue to build and sell the sets under a different company name: "Erector". Many of the newer sets have updated (read: plastic) pieces, but you can still get them at most real toy or hobby-type stores and you can (of course) order them online.

  5. Play monte hall! by Booker · · Score: 2 · on The Three Hat Problem
    The monty hall problem is a great one... you can play it here.

    Oh, and by the way, you should always switch. :)

    Here's another one I like, but in a differetn (physics) vein - a man is in a boat holding a cement block. He throws it overboard. Does the lake level go up, go down, or stay the same?

    ---

  6. Re:OffTopic by Nickoty · · Score: 1 · on Fox Moon Special Response
    Bloody hell yes it is! Ok, so maybe we've misunderstood each other. I'll state my stand again, lamely obvious:

    By sqrt() I mean the root sign, the one that loks somewhat like \/"""

    x^2 = 9 &lt==&gt x=sqrt(9) would be wrong, missing one solution

    x^2 = 9 &lt==&gt x=&plusmn sqrt(9) would be correct

    sqrt(9) = -3 would be wrong

    sqrt(9) = 3 would be correct

    sqrt(9) = &plusmn 3 would be wrong

    About your definition; that's not the 'square root'. It's a general case, and the sign convention should have been pointed out in that book (I don't have it). As this semi-decent page says, "If a is any nonnegative real number, then its square root is the nonnegative number whose square is a" and "Unlike square roots, the cube root of a number may be negative".

    Now of course I didn't find some real good web references backing me up and explaining the thing once more, so we can see where we differ. Misunderstandings are easier to avoid using paper (refering to GIFs on a real page) than ASCII art. Anyway, here are a few:


    "[...] when we take the square root of a value, we want the principle square root. For real numbers, that is the positive value. "
    http://forum.swarthmore.edu/dr.math/problems/andre w11.24.98.html

    "[...]the square root sign denotes the positive square root"
    http://www.stockportmbc.gov.uk/curriculum/maths/ma ths03.htm

    "Positive numbers have always have two square roots, one positive and one negative. The radical sign, , always denotes the positive, or principle, square root. Zero only has one square root, 0 itself. Negative numbers do not have real number square roots.
    5 is the square root of 25 because 5 5 = 25. 5 is the Principle Square Root because it is positive."     http://epsb.edmonton.ab.ca/schools/crestwood/real_ numbers_1.3.html

    Perhaps I should have said 'The radical sign' or something instead of sqrt()?

  7. Possible misunderstanding of stream ciphers... by Christopher+B.+Brown · · Score: 3 · on Public-key Based Streamed Encryption?
    See:

    Remember stream ciphers != block ciphers.

    RC4 and SEAL are notable stream ciphers; the usual distinction between a stream cipher and a block cipher is that block ciphers work with "blocks" (or "packets") of material, whereas stream ciphers work with far smaller "blocks," commonly a single word or byte. The pathological example of a stream cipher should encrypt bit-by-bit; on computers with word sizes of 32 bits, it would make considerable sense to treat a 32 bit word as the "atomic unit" being encrypted.

    Whether the "atom" is a bit, byte, or word, the critical issue is that the unit of encryption is liable to be a whole lot smaller than the 56 bytes one might have in an Ethernet packet...