Tuesday, May 10, 2011

Programmer Anonymous notes, 111

"Marry Skype's software with the Xbox Kinect and an HD television set, and Microsoft can make a powerful argument for getting into millions of living rooms." Tim Webber commenting on Microsoft's acquisition of Skype.

A lattice on a tesseract with a dimension of 4x4x4x4 has 256 points. If each point is associate with a data value (1 bit), 256 bits are accomodated. Tesseracts have 24 cubic faces, in this case with a dimension of 4x4x4. If a parity bit is assigned to every 4-tuple  in the tesseract (12 cubes of parity bits, one cube for each pair of faces), there will be 6*4^3 = 768 parity bits. So 1024 bits can encode 256 data bits with the ability to detect and correct many transmission errors. How many? This is not as efficient as some Hamming codes, but its structure is beautiful.

Saturday, May 7, 2011

Programmer Anonymous notes, 110

ilearnedtoprogram.com - Share the Story of Why and How You Learned to Program

"in college, when I realized I could have a big impact on the world by building software with a focus on humanity." - Vanessa Hurst
"because I believed (and still do) that it's one of the best skills to have in order to change people's lives for the better." Alyssa Daw
"when I wanted a piano and got an Atari -- programmed the keys to make sounds." Katie A. Siek
"because I wanted to make interactive electronic literature." - Zuzana Husarova
"because I wanted to build cool things. Now that's my job." - Alex Gaynor

Multiplayer High, by Douglas Thomas and John Seely Brown

Listen to anyone talk about schools today: classical education just can't keep up. In the digital generation's world of constant change, most schooling is profoundly boring. But what else is possible?

About this essay,  jdparadise comments:
So, in a word, give or take: Montessori.

Shannon's Law, by Cory Doctorow
A recent short story for anthology. Claude Elwood Shannon (April 30, 1916 – February 24, 2001) was an American mathematician, electronic engineer, and cryptographer known as "the father of information theory".[1]

The title is a reference to the Shannon–Hartley theorem:
...a bound on the maximum amount of error-free digital data (that is, information) that can be transmitted with a specified bandwidth in the presence of the noise interference ...
The story includes a short cryptogram, and a shorter cryptic numerical puzzle (not the same thing). I have reason to believe (aesthetic reason) both wouldn't be hard to crack.

Doctorow has also written about metacrap.

Alan Turing Statue Passes Dog's Turing Test:
Border collie is baffled by stubborn old man who refuses to play. Said old man is actually a statue of Alan Turing, which has seemingly passed the dog's own meager Turing test.

Robots learning to share

Robot Evolution: EPFL and the University of Lausanne team up to explore Hamilton's law of kin selection. Published in PLoS on May 3rd, 2011, biology and robotics come together to help understand how altruistic genes get passed on from one generation to the next. To learn more about the labs: http://lis.epfl.ch and http://www.unil.ch/dee/page6763.html

Once the team was comfortable with the virtual evolution environment it had set up, it added a new twist: It allowed the robots to share food disks with each other. If Hamilton's hypothesis was correct, "successful" virtual robots were likely to be those that were closely related and shared food with each other; that would help to ensure that at least one of them -- and some of the genes of both--would make it to the next round. (Two robots with a modest amount of food disks would both be more likely to be cut from the simulation, but if one robot gave all of its food to a second robot, that second robot would likely make the next round.) And indeed, altruism quickly evolved in the simulation, with greater food-sharing in groups where robots were more related, the researchers report online today in PLoS Biology. The more closely related the robots, the quicker they cooperated. "It shows how general the [theory] is, whether you are an insect, a human or a robot," says Floreano.