vigna - Slashdot User

Submission + - Google is sending out blankets [sic] to open-source developers 5

Submitted by vigna on Friday May 03, 2013 @09:14AM

vigna writes: A few weeks ago I received an email from Google’s Open Source Programs Office. My work on open-source libraries (fastutil? MG4J? Sux4J? who knows) had been recognised. So I got $175 to spend on the Google store (wow, that's generous!) and I had to give my address to receive a "special thank you gift". After a couple of weeks, a large FedEx package arrived. It contained a *blanket*.

Yes, you read it right the first time. Google is sending out polyester blankets as a special gift to open-source developers.

To me, that's a bit weird.

Comment Well, as one of the authors... (Score 2) 216

by vigna on Thursday November 24, 2011 @06:33AM (#38156620) Attached to: 4.74 Degrees of Separation on Facebook

...I made three days ago a submission with the correct number (3.74). /. couldn't care less. On average the degrees are 3.74, and this is why our paper is called "Four degrees of separation". 4.74 is the distance, which is one more than the degrees of separation. Unfortunately sociologists decided to count the "intermediaries" (so if we are friends, our degree of separation is zero), whereas computer scientists count "hops" (so if we are friends, our distance is one). This generated a lot of confusion. But, just to be clear, no, we did not round 4.74 down to 4; we rounded 3.74 up to 4. :)

Submission + - Four Degrees of Separation (facebook.com)

Submitted by

vigna

on Tuesday November 22, 2011 @03:49AM

vigna writes: "Facebook has just released two studies (I've been involved in one of them) about the structure of the Facebook graph. Using HyperANF, an algorithm for estimating the distance distribution of very large graphs developed at the Laboratory of Web Algorithmics, we have been able to estimate accurately the average degree of separation on Facebook... and it's just 3.74 (one less than the average distances, which is 4.74). So the play "Six degrees of separation" was a little bit pessimistic. The degree distribution of Facebook has been unveiled, too.

The story has been picked up by the New York Times, but alas, they mistook the average distance for the degrees of separation."

Submission + - PageRank has been rediscovered for 50 years

Submitted by vigna on Wednesday March 10, 2010 @07:43AM

vigna writes: A recent post on Slashdot argued that PageRank, the algorithm original developed by Sergey Brin and Larry Page in 1998 to rank web pages in Google, has a precursor in Leontief's input-output economic theory (1941). The link, however, is very weak, as Leontief is just interested in a pricing that makes an economy stable. Much more surprising is that Seeley in 1949 proposed to rank children popularity recursively, using their reciprocal "I-like" relationships, exactly as PageRank does. Wei in 1952 proposed to rank sport teams in the same way using the score of matches as "I'm-better-then" relationships, and Katz defined in 1953 its famous social index, which is exactly PageRank modulo a matrix normalization. The mathematics of all these contributions has been unified in a recent paper that tries to show how spectral ranking has been rediscovered over, over, and over for more than 50 years.

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