

Scientist Finds PageRank-Type Algorithm from the 1940s - ca98am79
http://www.technologyreview.com/blog/arxiv/24821/?ref=rss&a=f

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beagle3
PageRank is essentially a version of the "stationary probability distribution
of a discrete markov process" applied to web pages being states and link being
transitions. I remember learning the math back in '96, and it was old then --
perhaps 40 years old.

What is interesting about this finding, is that it was _already_ applied to
evaluating scientific papers and quotes.

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elblanco
Everybody knows about Markov's work in this sense. The reason it worked so
well was not just Google's application of Markov probability distributions,
but their integration with the then predominant search strategy of vector
space models for page retrieval. The key insight Brin and Page had was to
incorporate Markov's work as a scoring metric along with the results from a
vector space search (it's all matrices anyways) and then generalize that to
include other metrics to help weight pages to the top that are more likely to
be what people are looking for.

PageRank != Markov processes only, it's not even just Markov + Vector
retrieval, if it was they'd be good to go and their staff of search quality
engineers would be in the single digits. But Google has a large number of
engineers who's sole purpose is to find ways of tweaking that basic weighting
formula, using the user's query (and a handful of other metrics like custom
search preferences, language, etc.) to float up good pages and sink down bad
pages. I wouldn't be surprised if even Kleinberg's HITS hasn't made it into
the formula in some way.

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pgbovine
very cool, i like how the author didn't do any trollish editorializing like
"lulz brin and page were soooooo unoriginal, omgz pagerank is so not
innovative it's been around for 60 yearz, anybody could've built googlez"

scientific discoveries inevitably build off of prior work, so it's nice to see
this sort of article acknowledging predecessors to seemingly-modern ideas
without denigrating them.

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ruang
Makes you wonder why none of these people made their own search engine.

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wanderr
In the 40's? By the time they would have had an opportunity to apply this to
making a search engine, its unlikely that they would be in a position to drop
everything they were doing and create a startup, assuming they would even
remember the research they did so long ago _and_ realize the insane value of
making a search engine like that.

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chancho
I think ruang was referring to Kleinberger, who applied the idea directly to
web pages, as opposed to scientific journals or economies. He did it only
short while before Page and Brin, and they even cited him. As to why he didn't
make a search engine, I'm guessing it's because CMU is in Pittsburgh.

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neilc
Kleinberg, not Kleinberger, and he's a prof at Cornell, not CMU. I'd guess it
has less to with geography, and more to do with the fact that Kleinberg is a
(brilliant, celebrated) academic who probably wasn't very interested in doing
a startup.

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elblanco
Agreed, basic research is worlds different than business.

