Deriving Semantic Meaning From Google Results

prostoalex writes "New Scientist talks about Paul Vitanyi and Rudi Cilibrasi of the National Institute for Mathematics and Computer Science in Amsterdam and their work to extract meaning of words from Google's index. The pair demonstrates an unsupervised clustering algorithm, which 'distinguish between colours, numbers, different religions and Dutch painters based on the number of hits they return', according to New Scientist."

Comments

The elephant in the living room.

[Eunuch]

These kinds of articles never seem to get a very basic problem--natural languages. English is full of words that trip even humans. "Right" the direction versus "right" the judgement is a good example. In wartime something as simple as that may have lead to death. It's the elephant in the living room. Huge, important problem that nobody wants to talk about. There are alternatives, such as lojban which can be parsed like any computer program.

The article mentions English-Spanish translation. When one language is ambiguous (from a bit of Spanish I had in HS I'm guessing English is far more ambiguous), there is no hope of easy translation. And it's worse because the bigger application may be translating the many English pages (ambiguous) to Spanish.

Re:The elephant in the living room.

[freralqqvba]

Well obviously the technology is not perfect yet. However, none of the problems you bring up are particularly insurmountable (as long as you aren't excepting the AI to be BETTER at parsing languages than people). Yes, words are ambiguous, and yes humans can fail at parsing them, ergo computers probably will too. That's just a fact, we're not going to achieve perfection. Still, this could be a pretty major step forward (well, not that this is the first time something like this has been tried - but the base premise seems sound) by using google the elephant of a problem you mention can be partialy mitigated. Google gives enough context around a word that ideally, when the word to be translated is also surrounded by context its meaning amoung alternate meanings can be discovered without giving an overly ambigous translation.

Limitations of NGD (Normalized Google Distance)

[G4from128k]

Although very clever, NGD (Normalized Google Distance) misses alll higher-order relationships and does not even distinguish between different categories of pairwise relationships. For example, NGD might assume that "Bush" & "Iraq" had the same relationship as "Slashdot" & "Geek" because the two word pairs co-occur with similar frequencies.

More interesting are analyses on n-Tuples (co-occurences and orderings of n-words at a time). Anyone who does ER (Entity-Relationship) diagrams for relational databases will appreciate that many relationships involve multiple entities that are decomposable into pairwise relationships.

Another limit is that Google is atrocious on its estimates of the number of hits. The actual number of hits is only fraction (about 60%?) of the estimated from my experience. This suggests that Google has a pairwise estimator built in that may be only partially empirical. If Google simply reports an estimated number of hits based on products of probabilities, then their is no information about the pair in the NGD. Obviously, these scientists have gotten useful results, but NGD may not be as good an estimate of the co-occurence of the words as the scientists assume.