Hi Nitin,

I'm assuming you're asking about Latent Semantic Indexing and similar.
This may not be the best place to ask about this. Not sure where else
to suggest though.

If I understand your quesion correctly, the basic idea is that you
take a document (usually text but it could also be an image, video,
whatever) and create a meaningful vector from it. With a text document
you could create the vector by specifying each word in your vocabulary
as a dimension and defining the position in that dimension as the
number of occurences of that word. You can then treat the Euclidian
distance between documents as a measure of similarity. Similar
documents are clustered together.

With images you need different techniques to create the vectors.
Different vector creation algorithms create different measures of
similarity (colour, shape, etc).

I wouldn't say that semantic indexing methods are "different" from the
semantic web, because I see them as overlapping concepts. From my
perspective the semantic web comprises of many approaches, both
top-down (centralised interpretation of meaning like LSI) and
bottom-up (manual meta-tagging of data through mark-up, linking,
microformats, etc.)

Does that help at all? If anyone has corrections, or more to add,
please pile in... I'm wearing my flame-retardant underpants  :)


Rich



2009/4/1 nitin gopi <nitdaii...@gmail.com>:
> hi all,
>        I want to know everything about semantic vectors. I want to know how
> does it indexes the documents such that the results produced are
> semantically better than normal search. I also want to know how it is
> different from semantic web, which uses the concept of ontologies and
> metadata. It would be very helpful if somebody mail me all the study
> material related to it?
>
> Thanking You
> Nitin
>



-- 
Richard Marr
richard.m...@gmail.com
07976 910 515

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