> -----Original Message-----
> From: SRU (Search and Retrieve Via URL) Implementors
[mailto:[log in to unmask]]
> On Behalf Of Peter Noerr
> Sent: Wednesday, October 26, 2005 11:56 AM
> To: [log in to unmask]
> Subject: Re: federated search
> 
> >
> > Rob is adding another level of complexity often known as a centroid.
> >
> > Matthew
> >
> >
> 
> I've never heard this function called a 'centroid' before. "Database
> discovery" or similar or even "index concatenation", but no
"centroids".
> Do
> you have a reference? Or will I have to do a metasearch for it?

Yep, centroid is the word for the collection of index terms that
describe the records in a database.  I first ran into it in Chris
Weider's Whois++ work.

"The centroid of a server is comprised of a list of the templates and
   attributes used by that server, and a word list for each attribute.
   The word list for a given attribute contains one occurrence of every
   word which appears at least once in that attribute in some record in
   that server's data, and nothing else."

From
http://www.ifla.org/documents/libraries/cataloging/metadata/rfc1913.txt

Ralph