Re: Dublin Core summary article

Dan Brickley (
Sun, 1 Feb 1998 17:40:13 +0000 (GMT)

On Sat, 31 Jan 1998, Jim Whitehead wrote:

> There is a very good article in the January, 1998 issue of D-Lib magazine
> which gives a summary of the work to date on the Dublin Core bibliographic
> metadata set.
> "The Dublin Core and Warwick Framework", Harold Thiele

Shamless plug time... the article on centroids/CIP-based query routing
isn't too bad either... Same issue, previous article:

"Cross-searching Subject Gateways: The Query Routing and
Forward Knowledge Approach".


random snippet for context:


The increased availability of networked databases is rapidly
leading to the situation where many users will need to query
multiple distributed databases in order to locate all of the
information that they require. Unfortunately, this has
traditionally meant that the end user has to either query each of
these databases individually or else use a standardized search and
retrieval protocol client (such as a Z39.50 [25] client) that has
been pre-configured to search a set of remote database servers. The
first of these places the burden of locating the remote databases
and learning each database's query interface on the end user. The
second means that remote database servers and network links are
often unnecessarily used even when their databases holds no
information relevant to a user's query.

What is needed to improve this situation is for the remote
databases to be able to let each other have some knowledge of the
sort of data that they hold in advance of the end user's query
being processed. This is known as "forward knowledge" and can be
used to provide "query routing" from a single initial database
server on to other servers that are likely to hold relevant
information. If this forward knowledge contains information about
the query language in use at the remote databases, the end user's
client might also be able to translate the user's initial query
into a form that is appropriate for the remote server and translate
the results into a standard display format.

The Common Indexing Protocol (CIP v3) [26] is intended to fulfill
this need for forward knowledge to permit efficient query routing
to take place. CIP v3 is based upon the concept of centroids, which
stems from the WHOIS++ directory access protocol [27] (indeed
WHOIS++ is known as CIP v1). A directory access protocol such as
WHOIS++ is designed to allow queries to be made against a directory
database of people or services (so-called white pages and yellow
pages services respectively, named after the two types of telephone
directories in the USA ), which can be useful for allowing email
addresses to be looked up for example [28]. Whilst CIP v3 itself is
not tied to any particular database or access protocol, in order to
understand the basic principles behind CIP v3, this paper will
first outline the simpler generation and use of centroids in