Re: SKOS and MeSH qualifiers

On Mon, 11 Jul 2005, Leonard Will wrote:
>
> In message
> <F5839D944C66C049BDB45F4C1E3DF89DEE9E59@exchange31.fed.cclrc.ac.uk> on
> Mon, 11 Jul 2005, "Miles, AJ (Alistair)" <A.J.Miles@rl.ac.uk> wrote
> >I think I understand the problem (please correct me if I haven't), how
> >about this for a solution ...
> >
> >The fundamental statement that is being made in document metadata is
> >something like, 'the subject of document X is (concept Y qualified by
> >concept Z)'.
> >
> >The crucial bit is the parentheses.
>
> In general none of the terms need be considered as "qualifying" any
> other - they are brought together as equals.
>
> Examples of compound strings (subject headings taken from the Library of
> Congress catalogue) are:
>
> Leukemia -- Animal models -- Congresses.
> Leukemia -- Biography -- Fiction.
> Leukemia -- Chemotherapy -- Data processing.
> Leukemia -- Environmental aspects -- Massachusetts. Cape Cod.
> Leukemia -- Patients -- Australia -- Biography.
>
> With other schemes of  subject headings and classification (such as UDC,
> Bliss, and to a lesser extent Dewey) you may need to express
> pre-coordinated subjects with even more component concepts, such as:
>
> "manufacture of packaging products from recycled waste paper"
> "local authority provision of social services for families of
> disadvantaged children"
> "user studies for the investigation of the effectiveness of computerised
> information retrieval systems"
>
While I certainly agree with Leonard's desire to find a solution (if
deemed appropriate) for the more general case of MeSH, LCSH and other
schemes, I do not agree with his statement (in the case of MeSH):

> In general none of the terms need be considered as "qualifying" any
> other - they are brought together as equals.

With MeSH, while the "qualifiers" may be full MeSH descriptors in their
own right, they are when used as qualifiers playing the role of
qualifying a MeSH descriptor and are thus not equal to the term they are
qualifying. A document indexed with term T and qualifier Q must be found
if searching for

	term T
	term T with qualifier Q
	qualifier Q

but _not_ when searching for

	term Q
	term Q with qualifier T

(admitting of course that the document might _also_ be indexed with term
Q, etc. but, for the sake of argument, not in this case). Is this the
same for LCSH? Taking one of Leonard's examples,

	Leukemia -- Animal models -- Congresses.

would it be appropriate to find a document so indexed if searching for
"Leukemia -- Animal models", or would that be considered a different
pre-coordinated term?

It might be useful to try to define the requirements of MeSH and LCSH in
more abstract terms to see if indeed a general solution is appropriate.
With MeSH, the qualifiers are only one level deep and have a minimum
cardinality of 0 and no maximum cardinality at that level; with LCSH
(and others?) it looks, from Leonard's examples, as if the level of
depth is arbitrary but that at each level the minimum cardinality is 0
and the maximum cardinality is 1. More graphically:

MeSH                    LCSH
----                    ----
term T                  term T
    refinement A            refinement A
    refinement B                refinement B
    refinement C                    refinement C
    ...                                ...
    refinement n                           refinement n

Documents indexed with these refinements should be found if a search is
done for term T alone or with any one refinement from each level of
depth, with no restriction on depth of refinement. It's possible that a
general solution might prove too complex, given that (if my analysis is
correct) it would need to accommodate infinite levels of refinement and
unrestricted cardinality at each level.

-- Robert

--------------------
Robert Watkins
rwatkins@foo-bar.org
--------------------

Received on Tuesday, 12 July 2005 10:35:02 UTC