Alistair, in RDA the relationships between works, expressions,
manifestations are defined in terms of access points. The access
points act as identifiers for those FRBR entities. So that's what we
are trying to mimic, in part to see if it works.
LC permalinks identify the MARC record in the LC file. Those are fine,
but there are many many bibliographic records that aren't in the LC
file. (Plus, the MARC record today is a mix of FRBR levels, but that's
another issue.) Basically, we're talking about the same data appearing
in thousands of library systems and no central source of identifiers.
Any library database can have its internal identifiers, but if we want
to share data, we need an identifier that has meaning outside of an
individual system.
If the access point works as an identifier in this way, then what we
need is "permalinks" that represent those access points. In many
(most? all?) cases, that would be the identifier for the authority
record for the access point, IF we had a shared pool of those. These
access points would indeed represent the work or expression.
It's actually quite brilliant. The access points are derived from the
item itself, so there's some chance that two catalogers describing the
same work would come up with the same access point independently. Then
if those access points had URI identifiers, you'd be on your way to
RDF data.
kc
On Thu, Dec 11, 2008 at 2:25 AM, Alistair Miles
<[log in to unmask]> wrote:
> Hi Karen,
>
> Just a quick comment, I understood that "access points" were means of
> identifying an entity for humans. Isn't this separate from identifiers
> which are for use within software, which need not ever see the light
> of day outside software?
>
> Coming up with an author/title "access point" for a work or expression
> sounds like something quite different from coining a persistent URI to
> identify the same work or expression for use within web-based
> information systems.
>
> I understand that LC are creating "permalinks" for bibliographic
> records? I think the "permalink" idea is a great way to tackle the
> need for identifiers. I.e. if each authority created a permalink URI
> identifying each bibliographic entity for which they hold a record, we
> could then use the permalink URIs in our RDF/RDA metadata to link all
> the entities together.
>
> Cheers,
>
> Alistair
>
> On Mon, Dec 08, 2008 at 06:00:17PM -0800, Karen Coyle wrote:
>> A recent discussion on the RDA-L list brought to light some
>> information about FRBR relationships and how RDA creates (or does not
>> create) identifiers for linking between work, expression,
>> manifestation, and item. (WEMI)
>>
>> The key information is in chapter 17, which is only 17 pages long (and
>> a lot of it is examples). What is significant for this project is that
>> links between WEMI consist of "preferred access points" that represent
>> the FRBR entity. For example, there can be an author/title access
>> point that represents the work ("Schumann, Clara, 1819-1896. Scherzos,
>> piano, no. 1, op. 10, D minor"). A expression access point represents
>> the expression of the work ("Blade runner (Motion picture : Final
>> cut"). Some works and expressions have LC authority records, and the
>> ID number of the authority record may be considered an identifier for
>> the FRBR entity.
>>
>> The chapter also shows examples using what I see as "external"
>> identifiers for the FRBR Group1 entities (WEMI). These include the
>> ISBN or music publisher numbers for manifestations, and the
>> International Standard Text Code for works. These external identifiers
>> strike me as problematic for a few reasons:
>> - coverage is uneven: there are many works and manifestations that
>> don't have such a code
>> - coverage is uneven: there are no such codes for expressions
>> - these identifiers come from another information space, and creators
>> of RDA data cannot create or correct them when needed
>>
>> The upshot is that identifying and linking FRBR Group1 entities using
>> these external identifiers is spotty at best, and decidedly not
>> consistent enough to create reliable FRBR relationships.
>>
>> Now for the catch:
>>
>> RDA does not specify "preferred access points" for manifestations or
>> items. So we have no "identifier" for manifestations. (not having one
>> for items is a bit less of an issue, for various reasons). So we can
>> link from:
>>
>> manifestation (with an expression access point) to an expression (with
>> a work access point) to a work
>>
>> But we can't link from an item to a manifestation, nor can we create
>> relationships between manifestations. Well, not with what we have
>> today in RDA.
>>
>> This came up for us in Alistair's analysis of scenario 2, where he
>> used the ISBN for the manifestation identifier. I objected, but in
>> fact there is no actual manifestation identifier to use.
>>
>> I don't really know what to do at this point, but it would be good to
>> try to make use of RDA access points as WEMI identifiers in one or
>> more of the scenarios so we can illustrate the issue. I'll see what I
>> can do, but may need help.
>>
>> kc
>>
>> --
>> -- ---
>> Karen Coyle / Digital Library Consultant
>> [log in to unmask] http://www.kcoyle.net
>> ph.: 510-540-7596 skype: kcoylenet
>> mo.: 510-435-8234
>> ------------------------------------
>
> --
> Alistair Miles
> Senior Computing Officer
> Image Bioinformatics Research Group
> Department of Zoology
> The Tinbergen Building
> University of Oxford
> South Parks Road
> Oxford
> OX1 3PS
> United Kingdom
> Web: http://purl.org/net/aliman
> Email: [log in to unmask]
> Tel: +44 (0)1865 281993
>
--
-- ---
Karen Coyle / Digital Library Consultant
[log in to unmask] http://www.kcoyle.net
ph.: 510-540-7596 skype: kcoylenet
mo.: 510-435-8234
------------------------------------
|
