Hi Stephen and all,
We’ve made an intentional decision for the V/FRBR project to not use the
concept of an aggregate work. The many-to-many nature of Expression to
Manifestation for our need adequately models the fact that two symphonies were
released on the same disc (for example). For our purposes, there’s no practical
(or even semantic in my opinion) benefit to calling those two symphonies by two
different composers an aggregate Work.
Like others have commented, I also have reservations about the aggregate notion
in FRBR as a whole. That has fed into the practical decisions our project has
made.
Jenn
On 10/17/10 9:53 PM, "Stephen Hearn" <s-h...@umn.edu> wrote:
For those who argue that FRBR defines aggregates as works, I wonder if this is
too atomic an approach. If there is an aggregate FRBR work whose contents are
expressed in an aggregate FRBR expression and embodied in an aggregate FRBR
manifestation, couldn't one reasonably argue that the manifestation is really
only the embodiment of that aggregate work, and is rather a container for the
other, individuated FRBR works that Variations is working with? Does Variations
enable the description of the single aggregate FRBR work that a given
manifestation arguably represents?
For example, a search on "octubafest" identifies two "work results" with that word in the
title, but they are individual pieces (Octubafest march and Octubafest polka). Wouldn't FRBR consider the
aggregation manifested as "Octubafest 1981" and the others like it to be works as well?
That said, I've long considered the notion of aggregates as FRBR works to be
problematic, so I see a lot to admire in the Variations approach.
Stephen
On Sun, Oct 17, 2010 at 3:04 PM, Riley, Jenn <jenlr...@indiana.edu> wrote:
Dear Bernard and List,
My apologies for not responding sooner; I'm impossibly behind in reading
listserv email. Comments below.
Riley, Jenn wrote:
The Variations/FRBR [1] project at Indiana University has released
bulk downloads of metadata for the sound recordings presented in our
Scherzo [2] music discovery system in a FRBRized XML format.
Before digging into this any further, one question: How is the
linking between works and expressions effected? On first inspection,
I find nothing in the expression data that would indicate the work.
The XML format that defines this data (our project "efrbr" definition; more information at
<http://www.dlib.indiana.edu/projects/vfrbr/schemas/1.0/index.shtml>) doesn't have the concept of a "record,"
just "entities" and "relationships". The XML wrapper can include any combination of entities and
relationships - there's no requirement that it be, say, Work-centric (show one Work and all the other FRBR entities with
relationships to that Work) or Manifestation-centric (show one Manifestation and all the other FRBR entities with
relationships to that Manifestation), though you could easily use the format for either of those purposes. Therefore the big
.xml file that has all the Expression data doesn't *have* to have relationships between Expressions and Works to be valid. We
simply chose to arbitrarily break the data into individual XML files by entity and relationship type, since there was enough
data we knew we had to split it up somehow to keep the file size to something remotely manageable, so this seemed logical.
It's just the raw data - a system using it could index and store and update it however it likes. All the relationships are
there, though, spread across all of the files. Relationships between Works and Expressions can be found in the file
realizedThrough.xml.
I suspect the link to be via the file realizedThrough.xml, because
between manifestation and expression, there's the file embodiedIn.xml
which seems to be the link between the two. However, I'd have expected
the relationship between E and M to be 1:n, yet it seems to be
the opposite.
Can you elaborate on this matter?
You've switched to talking about the relationship between Expression and Manifestation rather than Expression
and Work, so I'm a bit confused as to what you're asking, but I'll give it a shot. You're correct that
embodiedIn.xml lists relationships between Expression and Manifestation. (Note "realized through" and
"embodied in" are terms right out of the FRBR report to describe these relationships.) The
relationship between Expression and Manifestation is n:n (many to many). A given Expression be embodied in any
number of different Manifestations, and a given Manifestation may embody any number of different Expressed
Works. In embodiedIn.xml, each element <efrbr:embodiedIn> describes the relationship between one
Expression and one Manifestation. This statement, however, doesn't mean that's the only Manifestation of that
Expression, or the only Expression that appears on that Manifestation. Instead, these are just tiny statements
of fact. To find all the Expressions on a given Manifestation (which is only one of the many questions one
might want to ask of this data), you'd need look for all of the <efrbr:embodiedIn> statements that have
the URI for the Manifestation you care about in the @target attribute. You can see some of these right at the
beginning of the file:
<efrbr:embodiedIn
source="http://vfrbr.info/expression/1"
target="http://vfrbr.info/manifestation/1"/>
<efrbr:embodiedIn
source="http://vfrbr.info/expression/2"
target="http://vfrbr.info/manifestation/1"/>
<efrbr:embodiedIn
source="http://vfrbr.info/expression/3"
target="http://vfrbr.info/manifestation/1"/>
<efrbr:embodiedIn
source="http://vfrbr.info/expression/4"
target="http://vfrbr.info/manifestation/1"/>
To find all the Manifestations a given Expression appears on, you'd look in the data
for all the <efrbr:embodiedIn> statements that have the URI of the Expression
you care about in the @source attribute. Basically it's a whole bunch of very atomic
data that can be combined in any way to answer all sorts of different questions: What
Works are by this Person? What Manifestations were published by publisher X? What
Works were performed by Corporate Body X (i.e., which Works have Expressions that
have realized by relationships to that Corporate Body)? Ad infinitum...
Many thanks,
B.Eversberg
Hope this helps.
Jenn
========================
Jenn Riley
Metadata Librarian
Digital Library Program
Indiana University - Bloomington
Wells Library W501
(812) 856-5759
www.dlib.indiana.edu <http://www.dlib.indiana.edu>
Inquiring Librarian blog: www.inquiringlibrarian.blogspot.com
<http://www.inquiringlibrarian.blogspot.com>
========================
Jenn Riley
Metadata Librarian
Digital Library Program
Indiana University - Bloomington
Wells Library W501
(812) 856-5759
www.dlib.indiana.edu
Inquiring Librarian blog: www.inquiringlibrarian.blogspot.com