On Wed, Aug 12, 2009 at 1:45 PM, Karen Coyle<[log in to unmask]> wrote:
> Ross Singer wrote:
>>
>> One of the problems here is that it doesn't begin to address the DCAM
>> -- these are 59 properties that can be reused among 22 classes, giving
>> them different semantic meaning.
>>
>
> Uh, no. That's the opposite of what the DC terms are about. Each term has a
> defined range -- so the defined range of creator is Agent. It can only be
> used as an Agent. You don't mix and match, and you don't assign different
> semantics to the same property under different circumstances.
Jason clarified what I meant much better than I did, but I will take
this a step further -- the DC properties have ranges, but only 5 have
a constraint on their domain. So while dct:creator has to point at a
dct:Agent (or some equivalent), where the dct:creator property lives
can be anything.
<dct:Location about="#RhodeIsland">
<dct:title>Rhode Island</dct:title>
<dct:creator>
<dct:Agent about="#RogerWilliams">
<dct:title>Roger Williams</dct:title>
<dct:creator>
<dct:Agent about="#JamesWilliams">
<dct:title>James Williams</dct:title>
</dct:Agent>
<dct:Agent about="#AliceWilliams">
<dct:title>Alice Williams</dct:title>
</dct:Agent>
</dct:creator>
</dct:Agent>
</dct:creator>
</dct:Location>
The definition of dct:title is: A name given to the resource. So
dct:title could be "re: [CODE4LIB] MARC/MODS and Automating Migration
to Linked-Data Standards", "Ross Singer" or "Chattanooga, TN"
depending on what resource we're talking about. Maybe "semantics" is
a poor word choice, but I think "Ross Singer" as a "title of an Agent
resource" or "Chattanooga, TN" as the title of a Location resource
have some conceptual distinctions to "For Whom the Bell Tolls".
The "creation" of Rhode Island also carries a different mental image
than the "creation" of Roger Williams.
It seems like context influences semantics, at least somewhat.
>> Dublin Core is toothless and practically worthless in XML form. It is
>> considerably more powerful when used in RDF, however, because they
>> play to their mutual strengths, namely that in RDF, you generally
>> don't use a schema in isolation.
>>
>
> The elements in Dublin Core are the elements in Dublin Core. The
> serialization shouldn't really matter. But if you need to distinguish
> between title and subtitle, Dublin Core's http://purl.org/dc/terms/title
> doesn't work. What matters is the actual *meaning* of the term, and the
> degree of precision you need. You can't use http://purl.org/dc/terms/title
> for "Mr." or "Dr." in a name -- it has a particular meaning. And you can't
> use it for "title Proper" as defined in library cataloging, because it
> doesn't have that meaning. It all depends on what you are trying to say.
>
Again, Jason did a good job at explaining the difference. Dublin Core
in XML (at least in every example I've ever seen) consists solely of
literals. The values are text, not resources -- so in XML DC, not
only would you be unable to attach, say, birth and death date
properties to Roger Williams, you also wouldn't be able to say who his
creators are.
Going back to "context defining semantics", I don't think it's
unreasonable to say that dct:title does mean "title distinct from
subtitle" if that's the expectation of how dct:title is to work within
your vocabulary/class.
<ex:Book about="http://example.org/ex/1234">
<dct:title>Zen and the Art of Motorcycle Maintenance</dct:title>
<ex:subTitle>An Inquiry into Values</ex:subTitle>
</ex:Book>
The definition of dct:title is pretty ambiguous -- alternately, you
might choose to use dct:title to contain the full title and define
some other property for main title.
Just because title doesn't have a clear definition doesn't mean rules
can't be applied towards it when used in a particular domain (assuming
they conform to 'the name of the resource').
>> This is true. But this is also why I'm asking what is missing in
>> DCTerms that would be available in MODS -- The "win" of RDF is that
>> you aren't contrained by the limits of a particular schema. If a
>> particular vocabulary gets you a fair ways towards representing your
>> resource, but something is missing, it's perfectly reasonable (and
>> expected) to plug in other vocabularies to fill in the gaps.
>>
>
> Exactly. But the range of available vocabularies today is quite limited.
> There are a lot of semantics that are used in libraries that I can't find in
> the available vocabularies. Eventually I think we will have what we need,
> but ... well, yesterday I was hunting all over for a data element for price.
> And the person who needed it didn't want to get into the complexity of ONIX.
> BIBO doesn't have it. DC doesn't have it. RDA doesn't have it. Something
> that simple.
>
Well, Bibo doesn't have it because it has nothing to do with citations.
GoodRelations (http://www.heppnetz.de/projects/goodrelations/) does,
but I admit that it's usage seems rather baroque:
http://www4.wiwiss.fu-berlin.de/bookmashup/doc/offers/0596000278googleOffer6997796095130913016
I'm not sure how you'd do this in MODS, though, either.
> Now I admit that lots of people are inventing bibliographic element sets.
> But if you look carefully at the properties they are defining, the overlap
> isn't all that great. At least, if you don't want to lose meaning. It's
> absolutely key to look at the semantics and the relationships. RDA is
> defining certain properties as having a fixed relationship to an FRBR
> entity. (I'd rather do that in an application profile rather than the
> properties, but that's not my call.) A similar property in DC, without
> making that connection, doesn't have the same meaning because you can't
> distinguish between a title for the work or a title for the expression.
Sure you can.
<frbr:Expression about="http://example.org/e/1234">
<dct:title>Romeo + Juliet</dct:title>
<frbr:realizationOf resource="http://example.org/w/1234" />
<dct:creator resource="http://example.org/i/craig-pearce" />
<dct:creator resource="http://example.org/i/baz-luhrmann" />
</frbr:Expression>
<frbr:Work about="http://example.org/w/1234">
<dct:title>Romeo and Juliet</dct:title>
<dct:creator resource="http://example.org/i/william-shakespeare" />
<frbr:realization resource="http://example.org/e/1234" />
</frbr:Work>
> Perhaps you could create a record format that gives DC terms "title" that
> context, but used alone it does not contain those semantics.
>
But nothing is going to make sense out of context.
> What I WOULD like to see is a good vocabulary of basics -- date, time,
> place, currency, etc etc etc. One place where you know you can go and find
> all of those key building blocks, so you don't have to hunt all over god's
> little acre for something as simple as "price". That would be really useful.
>
+1 to that. I completely agree this is far too difficult.
-Ross.
