[sc34wg3] Comments on N884 (Dublin Core in TMs)

[Dipl.-Wirtsch.-Inf. Lutz Maicher]

I even think, that having standardized usage guidelines for the DC
vocabularies in Topic Maps will be very valuable. Below you will find my
comments to Lars Marius' thoughts. Additionally, I will send a second
email about my thoughts about interoperability.
> ---Datatypes
>
> Should we give concrete datatype URIs for the DC terms which have 
> datatypes, such as dc:type? I notice that DC does not actually commit 
> itself this far, but perhaps we should?
According to the latest DCMI Abstract Model recommendation (which I
refer now) [1] so called "syntax encoding scheme URIs" should be
assigned to "value strings" which are intended to be read by human
beings. I think, these encoding schemes are very similar to the property
[datatype] we have in variant or occurrence items (in TMDM). Some of
these encoding scheme URIs are proposed in the DC vocabulary
specification [2].

I have published the DCMT-topic map which represents all terms
standardized by the DCMI [3], [4]. This topic map does discloses all
labels, dependencies, etc. for each term. (The topic map is not
completely compliant to the current version of the standardization of
the usage of the DC vocabularies, some refinements will be necessary
when we have a stable version.) The purpose of this topic map to free
all topic maps authors from the burden to represent any of these
information in a topic map which only wants to represent some metadata.
The authors only have to use the right PSIs for the terms. And whenever
more information, like labels, etc. for the terms are necessary, this
topic map can be merged in or requested using TMRAP or TMIP (once the
DCMT-topic map has a TMRAP/TMIP interface). Generally, this topic map
should also disclose commonly used syntax encoding schemes.

> ---Subtyping
>
> In Dublin Core some of the terms are "refinements" of other terms. For 
> example, dc:abstract subtypes dc:description. Doesn't that mean that 
> we should also model this in the mapping by subtyping?
>
> I take the refinement to say that every abstract is also a 
> description. That matches the semantics of subtyping perfectly, as far 
> as I can tell.
>
> There is a discussion of some of the issues involved here:
>   http://www.garshol.priv.no/blog/115.html
In my opinion, all information about the "refinmentness" of a term are
in the scope of the DCMT-topic map. The authors only use the term, and
whenever any information about the relationship of the used term to
other terms are in interest, the DCMT-topic map can be requested.
> ---Specific mappings
>
> Is dc:type really the same as tmdm:type-instance?
No at all. I propose, to represent the "dc:type" property equally to all
other properties. One might argue, that a tmdm:type-instance
relationship can be added informative. This is discussed in more detail
in my DCAM<-->TMDM mapping paper I will introduce in my second email [5].
> Should dc:title really be represented using the default name type? I'm 
> asking because it seems reasonable to assume that the title is the 
> default name.
For this property the same argument holds. We should represent this
property equally to all other properties. And names can be added
informative as base name.
> --- The type vocabulary
>
> This reads like a list of topic types to me. Having looked through the 
> DB specs it seems like these are intended as the values for the 
> dc:type property. Should we make this more explicit? Should we state 
> something about how these are intended to be used? Of course, this 
> depends on how dc:type is mapped, but still...
Yeap. The type vocabulary should be used as value for the dc:type
property. As we will define "guidelines for the usage of DC vocabulary
in Topic Maps" we have to make it explicit how a value of a specific
property should be represented. This issue is even discussed in the paper.

Greetings from Leipzig
Lutz Maicher

[1] http://dublincore.org/documents/abstract-model/
[2] http://dublincore.org/documents/dcmi-terms/#H4
[3] http://www.informatik.uni-leipzig.de/~maicher/topicmaps/DCMT.ltm
[4] http://www.informatik.uni-leipzig.de/~maicher/community7.html
[5]
http://www.informatik.uni-leipzig.de/~maicher/publications/DCAMandTMDM_latest.pdf

-- 
______________________________________________

Dipl.-Wirtsch.-Inf. Lutz Maicher
Abteilung Automatische Sprachverarbeitung
Institut für Informatik | Universität Leipzig
Johannisgasse 26 | 04103 Leipzig

phone: 0049 - 341 - 97 - 32303
fax:   0049 - 341 - 97 - 32299
mail: maicher at informatik.uni-leipzig.de
http://www.informatik.uni-leipzig.de/~maicher/
http://www.informatik.uni-leipzig.de/~tmra/

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