- From: Miles, AJ \(Alistair\) <A.J.Miles@rl.ac.uk>
- Date: Wed, 30 Mar 2005 18:55:05 +0100
- To: "Mark van Assem" <mark@cs.vu.nl>, <public-esw-thes@w3.org>
Hi Mark, all, I've put a new editor's draft of the 'Quick Guide ...' at: http://www.w3.org/2004/03/thes-tf/primer/2005-03-30 ... incorporating your suggestions below. How does this look? Some notes on what I changed ... > I have some general comments and some more detailed suggestions. > > In general I'm still wondering about the intended > audience/goals of the > Quick Guide [1]. What I roughly understood is that it's > something along > the lines of: > > (a) the audience consist of (among others) thesaurus owners > who know the > basics of RDF and are (1) interested if converting to RDF > gives benefits > and (2) want simple examples of how things should work > > (b) the outcome should be that the thesaurus owners have an intuitive > feeling of (1) how an RDF version would look like and (2) where to get > more info on how to do conversion in more detail. > > If that's the case, I think this version satisfies a2 and b1, but some > more material is needed for b2. For example, it would probably be > helpful for them to know what technology one can use to convert an XML > version of a thesaurus to an RDF version (e.g. XSLT). Is a separate > section on "Conversion" something to consider? Or a reference > to another > (to be created) document? Conversion is a tricky subject, because as the discussion went before it isn't a matter of simply saving in SKOS format - a commitment must be made to the good use of URIs etc. Also the specifics of generating and maintaining a SKOS/RDF representation of a thesaurus vary wildly depending on the technologies in place in the organisation, which makes a general sort of note difficult to write. So I left this for the moment ... maybe we can discuss whether to try covering conversion in another note? > > The first part of the section "Expressing a Thesaurus in RDF" is the > crucial bit in which readers will have to experience the > "aha!" effect. > The extract from the UKAT, the following graph and its XML > serialisation > are definately the way for doing that trick. There are > some points that might obstruct it (see below), but I'm not really in > the position to evaluate if they are important or not as I'm > not in the > target audience :-) > > 1) the relation between "terms" and "skos:concepts". > 2) the relation between a "tree-form" (UKAT extract) and a > "graph-form" > of a thesaurus > 3) the relation between the graph and its serialization > > Concerning (1) I think this can be explicated by explaining that ISO > thesauri like UKAT are term-centric, but SKOS is concept-centric. What > this probably boils down to from the reader's perspective is that a > term's preferred term is mapped to skos:prefLabel, its non-preferred > terms to skos:altLabel, and that for each pref-term a separate > skos:Concept is introduced with a unique identifier (URI). Added the text: 'Note that, in expressing the content of a thesaurus such as the UKAT in RDF using SKOS Core, each descriptor (preferred term) becomes a preferred label for a concept, and each non-descriptor (non-preferred term) becomes an alternative label for a concept.' > > Concerning (2), I don't know if this is really an issue, as we should > presuppose that the audience knows the basics of RDF. Left that. > > Concerning (3), it's important to note that the serialization shown is > not an _exact_ serialization of the graph above it. The > XML/RDF defines > one concept and points at e.g. 'economic policy', while the graph also > shows the concept 'economic policy' and its skos:prefLabel. One more > thing is that the RDF/XML has a skos:inScheme property, which is not > present in the graph. Maybe this can be excluded to keep > things simple? I wanted to leave the skos:inScheme statement in, because I think it's quite important. But I changed the text above the RDF/XML box to: 'An RDF/XML serialisation of the RDF description of the 'Economic cooperation' concept from the UKAT is below:' > > Some detailed comments: > > The abstract mentions "how to express the content and structure of a > thesaurus". Maybe we can add e.g. "and thesaurus-like resources" that > SKOS is useful for more than thesauri? Or is "thesaurus-like" > a tricky > formulation. Added to intro: 'SKOS Core is designed to be used with not only thesauri, but also other types of 'concept scheme', such as classification schemes, subject heading systems, controlled vocabularies, glossaries, taxonomies etc' > > The abstract (and a later section) also mentions "RDF allows > your data > to be linked to and/or merged with other RDF data ..." Will > it be clear > enough for people from other communities what is meant with > linking and > merging? Maybe the point here is that RDF allows for easier use of > different sources in conjunction over the web. Added to intro: '... In practice, this means that data sources can be distributed across the web in a decentralised way, but still be meaningfully composed and integrated by applications, often in novel and unanticipated ways.' > > A similar point concerning "serialisation of the graph" in the > Introduction. I liked the way you explained this in the Guide > ("An RDF > graph can be serialised (i.e. encoded as a series of > characters) ... "). > Maybe include that bit here? Done. > > In section "Expressing Thesaurus Metadata in RDF" I think > it's very good > that the text emphasises URIs. Maybe also put the term "unique > identifier" in there to get bells ringing with those who are > unfamiliar > with URIs? Added: 'URIs are globally unique identifiers that may be used to refer to a resource unambiguously from any context. Anything can be a 'resource', not just web documents, therefore URIs can be used as identifiers for anything.' > > About the explanation of skos:hasConcept in the next section, it may > also ring more bells if "facet" is mentioned in conjunction > with "field"). Left that, because 'facet' is difficult due to overloaded usage. > > In the section "Publishing RDF Data" a sentence might be > included on why > it's useful to put the RDF thesaurus in an RDF server, e.g. something > like "This allows anyone to query the thesaurus over the web using an > RDF query language." (and some more refs to good material for > people to > get started with this?) Added: 'Publishing via an RDF server allows anyone to query the thesaurus over the web via an RDF query language such as SPARQL [SPARQL].' Cheers, Al.
Received on Wednesday, 30 March 2005 17:55:07 UTC