inkdroid

I’m just in the process of getting my head around SPARQL a bit more. At $work, Clay and I ran up against a situation where we wanted a query that would return a subgraph from an entire SKOS concept scheme for any assertions involving a particular concept URI as the subject. Easy enough right?

  DESCRIBE <http://lcsh.info/sh96010624#concept>

The thing is, for human readable displays we don’t want to display the URIs for related concepts (skos:broader, skos:narrower or skos:related) … we want to display the nice skos:prefLabel for them. Something akin to:

So how can we get a subgraph for a concept as well as any concept that might be directly related to it, in a single query? We came up with the following but I’d be interested in more elegant solutions:

PREFIX skos: <http://www.w3.org/2004/02/skos/core#>

CONSTRUCT {<http://lcsh.info/sh96010624#concept> ?p1 ?o1. ?s2 ?p2 ?o2}
WHERE
{
    {<http://lcsh.info/sh96010624#concept> ?p1 ?o1.}
    UNION
    {
        {<http://lcsh.info/sh96010624#concept> skos:narrower ?s2.}
        {?s2 ?p2 ?o2.}
    }
    UNION
    {
        {<http://lcsh.info/sh96010624#concept> skos:broader ?s2.}
        {?s2 ?p2 ?o2.}
    }
    UNION
    {
        {<http://lcsh.info/sh96010624#concept> skos:related ?s2.}
        {?s2 ?p2 ?o2.}
    }
}

The above ran quite nicely in my Arc playground. Any suggestions or ideas on how to boil this down would be appreciated. I also wanted to jot this query in the likely event that I forget how I did it.

Alistair wanted to have some data to demonstrate the potential of linked library data, so I quickly converted 10K MARC records (using a slightly modified version of MARC21slim2RDFDC.xsl and rewrote the subjects as lcsh.info URIs using a few lines of python…all a bit hackish, but it got this particular job done quickly.

The rewriting of subjects is basically a transformation of:

<http://lccn.loc.gov/00009010#manifestation>
  dc:creator "Rollo, David.";
  dc:date "c2000." ;
  dc:description "Includes bibliographical references (p. 173-223) and index." ;
  dc:identifier
     "URN:ISBN:0816635463 (alk. paper)",
     "URN:ISBN:0816635471 (pbk. : alk. paper)",
     "http://www.loc.gov/catdir/toc/fy032/00009010.html" ;
  dc:language "eng" ;
  dc:publisher "Minneapolis : University of Minnesota Press," ;
  dc:subject
    "Anglo-Norman literature",
    "Benoi?t, de Sainte-More, 12th cent.",
    "Latin prose literature, Medieval and modern",
    "Literacy",
    "Literature and history",
    "Magic in literature." ;
  dc:title "Glamorous sorcery : magic and literacy in the High Middle Ages /" ;
  dc:type "text" .

to:

<http://lccn.loc.gov/00009010#manifestation>
    dc:creator "Rollo, David." ;
    dc:date "c2000." ;
    dc:description "Includes bibliographical references (p. 173-223) and
index." ;
    dc:identifier "URN:ISBN:0816635463 (alk. paper)", "URN:ISBN:0816635471 (pbk. : alk. paper)", "http://www.loc.gov/catdir/toc/fy032/00009010.html" ;
    dc:language "eng" ;
    dc:publisher "Minneapolis : University of Minnesota Press," ;
    dc:subject <http://lcsh.info/sh85005082#concept>,
      <http://lcsh.info/sh85077482#concept>,
      <http://lcsh.info/sh85077565#concept>,
      <http://lcsh.info/sh85079624#concept>,
      <http://lcsh.info/sh86008161#concept>,
      "Benoi?t, de Sainte-More, 12th cent." ;
    dc:title "Glamorous sorcery : magic and literacy in the High Middle Ages
/" ;
    dc:type "text" .

Clearly there are lots of ways to improve even this simplified description: URIs for entries in the Name Authority File, referencing identifiers as resources rather than string literals (an artifact of the XSLT transform), removing ISBD punctuation, unicode normalization (&cough;), etc.

You may notice I kind of fudged the URI for the book itself using the LCCN service at LC: http://lccn.loc.gov/00009010#manifestation (which does resolve, but doesn’t serve up RDF yet). I’m no FRBR expert so I’m not sure if the use of “manifestation” in this hash URI makes sense. I just wanted to distinguish between the URI for the description, and the URI for the thing being described. I think it’s high time for me to understand FRBR a lot more.

If you prefer diagrams to turtle here is a graph visualization from the w3c rdf validator for the record.

If you happen to be in the DC area on May 8th and are interested in linked data and the practical application of semantic web technologies like RDF and OWL please join us at the Library of Congress for a presentation by Alistair Miles, key developer of SKOS, and semantic web practitioner at the University of Oxford.

Below is the announcement, I hope you can make it. Oh, and if you are really interested in this stuff we’re having some brown bag sessions later in the afternoon that you are welcome to attend, just email me at ehs [at] pobox [dot] com.

The Simple Knowledge Organization System (SKOS), in the Context of Semantic Web Deployment, Alistair Miles, University of Oxford May 8th 10am – 6th 11:30am, 2008, Montepelier Room, Madison Building, Library of Congress (map) .

Links are valuable. Links between documents, between people, between ideas, between data. Data is now a first class Web citizen, and the Web is expanding as more of these valuable networks are deployed within its fabric. Well-established knowledge organization systems like the Library of Congress Subject Headings will play a major role within these networks, as hubs, connecting people with information and providing a firm foundation for network growth as many new routes to the discovery of information emerge through the collective action of individuals. Or will they?

This talk introduces the Simple Knowledge Organization System (SKOS), a soon-to-be-completed W3C standard for publishing thesauri, classification schemes and subject headings as linked data in the Web. This talk also presents SKOS in the context of the W3C’s Semantic Web Activity, and in particular the work of the W3C’s Semantic Web Deployment Working Group where other specifications are being developed for publishing linked data in the Web, for embedding linked data in Web pages, and for managing Semantic Web vocabularies. Finally, this talk takes a mildly inquisitive look at the value propositions for linked data in the Web, and how LCSH might be deployed in the Web for better information discovery.

Alistair’s background is in the development of Web technologies for scientific applications. He was a research associate in the e-Science department of the Rutherford Appleton Laboratory, where he was introduced to Semantic Web technologies and first developed SKOS. He has recently moved to the University of Oxford to work on linking fruit fly genomics research data, and he hopes everything he knows about the Semantic Web will turn out to be useful after all.

Recently there was a bit of interesting news around a MARBI Discussion Paper 2008-DP04 regarding semweb technologies at LC.

Related to this work are RDF/OWL representations and models for MODS and MARC, which we are also developing. Several representations of MODS in RDF/OWL, such as the one from the SIMILE project, have been made available as part of various projects and we have found they useful for our analysis and to inform our design process. We want to bring them together into one easily downloaded and maintained RDF/OWL file for use in community experimentation with RDF applications. Our time line is to have the MODS RDF ready for community comment by June.