Paul A Houle wrote:
I think there are a few scenarios here.
In my mind, dbpedia.org <http://dbpedia.org> is a site for
tripleheads. I use it all the time when I'm trying to understand how
my systems interact with data from dbpedia -- for that purpose, it's
useful to see a reasonably formatted list of triples associated with
an item. A view that's isomorphic to the triples is useful for me there.
Yes, better interfaces for browsing dbpedia/wikipedia ought to be
built -- navigation along axes of type, time, and space would be
obviously interesting, but making a usable interface for this
involves some challenges which are outside the scope of dbpedia.org
<http://dbpedia.org>; The point of linked data is anybody who wants
to make a better browsing interface for dbpedia.
Another scenario is a site that's ~primarily~ a site for humans and
secondly a site for tripleheads and machines, for instance,
That particular site is built on an object-relational system which
has some (internal) RDF features. The site was created by merging
dbpedia, freebase and other information sources, so it exports
linked data that links dbpedia concepts to images with very high
precision. The primary vocabulary is SIOC, and the RDF content for a
page is ~nearly~ isomorphic to the content of the main part of the
page (excluding the sidebar.)
However, there is content that's currently exclusive to the human
interface: for instance, the UI is highly visual: for every
automobile make and model, there are heuristics that try to pick a
"better than average" image at being both striking and representative
of the brand. This selection is materialized in the database.
There's information designed to give humans an "information scent" to
help them navigate, a concept which isn't so well-defined for
webcrawlers. Then there's the sidebar, which has several purposes,
one of them being a navigational system for humans, that just isn't
so relevant for machines.
There really are two scenarios I see for linked data users relative
to this system at the moment: (i) a webcrawler crawls the whole
site, or (ii) I provide a service that, given a linked data URL,
returns information about what ontology2 knows about the URL. For
instance, this could be used by a system that's looking for
multimedia connected with anything in dbpedia or freebase. Perhaps I
should be offering an NT dump of the whole site, but I've got no
interest in offering a SPARQL endpoint.
As for friendly interfaces, I'd say take a look analytically at a
What's going on here? This is being done on a SQL-derivative
system that has a query builder, but you could do the same thing w/
SPARQL. We'd image that there are some predicates like
starting with a URL that represents a make of car (a nameplate,
like Chevrolet) we'd then traverse the hasCarModel relationship to
enumerate the models, and then do a COUNT(*) of hasPhotograph
relationships for the cars to create a count of pictures for each
model. Generically, the construction of a page like this involves
doing "joins" and traversing the graph to show, not just the triples
that are linked to a named entity, but information that can be found
by traversing a graph.
People shouldn't be shy about introducing their own predicates; the
very nature of inference in RDF points to "creating a new predicate"
as the basic solution to most problems. In this case,
hasPreferredThumb is a perfectly good way to materialize the result of
a complex heuristic.
(One reason I'm sour about public SPARQL endpoints is that I don't
want to damage my brand by encouraging amnesic mashups of my content;
a quality site really needs a copy of it's own data so it can make
additions, corrections, etc; one major shortcoming of Web 2.0 has
been self-serving API TOS that forbid systems from keeping a memory --
for instance, Ebay doesn't let you make a price tracker or a system
that keeps dossiers on sellers. Del.icio.us <http://Del.icio.us>
makes it easy to put data in, but you can't get anything interesting
out. Web 3.0 has to make a clean break from this.)
Database-backed sites traditionally do this with a mixture of
declarative SQL code and procedural code to create a view... It would
be interesting to see RDF systems where the graph traversal is
specified and transformed into a website declaritively.
A summary for the ages.
This is basically an aspect of the whole Linked Data meme that is lost
on too many.
Thank you very much!!
Kingsley Idehen Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO
OpenLink Software Web: http://www.openlinksw.com