François Scharffe wrote:
Kingsley Idehen wrote:
François Scharffe wrote:
Hugh Glaser wrote:
Hi,
To put it in simple terms for me :-)
Are you after the algorithms we use to identify when two instances
are the same?
Best
Hugh
Yes !
François
So if the answer is "Yes". Then do you mean things in the ABox and
TBox? Must be clear here as being too generic leads to confusion.
Link generators are working at the instance level (ABox), they
generate links between instances. They need some input, a
specification of what should be interlinked. We think this
specification can be lifted to an alignment between vocabularies
(TBoxes). Well we are not 100% sure this will work, that's why we
would like to get such tools and their linkage specifications.
I can take an example, interlinking persons: one dataset is described
with FOAF, the other with VCard.
?x foaf:name ?name.
?y vc:n [
vc:family-name ?fn;
vc:given-name ?gn.
].
the linkage specification might be something like:
if compare(?name, concat(?gn," ",?fn)) > threshold
then output("?x owl:sameAs ?y")
Fine, that's an instance data (ABox) oriented equivalence algorithm.
In fact, this specification says
foaf:name <-> concat(vc:given-name," ",vc:family-name)
which is an alignment at the TBox level that can be lifted from the
linkage specification.
In the TBox you would be the properties are either equivalent or one
property is a sub property of the other. Once done, reasoners can then
navigate the instance data via the TBox mappings. This is basically a
major aspect of the UMBEL project. Even in its current form, if you
taking the alignment rules (expressed in OWL) you have a pretty rich
bases for leveraging linkages across many shared ontologies. To extend,
you simply find you slot, and map to that. which is back to the:
embraces and extend principle.
Anyway, your response provides clarity, including the fact that the end
product of this effort isn't a solely about a bag of ABox oriented
"owl:sameAs" links :-)
As I've stated before, coherent Linked Data magic happens, when we
exploit the power of TBox level mapping across disparate ontologies.
"Deceptively Simple" always trumps "Simply Simple" over the long haul,
the latter simply doesn't scale :-)
Kingsley
I hope I was clear enough this time ;)
Cheers,
François
sameAs is not the best way to align things in the TBox.
Kingsley
On 11/06/2009 12:57, "François Scharffe"
<[email protected]> wrote:
Dear LODers,
There has been a couple of discussions already on this list on the
need
for a vocabulary to represent correspondences between terms of
different
vocabularies. We also saw recently various tools (e.g. Silk,
ODDlinker)
allowing to automatically interlink datasets given a specification of
what should be linked.
However, there is currently no common way to publish and share this
information (i.e., not the links but the way to generate them, see [1]
for precision).
We are setting up an experiment [1] to see if it is possible to
provide
useful services from this data. But for that purpose we need your
help.
So this is a call for contribution: we are collecting any
specification
of link generator for the LOD graph.
Of course, do not hesitate to comment on the idea or to tell us if you
want to be involved.
We promise a report on this by the end of summer (northern
hemisphere :).
Cheers,
François
[1] http://melinda.inrialpes.fr
--
Regards,
Kingsley Idehen Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO
OpenLink Software Web: http://www.openlinksw.com
