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Re: Schema Mappings (was Re: AW: ANN: LOD Cloud - Statistics and compliance with best practices)

From: Antoine Zimmermann <antoine.zimmermann@insa-lyon.fr>
Date: Fri, 22 Oct 2010 19:06:48 +0200
Message-ID: <4CC1C4A8.7040205@insa-lyon.fr>
To: Leigh Dodds <leigh.dodds@talis.com>
CC: Linking Open Data <public-lod@w3.org>

Le 22/10/2010 17:23, Leigh Dodds a écrit :
> Hi,
> On 22 October 2010 09:35, Chris Bizer<chris@bizer.de>  wrote:
>>> Anja has pointed to a wealth of openly
>>> available numbers (no pun intended), that have not been discussed at all.
>> For
>>> example, only 7.5% of the data source provide a mapping of "proprietary
>>> vocabulary terms" to "other vocabulary terms". For anyone building
>>> applications to work with LOD, this is a real problem.
>> Yes, this is also the figure that scared me most.
> This might be low for a good reason: people may be creating
> proprietary terms because they don't feel well served by existing
> vocabularies and hence defining mappings (or even just reusing terms)
> may be difficult or even impossible.
> This also strikes me as an opportunity: someone could usefully build a
> service (perhaps built on facilities in Sindice) that aggregated
> schema information and provides tools for expressing simple mappings
> and equivalencies. It could fill a dual role: recommend more
> common/preferred terms, whilst simultaneously providing
> machine-readable equivalencies.

This sounds very much like what an ontology alignment server is doing: 
it provides alignments [often synonym with mappings] on demand (given 
two ontology URIs), either by retrieving locally stored alignments, or 
by asking another alignment server for an alignment that it may have, or 
by computing the alignment on the fly, given a certain direct matching 
algorithm or from the aggregation (e.g., composition) of existing 
alignments. The alignment server can also be used for various other 
things such as comparing alignments, evaluating them, rating them, 
updating them, etc.

A paper describing the Alignment server [1] has been submitted to the 
Semantic Web Journal and is under open review (you can read the paper 
and the reviews and submit your own reviews or comments). The server 
itself can be downloaded and installed anywhere [2].

> I know that Uberblic provides some mapping tools in this area,
> allowing for the creation of a more normalized view across the web,
> but not sure how much of that is resurfaced.

There are literally dozens of systems for ontology matching or schema 
mappings, which can more or less be used for Web Ontologies. Every year, 
a competition is organised [3] to evaluate the ontology matching tools, 
which features various tests among which several OWL ontology matching 
tasks. The output is a ranked list of equivalences or subsumption 
relations between the terms of the input ontologies. These tools are 
often unknown to the LOD enthusiasts although they could be obtained 
from their authors and tested on concrete cases. On the other side, the 
Ontology Matching crowd is always eager to find concrete applications to 
test their tools on real life problems. More information and some 500+ 
publications on the topic can be found on the ontologymatching.org [4]. 
Recall that ontology matching has its root in schema matching, which 
is---as Enrico Motta just said on this list---a 30 year old topic.

[1] Jérôme Euzenat and Chan Le Duc. The Alignment server: storing and 
sharing alignments on the semantic web. 
[2] Alignment API and Alignment Server. http://alignapi.gforge.inria.fr/
[3] The Ontology Alignment Evaluation Initiative (AOEI). 
[4] http://www.ontologymatching.org/

Antoine Zimmermann
Researcher at:
Laboratoire d'InfoRmatique en Image et Systèmes d'information
Database Group
7 Avenue Jean Capelle
69621 Villeurbanne Cedex
Lecturer at:
Institut National des Sciences Appliquées de Lyon
20 Avenue Albert Einstein
69621 Villeurbanne Cedex
Received on Monday, 25 October 2010 22:20:15 UTC

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