Re: [ontology-summit] Ontology driven Data Integration using owl:equival

[Gary Berg-Cross <gbergcross@xxxxxxxxx>]

Pat et al,

I agree with what pat wrote on this and note that there has been a sort of parallel discussion of

some of this under the mail thread of "

OWl and Knowledge reuse via import and modularizat

ion

As part of this Leo created some integrating ontology examples (not on Organization) - 

ntegration-a-b-ontology-imports.png shows the imports.

Ontology-a-classes.png shows the classes of ontology-a.owl.

Ontology-b-classes.png shows the classes of ontology-b.owl.

Classes-equivalences-integration-a-b-ontology.png shows the classes and equivalences of integration-a-b.owl.

see http://ontolog.cim3.net/forum/ontology-summit/2014-02/msg00122.html for that message and attached files.

I responded in a fashion similar to Pat's point on different instances:

>Leo

Thank you for advancing the conversation.  Concrete, illustrative examples can help focus the discussion. And you've shown how to do it if the concepts are equivalent or thought so.

In your examples things are a bit simple and would be a bit more difficult, I think, with ontologies that were generated without considering what had been done in a domain.  So for example equating/equivalence between A and B ontologies seems directly possible, but if one of them was a bit more precise and detailed and said that PLACE hasA LOCATION then we might not equate PLACE in A with LOCATION  in B. 

We'd know more about what is meant by the 2 concepts if we looked at the data instances they represent and found >that in A we have place locations like Grand Canyon  and in B they are lat-lon. 

Gary Berg-Cross, Ph.D.  

gbergcross@xxxxxxxxx     

http://ontolog.cim3.net/cgi-bin/wiki.pl?GaryBergCross

NSF INTEROP Project  

http://www.nsf.gov/awardsearch/showAward.do?AwardNumber=0955816    

Potomac, MD

240-426-0770

On Fri, Feb 7, 2014 at 3:53 PM, Patrick Cassidy <pat@xxxxxxxxx> wrote:

There is a serious problem with the suggested methodology:

 

>  Two ontologies or vocabularies (for instance FOAF and Schema.org) include definitions for the same class (or kind) of entity e.g., an Organization,

>  and as a consequence we end up with Web accessible   documents comprised of RDF statements that describe Organizations as instances of  foaf:Organization or schemaorg:Organization.
>
>  Challenge: How do we get a merged view of all the organizations, irrespective of how they've been described across various RDF documents?
>
>  Solution:
>
>  1. Make a mapping/bridge/meta ontology that uses owl:equivalentClass relations to indicate the fact

>  that <http://xmlns.com/foaf/0.1/Organization> and <http://schema.org/Organization> are equivalent.
>
>  2. Load the mapping/bridge/meta ontology document into a data management system that's capable

>  of applying reasoning and inference to the equivalence claim based on its comprehension of the relation semantics expressed
>
>  3. Access instances of the <http://xmlns.com/foaf/0.1/Organization> classes (e.g., by seeking a description

>   of <http://xmlns.com/foaf/0.1/Organization> which should produce a solution that includes subjects

>  of instanceOf (rdf:type) relations) -- and this will show a union of all instances of across <http://xmlns.com/foaf/0.1/Organization> and <http://schema.org/Organization>
>
>  4. Reverse the action in step 4 above -- the results should be the same.

   If you create an equivalence mapping between entities in  independently developed ontologies  and try to “reason” with it in any but the most highly restricted manner, you will almost certainly find unintended inferences, likely logical inconsistency, and potentially a great deal of gibberish.    When you look at the logical specifications of entities of the same name in different ontologies, they are often quite different, even though the intuition for the meanings may be similar.  For “organization”, for example, some ontologies have that as a subtype of “group of people”.  In some legal jurisdictions, an Organization can exist without any members – i.e., no people.   That can lead to logical contradictions if different definitions are equated.  I have never seen “process” defined the same way in any two independent ontologies.

 

   If one only wants to create equivalencies and use that to perform probabilistic or pattern-matching reasoning, that may lead to useful results that can be helpful for the humans who evaluate the results.  But don’t expect the kind of accuracy that would be needed to allow the computers to make mission-critical decisions without human intervention.   Or, if one only wants to extract some one or two properties of an entity (e.g. the director of a film), equating “film” in two different ontologies may work as intended.   But extreme caution is advised.

 

     Pat

 

Patrick Cassidy

MICRA Inc.

cassidy@xxxxxxxxx

1-908-561-3416

 

From: ontology-summit-bounces@xxxxxxxxxxxxxxxx [mailto:ontology-summit-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Andrea Westerinen
Sent: Friday, February 07, 2014 1:17 PM
To: Ontology Summit 2014 discussion
Subject: Re: [ontology-summit] Ontology driven Data Integration using owl:equivalentClass relations

 

Kingsley, +1 ... Your mapping/bridge/meta ontology is my "integrating ontology".  And, you captured the essence extremely well in your demos.

 

The keys are: 

1.  Creating the mappings

2.  Reasoning with the mappings

 

Clearly this works over data that is Linked Data or data in ontologies.

 

 

-- 

Andrea Westerinen

T: 425.891.8407

arwesterinen@xxxxxxxxx or andreaw@xxxxxxxxxxx

http://ontolog.cim3.net/cgi-bin/wiki.pl?AndreaWesterinen

organizingknowledge.blogspot.com

 

On Fri, Feb 7, 2014 at 10:01 AM, Kingsley Idehen <kidehen@xxxxxxxxxxxxxx> wrote:

All,

Starting a new thread based on the theme above to make what I am trying to demonstrate clearer.

Situation:

Schema.org [1] is a collaborative effort aimed as simplifying structured data publication to the Web. As part of this effort, a number of collaborators have collectively produced a number of shared vocabularies under the "schema.org" namespace.

In addition to what's being produced by Schema.org there are a thousands of shared ontologies and vocabularies that have been constructed and published to the Web from a plethora of sources, many of these have been aggregated by services such as LOV (Linked Open Vocabulary) [2] which is basically accentuates the TBox and RBox aspects of the Linked Open Data (LOD) Cloud.

Typical Integration Problem:

Two ontologies or vocabularies (for instance FOAF and Schema.org) include definitions for the same class (or kind) of entity e.g., an Organization, and as a consequence we end up with Web accessible documents comprised of RDF statements that describe Organizations as instances of  foaf:Organization or schemaorg:Organization.

Challenge: How do we get a merged view of all the organizations, irrespective of how they've been described across various RDF documents?


Solution:

1. Make a mapping/bridge/meta ontology that uses owl:equivalentClass relations to indicate the fact that <http://xmlns.com/foaf/0.1/Organization> and <http://schema.org/Organization> are equivalent.

2. Load the mapping/bridge/meta ontology document into a data management system that's capable of applying reasoning and inference to the equivalence claim based on its comprehension of the relation semantics expressed

3. Access instances of the <http://xmlns.com/foaf/0.1/Organization> classes (e.g., by seeking a description of <http://xmlns.com/foaf/0.1/Organization> which should produce a solution that includes subjects of instanceOf (rdf:type) relations) -- and this will show a union of all instances of across <http://xmlns.com/foaf/0.1/Organization> and <http://schema.org/Organization>

4. Reverse the action in step 4 above -- the results should be the same.


Live Demo Link:

[1] http://lod.openlinksw.com/describe/?url=""> -- description of <http://xmlns.com/foaf/0.1/Organization> *without inference and reasoning enabled*, so the relations presented are specific to the aforementioned class.

[2] http://lod.openlinksw.com/describe/?url=""> -- description of <http://schema.org/Organization> *without inference and reasoning enabled*, so the relations presented are specific ot the aforementioned class .

[3] http://lod.openlinksw.com/describe/?url=""> -- description of <http://xmlns.com/foaf/0.1/Organization> *with inference and reasoning enabled*.

[4] http://lod.openlinksw.com/describe/?url=""> -- description of <http://schema.org/Organization> with *inference and reasoning enabled*.

--

Regards,

Kingsley Idehen
Founder & CEO
OpenLink Software
Company Web: http://www.openlinksw.com
Personal Weblog: http://www.openlinksw.com/blog/~kidehen
Twitter Profile: https://twitter.com/kidehen
Google+ Profile: https://plus.google.com/+KingsleyIdehen/about
LinkedIn Profile: http://www.linkedin.com/in/kidehen







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