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Re: time ontology should allow "conference1 after conference2"

From: Feng Pan <pan@ISI.EDU>
Date: Thu, 2 Mar 2006 15:35:17 -0800 (PST)
To: Dan Connolly <connolly@w3.org>
cc: public-swbp-wg@w3.org, Jerry Hobbs <hobbs@ISI.EDU>
Message-ID: <Pine.GSO.4.60.0603021532500.6034@nitro.isi.edu>


Thank you very much for your comments.

In fact, in our note, we have pointed out that "In an extension of the
time ontology [5,7], we also allow temporal predicates to apply
directly to events, should the user wish, but here we restrict our
treatment to temporal entities."

With such extension you can represent directly :conference1
swbp-time:intBefore :conference2 after defining conference1 and
conference2 as events.

We're caught between two poles here -- You wanted this extension so we
put it in, and Chris Welty strongly objected to having it as part of
the main time ontology, so we made it an extension.

Yes, our basic temporal concepts are constrained to be
contiguous/convex, but in our work on temporal aggregates [1,2], we
have developed an ontology of temporal aggregates for OWL-Time, which
can be used to represent your example "a meeting goes from 9am to 5pm
Monday and Tuesday".  We can make this extension available as part of
the time ontology too, if you think that's important for the first


- Feng Pan and Jerry Hobbs

[1] Feng Pan and Jerry R. Hobbs. 2005. Temporal Aggregates in
OWL-Time. In Proceedings of the 18th International Florida Artificial
Intelligence Research Society Conference (FLAIRS-2005), Clearwater
Beach, Florida, pp. 560-565, AAAI Press,
2005. http://www.isi.edu/~pan/time/pub/pan-hobbs-FLAIRS05.pdf

[2] Feng Pan. 2005. A Temporal Aggregates Ontology in OWL for the
Semantic Web. In Proceedings of the AAAI Fall Symposium on Agents and
the Semantic Web, Arlington, Virginia, 2005.

On Tue, 21 Feb 2006, Dan Connolly wrote:

> I just found
> http://www.isi.edu/~pan/SWBP/time-ontology-note/time-ontology-note.html
> via WG minutes and such.
> :TemporalEntity
>      a       owl:Class ;
>      rdfs:subClassOf :TemporalThing ;
>      owl:equivalentClass
>              [ a       owl:Class ;
>                owl:unionOf (:Instant :Interval)
>              ] .
> and the domain/range of intBefore is constrained to TemporalEntity.
> So I can't just say
>  :conference1 swbp-time:intBefore :conference2.
> without implying that :conference1 is an :Instant or :Interval.
> I have to have some property that relates a conference to
> a time interval, and then use :intBefore on that.
> I can't see any reason for the indirection.
> The cyc ontology seems to express all the relevant stuff
> without this constraint. The cyc after relationship
> applies to not only instants and intervals, but also
> conferences, meetings, people, etc.
> http://www.cyc.com/cycdoc/vocab/time-vocab.html#after
> The TemporalThing class is also not constrained to be
> contiguous/convex; if a meeting goes from 9am to 5pm
> Monday and Tuesday, it's still OK to call it a cyc:TemporalThing,
> even though it's got a hole.
> http://www.cyc.com/cycdoc/vocab/time-vocab.html#TemporalThing
> I'm not sure whether this in-progress draft is constrained
> to have convex temporal objects, but I was just reviewing SUMO
> the other day, and it _is_ constrained to convex intervals,
> and I can't see why.
> p.s. in turtle, rather than
>  owl:maxCardinality "1"^^xsd:nonNegativeInteger
> you can just write
>  owl:maxCardinality 1.
> --
> Dan Connolly, W3C http://www.w3.org/People/Connolly/
> D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E

Feng Pan, Ph.D. Candidate
USC Information Sciences Institute (ISI)
Email: pan@isi.edu
Web: http://www.isi.edu/~pan/
Received on Thursday, 2 March 2006 23:51:52 UTC

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