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Re: OWL-Time - ISSUE-65: General purpose temporal predicates

From: Andrea Perego <andrea.perego@jrc.ec.europa.eu>
Date: Wed, 25 Jan 2017 22:43:07 +0100
To: Simon.Cox@csiro.au
Cc: public-sdw-wg@w3.org
Message-id: <c44d4f29-022b-9a40-9909-fb7486ae8347@jrc.ec.europa.eu>
Hi, Simon.

Not sure this issue was sorted out, but I would like to raise a question 
more related to the use of time periods in metadata.

The typical case is the temporal coverage of a dataset. Following DCAT, 
this is done by using dct:temporal + dct:PeriodOfTime. However, in DCAT 
no specific properties are recommended for start / end date(time). This 
has been addressed in ADMS, by using schema:startDate and 
schema:endDate, respectively. And this solution has also been adopted in 
DCAT-AP.

I've checked the Time Ontology, but I'm not completely sure which are 
the properties that can be used for this purpose (time:hasBeginning? 
time:hasEnd?). Also, I wonder whether / how dct:PeriodOfTime matches in 
the Time Ontology model (time:TemporalEntity? time:Interval?).

In general, I think it would be good to have an explicit example on how 
to use the Time Ontology in metadata, where we also have issues like, 
e.g., specifying "open" intervals (i.e., with just a start / end date) 
and using "nominal periods" (e.g., geological / archeological eras).

Thanks!

Andrea


On 28/12/2016 20:16, Simon.Cox@csiro.au wrote:
> The primary goal of OWL-Time is to implement Allen’s temporal relations
> in OWL, so all the OWL-Time predicates have Temporal classes as both
> domain and range. For example, ‘hasBeginning’ relates a temporal entity
> to a temporal instant. This means that attaching timing information to
> any event or activity using one of these predicates implies that it
> _/is/_ a “Temporal Entity”. This would be inconsistent with the approach
> used in the OGC/ISO Feature Model for associating geometry with a
> feature, in which feature types are _/not/_ subclassed from geometries,
> but have associations with geometries. At least that would be the
> argument if time is treated the same as geometry.
>
>
>
> As there appears to be interest in standard predicates to associate
> timing information to events or activities, we have a problem. One
> solution (ISSUE-64) would be to relax the global domain constraints on
> the existing predicates. Alternatively, we can create some general
> purpose object properties, such as the following:
>
>
>
> :activityBeginning
>
>   rdfs:comment "Beginning of an event or activity."@en ;
>
>   rdfs:range :Instant ;
>
> .
>
> :activityDuration
>
>   rdfs:comment "Duration of an event or activity, expressed as a scaled
> value"@en ;
>
>   rdfs:range :Duration ;
>
> .
>
> :activityDurationDescription
>
>   rdfs:comment "Duration of an event or activity, expressed using a
> structured description"@en ;
>
>   rdfs:range :GeneralDurationDescription ;
>
> .
>
> :activityEnd
>
>   rdfs:comment "End of an event or activity."@en ;
>
>   rdfs:range :Instant ;
>
> .
>
> :activityTime
>
>   rdfs:comment "Supports the assignment of a temporal entity (instant or
> interval) with an event or activity"@en ;
>
>  rdfs:range :TemporalEntity ;
>
> .
>
>
>
> The slightly awkward names are because hasBeginning, hasDuration etc are
> already in use.
>
> Not at all wedded to activity*. Could be event* or something else if
> anyone has any smart ideas.
>
>
>
> I’ve added these to the branch here:
>
> https://github.com/w3c/sdw/blob/simon-time-predicates/time/rdf/time.ttl
>
>
>
> OTOH, some upper-level ontologies make a fundamental distinction between
> time-bounded entities (occurrent or perdurant) and non-time-bounded
> entities (continuant or endurant). If we accept this viewpoint, then we
> might just use the original OWL-Time predicates and accept the
> entailment.  I guess it depends which fundamental commitment we are
> willing to make.
>
>
>
> Simon
>
>
>
> *Simon J D Cox *
>
> Research Scientist
>
> Environmental Informatics
>
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>
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>
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>
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>
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-- 
Andrea Perego, Ph.D.
Scientific / Technical Project Officer
European Commission DG JRC
Directorate B - Growth and Innovation
Unit B6 - Digital Economy
Via E. Fermi, 2749 - TP 262
21027 Ispra VA, Italy

https://ec.europa.eu/jrc/

----
The views expressed are purely those of the writer and may
not in any circumstances be regarded as stating an official
position of the European Commission.
Received on Wednesday, 25 January 2017 21:44:09 UTC

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