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

Great discussion.

> So I suppose the question to settle is just what is a TemporalEntity 
> as distinct from a Duration or a TimePosition?
>

As a starter, a TemporalEntity may have an unknown duration or time 
position.  It can also have multiple durations which is something that I 
often see in the digital humanities domain where it is used to model 
uncertainty,  e.g., to distinguish an earliest start and end from a most 
likely start and end.


Best,
Krzysztof



On 12/28/2016 02:19 PM, Joshua Lieberman wrote:
> Whether  TemporalEntity has subclasses is not necessarily a problem. 
> GF_FeatureType also has subclasses. But the spatial extent of a 
> GF_Feature is unquantifiable without a model property such as a 
> Geometry. It seems the temporal extent of a TemporalEntity also is 
> unquantifiable without a property such as a Duration or TimePosition. 
> So I suppose the question to settle is just what is a TemporalEntity 
> as distinct from a Duration or a TimePosition?
>
> Josh
>
>> On Dec 28, 2016, at 11:01 PM, simon.cox@csiro.au 
>> <mailto:simon.cox@csiro.au> wrote:
>>
>> The class :TemporalEntity is already in the ontology. It has 
>> subclasses :Instant and :Interval. Which looks comparable to Geometry 
>> as superclass of Point, Line, Polygon etc at first glance at least. 
>> Which would make it _not_ a feature. Which is why I raised the issue.
>>
>> Simon
>>
>> ------------------------------------------------------------------------
>> *From:* Krzysztof Janowicz <janowicz@ucsb.edu <mailto:janowicz@ucsb.edu>>
>> *Sent:* Wednesday, 28 December 2016 9:08:33 PM
>> *To:* Joshua Lieberman; Cox, Simon (L&W, Clayton)
>> *Cc:* public-sdw-wg@w3.org <mailto:public-sdw-wg@w3.org>
>> *Subject:* Re: OWL-Time - ISSUE-65: General purpose temporal predicates
>> I like Josh's argumentation and agree on the separation of a temporal 
>> entity from the time model the same way we deal with spatial entities 
>> and geometries. This would also enable us to easily support multiple 
>> temporal granularities the same way we can have multiple geometries 
>> per feature.
>>
>>
>> On 12/28/2016 01:03 PM, Joshua Lieberman wrote:
>>> Doesn’t that depend on what a Temporal Entity “is”. The ISO - OGC 
>>> feature-geometry disjunction is based on Geometry being a model 
>>> property for a Feature (Spatial Thing), not the Feature itself. It 
>>> seems to me that this could have a parallel in OWL-Time, with 
>>> Temporal Entity being the thing with an extent in time, and Duration 
>>> or TimePosition being a model property for that Entity. If that 
>>> parallel is valid, then it wouldn’t be inconsistent to say that a 
>>> Feature is-also-a Temporal Entity if it has a Duration or 
>>> TimePosition model property.
>>>
>>> Josh
>>>
>>>> On Dec 28, 2016, at 8:16 PM, 
>>>> <mailto:simon.cox@csiro.au>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 _/nt/_ 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
>>>> CSIRO Land and Water <http://www.csiro.au/Research/LWF>
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>>>> researchgate.net/profile/Simon_Cox3 
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>>>
>>
>>
>> -- 
>> Krzysztof Janowicz
>>
>> Geography Department, University of California, Santa Barbara
>> 4830 Ellison Hall, Santa Barbara, CA 93106-4060
>>
>> Email:jano@geog.ucsb.edu
>> Webpage:http://geog.ucsb.edu/~jano/
>> Semantic Web Journal:http://www.semantic-web-journal.net
>


-- 
Krzysztof Janowicz

Geography Department, University of California, Santa Barbara
4830 Ellison Hall, Santa Barbara, CA 93106-4060

Email: jano@geog.ucsb.edu
Webpage: http://geog.ucsb.edu/~jano/
Semantic Web Journal: http://www.semantic-web-journal.net