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Re: [OWL-S] Process subClassOf IntervalEvent

From: David Martin <martin@AI.SRI.COM>
Date: Mon, 03 May 2004 22:36:28 -0700
Message-ID: <40972BDC.400@ai.sri.com>
To: Feng Pan <pan@isi.edu>
Cc: Jerry Hobbs <hobbs@isi.edu>, public-sws-ig@w3.org

Feng Pan wrote:

> Hi David,
> 
> Thanks for copying the email to me. Yes, I'm on public-sws-ig@w3.org.
> 
> Currently the time ontology is used in Process.owl as follows:
> 
> Class: 
>   Process subclass IntervalEvent	
>   ControlConstruct subclass IntervalEvent
> ObjectProperty:
>   timeout: ProcessComponent --> IntervalThing
>   timeoutAbsolute: ProcessComponent --> InstantThing
> In class ProcessComponent's definition (restriction on property):
>   begins
>   ends
>   timeout
>   timeoutAbsolute
> 
> After you remove 
> 
>   Process subclass IntervalEvent
>   ControlConstruct subclass IntervalEvent
> 
> "begins" and "ends" temporal property restrictions will have to be removed
> (or re-defined) from the definition of ProcessComponent, since they are
> based on the the above subclass relationship.
> 
> About "timeout" and "timeoutAbsolute", based on Mark Burstein's email:
> 
> 
>>Process Instances now represents either a set of unrelated intervals 
>>(like the old process class) or else something that is not an event at 
>>all, but is just a spec for one.
> 
> 
> it makes sense to me to still keep them as possible temporal properties of
> ProcessComponent.

Good point.  That is, if "timeout" specifies a length of time that is allowed for 
the completion of (each execution of) a process (or control construct), then I think 
that does make sense.

But I don't think we can keep timeoutAbsolute.  I think that property was meant to 
specify an *absolute time* at which a process execution times out.

> 
> 
>>I've also removed the cardinality restrictions on temporal properties,
>>which were based on these subclass relationships.
> 
> 
> I don't understand why you (only) removed the cardinality restrictions on 
> temporal properties (which I guess are "begins" and "ends", right?).
> The problem is the whole restriction, not the cardinality, as they are
> using owl:maxCardinality="1"...

Right.  Actually I removed the entire restriction, for "begins", "ends", "timeout", 
and "timeoutAbsolute".  I am now planning to put it back for timeoutAbsolute.

Thanks for your comments,
-- David

> 
> Thanks,
> 
> Feng
> 
> 
> On Mon, 3 May 2004, David Martin wrote:
> 
> 
>>Bijan Parsia wrote:
>>
>>
>>>I notice that:
>>>
>>><owl:Class rdf:ID="Process">
>>>  <rdfs:comment> The most general class of processes </rdfs:comment>
>>>  <rdfs:subClassOf rdf:resource="&time;#IntervalEvent"/>
>>>...
>>>
>>>So, it follows that AtomicProcesses aren't instants, which, while I 
>>>accept that, could perhaps complicate some aspects of reasoning with 
>>>them. (E.g., while it's great if you know that an AP is going to take up 
>>>a certain amount of time, since you may be trying to figure out the 
>>>overall time for a some composition, but you typically don't want, i 
>>>take it, (relevant) change to happen during the AP (at least, from 
>>>"inside" the AP).)
>>>
>>>More importantly, I don't think Processes, as we've currently defined 
>>>them (i.e., as Process *definitions*) are TemporalThings at all. For 
>>>example, it makes no sene to say that one definition is *before* another 
>>>(it does make sense to say that this or that Process occurrence is 
>>>before that other one, or that this Process execution is before this 
>>>other one).
>>
>>OK, later today I've planning to remove both
>>     Process subclass IntervalEvent
>>and
>>     ControlConstruct subclass IntervalEvent
>>
>>from the developing 1.1 Process.owl file
>>(which, please note, is an incomplete, inconsistent *draft* at present).
>>
>>I've also removed the cardinality restrictions on temporal properties, 
>>which were based on these subclass relationships.
>>
>>(This removal of the time ontology use) is one of the more regrettable 
>>aspects of our switch to PAI.)
>>
>>Of course, if and when we develop an ontology of process "execution 
>>traces" (as we have discussed in the past), we can again use the time 
>>ontology in this way, with execution traces.
>>
>>In the meantime, I'm not clear what, if anything, we can say about time 
>>in Process.owl.
>>
>>Feng, do you have any guidance regarding this?
>>
>>Thanks,
>>David
>>
>>
>>
>>
>>
> 
> 
Received on Tuesday, 4 May 2004 01:38:57 UTC

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