On Dec 20, 2010, at 6:01 PM, Michael Gruninger wrote:
> Hi Chris, (01)
Hey, Michael. (02)
> this example is not so clear-cut, (03)
I think it is -- in the context. ;-) (04)
> since there it is possible to interpret these statements within a process
>ontology such as PSL:
>
> • Jack and John are instances of Actor
> • Task is an subclass of Activity
> • WashWindows is an instance of Task
> • PushWashButton is an instance of Task
> • there is an occurrence of WashWindows done by John
> • there is an occurrence of PushWashButton done by Jack (05)
I think, as a description of the operation in question, you'd want to say that
*every* occurrence of WashWindows/PushWashButton is done by John/Jack.
(Indeed, it might even be false at the moment that there are any such
occurrences, since the ontology might be describing task assignments in a
planned operation rather than a currently functioning operation.) (06)
> Admittedly, there is no explicit process ontology in the original example
>that employs the distinction between activities and their occurrences, (07)
But I think that is exactly the problem. The document is explicit about the
ontological resources available and there simply *is* no process ontology
therein, implicit or otherwise. Thus, of the ontological categories they
provide, the only possible one into which WashWindows and PushWashButton can
coherently fit is CLASS. Hence, given the background ontology, it was a
mistake for them to classify those objects as instances of TASK rather than as
subclasses thereof. (08)
> but my point is that there is no need to say that WashWindows and
>PushWashButton are classes. (09)
Of course, given a richer ontology. So I'd put your point a bit differently:
by adding a proper process ontology like PSL to the ontology described in the
document, TASK could be conceptualized as a class of general activity objects
and, hence, WashWindows and PushWashButton could be conceptualized as instances
of, rather than subclasses of, TASK. (010)
Cheers! (011)
-chris (012)
> Quoting Christopher Menzel <cmenzel@xxxxxxxx>:
>
>> From the Car Wash example 3.3.2.4:
>>
>> As an important part of the car wash system, John and Jack perform certain
>manual tasks required for washing a car properly:
>>
>> • Jack and John are instances of Actor
>> • WashWindows is an instance of Task and is done by John
>> • PushWashButton is an instance of Task and is done by Jack
>>
>> Seems to me from the brief description that WashWidows and PushWashButton
>are supposed to be classes whose instances are actual atomic tasks — John's
>actual window-washings and Jack's actual wash-button-pushings. If so, then it
>seems to me that the little ontology fragment above is wrong and that, instead
>of the second and third lines, they should have:
>>
>> • WashWindows is a subclass of Task
>> • Instances of WashWindows are done by John
>> • PushWashButton is a subclass of Task
>> • Instances of PushWashButton are done by Jack
>>
>> Or something like that. (013)
_________________________________________________________________
Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/
Config Subscr: http://ontolog.cim3.net/mailman/listinfo/ontolog-forum/
Unsubscribe: mailto:ontolog-forum-leave@xxxxxxxxxxxxxxxx
Shared Files: http://ontolog.cim3.net/file/
Community Wiki: http://ontolog.cim3.net/wiki/
To join: http://ontolog.cim3.net/cgi-bin/wiki.pl?WikiHomePage#nid1J
To Post: mailto:ontolog-forum@xxxxxxxxxxxxxxxx (014)
|