Dear Simon,
Quite.
The truth is that there are multiple ways in which roles can be represented. The data that needs to be held is the same for any of them. For a student for example you need to know when they started being a student, and when they finished (if they have) and what their student ID is. This is going to be held as a record somewhere, the rest is mostly about what you are going to call it. It might be a temporal relationship, it might be a state, it might be a qua-individual. That will be a matter of the philosophical underpinnings/prejudices that influence the design.
The most common mistake I see in models of roles is roles being treated as subtypes of the role-player. As long as you have not fallen into that trap, the chances are that what you have done is “not wrong”.
Regards
Matthew West
Information Junction
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From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx [mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Simon Spero
Sent: 04 October 2012 21:17
To: [ontolog-forum]
Cc: Gian Piero Zarri
Subject: Re: [ontolog-forum] Person, Organization, and Citizens United vs. The Federal Election Commission
Just as a quick check- how many other people here have designed, implemented, and deployed systems for person information management for large RI universities integrating faculty,staff, student, and other affiliates from heterogenous sources.
Am I the only one who was stupid enough to model student, staff as role entities referring back to a person entity, with all the role specific properties associated with the role object?
I thought I was being clever, letting meta-properties like "ferpa directory information release ok" be associated with these student objects.
Sure, the existence of these role objects may have been rigidly dependent on the person job having at some point existed, but I had no idea this was so modally unacceptable.
Yet another scandal that might be blamed on the alethic department.
Simon
On Oct 4, 2012 11:53 AM, "Gian Piero Zarri" <zarri@xxxxxxx> wrote:
Doug,
On 04/10/2012 16:24, doug foxvog wrote:
> On Thu, October 4, 2012 07:00, Gian Piero Zarri wrote:
>
>> ... solutions in the "qua-individuals" style like
>> those proposed by Masolo and Cie. are not only inelegant but, mainly,
>> actually impracticable because they lead to a quick proliferation of
>> individuals: "JOHNquaHarvard-student" becomes, in fact, an instance of a
>> concept like "student". And "student", moreover, is a "transient
>> property" that cannot be instantiated.
> If you only allow the instantiation of rigid classes, then, by definition,
> "student" cannot be instantiated. One can instantiate an instance of
> "person" -- or whatever the nearest subsuming rigid class is -- and
> associate the role "student" with it in the appropriate timeframe.
>
> However, Masolo & Cie do allow the instantiation of non-rigid classes,
> such as "student". Since they DO it, they CAN do it in their system.
This is a sort of casuistry. Apart from the logical mistake of declaring
instances of "student" or "customer", can you imagine a PRACTICAL system
of reasonable dimensions where you are continuously obliged to create
new individuals for specifying all the possible everyday behaviours of
John (and of all the others)? The management of individuals is
particularly tricky and costly in concrete KBs.
Regards,
G.P. Zarri
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