Re: "shape" as a relationship, not a class

Hi Irene,
  I have also struggled as whether information objects (e.g.
documents/records) really need to be differentiated from the objects that
they mean to describe. Ultimately, it comes down to what you (and others)
will say about identified entities. Just as Arthur suggested, there are
some properties that strictly belong to records (e.g. creator, modification
date), while other properties strictly belong to the object of interest
(e.g. for a person - name, birthdate,  gender, etc). Having this
delineation is not only useful to disambiguate which object you are
referring to, but is also useful to capture changes made to records and the
provenance of assertions collected. It's really a whole other level of
description, which is necessary for people like me. It's technically
important for me that we make the distinction between a shape, and the
objects that it means to constrain.

m.


Michel Dumontier, PhD
Associate Professor of Medicine (Biomedical Informatics)
Stanford University
http://dumontierlab.com

On Fri, Feb 20, 2015 at 7:53 AM, Irene Polikoff <irene@topquadrant.com>
wrote:

> I believe that ³real word object² in the Semantic Web speak doesn¹t mean
> that it has a physical representation. It is also a concept.
>
> In that sense, a user account is as much of a real world thing as a
> person. One can create a class User Account to say that a user account can
> be created by someone (system administrator), that it has valid from and
> to dates and that it is an account of some person, etc.
>
> As for web documents, there can be a web document presenting information
> about a person as much as there can be a web document presenting
> information about a user account. And there could be multiple ways to
> render information about either a person or a user account.
>
> I have to say that while conceptually I understand the distinction between
> ³real things² and ³information resources², I still don¹t understand the
> practical application of the distinction after much reading. To me, the
> distinction has to do with some very particular viewpoint that is somewhat
> esoteric. After all, we are dealing with the world of data and software.
> We can¹t process anything, but information.
>
> Since I was struggling with this, I thought that may be making this
> distinction is really important for dereferencing (not that other, non
> Semantic Web systems don¹t display web documents) and I am missing some
> technical knowledge to get the ³aha². So, a year ago I¹ve asked three
> separate senior developers/technical architects who had shallow exposure
> to RDF but didn¹t come from the Semantic Web community to read on this
> subject and tell me if they understood it and could explain it. All three
> couldn¹t make sense of it. They just thought it was irrelevant. These
> folks are all fairly bright and capable with 7 or more years of technical
> experience.
>
> This is a limited experiment, for sure, but so far it confirms Holger¹s
> view that this is not something people care about or need to understand.
>
> Irene
>
> On 2/20/15, 10:15 AM, "Arthur Ryman" <ryman@ca.ibm.com> wrote:
>
> >Holger Knublauch <holger@topquadrant.com> wrote on 02/08/2015 05:36:32
> PM:
> >
> >> ... I am afraid the distinction
> >> between real-world objects and their representation drifts into
> >> theoretical realms that nobody outside of the RDF world seems to care
> >> about (and rightfully so).
> >
> >Holger,
> >
> >The distinction is important in some cases because if you fail to make
> >the
> >distinction, then when you read the RDF, it sounds like nonsense. The
> >classic example is the distinction between a person and a user account
> >owned by that person. A person is a RWO and should have a URI that is
> >different that the user account, which is an information resource (a web
> >document).
> >
> >A web document can have properties such as creator (a person), creation
> >date, modification date, etc. It makes sense to say that a user account
> >document has a modification date, but it is nonsense to say that the
> >person who owns the user account has that modification date (barring
> >coincidental plastic surgery on that date). FOAF makes this clear. This
> >whole topic is nicely discussed in [1], which is co-authored by your
> >newest colleague.
> >
> >[1] http://www.w3.org/TR/cooluris/
> >
> >
>
>
>
>