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Fwd: triples/ toward RDFizing the schema

From: <paola.dimaio@gmail.com>
Date: Sat, 4 Oct 2008 19:36:44 -0700
Message-ID: <c09b00eb0810041936j283821ebo6eca554b7c522c06@mail.gmail.com>
To: public-xg-eiif <public-xg-eiif@w3.org>

Craig, thanks for reply
I find the comments below educational (learning something)
so I am forwarding them to the list to see if someone has something to add

yes, CAPS are ugly, only here used to distinguish S/O from p



cheers, PDM

and no, I dont have a cat !





---------- Forwarded message ----------
From: C H <craighubleyca@yahoo.com>
Date: Sat, Oct 4, 2008 at 9:59 AM
Subject: Re: triples/ toward RDFizing the schema
To: paola.dimaio@gmail.com


Feel free to forward this if a discussion ensues.  No need to bug the
list with it otherwise.

> I am startedt to think of the schema being worked out by
> Mandana as triples

Wise.  Astonishingly good tools exist for manipulating RDF triples.

> can someone correct the assertion?
>
> SUBJECT predicate OBJECT assumption:
>
> (whereby SUBJECT and OBJECT correspond to the entities in
> the schema, and the predicates to the relationships)
> would this be right?

Yes.  Another word for predicate is "relation" as in
entity-relationship diagram.  Generally the word "relation" is
reserved for the very strict style of table used in relational DBs and
the word "relationship" for ERDs which are much much looser.
Predicates are somewhere in between in the scale of strictness - a
wide range in between from pure logical predicate to vague assertions
piled up in something like semantic mediawiki (a tag scheme that
embeds RDF data into mediawiki pages, extraordinarily useful)

> question (do we have to model all the triples for the schema to work?)

No, but any kind of automated processing will stop dead if you don't
reduce all the relations to three-folded SPO
(subject/predicate/object) before you ask the robot lawyers to take
over.  They may do very strange things like sue your cat if you have
failed to reduce all the constraints to something they understand.
Try not to give them their own expense account, either - robot lawyers
can run up quite a bar bill at the gas bar.

By robot lawyers I mean RDF reasoners and so on, of course.  What else?

> AFFECTEDPERSON needs RESOURCE

Suggests others like "affected_person needs refuge_instructions" -
this ALL-CAPS thing is bad news, it prevents us from writing readable
sentences.  When an [[affected_person needs refuge instructions]] it
would be best to just be able to write it like that because then
humans and machines can both read it with no translation (assuming _
equates to space when rendered).

> ORGANISATION has CONTACTPERSON
>
> ORGANISATiON has CAPACITY is RESOURCE (N TUPLE)
>
> RESOURCE has TIME/LOCATION/OTHER ATTRIBUTE

While you're using them right here, be careful with preposition predicates.
An "is" and "has" must be used very specifically, usually by "is" we
mean "is-a-kind-of" and by "has" we mean "has-characteristic" or
"has-component" or "has-resource" (different things, a characteristic
is an inseparable attribute, a component is required for it to work
properly and a resource is something it can share or give away without
failing).

Consider also the time relationships required to deal with a temporal
database.  Korzybski said "is" and the verb "to be" were questionable
at best and could mean too many things, crossing the actual
operational time bindings we use in practice.  In real reality, we are
*remembering* or *explaining* the past which is different from
*sensing* or *comparing* the present state to other things present,
both of which are different from *envisioning* or *predicting* the
future.  The use of "is" and "are" in that sentence is the most basic
and if you don't respect that distinction you get into trouble - for
instance, confusing historical data with some future projection in
order to get some entirely bogus present "trend line".

(where economics goes wrong...)

> does this make sense to anyone on this list, or am I
> enterering another planet? etc etc

Makes perfect sense to me.  But I may have to ask a robot lawyer.  I
hope you don't have a cat.

> Paola Di Maio
> School of IT
> www.mfu.ac.th
> *********************************************






-- 
Paola Di Maio
School of IT
www.mfu.ac.th
*********************************************
Received on Sunday, 5 October 2008 02:37:22 GMT

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