Re: modelling issue?

Pat,
thanks for reply

If we consider for a moment the semantic web as an 'enterprise',
uncertainties = risks , resolving these issues/ possibilities may result
into  overheads and difficult management decision (which the majority of
managers cannot really deal with hence set aside for future generations to
handle)

briefly, below


>
> Well, this may be partly caused by the various terminologies in use, eg RDF
> "property" is sometimes called a "relation" and RDFS/OWL "class" is
> sometimes (confusingly) called "property" and sometimes called "set".
>

this alone would be enough to cause the average working ontologists some
headache (possibly leading onto bigger existential questions) -  (semantic
consistency anyone? - glad to see the workshop coming up)

>
>
> No, there is no actual rule. In general, its often a good idea to provide
> all information that you have available, so if indeed you know the domain
> and range then you might as well write that down. In doubt, it is fine to
> specify a more vaguely defined superclass: that is always harmless and might
> be useful.
>
> sounds v heuristic


>
>
>>>
>>> class:relation:class
>>>
>>>  but also
>>> class:attribute:value
>>>
>>> Of this i would like some confirmtion (is this right?
>>>
>>
>> No. Or at any rate, not if I am following you. First, the first item
>> (subject) of the triple isn't necessarily a class.
>
>
> okay, I have always assumed that the subject *is* a class, any hints as to
> what are my options?
> or what chapter of the book/tutorial I can find the relevant info?
>
>
> Well, there is no info because there are no constraints. The subject of an
> RDF triple can be anything. If you can refer to it using a URI, then it can
> be a subject, i.e. you can say something about it.
>
>
and if not?

>
>
> scroll down to FIG 7
>
>
> Again. I am afraid that I have no sure idea what this diagram is supposed
> to mean. I will however make some guesses, based in part on your
> translation. Correct me if I am wrong.
>

The way I see it (since we are all mere interpreters) all the boxes are
'things' (I really like that view of the world)
and all the lines are relations into things

Note: I agree that describing the world is messy, and that pointing to it
should be simpler, but 'pointing to things'
is by no means trivial. I have recently come across 'organisational
semiotics' (R Stamper) and wonder if there is anything to learned there. Got
some easy example, of where we think we are pointing to something, but
people see something else
(the finger and the moon example is one of them)

Take the example of
> Organization --Has -- Affiliated_Person, which is a long slightly curved
> line on the LH side of the diagram. Does this mean that things in the
> Organization class, i.e. organizations, all have an affiliated person who is
> a member of the class Affiliated_Person? Because if so, this is not
> adequately represented by a single RDF triple.
>

ah, that sounds possible, so that would have to be many triples?
That takes me to the 'concatenation question' - is it true that a thing that
is a subject in a triple cannot be
anything else in another triple in the same vocabulary?
If so, how can we concatenate and/or merge vocabularies (apologies if the
question is too big/open)



>
>
> So, to sum up, after realising that we can use RDF equall to triplify
>
> ORGANISATION   HAS     CONTACDETAILS
> (class)                   rel        (class)
>
>
> This says that the HAS relationship holds between the actual classes, not
> between the elements of the classes. Is this really what you intend to say?
>

in the example above  yes, the example below I am looking at the stuff in
the box (relation between the class and its elements)


but also

ORGANISATION     IS        OFTYPE

or
ORGANISATION     HAS    WEBSITE




is this 'versatility' of using RDF in the same way for either/both

a) what is referred to as an RDF weakness?
b) never been thought of as a problem when modelling data?
c) related to the intensional /extensional discussion referred to as above?

PDM