UCD and DM

[Brian Thomas]

On Thursday 09 October 2003 02:39 pm, Roy Williams wrote:
> Brian and Ed,
>
> > > > Our
> > > > view is that the UCD are concepts that will inherit (as a class)
> > > > from the quantities
>
> In the UCD group we are considering a model based on triples: [Concept,
> Property, Value]. Each part of the original tree can now play a role in one
> of the triples. For example, in the sentence "My apple weighs 400g", we
> have a Concept (apple), and an instance of the Concept (My apple), then the
> property (weight), and the value (400g).
>
> (1) Ed's model has some overlap here. For example, the value part (400g) is
> an instance of "quantity". The units and data types makes a good fit here.

	Well, we both developed this model, and view it more this way: the parent 
 	class of the quantity holds the  'concept' part.

	Consider this diagram: 
              http://nvo.gsfc.nasa.gov/QuantityDataModel/index_html_74785d83.png

	Properties are nothing more than quantities and may be added by adding 
        child quantities (concepts) to the parent concept. consider:

    http://nvo.gsfc.nasa.gov/QuantityDataModel/index_html_m740e0b10.png

	so we view the quantity as being a bit broader than that you define. It is
	the basis for both property and concept and can serve as the machinery
	underlying both parts.

> (2) However, I do not understand what is meant by "VO_Class". Is this the
> class of the Concept (Apple), or is it about the property (Weight)?

	Ed added this to the model. He can describe it better than me.

>
> (3) Both DM and UCD groups are interested in what types of quantities (or
> values as we call them) can be used for what types of properties? In other
> words, if I say "My apple weighs {0.1, 0.3, -0.4}km/sec", how can a formal
> system figure out that this is wrong?

	I believe so because you can limit the association between the concept
	"apple/units" to just be mass in an ontology (whether ontology 'tech' is
	up to this is not for me to answer..)

				-b.t.

> Roy

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  * Dr. Brian Thomas 

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  * Goddard Space Flight Center NASA

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