[DPF] Properties with both values and child properties? RDF graph vs. DPF tree.

Hi Jeremy and Mark,

This message contains a response to comments on

http://www.w3.org/TR/2004/WD-DPF-20041122/

r1. Properties with both values and child properties?

The specification of a DPFProperty allows for a property
to have both a value and to have children.
No examples of the use of this feature is shown.
It would be less confusing to have two different
subinterfaces of DPFProperty: one that had a value but
no children, the other that has (possibly 0) children,
but no value.
In the latter case, it then seems that the collection
of children of a DPFProperty describe an (unnamed) resource
that is the value of the parent DPFProperty,
e.g. in Figure 2, the property "GPS" has a (resource) value that
is described with two properties "IBM:GPS" and "NOKIA:GPS"

r2. DPFProperty hierarchies as RDF Graphs

We redrew fig2 as in the attached PDF file.

We simplified the lines, so that they just show
parent/child relationships, and not sibling relationships.

We added arrows to the lines rather than relying on the
vertical convention of parents above children.

We clarified that the labels (except DPF component) were
describing the relationship between parent and child,
rather than describing the child

We also added a little bit more, to show how a value
could be drawn in the picture, as a leaf node, with the
value labelling the node.

This picture then is an RDF graph, and conveys much of the
information of fig 2.

The (implicit) resource values of the properties are made explicit
as unnamed circles, and the property names are used to appropriate
link the ovals in the diagram.

This diagram does not suffer the problem of figure 2 that the labels
GPS and IBM:GPS and NOKIA:GPS are used to show the relationship between
the parent node and the labelled node, whereas the label "DPF Component"
does not, which is visually confusing.


Figure 2 has been re-drawn (attached). The intent of the diagram is
not meant to illustrate a RDF graph structure.

-Keith Waters