Semantic Composition of Web Portal Components - End User Computing Challenges and Technologies: Emerging Tools and Applications - page 175

from the classes they are associated with. A full
introduction to OWL is beyond the scope of this
chapter. Therefore, we will restrict ourselves to
explanations necessary for the purpose of gaining
an intuitive understanding of Figure 4.
Inheritance relationships are rendered as arcs
with large white arrow heads, whereas (instance)
references are shown as arcs with small open ar-
row heads. References merely represent a special
kind of property. Their range can be instances of
classes as well as the concept classes themselves.
Property participants of class Act is an example
for an instance reference. While the base range of
property participants covers all values (instances)
of class Entity, its range has been restricted in class
Act to values of class Actor . Further restrictions are
shown in subclasses of Act. Note that in the ezOWL
visualisation, inherited properties are repeatedly
listed in subclasses.
We assume that the reader has an intuitive un-
derstanding of the concepts depicted in Figure 4
except, perhaps, for the part that deals with clinical
documents. This part is based on the HL7 Clinical
Document Architecture (CDA), which structures
medical documents in terms of sections and entries,
the latter not shown here. This model is based on
the idea that the same type of section can appear
in different types of documents; for example, the
slit lamp exam report section can appear in docu-
ments other than a cataract assessment.

The part in Figure 4 that deals with clini-
cal documents is most important from a portal
administrator's point of view, because sections
would be represented by WPC in the component
library and clinical documents would be represented
by portal pages composed by end users, such as
physicians.

semantic typing of wpC interfaces

With a PDO, it becomes possible for the admin-
istrator to attach semantic to interfaces of portal
components. For simplification purposes, we
will describe how this is done for primitive WPC
interfaces only. The main idea is to attach to each
(primitive) WPC interface a reference to a prop-
erty of a PDO concept. Figure 5 illustrates this
graphically by adding concepts for WPCs and
their properties to the PDO from Figure 4. (Note
that Medicare_PDO_element is the root concept
in our PDO.) A primitive interface has now a
semantic label consisting of two properties: PDO
Element references a concept in the PDO and
Element property references a property of this
concept. Using the dot-shorthand to separate the
two parts of a semantic label, an example would
be “Patient.ID” for a WPC event interface that
can accept or emit a patient identification.
Besides semantic typing, another notable
feature of the model in Figure 5 is that it shows

Figure 5. Structure of semantic WPC interface