Applying Semantic SOA Based Model to Business Applications - Enterprise Information Systems Design, Implementation and Management: Organizational Applications - page 14

Figure 3. Type Inheritance

it first seemed, the separation adds no advantage
to a system - it will slow down the system by
having additive communication traffic.
As answer to the question of why this extra
layer has been used? We have to consider some
issues. First issue to consider is the reusability of
existing Web Services: Normally, a Web Service
does not provide any semantic annotations and in
order to use it in the semantic SOA-based model,
some changes have to be done on the Web Service.
From the provider's perspective the problem is
that there are different annotations for the used
semantics and as a result, the provider has to imple-
ment different interfaces for its Web Services.
Second important point is the fulfillment of
a semantic meaning: It is not correct to annotate

a Web Service in order to be adapted in the se-
mantic SOA-based model, rather there is a need
to validate whether a Web Service is dealing with
information like expected or not. This means that,
an annotated Web Service has to have exactly the
same data ranges or data types like the annotation
describes. And as a result, a Web Service needs
to be validated against the semantic descriptions.
The bundling of the annotation together with
the test functions in a separate layer reduces the
programming effort by enabling the reusability
of those functionalities.
The third point to consider is the expressiveness
of Web Services themselves: While data structures
that are modeled to describe an object are often
primitive, there is a high probability that a Web