Applying Semantic SOA Based Model to Business Applications - Enterprise Information Systems Design, Implementation and Management: Organizational Applications - page 4

Figure 1. Activities within SOA

• UDDI-Registry: Also known as service

broker, it is responsible for making the
access information of both Web Service
interface and implementation available to
any potential service consumer, and cate-
gorizing the results in taxonomies. UDDI-
registry defines the way to publish and dis-
cover information about Web Services.

intra- and inter-enterprise integration. However,
developers will require automated systems for
service discovery in order to enable further Web
Service interactions with even less human effort.
UDDI exists precisely for this reason. However,
unless the service consumer knows the exact form
and meaning of a service's WSDL specification in
advance, the combination of UDDI with WSDL
and coarse-grained business descriptions are not
enough to allow fully automated service discovery
and usage of Web Services.
Secondly, the service invocation problem
which can be described in the terms of dealing
with systems that might differ in its invocation
method by providing different interfaces (public
processes) for the semantical same operation
(Bussler & Fensel, 2002). For example, one sys-
tem offers product purchasing with one single
invocation while another system requires first
the process of creation a user, then activation of
the user and finally the purchase of the product.
Therefore, in the first system, one invocation
completely defines a user whereas in the second
system several interface invocations are necessary

• Web Service Consumer: The service con-

sumer (requester) or Web Service client
locates entries in the UDDI registry us-
ing various searching operations and then
binds to the service provider in order to in-
voke one of its Web Services.

Figure 1 illustrates the mechanism of publish-
ing, discovering and binding Web Services in
SOA concept.
In this chapter, we are going to discuss the
problems of the existing SOA-based solutions at
the discovery and invocation phases. Firstly, tra-
ditional SOA service discovery problems can be
described as follows: Web Services appear to be-
come more widely adopted allowing much broader