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3 CASE STUDY
We have been working with a large corporation to
employ OSTRA to develop their SOA initiative.
This industrial partner is interested in using SOA
technology to improve their business flexibility and
to enable better integration between its divisions and
products (Bloomberg, 2003). However, the company
size is a challenge for the implementation of
enterprise-wide initiatives, as there are many
conflicting interests and a myriad of existing
applications and competing technologies. Therefore
we have started the work in one of their division
Plant-Wide Systems (PWS) and have been preparing
to deliver it at other divisions.
3.1 Inception
The first step in the application of the OSTRA
framework involves the definition of the SOA group
and SOA concepts. The SOA Group contains a
business leader, the manager, to provide a view of
the customer needs and enterprise directions; a
technical leader, the systems architect, to provide an
overall perspective of the applications; product
architects, to contribute with their detailed
knowledge on each application; and external
consultants, to provide an understanding of SOA
technology. Moreover, in order to discuss
information pertaining to SOA concepts, regular
meetings were organized with core members of the
SOA group. The results of these discussions were
consolidated into a presentation to the entire SOA
group and were compiled in a document that served
as the basis for a conceptual whitepaper.
3.2 Elaboration
Although several opportunities were identified, it
was decided that the initial focus would be on
improving application integration, since this can
produce more visible and immediate results than
decomposing existing applications into services. A
new application named InfoLite has been selected as
the pilot project to illustrate the benefits of an SOA-
approach in practice and to establish initial standards
for SOA development. Furthermore, an overall plan
for the transition has been established, which is
depicted in Figure 3. The plan involved using the
results of the development of the opportunities to
demonstrate the value of an SOA to their
applications and to obtain approval at the current
business division, securing a budget and eventually
triggering the SOA adoption for the entire system.
In the current organization of the enterprise, each
division has a certain degree of autonomy to take
their own decisions, and therefore it provides a
natural structure for the Governance Model.
Furthermore, initial investigation has started on
policies and procedures, especially in terms of
naming conventions and optimal services
granularity; this investigation is being assisted
through collaboration with the other information
team. In order to facilitate reuse by different teams,
specific industry standards have been adapted to
build a vocabulary of valid verbs to use as service
operation names, and to provide recommendations
on the names and scope of the services.
Figure 3: High-level plan for the transition.
3.3 Implementation
In the implementation phase, the pilot project
InfoLite was developed. Figure 4 displays an overall
view of the initial situation. Three applications from
a plant control division are represented: Limit
Control, Incident Intelligence, and Operator
Assistance. Also depicted is the Plant Information
application, which is used by managers to control
the production of the plant at the next higher level.
PWS platform and PWS database provide
information models such as equipment structures for
the Limit Control and Plant Information applications
at enterprise level. The Limit Control (LC) database
is depicted separately to assist in conceptualizing the
models at domain level. Incident Intelligence
retrieves their equipment structure, as well as other
data, from the Limit Control database. However,
these applications retrieve data directly from the
Limit Control database and need to deal with
problems such as synchronization and dependency
on the Limit Control data structure. If designed
AN OVERVIEW OF THE OSTRA FRAMEWORK FOR THE TRANSITION TO SOA
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