A Service Component Model and Implementation for Institutional Repositories - Advanced Design Approaches to Emerging Software Systems - page 70

Figure 4. Comparison of the three methods of DRSC object creation

of the digital resource. Once complete, a SaaS
interface is provided for the user to manage the
digital resources. In all, these three methods are
from local installation to remote service, from
complex to easy (Figure 4).
After a DRSC object is created, there are two
kinds of user groups: end users and developers.
If end users only need the basic functions of add,
delete, update and search, they can use the Web
interfaces provided. However, it is typical that
end users require more functions and/or different
user interfaces. If this is the case, the developers
can utilize the programmable interfaces provided
by the DRSC object to build new functions and
user interfaces. Furthermore, not only can the
DRSC object be used in a new digital resource
management system, but it can also be invoked
from the existing software systems to support the
new digital resource.
As apparent, the second and third methods to
create a DRSC object utilize web resources. Ob-
viously, this causes a security concern in relation
to the distribution of the DRSC object. However,
while the security problem is not solved by the
components themselves, it is resolved through
appropriate management at the system level and
the data level that will be explained in Section 5.
To continue, the assistant tool is implemented
in Java. However, the DRSC model is only a

specification that is an application of SCA in the
digital resource management field. Importantly,
other programming languages and tools can also
be used to create the components.
In this section, we present a digital resource
service component model which is different from
the traditional digital objects. This model is based
on SCA specifications. A DRSC object is com-
posed of five atomic components: ID, Metadata,
Content, Log and Annotation. The composition
of a DRSC object is flexible by adopting different
Internet transportation protocols. The processes
to analyze and create a DRSC object are given.
We also discuss the usage of a DRSC object. In
the next section, we will focus on the system
architecture.

4. ARCHITECTURE SUPPORTING
DIGITAL RESOURCE SERVICE

Our architecture includes the function modules,
the invoke relationships, and the transportation
methods of messages. The architecture describes
how an IR manages digital resources based on
DRSC model (Figure 5).
To further describe Figure 5, an institutional
repository is composed of five layers (Network
Infrastructure Layer, Cloud Layer, ESB Layer