|
Section 2 - Web-based Information
System Development Life Cycle
There are currently several proposed development life
cycles for Web-based information systems. WIS
development has been regarded as a process,12 and, as such, it is possible
to divide this process into various phases in order to
introduce control and minimize risks. Some of the
current models of a Web-based information system
development life cycle are: Ginige's
WIS development process13, Pressman's
framework of activities for Web applications14, Takahashi's
and Liang's flow of analysis and design for
Web-based information systems15, and Fraternali's
Life cycle of a Web Application16.
All four models have a similar basic framework,
including an analysis phase, a design phase, a Web site
construction phase, and a maintenance phase. In order to
address the evolutionary nature of Web-based information
systems and to ensure the generation of complete
requirements specifications, all of the above frameworks
include some form of iterative approaches. Ginige
suggests using the Spiral
Development Process, Fraternali advocates Prototyping,
Takashi and Liang propose an iterative process between
scenario
analysis and architecture design, and Pressman warns
that his framework's "activities are applied iteratively
as a Web-based system evolves."17 However, the choice of a
methodology also depends on the complexity and size of a
Web-based system, as well as on the types of Web
applications being considered. For example, Ginige
advocates the Waterfall
model for simple Web sites that do not require an
iterative approach.
Current available development methodologies for
Web-based information systems have focused on the design
and implementation stages of the WIS development life
cycle. This is mainly due to the fast environment within
which Web-based information systems have grown and in
which organizations have struggled to keep ahead of
technological changes to maintain their competitive
advantage. Among the methodologies proposed and modified
for WISs development, hypermedia methodologies have been
the most prevalent.
"The first proposal has been HDM [Hypertext
Design Model], based on a semantic model of
information in the application and the study of
navigational patterns. HDM has been developed in
subsequent approaches, e.g. OOHDM [Object-Oriented
HDM], based on an object-oriented approach to
multimedia applications design and RMM [Relationship
Management Methodology] starting from entity
relationship schemas in the first design phases."18
However, these methodologies are database-centric
and are best suited for highly structured systems.
Recent developments have included user-centered
methodologies such as W3DT [World Wide Web Design
Technique] - which was developed "to support the
requirements of unstructured, hierarchical WIS and to
visualize them from a recipient's perspective"19 - and its extension - which
was developed to reference modeling of commercial WIS -
eW3DT [Extended World Wide Web Design Technique].
However, when developing complex Web applications,
Scharl recommends integrating "the user-centric eW3DT
with technical, more database-centric data models like
RMDM, HDM, OOHDM, or any of the other approaches based
on entity relations."20
Independent from the methodologies used during
the development of a Web-based information system,
although the overall development process of a Web-based
information system may seem similar to that of a
traditional information system, there are significant
differences in the elements that need to be taken into
consideration during the requirements analysis stage of
a WIS development life cycle.
|
