October 2007 Volume 10 Number 4 - Educational Technology ...

Evaluation through prototyping and user testing
Incremental prototyping was used to evaluate and refine the main elements of the design specification and to develop
IMMEDIATE into a fully operational network. The approach taken was to focus upon meeting the requirements of
the Learning Shell as the front-end of the system and then to address networking, authoring and administration issues
in the context of supporting those requirements.
The Learning Shell user interface has been assembled in Delphi from reusable “drag and drop” software components.
Each of these encapsulates a particular learning element such as a student notebook or a lecture presentation. They
are built to a template to ensure consistency across the system and are self-contained in terms of learning
functionality, only needing to call the Shell API to access or update learning content. An algorithm maps each
learning content file to a particular learning component and topic in the course, enabling the system to synchronise
components by topic and provide context-sensitive help. The learning support system is built upon a database of
definitions, elaborations, references and URLs linked to keywords associated with each topic in a course. This
components-based architecture provides a robust, modular structure capable of incorporating more advanced
technologies as appropriate.
As a network user interface in an internet-based client/server network, the Learning Shell has some functional and
architectural similarities to a platform-specific web browser such as Microsoft's Internet Explorer that is tightly
linked to the underlying operating system. It is built around a Controller module providing an API through which
interface components interact with each other and with the reference model layer (Figure 1). The model layer is a set
of data structures and related operations, each of which models a different aspect of the learning computer and its
current state. The System Model, for example, defines the different study modes available in a course, and maps
individual learning components to each mode.
Desktop
Enables user to
interact with the
system controller
to change modes,
launch interface
components, etc.
Operating
System API
Called by
components
for their
internal
functionality
User Info
Enables system to
directly collect info
from the user - logon,
backup drive,etc.
Generic Learning
Component
Tools available in any
mode. Managed by
the user, e.g. Student
Notes
Manager Manager Manager Manager
Student Model
Holds student
info needed by
system & not
stored
elsewhere,
e.g. current
topic & mode,
password
System Model
Maps
components to
modes and
holds other
static info
about system
System Tree
Maps structure
of course.
Stores
dynamic info -
nodes (topics)
visited or
completed, etc
Figure 1. Learning Shell architecture
Resources
Model
Maps stored
files to
learning
components
Mode-Specific
Learning Component
Accessible only by
changing mode -
managed by system
e.g. Lecture Notes.
Controller
All interactions between components are channelled through here. Manages the
interface components - mode changes, etc. Interacts with system components via
respective managers.
Learning shell directory system
Manager
System
Database
Integrates
messages &
learning help
The Controller plays an analogous role to a browser’s controller, which manages the other browser components and
calls on them to perform operations specified by the user (Comer, 1999, p. 427). However, the Learning Shell
Controller, through reference to the model layer, has additional capacities for managing the interface to simplify and
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