CRITON: A Web-based Courseware Design Tool

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12 Νοε 2013 (πριν από 3 χρόνια και 9 μήνες)

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1

CRITON: A Web
-
b
ased Courseware Design Tool


Paris Avgeriou, Symeon Retalis, Emanuel Skordalakis

{pavger, retal, skordala}@softlab.ntua.gr


NATIONAL TECHNICAL UNIVERSITY OF ATHENS

DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING

SOFTWARE ENGINEERING LABORATORY

15780 Zogr
afou, Athens, Greece

TEL: ++301 7722487, FAX: ++301 7722519


Abstract

Education and especially open and distance learning has adopted the use of the Internet
and the Web. Main emphasis during the development of web
-
based instructional
systems is given to t
he engineering of courseware, which needs to take place with the
aid of a methodology in order to assure high pedagogic quality, maintainability and
scalability. A methodology consists of methods that are applied during the development
phases. It is essent
ial that methods are supported by tools, which can ease and speed up
the development process and enforce the correct use of the principles that methods
define. The design phase is one of the phases that lack sufficient support from CASE
tools. This paper p
resents CRITON, a cross platform tool built to support a web
-
based
courseware design method within a homogenous environment.


Keywords
: courseware, CASE tools, hypermedia, distance learning, design.

1.

Introduction
-

Motivation

Information technology has bee
n utilized in education since the early
development of computers, and nowadays with the availability of computer networks the
prospect is even better. Instructional systems in various educational institutes, such as
schools, universities and training cente
rs, enriched the instructional or training process
with the use of computers in a limited set of courses, mainly concerning computer
science itself. However, the explosive growth of the Internet and the World Wide Web
set a milestone for the support of the

teaching process by computers and networks,
practically for all curricula.

Educational research has been seeking ways to solve modern instructional
problems that have come up mainly because of the vast technological advances and the
transition from the In
dustrial Society to the Society of Information. The latter has
created the need for life
-
long learning so that people can keep up their professional skills
with the current trend. However, conventional training methods have proven to be
inappropriate and e
xpensive [1] for fulfilling these learning needs. Also traditional
secondary and higher education is obligated to adopt modern technologies and take
advantage of them, as they can offer assistantship in cases where teaching in classroom
fails, due to restr
ictions in time and place of learning, poor communication among
learners and teachers, text
-
based content representation. In general there is an urge to
turn to more open instructional systems, that place the students in the center of an

2

integrated environ
ment of learning resources and offer them a variety of tools for
communication and active learning [2].

WWW is an open, globe
-
wide platform that can be used in various ways in
education in order to facilitate multiple instructional services. Based on these

services,
the uses of the WWW in education, can be modeled into various categories [3]:



information based models (WWW is used for retrieving information, like in Virtual
Museums, digital libraries, etc.)



teaching media based models (WWW is used only for d
issemination of educational
material to distance students, i.e. course descriptions, educational software, etc.)



enriched classroom models (web
-
based courseware is developed and used
complementary to traditional classroom
-
based teaching material)



virtual c
lassroom models (WWW is used with emphasis on collaboration and
computer mediated human interaction)

In this paper we concentrate on the enriched models, that propose web
-
based
instructional systems which incorporate a special kind of educational software
named
web
-
based courseware (WBC)
. WBC should be regarded as a mosaic of learning
resources, constructed using a variety of languages, like mark
-
up languages (HTML,
XML), scripting languages (CGI, JavaScript) and other programming languages (Java,
Perl). Th
e student uses a common web browser to navigate through and interact with
these resources.

The construction of high quality WBC within specific time and fund limits is
not an easy task, and there is a need for development methodologies. In accordance to
t
he definition from software engineering practices, a
methodology

is a set of process
models, methods, tools, documentation aids and guidelines that help the developers in
building pedagogically effective WBC, respecting the constraints imposed in time and
resources. Such a methodology, of course, is not a mere collection of elements but
advocates specific instructional theory and development philosophy.

While other types of educational software have existed for a few years and their
development has aged and

reached certain maturity, web
-
based courseware development
is still very immature. Web
-
based courseware development cannot be easily performed
with already existing methodologies that are used for other types of educational software
because they do not ca
pitalize on its specific hypermedia characteristics and its
component
-
based nature [4]. There is still a great deal of work to be done on formalizing
process models, defining methodologies or design models [5]. Also, CASE (Computer
Aided Software Engineeri
ng) tools can significantly promote the efficiency of
development work. Regretfully WBC development processes lack CASE tools that
could support, for example, the analysis, design or evaluation phases [
6
], with the
exception of low
-
level implementation too
ls, such as web page editors.

In this paper we do not intend to tackle the WBC development process as a
whole but rather to focus on the design phase by giving an overview of a method, called
CADMOS
-
D
(esign), and analytically presenting its support tool, n
amed

CRITON
.
Good design is crucial, as it can provide a blueprint for the communication of the
development team with the client, as well as for offering guidelines and accelerating the
implementation process. It can also provide an analytical guide for th
e maintenance of
the WBC, and is the best way to ensure scalability of the application. An efficient design
tool is required in order for the design process to be supported by a specialized, uniform,
integrated environment.


3

The
CADMOS
-
D

method is one of th
e methods incorporated in a web
-
based
courseware development methodology called CADMOS [7
]. It follows the object
oriented hypermedia design principles and is a stepwise method, where the interim
products are the architectural, navigational and interface d
esign. The
CRITON

CASE
tool was engineered specifically to support this design method.

The rest of the paper is structured as following: In section 2 the relevant
research work in the area of design methods and supporting tools is given. In section 3,
an
overview of the three steps in the design process according to CADMOS
-
D is
described, followed by an analysis of the CRITON CASE tool in section 4. In section 5
the evaluation of the tool from its up to date use in courseware projects is presented and
some

thoughts about its future expansion are shared. Finally, section 6 contains some
concluding remarks.

2.

Related Work

There is an increasing work on web
-
based courseware engineering with
emphasis on design methods and corresponding tools [5]. Significant init
iatives have
been set up such as IEEE LTSC [http://ltsc.ieee.org/], Web Engineering [WebE home
page:
http://fistserv.macarthur.uws.edu.au/san/WebEhome/default.htm
] and Prometeu
s
SIG
-
DESIGN [http://prometeus.org/sig/design/index.html]. It is evident, however, that
no well established design methods and tools have appeared as yet.

WBC engineers quite often deal with the design problem, using approaches
from general hypermedia de
sign, on the grounds that a web
-
based courseware is, after
all, a hypermedia application. Although the other WBC development phases, especially
analysis and evaluation, cannot follow methodologies for the development of general
-
purpose hypermedia applicati
on, the objectives of the design phase have been
successfully accomplished by relevant approaches.

A widely used approach of hypermedia design modeling is HDM [8] and its
successor HDM2
[9]
, where emphasis is given in specifying a semantic schema of the
a
pplication before it is developed. HDM provides a rich mechanism for describing the
navigational schema but does not advocate a specific notation for the construction of
abstract interface templates. Even though HDM specifies just a design model and not a
process, it has set the foundations upon which methods and methodologies of
hypermedia design are based.

A successful method for hypermedia design is the Object
-
Oriented Hypermedia
Design Model (OOHDM) [10], which uses object
-
oriented techniques to produc
e a
hypermedia design model and manages to build complex well
-
structured hypermedia
applications.

A methodology that provides step
-
by
-
step hypermedia development is RMM
[11]. RMM offers complete representation of the semantic schema and the navigational
s
chema, follows the traditional E
-
R model to standardize the architectural and
navigational design but gives limited support to the interface design.

Finally some very interesting design approaches have been made during the
following research projects: Mat
ilda (University of Technology, Sydney)
[http://ise.ee.uts.edu.au], GENTLE (Institute for Information Processing and Computer
Supported New Media, Graz
-
Austria) [http://www.iicm.edu], and the Amsterdam
Hypermedia Model (AHM) at CWI, [http://www.cwi.nl/mmp
apers].


4

The main problem in the aforementioned approaches is the lack of sufficient
guidance to the designers in creating the architectural design of the WBC in specific.
They offer a rich set of rules and graphical notation but lack in offering a design p
attern
or even a design framework specific to the needs of WBC. The CADMOS
-
D method is
a variation of the OOHDM, though it differs from the latter in the fact that the object
-
oriented conceptual design is based on an object
-
oriented data model, which acts
as a
design framework for WBC explicitly. This data model gives guidance for analyzing the
WBC into components, i.e. learning resources comprised by specific types of webpages,
such as access pages, content pages, etc.

Concerning the WBC design CASE tools
, some of them are very simple as they
support flowcharting and screen design [12]. Since recently, the phase of web site
implementation is assisted by tools with limited support for design. Having excluded the
simple web page editor, the rest of the web s
ite implementation tools can be classified
into two categories [13]:

1.

Web site editors,
which except from editing web pages provide a mechanism for the
easy creation of a navigational schema as well as for the management of a set of pages
like a file manage
ment system does (e.g. Microsoft FrontPage). Some of these tools also
provide a more structured development (e.g. Fusion Net Objects) by defining a common
look in the form of templates or by providing an elementary navigational design
mechanism.

2.

Web Site B
uilding Environments,
which create hypertext documents at run
-
time
by instantiating templates (e.g. Vignette Story Server, Allaire Cold Fusion, CGI Lua).

These tools are very useful if the development team has already made the architectural
blueprint of t
he WBC, as this design step is not supported by them.

In cases where the need to support a specific design and development
methodology is imperative, customized tools are especially constructed so as to provide
a solid development framework and ease the w
ork of the development team. Some fine
examples of such tools are the OOHDM
-
Web [13], that was engineered to support the
OOHDM described earlier, and the RM
-
CASE [14], a graphical CASE tool, constructed
to support the RMM methodology. Both of these tools,
as well as CRITON, excel the
aforementioned commercial tools in the sense that they all support a method and that
they provide a well
-
substantiated architectural design phase.


The CRITON tool presented in this paper, is designed and developed
especially
to support the CADMOS
-
D design method and has been used to design web
-
based courseware applications. It adopts the data models that this design method
specifies and follows a step
-
by
-
step design procedure. It provides a coherent
environment with a uniform
interface and embraces all three steps of the design method
in a whole.

3.

A brief overview of the design method CADMOS
-
D

CADMOS
-
D is an object oriented design method specifically created for the
needs of web
-
based courseware design. It advocates a stepwise
design process, as shown
in Figure 1: Architectural Design, Navigational Design and Interface Design. The
intermediate products of each step are validated according to guidelines for WBC design
(checking structural, navigational, aesthetics and functional
issues). The whole design
process is considered to be iterative, where in each iteration loop the designs are

5

evaluated and the feedback from the evaluation is used for their improvement, until they
reach the desirable level.

Navigational Schema
Courseware description
descriptino
Navigational Design
OO

architectural

model
Design step
Product
Architectural design
Templates and
pages GUI
Interface Design
Process
Evaluation,
qualitative
review and revisions
Design
Courseware
Design

Figure 1


The three design
steps proposed in CADMOS
-
D

1. Architectural Design



In this step the description of the courseware is transformed
into an architectural design following an object
-
oriented data model and a conceptual
design framework. According to this framework, a WBC is

a mosaic of learning
resources. Each learning resource is a collection of webpages, which can be categorized
into “access pages” and “content pages”. For each type of webpage, the designer must
specify the elements that comprise it, such as media, active
behavior, etc. To serve the
needs of an object
-
oriented notation of the data model, the design method has adopted
the Unified Modeling Language
[http://
www.rational.com/uml
]
, a graphical modeling
language widely a
dopted by the software industry and strongly supported by the Object
Management Group [
http://
www.omg.org
]. Conclusively the architectural schema is a
set of packages, classes and relationships that connect them, which spe
cifies in detail the
WBC structure. In particular, architectural design adopts
use case diagrams

and
class
diagrams

from the UML repository. Figure 2 depicts a class diagram using the UML
semantics that shows some classes of specific pages of contents and
how they all inherit
from the class “CONTENTS PAGE” of the stereotype “WEB PAGE”.


6


Figure 2


Class Diagram of the courseware contents pages

2. Navigational Design



In this step the navigational schema of the WBC is
analytically designed, so that it i
s clearly specified which web pages are inter
-
connected
with hyperlinks. The data model of navigational design contains web pages, single and
bi
-
directional

hyperlinks. The navigational design provides a way of checking the
implementation of all the hyperl
inks in the final product. More importantly it facilitates
the maintenance of the web site, especially when web pages are added or deleted and
hyperlinks to and from them have to be updated. In this way, the well
-
known problem of
dangling links can be avoi
ded. The navigational structures proposed for this kind of
design, are well accepted by many hypermedia design approaches, such as HDM, RMM
and OOHDM. More specifically they are: a)
indices

that provide direct access to every
indexed node,
b) guided tours

which are linear paths across a number of nodes and
c)
indexed guided tours
which combine the two previous structures. The navigation
through the paragraphs of a chapter of an on
-
line book is shown in Figure 3 using
indices, a guided tour and an indexed gu
ided tour.


(a)

(b)

(c)

Figure 3
-

Navigation through the paragraphs of chapter 1 with

a) indices, b) a guided tour, c) an indexed guided tour

3. Interface Design


In this step the interface of the WBC is designed, that is the
content, layout and ‘look a
nd feel’ of the web pages. WBC interface design is ruled by
the principles of the
page metaphor
, a practice taken from multimedia engineering
where it has been extensively used. Page metaphor is used to specify the page
components with graphic symbols and
place them on the screen showing their layout.
Therefore, with the use of graphical semantics, the design depicts the page form just as it
will be implemented. The data model for the interface design contains six kinds of page
components: plain text, multi
media elements, active elements, hyperlinks, frames and
forms. The designs made are actually re
-
usable page templates. For instance, if we
design the page template of one paragraph of an on
-
line book in a WBC, then all the
other paragraphs of the book migh
t have the same look, using the same components with

7

the same layout, have the same frames etc. A page template of a paragraph of our
hypothetical book is shown in Figure 4. During the interface design, except for
designing page components and their layout
, we define certain metadata on them. All
page components from the courseware’s pages are considered
learning objects

and
therefore can have metadata like author details, type or format etc. The definition of
metadata during the design phase is quite impor
tant as it facilitates the management of
the learning objects and the scalability and maintenance of the whole application.

Figure 4
-

Page template for the paragraph 3.3 of the on
-
line instructional book

4.

The CRITON CASE tool

CRITON has been implemented in

Java and can be considered as a 100% pure
Java application, in other words fully cross
-
platform. In order for the design steps to take
place simultaneously and in parallel, the tool adopts the model of Multiple Document
Interface. This model is instantiat
ed by having multiple internal windows, each of which
represents a different design process. CRITON’s technical infrastructure comprises
many of the latest Java APIs, like Swing, 2D Graphics, and the JPEG encoder/decoder.

CRITON generally follows a design

philosophy which is often met in relevant
environments with standard GUI components like menus, menu bars, project trees,
design toolbars, and design frames bearing design windows, as seen in Figure 5. Except
for the standard ‘File’ and ‘Edit’ menus, ther
e is also a ‘Look & Feel’ menu where the
user can alter the general appearance of the application by selecting one of the options
that Java provides. The ‘Build’ menu refers to the tool’s ability to generate a preview of
the courseware.

The project tree is

a structure that represents the WBC design. The nodes of the
first level represent the three design steps of CADMOS
-
D, whereas the nodes of the
following levels represent the products of each step. In particular the second level nodes
are the different de
signs of each step and all other nodes have a special meaning
according to the design in which they belong. For instance the children of a node that
represents a navigational design are its web pages. Finally there are certain operations

8

that can be perfor
med on each node, e.g. it is possible to export the designs represented
by the second level nodes into the JPEG graphical format.

The design toolbars contain all the elements used for the implementation of
each design. There are three different toolbars co
rresponding to each design category
and they are activated according to which design is currently being modified. The
elements in each toolbar belong to the respective data model; e.g. the architectural
design toolbar contains the UML graphical symbols. Th
e design process takes place
with the designer selecting an element from the toolbar, placing it onto the design
windows and then specifying some of its characteristics, such as name, documentation
or other specification data. All the elements specified in

the designs can of course be
dragged and dropped, deleted, cut, copied, pasted, renamed and have certain
specifications viewed and edited. These specifications depend on the semantics of each
element, in accordance to its data model.

The design tool insta
ntiates the three design steps specified by CADMOS
-
D by
having three design processes with three different data models and three different
toolbars. All the designs produced during the design steps described earlier can be
extracted into the JPEG graphical

format. This means that the project deliverables and
reports can be easily enriched with the designs in whatever format they are made (Word
documents, HTML files etc.).



Figure 5


The initial window of CRITON


9

1. Architectural Design


the design takes
place with the use of UML and the object
-
oriented design framework. The toolbar of the architectural design involves the
following elements:


class, package, interface, actor, use case, note, association, dependency, link to note,
aggregation, generalizat
ion, uni
-
directional association and refinement/realization. The
first six elements are object
-
oriented entities, that have specific semantics as defined by
UML and the rest are relationships between them. The specifications of these elements,
according to

their semantics, may include name, stereotype, documentation, attributes,
operations, cardinalities, and roles. CRITON provides some validation concerning the
relationships that are allowed between elements according to the specification of UML.
For examp
le a designer cannot relate a class and a package with an aggregation, as the
modeling language forbids this.

During this design process, the designer attempts to describe the courseware in
an architectural level and make an abstract but complete represen
tation of it. The
designer needs to follow the object
-
oriented design framework from CADMOS
-
D and
analyze the courseware into components, and the components into web pages. All these
web pages must be instantiated in the next design phase, the navigational

design, and
must be connected with hyperlinks.

2. Navigational Design


the design uses the aforementioned navigational structures,
i.e. indices, guided tours and indexed guided tours to describe the way, web pages are
connected with hyperlinks. The toolb
ar of the navigational

design involves the following
elements:


web pages, single hyperlinks and
bi
-
directional

hyperlinks.
B
i
-
directional

hyperlinks
between two pages are equivalent to two single ones between the same pages. The
specifications of the web

pages include name, URL, documentation and page template.
The page name needs to be unique in each design so that no two different pages have the
same name in the web site, even though the same page may appear in multiple designs.
This means that two page
s that have the same name actually refer to the same page. The
URL is the Internet address of the page and can be either a complete URL or a relative
address, for example regarding the starting point of the site. Finally the page template
defines the name
of the template that this page is related to. This is important in order
for the page to have its interface designed according to that template. For example all the
pages that are paragraphs of the on
-
line book will be related to the “book paragraph”
templ
ate. The designer can either specify a new page template or select one from a
scroll
-
down list. The page template field in the page specification is necessary for the
next design step, so every page must be related to a template. In the interface design,
i
nitially each template is designed and after that the design continues for every page that
refers to that template. In the project tree, under each navigational design, we can see all
the web pages of that design as leaves. These leaves can be used to crea
te the designs for
the corresponding web pages. The design process follows a top
-
down tree
-
like flow:
first the designer makes the navigational design for the starting node (probably the home
page of the web site) and then recursively the designs for all t
he pages that the starting
node is connected to.


10

3. Interface

Design


After the navigation to all the web pages has been specified, the
development team needs to design the page templates and interface of the pages
themselves. The interface design in gen
eral takes place with the use of the page
metaphor. The toolbar of the interface design involves the following elements:


plain text, multimedia elements, active elements, hyperlinks, frames and forms. All these
elements can also be considered as part of
the UML semantics. In particular these
elements are defined as UML stereotypes according to the UML extension mechanism,
where stereotypes are classes with some extra semantics. The specification of these
elements includes name, documentation and various m
etadata. The metadata are
different for each modeling element and can suggestively be format, author, size, file
name, run time environment etc. Embedding the metadata into the designs is a very
useful feature, as it allows fast and easy access and modific
ation and a single place of
storage for the metadata. The interface design commences from the design of the page
templates, as these have been specified during the navigational design and carries on
with the interface design of all the pages. When a page’s

template is specified in the
navigational design, a new blank interface design for the template is automatically
created and inserted in the project tree. Also another blank interface design is created for
the page itself and inserted in the project tree
as a child of the former. If the template
already exists then only the second design is generated. When a template design has
finished, then all of its children can import that design and start customizing it.

The production of the courseware preview.
Th
e three design steps of the
design method that CRITON supports, generate three different products: the
architectural design, the navigational schema and the interface design. Based on these
products alone, the development team can proceed with the implemen
tation of the
courseware. In order to close the gap between the design phase and the implementation
phase, CRITON produces the preview of the courseware, which is a set of web pages
inter
-
connected with hyperlinks. In detail the tool creates a web page for

every page
designed during the navigational design and connects it with hyperlinks to the
appropriate pages. The contents of such a page is the name given by the designer which
is also the page’s title, the hyperlinks to other pages and a JPEG image which

corresponds to the interface design of this particular page. For instance the preview of
paragraph 3.3 of the on
-
line book is shown in Figure 6. The preview depicts a virtual
form of the courseware, which is very close to the final implementation and many

useful
conclusions can be derived from it and fed into the design process. When the evaluation
of the preview concludes that the courseware satisfies the learning goals specified during
the analysis phase of the engineering methodology, the implementation

may begin. All
that is left to be done for the implementation is to build the single components of the
page and insert them exactly as they have been specified.



11

Figure 6


HTML page created by the production of the courseware preview for
the paragraph
3.3 of the on
-
line instructional book

5.

Evaluation

CRITON has been used in small
-
scale web
-
based courseware development
projects during the Fall Semester of 1999 for the needs of the undergraduate course
“Software Engineering” and the postgraduate course “In
ternet Publishing” at the
National Technical University of Athens.
The students that took part in the WBC
develo
pment
had a solid computer science background

and some of them
had
already
been
involved in

hypermedia development projects in the pas
t
.

After t
hey had completed
their course projects the development teams filled in an evaluation questionnaire, which
was intended as a source of qualitative feedback. The questions asked in the
questionnaire regarded the tool’s usability, efficiency, adequate docume
ntation material
and level of support to the design method and its three steps. The students were also
asked whether the tool’s capability of exporting the designs in the JPEG format and
generating the courseware preview were helpful in the design process.

Finally the
students were invited to propose enhancements to the tool’s features and capabilities.

The evaluation of the tool under this test bed has given some encouraging
results and some valuable remarks
for
the
future evolution of the tool. The devel
opment
teams have noted that it is quite important to use a uniform environment that embraces
the whole of the design process, which they need to follow. Also the platform
independence has enabled the tool to run in different hardware and operating systems
,
thus alleviating the limitations of hardware or software dependant applications.
Moreover there were some positive comments about the tool’s ability to extract all

12

designs in the JPEG format and therefore making it easy to embed designs in web pages
or o
ther document formats as project deliverables. The trade
-
off, for platform
independence is reduced efficiency, for example when the JPEG encoding is taking
place. That can be fixed by compiling the code in a specific platform, although this
would not agree

with our cross
-
platform philosophy.

Although in this first version of CRITON we attempted to cover as much of the
courseware design process as possible, there are a few additions and improvements that
can be made. The next versions will provide enhancemen
ts in matters like the design of
active elements (CGI Scripts, Javascripts, Java applets) with UML activity diagrams, the
full automation of report
-
generation, and the optimization of the interface data model.
There will also be an enhancement to the cours
eware preview, so that the
implementation can actually take place by editing the automatically generated web
pages of the preview. Finally, the tool will be supported by on
-
line help and the learning
object metadata will be improved so that they comply wit
h well
-
accepted or official
standards (Dublin Core MetaData Element Set [
http://purl.org/dc
/] or IEEE LTSC
Learning Object Metadata, [
http://ltsc.ieee.org/
]). Both the design method CAD
MOS
-
D
and the design tool CRITON will continue to evolve in order to improve the engineering
approach in designing web
-
based courseware.

6.

Concluding Remarks

The Internet and the World Wide Web are expedient and promising means for
substantially assisting hi
gh quality education and training, so as to satisfy the demands
of our times. The software industry and academic institutions are spending a lot of
resources in research and development, in order to create web
-
based courseware of high
pedagogic quality, ta
king advantage of the new learning technologies. However in most
cases the development
teams
use

an ad
-
hoc approach, which does not guarantee end
-
quality. The development of WBC is crucial, as all of these efforts must be based on
sound methodologies, whic
h will guarantee that the final product meets certain quality
criteria. We do not have the luxury of experimenting in expense of the educational or
training process, therefore the use of methodologies is not only useful but also rather
imperative. Moreover
, tools that support methodologies can be extremely important
because they ease and speed up the development process, and finally assure the correct
use of it.

The CASE tool CRITON has been constructed to support a specific design
method, namely CADMOS
-
D a
nd can be used for WBC design. It combines three
design steps in a homogenous environment and it relates these steps making the WBC
design, a consecutive and iterative process. For the architectural design, it uses a
standardized object
-
oriented modeling l
anguage, the UML, whereas for the navigational
design it uses a widely adopted data model. The interface design is based on the page
metaphor, which is also acknowledged between the hypermedia developers and
introduces the specification of learning object
metadata during the design. Finally the
WBC preview is a function that allows the development team to examine a depiction of
the final product and receive valuable feedback from it.

References



13

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M. Driscoll,
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