Delivering Hypertext-based Courseware on the World-Wide-Web
David Marshall
(University of Wales, Cardiff, United Kingdom
dave@cs.cf.ac.uk)
Stephen Hurley
(University of Wales, Cardiff, United Kingdom
steve@cm.cf.ac.uk)
Abstract: This paper considers the framework in which
World-Wide-Web based online courseware can be developed. This
framework is illustrated using courseware developed for parallel
computing, C programming, X-Window programming and computer vision. Key Words: Courseware, World-Wide-Web, online, parallel
computing, C programming, computer vision. Categories: H.5 (Information Interfaces and Presentation),
H.1 (Information Systems: Models and Principles), K.3 (Computers and
Education), H.4 (Information Systems Applications).
1 Introduction
The use of computers to provided an integrated environment for
teaching a variety of disciplines has received much attention in
recent years. Indeed many frameworks [3] have been developed for such
purposes. The material provided by such courseware varies greatly from
the provision of lecture notes and lecture support material through
to integrated and interactive tutorial packages. Until recently
courseware has existed as stand alone packages, however with the
advent of the World Wide Web (WWW) [5] on the Internet and accompanying
WWW (hypertext) browsers, such as Netscape and HotJava, the provision
of courseware has taken on a whole new dimension. Many subjects can benefit from the provision of such
courseware. Indeed we are probably fortunate that our chosen
disciplines lend themselves to such methods. For example many methods
that we describe in our courses are interactive and can take on many
states depending on the input data. It is difficult and/or time
consuming to convey all such possibilities in a lecture (or on static
text such as handouts or textbooks). Integrated courseware has an
obvious advantage in presenting such material.
2 Developing Courseware
In this section we aim to summarise our approach to developing courseware on
the WWW. We begin by highlighting the advantages of using the WWW for
courseware. We then broadly describe how the work has been implemented. Page 805
Developing courseware is not merely a matter of preparing a series of
lectures, linking them together and packaging them as a course. A
comprehensive design strategy must also consider how to implement and
manage a course, how to evaluate the materials that are used, and how
to assess the learners. Therefore a systematic approach to the
development of course materials. According to Rowntree [18] the
systems approach should incorporate four basic strands:
- Identify course aims and objectives;
- Develop necessary learning experiences;
- Evaluate the effectiveness of learning experiences; and
- Improve the experiences in the light of evaluation.
In this paper we will concentrate on steps 1 and 2 and show how they
affect courseware development.
3 Identify Course Aims and Objectives
One of the initial, intended goals of our courseware was that it can
be used to support a variety of courses, perhaps including
undergraduate degree programmes in computer science, physics, all
branches of engineering, mathematics and electronics, as well as the
basis of training courses run by computer service departments. The
challenge of designing learning materials for such a diverse group is
to make the materials approachable for all classes of user, and yet
maintain a high degree of specialism, for example, relevant to the
field of parallel computing or computer vision. Designing such materials confronts many well-established and accepted
instructional design principles. The first step in many
instructional design models, is to analyse the learners who will use
the materials. Analysis of even a subset of potential users, however,
would have proved expensive and time-consuming. Therefore a
compromise was made by putting effort into ensuring that the material
would appeal to a broad audience. The characteristics of an instructional medium which interacts with
the learner are the tasks that might influence the learning process
[8]. One concern might be how the choice of hypermedia might affect
learning. Advantages [8] of hypermedia include giving the user control
over the learning process. However disadvantages [9] have cited the
lack of feedback and guidance given. There can be little doubt that the WWW has become the most successful
networked multimedia hypertext based system in recent years. The HTML
language used in WWW documents is extremely simple and yet powerful to
use [6], [7], [10], [11], [16]. These factors highly influenced our
choice of hypermedia implementation systems. We believe that in the
careful design of implementation we have addressed some of the
critiques of multimedia, e.g. feedback Page 806
is provided by parts of our courseware including the automated
assessment of exercises. However several severe restrictions in the current WWW protocol mean
that more advanced hypermedia systems need developing. The recently developed Java programming is significant here because it
makes the WWW truly interactive by incorporating applications that can
be programmed, run live and distributed in a simple, safe and portable
manner. Java also provides an extensible method to handle,
internally, new data type and protocols. Briefly, one can think of
Java as a simplified, safe, and device independent version of C++. How can this influence Courseware on the WWW? The innovations provided by such second generation browsers provide
many interesting possibilities with respect to developing
courseware. Applications can now become truly interactive. Also
Significant advances in incorporating a full range of media have been
made. Distributed hypertext linking over the WWW should also be
improved.
4 Develop Necessary Learning Experiences
The materials originally designed at Cardiff were based on lecture
notes from existing courses. The use of lecture materials is a logical
foundation on which to build a course. On their own, however, lecture
notes are insufficient. User activities during learning are more
important in determining what is learned than the presentation of
instructional material [17]. The aim of evaluating the original
lecture notes was to convert them into more effective learning
materials. To accomplish this, the initial lecture notes in HTML
format were evaluated using models developed from principles of
instructional theory. Evaluation was undertaken at an organisational
level and instructional level. The organisational level focuses on
courseware structure, by means of analysis of users and evaluation of
the learning that has taken place. At the instructional level
evaluation was concerned with the educational effectiveness of unit
content.
4.1 Organisational Unit Design
We initially considered several Instructional Design models and eventually adopted
an established instructional design model: the ASSURE Model developed by
Heinich, Molinda and Russels [4]: A Analyse Learners
S State Objectives
S Select Media and Materials
U Utilise Media and Materials
Page 807
R Require Learner Participation
E Evaluate and Revise
The use of the ASSURE modelq for initial evaluation allows for the
systematic alteration of existing course material (lecture notes,
etc.) by focusing on learning issues which might not have been
addressed in the original lecture notes, such as the potentially
diverse characteristics and experiences of users. For example, this
led in many cases to the alteration of language to suit a more general
audience.
4.2 Instructional Unit Design
The instructional level of evaluation is concerned with increasing the
educational potential of each unit. This evaluation framework was
adapted from Gagné's sequence of Instructional Events [2], which are based on
the hypothesised sequence of internal stages of information processing
derived from studies of cognitive processes. The use of Gagné`s events of instruction as an evaluation tool led to
further changes in the development of a suitable model and particular
changes in courseware content. For example instructional event three,
stimulating recall of prerequisite learning, led to the insertion of
additional references to other units. Utilisation of the ASSURE model and Gagné's Instructional Events is
not intended to provide a prescriptive design model. Rather, it
provides a framework based on sound instructional strategies within
which it is possible for individual course designers to develop a
dialogue about design strategies. The tools provide a common ground
for collaboration.
4.3 Utilise Media and Materials
The following sections contain illustrations of two implementations of
hypermedia incorporated into the courseware.
4.3.1 Using Mpeg Movies to Animate Algorithms
The mpeg movie format is the most popular storage format for image
sequences on the WWW. Most browsers are able to support such a
format. Animation of algorithms is clearly a useful learning tool[11]. Illustrations can be
compiled off-line and simply stored and played back on request. Our
courseware has extensive use of such a facility. Example uses of mpeg
movies are given in Section 6. Page 808
4.3.2 Using Forms and Scripts to Achieve User Interaction
User interaction in hypermedia environments is often limited to
selecting options with a mouse. In such an environment, the learner is
merely presented with the information, having few opportunities to
interact with the material. The HTML language however provides
opportunities to develop additional types of participation. Consider
the following example: Simulated annealing is a non-trivial multiprocess whereby the loads on
a processor network may be minimised (usually not
optimally). Observation of students has shown that involvement in the
implementation of this algorithm improves their comprehension of
it. The courseware implements a simulation which allows the user to
execute the algorithm on a simple linear processor network. The user
is able to see the results of the algorithm by means of a graph which
plots the load on the network against the ``work'' done by the
algorithm. To enhance understanding the user can adjust the various
parameters which affect the algorithm's performance. The algorithm can
be rerun with different parameters, and the new results are plotted on
the same graph with the previous results. This allows the user to
compare and contrast performances, and understand how the parameters
affect the algorithm, and consequently more fully understand how the
algorithm works. The demonstration of simulated annealing is possible because HTML
allows links to executable programs and scripts. As long as a suitable
HTML document is produced by the program(s) called, the user is
unaware of all the ``behind-the-scenes'' operations that are taking
place. The main feature of HTML which allows user interaction is the HTML
form, which enables user input to be passed to the programs which
produce the HTML documents. We have also made extensive use of forms
and scripts to provide comprehensive search facilities within our
courses[10], [11], [16]. This is a popular tool since it
provides an easy means to access parts of the course in a similar
manner to the index of a book. Example uses of forms will be provided
in Sections 6 and 7 which deal with specific implementations of
courseware.
4.3.3 Using Java for true algorithm animation and user interaction
The recent innovations provide by the Java language and its ability to
integrate runnable applications live over the WWW provide many
exciting possibilities. The first version of the courseware[10] was implemented before the advent of HotJava. All
the background processing performed in the initial versions live was
achieved by running (Perl) scripts and C programs with the resulting
data and images mapped back to the HTML browser (Section 4.3.2). The
second version of some of the courseware has the processing routines
rewritten, where appropriate, using Java applets for complete user
interaction. This was not a major problem as the routines were
available in C and easily modified for the (C++ lookalike) Java
language. Examples of the courseware featuring Java Page 809
applets are given in Sections 7 and 8.
5 Overview of Current Implementations
The courseware we have implemented currently integrates the following:
- Course notes, program listings, reading lists, class information etc.
- Algorithm animations e.g. interactive image processing over the WWW.
- Links to run programs and view program output.
- Exercises and solutions.
- Links to other sources of information on the WWW.
The courseware follows the basic framework laid out above in that major
topics are basically treated as chapters of a hypertext book. Sub-topics are
sections and subsections of each chapter. Many examples of results are given
in the form of image sequences. These are simply hypertext links to images.
One other development is that live data processing can be performed on the
WWW. This has been achieved by spawning programs, Java applets or scripts
in manners described previously [10], [11], [16].
6 Parallel Computing Courseware
The material produced was developed with the aim of aiding the teaching of
high performance computing throughout the university sector in the UK. The
course consists of four books:
- A Classification Scheme for Parallel Computers. This book describes
Flynn's classification scheme for parallel computers.
- Interprocessor Communications. This book describes two methods by
individual processors within a parallel computer can send messages to
other processors within the same machine.
- Load Balancing and Task Scheduling. This book describes two methods
by which an algorithm written for a parallel computer can achieve high
efficiency by ensuring that all the processors are performing equal
amounts of work.
- Parallel Algorithms. This book describes the writing of algorithms
for parallel computers.
Page 810
To describe the essential features of the parallel computing
courseware we will describe the book on Interprocessor
Communications. Initially, after selecting this section from the
four books mentioned above the user is presented with the page given
in Figure 1.
Figure 1: Interprocessor Communication Front PageThis page (Figure 1) provides the following high-level information to
the user:
- The top left area of the page outlines the contents of the
book. This provides information not only on the titles of the book's
chapters but also provides a means of directly accessing the chapters
of interest (by clicking on its title) e.g. clicking on Shared Memory
takes the user directly to this section in the book. The contents list
also indicates the current position of the user in the book.
- In the bottom left part of the page, navigational aids are
provided (i) to move around the information contained in particular
books and (ii) to allow movement between different books. The
various options are illustrated in Figure 2
- The right part of the page usually contains three subsections:
Overall, the courseware
has been developed and constructed such that the user (i.e. student)
is provided with concise relevant information and is not overwhelmed
with too much detail per page. Navigational aids are constructed so Page 812
Figure 3: Background Information: Parallel Computing that the students can search the complete course and individual books
relatively easily. The general principles used in developing the
parallel computing courseware can be applied to any subject areas.
7 C Programming
The basic design methodology of Section 5 has been extended in the
following way for the C programming courseware [1], [11], [13], [14],
[15], [16]:
- A form based key word search CGI has been implemented (Figs. 5 and 6).
- At the end of each chapter an exercises section was provided which adhered
to the provision of exercises in the lecture course.
- Links for each exercise were provided to the Ceilidh automatic program
marking systems ([19]) to provide to the following :
- - Model solutions to exercises.
- - Interface to Ceilidh's automatic program marking module (Figs. 7, 8
and 9).
- Links so that listings of programs can be obtained at relevant points in
the notes.
- Interactive Java Applets to illustrate key data structure concepts (e.g.
Linked Lists and Trees) have been implemented (Figs. 10, 11, 12 and 13).
- Links to alternative notes around the WWW.
Page 813
Figure 4: 4D Hypercube Description - Links to local on-line information about using the workstation, C
compilers, UNIX programming and on-line manuals.
In order that familiar information be easily accessible we have
implemented a key word search facility (Figure 5). This uses the HTML
form interface and calls custom written PERL scripts to implement to
search of specified sections of the text. The output of a search is a
HTML page containing links to documents in which the key was
found. Also, within each document, pointers are placed (Figure 6) to
indicate the location of the key. This continuing the hypertext text
book analogy would correspond to the index of a book. The interface to the Ceilidh Program Assessment system [19] provides
are very informative feedback loop for students learning nearly all
aspects of C programming. Students submit exercises via a html form
(Figs. 7 and 8) and receive a detailed breakdown of their submission
(Fig 9). One recent addition to the C courseware is the use of interactive Java
applets to illustrate key data structure or algorithm design. Two
examples are Linked Lists and Binary Tree sorts. In both applets the
user can assemble an initial structure (Figs. 10 and 12) following
this the user can interact to add, delete, etc. values. At each level
of interaction the applet animates the process and highlights portions
of pseudo-code displayed on the screen (Figs. 11 and 13). Page 814
Figure 5: Form Based Key Word SearchPage 815
Figure 6: Result of Key Word Search
Figure 7: Program Assessment InterfacePage 816
Figure 8: Submitting an Exercise Interface
Figure 9: Program Assessment FeedbackPage 817
Figure 10: Linked List Java AppletPage 818
Figure 11: Java Linked List InsertionPage 819
Figure 12: Java Binary Tree Sort AppletPage 820
Figure 13: Java Binary Tree InsertionPage 821
8 Other Courseware
In this section we highlight important aspects of two other courses we
have developed -- X Windows and Computer Vision. The basic design
and development of the courses is as has been outlined throughout this
paper. However both these disciplines involve a high degree of
interaction in understanding key concepts. The interactive facilities provided by various facets of our
courseware is clearly useful in giving a clear understanding and
exploration of these concepts. X Windows The X Windows courseware features a novel Java applet that allows the
assembly of X Windows interfaces graphically within the
courseware. The user simply submits the WYSWIG appearance of the
interface to produce X Window C code that can be downloaded and
compiled as actual X Window program code. The X Window Builder
Interface is illustrated in Figs. 14 and 15.
Figure 14: X Window Builder Applet Computer Vision Many issues in Computer Vision or Image Processing involve highly interac- Page 822
Figure 15: X Window Source CodePage 823
tive choice of parameters and values, especially when experimenting
with new images to process. Experimenting with values and receiving
immediate visual feedback is clearly a very useful learning tool in
this area. Our Computer Vision courseware make extensive use of Java
applets to facilitate such interaction. Examples using thresholding
(a simple image processing task where an image is binarised -- divided
into area that are either black or white -- based upon pixel values
within the image being above or below a given threshold value) are
illustrated in Figs. 16 and 17.
Figure 16: Initial Image Display
9 Response to Courseware
The adoption of the WWW as a courseware provider has proved to be
successful. It provides a flexible way to provide a variety of
presentation methods. Since programs and/or scripts can be run from a
server there is little that cannot be provided on-line. We have been able to demonstrate that this approach is possible and
further more does not pose any trouble to implement given a good
knowledge of UNIX programming. Page 824
Figure 17: Thresholded ImagePage 825
Previous problems of running programs and applications across the WWW
appear to have been resolved with the advent of Java. This has had significant
advantages in terms of implementation and speed up due to being able to handle
data internally in an applet. Student response to the courseware has also been positive. The
courseware has been available for the whole of the vision systems
course. Student response to this was good. This was evident from the
use it received during the course and from student responses --- both
informal verbal comments and from end of course questionnaires. Very
little difficulty was experienced in using the system. It also has
proven popular as a revision aid during examination times. The layout
in the form of a hypertext book appears to be to favoured format for
students to browse through topics and the provision of advanced key
word searches aids revision and general course work preparation. The
provision of source code and algorithms for image processing routines,
runnable versions delivering images as output and having both
available for simultaneous study was warmly welcomed. Formal student
projects and studies have also been set up with the aims of gauging
student response and also to evaluate our work with relation to other
WWW courseware. The results of these surveys have been presented in
[12], [13]
10 Conclusions
Using a structured framework for the design of online courseware
produces teaching materials which are educationally sound and easily
extendable. In addition to this the materials are easy to develop and
are popular with users.
11 Using Our Courseware
Our courseware is freely accessible over the WWW (URL:
http://www.cm.cf.ac.uk/Teaching/). We welcome comments and input on
the courseware developed so far.
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