The Real Experiment eXecution
Chirico, F. Giudici, A. Sappia and A. M. Scapolla
Courseware development and
delivering represent one of the main topics of present
research activities in the field of computer assisted
learning (CAL). New education technologies have been
driven by the improvement in computer networks
capabilities addressing client-server dynamics, access
mechanism and network services. Furthermore multimedia
authoring tools, WorldWide Web and the programming
paradigm of Java are leading to the creation of new and
effective didactic environments.In this scenario,
particular attention must be paid to the learning design
process, since students can learn better when they are
stimulated by the high level of interactivity and they
can follow a personal way to learn. In this paper a new
approach to Web based courseware development is
presented: the Real Experiment eXecution (REX) approach.
The proposed approach is well suited to the development
of courseware in the field of computer science. Following
the REX approach it is possible to integrate into the
courseware a high degree of interaction since no
simulation activity is performed, but real experiments
are carried out through the execution of operations. The
Java programming paradigm allows the execution, control
and monitoring of these operations. We present a
courseware prototype featuring network services and
protocols, where the students are introduced to the use
of the FTP service. They start a file transfer session
and execute typical commands. The system traces the
generated network traffic and let the students analyse
and understand the results of the ongoing software
The growth of communication resources like Internet and the availability of authoring and distribution tools for computer-based learning products have changed the traditional way to support learning and training activities and to produce and distribute learning materials and publications. The research activities in Computer Based Training (CBT) delivering have taken advantage of computer networks capabilities addressing client-server dynamics, access mechanism and available network services.
The impact of information technology on teaching methods has been driven mainly by:
MM technology, based on the integration of hypertext with images, video, sounds, animations and simulations is very suited to the contemporary educational needs for its intrinsic aspects such as modularity and multisensorial non-linearity .
The MM approach requires that teachers make a great effort in preparing, organising and structuring the courseware. This work supported by progressive validation phases can produce good learning material.
In order to exploit the advantage of MM based teaching methods, it is very important to choose the most effective medium to capture and increase the learner's interest and to combine different media correctly to address the complexity of the real world. Particular attention must be paid to the learning design process, in order to maximise the effectiveness of the new technology and to obtain the most suitable presentation and distribution model .
Students can learn better and more
quickly when they are stimulated by the high level of
interactivity and they can follow a personal way to learn
 . In particular they can customise their
participation to the courseware, establishing the amount
of time to be spent on each topic and individuating their
The WWW represents a powerful medium for its intrinsic deliverability and its larger and larger diffusion through Internet  ; therefore it can play as an effective educational environment and researchers are working to incorporate their pedagogical tools into it. Main advantages of WWW based courseware are:
The increasing complexity of such
educational environment based on the WWW has led to
dedicated frameworks addressed to their assisted
development. Nowadays useful environments are available
to help the courseware author to build and manage an
instructor site with full multimedia data synchronisation
capabilities and communication facilities between
teachers and students  .
Java has been defined by its designers as "a simple, object-oriented, network-savvy, interpreted, robust, secure, architecture neutral, portable, high-performance, multithreaded, dynamic language" . Originally it was mainly introduced to develop distributed and network-centric applications and, in particular, now it exhibits a very high coupling with the WWW technology. More in detail, Java allows the creation of small applications ("applets") that can be easily embedded in the WWW pages, enhancing them with active capabilities.
A number of Java features are highly valuable for the development of WWW based courseware:
These features are valuable for a wide range of applications and they also offer relevant benefits in the development of educational material, for both courseware designers and users:
A courseware must be well structured and guided to capture and maintain the interest of the student: for this reason, the interactive components in a courseware are acquiring more and more importance. The interaction can be carried on in several ways according to the specific educational goal:
We propose a model that deals with real
experiments (REX). In this case, no simulation
activity is performed, but real experiments are carried
on through the execution of sequences of real operations.
The model implements software interfaces capable
of both acting on the real world and collecting results
from it (see Figure 1).
According to the traditional model the learner deals with the courseware and with the real world in two separate moments, and the courseware can just present a picture of the real world. On the opposite, according to the REX model the learner deals directly with the real world, the courseware acting as a tutor. The main goals of the courseware become to guide the execution of the experiment, to give online instructions and information about the involved subjects and to stimulate the partecipation of the student. It is worth noting that all the possible experimental responses cannot be anticipated and covered, but nevertheless the students certainly increase their skill.
A courseware taking advantage from the WWW and MM technologies and the REX approach acts as a "virtual teacher", offering a high level of assistance by means of:
This approach is very convenient in those educational domains where the simulation is a heavy and not exhaustive activity, such as in computer science dealing with operating systems, programming languages and networking topics.
The execution of real experiments requires the creation of interfaces which, in the case of computer science applications, consist of a layer software for the communication between the learners' commands and the target system (operating system, network application, programming language environment). For instance, in the case of a course addressed to the operating system teaching, the layer software must run the command chosen by the student, capture and return the results. The results are then presented in an attractive form together with related virtual teacher's explanations and comments, but it is worth noting that the command is really executed on a real system: this fact leaves the student free to test all the possible choices associated with the command even running into error prone situations like those in the real world. The courseware progress is driven by the captured results.
The development of the interface requires efforts related to the problem analysis and the software implementation. However these costs are comparable to the costs related to the development of simulators or to the inclusion of rich collections of exercises and examples into the courseware.
In general, the REX approach is likely
to succeed in improving courseware effectiveness since it
leads to practice activities diffusion driven by the
virtual teacher and lets the students access real
instruments remotely. It represents a way to share a
resource, concurrently and wherever it is located.
The REX general architecture is depicted in Figure 2. It is based on a traditional WWW courseware model, with the addition of the REX interface. More in detail, this component is made of two parts:
Both sides of the REX interface communicate by means of the Java RMI API.
Thanks to the Java technology, the client computers only need to execute a WWW browser. For this reason a client can be a PC, a workstation or even a machine based on the emerging Network Computer architecture . In particular, this last solution seems appealing to the use in the educational domain thanks to its low costs and administration costs.
At present we are developing a networking courseware prototype which intends to teach network services (FTP, Telnet. ...) and protocols (TCP/IP, SNMP, ARP) using a practical method.
The networking courseware presented is planned to be used in the curricula of electronic engineering in our department. During the "Industrial Electronics" course, the students of the diploma and laurea degree in Electronic Engineering attend lectures on networking themes; we plan so that they can practise with the most widespread network services and protocols in the laboratory.
The courseware will consist of hypertexts and exercises with a high degree of interaction obtained through a guided execution of laboratory experiments.
During exercises and interactive sessions of the courseware students can actually use some network services; the network traffic produced by these activities is then acquired using a dedicated software (Sniffer) and explained to the students. In this way the student can learn the network operational behaviour and the low-level protocols by observing what is actually transmitted on the network.
A pre-release of the courseware is
available: it describes a sketch of the lesson where the
FTP service is explained showing all the protocols
involved during the session. Also a demo version is
available. This demo version illustrates the network
service using a data file which was previously acquired
using the complete version of the courseware. This
simplification is made necessary in order to avoid the
installation of all the modules which make up the
In this paper a new approach for courseware development has been presented; it is addressed mainly to the computer science educational domain; it is based on real experiment execution and, according to the emerging trends in computer based training, it retains the students' interest by means of a high level of interactivity. Given the distributed nature of the courseware and the requirement to interface WWW documents with complex applications, the Java paradigm appears to be the best solution for its implementation.
Future work will concern the add-on of
other applications to complete the existing courseware.
The REX approach is well suited not only for the
explanation of network concepts, but also to monitor
network traffic. It can be addressed to the development
of tools for network problem analysis and resolution.
Future work will be devoted to this direction.
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House Audio Publishing