My teacher is on the network
(Experiences using multimedia communication technologies in distance learning)

Encarna Pastor, David Fernández, Tomás Robles
Dept. Ingeniería de Sistemas Telemáticos
Universidad Politécnica de Madrid
ETSI Telecomunicación, Ciudad Universitaria,
E-28040 Madrid, Spain
Tel: (+34 1) 336 73 28 - Fax: (+34 1) 336 73 33
encarna@dit.upm.es, david@dit.upm.es, robles@dit.upm.es
 

Abstract

The Teleeducación-RDSI project aims to evaluate the adequacy of multimedia communication technologies applied to distance education. For that purpose, graduate and postgraduate courses of the Telecommunication Engineering Faculty were chosen to form the educational scenario for the experimentation of a tele-education system based on mature technologies like Internet, ISDN or H.320 videoconferencing. This paper tries to summarise the experience gained during the project, presenting the technical aspects and infrastructure used, the design of the educational experiences, as well as the evaluation results.
 

1. Introduction

The use of communication technologies and telematics services in education offer a great potential that may contribute to the introduction of new educational paradigms and to enhance the learning process. Nevertheless, it is difficult to find experiences that permit to evaluate, in real conditions, the effects on learning, the limitations that may jeopardise it success, the cost factors that may limit its possible extension or, furthermore, their acceptance by teachers and students.

The Teleeducación-RDSI project, supported by CITAM (Centro de Investigación en Tecnologías y Aplicaciones Multimedia) a research center of the Technical University of Madrid (UPM), aimed to evaluate the adequacy of multimedia communication technologies applied to distance education. The project, recently finished, was not intended as a laboratory experience, but as a real educational experience whose results may enable its extension to a larger scale.

Graduate and postgraduate courses of the Telecommunication Engineering Faculty formed the educational scenario chosen for the experiences. Using video-conference and Internet tools over the public ISDN network, students of the University attended lectures from their homes in real time. They also had the facility to access the contents of the didactic material, interact with others students to work in teams or even contact directly with the teacher for tutoring. Four phases were defined to carry out the experiments, each one providing new technical functionalities and centred around different students/subjects profiles.

This paper summarises the experiences and main results gained in Teleeducación-RDSI project. In the next sections, we focus on the technical aspects and infrastructure used in the project, the design of the educational experiences and on the evaluation results.
 

2. Technical Aspects and Infrastructure

From the technical point of view, the project aimed to evaluate the adequacy of mature multimedia communication technologies applied to distance education. By means of some pilot trials, we tried to gain enough experience to be able to create stable tele-education services using these technologies.

By mature technologies, we understood those technologies that were widely available in the market, and, supposedly, stable enough to let us focus on the educational part of the experiences. In particular, we decided to use:

• ISDN networks, which were at that moment the only widely deployed and affordable network technology for tele-education,
• H.320 Videoconference systems in a multipoint configuration, that is, using client terminals and multipoint units (MCU),
• Internet applications and protocols. Mainly, we used Internet technologies for the asynchronous part of the system: didactic material using HTML, Web servers, electronic mail, news, etc, and
• Personal Computers (PC) with MS-Windows operating system.

Figure 1 shows the global architecture of the system that was set up for the experiences. It is composed of the following elements:

• The communications platform, composed of the public ISDN network and an Ethernet LAN used to interconnect the equipment located at the resources centre, in particular, the lecturer’s terminal, the class recording system and a multimedia information server. An ISDN router allows the access to the server from the students’ terminals using TCP/IP protocol suite. Finally a Multipoint Conference Unit (MCU) is also considered as part of the communication infrastructure, although it is not located at the resources centre.

• The student’s terminal, that offers the required facilities to attend the lectures using a videoconference system over ISDN. It also provides facilities to allow the students the access to the multimedia server with applications such as Email, FTP or WWW. The terminal is a personal computer with the following characteristics:

• Pentium 100 Mhz with 32 Mbytes of memory and a 1 Gbyte hard disk,
• Videoconference multimedia kit: FOCUS-PC (GPT),
• TCP/IP Software with ISDN drivers and standard Internet applications (Chamaleon Netmanage),
• ISDN Connection (BRI),
• Camera, microphone and headphones,
• HP Deskjet Printer, and
• Software: MS-Windows + GPT’s proprietary Shared Applications + MS-Office + other software specific for each course.
  
  
Figures 2 shows a snapshot of a student’s terminal. 

Click here for Picture

Figure 2: Student’s terminal  
• The lecturer’s terminal uses the same configuration in software and hardware as the students’ terminal. In addition, some extra auxiliary equipment for supporting the presentations during the lectures is needed. Figure 3 presents the different document sources the lecturer can show the students through the video channel: an auxiliary computer, to show documents in electronic format; a document camera, useful to show documents not available in electronic format or to be used as a blackboard; a standard video cassette recorder, to show videos; or the teacher’s camera, used to send the video image of the lecturer.

  Figure 3: Sources of video in teacher’s terminal

In addition, the auxiliary computer performs the recording of the lectures in real time. The students are able to access a lectures database (located in the multimedia server) to retrieve either a complete lecture or part of it.

Figures 4 and 5 shows two different views of lecture’s terminal.
 

Click here for Picture

Figure 4: Teacher’s terminal (I)

Click here for Picture

Figure 5: Teacher’s terminal (II)

• The multimedia information server hosts the lectures database and provides access to Internet services such as Email, news and WWW.

• record in real time all the media involved in a session, that is, audio, video, documents and slides, and create all the information necessary to reproduce them;
• upload all the session files to the server and store them in a multimedia database, adding some administrative data and keywords; and
• retrieve the classes from the server in real time, either completely or partially (searching  by time, by slide, by keyword, etc).

3. Pilot Experiences

The Project was structured into four phases corresponding with four different experiences, where each one provided new technical functionalities and new student profiles. Such incremental strategy allowed each experience to benefit from the evaluation results of the previous one, as well as to give time to the developers to finish the specific developments without delaying the whole experience.

The number of students was around 10 in each phase, which offers a compromise between the convenience of having a number of students that allows the generalisation of results and the technical conditions and economical limitations of the project. The students were geographically distributed over the Madrid area.

Table 1 summarises the subject, audience and system functionality of each phase of the project.
 

4. Evaluation

Several aspects have been taken into account to carry out the evaluation of the experiences:

• organizational aspect, with regards to the course organisation and material elaboration, the organisational aspects related to the student terminal, and the training on the system;
• educational aspect, concerning the possibilities the new system offers to improve the traditional education process, taking into account, for example, the subjective acceptance by users, the learning level reached with this system, etc;
• technical, such as video and audio quality, usability or system reliability; and, finally,
• economical, with analysis of the associated costs both for the students and the educational institution.

5. Conclusions and Recommendations

Globally speaking, the system reached a high degree of acceptance between students and teachers. Both of them think it is feasible to attend classes from home or office, although they see some problems due to social interruptions, either at home or at office.

They think the system saves time and travel costs and they find it more suitable for short and optional courses, like the ones imparted in postgraduate programs. For regular courses, they prefer the traditional education, mainly because of the direct contact with other students.
The students appreciated more participation and individual treatment during the experiences, due, of course, to the smaller number of students, but also to the higher interactivity reached with the system.

In general, they had no special problems using the system. After a short introductory session to show how to use it, they were able to manage themselves without support. The case of the teachers was similar, although as we mention below, due to technical instabilities, a technician permanently assisted them.

From the educational point of view, it is important to adapt the didactic material to the system and try to use videos and complementary material, mainly to increase the interactivity and participation. It was found that the participation depends greatly on teachers' attitude, so they have to adopt an exposition-questions modality.

The cooperative applications were highly valued by the students. During the experiences, they made heavy use of them to prepare the exercises proposed by the teacher. However, due to the limitation of these applications to point to point interactions, it was not possible to create workgroups of more than two students.

About the course design, one conclusion is that to maintain the interactivity and create group spirit, the number of students should not be higher than 10. The classes should be given in alternate days in two hours modules, with a short break after the first hour. Besides, it was found necessary to have a Course Coordinator, that is, a person that will be the link between all the parts involved: the teacher, the students, the technicians, the evaluators, etc.

Related to economical aspects, it was found that the use of this system requires an additional effort by teachers, in order to adapt the materials to the peculiarities of this media. This increase in the effort is estimated around 30%, although it is much lower in case of practical or training courses (for example, the PowerPoint course in the second phase) than in theoretical ones.

The cost analysis led to the conclusion that the main cost incurred in the experiences is the one derived from the use of the MCU. The commercial tariffs of this service (~40 ECU per hour and port at that time) were so high that it results profitable to buy an MCU for the resources centre if it is going to be used frequently. The costs derived from the use of ISDN were not high, mainly due to the fact that most of the calls were metropolitan (not long-distance calls). Fortunately, in this project both costs (MCU and ISDN) were assumed by Telefónica, which was one of the project partners.

From the technological point of view, the main conclusion we can reach is that the "mature" technologies chosen for the project were not so stable as we thought at the beginning of the experience. During the different phases of the project we experimented several instabilities, mainly due to the videoconferencing hardware and software in student terminals. The installation and configuration of the equipment was costly in time and effort.

In general, the technology was not imposing a strong limit in the realisation of the educational goals, but the students and teachers pointed that some technical aspect should be improved in the future.

In particular, the quality of images transmitted during multipoint sessions was considered negatively. This fact was caused by the inability of the MCU and the shared applications to support standard T.120 data applications (in fact, the first products conforming to this standard were not available until the last phase of the project). During multipoint sessions, the only way to transmit images (slides, documents, etc) was through the video channel, which led to an appreciable loss of quality and obliged the teachers to use big fonts and consequently reduce the quantity of information in each slide. With the present availability of T.120 products, this fact would not be a problem anymore: the slides could be transmitted through a data channel using a shared application. Besides, the use of shared applications in multipoint sessions, not only in point to point configurations, was found very useful by the students to work in groups.

Another aspect evaluated negatively was the MCU voice switching mechanism. At any time, the MCU tries to switch to the video of the participant speaking louder. But, the students and the teachers considered that the switching time was too long to follow the interactivity of the classes. Besides, there were some other specific problems in the switching algorithm that contributed to distract the attention of students. For example, any time a new participant entered the session, the video was switched to him, distracting the rest of students from what the teacher was saying.

We also faced some ISDN interoperability problems. We discovered that some of the students were not able to connect to the ISDN router to gain Internet access. Further investigation of this problem lead us to discover a subtle peculiarity in the videoconference card ISDN software that, depending on the location of the student (and the ISDN switch model he was connected to), made the connection fail.
Finally, although the system was designed to allow a teacher to use it without needing permanent technical support during the classes, the instabilities of the technology made necessary to have one person permanently available.
 

6. References
 

[1]	T. Robles, D. Fernández, E. Pastor and S. Alamillo. “Using Multimedia Communication Technologies in Distance Learning”. SIGCSE/SIGCUE Conference on Integrating Technology into Computer Science Education. Uppsala, Sweden, June 1997.
[2]	GATE. “Informes de Evaluación de las distintas experiencias”. Internal Deliverables of Teleeducación-RDSI project. 1996-97.
[3]	A. Hernández, D. Fernández, T. Robles, E. Pastor et al. “Proyecto de Teleeducación RDSI del CITAM: Sistema de Grabación y Reproducción de Clases”. Seventh Telecom I+D. Madrid, October 1997.
[4]	CITAM, http://www.etsit.upm.es/asociados/citam
[5]	Teleeducación-RDSI project. http://www.dit.upm.es/~robles/trdsi/trdsi.html

Papers from the 1st LEVERAGE Conference

LEVERAGE home page