Combining WWW/Mosaic with Realtime Multimedia Conferencing in Distance Education

Per Einar Dybvik, Norwegian Telecom Research
Håkon W Lie, Norwegian Telecom Research/CERN

Abstract

The paper describes how real-time multimedia conferencing systems is combined with WWW/Mosaic in a seminar offered at the University of Oslo. In order to distribute lectures from one site to another, two electronic classrooms have been established. These offer the functionality of traditional video conferencing systems. In addition, electronic whiteboards running Mosaic are used to present slides during the lectures. The presentations, along with other relevant information, are then automatically available for review by students.

All the communication that takes place between the two classrooms is coded digitally and transmitted over the Supernet, a 34 Mbit/s IP network run by Norwegian Telecom.

Introduction

Video conferencing has not turned out to be as successful as the telephone companies predicted and wished. The reasons for this are many, and [1] reviews both the expectations and the reasons for failure. The use of video conferencing in distance education has mostly been limited to controlled experimental studies by researchers in the field and has not achieved widespread use [2].

In distance education, the video link attempts to substitute the "isochronous" lecture, but has no support for "asynchronous" communication that is also an important part of an educational environment. The asynchronous nature of announcements, handouts and copies of transparencies make them hard to transmit over a video link. Web servers, on the other hand, provide a long-distance asynchronous alternative.

In the experiment described in this paper, we augmented a video conferencing system with an hypertext archive. All lecture presentations and announcements were put into HTML and made available over the Web[3]. We had two main goals for this:

During the lectures, the servers would distribute the presentations to participating sites.
Outside the lectures, students could review the presentations and other information related to the seminar.

The seminar in question was offered at the University of Oslo in the spring of 1994. Labeled "Media Technology", the topics discussed were somewhat relevant to the technological setting.

The University of Oslo has several campuses. Graduate students in computer science are either on the main campus (Blindern) or at a satellite campus one hour's travel away (Kjeller). Generally, classes do not overlap, and students are free to pick and choose from courses at both sites. Due to the geographical distance, however, most students only take advantage of the classes offered at one location. Therefore, the electronic distribution of courses is a stated goal and two electronic classrooms have been established to run experiments. This experimental setup will ideally turn into a facility that allows transparent distribution of courses.

The Electronic Classroom

Two electronic classrooms were used for the seminar [4][4]. They contain the equivalent of traditional two-way video conferencing systems as well as electronic whiteboards. All the communication that takes place between the two classrooms is coded digitally and transmitted over the Supernet.

The Supernet

The Supernet, a 34 Mbit/s IP network run by Norwegian Telecom, has been used to establish real time video conferences between two electronic classrooms. This infrastructure connects all four universities in Norway (Oslo, Trondheim, Bergen, Tromsø) as well as Norwegian Telecom Research (Kjeller). The high capacity of the network and the fact that it employs Internet protocols allows us to integrate video/audio communication with common net resources, such as the Web, into the lectures.

Video/Audio

Each classroom is equipped with a video/audio system and an electronic whiteboard. The audio system consists of microphones placed around in the classrooms, a set of speakers and an echo cancelling system.

The video system consists of two cameras (covering the lecturer and the audience) and a document camera. Video from the remote classroom is displayed on two monitors; one in the front of the room and one in the back. Each room is also equipped with a monitor showing the outgoing video signal. The video is transmitted digitally using a bandwidth of 300-800 Kbit/s with syncronized audio. The audio and video is coded according to the CCITT H.261 compression standard.

The electronic whiteboard

The lecture material and transparencies are presented on a large electronic whiteboard driven by a unix workstation. Physically, the whiteboard is a large semi-transparent glass plate that is being back-projected by a high-resolution video projector. The mouse of the workstation has been replaced with an electronic lightpen on the whiteboard.

The application running on the whiteboard is a modified version of Mosaic for X11. The modifications, courtesy of Vinay Kumar of EIT [6], allows Mosaic clients to remote-control each other. As the lecturer moves forward in the sequence of slides, the corresponding URLs are being transmitted over multicast IP to the other clients which subsequently load the document. Note that this scheme does not scale well; as the number of remote clients grow, a single server will become overloaded.

Several constraints are encountered while using the modified Mosaic. It only sends URLs to the other clients when it retrieves a new document or is doing a reload. Functions like going back in history, scrolling and resizing of windows is not transmitted to the other clients. This makes sense -- the size of the screen, the preferred font and the history may vary between clients -- but turns out to be a constraint in this case.

MBONE

During some lectures the video, audio and whiteboard information was distributed to other sites connected to Internet using MBONE. Students in Stockholm, Tromsø and Trondheim sitting at their workstations have also been receiving video and audio at lesser quality using vat and ivs.

The use of vat and ivs on ordinary workstations didn't turn out to be a success because of poor quality and reliability. But it proved to be a very interesting low-budget alternative compared to expensive classsrooms. Internet is likely to play an important role in the future of disance education due to existing infrastructure and low initial and running costs. In Norway there are around 40 video conferencing studios, but the number of machines connected to the Intenet is 40.000. These machines are not video conferencing studios, but they represent a huge potential for distance education.

The structuring of the presentations

Making the presentations available on the Web requires extra work on the part of the lecturer. Typically, the presentations have to be prepared a day in advance and then massaged into HTML. The extra work required must be contrasted with the benefits: reusability of presentations, access to external data (the seminar compendium [7] was on the Web), and student access to presentations after the lecture. The latter obsoletes paper copies of transparencies.

Making the lecture transparencies electronically available has raised some questions with regard to the structuring of information. The sequential nature of a lecture and the corresponding slides do not exploit the capabilities of hyper-linked structures -- which users expect to find on the Web. The slides had to serve at least three different purposes:

2) for students not attending the lecture

3) for students attending the lecture wanting to review (parts of) the presentation later

The proposed REL attribute to the LINK element of HTML 3 allows the specification of a path of documents through the "Next" and "Previous" values. This would be useful for 1) and 2), while 3) probably is well served by current functionality.

Conclusion

The World-Wide Web represents an information architecture that can be a useful in distance education. By combining the Web with realtime multimedia communication, we are seeing the contours of a rich, distributed, collaborative environment.

Acknowledgements

Our thanks go to Rune Fløisbonn, Bjørn Hestnes, Geir Pedersen, Ronny Nilsen and Morten Sørdal for building and supporting the electronic classrooms.

References

[1] C. Egido, Videoconferencing as a Technology to support Group Work: A Review of its failure, Proceedings of CSCW'88, pp. 13-24, Portland, Oregon, 1988

[2] T. Kristiansen, Five years of research into the use of telecommunications in distance eduaction, Kjeller, Report from Norwegian Telecom Research, 1993

[3] http://www.nta.no/unik/mediateknologi.html

[4] K. Bringsrud, G. Pedersen, The MUNIN Project: Distributed Electronic Classrooms with Large Electronic Whiteboards, Proceedings of the IFIP TC3 International Conference: Teleteaching 93, Trondheim, Norway, 1993

[5] J.W. Bakke, B. Hestnes, H. Martinsen, Distance Education in the Electronic Classroom, Kjeller, Report from Norwegian Telecom Research, 1994

[6] http://www.eit.com/software/mosaic/sh-mosaic.html

[7] http://www.nta.no/telektronikk/4.93.html

Authors

Per Einar Dybvik (pere@nta.no)

Research Scientist and head of the MultiTorg project at Norwegian Telecom Research. The MultiTorg project is working on electronic services for publishing and news distribution. The project collaborates with several publishing and newswire companies in Norway, and is also developing a WWW browser for Windows.

He is also holding a position as a lecturer in Media Technology at the University of Oslo. Per Einar is a graduate from University of Manchester Institute of Science and Technology and Gjøvik Technical School.

Håkon Wium Lie (howcome@info.cern.ch)

Håkon is currently a Scientific Associate with the WWW project at CERN while on leave from Norwegian Telecom Research where he holds a Research Scientist Position. He was co-responsible for the organization of the seminar in Media Technology. Hå holds an MS from Massachusetts Institute of Technology where he worked in the Electronic Publishing group of the MIT Media Lab.