ELSEVIER Computer Networks and ISDN Systems 29 (1997) 1787- 1797

Use of instructional material in universal teleteaching environments

Robert Grebner * Universit?, o~Erlangen-Nuremberg, Lange Gasse. D-90403 Nuremberg, Germany

Received 1 July 1997

Abstract

This article classifies teaching media, which are used in teleteaching and traditional forms of instruction. A definition for flexible teleteaching solutions is given and a list of requirements for universal teleteaching environments is named. Criteria such as variability, quality, scalability and cost effectiveness are considered in the light of a flexible teleteaching solution. In addition an environment constructed with these criteria in mind is presented, as it is currently being realised under the auspices of the ‘Multimedia Teleteaching-MMTT’ project of the DFN-Verein (Association for Promoting a German Research Network) at the department of information systems at the University of Erlangen-Nuremberg. While developing the concept particular consideration has been attached to the high quality which is to be expected of the various teaching media. Experiences from this and the preceding project ‘Multimedia based decentralisation of interdisciplinary teaching’, which was also sponsored by the DFN-Verein, are to prove that the integration of conventional and electronic teaching media can, under certain circumstances, fulfil all the outlined criteria. The article closes with an overview of a possible future teleteaching environment in cyberspace and the ensuing renaissance of conventional teaching materials. 0 1997 Elsevier Science B.V.

Keywords: Teleteaching; Telelearning; Teaching media: Teleteaching environments; Teleteaching media channels: Teleteaching workspaces

1. Flexible teleteaching

1. I. The terms teleteaching and telelearning

Telecommunication technology, such as the tele- phone or conferencing systems, provide the means for distance education, where learner and instructor can be spatially apart and can teach and learn at different times. Moore refers to this context as a learner-instructor-interaction, which is regarded as

* Email: grebner@wi2.wiso.uni-erlangen.de

essential by many lecturers, and highly desirable by many learners [6]. Teleteaching and teleleaming can be described in the following way:

Teleteaching is concerned with the requirements demanded of the lecturer and the problems involved with this new teaching method, whereas telelearning deals with the requirements necessary for the student to access teaching materials or synchronously inter- act with the lecturer or other students (leamer-in- structor or learner-learner interaction). This subdivi- sion of teleleaming into synchronous and asyn- chronous also applies to teleteaching, where the lec- turer on the one hand has to prepare the lecture

0169-7552/97/$17.00 0 1997 Elsevier Science B.V. All rights reserved. PII SO169-7552(97)00097-4

I788 R. Grebner/Computer Networks and ISDN Systems 29 (1997) 1787-1797

content and has to decide on the use of different kinds of learning media. On the other hand, he or she has to synchronously interact with the remote partici- pants using all the available teaching materials and techniques.

The following paragraphs are primarily concerned with the synchronous form of teleteaching, which by technical necessity were not included in the tradi- tional definition of distance education as given by Peters [7].

1.2. Dqfinition qfflexible teleteaching

The term flexible distance learning is defined by Brand as a form in which the learner can decide by him or herself what to learn (he or she can define, what learning represents), when to learn (time, dura- tion, frequency), how to learn (models of learning, learning media) and where to learn (location) [2]. Analogous to flexible distance learning, with flexible teleteaching the teacher can determine * where to teach (location) * how to teach (selection of models and learning

media)

as described later in the article, in educational institu- tions can lead to substantial savings and improve- ments in cost-effectiveness without compromising the quality of instruction. A university could for instance reduce the number of lecture theatres that have to be maintained if students were able to partic- ipate in university lectures from home. Savings in staff education programs within corporations are re- alised through reduction in travel time and cost. In addition, the synchronous and widespread introduc- tion of new or re-engineered business processes or technologies within a spatially distributed company are facilitated by the use of flexible teleteaching techniques.

2. Media used in education

+ when to teach (frequency, time, duration) - whom to teach (participating students) and . what to teach (what information about a presented

subject is given to the students). Depending on the learning environment, this flex-

ibility may be curtailed for instance by curricula, timetables and other regulations.

Each individual teaching media contributes to the subject of the lecture; each offers the student other advantages or requires other skills, not one of them can achieve everything alone [3]. This insight and the requirement for multiple channels of reception, as postulated by Vester [8], is satisfied by a large variety of teaching media. With the diminishing utilisation of conventional teaching media (e.g., handouts or overhead transparencies) and increasing use of multimedia presentations in lectures, these can subsequently be made available easily and quickly for teleteaching purposes. However, in a teleteaching environment it is essential that all teaching media retain their pedagogical value.

1.3. Ben&s ,for educational institutions

There are many situations where direct contact between instructor and learners can lead to financial and time savings as well as an improved knowledge transfer. The former refers to a situation where ex- pert knowledge is presented to users and interested parities, using teleteaching methods rather than writ- ten documents which would require more prepara- tion time and effort for the expert to produce and which may not efficiently communicate the essential information. The possibility of interaction leads to a more learner centred instruction, which results in a more efficient knowledge transfer and a shorter learning process.

2.1. Groups of conventional and electronic teaching media

Conventional teaching media can be subdivided into five groups. The first group consists of unmedi- ated speech, gestures and social interaction. The second contains further audible media, such as sounds and music, the third holds printed media, namely books, lecture notes and assignment sheets. The fourth media group includes blackboard and trans- parencies, which are used in lessons to present text and graphics. Real materials or living creatures, rep- resenting the fifth group, are very seldom used media often utilised only in primary schools.

The application of flexible teleteaching methods, The use of audio and video material can help

R. Grebner/ Computer Networks and ISDN Systems 29 (1997) 1787-I 797 1789

illustrate and explain, through authentic sounds and images, certain complex subjects which otherwise would be too difficult or exhaustive to explain. Computer generated multimedia content provides the advantage, that it can be prepared before a lesson and interactively annotated or refined during the presentation by the teacher and the students. Hyper- links cannot only be used to enrich a subject through additional, supporting or related information but also provide the means for fast and easy navigation be- tween different sources and types of information. In addition, this kind of media allows for easy editing, reproduction and repeated use of teaching material.

2.2. LeL1el.s of teaching media

The subdivision of teaching media into three lev- els furthers the understanding of their application in teleteaching environments. The first level, which also forms the base of this model, consist of knowl- edge and information, present for example as speech, text, graphics or gestures. The second level includes all types of storage media, or devices used to illus- trate the taught context, such as computer models, blackboard illustrations, handouts or audio/video recordings. The third level comprises all tools which are used to distribute the stored information in a teleteaching environment to remote students.

.

Methods for conveying information (first level teaching media)

Information concerning the taught subject can be conveyed to the learner using speech, ges- ture, social contact, text, images, sound/music, moving images and (living) objects. These methods for conveying information are referred to as first level teaching media, since they are perceived through the sense of vision, smell/taste, hearing and touch.

Storage and presentation systems of first level media (second level teaching media)

First level teaching media can be stored and presented using a variety of technical systems. Gliickel refers to such devices as a teaching aides [3]. In the graph below blackboard, over- head projector, handouts, audio-video record- ings, computer applications and models of real objects are part of this type of medium. The instructor is also part of this category, since he or she also represents a source and presenter of first level media. However the instructor has the special role of co-ordinating the use of all other devices in this category.

Systems for distributing stored information (third level teaching media)

In a teleteaching environment several distribu- tion media are used, among others video con-

document server

applica- tion tool

Virtual Reality

- suppork completely . . . . . supports partially ~ substitutes

Fig. 1. Three levels of teaching media.

1790 R. Grebner/ Computer Networks and ISDN Systems 29 (1997) 1787- 1797

ferencing systems, whiteboard applications, document servers, audio/video servers, shared-application systems and networked vir- tual reality systems.

Fig. 1 shows the three levels of teaching media. Second level media are related to first and third level media in three ways. The relationship ‘supports com- pletely’ means that a higher level medium can store/distribute the information contained within a lower level medium with no loss of educational value. The relationship ‘supports partially’ implies that the distribution of a medium cannot take place without the loss of relevant information. In the case of a video conferencing system, social contact cannot be conveyed by the medium. The third type of dependence, namely ‘substitutes’, infers that a medium on one level is made redundant through a higher level medium, acting as a substitution for the lower level medium, for example if a whiteboard tool is used instead of the overhead or blackboard. The requirements which have to be met when realis- ing teleteaching sessions are touched upon in Section 3. The fact that the instructor cannot be substituted, even in virtual reality systems, which are capable of substituting all other second level teaching media, is a prominent feature in the network of interactions shown in Fig. I.

3. Demands upon universal teleteaching environ- ments

Teleteaching environments consist of rooms or workplaces which are equipped with special multi- media computers and A/V periphery, networks which interconnect these computers and communica- tion software which handle the transfer of teaching media. These can be regarded as universal if they support flexible teleteaching, can be used for multi- ple purposes and are scalable with regard to all relevant resources. Furthermore quality and cost ef- fectiveness criteria should be closely monitored to ensure the acceptance by the provider and user of teleteaching environments. * Flexibility

Teleteaching environments are regarded as flexible if the location from which instruction is to take place, for example an office at home

or at work or a lecture theatre (where), pro- vides the instructor with the freedom to use any teaching media he or she wishes (how). There must also be a sufficient number of such teleteaching theatres/offices to ensure that an instructor does not have to wait to use such an installation (temporal flexibility; when), and there have to be enough workspaces for the potential participants (whom). The selection of teaching materials that is made for one particu- lar subject has no effect on the organisation of teleteaching environments.

Variability An office/lecture theatre equipped for flexible teleteaching should also be usable - for non-teleteaching lectures and - as a remote lecture theatre for students fol- lowing the instruction by a remote lecturer. To realise this variable use of the office/lec- ture theatre the software and A/V hardware for example need to be easily configurable.

Scalability On the one hand teleteaching environments have to meet the high quality standards that are necessary to display all types of teaching media without loss of didactic effect. The transmis- sion of speech and gestures without loss be- tween instructor and learner is in many cases very important (cf. Section 2.1). On the other hand, for reasons of cost effec- tiveness and flexibility in terms of location. one has to attempt to use as much of the present infrastructure for teleteaching purposes as pos- sible, for example by integrating PCs via ISDN into teleteaching environments. The latter could be easily realised through the public ISDN network, however the bandwidth limitation of 64 and 128 Kbps respectively makes it not suitable for high quality video transmissions (see 141). Teleteaching environments should be capable of supporting various technologies and should be adaptable to different bandwidths that are available.

Quality First, teleteaching environments should be able to utilise the available resources to display the teaching media in the best possible quality. Second. the technical surroundings (hard and

R. Grebner/ Computer Networks and ISDN Systems 29 (1997) 1787-I 797

software) need to retain a high degree of stabil- ity, to ensure an uninterrupted communication or interaction between the participating individ- uals, which also leads to a widespread accep- tance.

Cost effectiveness When operating teleteaching environments one needs to ensure that the often large investment is amortised. To realise this aim a high degree of automation can cut back on personnel cost, but it is also necessary that individual rooms and workplaces are operating at the highest possible capacity. This especially holds for in- vestment intensive rooms, such as teleteaching lecture theatres and seminar rooms.

The optimisation of one criteria for a universal teleteaching environment cannot be made without taking into consideration other criteria, as these are interrelated. The better the scalability, the lower the overall quality or the cost effectiveness. A more flexible system for instance may have unfavourable scalability properties. If for example teaching media are used which require several video channels, these can no longer be transmitted in acceptable quality using ISDN lines. The different requirements hence make an overall optimum impossible. For each indi- vidual project or use of this technology one has to assess the weighing of different criteria and devise a strategy specifically suited for the instance.

4. Architecture of teleteaching environments

4. I. Teaching media charmels

From a general point of view, teleteaching envi- ronments must consist of at least two separate places or workspaces, at each of which participants can interact and which are connected by channels for transporting first level teaching media (see Fig. 2). As a rule teaching media channels connect all in- volved teleteaching workspaces and are synchronised in order to present different kind of media like speech and gesture in a synchronous manner. In addition they satisfy real-time demands to guarantee uninterrupted flow of time critical media streams (audio-video). Short transportation time of data is necessary for instance to realise discussions between

teaching media channels

teleteaching workspaces

Fig. 2. Architecture of teleteaching environments

participants without disturbing waiting periods. In other situations, it is sufficient that signals slowly pass through a media channel. If for example a film from a video tape has to be transported to remote locations, there is no need of true real time condi- tions. A broken video stream can be put together at the destination and played back with some delay.

Teaching media channels can support one-way and multiple-way transportations, where the latter can be subdivided into full and half duplex channels. With a one-way channel a teaching media can be sent from one teleteaching workspace to another. Half duplex means. that all connected workspaces can send on the same channel, but always at separate times. Full duplex channels are able to transport a distinct medium, for instance speech, from every workspace to all other places simultaneously.

The following classification of teleteaching media channels discusses how one can differentiate whether or not transportation of media can be carried out continuously by the channels. Speech, sound and motion pictures need a continuous transportation without interrupting the use of a channel, whereas for text and still video this condition has not to be presupposed.

The different ways of transportation can be ap- plied to satisfy different requirements of teleteaching communication within teleteaching environments.

One-way: Transmission of teaching material pre- sented by the teacher, which frequently changes (for instance transparencies and slides).

1792. R. Grebner/ Computer Networks and ISDN Systems 29 (1997) 1787-1797

Half duplex: Transmission of media, which can also come from learners’ locations and only one medium per time can be picked up by the partici- pants (such as the gesture of the speaker).

Full duplex: Transmission of media, which are used and presented simultaneously, such as speech of multiple speakers in a discussion.

If many teleteaching media channels are used in one session, the problem of selection of the right channels can emerge. Normally the teacher should pay attention, that there is no overload by media channels. But one common problem is for instance the selection of the video channel of that person who is actually speaking. if there are multiple teleteaching workspaces and one separate video channel from each location. The selection problem can be solved by one central participant place or by each individual place. To distinguish different kinds of workspaces, that one, at which the teacher stays, is called the local or central space whereas the others are remote ones. Nevertheless the local workspace can also cover learners or students.

In local spaces teaching media is assigned to a corresponding media channel, in order to transport it to remote recipients. Arrived there, an adequate rep- resentation of the media has to be arranged. To cover all possible types of first, second and third level media, four different kinds of media transportation channels are required.

Audio channel: speech, sound, music (also recorded audio, e.g. on an audio server or tape)

Video channel: gesture, motion pictures, black- board, transparencies. models and real objects (also recorded ones, e.g. on a video server or tape)

RGB channel: the output of computer applications by RGB channels, which deliver to the remote partic- ipants the same signal as sent to a local monitor or projector

Data channel: computer conferencing systems. document server and virtual reality

4.2. Teleteaching workspaces

In the next sections, teleteaching locations of different size are distinguished which represent par- ticipant locations and which have been realised in the project ‘Multimedia Teleteaching (MMTT)’ of

the DEN-Verein. When designing the locations, one has to consider . Flexibility with regard to the use of different

teaching media. * Quality of both the presented and transportation

of media, considering budget constraints. * Variability. * Cost effectiveness.

This criteria have been established as very impor- tant during the project of interactively distributing presentations, exercise sessions and lectures. Scala- bility was not determined as a critical factor. One problem of this list of criteria is, that quality de- mands are hindering in a way flexibility concerning the free choice of location as well as scalability. The compromise that was found in Nuremberg-Erlangen is, that learners can not participate in lessons from home but have to visit the various teleteaching loca- tions, spread over Nuremberg and Erlangen [I]. The reason for this is that high quality authorities are currently very expensive to equip.

Future development in price and technology let it foresee, that this restriction could be lifted soon, when multi-point connections between different kinds of hardware platforms and broadband networks to the home are possible and payable. An useful subdi- vision of teleteaching workspaces can be done by the question how much participants they are able to hold. An amount up to three persons can be placed well before one single teleteaching workstation, that provides some special multimedia devices. A teleteaching room is ideal for groups of up to 30 people and a substantially equipped teleteaching the- atre can easily hold several hundred learners, follow- ing the explanations of the lecturer in person. The most obvious difference between the various loca- tions are the number of connected teaching media channels and supported projectors as well as A/V peripherals.

4.2.1. Teleteaching lecture theatre Teleteaching lecture theatres within a universal

teleteaching environment essentially consists of the five main parts controlling platform. teleteaching user terminal, projectors with appropriate control units, A/V periphery and second as well as third level teaching media.

R. Grebner/ Computer Networks and ISDN Systems 29 (1997) 1787-l 797 1793

projection of remote students and overhead projection of transparencies computer presentations

/\ / .“, backbone of the University of

Erlangen-Nuremberg

in the lecture hall

- - I . -

video mixer mixer / control centre

/

I ATM switch

audio (analogue) --m-m-)

video (PAUNTSC) . . . . . . . . *

video (RGB)

I.... *

serial (RS23.2) +

Fig. 3. Teleteaching lecture theatre.

Fig. 3 illustrates the construction of a teleteaching theatre realised at the faculty of business administra- tion of the University of Erlangen-Nuremberg, which supports all teaching media of level two and most of level three. Speech and sound of the theatre are captured by various microphones and transported to the control centre, which provides the connection to other teleteaching workspaces via media channels. Gesture and other changeable picture media (e.g., writing on the black board) are filmed by multiple video cameras, which are mounted in different places of the theatre and which are remote controllable by the control centre. After the video stream is cut and revised, it is also sent over a media channel.

Unlike conventional media (e.g., black board, overhead) electronic teaching media (e.g., computer animation) must be projected with additional device at the local workspace. The transportation to remote workspaces happens just as described above.

4.2. I. I. Teleteaching user terminal The teleteaching user terminal (see Fig. 4) is the

most important part of the teleteaching workspace for the teacher or trainer. It can completely substitute overhead transparencies without loss of any func- tionality. The teacher can write on a paper or also on

a transparency laying on top of the terminal on a defined place, which is filmed by a scan camera. The motion picture of the scanned field is shown locally and transported to remote workspaces and each edit- ing made by the teacher can be followed by all participants. To control the scan fields more easily, a monitor is build into the terminal. Applying this method, the teacher must be aware of the resolution of the camera and write letters or paint pictures large enough. This means no new restriction for the teacher, because writing to the black board or over- head transparencies also has to take into account the size of writings because of participants sitting in the back rows.

yboard and mouse of PC

Fig. 4. Teleteaching user terminal

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The main application of the teleteaching terminal are presentations via a multimedia computer, which provides a touch screen. With a special pen the teacher can write and paint as he or she usual does on paper. Using this procedure everything really runs electronically. The editing on the screen is displayed by a local projector and transferred to remote workspaces via a media channel. The teacher can prepare lessons with a computer, build in computer animation and use hyperlink techniques. Annotations and material developed during a lesson can be saved and reused or edited at a later time.

In many cases teachers or lecturers bring their own notebook with them and connect it to the teach- ing terminal. The terminal then treats the notebook as the build in multimedia PC.

For a comfortable communication between the teacher and remote participants the teaching terminal has a centred camera, filming the teacher, when he or she works in front of the terminal, and in addition provides a screen to monitor remote participants, which actually make a contribution. A further moni- tor with touch screen serves as a control panel for conferencing tools etc.

4.2.1.2. A / V peripherals For the automatic tracking of a teacher or lecturer,

special cameras with this functionality are used. Several camera positions are needed to cover all potential locations of the teacher in the lecture the- atre (black board, overhead, etc.). For the transmis- sion of speaking participants, it must be possible to film all theatre seats.

The best but most expensive solution for very good audio quality would be the installation of a microphone for every seat in the lecture theatre. A good quality can also be achieved with ceiling- mounted microphones.

4.2. I .3. Projectors To present both teaching material and pictures as

well as whiteboards of active remote participants two projectors are necessary. They must be very bright so lights can switched on for writing and reading scripts etc. in the local theatre.

4.2.1.4. Control centre The central component of the teleteaching theatre

is the control centre. On the one hand it receives all

local audio/video signals and is connected to the computer inside the teaching terminal as well as to all applied media channels. On the other hand con- trol signals for the cameras and data signals for the projectors leave the control centre. To co-ordinate these signals and channels, the centre must fulfil the following tasks: * Remote control of the cameras. * Mixing the multiple video signals (cameras. video

recorder, etc.). * Mixing the audio signals (ceiling-mounted micro-

phones, microphone of the lecturer, etc.) * Preventing disturbing audio feedback. * Assigning media of the lecture theatre to media

channels of the teleteaching environment. * Selection of incoming media (speech, motion pic-

ture of remote participants, etc.) and assigning to an adequate presentation device. An important, still unanswered question is,

whether or not these tasks can be fully automated, if all requirements to a universal teleteaching environ- ment are sustained. If complete automation is not possible in this sense, the next question arises, which requirements can be fulfilled, when the control cen- tre is automated to the highest possible standard available today. Currently there is still one person needed to handle all devices in the control centre.

4.2.2. Teleteaching seminar room To provide the same functionality, the construc-

tion of seminar rooms has to be similar to that of teleteaching lecture theatres. As the number of pre- sent participants is limited to about 30 persons, instead of expensive projectors big monitors can be used to present teaching material and remote partici- pants. In addition the number of cameras and micro- phones decreases, which has also a beneficial effect

Fig. 5. Teleteaching workspace for a small group of participants.

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on the spent A/V mixing devices. The teleteaching terminal is here the central component as it is in the lecture theatre.

If only a small group of participants is to share on a single teleteaching terminal, slight changes must be made. The control monitor for the scan field and the monitor to display remote participants must be large displays, that all local participants can also see de- tails, and a second touch screen has to be installed so that all learners have comfortable access to it (see Fig. 5).

4.2.3. Teleteaching workplace A workplace for a single teacher without local

learners should be constructed as the teleteaching terminal. The only restriction at this constellation is, that the use of a black board is not supported. Within this teleteaching workspace the controlling tasks 1 to 3 described in Section 4.2.1.4 become obsolete and the teacher can in addition take on controlling task 4 to 6 by himself or herself.

4.4.3. Network

Teleteaching media channels can be realised by broadband networks, which connect the separate teleteaching workspaces. The demands to these net- works are providing synchronous media channels and fulfil real-time requirements. To transport all kinds of media four channel types are sufficient: audio, video, RGB and computer data channel. As teleteaching media channels usually transport data to all relevant workspaces, the need of multicast proto- cols appears, if network traffic is to be minimised.

One network technology, which performs all these demands, is ATM (Asynchronous Transfer Mode). It can provide teaching media channels that connect potentially as much workspaces as one likes by multicast protocol and guarantees bandwidth (for uninterrupted speech an video), maximal time data needs to travel as well as variation time.

A typical teleteaching environment contains four media channels to transport teaching media (Table 1).

With the use of all this teaching media channels a big network load (about 10 to 20 Mbps at a very good quality of audio and video) is been created. Especially because of the high network demands for the execution of a single teleteaching session, ATM

Table 1 Typical teaching media channels

Teaching media channel For

Full duplex, audio Lecturer, participants, audio teaching material

Half duplex, video Current speaker One-way, video Teaching media (black

table, overhead, etc.) One-way, RGB Computer applications Full duplex, data Whiteboard. shared

application, etc.

is a convenient alternative, as it provides already at this moment capacities of 622 Mbps, which allows about 30 parallel high quality teleteaching sessions.

Another advantage of ATM is that there are A/V codes (de- and encoder) that can be connected di- rectly to ATM networks and that solutions for RGB codes are tested in research laboratories at this mo- ment.

5. Use of teaching materials

To ensure that a maximum of information can be transferred to all teleteaching workspaces as well as other demands can be met (e.g. cost effectiveness and scalability), certain aspects in the application and use of instructional media need to be considered. Conventional media tend to pose more problems than electronic, since the latter are already present in digital form which can easily be transferred by third layer media. - Blackboard and transparencies: When distribut-

ing these two media using video channels it is important to consider the light conditions, the resolution and aspect ratio (4:3) of the cameras used and especially the size of the writing.

* The blackboard yields a good contrast in low and bright light, whereas transparencies, which are projected with the help of an overhead projector, produce results which need to be critically as- sessed. The only solution here lies in the use of a powerful camera, which can successfully capture the projected transparency.

* Handouts can be used in the same way as a transparency when used on the teleteaching termi- nal. The distribution of handouts, exercise sheets and lecture notes for use in lectures to remote

1796 R. Grehner/ Computer Networks and ISDN Systems 29 (19971 1787-l 797

students has proven very costly and time consum- ing. They must either be send out by mail to the according locations days in advance, or must be made available in electronic form, from which they can be printed.

. The electronic media of audio and video record- ings are exactly analogous to the audio and video conferencing systems and are hence not discussed in any detail at this point.

. Computer applications as electronic media or in- structional material cannot be substituted by third level media (except networked virtual reality), in contrast to the other items discussed above (cf. Fig. 1). They can be transferred, through shared application programs to remote locations in excel- lent quality. as long as they do not contain any audio or video material. To achieve this a sepa- rate audio channel (instructional media channel) or an additional RGB channel, which transfers the screen information, has to be used.

* Experimental setup and real models can be only partially captured by A/V conferencing systems. Small models and mini terminals are quite easily captured by the scan camera on the instructors computer. Apart from the utilisation and integration of con-

ventional and electronic instructional media the op- tion to completely substitute these through third level media which are already configured to make this information available to all tele-workplaces is often considered. Hence blackboard illustrations and trans- parencies can be substituted throughout the white- board tool, handouts through hypermedia document servers and audio as well as video recordings through A/V servers. The substitution of real life models and experimental set-ups could currently only be implemented through virtual worlds in cyberspace, although with this technique senses such as taste, smell and touch can only partially be stimulated at this moment.

6. Future developments

With the more widespread use of teleteaching technologies at universities and in private companies, a new and faster way of knowledge transfer between instructor and learner as well as within different training facilities will appear. Possible applications

of knowledge transfer between universities and com- panies using teleteaching environments are illus- trated in [5].

The development seems to be going into a direc- tion where more and more people consider the con- tact with third level teaching media as normal and pleasant and wish to make use of the advantages inherent in teleteaching to achieve the highest possi- ble degree of flexibility as far as their location is concerned. Currently limitations as far as the ‘mobile teleteaching’ are concerned persist. If mobile com- munication was able to handle network connections with a large bandwidth, then students in areas of low population density could benefit from a virtual edu- cation similar to one they would receive at a ‘real’ school.

The call for more flexibility in terms of location and lower costs for central training facilities could lead to a change in the composition of teleteaching environments. Whereas currently the main objective is to create environments which provide few teleteaching workspaces with a large audience capac- ity (e.g., teleteaching lecture theatres) and few in- structional media channels. the future structure may produce many tele-workspaces for small groups that are capable of processing many media channels.

This development may culminate in cyber-teach- ing and learning in a virtual world, where instructor and learner have access to all media channels that correspond to human perception. Through this method second level media are substituted, as they can be represented in cyberspace. The lecturer could in this environment simply use a virtual blackboard to illustrate the lecture content, which at the same time would be accessible by the learner to write down ideas or solutions to problems.

All visions of future teleteaching forms, see the instructor at the centre, who cannot be substituted. He or she will always continue to be in charge of didactic structure and selection of articles as well as the sensible use and application of teleteaching me- dia.

Acknowledgements

The project is sponsored by the Federal Ministry of Education, Science, Research and Technology and undertaken in co-operation with the RRZE (Regional

R. Crehner/ Computer Networks and ISDN Swtems 29 (1997) 1787- I797 I791

Computing Centre Erlangen) and IMMD IV (Chair of Computer Operating Systems).

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[5] C. Langenbach. R. Grebner, F. Bodendorf, Potentiale und Perspektiven multimedialer Kommunikations- und Koopera- tionssysteme in der wissenschaftlichen und betrieblichen Aus- und Weiterbildung, Berlin. 1997.

[6] M.G. Moore. Three types of interaction, in: K. Harry, M. John, D. Keegan (Eds.), Distance Education: New Perspec- tives, Routledge, London, 1993.

[7] 0. Peters, Understanding distance education, in: K. Harry, M. John, D. Keegan (Eds.), Distance Education: New Perspec- tives, Routledge, London, 1993.

[8] F. Vester, Denken, Lernen, Vergessen, Minchen, 1996.

Robert Grebner, born in 1966, studied

at the University of Erlangen-Nurem- berg where he received a first class hon- ours degree in computer science in 1993.

Between 1984 and 1988 he worked for Koch Datentechnik, a software com- pany where he was responsible for the development and maintenance of indi- vidual software for medium and small- scale enterprises. In 1989 he worked for the Institute of Computer Science at the University of Erlangen-Nuremberg,

where he added a rollback failure recovery to a distributed operat- ing system kernel. Between 1990 and 1991 he worked for the Department for Automation at the Research Center of Siemens AG in Erlangen. He developed a software system for monitoring communication between controlling systems and computer numer- ical control (CNC) machines. In 1989, together with a partner he founded a software company, which specialized on systems for parallel demands based on active software objects.

Since 1993 he has been a Ph.D. student at the Department of Information Systems at the University of Erlangen-Nuremberg. His main research fields are CSCW where he focuses at an integrated approach for collaborating and co-operating Workgroup and workflow systems based on distributed software agents. For three years now he has worked in two teleteaching and teleleam- ing projects sponsored by the Federal Ministry of Education, Science, Research and Technology under the auspices of the DFN-Verein (Association for Promoting a German Research Net- work).