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Moving images in multimedia computer aided learning packages

Howard R. Loxton and Keith A. Oldfield
Hong Kong Polytechnic, Hong Kong


Study in the age of IT and CAI will inevitably involve interaction with computer programs. Combinations of graphics and text, coupled with conditional branching program techniques, such that the learner is guided or steers a path through the material available, can be used for a wide variety of learning activities. Use of these techniques in some topics however, cannot be effective without the use of moving images on the monitor screen.

One method to introduce moving images onto the screen is to use interactive video techniques, with the moving images stored in CD-ROM or LaserDisk format. This type of image source enables specific sequences to be accurately located and accessed, although the speed of delivery to the screen depends largely on the data transfer rate from the source, which can extend for several seconds. Nevertheless, to be able to accurately access specific sequences within this time scale for presentation, in conditional branching learning programs which branch according to the learner response or choice, has clear advantages over the more common video tape sources, where access times can be in the one minute plus range.


A need has been identified in the Electrical Engineering Department of the Hong Kong Polytechnic, for students to become proficient in the operation of the oscilloscope before using the instrument in laboratory experiments. With class sizes of 50 or more, resources preclude the provision of sufficient oscilloscopes for prolonged and individually supervised use in both laboratory experiments and for extended experience acquisition.

The use of multimedia learning packages to assist in the learning of oscilloscope operation and the gaining of experience in display stabilisation was considered to be a possible solution to the problem, allowing learning and experience acquisition in a non-destructive environment. However this requires the use of moving images.

The Education Technology Unit of the Hong Kong Polytechnic was concurrently developing the use of interactive video for student learning applications, and this technique (which has already been shown to be a very effective teaching/learning medium) was seen to be a possible solution to the problem.

The technology has already been found to be particularly useful in other laboratory situations (Jones and Smith, 1990) and there are many advantages to be gained through this approach. It is possible for students to see certain experiments carried out that they could not otherwise perform themselves (Kahn 1986). Where there is danger of explosions, or exposure to toxic chemicals or electrical hazards for example. At times when departmental funds are being cut and lecturer, tutor, or demonstrator time is being reduced, interactive multimedia technology is a particularly appropriate way of making some practical situations more efficient and effective. It can lead to savings in laboratory times where the equipment/apparatus requires lengthy set up and cleaning operations. Computer simulations can save student laboratory time for large groups on the occasions when it is essential for tutors to check that equipment is set up properly before any measurements etc. can be made. Fully interactive multimedia packages provide self paced laboratory study and experiments can be repeated as many times as the student likes. Interactive presentations lead to less wear and tear on expensive equipment during the initial phases of instruction since students complete the program before actually using the real thing. Finally, programs can show actual equipment in use and through screen simulations students can practise and accomplish certain procedures before they try them out in laboratory/workshop situation.

Why moving images?

In using an oscilloscope to investigate time varying signals in engineering systems, the most difficult technique to master is to obtain a stationary and stable display of the signal waveform on the oscilloscope screen. A stationary and stable display is essential if measurements are to be taken, or if the effects of system parameter adjustments on the waveform are to be observed.

When a user knows what type of signal to expect to be displayed, the oscilloscope controls can be pre-set to enable the signal, when applied, to be immediately visible - only minor adjustments being required to produce a stable display. To be able to do this, the user needs experience, and this is what students lack when using an oscilloscope initially.

Typically they do not know what type of signal waveform to expect, neither do they know which controls to set in practice to display a given waveform. Since there are several controls on the oscilloscope, each of which can be used to change the display, it is unlikely that a 'trial and error' approach will be successful in stabilising the display. The key to successful oscilloscope operation is therefore to know which control to adjust, and how the adjustment will change the display, such that successive adjustments to each of several controls will cause convergence to a stable waveform display.

From the students' point of view, the access to oscilloscopes in laboratories cannot usually be at times which they consider to be convenient, nor for periods long enough for them to acquire sufficient expertise, because of operational requirements. Typically, students acquire this expertise over a long period of time (1 to 2 years) in the course of conducting laboratory experiments which require the use of oscilloscopes as tools. Often acquisition of these skills obscures the required concentration on reaching the actual objective of the experiments being conducted.

The requirement of the interactive package is for the student to successively adjust controls, observe the changes in the moving waveform, and achieve convergence to a stable image. Such a package therefore needs moving images on the computer screen of the results of control manipulation on the simulation.

The structure and content of the complete interactive video presentation is shown in figure 1. All the boxes labelled "Demonstration" are presented from the LaserDisk while those labelled as either "Test Yourself' or "Activity/Problem" are computer generated presentations.

Figure 1

Figure 1: Content and structure of interactive package "The Oscilloscope"

The package production

A team of 4 Polytechnic staff was identified for the production of the package. A Project Manager, A Subject Matter Expert, A Video Specialist and An Instructional Designer. The individual responsibilities were determined, each member of the team having to play more than one role. The project manager, for example, not only took responsibility for the overall running of the project (ie. ensuring that time schedules were adhered to etc.) but was also responsible for the integration of the laser disk video clips with the computer simulations and interactive exercises. 'Me subject matter expert was responsible for identifying the goals and objectives for the package as well as developing the content and associated video scripts. The instructional designer took responsibility for building in the interaction, development of testing strategies and formative evaluation. The video specialist was responsible for the writing of storyboards and production of any artwork as well as the production of the video tape and its editing into the right format for conversion to laser disk. Every member of the team were involved in the determination of a suitable hardware/software configuration for the presentation of the finished package. They all also played an active part in the review of all screen formats of the entire package.

The video taping was done partly in the Education Technology Unit's studio and partly on location in the Electrical Engineering Department's laboratory. The conversion of the tape to laser disk was done by an outside company in the UK.

The preparation, production and presentation hardware/software configuration

One of the major problems faced by the development team was the determination of a suitable hardware/software configuration for the delivery of the package. This arose out of the fact that many of the Polytechnic's academic departments (including Electrical Engineering) use IBM or IBM compatible machines. Some departments (including the Education Technology Unit) are working with the Macintosh. Any interactive video learning packages produced should therefore be required to run on any of the Polytechnic's systems thereby meeting the needs of all departments. All the development work was carried out using the system described below.

A Macintosh IIx with VideoLogic's DVAI Macintosh and 8-bit Graphics cards installed along with Apple's standard 13 inch colour monitor met the basic hardware requirements. VideoLogic also provides similar cards for the IBM and its compatibles. These cards along with their exclusive MIC (Multimedia Interactive Control) System H software puts a complete multimedia production studio into any Macintosh H or IBM computer. The DVA-4000 card allows live video to be played on any standard RGB colour monitor (in either PAL or NTSC) with ability to combine the live video pictures with computer generated text and graphics. The DVA card also allows pictures to be captured via a video camera.

The laser disc video pictures were captured via a Sony LDP 3600 Dual System Laservision Disc Player. The addition of an appropriate colour scanner, though not essential, proved useful in that some computer graphics were generated from colour photographs of oscilloscope screens using the scanner. This tended to speed up the process.

MacroMind Director, Authorware Professional and Studio 8 made up the major items of software used to create the computer simulations and other graphics screens. The MIC System II software already mentioned enables the creation and running of multimedia applications developed in MacroMind Director, MacroMind Media Maker, HyperCard and Authorware Professional. Authorware Professional is available for both the Macintosh and MS-DOS presentations while IBM Linkway is similar to HyperCard and it is possible to convert any HyperCard stack to IBM Linkway. Spinnaker PLUS, which is very similar to HyperCard, gives full colour presentations and will run on the IBM under Microsoft Windows.

The only other system requirement was for the Macintosh System Software to be version 6.0.3 or above and 32-bit Quickdraw must be installed in the Macintosh System Folder.


It is not possible to give a complete evaluation of the package at this point in time but it is undergoing extensive student testing. One thing we can say and that is the students who have already used the package report that they did enjoy the lesson and are finding it a valuable tool in learning about the operation of the oscilloscope. .

Video tape and laser disc production along with the technology required to deliver interactive video packages is not cheap and it is essential to be selective about the topics covered by multimedia interactive video presentations. Interactive videodisc technology in those areas of laboratory work mentioned at the beginning of this paper will more than likely continue to grow not only because of the advantages already identified. There are other benefits. Interactive video programs do allow students to easily review materials at a later date, they can relieve potential overcrowding of laboratories and workshops, they provide opportunities for students and teachers to better utilise their time (Jones & Smith 1990). Interactive video presentations can also be used in large group studies as well as by individual students. Many generic video discs are now available and with authoring systems such as HyperCard, Authorware Professional, Linkway and PLUS it is possible for lessons to be tailor made using these discs.


Loretta L. Jones and Stanley G. Smith (1990). Using interactive video courseware to teach laboratory science. Tech Trends, 35(6), 22-24

Kahn, B. (1986). Computers in science: Using computers for learning and teaching, Cambridge: Cambridge University Press.

Authors: Howard Loxton is currently the leader of the Curriculum & Instructional Services Section of the Education Technology Unit of the Hong Kong Polytechnic. Keith A. Oldfield is currently a Principal Lecturer in the Department of Electrical Engineering at the Hong Kong Polytechnic.

Please cite as: Loxton, H. R. and Oldfield, K. A. (1992). Moving images in multimedia computer aided learning packages. In Promaco Conventions (Ed.), Proceedings of the International Interactive Multimedia Symposium, 105-109. Perth, Western Australia, 27-31 January. Promaco Conventions. http://www.aset.org.au/confs/iims/1992/loxton.html

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