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Stephen
Bostock Distance Learning Notes on Multimedia and Hypermedia
1 Introduction 4 Multimedia 5 Hypertext
Distance Learning Notes on Multimedia and Hypermedia 1 Introduction This section of the Unit illustrates and discusses two related ideas - multimedia (MM) and hypertext. Multimedia is much broader than its use in education and training - all sorts of computer applications are becoming multimedia. Important areas are personal productivity software, business presentations, public kiosks for information, education and training, marketing and selling, and home entertainment. Also, hypertext is commonly found in the user interfaces of many applications. So ideas in this topic are common to many types of applications outside education and training. Development and authoring of MM will be dealt with later in the Unit. 2 Learning Objectives After this topic you should be able to
3 Learning Resources The resources for this topic are:
4 Multimedia 4.1 Recall exercise Reflect on the difference it would make to your learning if you had only these printed notes or only an audiotape of them or only a lecture with the tutor speaking them. In the table below write down the differences, and why. _____________________________________________________________
Audio tape
Lecture
__________________________________________________________ 3.4.2 A framework of terminology The word 'media' is used in different ways. A medium is a transmission channel, as distinct from the messages being transmitted, the transmitter and the receiver. In learning interventions, a teacher is the dominant transmitter and a learner is the receiver but there are also messages moving from learner to teacher through the same or different media. Media have three aspects:
e.g. tape, paper,.. We will consider these in turn. We will also consider how human senses map onto these characteristics. Technological media types This is the most general, and traditional, classification of media. For example, television, print, a lecture and a microcomputer are media. The transmitter can be a teacher in a room, or the designer of a television programme, or of a computer program. The common media at this level are listed below (with an indication of symbolic modes and degree of user control, for later reference):
Many of these physical media are being computerized. Computers also can generate other media, or types of applications, all potentially with many symbolic modes:
Laurillard (1993) refers to these as educational media, even though they are based on a single hardware technology, but using different software technologies. They are examples of 'virtual media' (see later). The messages in all the media above are designed in advance. The following are passive communication media with no processing of their own but facilitating interaction between learners and tutors:
Laurillard (1993) discusses these types of media and their selection when designing instruction. In particular, she emphasizes four characteristics of them, which she calls discursive, adaptive, interactive and reflective. Now read Laurillard pp.97 - 105 and 176-178, in the appendix. 3.4.3 Symbolic Modes of media The most important effects of a medium's technology are the types of symbols and of interactions, which it permits. For example, audiotape has no pictures, a computer with a sound card is capable of outputting speech while one without is not. We can identify the symbolic modes, which any medium is capable of presenting, for example, written text, speech, still images, and moving images. If we consider computer-based media, as well as the outputs transmitted or presented, being interactive, we can also consider the modes of inputs. Computer outputs to users and inputs from user appeal to particular human senses: sight, hearing and touch. Any of the following symbolic modes of output can be used in any of the computer based media listed above.
(these all appear on a monitor)
As many traditional media are being replaced by digital equivalents, what is important is the symbolic modes of input and output (and the type of learner control, see later). These are all possible modes for transmission (output) by a multimedia computer with a modern display screen and loudspeaker. 'Desktop Multimedia' essentially means multi-mode transmission by computer-based media, in particular with sound or video. Some definitions of multimedia are given in the figure below. _________________________________________________________________ Some definitions of multimedia Multimedia educational software
is often a glitzy version of old
technology. We define multimedia as anything
that requires more than two trips to
the car. Multimedia lets you design a
continuous discovery What is multimedia? Computers,
isn't it? refers to combining different
electronic media , commonly computers
and videodiscs Sound and video add so much. If
a picture is worth a thousand words, a
movie clip or a sound clip is worth a
thousand pictures. "And what is the use of a book"
thought Alice, "without pictures or
conversations?" __________________________________________________________________ Output as movement (robots, Braille pads) requires specialist hardware. The number of output media possible with small computers has improved dramatically in the last 20 years, from monochrome fixed width text to multiple fonts in any size and colour, from low resolution monochrome graphics to high resolution colour graphics, from simple beeps to high-fidelity quality music and voice recordings. However, input is still limited to
3.4.4 Senses Following media and modes we can also distinguish different human senses: sensory modes are visual (eyes), auditory (ears) and touch (fingers...). But the symbolic meaning of information crosses the senses. Language (verbal) information can be auditory (speech) or visual (text). Non-verbal information can be auditory (noise, music) or visual (images, graphics, see table below). Sound is a relatively new sense for computer output and has been made available for MPCs by cheap sound cards. Before MPCs computer output was visual (with an occasional beep), input was touch and both were verbal, so the use of the auditory sense is mostly new. Whereas touch and visual information is fixed in space but not in time, audio is fixed and limited in time but not in space. It can be output simultaneously with visual information without taking screen space or distracting attention from the screen. As background music it can convey mood and signify ending or beginning of activity phases. Like video, the human voice can convey emotion and subtle information impossible in text. Noises can add richness to interfaces by emphasizing interface metaphors, e.g. button clicks or musical chords for confirmation or to gain the user's attention. ___________________________________________________________________ Symbolic modes classified by human sense and language Symbolic modes Sense modes visual
text
images, video, graphics, touch keyboard, Braille mouse _____________________________________________________________________ 3.4.5 Media Processing and Interactive multimedia Physical technology also determines the processing which can be performed by the medium. Information is not simply delivered to the senses and then represented in human memory; users can control media during learning, to different extents. For example, TV transmission has multiple symbolic modes but provides no processing or user control (except to switch off). Videotape can contain the same content and modes but offer some user control over pace and repetition through its sequential access. A videodisc can contain the same content and modes but offers complete control over presentation by random access to screen frames and by searching facilities. Computer-based media are distinguished by their processing capabilities. As well as offering random access they can embody the intelligence of the tutor (transmitter) to some degree, responding to the user's inputs by presenting different content and using different modes (they are adaptive). Interactive Multimedia (IMM) is software where the learner has significant control (for example, see hypermedia later). Multimedia is woven combinations of text, graphic art, sound, animation and video elements. When you allow an end user to control what and when the elements are delivered, it is called interactive multimedia. When you provide a structure of linked elements through which the user can navigate, interactive multimedia becomes hypermedia. Tay Vaughn, Multimedia, 2nd edition, 1994. The design of the interactivity (including instruction) allows the user to access or modify the content. TV gives the learner no control, it plays from beginning to end. The simplest type of control is sequential in a linear medium like tape - the learner can pause, rewind, restart and possibly play it backwards. Because MM computers store their content on random access devices (discs) they can offer full random access to all content, or any other type of access. Multimedia encyclopedias offer several types of access to their content based on searching, browsing, and hyperlinks (see later). Furthermore varying degrees of adaptation or intelligence can be built into the software. Software can easily give different responses to user actions (e.g. feedback to answers). It can monitor user performance and adapt its output to suit it. Intelligent Tutoring Systems can adapt both the content and their teaching style to individual performance. The balance of control between learner and software is an important feature of any software, and must be appropriate to its purpose. Too little control, and the learner is hampered and frustrated. Too much and they may get lost or achieve little. 3.4.6 Multimedia and mixed media It is interesting to note that the modes and processing capabilities of any particular physical medium need not be used fully in an application or by a user. In this case a virtual medium is created with lesser facilities than that which the physical medium is capable. For example, a videodisc could allow the user only to play straight through, and the Windows Sound Recorder application is a virtual tape recorder. Different types of educational software are different virtual media. An enthusiast’s view of a MM computer is that it is a 'supermedium', providing the advantages of all other media: capable of delivering content in all modes and with unrivalled processing abilities. In multimedia we have an astonishing new medium. It impact has been likened to the Gutenberg revolution, but this is a serious understatement of its power. (D.Laurillard, 'Teaching and Technology: Which leads?', Alt-N July 1994, p. 5-7) A skeptic’s view is that it emulates some other media - a video, a human lecturer - quite poorly and should not be used as a replacement. It is not being suggested that multimedia should be disregarded, or has no role to play. Rather the point is that there is no evidence that multimedia serves any purpose in training (M. Elsom-Cook, 'Multimedia: the emperor's new clothes?' DLT News, 6, p.1-2, 1991) What distinguishes a MM computer from other media is
We should distinguish multiple media from multimedia. At the level of a curriculum or course we should generally have a mix of media: personal contact with teachers, paper materials, videotape, computer programs. This is multiple media. At the level of a computer program, it can output a variety of modes, all from the same software. This is commonly referred to as multimedia or desktop multimedia (which should be 'multimode'). The term multimedia has for several decades been used to mean mixed media and it has recently been adopted by the computer industry to describe hardware and software capable of interactive, multimode applications (see MPC below).
3.4.7 Activity In the table below, tick the cells where each general medium is capable of the specific media/mode for output, control and input. Different types of computer-based applications are lumped under MPC2, without distinguishing the virtual media it can generate.
3.4.8 MPC2 The MPC standard defined the minimum functionality an IBM-PC compatible computer should have in order to be considered capable of delivering MM software. It is maintained by the Multimedia PC Marketing Council (1730 M Street NW, Suite 707, Washington DC 20036 USA). It was replaced in 1993 by the MPC2 standard which is more realistic for current software(see figure). In practice this means a 486 PC with double speed CD-ROM and 16 bit sound card. The CD will read CD-audio, digital WAV and MIDI files, and Kodak Photo-CD files. Super-VGA graphics should have at least 256 colours and preferably 64K colours. This hardware will provide hi-fi quality sound, good quality still images and acceptable quality moving video in a window. Note that the identification of multimedia with CD-ROM is erroneous. CD-ROM is just a very large, very slow type of read-only disk. It is useful for publishing large volumes of text, data or software, which may have nothing to do with MM. However, because MM data is voluminous (photo-realistic images, sound and especially video), a CD-ROM (at over 600Mbytes) is the cheapest, easiest way to publish it. However, the basic CD format was designed for hi-fi audio (in particular to allow Beethoven's 9th Symphony at 16 bit, 44 MHz quality on one disc). While later CD standards dealt with other forms of data, current CD drive speeds are slow especially for delivering video in real time.
The MPC2 specification (summary)
25 MHz 486SX minimum 4MB minimum, 8 recommended a 3.5 in. 1.44MB floppy drive and a 160MB fixed drive minimum. CD-ROM drive capable of reading 300K/sec sustained transfer. (i.e. 'double speed'). CD-ROM XA ready . Capable of reading multisession written CDs. CD-ROM with CD-DA (Red Book) outputs and volume control. 16 bit digital-to-analog and analog-to-digital converters. Microphone input. Music synthesizer capable of multi-voice, multi-timbre, six melody voices and 2 percussion. Analog audio mixing. Display of 64K colours at 640 x 480 and blit bitmaps fast enough for video at 15 frames/sec in 256 colours for a 320x240 pixel video window. 101-key keyboard, two-button mouse. Serial port, parallel port, MIDI I/O, joystick port. Binary compatibility with Windows 3.1. Note on MPC3: 3.4.9 Designing with media How should various modes be used in designing software? There are two aspects: media as content and as interface. The discussion below concentrates on sound, but similar points could be made about video. As content, a choice of an appropriate mode is often clear. For example, sound is appropriate for conveying information about music and birdsong. Text would convey less information and keep the user further removed from the external reality being represented. Similarly, video can show clips of historical documentaries and animal behaviours better than still images or text. On the other hand, analysis of either of these would need text. So the answer to the question 'What is the best single mode for output?' is often clear. Should we use more than one mode for the same content? One answer to this is that we should provide alternative outputs for different users, to allow for individual differences in users. However, there remains the issue of multiple simultaneous modes delivering the same content: will the user learn more if the content is delivered in two ways at once, for example, as text and voice? The first point here is that for non-verbal modes, no two modes can deliver the same content, but only related information. For example, a picture of a cat and the sound of a meow are different content. But the spoken word 'cat' and the text 'cat' are very similar in content. It has been argued that users learn better with two modes, but there are potential problems if the speed of presentation of the two modes is not synchronized. Readers read at their own rate, but they cannot easily control the speed of speech. The user's control over text (e.g. scroll bar) and voice (e.g. Recorder controls) are different so it would not be possible to control both simultaneously. Actions during learning from the two modes is also intrinsically different; text is scanned visually in quite complex ways while scanning or re-listening to a speech recording is limited and awkward. All this leads to a conclusion that simultaneous use of two verbal modes is fraught with problems. Turning now to modes as part of interfaces, just as GUIs have improved on text command line interfaces, the addition of sound and video seems to have great potential. 'Auditory icons' use everyday noises to enhance interface metaphors to give the user confirmation of actions or warnings, for example when selecting an icon. 'Earcons' are musical notes connected to actions. Speech (or video) can be used to deliver verbal information such as introductions or praise or advice. The pitfalls of audio in interfaces include annoyance by the repetition or delay of longer sound sequences. Noise can distract the user's concentration. Cultural differences may make some voices or music irritating or lacking in significance. Sound should be presented in small sections so that the user can control its use, and users should be able to turn sound off if an alternative mode is available. Of course, there are many cases where the user's can make much better use of sound than other interfaces: the blind, the illiterate, the very young, and anyone using an application in situations where reading is difficult but listening is not. 3.4.10 Virtual reality Virtual reality is a mix of multimedia and simulation. Simulators based on physical models are well known (e.g. wind tunnels). Interactive computer simulations are common as games (e.g. Flight Simulator). Interactive virtual reality (VR) is an extension of interactive simulation and may be multimedia. By adding three dimensional images and various special input and output devices such as goggles, helmets, gloves and walkways, the user is taken 'inside' the interface by excluding the real world. Realism requires high-resolution graphics and rapid responses, and therefore terrific processing power. All graphical objects within view must be redrawn 30 times per second for realistic smooth movement. Directional sound can be used, and in future possibly smell. Commercial applications are flight simulators for training pilots, architectural simulations of buildings for visualizing designs, molecular structure simulations for biochemists, and simulations of oil tanker loading and unloading for merchant marine officer training. 3.4.11 Further reading A good general book on Multimedia
standards, design and authoring is: Does the choice of media affect learning? There is no simple answer, and there are differing views on the importance of media per se in learning.
The nature of interactivity is complex and raises important questions for instructional design. Alexander Romiszowski discusses these in 'Developing interactive multimedia courseware and networks: some current issues.' (pp. 57-78 in C. Latchem, J. Williamson & L. Henderson-Lancett (Eds) Interactive Multimedia: practice and promise. Kogan Page, London. 1993. For more on the uses of physical media read Part II 97-180 of Diana Laurillard (1993) Rethinking University Education, Routledge. (not provided). For a critique of the classification of media as adaptive, interactive, reflective and discursive, see S.J.Bostock 1995 (Tech Report or J. Instr. Science). (Appendix) For discussion of the effective uses of multimedia in education , see Betty Collis 'Anticipating the impact of multimedia in education: lessons from the literature', Computers in Adult Ed. and Training, 1991, 2 (2) 136-149. (Appendix) For a discussion of some uses of
sound: 3.5 Hypertext 3.5.1 Recall Exercise Describe the differences between your use of Unix 'man' (manual) pages through a terminal emulator (linear text) and a Windows Help file (hypertext, possibly with graphics). In the box below list the output media (text, graphics), the input media (e.g. mouse, keyboard) and type of user control (sequential, random access). (If you have not used them, do so now: when logged on to a Unix machine type 'man fgrep' for example. When running Windows from the program manager or any application, press the F1 key.)
______________________________________________________________________ Unix man Windows Help Output
Input
Control _______________________________________________________________
3.5.2 Introduction Hypertext is usually defined as non-linear text, in which the content is organized as units called nodes. The relationships between the nodes are defined by links, rather like a cross-reference in a book. Links can define an associative relationship between two nodes (based on text content) or can provide access to organizational information (like a Contents). Links are activated by moving a cursor onto a hotword in the text, a screen button, or hotspot on a graphic, and selecting it. Hotwords are traditionally underlined. The node with the hotspot is the link-anchor and the destination is the link-end. Links can be one-directional or bi-directional. In a GUI the mouse cursor is moved and clicked. Typically, in a text interface the cursor keys move a highlight bar over hotwords and the Enter key selects. On selecting a link, one of two things happens. Most simply, the original text node is replaced by the new node, with its own hot-objects. Alternatively, a smaller pop-up window of text appears over the original node. When this is dismissed the original node remains. Additional elements in many hypertext interfaces are
Hypertext is not new - Ted Nelson first used the term in the 1960's. More recently it has been referred to a virtual text because the user decides what parts of the hypertext body he/she sees. This will be different each session and for each learner as they pursue their own goals or curiosity through the associative links. It has been argued that hypertext is the natural form of information for display on a computer. The size of the screen is a convenient node, whereas it is not convenient for displaying longer sequences of text. Scrolling the text through a window gives a poorer ability to relate sections of text than in a book, where it is easy to visually scan and refer to other parts of a page or other pages. A cynical view of hypertext is that it is only necessary because of the limited size of computer screens. 3.5.3 Advantages and disadvantages Advantages of hypertext:
The use of hypertext for learning has some potential disadvantages.
On balance, then, hypertext needs augmenting.
The hype of hypertext may be justified. It can provide a computer- supported information environment which can add to our appreciation of the text, can go some way towards aping the mental agility of the human mind, can allow navigation along patterns of association, can provide a non-linear information environment. But the problems of constructing non-linear documents are not few and can prove to be very complex. (Patricia Baird, editor of the journal Hypermedia) 3.5.4 Activity Exercise on Hypertext: Take the section of text above. Identify the nodes in it and number them. Write down the links you would put between them. You could do this by photocopying the paper and cutting it up, then pinning or pasting it on a board, and drawing the links. Alternatively, take the electronic copy of these notes and paste sections onto pages of a simple Toolbook hypertext application. Where would the user start? What goals should he/she have? What additional links could be added? 3.5.5 Hypermedia Hypermedia is simply the convergence or overlap of hypertext and interactive multimedia. Instead of being only text, the nodes can now be any medium or mode of output, for example, images, animations, sounds, video sequences, and other interactive programs such as simulations (so hypermedia can be both multi-mode and multi-media). This is technically possible on modest computer hardware. Some people use 'hypertext' and 'hypermedia' synonymously. The are additional advantages when adding non-text modes to hypertext. Many subjects can benefit from non-text modes of content and interface. For example, photographs, music and video sequences convey more than text descriptions of them. There may be additional problems for the user also. It may be easier to be confused or lost, and certainly it is easier to be distracted from serious learning goals by attractive media regardless of the relevance of their content. If multimedia is the 'supermedium' then hypermedia can be seen as 'super-interactive multimedia' because it gives the user full control. It can output any symbolic modes or virtual media, in any order and under user control. An application providing a subset of possible modes and links can therefore provide any required modes or type of user control. The problem is - which? If specific learning goals are to be achieved, what particular combination of possibilities is to be used? The general answer to this is the use of instructional design. Hypermedia represents all the possibilities, but the designer must select which of these multimedia should be used and how, if a learning objective is to be achieved. The design issues for hypermedia are therefore those of hypertext and those of multimedia! Hypermedia is likely to be useful in Resource Based Learning. A good example of this is any of the several multimedia encyclopedias now available. A resource, however, is just a resource. On its own it achieves little although browsing can be enjoyable. If learning goals are to be achieved then the resource must be used within a context of structure learning activities. In particular, is hypermedia any use in training? On the face of it there is a conflict: specific skills must be learnt but hypermedia gives the user freedom to learn anything. Clearly the used must have an external goal to focus his/her use of hypermedia, but this may not be adequate to achieve performance goals in limited time if the user does not sufficient skills in learning and in controlling the software. On the other hand, in the long run we may be seeing a shift from instructional technology to performance technology, from training in advance to just-in-time learning where the user learns what is needed as he/she needs it. In this case the learning goal is specific and immediate, and augmented hypermedia may be the best technology. 3.5.7 World Wide Web The Internet is the global network of networks. Many computers on it offer free (though limited) access for remote login using programs like telnet. They also maintain archives of files of documents and software for free copying, using file transfer protocol (ftp). Retrieval of files was made easier firstly by software called gopher, which presented the user with a hierarchy of menus of items from which to select local files, other gopher sites or remote login sessions. In the early 1990s a new method of using remote archives was created at the CERN European Laboratory for Particle Physics, in Switzerland. Instead of a menu, the World Wide Web presents the user with hypertext pages. The links are to other pages at the same or any other site worldwide. Software called Web browsers collects a copy of a web page along with its link addresses, so that when a hotword is used locally, the link end web page is retrieved from wherever. Furthermore, Web readers (such as Netscape and lynx) can read gopher pages, so the WWW includes all the types of Internet searching and retrieval facilities. WWW pages are basically text pages in which are embedded codes (tags) in the hypertext mark-up language (html). Web pages can thus be created either with a text editor or with special software which allows interactive editing of pages as they will appear to a browser (WYSIWYG). By using additional software on the host computer at the request of html tags, additional interactivity can be built into pages, so that the user can fill in forms and have the answers analyzed, or click on different hotspots in graphics. Because the tags can 'pull in' free-standing graphics files for copying along with the Web pages, a user with a suitable browser can see images and sounds. (The browser has 'readers' for different types of accompanying files) The WWW is therefore effectively a global hypermedium. Ironically, the earliest suggestions of hypertext by Vannebar Bush in 1945 envisaged a geographically dispersed hypertext, but this idea has only recently come to fruition. There are instructional materials being 'published' on the WWW. The advantages include having only a single copy of software to update and yet having it available to the whole world on any platform. There is also doubt about the wisdom of this publication medium, at least with current web authoring tools and bandwidths. 3.5.8 Activities 1. Use the Hypermedia Toolbook application. Write down your learning goals as questions in advance. Write down the headings of the answers you find. Also write down what you think is important which you were not looking for. 2. Use interactive pages on the WWW. The addresses (Universal Resource Locators, URLs) will be posted by email or in the course conference. You will need a Windows graphical browser like Netscape to use them. 3.5.9 Further reading For an account of hypermedia and some
design issues: A systematic account of hypertext
ideas is given in An introduction and history is
provided in On the issue of using hypermedia with training objectives, the following take different views. Depover and Quintin see a problem remaining while Cortinovis tries to resolve this within a hypertext structure.
One initial attraction of hypertext is its similarity with models of long term human memory. The two papers below first propose making use of this, and then report that in practice it did not work.
Volume 21 (1992) of Instructional Science is a special issue on Computers and Writing: issues and implementations. Amongst the papers are two examples of hypertext in use:
The most famous example of
collaborative use of hypertext (the
Intermedia project) was at Brown
University. It is described in the
following, and elsewhere. |
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