Discussion Question
1. Discuss the differences among multimedia, interactive multimedia, hypertext, and hypermedia.
Multimedia—the combination of text, graphic, and audio elements into a single collection or presentation—becomes interactive multimedia when you give the user some control over what information is viewed and when it is viewed. Interactive multimedia becomes hypermedia when its designer provides a structure of linked elements through which a user can navigate and interact.
When a hypermedia project includes large amounts of text or symbolic content, this content can be indexed and its elements then linked together to afford rapid electronic retrieval of the associated information. When words are keyed or indexed to other words, you have a hypertext system; the “text” part of this term represents the project’s content and meaning, rather than the graphical presentation of the text. Hypertext is what the World Wide Web is all about.
When text is stored in a computer instead of on printed pages, the
Computer’s powerful processing capabilities can be applied to make the text more accessible and meaningful. The text can then be called hypertext; because the words, sections, and thoughts are linked, the user can navigate through text in a nonlinear way, quickly and intuitively. Using hypertext systems, you can electronically search through all the text of a computer-resident book, locate references to a certain word, and then immediately view the page where the word was found. A word can be made hot, as can a button, thus leading the user from one reference to another. Click on the word “Elwood,” and you may find yourself reading a biography or resume; click on “mortgage” and a calculator pops up. Some authoring systems incorporate a hypertext facility that allows you to identify words in a text field using a bold or cooled style, then link them to other words, pages, or activities, such as playing a sound or video clip related to that hot word.
2. Your boss wants you to create a hypermedia system for Web visitors to find technical support information about your company. What are some of the implications in creating this system? Should you hand-build the links or use an automatic indexing system? Why?
Hypermedia: The art of hypermedia design lies in the visualization of these nodes and their links so that they make sense, not nonsense, and can form the backbone of a knowledge access system.
The simplest way to navigate hypermedia structures are via buttons that let visitors access linked information (text, graphics, and sounds) that is contained at the nodes. When you’ve finished examining the information, you return to your starting location.
Hypermedia can take advantage of powerful capabilities that are becoming clearer as the new multimedia medium matures, giving us a greater choice in exploration, if not in outright plot definition, for example. However hypermedia restricts the speed of website so it takes more time to open the web site.
Lessons Learned from Open Hypermedia Systems Research:
Almost every single OHS (Open Hypermedia System) project has reported on experiences, results and services that they find useful and important enough that they should be part of the WWW for everyone to use (e.g., [9,10,24,25,26]). This section accumulates these community experiences and groups them into five general OHS lessons learned: open set of integrated applications; flexible data model and user interface; multiple document views; advanced authoring support; and, document and structure access control.
Implications of hypermedia application design:
The first attempts at applying a new technology are often modeled on the strategies used in the one that is being replaced. Indeed many hypermedia applications use the computer as an emulation of a piece of paper. It is wrong to begin design of hypermedia applications with the focus on the traditional book, with extras added on. It is worth being open minded and considering using graphics as the base medium and linking in the various other media to provide background information where required. Before the base media is selected there should be analysis of the target audience and the material that has to be presented. Next comes the creation of a storyboard, which is essentially a general outline of the production. Details of linking should be added to see how each step is interrelated On the face of it, it sounds easy except that there are a unique set of authoring problems associated with linking media such as video and sound. These problems include navigation in hypermedia, pacing of the application, linking to and from a moving image or sound, empowering the user and production quality.
Navigation in Hypermedia: Users can get lost in hypermedia applications very easily. Links can lead off at a tangent to other aspects of the application and these to others until the way back is lost or no longer available. It is one of the largest problems to provide users with suitable maps depicting the various ways through the combinations of sound, video and text.
Pacing the application: A movie director controls the pacing of a film by determining the length of each sequence within it and by using transitional effects to join each one together. Transitions can be used to great effect in providing suspense, thoughtful passages and shock horror. In hypermedia the author cannot control the user without loss of interactivity. So if a user is allowed to control his own pacing then the author must decide in advance how long each sequence will be, whether the information can be conveyed in a few seconds or whether several minutes are required. The author must then provide the links to allow the user to branch to another aspect when the author feels it is acceptable. It is not suitable to force a user to watch the entire video from start to finish particularly if it will last for several minutes.
However, where control is granted then care must be taken over the flow of the application. If one branch from a video leads directly to another then some kind of transition effect is going to be needed in order to maintain continuity. A user can (and probably will) branch between scenes in a totally unpredictable order making suitable transitions very difficult to implement.
The element of time is possibly the biggest problem in linking into moving streams of sound or video. In most cases it will be straight forward enough to start at the beginning and proceed in a linear fashion to the end. This is acceptable when the sequences are short or the author intends for the entire sequence to be uninterrupted. But at other times it may be necessary to allow entry or exit at any time. For example a famous speech would be expected to start at the beginning but may need to be skipped through to find a particular passage. If a user is allowed to jump into a video sequence at any point then difficulties occur due to the compression of the data. For example, the 2000th frame on disk may not contain the whole picture merely a reduced version that is meaningless on its own. To enable video entry at any point then absolute (anchor) frames must be placed in the compressed sequence at the appropriate position. The entry point intervals are at the author's discretion and of course incur costs regarding storage media and accessing time. It is recommended that discrete calls to video are kept to a minimum.
Another problem of linking to moving sequence is how to inform the user that a link is available. Overlaying text on the video screen to provide a 'button' can be one effective way and others include using moving icons that can be selected as the sequence is playing. Moving icons must not move too rapidly or they become difficult to select. Icons can be made active at different times during the sequence and provide links to different areas. As a sequence progresses a previous branch may become irrelevant to the current topic and be replaced by one more appropriate. Audio sequences present a different problem since sound is not visual unless it is represented in some manner on screen while it is playing.
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Indexing system :In many hypermedia applications (particularly those involving spatial or time structures) we need to provide the reader with a way to understand where he is and help him decide where to go next. The usual solution would include an index (or other access structure) to the elements we intend the user to navigate. However, this solution will require the user to backtrack from the current node to the index to see where he is or to move to another node, while ensuring that its current position is highlighted in the index. These navigational operations: moving backward to the index and forward to the target may disorient the user.
A good solution is to maintain an active and perceivable navigational object acting as an index for other navigational objects (either nodes or sub-indexes). This object remains perceivable together with target objects, letting the user either explore those objects or select another related target. In this way we will be able to interact with both the index and the target nodes.
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