Course Notes on HT Unit --- Hypertext and Hypermedia
SEE KMS SYSTEM FOR MOST OF NOTES FOR THIS UNIT!!!
What is Hypertext?
- Definitions
- Bush (Atlantic Monthly, July 1945, As We May Think on memex: "The owner of the memex, let us say, is interested in the origin of the bow and arrow .... He has dozens of possibly pertinent books and articles in his memex .... First, he runs through an encyclopedia, finds an interesting but sketchy article .... Next, in a history, he finds another pertinent item, and ties the two together. Thus he goes, building a trail of many items. Occasionally he inserts a comment of his own, either linking it into the main trail or joining it by a side trail to a particular item."
- Bush on association: "... The human mind ... operates by association. With one item in its grasp, it snaps instantly to the next that is suggested by the association of thoughts, in accordance with some intricate web of trails carried by the cells of the brain .... Man cannot hope fully to duplicate this mental process artificially, but he certainly ought to be able to learn from it ... Selection by association, rather than by indexing, may yet be mechanized."
- Hypertext (and Hypermedia) coined by Ted Nelson --- Meaning: Non-linear text (multimedia)
- Node: fundamental unit of information in a hypertext document, like one of Bush's items, ideally a small portion of the document that covers one concept, sometimes fitting on a single screen (though it can be as small as a single word or as large as a full document, e.g., a book). In hypermedia it may contain a combination of text, graphics, and other media.
- Link: an electronic cross reference that connects nodes. When a reader selects a link, the hypertext system changes to reveal the contents of the node to which the link refers. Links may have types, such as definition to designate the type of connection that the target represents.
- Anchor: or link anchor, is a part of a node, that is represented with an on-screen indicator of the presence of a link, that can be selected to activate the link.
- Hyperdocument: a hypertext document.
- Hyperbase: a collection of hypertext documents that are linked together.
- HyTime: ISO standard 10744, for hypertext, hypermedia, and time-based documents (performances) --- see S.J. DeRose and D.G. Durand, Making Hypermedia Work: A User's Guide to HyTime, published by Kluwer, 1994.
- Fundamental Concepts
- Associative search using links and windows
- Browsing, serendipity
- Computer Supported Cooperative Work (CSCW)
- Hypermedia extends to audio, video and more complex rendering than windowing
- Systems
- NoteCards to HyperCard to SuperCard to ToolBook
- OWL's Guide (scrolling, outlining, pop-ups, xrefs)
- KMS on Sun and Apollo (and DECstation)
- World-Wide Web with Mosaic, Netscape, cello, ...
- Popularity
- HyperCard bundled with Mac systems
- Hypertext 87, 89, ...
- Other conferences, workshops, books, electronic products
- Problems
- How to build links
- Learning anew how to organize and write
- Navigating, not getting lost or unduly distracted
- Lack of standards --- will Xanadu succeed, or emerge from WWW
Hypertext and Information Retrieval
- Commonalities
- Both were proposed by Vannevar Bush in 1945
- Help people explore in a large collection
- Common Techniques
- Secondary storage
- Shared access to database
- Mixture of pre-analysis and post-searching
- Use: associations, xrefs and citations, display technology
- Need for automatic: indexing, link building
- Keyword searching needed in hypertext systems
- Browsing, following references needed in IR systems
- Different Emphasis, Culture
- Search vs. Browsing
- Word or query matching vs. Link following
- Static vs. User changeable collection
- Limited vs. Advanced use of Displau Technology
- Text vs. Multimedia
- Indexing vs. Link building
- Huge vs. Medium sized collection
- Tagged vs. WYSIWYG editing and access