Hypertext Homework

Due by July 1

Some general comments: Many of you think hypertext = WWW. This is not true. There have been, are, and will be, LOTS of other hypertext systems with varying features. I think many of you need to go through the history of hypertext again, following links.

  1. Does the World Wide Web have anchors? Explain your answer.

    An anchor is the section of a node referenced in a link.

    It is quite difficult to use anchors in HTML and with most browsers. Following a page reference with #xxx and putting a link called xxx is the best we can do. Also since WWW only allows forward links it is not possible to go from a destination to an anchor in the source (directly)

  2. Why did Bush propose such a radical system as Memex?

    Because of the explosion in the quantity of scientific literature. Can you imagine if he were alive today!

  3. What are the two major link mechanisms used in hypertext systems?

    They either (1) replace the anchor with the destination node or (2) replace the entire source node with the destination node. The Web does the latter.

  4. Consider the following graph: and compute the Converted Distance Matrix on the nodes. 

        A  	  B     C     D     E     F     G     COD     ROC
------------------------------------------    ---     ---
A|  0     4     3     1     2     5     6     21      6.4
B|  3     0     6     4     5     1     2     21      6.4
C|  4     1     0     5     6     2     3     21      6.4
D|  2     3     2     0     1     4     5     17      7.9
E|  1     2     1     2     0     3     4     13      10.4
F|  2     6     5     3     4     0     1     21      6.4
G|  1     5     4     2     3     6     0     21      6.4
    -     -     -     -     -     -     -     --      ----
CID 13    21    21    17    21    21    21  CD = 135
RIC 10.4  6.4   6.4   7.9   6.4   6.4   6.4

  5. Compute COD, CID, ROC, RIC for the same graph, using the Matrix in #4.

    See above

  6. From the values computed in #4, identify index nodes, reference nodes, and candidates for the root.

    Index nodes: None of the nodes have a large number of outgoing links, so I would say none.

    Ref nodes: A has the largest RIC and the 2 ingoing links as opposed to 1 for the others. This may not be sufficient to make it a reference node (like the bibliography of a book)

    Root: E is a good choice

  7. What are two problems that may occur during navigation of a hyperdocument?

    1. Lost in hyperspace, i.e., not knowing where you are

    2. Inability to know where you are.

  8. What features of hypertext are not included in the World Wide Web?

      no graphical view - either static or dynamic

      no bidirectional links

      no filtered hypertext

      no context-sensitive links

      minimal sneak preview (just the URL)

      no unique anchors

      no complete history list (just nodes "backed out of") few information retrieval mechanisms

  9. What is a metaphor?

    A metaphor is a way to understand a new object by relating it to a known object. The Web uses a "page" metaphor. We understand what a Web page is partly because of our understanding of a page in a book.

  10. What are some metaphors used on the Web?

    Other metaphors include: browsing, maps, bookmarks, forms, even the word Web itself.

    People had varying opinions about: surfing, windows, ...