From: langston@memstvx1.memst.edu (Mark C. Langston)
Newsgroups: alt.hypertext
Subject: Re: Interaction with a hypertext
Date: 6 Sep 92 22:46:48 -0600
Distribution: world
Organization: Memphis State University

  The recent discussion of active v. passive hypertexts (HT's) piqued my
interest.  I am doing R&D on educational hypertexts, and would like to 
incorporate the user into a more active role during navigation, along the
lines of annotation.  Several issues come to mind:

* If the HT structure is theory-determined or research-determined (as
  opposed to just thrown together, a very poor way to develop links),
  a strong indexing/inference engine would need to be incorporated into
  the sytem to correctly link user annotations/additions.

* If user after user after user annotates a particular HT, the possibility
  arises that most of the accesible information (via the HT) will become
  embedded in the annotations, and the HT will become redundant and linear.

* Allowing multiple annotations increases the amount of user-irrelevant
  material present on any one card or screen, and increases the linearity
  of the HT.

* Allowing multiple annotations increases the amount of material in general
  accessible from any one card, and again increases the linearity of the HT.


* Allowing dynamic node creation for indexing of end-user annotation opens the
  door to computational explosion on number of links.


How would one rectify these problems?  HT's in general are developed 'off-the-
cuff', with no empirical or theoretical basis (correct me if I'm wrong, it
would be welcome news).  If one assumes that the HT does have empirical/
theoretical foundations for links, a sensible approach would be the knowledge
annealing system addressed in a previous post.  However, one would hope that
the system could be more automated, and not require current updating by a
moderator.
  The other issues address the inherent nonlinear approach that HT's are 
designed to accomodate.  If one allows too many annotations, the nonlinearity
will become, at best, muddied, at worst, lost completely.  One could assume
unlimited storage/computational power, but I'm focussing on smaller systems.
  One could allow for dynamic node creation for each new annotation, with
links from the annotated card to the current annotation, referenced by
keyword.  This is fine if the HT under consideration is a standard card->
keyword->link to new card type.  However, these systems have an inherent
coherence problem, in that the end user has difficulty following the
coherence of the links between keyword/card, since these are based on the
programmer's assumptions of coherence, and not the user's.  
  If, however, an intermediary interface is implemented to allow the user
to coherently follow links (requiring a theoretical basis for knowledge
organization iand link structure in the HT, such as I have been working on)
the dynamic node creation scheme would tax the interface, requiring it to
either shoehorn the new node into a link structure implemented in the
coherence mechanism, or to create a new link type.  Again, this raises the
question of computational explosion among link types, and these whould be
kept at a fixed number.

  It almost seems that there is an interaction between:
    a) Number of links
    b) Types of link structures
    c) number of nodes
    d) node types
    e) coherence during link traversal
    f) dynamicism of said HT.

Without factor f), the problems are fully within the capacity of the system,
but once the HT becomes dynamic (from an end-user standpoint, someone unaware
of the theoretical basis of the HT organization), the computational power
required approaches that of natural-language understanding systems, and, I
fear, would work about as well.

Why not dump the theoretical basis of the HT?  Well, one could do this, but
the whole point of grounding such a system theoretically/empirically is to
facilitate search speed and accuracy, and to maintain user coherence, instead
of relying on the user to infer the programmer's reasons for coherence.

If anyone has done similar research, please email me, as I would be happy to
exchange papers/ideas.



-- 
+--------8<------Cut Here------8<------Cut Here------8<------Cut Here---------+
  Mark C. Langston   |  "Secrecy is the beginning of tyranny."                 
  Psychology Dept.   |  "Always listen to experts.  They'll tell you what can't
  Memphis State U.   |     be done, and why.  Then do it."                      
      "Pftph!"       |           -From the notebooks of Lazarus Long