Navigation Strategies
The way users navigate through a hyperdocument does not only depend
on their interest and on the information they find in the nodes.
Different users follow a different strategy, which is either "prudent"
or more "daring". Prudent users explore the neighborhood of the node
they start from before moving further away. This strategy is called
breadth-first navigation. The "daring" dive into the hyperdocument,
moving further and further away by following links (forwards) and only
backing out when they reach a node with no outgoing links. This strategy
is called depth-first navigation.
Actual users use a browsing strategy in between breadth-first and depth-first
navigation. Both the content of the hyperdocument and the embedded links
may suggest deviations from either strategy.
The experiments by De Vocht [DeVocht-94]
distinguish the following browsing strategies:
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Breadth-first navigation is achieved by first visiting all nodes
that are only one link away from the "starting" node, (following the link
to such a node, reading it, and backing out to the starting node).
-
Depth-first navigation is achieved by following links to nodes
further and further away from the "starting" node. Only when a node with
no outgoing links is reached the path is followed backwards until a new
(forward) link is found.
-
Random navigation is when nodes are visited in random order (in an
order which doesn't relate to the structure of the hyperdocument, except
that only nodes are chosen to which a link exists from the nodes that were
visited before. Basically this means that the user builds a list of possibly
interesting nodes to visit (judging from the links leading to them).
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A number of variations on both the breadth-first and the depth-first strategy
can be considered,
which differ in they way they limit the number of outgoing links that are
considered per node.
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Strategy 1 uses a fixed portion of the number of outgoing links
per node.
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Strategy 2 uses a fixed number of outgoing links per node.
-
Strategy 3 uses a random number of outgoing links per node.
-
A combination of depth-first and breadth-first is also possible: Strategy 4
does depth-first navigation up to a certain distance from the starting
node, and does breadth-first navigation from there on.