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is known that browsing can help users to find the required documents when they have problems
with constructing a proper formal query. The size of hyperspace in regular IR hypermedia is
usually very large and can not be structured "by hand". It means that the links in this hyperspace
are not provided by a designer as in on-line information systems, but are calculated by the system
(for example, using similarity measurements). Another difference from on-line information
systems is that users of IR hypermedia are more often professionals in different areas who use the
system in their everyday work with different IR goals. A very new special kind of IR hypermedia
is IR systems on Word Wide Web which have slightly different nature in their links and a
potentially unlimited hyperspace. Existing adaptive IR systems (Kok, 1991) show some ways to
help the user in pure IR settings. Adaptive IR hypermedia systems can offer some additional help
by limiting the navigation choice (Boy, 1991; Mathé & Chen, 1996) and by suggesting the most
relevant links to follow (Armstrong et al., 1995; Kaplan, Fenwick & Chen, 1993; Katsumoto,
Fukuda & Shibata, 1996; Mathé & Chen, 1996).
Another new area of application for adaptive hypermedia is institutional information systems
which serves on-line all the information required to support the work of some institution, for
example, a hospital (Vassileva, 1996). Originally, these kinds of systems were developed as a set
of loosely related databases, but in some recent systems such databases are joined into a single
hyperspace which can be reasonably large. A specific feature of these systems is that they are a
medium for everyday work of many institution employees. According to their profession they may
always use only a specific area of hyperspace, and according to the current working goal they may
need an access to a very small subset of it. Most of users never need to access the parts of the
hyperspace outside their working area, moreover, too many navigation opportunities somewhat
distract them from their primary work. In this respect work-oriented institutional information
systems significantly differs from search-oriented IR hypermedia and on-line information systems
where the "working area" of a user is the entire hyperspace. At the same time users of institutional
information systems may need assistance in organizing a more convenient personalized access to
their working areas (Vassileva, 1996). Another problem of institutional information systems
which is similar to one of the problems of educational hypermedia is related to new employees
who are not familiar with the structure of the hyperspace (though they can be familiar with the
application domain itself) and can get lost even in their small professional subarea.
The last of the new application areas is systems for managing personalized views in
information spaces such as Information Islands (Waterworth, 1996) and Basar (Thomas, 1995).
Existing telecommunication systems such as World-Wide Web (WWW) offer huge amount of
different information and on-line services which form a really unlimited hyperspace. Many users
need to have an access too one or more subsets of all the hyperspace for their everyday work. To
protect themselves from the complexity of the overall hyperspace, they maybe interested to define
personalized views on the entire hyperspace. Each view can be devoted to one of the goals or
interests related with the work of the user. Partly, this application area is similar to institutional
hypermedia and other kinds of information systems where users need a convenient access to a
subset of an information space for everyday work. A new factor which affects systems dealing
with wide (and world-wide) information spaces is the dynamic character of hyperspace where
items can appear, disappear, or evolve. Personalized views in world-wide information spaces
require permanent management: searching for new and relevant items and identifying expired or
changed items (in this sense, this application area is similar to IR hypermedia). Adaptation to the
user goals, interests, and background can help to solve the identified problems (Thomas, 1995;
Thomas & Fischer, 1996).
It is worthwhile to stress again that all six listed application areas are not mutually exclusive.
Some of them are pairwise similar and share the same problems. These pairs are: IR hypermedia
and on-line information systems, on-line information/help systems and educational hypermedia,
educational hypermedia and institutional hypermedia, institutional hypermedia and information
space management systems. Also, the difference between neighboring areas is not always clear-cut
and some systems belong to both areas, for example, Hypadapter (Hohl, Böcker &
Gunzenhäuser, 1996) and HYPERCASE (Micarelli & Sciarrone, 1996) share features of
educational hypermedia and on-line information systems, and HYPERFLEX shares features of