Keith Andrews, Frank Kappe, and Hermann Maurer
Institute for Information Processing and Computer Supported New Media (IICM)
{kandrews,fkappe,hmaurer}@iicm.tu-graz.ac.at
Current networked information systems on the Internet, whilst
extremely successful, run into problems of fragmentation, consistency,
scalability, and loss of orientation. The development of "second
generation" networked information systems, such as Hyper-G and its
Harmony client, can help overcome these limitations. Of particular
note are Hyper-G's tightly-coupled structuring, linking, and search
facilities, its projection of a seamless information space across
server boundaries with respect to each of these facilities, and its
support for multiple languages. Harmony utilises two and
three-dimensional visualisations of the information space and couples
location feedback to search and link browsing operations, in order to
reduce the likelihood of disorientation.
Whilst traditional services such as electronic mail, remote login, and
file transfer still account for the bulk of traffic on the Internet,
by far the fastest growth is being experienced by networked
information systems like WAIS, Gopher, and above all the World-Wide
Web (WWW or W3). These systems, although having transformed the way
people perceive and interact with information resources on the net,
belong to the first generation of information systems on the Internet
[3]. They work well in particular
contexts but run into difficulties when applied to hundreds of
thousands of documents distributed over many thousands of
servers. They provide only a single structuring mechanism, no
graphical navigation aids, only rudimentary access control, little
support for automatic database maintenance, no scalable document
replication mechanisms for popular information, and little or no
built-in support for multiple languages. Furthermore, they are
"read-only", in the sense that information providers prepare data
which information consumers can generally only browse. Hyper-G is a
second generation [2] system designed to
transcend some of these limitations.
Hyper-G is a large-scale, distributed, multi-user, structured,
hypermedia information system, which runs as a client-server
application on the Internet [1]. Hyper-G is interoperable
with both Gopher and W3 clients and servers, but its data model is
much richer as can be seen in Figure 1. Documents may be
grouped into aggregate collections, which may themselves
belong to other collections and which may span multiple Hyper-G
servers, providing a unified view of distributed resources. A special
kind of collection called a cluster is used to form multimedia
and/or multilingual aggregates.
Hyperlinks in Hyper-G connect a source anchor within one
document to either a destination anchor within another
document, an entire document, or a collection. Links are not stored
within documents (as in W3) but in a separate link database: links are
not restricted to text documents, they can be followed backwards,
updated and deleted automatically when their destination moves or is
deleted (no "dangling links"), and are easy to visualise graphically.
Hyper-G has fully integrated search facilities: every document and
collection is automatically indexed upon insertion into the database
- no extra indexing steps are required. Both attribute (author,
title, keywords, etc.) and full text (content) searches are supported,
including boolean combinations and term truncation. Searches may be
restricted in scope to particular sets of collections which may span
multiple servers.
Both anonymous and identified users are supported, with access rights
assignable on a per document or per collection basis to user groups or
individual users. Identified users have "home collections" within
which to organise personal documents and keep pointers to resources.
Figure 2: Harmony Client for X Windows
Harmony is the Hyper-G client for X Windows on Unix platforms (see
Figure 2. It has native document viewers for text, images, MPEG films,
audio, 3D scenes, and PostScript, including full hyperlink activation
and editing and document uploading. To help users orient themselves,
Harmony provides location feedback - the location of
documents or collections found by searching or hyperlinks is
automatically displayed in the collection browser, giving users a
sense of the context of an object prior to any decision to view it. As
a further aid to orientation, the link neighbourhood of a document may
be visualised using Harmony's local map. Harmony is also
multilingual: its user interface adjusts dynamically to the language
of first choice, documents available in multiple languages are
selected in order of language preference, and searches are optionally
language-dependent.
Figure 3: Harmony 3D Viewer and Landscape
A further innovative feature of Harmony is its use of 3D
visualisations (see Figure 3), both hand-crafted and automatically
generated. Model description files representing arbitrarily complex
scenes or objects are displayed by the Harmony 3D Scene Viewer;
Harmony's Information Landscape is an interactive, three-dimensional
visualisation of the collection structure.
In addition to the Harmony client descibed here, users may use any
other native Hyper-G client (such as hgtv for Unix VT100-style
terminals and Amadeus for MS-Windows), or any W3 or Gopher client to
access information on a Hyper-G server. Further information about
Hyper-G and Harmony and installation details may be retrieved by
anonymous ftp from
ftp://ftp.iicm.tu-graz.ac.at/pub/Hyper-G/ or from
the IICM Information Server under
http://info.iicm.tu-graz.ac.at/.
1.
Andrews, K. and Kappe, F.
Soaring Through Hyperspace,
in Proc. of Eurographics Symposium on Multimedia/Hypermedia in Open
Distributed Environments (June 1994), Graz, Austria, pp. 181-191.
Springer.
2.
Andrews, K., Kappe, F., Maurer, H., and Schmaranz, K.
On Second Generation Hypermedia Systems.
Journal of Universal Computer Science 0,0
(Pilot Issue, Nov. 1994), 127-135.
Available at
http://info.iicm.tu-graz.ac.at/Cjucs_root
3.
Fenn, B. and Maurer, H.
Harmony on an Expanding Net.
Interactions 1,4 (Oct. 1994), 26-38. ACM.
Abstract
Keywords:
hypermedia, information retrieval, information
visualisation, graphical interaction, Internet.
Introduction
HYPER-G
HARMONY
References
