Hypermedia: Proceedings der Internationalen Hypermedia ’93 Konferenz, Zürich, 2./3. März 1993

248 Pages·1993·10.473 MB·German

by  Annelise Mark Pejtersen (auth.), H. P. Frei, P. Schäuble (eds.)

Informatik aktuell
Herausgeber: W. Brauer
im Auftrag der Gesellschaft fUr Informatik (GI)
H. P. Frei P. Schauble (Hrsg.)
Hypermedia
Proceedings
der Internationalen Hypermedia '93 Konferenz
Zurich, 2./3. Marz 1993
Springer-Verlag
Berlin Heidelberg New York
London Paris Tokyo
Hong Kong Barcelona
Budapest
Herausgeber
H. P. Frei
P. Schauble
Institut fUr Informationssysteme, ETH ZUrich
CH-8092 ZUrich
Programmkomitee:
A. Aders, Technikum Winterthur
R. Albrecht, Universitat Innsbruck
G. Coray, EPF Lausanne
R. Cordes, Telenorma Frankfurt
H. P. Frei, ETH ZUrich (Vorsitz)
N. Fuhr, Universitat Dortmund
W. Irler, Universita di Trento
W. Janko, WU Wien
G. Knorz, Fachhochschule Darmstadt
R. Kuhlen, Universitat Konstanz
H. Maurer, TV Graz und IMMIS Graz
J. Nievergelt, ETH ZUrich
B. Plattner, ETH ZUrich
W. Rauch, Universitat Graz
P. Schauble, ETH ZUrich
W. Schaufelberger, ETH ZUrich
H.-J. Schek, ETH ZUrich
N. Streitz, GMD-IPSI Darmstadt
P. Stucki, Universitat ZUrich
B. Teufel, ART, Ueberlingen
A. Ventura, UBILAB, SBG ZUrich
C. Womser-Hacker, Universitat Regensburg
CR Subject Classification (1992): H.3, H.S.I, H.S.2, 1.7.2, 1.1, 1.2, 1.3, 1.S
ISBN-13: 978-3-S40-S6477-S e-ISBN-13: 978-3-642-78086-8
DOl: 10.1007/978-3-642-78086-8
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Preface
The Hypennedia '93 is the fourth in a series of Hypertext/Hypennedia conferences
that have taken place in Basel, Dannstadt, and Graz. All these conferences--including
the Hypennedia '93--were jointly organized by the respective Special Interest Groups
of the Infonnation Technology Associations of Austria (OCG), Gennany (GI), and
Switzerland (SI).
The tenn hypermedia--as it is used at the present time--stands for infonnation that is
organized with links that connect portions of infonnation. At the same time, hyper
media signifies that these infonnation portions may be of an arbitrary medium type
like text, graphics, image, sound, video, or executable code. We also refer to 'pure' hy
pertext and to 'pure' multimedia as hypennedia. The former is of a uniform medium
type, namely text, and the latter may be arranged in a strictly linear way, i.e. without
links. Because we consider hypertext and multimedia as special cases of hypennedia,
we have called this conference simply 'Hypermedia'.
The international involvement has grown significantly since the last conference. The
preceding three conferences were predominantly for researchers from the German
speaking areas of Austria, Gennany, and Switzerland. This is still the case; however,
many researchers from non-Gennan speaking countries submitted papers success
fully. We are convinced that this will be an excellent opportunity for our researchers
to broaden their views, allowing them to compare their results against the work done
by researchers from other countries. As a consequence, this volume contains contri
butions from seven countries. Another consequence is that many papers are written
in English.
The principal purpose of the Hypennedia '93 and of these proceedings is to disclose
new and exciting research results. Even though we had this objective in mind, the
ubiquitous question is whether there are enough novel results to be presented at the
increasing number of hypennedia workshops and conferences. We never intended to
compete with the large international conferences such as the ACM Hypertext Con
ference that takes place every year, alternatively in Europe and the USA. We have
rather aimed for a small, yet exciting, conference to give the participants the op
portunity to communicate and discuss new ideas in a stimulating environment. At the
same time, we have tried our best to attract contributions for the Hypennedia '93 that
live up to international standards.
These proceedings are proof that this goal was achieved. A great number of papers
were submitted by many a project team. The reviewers performed a careful evalua
tion, and the program committee had to make the final decision of accepting or reject
ing a paper, a task which was not always easy. We would like to thank them all for
the excellent job they did.
VI
Also, we would like to thank everyone who contributed to the success of the
Hypermedia '93. This includes the program committee, the organizers, and in particu
lar Rita Jenny, Madeleine Bernard, and Silvia WertH. Without their assistance the
Hypermedia '93 would not have been possible. Last but not least, we thank
Sprlnger-Verlag for publishing these proceedings.
H.P.Frei P. Schauble
Zurich, March 1993
Inhaltsverzeichnis
A. M. Pejtersen (Invited Talk)
Designing Hypermedia Representations from Work Domain Properties
J. Pedersen (Invited Talk)
Computational Aids for Query Improvement 33
H. Schutt, J.M. Haake
Server Support for Cooperative Hypermedia Systems 45
Ch. Haser, A. Haake
The Hypermedia Presentation Composer:
A Tool for Automatic Hyperdocument Delivery 57
D. Stieger
Verbesserung der Kantenbeschreibung in Hyperkollektionen
durch Relevanzriickkoppelung 69
D. Reiter, D. Roller
Erschliessung von Information und Wissen:
Verfahren zur dynamischen Aggregation von Hypertrails 81
F. Maurer, G. Pews
Hypermedia als Zwischenrepriisentation bei der Expertensystementwicklung 93
M. Cadisch, A. Gloor, T. Kocsis, R. Burgin, E. Pretsch
A Knowledge-Based Hypermedia System for Molecular Spectroscopy 105
P. Purgathofer, T. Grechenig
Navigation in Hypertext by Browsing in Survey Objects 116
K. Andrews, F. Kappe
Strait-Jacketing Authors:
User Interface Consistency in Large-Scale Hypermedia Systems 130
U. Glavitsch, D. Knaus, J. Rentsch
Audiodokumente in Hypermedia-Informationssystemen 138
W. Herold, M. Millier
Ein Stufenindex als Navigationshilfe fUr Hypertextdokumente 150
K. Meusel, B. Schrocksnadl, J. Schiff
Orientierung und Navigation in strukturierten Hyperdokumenten 160
M. Henke
Hypermedia in der Medizin -
Die Gestaltung der digitalen Patientenakte als Hypermedium 172
VIII
H. Eirund, M. Hofmann
Designing Multimedia Presentations 183
U. Glowalla, J. Hasebrook, G. Hiifele
Implementation und Evaluation computerunterstiitzter Aus-und Wciterbildung
mit dem Hypermedia-System MEM 195
B.H. Thomas
Using a Language for Process Specification (ALPS) to Define Hypertext Trails 208
J. Gu, U. Thiel
Automatically Converting Linear Text to Hypenext: A Case Study 220
Short Contributions
V. Risak
Hypertext und nichtkonventionelle Textstrukturen 232
E. Griffiths
Flight Preparation with HyperCard 235
H.G. Klein
Hypertext in the Humanities: TERESA 238
Index of Contributors 241
Designing Hypermedia Representations from Work
Domain Properties
Annelise Mark Pejtersen
Ri~ National Laboratory
Dk 4000 Roskilde Denmark
This paper argues that associative, semantic networks in hypermedia systems cannot be based
only on the individual users' associative relationships as they occur during interaction with the
system. Instead they should be chosen to represent different semantic relationships and struc
tures derivedfrom an analysis of the properties oft he work domain, the task situation, and the
user characteristics, which constitute the predominant features of a work system. Such se
mantic relationships should be identified for the different perspectives of the work system in
order to support the user's activities at the different levels of representation at which the user
chooses to perform. In addition, the interface formats should allow different perception oft he
information presented as required by semantic analysis, associative problem solving, navigation
in the problem domain, and procedural interactions. This approach is illustrated with the Book
House hypermedia system for libraries.
1. Introduction
Hypermedia system design reflects an increased attention to the development of applications
for more complex work domains. From a start as a novel way of supporting information re
trieval and text processing and as the basis for experiments in conceptual issues related to re
search in a promising new technology, hypermedia designs have progressed into areas of soft
ware development, education and training, community information, museums etc. Currently
hypermedia systems are being developed for a variety of domains such as patent law, auditing,
post office work, business management, case handling. However, as will be shown below, all
these hypermedia designs are being introduced into domains which share common characteris
tics to a great extent.
Meyrowitz, (1989, 1992) Nielsen (1990), Romiszowski (1990) and many others put for
ward claims for systems with "interesting content" rather than hypermedia systems for the pur
pose of experimenting with hypermedia concepts. Since the latest developments have shown -
and hopefully will even more so in the future -a growing number of systems with "interesting
content", this paper discusses some of the analytical perequisites for rendering modem, com
plex, real world work domains representable in hypermedia systems. Shneidermann (1989)
suggests that hypermedia systems are particularly well suited for domains where a large body
of information can be organized into numerous, related fragments.
Many modern work domains are defined by a relatively high degree of information com
plexity. The size of the problem space and the number of different, potentially relevant factors
to take into account are large and often require simultaneous attention. At the same time, domain
information can be dynamically changing because of environmental influences. In complex and
unstable domains, rigourous rule-based task procedures have to be replaced by problem solv
ing, decision making and coordinating activities.This will give users more degrees offreedom
and fewer constraints regarding their possibilities for taking action. Users' discretionary, ex
plicit explorations of goals and constraints will be required in order to ensure that the system is
maintained within the boundaries of acceptable performance.
2
These tendencies and the accompanying needs for users to be able to explore actively the
domain constraints and goals require systems with hypermedia features. Support is required for
the identification of the degrees of freedom left for users' improvisations, associations and in
ventiveness as limited by the domain constraints. From this follows the idea of a transparent
system which directly makes visible to the users the network of domain relations and con
straints and encourages the utilization of the alternatives available for action depending on per
sonal characteristics and subjective preferences. However the prevailing need for support is
heavily dependent on the domain.
Secondly, studies of user performance in actual task situations have uncovered several dif
ferent forms for "natural decision making." Users in familiar situations are not likely to catego
rize or process multiple attributes of information in a normative way as system designers often
expect them to. Nor do they sequentially carry out a formal situation analysis, goal formulation,
priority judgment and planning (Klein 1989, Pejtersen 1984, Rasmussen 1986). Depending on
their expertise, they will resort to browsing and search within the context of their task environ
ment in the hope that they will recognize information matching their mental model of the case in
question. Without the need for a deep analysis of the information presented, users with some
training have the skill to directly perceive the meaning of the information and act upon it imme
diately (Rasmussen and Vicente 1990). From a different perspective, Bush's assumptions
about associative information processing being the most natural way for humans to solve prob
lems fit into these findings. (Bush 1945, Nyce and Kahn 1992).
An extension of this is that problem solving can take place at several levels of abstraction
ranging briefly from goal to functional to physical considerations. There is thus a need to ex
pand the initial hypermedia attention to associative recognition based information processing as
a unique natural approach to also include mUltiple levels of processing. Information about the
semantic relationships in the domain networks needs to be displayed in ways that support this
multi-modal type of analytical and associative information processing behaviour.
These features of user behaviour in modem work systems with their associated needs for the
exploration of domain constraints and action possibilities in network structures which are easily
perceptible at multiple levels will make the hypermedia concept an appropriate vehicle for many
system designs -also in domains which have not previously been considered.
2. Outline
The purpose of this paper is to put forward some arguments for the implementation of the
hypermedia concept in advanced system design for complex work domains. The basic assump
tion is that hypermedia is a cognitive concept (and only secondarily a particular category of
software) which was developed and implemented in a period when retrieval and control of in
formation was no longer feasible with traditional procedures due to the rapidly increasing com
plexity and amount of the information to be processed.
In addition the paper will demonstrate the growth in the development of hypermedia systems
during the last four years and indicate that this increase is limited to a relatively narrow variety
of domains and indeed has its peak domains possessing common characteristics. Some reasons
are given for this trend both in relation to the nature of the hypermedia concept and in relation to
the different characteristics of various work domains.
Thirdly, the paper suggests a framework for the design of hypermedia representations based
on an analysis of work system properties which can be useful for all kinds of domains. Without
such a framework, it is difficult to see how hypermedia designs can emerge from their present
limitations to applications in a restricted number of domains and thus achieve their deserved im
pact on new system developments. This framework also offers a solution to some of the most
frequently discussed problems in the hypermedia literature about how to overcome
users'"disorientation" and "cognitive overhead" (Conklin 1987). It is claimed that non-sequen-
3
tial, unconstrained associative behaviour is an efficient way of problem solving for skilled
users, but for users in unfamiliar situations, analytical, even sequential, reasoning on symbolic
structures is a more efficient problem solving behaviour.
Finally, the paper includes a running discussion of the Book House system designed for end
user..' information retrieval in libraries. It is used to exemplify how the framework for cognitive
work analysis presented in this paper was employed for empirical domain analyses in libraries
in the late 70's and the beginning of the SO's before hypermedia tools and concepts became
familiar. Although they were carried out independently of this technique, the studies identified
user behaviours which actually could only be adequately supported by hypermedia structures
and representations. Thus years of empirical studies of cognitive user behaviour based on a dif
ferent perspective pointed to a need for system features that actually turned out to be equivalent
to a hypermedia system concept. The strength of this concept was confirmed by a successful
user evaluation of the Book House in real life environments.
3. Hypermedia
The success of hypermedia systems is based on the concept of free and flexible navigation in
semantic relationships which enable the tailoring and design of connections and relationships
matching the semantics of the problem space with the semantics of users' cognitive worlds. It
allows the design of a rich, multidimensional resource envelope for mUltiple associative activi
ties as an alternative to the support of a particular normative interaction procedure. The strength
of hypermedia systems for representing information is the ability of links to explicitly represent
flexible semantic structures, and the ability of nodes to generate a natural correspondence be
tween objects in the world and the nodes in the hypertext database (Conklin 1987, Begoraj,
1990). Others see important features in the "non-linear access to information, varied informa
tion access, integrated information access, ease of access and free access of information"
(Duchastel, 1990).
There are numerous definitions of typical hypertextlhypermedia features which distinguish
hypermedia applications from another computer systems and place varying and selective em
phasis on their characteristics. From an artefacts point of view: "Windows on a screen associ
ated with objects in a database, and links provided between these objects, both graphically (i.e.
labelled as icons) and in the link database (i.e. as pointers)" (Conklin 1987). "Data stored in a
network of nodes connected by links" (Smith and Weiss,I988); as a design concept: "a set of
abstractions that provide a conceptua1 framework for creating, storing, retrieving information in
a hypermedia" (Leggett et ai, 1990); and finally from a pragmatic "look and feel" user point of
view "when users' interactively take control of a set of dynamic links among units of informa
tion" (Nielsen 1990). For the purpose of the present paper, which discusses the Book House
within a cognitive design framework and as an actual artefact. any of these and most other
definitions are equally representative.
The hypermedia language uses application-dependent terminology, but basically it consists
of nodes which are the single database entities containing the information content to be pro
cessed, stored, retrieved and of links connecting the attributes of node contents in graph struc
tures which are collections of nodes in a network which can be further divided into subcate
gories such as subgraphs or webs. Interaction with the database is enabled by navigating in
(part 00 the total network of nodes by browsing through links, keyword searching or browsing
through a selective collection of link and nodes in the network with a browser. and thus creat
ing individual user palhs. of associations.
Important for this discussion is that there are no constraints on nodes or semantic structures;
any assembly of nodes and links is possible; multiple structures are possible for the same con
tent information. It is possible to present and view content information from different perspec
tives and in different contexts; links and network structures can be easily modified. Thus a