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HYPER Tables of Contents: 87899191Z9393X93Y93Z969797X9899

Proceedings of ACM Hypertext'91 1991-12-15

Fullname:Proceedings of ACM Hypertext'91 Conference
Editors:Jan Walker
Location:San Antonio, Texas
Dates:1991-Dec-15 to 1991-Dec-18
Publisher:ACM
Standard No:ACM ISBN 0-89791-461-9; ACM Order Number 614910; ACM DL: Table of Contents hcibib: HYPER91
Papers:42
Pages:508

Proceedings of ACM Hypertext'91 -- Posters 1991-12-15

Fullname:ACM Hypertext'91 Conference -- Posters
Editors:Gary Perlman
Location:San Antonio, Texas
Dates:1991-Dec-15 to 1991-Dec-18
Publisher:ACM
Standard No:hcibib: HYPER91Z
Papers:22
Pages:22
  1. Plenary Address
  2. Real-World Issues
  3. Discovering Structure I
  4. Presentation Issues
  5. Construction and Authoring
  6. Malleable Structure
  7. Discovering Structure II
  8. Academic Hypertext
  9. Hypertext -- Integrative Issues
  10. Panels
  11. Technical Briefings
  12. Videos

Plenary Address

Cognitive Overheads and Prostheses: Some Issues in Evaluating Hypertexts BIBAKPDF 1-12
  Patricia Wright
There are many criteria for evaluating hypertexts. Adequacy and cost effectiveness are perhaps the most obvious from the producer's perspective; additional criteria are important for users. Examination of the limitations of various assessment criteria highlights the twin issues of the cognitive costs and benefits experienced by the using hypertexts as part of some other task. Many interface characteristics can contribute to readers' cognitive overheads. There is evidence that even changing screens to access information only a click away can impair memory processes. Fortunately, because hypertexts are computer-based, readers can call upon a variety of aids to support their cognitive activities, particularly memory and planning processes. The novelty of some of these prostheses raises questions about the literacy skills that hypertext readers may need. Studies of factors influencing readers' strategic decisions about using memory aids are discussed, together with their implications for hypertext design. It is concluded that hypertext evaluation requires a richer understanding of the cognitive entailments of working with information. But hypertexts, having highlighted the problems of cognitive costs, have the potential for offering readers the means of reducing these overheads not just for hypertext use but for many tasks that involve working with information.
Keywords: Cognition, Design, Memory, Planning, Reading, Tools

Real-World Issues

Industrial Strength Hypermedia: Requirements for a Large Engineering Enterprise BIBAKPDF 13-24
  Kathryn C. Malcolm; Steven E. Poltrock; Douglas Schuler
Current hypermedia tools do not support the needs of collaborative work groups in distributed heterogeneous environment and cannot be integrated into the existing and planned computing environment at large enterprises like Boeing. It is in meeting these needs, however, that hypermedia could make its greatest impact. Hypermedia systems must evolve beyond their current standalone status into a technology that is truly integrative. We use a description of some current hypermedia projects and a representative future scenario to help identify technical requirements and strategies for developing and deploying hypermedia that is of sufficient "industrial strength" to support a large engineering enterprise. This paper is addressed to hypermedia researchers and developers as well as to our colleagues in other business and engineering organizations. The intent of this paper is to remind both the research and development communities of the urgent, "real-world" needs that exist and to encourage dialogue between the two worlds.
Keywords: Engineering applications, Requirements, Interoperability, Deployment
Using Hypertext in Selecting Reusable Software Components BIBAKPDF 25-38
  Michael L. Creech; Dennis F. Freeze; Martin L. Griss
Recently, there has been increasing interest in software reuse as a way to improve software quality and productivity. One of the major problems with reusing libraries of software components is helping users effectively select (find and understand) components of interest. This paper explores the use of hypertext to enhance the process of component selection through a prototype system called Kiosk. Included are discussions of the selection process, why hypertext is well suited for supporting selection, and important characteristics of hypertext systems intended to support reuse. Also discussed are how reusable libraries can be structured using hypertext, how such libraries can be mechanically built, and how their use enhances the component selection process.
   Kiosk consists of an open set of tools that can created, browse, and modify nodes and links in a software library. One of these tools, Cost++, can automatically generate a linked structure for libraries by clustering workproducts into components, and then placing components into multiple classification hierarchies. The Kiosk browsing tools allow users to peruse the components in libraries, examine library structures from multiple perspectives, and add new links and nodes to enhance the standard library structure.
Keywords: Software reuse, Software libraries, Component selection, Hypertext, Kiosk
Intellectual Property Rights for Digital Library and Hypertext Publishing Systems: An Analysis of Xanadu BIBAPDF 39-50
  Pamela Samuelson; Robert J. Glushko
Copyright law is being applied to works in digital form. The special character of digital media will inevitably require some adjustments in the copyright model if digital libraries and hypertext publishing environments are to become as commercially viable as the print industries have been. An intellectual property system works only when it embodies a reasonably accurate model of how people are likely to behave, but it is hard to predict author and reader behavior in an environment that has yet to be built. By far the most ambitious proposal for a digital library and hypertext publishing environment is Ted Nelson's Xanadu system. This paper reviews the intellectual property scheme in Xanadu and contrasts it with current copyright law. Xanadu's predictions about reader and author behavior are examined in light of how people currently behave in computer conferencing, electronic mail, and similar existing systems. These analyses identify some respects in which intellectual property systems might have to be changed to make digital libraries and hypertext publishing systems viable.

Discovering Structure I

Indexing Hypertext Documents in Context BIBAKPDF 51-61
  Guy A. Boy
To generate intelligent indexing that allows context-sensitive information retrieval, a system must be able to acquire knowledge directly through interaction with users. In this paper, we present the architecture for CID (Computer Integrated Documentation), a system that enables integration of various technical documents in a hypertext framework and includes an intelligent browsing system that incorporates indexing in context. CID's knowledge-based indexing mechanism allows case-based knowledge acquisition by experimentation. It utilizes on-line user information requirements and suggestions either to reinforce current indexing in case of success or to generate new knowledge in case of failure. This allows CID's intelligent interface system to provide helpful responses, even when no a priori user model is available. Our system in fact learns how to exploit a user model based on experience (from user feedback). We describe CID's current capabilities and provide an overview of our plans for extending the system.
Keywords: Contextual indexing, Information retrieval, Tailorable system, Context acquisition, Hypertext
Identifying Aggregates in Hypertext Structures BIBAKPDF 63-74
  Rodrigo A. Botafogo; Ben Shneiderman
Hypertext systems are being used in many applications because of their flexible structure and the great browsing freedom they give to diverse communities of users. However, this same freedom and flexibility is the cause of one of its main problem: the "lost in hyperspace" problem. One reason for the complexity of hypertext databases is the large number of nodes and links that compose them. To simplify this structure we propose that nodes and links be clustered forming more abstract structures. An abstraction is the concealment of all but relevant properties from an object or concept.
   One type of abstraction is called an aggregate. An aggregate is a set of distinct concepts that taken together form a more abstract concept. For example, two legs, a trunk, two arms and a head can be aggregate together in a single higher level object called a "body." In this paper we will study the hypertext structure, i.e., the way nodes are linked to each other in order to find aggregates in hypertext databases. Two graph theoretical algorithms will be used: biconnected components and strongly connected components.
Keywords: Hypertext, Structural analysis, Graph theory, Abstraction, Aggregation, Generalization
Implementing Hypertext Database Relationships through Aggregations and Exceptions BIBAKPDF 75-90
  Yoshinori Hara; Arthur M. Keller; Gio Wiederhold
In order to combine hypertext with database facilities, we show how to extract an effective storage structure from given instance relationships. The schema of the structure recognizes clusters and exceptions. Extracting high-level structures is useful for providing a high performance browsing environment as well as efficient physical database design, especially when handling large amounts of data.
   This paper focuses on a clustering method, ACE, which generates aggregations and exceptions from the original graph structure in order to capture high-level relationships. The problem of minimizing the cost function is NP-complete. We use a heuristic approach based on an extended Kernighan-Lin algorithm.
   We demonstrate our method on a hypertext application and on a standard random graph, compared with its analytical model. The storage reductions of input database size in main memory were 77.2% and 12.3%, respectively. It was also useful for secondary storage organization for efficient retrieval.
Keywords: Hypertext database, Physical database design, Database clustering, Overview diagram, Aggregation, Exception

Presentation Issues

Screen Management in Hypertext Systems with Rubber Sheet Layouts BIBAKPDF 91-105
  Marc Kaltenbach; Francois Robillard; Claude Frasson
This paper addresses the issue of screen management in hypertext systems. It presents a new way of placing windows, or any graphical object delimited by rectangular boundaries, in the context of an existing set of windows. The heart of the technique presented is a particular re-scaling of the display which changes the locations of objects while maintaining their sizes and avoiding object overlapping. This functionality has uses both for authoring and browsing hypertext documents. In particular it enables the display of hierarchically structured information at various levels of detail and complements other visual graph management functions. More generally, the objective is to attenuate the feeling of disorientation users experience when related informations obtained through hypertext browsing are stacked upon a display screen. This work suggests extending hypertext systems by enabling users to create well structured information "collages" and to program animated presentations on the basis of browsing through ill or differently structured collections of documents.
Keywords: Collage, Graph, Hypertext, Motion picture, Rubber sheet layout, Scale factor, Tack point
CYBERMAP: Yet Another Way of Navigating in Hyperspace BIBAKPDF 107-121
  Peter A. Gloor
By integrating dynamic linking and automatic link generation into the automatic generation of an overview map we get a unique tool for navigation in hyperspace. We introduce the concept of HYPERDRAWERs to get a means for the partitioning of nodes in ordered sequences. CYBERMAP either complements existing navigational aids for hyperdocuments or provides a self sufficient navigation tool for browsing in a document. In addition CYBERMAP offers the capability of horizontal growth and easy hypertextualization of non-hypertextual documents without restricting the use of already installed browsing mechanisms besides CYBERMAP.
Keywords: Overview map, Automatic link generation, Dynamic linking, Fish eye views, Hypertext conversion, Navigation in hyperspace
Flying Through Hypertext BIBAPDF 123-132
  Patrick Lai; Udi Manber
Hypertext systems provide links between different pieces of information (text, figures, pictures, etc.) so that the reader can follow many different paths corresponding to lines of thoughts, levels of description, levels of details, and so on. One of the main problems in using hypertext systems is the navigation problem [Ni90a]. Users tend to get lost partly because the information they are reading can have a complicated structure which is usually unknown to them. We study in this paper a technique to help users orient themselves by a quick browsing, which we call flying, through hypertext.
   The first thing many people do when given a new book is flip through the pages to get a first impression of the book. Quite a bit of information can be gained by this quick informal evaluation. First, just the size of the book is a good indicator. A ten-page brochure is treated differently than a 500-page instruction manual. The book's density (how many characters per page), its layout (e.g., the font, the percentage of pictures), the technical content (e.g., number of equations, number of technical drawings), familiar features (e.g., pictures or drawings that the reader has seen elsewhere), just to name a few simple things that can be determined quickly, all give us important information about the book without reading even one sentence. This kind of information is not immediately available in hypertext, and we believe that the lack of it contributes to the navigation problem. We would like to provide this type of information in a quick and flexible way.
   We describe in this paper a tool for flying through hypertext systems and discuss the issues involved in its implementation. Our tool is analogous to flipping the pages of a book with one notable exception: the flipping is not necessarily in a linear order. The variability of the links and the structure that they provide enable flexible flipping in many different orders controlled by the reader. The key to any flipping is speed. The goal is not to digest the contents of the pages, but rather to gain some insight to features such as organization, size, depth, level, detail, and so on. Another analogy is to seeing a movie, or better yet a videodisk, in fast forward. There are certain characteristics of the movie that can be studied better that way. Flying can also be used to move fast from one place to another in the hypertext following a certain order or traversal. Flying is not intended to replace any of the other navigation tools; it is an additional tool.
Hyperspeech: Navigating in Speech-Only Hypermedia BIBAPDF 133-146
  Barry Arons
Most hypermedia systems emphasize the integration of graphics, images, video, and audio into a traditional hypertext framework. The hyperspeech system described in this paper, a speech-only hypermedia application, explores issues of navigation and system architecture in an audio environment without a visual display. The system under development uses speech recognition to maneuver in a database of digitally recorded speech segments; synthetic speech is used for control information and user feedback.
   In this research prototype, recorded audio interviews were segmented by topic, and hypertext-style links were added to connect logically related comments and ideas. The software architecture is data driven, with all knowledge embedded in the links and nodes, allowing the software that traverses through the network to be straightforward and concise. Several user interfaces were prototyped, emphasizing different styles of speech interaction and feedback between the user and machine. In addition to the issues of navigation in a speech only database, areas of continuing research include: dynamically extending the database, use of audio and voice cues to indicate landmarks, and the simultaneous presentation of multiple channels of speech information.

Construction and Authoring

Hypermedia Templates: An Author's Tool BIBAKPDF 147-160
  Karen Smith Catlin; L. Nancy Garrett; Julie A. Launhardt
Recently Brown University's Institute for Research in Information and Scholarship (IRIS) extended Intermedia to allow authors to define Hypermedia Templates -- sets of pre-linked documents which can be duplicated. Templates facilitate the creation of consistent hypermedia collections by automating what can be a laborious task: making documents and forging links manually.
   In this paper we discuss the Hypermedia Templates project. We first describe a collection of Intermedia materials that has been electronically published and explain the information design principles that were applied to it. We point out some general principles for building consistent hypermedia collections and discuss how these were reflected in the list of features for Hypermedia Templates. We then describe a user's interaction with a prototypical Hypermedia Template, as well as details of the user interface that we have built to provide template functionality in Intermedia. Finally, we identify some key features that would be important components of any next-generation template software.
Keywords: Hypermedia templates, Hypermedia design principles, Intermedia
What's Eliza Doing in the Chinese Room? Incoherent Hyperdocuments -- and How to Avoid Them BIBAKPDF 161-177
  Manfred Thuring; Jorg M. Haake; Jorg Hannemann
Research on understanding linear texts has shown that comprehension and navigation mainly depend on the reader's ability to construct a coherent mental representation. While the author of a traditional document can use a variety of structural cues to support his readers in building up such a representation, the author of a hyperdocument faces a new problem. If he wants to ensure that his readers understand the entire hyperdocument as a coherent entity, he needs means to indicate its structure in a comprehensible way. In this paper, we propose a construction kit which provides dedicated design objects for this purpose. The design objects can be characterized as building blocks for three functionally different components of a hyperdocument: its content part, organizational part, and presentation part. In addition to the design objects, we propose some design rules which should guide the construction of coherent hyperdocuments.
Keywords: Design of hyperdocuments, Coherent hyperdocuments, Rhetorics of hypertext, Hyperdocument construction kit, Labelled links, Composite nodes, Navigation, Comprehension of hyperdocuments
ABC: A Hypermedia System for Artifact-Based Collaboration BIBAPDF 179-192
  John B. Smith; F. Donelson Smith
Our project is studying the process by which groups of individuals work together to build large, complex structures of ideas, and we are developing a distributed hypermedia system to support that process. This description includes a brief overview of the system, but emphasizes three components: a hypermedia data management system or graph server, a set of browsers for working with graph objets, and a set of applications for working with data contents of graph nodes. A number of research issues are raised and discussed in context, including: composite objets; anchored links; scaling up for large applications; partitioning the hypermedia graph; consistency and completeness across subgraphs; and an open, extensible architecture for applications.

Malleable Structure

The Nested Context Model for Hyperdocuments BIBAPDF 193-201
  Marco A. Casanova; Luiz Tucherman; Maria Julia D. Lima; Jose L. Rangel Netto; Noemi Rodriguez; Luiz F. G. Soares
This paper describes the nested context model, a conceptual framework for the definition, presentation and browsing of documents. The model carefully combines hypertext links with the concept of context nodes, used to group together sets of nodes. Context nodes can be nested to any depth and, thus, generalize the classical hierarchical organization of documents. The nested context model also defines an abstract and flexible application program interface that captures the idea that different applications may observe the same node in different ways. Finally, the model offers a rich set of operations to explore the double structure of a hyperdocument - that defined by the links and that induced by the nesting of context nodes.
Issues in Modeling a "Dynamic" Hypertext Interface for Non-Hypertext Systems BIBAKPDF 203-217
  Michael Bieber
Many hypertext systems are primarily "static" systems that were designed specifically to apply a hypertext interface to a particular domain. For us, hypertext is a tool for augmenting "dynamic", non-hypertext information systems such as decision support systems and expert systems. Many information systems require a dynamic implementation of hypertext, one that relies primarily on virtual structures and computation to generate a hypertext network in real time. This paper explores the demands our dynamic view of hypertext makes on hypertext standards from two angles. First, what coordination is necessary to establish a dynamic hypertext interface to an arbitrary front-end or back-end information system? Here we introduce the concept of bridge laws to map application components to hypertext structures. Second, how does a dynamic view of hypertext affect document interchange among hypertext systems and between a hypertext and non-hypertext systems?
Keywords: Hypertext computation, Hypertext virtual structures, Bridge laws, Decision support systems, Information systems, Document interchange, Knowledge-based system shell architecture
Dynamic Adaptation of Hypertext Structure BIBAKPDF 219-231
  P. David Stotts; Richard Furuta
A technique is described for adapting the apparent structure of a hypertext to the behavior and preferences exhibited by its users while browsing. Examples are given an implementation of this technique using the timing mechanism in Trellis. In the technique, event durations in a document are altered without actually changing the links in the underlying Petri net. The two extrema of instantaneous events and infinite delays can be used to create apparent node and link deletions and additions, as well as to insert new tokens (loci of activity) into a document. Adaptation of these times is accomplished using a simple data state in which the event timings (and other document properties) are variables, called attributes. As a reader traverses hypertext links, author-supplied adaptation agents are invoked to collect information and possibly change the values of the attributes. Agents encapsulate and effect the criteria for deciding when, and specifically how, a structure should be adapted. Several practical examples illustrate the conclusion of this report: sophisticated alterations do not require a complicated adaptation mechanism, that changing document constants into document variables provides flexibility to this mechanism, and that using a limited simple mechanism is the only hope for retaining analysis of the static and dynamic net properties.
Keywords: Hypertext, Trellis, Petri nets, Place/transition nets, Browsing semantics, Adaptation, Parallel computation model, Timing

Discovering Structure II

Don't Link Me In: Set Based Hypermedia for Taxonomic Reasoning BIBAKPDF 233-242
  H. Van Dyke Parunak
Hypermedia is often described as nodes of information with links between them, suggesting the conceptual model of a graph. A broader definition is a system of nodes of information through which people can move nonlinearly. Such a definition, while including graph-based hypermedia, also allows alternative implementations. This paper illustrates the need for alternative models by exhibiting a particular reasoning task for which navigating among nodes by way of explicit links is less effective than an alternative model of intersecting sets of nodes. The task is taxonomic reasoning, a particular kind of reasoning task that deals with the comparison and classification of highly similar nodes, in which an analyst viewing one node thinks not in terms of linking it to another node, but of including it in or excluding it from a set of related nodes.
   This paper discusses this kind of reasoning and describes HyperSet, a set-based hypermedia system designed to support it. It compares HyperSet with other tools that support taxonomic reasoning, discusses the formal and implementational relationships between graph-based and set-based hypermedia, and defines the features that are required in a hybrid system that can concurrently support both set and graph manipulations.
Keywords: User models, Taxonomic reasoning, Interfaces, System architectures
Architectures for Volatile Hypertext BIBPDF 243-260
  Mark Bernstein; Jay David Bolter; Michael Joyce; Elli Mylonas
Aquanet: A Hypertext Tool to Hold Your Knowledge in Place BIBAPDF 261-275
  Catherine C. Marshall; Frank G. Halasz; Russell A. Rogers; William C., Jr. Janssen
Hypertext systems have traditionally focused on information management and presentation. In contrast, the Aquanet hypertext system described in this paper is designed to support knowledge structuring tasks. Aquanet is a browser-based tool that allows users to graphically represent information in order to explore its structure. In this paper, we discuss our motivations for developing Aquanet. We then describe the basic concepts underlying the tool and give an overview of the user interface. We close with some brief comments about our initial experiences with the tool in use and some of the directions we see the Aquanet research moving in the near future.

Academic Hypertext

The Pedagogy of Computing: Hypermedia in the Classroom BIBAKPDF 277-289
  Charles Ess
I describe how I have used IRIS Intermedia, a sophisticated hypermedia program, in teaching an upper-level class on the emergence of philosophy and science in the context of religious story and material culture. I first describe the program and summarize the pedagogical results of using the program as documented at Brown University. I then describe various uses of the program in the Drury class, and the observed impacts of these uses. Our experience with hypermedia at Drury College both corroborates and extends the pedagogical impacts of hypermedia already documented at Brown University, especially in terms of dramatically increasing student mastery of difficult material, and student involvement in the course through collaborative learning strategies supported by hypermedia resources distributed across a network. These pedagogically desirable benefits, however, are accompanied by concerns regarding "fragmentation" and "decentering" in student work in hypermedia, and regarding ethical irresponsibility towards shared and thus vulnerable resources.
   These results are especially significant as they demonstrate that instructors with relatively limited resources can nonetheless reap dramatic pedagogical benefits from hypermedia technologies in the classroom. This also means: relatively exotic hypermedia technologies may successfully migrate to the resource-limited classrooms of smaller colleges and universities.
Keywords: Hypertext, Hypermedia, IRIS intermedia, History of philosophy, History of science, Pedagogy, Collaborative learning, Electronic conferencing, Electronic journaling, Computer ethics, Postmodernism
Beyond the Electronic Book: A Critique of Hypertext Rhetoric BIBPDF 291-298
  Stuart Moulthrop
Hypertext for the Electronic Library? CORE Sample Results BIBAKPDF 299-312
  Dennis E. Egan; Michael E. Lesk; R. Daniel Ketchum; Carol C. Lochbaum; Joel R. Remde; Michael Littman; Thomas K. Landauer
The Chemistry Online Retrieval Experiment, or CORE project, is studying the possibility of creating a useful, usable electronic library for chemistry researchers. In a preliminary study, chemists were observed performing five different tasks representative of typical uses of the scientific journal literature. The tasks simulated browsing journals, answering specific questions given a citation to an article, answering specific questions given no citation, writing essays to summarize and integrate information, and finding "analogous transformations" for chemical reactions. Chemists carried out these tasks using one of three systems: (a) the printed journals supplemented with a widely used printed index system, (b) a hypertext system (the SuperBook document browser), or (c) a new electronic system (Pixlook) that incorporates traditional document retrieval methods plus full text indexing and delivers bitmap images of journal pages. Both electronic systems had a large advantage over the printed system for search and essay tasks. SuperBook users were faster and more accurate than Pixlook users at finding information relevant to browsing and search topics. Certain SuperBook hypertext features, however, did not work as well as Pixlook for displaying target articles. The patterns of data and log files of subjects suggest how SuperBook, Pixlook and related systems might be improved.
Keywords: Evaluation, Information retrieval, Hypertext design

Hypertext -- Integrative Issues

HDM -- A Model for the Design of Hypertext Applications BIBAPDF 313-328
  Franca Garzotto; Paolo Paolini; Daniel Schwabe
We present the latest developments of HDM, a design model for Hypertext Applications. The basic features of HDM are the representation of applications through several design primitives: typed entities composed of hierarchies of components; different perspectives for each component; units corresponding to component-perspective pairs; bodies representing the actual content of the units; structural links, binding together components or sub-entities of the same entity; typed application links, interconnecting components belonging to different entities; and a specific browsing semantics based on anchors, as a way to activate many different link types from within a unit.
   The development of HDM is part of the HYTEA project, carried on by a European consortium, aiming at the development of a set of authoring tools for an "engineered" development of Hypertext-Hypermedia applications. A HYTEA application is made by an HDM schema and an HDM Hyperbase (i.e., a set of instances). The basic HDM has already been shown to be translatable, either manually or through a compiler, into a node-and-link model ("a la DEXTER model"; the translated application can be targeted on several implementation tools (i.e., standard Hypertext tools already available on the market). HDM has already been used to develop a (small number) of applications, and to describe preexisting applications. These experiments have shown the need for improvements that are discussed in the paper: aggregate entities; sharing of components; is-a relationships and inheritance between entity types; sharing of bodies; structured access and "guided tours"; use of active media (animations and video-clips).
Using Structured Types to Incorporate Knowledge in Hypertext BIBAKPDF 329-343
  Jocelyne Nanard; Marc Nanard
It has been shown that the famous problem of user disorientation in hypertext is not due to the concept of hypertext itself but rather generally results from the lack of a conceptual model for hypertext application. Unfortunately, in most hypertext systems, the weakness of structure specification mechanisms discourages the development and use of such a model since it is difficult to reinforce hypertext structure and to really incorporate knowledge. A lot of works provide intelligent mechanisms to help navigation but either they use external knowledge or automatically synthesize links from information included in nodes which thereby have no sufficient conceptual value.
   The present paper focuses on an object-oriented hypertext model (implemented in the MacWeb system) using structured types to incorporate knowledge in hypertexts. Concepts and their relationships as well as their instances and their own relationships may be represented. Such a model makes the capture of knowledge at source easier thus allowing a more conceptual navigation. Furthermore, active behaviors may be associated, as methods, to types. This provides a powerful mechanism to help develop structured hypertext as well as task centered applications, by taking advantage of knowledge representation.
Keywords: Structured types, Knowledge representation, Object-oriented, Hypertext model, Document synthesis
Hypertext and Structured Object Representation: A Unifying View BIBAKPDF 345-358
  Hermann Kaindl; Mikael Snaprud
This paper addresses combining hypertext with knowledge representation as used in knowledge-based systems. Hypertext imposes explicit structure on text, whereas certain knowledge representation formalisms of AI are designed for structuring knowledge. We propose a way of tightly integrating hypertext and structured object representation, using (AI) frames for the basic representation of hypertext nodes. Moreover, we allow for the additional option of explicit representation of structure using partitions of hypertext nodes, which are realized as slots. In order to make the text more dynamic, our approach facilitates some aspects of object-oriented programming using message passing from the text in the browser.
   The proposed tight integration is useful for design tasks, in particular for building knowledge-based systems. According to our experience, hypertext provides a useful intermediary representation of knowledge between informal and formal. Based on a level of basic hypertext functionality, we provide several features useful for supporting knowledge acquisition. As an example of our results of using this method of knowledge acquisition, we illustrate the strategic knowledge in our application domain. In addition, tight integration supports important aspects of software engineering and the user interface. Moreover, we discuss several advantages from a hypertext point of view. In particular, the partitions of hypertext nodes can be useful for selective inheritance of text. In summary, both AI and hypertext will benefit from such a tight integration.
Keywords: Hypertext, Frames, Knowledge representation, Knowledge-based systems, Knowledge acquisition

Panels

The Nielsen Ratings: Hypertext Reviews BIBPDF 359-360
  Jakob Nielsen; Lynda Hardman; Anne Nicol; Nicole Yankelovich
From Memex to Hypertext: Understanding the Influence of Vannevar Bush BIBPDF 361
  Paul Kahn; James M. Nyce; Tim Oren; Gregory Crane; Linda C. Smith; Randall Trigg; Norman Meyrowitz
Structure, Navigation, and Hypertext: The Status of the Navigation Problem BIBPDF 363-366
  Mark Bernstein; Peter J. Brown; Mark Frisse; Robert Glushko; George Landow; Polle Zellweger
When Worlds Collide -- Reconciling the Research, Marketplace, and Applications Views of Hypertext BIBPDF 367-368
  Robert Glushko; David Gunning; Ken Kershner; Catherine Marshall; Louis Reynolds
The Role of Hypertext for CSCW Applications BIBPDF 369-377
  Norbert Streitz; Frank Halasz; Hiroshi Ishii; Tom Malone; Chris Neuwirth; Gary Olson

Technical Briefings

Hypertext and Pen Computing BIBAPDF 379
  Norman Meyrowitz
Some of the original goals of hypertext were accessibility, seamlessness, and connectivity. Yet most implementations of hypertext are still bound to large, immobile workstations, are operated with keyboards and mice and a reasonably complex interface, and are often focused on standalone, rather than connected, tasks.
   With the advent of pen-computing, we are beginning to see linking as a fundamental operating system and user interface component. In GO's PenPoint operating system, any selection in any notebook page can be linked to a selection on another page through the means of a simple pen gesture. The ability to create and follow links with a mere gesture creates a new level of accessibility to hypertext.
   Similarly, applications built on PenPoint are exploiting the pen interface for new generations of electronic book technology, in which browsing and search for information can be done without keyboard and mouse, in which annotation can be done with computerized "ink" and in which remote, wireless connectivity serves as a major new component.
   The demonstration will show each of these technologies and explain the fundamental basis behind each of these technologies.
Storyspace as a Hypertext System for Writers and Readers of Varying Ability BIBPDF 381-387
  Michael Joyce
WALT: A Research Environment for Medical Hypertext BIBAPDF 389-394
  Mark E. Frisse; Steve B. Cousins; Scott Hassan
WALT (Washington University's Approach to Lots of Text), is a prototype interface designed to support hypertext and information retrieval research. The WALT hypertext interface can serve as a "front end" to a wide array of retrieval engines including those based on Boolean retrieval, latent semantic indexing, term frequency - inverse document frequency, and Bayesian inference techniques. The WALT interface is composed of seven distinct components: a document examination component known as the Document Browsing Area; four navigation components called the Book Shelf, the Book Spine, the Table of Contents, and the Path Clipboard; a term-based information retrieval component called Control Panel; and a relevance feedback component known as the Reader Feedback Panel. All browsing and navigation components incorporate "active text" and explicit hypertext links. WALT's most unique feature may be it's use of "book shelf" and "book spine" metaphors both to facilitate navigation and to provide a histogram-based display showing documents deemed appropriate for answering user queries.
The Virtual Notebook System BIBPDF 395-401
  Andrew M. Burger; Barry D. Meyer; Cindy P. Jung; Kevin B. Long
The ACM Hypertext Compendium: Lessons in Hypertext Publishing BIBPDF 403
  Robert M. Akscyn
InterMail: A Prototype Hypermedia Mail System BIBPDF 405-410
  Shari Jackson; Nicole Yankelovich
Applications Navigator: Using Hypertext to Support Effective Scientific Information Exchange BIBAPDF 411-416
  Ottavia Bassetti; Daniele Pagani; Marney Smyth
The Applications Navigator is an hypertext publishing solution adopted by a supercomputer manufacturer for circulating scientific information amongst its user community. Hypertext is the preferred medium for delivering complex and dynamic information because it provides a self-explanatory interface, facilitates direct searching and also encourages more general exploration, via browsing facilities. However the hypertext systems currently available do not provide proper tools for administrators of larger databases. Thus, we designed and implemented a system comprising two components: a relational back-end database and an hypertextual front-end. The back-end is designed to address the needs of database administrators: a robust and fast database management engine for data entry and update with consistency checks, flexible reporting and printing, and multiuser access. The front-end is published and distributed periodically via floppy disk to users, who need a fast, easy-to-install and easy-to-use read-only environment for browsing and searching information.

Videos

The Virtual Notebook System: An Architecture for Collaborative Work BIBPDF 417-418
  Kevin Brook Long; G. Anthony Gorry
Hypermedia Applied to Manufacturing Environments BIBPDF 419-424
  Glenna G. Gertley; Burke R. Magee
Encyclopedia of Software Components BIBPDF 425-426
  Brian Beckman; Bonnie Boyd; Joseph Jupin; Sheldon Shen; W. Van Snyder; Robert Tausworthe; L. Van Warren
SAL: A Hypermedia System BIBPDF 427-428
  Curtis Eubanks; Yasuaki Yamagishi
IKON: Developing a Prototype Static Third-Order Hypermedia System BIBA 1
  Hans C. Arents; Walter F. L. Bogaerts
This contribution presents the first results of our efforts to design and develop a static knowledge-based hypermedia system, called IKON (Intelligent Knowledge Objects Navigator). The architecture of this prototype is based on the Model-Map-View-Praxis (MMVP) architecture we have proposed for what we have called third-order hypermedia systems, or hypermedia systems which not only represent their contents' semantics, but also actively manipulate it. The implementation of IKON is based on two key ideas: the use of semi-formal or semi-structured objects for representing the information contents, network nodes and links, and the use of a frame formalism for representing the semantics of the information, the node types and the link types. The presentation of the nodes and the navigation of the links is based on the link navigation through message passing mechanism introduced in the MMVP architecture. Although only part of IKON has been implemented, some of the fundamental concepts and ideas behind the MMVP.
RelType: Relaxed Typing for Intelligent Hypermedia Representations BIBA 2
  Dilip K. Barman
Hypertext is an ideal medium to flexibly capture information, but the very flexibility precludes meaningful semantic content. RelType is a relaxed typing scheme that models hypertext as an object-oriented knowledge representation medium, by allowing but not requiring link and node type specifications with inheritable behaviors.
   RelType allows tractable retrieval from flexibly and minimally structured information that normally would be expected only from more formal representations. Traditional link following, as well as intensional query and inference based navigation, are supported information traversal modes. Knowledge posited into a potentially large hypertext can thus be intelligently retrieved and interpreted. The approach represents a novel integration of hypertext with term classification KR to usably and tractably provide semantic inference at a user-controlled level of richness.
An Architecture for Wide Area Hypertext BIBAHTML 3
  Tim Berners-Lee
Information Retrieval meets HyperText in the WorldWideWeb (W3) architecture which provides wide area information access between heterogeneous platforms, using the two user metaphors of hypertext jump and index search.
   The architecture has allowed many existing hypertext systems and information bases to be incorporated as part of the web by gateway servers. These map a portion of the W3 address space onto the address space of the system. In this way for example, Thinking Machines' "WAIS" data, Digital's "VMS/HELP" data, the Technical University of Graz's "Hyper-G" hypertext system, Internet news, and CERN's "XFIND" documentation database and telephone directory may all be browsed in a continuum with new hypertext data. W3 unites these systems and achieves a practical information universe.
   The W3 client/server architecture relies on a formal notation for the name or address of a document. The address notation is open to accommodate new protocols and name spaces as they develop within the IR and networking communities.
   Browsers use FTP, and a new search and retrieve protocol allowing negotiation between client and server about the data formats which each supports. Each browser handles as a minimum plain text, and simple SGML hypertext. SGML is used for transferring hit lists resulting from index searches, as well as being an optional documentation format. Currently in use are a graphic hypertext editor (on a NeXT machine) and a line-mode browser.
Integrating Existing Documents with Hypertext in NASA's Shuttle Mission Control Center Environment BIBA 4
  Debra S. Bettis
NASA's Space Shuttle Program like many other technical programs of its magnitude is supported by a large volume of existing technical documents. These documents are not only diverse but also abundant. Management, maintenance, and retrieval of these documents is a challenging problem by itself but; relating and cross-referencing this wealth of information when it is all on a medium of paper is an even greater challenge. Designing software to manage this information without requiring that text be re-authored is the goal of our hypertext effort.
Focused and Relativistic Hypertext Usability Assessment: Finding the Sweet Spots in Hypertext Design Space BIBA 5
  Mark H. Chignell; J. Felix Valdez; Rhona Charron
The design space for hypertext is very large and it is difficult to assess the global usability of all the points in that space. Consequently, in this paper the problem of hypertext usability assessment is considered from the perspective of formative evaluation of specific hypertext components. After reviewing some of the existing literature on hypertext usability, we recommend a featural analysis of hypertext usability based on feature dependent assessment methods. We then describe specific methodologies that have been developed for testing the usability of different approaches to link and landmark selection.
   Rather than develop global measures of usability, we favor an analysis of different components of hypertext. Thus many different usability assessment methodologies may be developed for various components of hypertext design, including the issues of link creation and landmark selection considered in this paper. To illustrate this approach, we have described three such methods. The first method for assessing link quality is obvious, and can be applied without much difficulty to most hypertext systems. The other two methods provide an interesting contrast in approaching the problem of landmark evaluation. The PI approach is a well-defined laboratory task, but it is not integrated into the hypertext browsing task. In contrast, the LESS approach integrates landmark selection into browsing so that landmarks are selected in exactly the same way (except for using a different window) as regular links are traversed. We regard the three methods presented here as illustrative of the types of feature-based hypertext usability assessment tools that should be developed as we move towards more focused analysis of hypertext usability. It is argued that the methodology for hypertext usability assessment described in this paper can be extended to cover a range of hypertext features, and that focused usability assessment is critical for development of hypertext models and environments. It is anticipated that this approach will help to identify the sweet spots in hypertext design space.
Open Multimedia Telecommunication Needs Hypertext Techniques BIBA 6
  Ralf Cordes; Hauke Peyn; Thomas Toepperwien; Thomas Weidenfeller
First attempts in modelling and structuring multimedia telecommunication services not seem to be flexible as they are required as distributed hypermedia platforms, offering personalized links, different access pathes and retrieval techniques or individualized views. In our approach (partly supported by the European Commission within the Project RACE R1038 Multimedia Communication Processing and Representation) we have combined an object oriented structuring of multimedia information according to the MHEG proposal with flexibility of the DEXTER model serving as framework for an open link server. We distinguish between object classes for particles (information nodes) like audio, video, text, pages (composite information units), links etc. The implementation has been made on SUN4 machines using SunOS4.1, Open Windows 2.0, and C++. A distributed demonstrator will be presented on TELECOM91 in Geneva in October. This prototype connects a multimedia terminal (SUN4 based), a videophone terminal and a videoserver (videodisk player) via a private broadband switch offering an extended ISDN system with a 140Mbit/s channel for highspeed data transfer in STM technique. The concept of hypertext offers the suitable features which have to be combined with the structuring of information units and service components.
Content Map Design and Knowledge Structures with Hypertext and Traditional Text BIBA 7
  Diana Dee-Lucas; Jill H. Larkin
Two experiments compared learning from three texts -- a "structured" hypertext with a content map organizing the text units, an "unstructured" hypertext with a menu-like content map, and a traditional text on a computer. Hypertext facilitated recall compared to traditional text, but the unstructured hypertext produced a more fragmented knowledge structure when readers lacked specific study goals. This suggests that minimally structured hypertexts are better for specific learning tasks than for gaining overviews of new topics. The structured hypertext was easier to use and produced more exploration, suggesting that content map design influences whether readers take advantage of hypertext's flexibility.
A Hypertext Interface to Relational Databases BIBA 8
  Martin Durr; Stefan M. Lang
In the past, database systems (DBMS) have served as a powerful tool to support a variety of tasks with a high degree of concurrent access to shared, persistent data. The large number of advantages has led to their introduction in application areas with extensive requirements -- such as cooperative environments like CASE, CAD or computer-aided instruction. Here, however, the priorities of the features are shifting towards casual user support and browsing support. In the poster, we propose an approach that adds hypertext features to existing relational databases. The main idea is to establish an interpretation component on the relational database that interprets the tuples and tables in an hypertext manner, allowing the user to work with them as if they were nodes and links. As a side effect, navigation in the hypertext fashion becomes possible on the relational data. The data itself remains unaffected. That is, it is not changed in any way by the interpretation component. Other users can access the relational data in the original way (i.e., by using SQL). Finally, the approach is generic. That is, it does not rely on any particular database, but it is applicable to any relational repository. The interlinking services are established by a rigorous analysis of the database system's data dictionary.
Extension of Hypertext to a Conceptual World: Concept Browser for a Personal Information Base BIBA 9
  Hiromichi Fujisawa; Hidefumi Kondo
An extended form of hypertext which has a "concept network" as a knowledge base is proposed. While the conventional hypertext system has association links only between units of media information, a knowledge-based hypertext system we propose here can store "concepts", "relations", and facts that are represented in terms of those concepts and relations, and links of this system also are bound between concept nodes and media information. Concepts form a taxonomical hierarchy of things which are pertinent to information to be stored in the system. Some nodes represents media information. Relations are predicates that can represent attributes of things, and facts such as "Mr. A received Prize B in 1990." A prototype, ConceptBrowser, has been developed to apply it to a "personal information base". The system supports registering new information, browsing the contents of the knowledge base, and retrieving concepts and media information. One of the attractive features is associative retrieval of concepts. We believe this kind of system can amplify information processing power of creative knowledge workers such as designers, engineers, researchers, writers, etc.
Joining Ideas BIBA 10
  Geri Gay; Deborah Trumbull; Joan Mazur
This poster reports on exploratory research that examines how students used a hypermedia program. Outcome measures include how students learned to use the system, the strategies they used to search for information, the amount of relevant information located by their searches, how information was used in their final essays, and user perceptions about the system and their use of it. Forty-one students used four search modes (Browse, Index, Guide, or a Mixture) for searches of a highly visual, interactive program. Findings suggest that designers develop a variety of interfaces to facilitate user searches, while attending to user needs, task and the environment. Crucial questions are raised about the use and interpretation of visuals for content representation and as organizers (metaphors).
Dynamically Created Guided Tours in Hypertext for Learning BIBA 11
  Catherine Guinan; Alan F. Smeaton
The aim of our work is to devise methods for searching through hypertext and presenting the nodes in a logical manner. We believe that implementing a dynamic guided tour facility which would automatically choose the best route for a user to take based on his or her search query is the next step after static guided tours and the use of information retrieval techniques to find start nodes for a user. The dynamic tour has the advantage of being directly related to the needs of the user where only relevant nodes are displayed as opposed to the static case where the author decides what is relevant before the users have even formulated their queries. As our application is to be used in a learning environment, the order of presentation in the hypertext is very important. There is no point in selecting the most relevant nodes and displaying them in random order if the user is trying to learn about the subject matter in a constructive fashion. To this end, we have introduced 'link types' to our system. There are ten distinct link types, some of which are, 'is_a', 'consists_of', 'precedes' and 'facilitates'. Using these types we rearranged the presentation order so that a logical sequence of nodes was displayed to the user. There should be a natural progression from the most basic information to the more complex so that the user does not become confused with the material.
Applying Cognitive Apprenticeship to the Design of a Hypermedia Learning Environment: The Lab Design Project BIBA 12
  Peter C. Honebein
The Lab Design Project (LDP) is a hypermedia learning environment created with Claris's HyperCard 2.0 running on Macintosh computers. The hypermedia environment is comprised of 130 megabytes of architectural blueprints, color photographs, transcribed interviews and scanned documents which create a simulated biotechnology building. This environment enables students to practice sociological research from the perspective of a sociological researcher investigating how building design influences the people who work within the building.
   The task of the students in this environment is to develop a sociological research question through the exploration of the hypermedia environment (in essence, they "walk through" the building, using a blueprint navigational system to go into labs, view work benches, look at equipment, talk with scientists in their offices, etc.), then answer that question by linking information together. For example, a student might question the existence of desk lamps in a lab. The student would search for answers to his question by reviewing documents and interviews to determine why desk lamps are in the lab. When the student finds an answer, the student links the supporting information to the picture of the lab which illustrates his question. Since the environment is collaborative, other students can access the link, comment on it, and build interpretations of the building design. The students work is continually supported and evaluated by the professor and research assistants.
   The developers of the LDP hypermedia system will be present during the poster session to discuss the pedagogical aspects of the system, namely the prescriptions of cognitive apprenticeship and their influence on hypermedia design for education.
A Measure of Hypertext Linearity BIBA 13
  Mark A. Horney
This study of 8 hypertext authors uncovered a conflict between the two common ideas: (a) that hypertext is non-linear; and (b) that hypertext readers are free to choose their own reading sequence. Trail records showed some hypertext users acting in regular, linear patterns even within large associative webs, and others working nonlinearity in sparse documents. These actions were quantified by a metric determining average ancestral path lengths for nodes as visited by particular individuals. This result suggests the concept of non-linearity must be applied separately to hypertext documents and to the hypertext reader/authors using those documents.
WITH -- A Project on Computer Supported Hypertext Construction BIB 14
  R. Kuhlen; R. Hammwohner
Hucklefine Defined BIBA 15
  Mike Mosher
...discussed in light of explorations of randomness as an organizing (or disorganizing) principle in various arts a literature.
Modeling Distributed Hyperdocuments with Markov Chains BIBA 16
  Charles Nicholas; A. Brooke Stephens; Yelena Yesha; Keith Humenik
Suppose that the nodes in a distributed hyperdocument are scattered over some file servers. Markov Chains can be used to model the performance of such hypertext systems, but calculation using existing techniques is impractical for hyperdocuments with more than about 1000 nodes. We introduce heuristics, which can be calculated in O(n) time, for estimating the relative frequency with which nodes are visited. Then, the most popular nodes can be placed at centrally-located sites, reducing communication costs. In our simulations, these heuristics are consistently within one percent of the value produced by the O(n²) Markov Chain techniques.
Using a Hypertext-Based Index to Access Hardcopy Documentation BIBA 17
  Duane Ressler
This poster illustrates how a hypertext-based index was used to provide integrated access to information in a hardcopy documentation set and to provide a structure for gradually moving portions of that documentation set online. The poster also shows the advantages that a hypertext interface can provide to the user of an online index, particularly when the index is always available as the user works with an integrated system of software products. In this way, the index becomes the support structure for a large documentation library, providing quick access to information as an online front end to hardcopy documentation.
The Hyperbase Developer's Toolkit (HDT) BIBA 18
  John Robertson; Kai Foong
The HDT has been developed to assist developers of hypersystems convert linearly structured text into a form suitable for hypermedia databases. This transformation process is classically one of the most expensive operations in hypertext system production.
   The tool provides a shell which guides the human editor through this development. First, by providing procedural direction and second, by assisting with the identification of the hypertext components within the linearly structure document.
   By providing software tools to assist the human in this editorial process, we believe that conversion costs can be reduced, thus improving hypertext systems commercial viability.
   The system also provides us with a platform to explore different conversion methods. From this work we hope to identify better procedures for producing hypertext databases from paper-based text.
Learning to Read a Hypertext: A Cognitive Approach BIBA 19
  Jean-Francois Rouet
This study examined the learning and use of a simple hypertext system by secondary school students. In the course of two training sessions, sixty subjects aged 11 to 15 were asked to answer several series of questions varying in explicitness and complexity, by searching a hypertext. We observed a significant increase in the quality of answers / search time ratio. Furthermore, subjects tended to devote a greater proportion of search time to the selection process, but only for implicit or complex questions. It is concluded that, in order to use a hypertext efficiently, inexperienced readers have to build up specific reading strategies.
Hypermedia as a Training Tool for Echocardiogaphy: An Empirical Evaluation BIBA 20
  Marc M. Sebrechts; Kathryn Permenter
The utility of hypermedia for training in echocardiography was evaluated using three learning tools. A "linear" system provided a fixed sequence of cards that controlled the presentation of videodisc-based case studies. A "structured" system provided access to the same images via an outline, organized by view and diagnostic entity. An "enhanced" version added alternative navigational strategies plus schematics, textual notes, echocardiograms and associated stethoscopic sounds. A group of fifteen cardiologists showed a strong tendency to restructure the information in a familiar linear fashion. Image recognition and diagnosis was roughly comparable across training groups, although the enhanced version did show an advantage on a test of related conceptual knowledge.
Finnegan's HyperWake -- The Clicky Way to Waking BIB 21
  Andrea Ventura
Versioning Issues in Hypermedia Publishing Environments BIBA 22
  Anja Weber
Effective support is required for the maintenance of the final and interim data that arise incrementally in cooperative publishing. Publishing can be characterized as an open-ended design-task. As a consequence, the design products, i.e. the produced hyperdocuments and especially their interim states, cannot be described sufficiently declaratively by attributes. The question arises, how the partners involved in the publishing process will find those versions of hyperdocuments, that fulfill their current information needs.
   Our approach to this problem is to maintain contextual information with the versions of hyperdocuments. We propose a hypermedia version server that differs from other approaches by
  • (1) maintaining the derivation-history of hyperdocuments consisting of nodes,
        links and composites across document boundaries,
  • (2) offering a task concept that allows coordinated, task-oriented change
        management with hyperdocuments, and
  • (3) keeping the influence of comments on the creation of new versions and the
        set up of new tasks. All this kind of recorded information can be employed to identify versions of hyperdocuments and thus improves access to versions of hyperdocuments.