Hypertext Navigation Research Articles

A shift from chalk: multimedia and instruction

The paper discusses distance learning and multimedia tools and systems and their effects on instructional models. It considers multimedia course development aids, networks and international learning, multimedia content and hypertext navigation.

Which way now? Analysing and easing inadequacies in WWW navigation

This paper examines the usability of the hypertext navigation facilities provided by World Wide Web client applications. A notation is defined to represent the user's navigational acts and the resultant system states. The notation is used to report potential, or “theoretical” problems in the models of navigation supported by three web client applications. A usability study confirms that these problems emerge in actual use, and demonstrates that incorrect user models of the clients' facilities are common. A usability analysis identifies inadequacies in the clients' interfaces. Motivated by the analysis of usability problems, we propose extensions to the design of WWW client applications. These proposals are demonstrated by our system WEBNET which uses dynamic graphical overview diagrams to extend the navigational facilities of conventional World Wide Web client applicaions. Related work on graphical overview diagrams for web navigation is reviewed.

Understanding Hypertext Navigation through Cluster Analysis

Hypertext documents are unlike traditional text for not only do they represent a computer-based medium, but also readers can process the hypertext in a nonlinear, random access fashion. The ability to navigate through hypertext sometimes presents individuals with difficulty perhaps because these readers do not possess adequate domain knowledge or interest in the topics encountered. This study was designed to inspect the navigational profiles of participants as they process a hypertext document. Using cluster analysis, three performance profiles emerged: 1) knowledge seekers, 2) feature explorers, and, 3) apathetic hypertext users. Analyses demonstrated that domain knowledge seems to differentiate among the cluster groups. Results indicated that students who are interested in computers and hypertext but who do not possess relevant amounts of domain knowledge aligned with the text material experienced difficulty when trying to comprehend hypertext. Implications for learning, assessment, and teaching are discussed.

Using hypermedia in computer-aided instruction

The previous article in this issue (see ibid., 1996) described the Discover distributed interactive visualization system, which has been running at National Cheng-Kung University Hospital since 1993. Shortly after Discover was implemented, we observed that physicians were having trouble understanding and navigating through Discover processes for image analysis and generation. To address this problem, we developed a computer aided instruction mechanism based on hypermedia technology-multimedia with hypertext navigation. Hints (Hypermedia Information Network System) is built around the concept of hypercontrol-the use of a multimedia document to control hardware or software systems. It is currently being used with Discover at the university hospital. Physicians use this hypermedia network system to learn the processes of the discover visualization system and to help them standardize the way they examine images.

SGML: A librarian's perception

SGML, or Standard Generalised Markup Language, is an international standard (ISO 8879) allowing the logical structure of electronic documents to be represented rigorously and independent of applications. This article does not discuss the actual standard, but rather proposes a strategy libraries can consider when implementing SGML applications on top of existing products, or when embedding these in innovative end‐user services. Experiences of SGML within the VUBIS‐Antwerpen Library Network (Belgium) are discussed VUBIS‐Antwerpen has adopted SGML as a key standard for the exploitation of its bibliographical data (union catalogues, document ordering online contents, current awareness, publishing on the World Wide Web). With the move towards electronic publication and distribution of documents, SGML tends to become a crucial standard for digital libraries. Projects such as TEI, ELSA, DECOMATE and ELVYN now focus on access to and delivery of full‐text electronic documents, using SGML to manipulate, process and transform the document for the purposes of full‐text searching or hypertext navigation.

Relative Perceptibility of Hypercard Buttons Using Pictorial Symbols and Text Labels

The purpose of this experimental study was to investigate the comparative perceptibility of hypertext navigation buttons in three configurations: buttons with both pictorial symbols and text labels, with text labels only, and with pictorial symbols only. An instructional HyperCard stack was created in three versions, each differing only in the type of buttons used. Subjects were given typical situated tasks which required them to interpret navigational functions of various buttons. Findings indicated that buttons with both pictorial symbols and text labels resulted in significantly less user confusion than did buttons with pictorial symbols only. Buttons with text labels only also produced significantly less confusion, compared to those with pictorial symbols only. These findings have practical implications for hypertext designers. Many extant stacks typically use buttons with pictorial symbols only, which may create user confusion during stack navigation.

Integrated access to metabolic and genomic data.

The EcoCyc system consists of a knowledge base (KB) that describes the genes and intermediary metabolism of Escherichia coli, and a graphical user interface (GUI) for accessing that knowledge. This paper addresses two problems: How can we create a GUI that provides integrated access to metabolic and genomic data? We describe the design and implementation of visual presentations that closely mimic those found in the biology literature, and that offer hypertext navigation among related entities, and multiple views of the same entity. We employ a frame knowledge representation system (FRS) called HyperTHEO to manage the EcoCyc knowledge base. Among the advantages of FRSs are an expressive data model for capturing the complexities of biological information, and schema-evolution capabilities that facilitate the constant schema changes that biological databases tend to undergo. HyperTHEO also includes rule-based inference facilities that are the foundation of expert systems, a constraint language for maintaining data integrity, and a declarative query language. A graphic KB editor and browser allow the EcoCyc developers to interactively inspect and modify this evolving KB.

HIRMA: Hypertextual information retrieval system managed by ARIOSTO

HIRMA results in an integrated environment to query any full-text document base system by natural language sentences, obtaining a document set relevant to the query. Moreover it supports hypertextual navigation into the document base. The system uses content based document representation and retrieval methods. In this paper the representation framework as well as the retrieval and navigation algorithms used by HIRMA are described. Coverage and portability throughout application domains are supported by the lexical acquisition system ARIOSTO that provides the suitable lexical knowledge and processing methods to extract from raw text the semantic representation of documents content.

Adaptive hypertext navigation based on user goals and context

Hypertext systems allow flexible access to topics of information, but this flexibility has disadvantages. Users often become lost or overwhelmed by choices. An adaptive hypertext system can overcome these disadvantages by recommending information to users based on their specific information needs and preferences. Simple associative matrices provide an effective way of capturing these user preferences. Because the matrices are easily updated, they support the kind of dynamic learning required in an adaptive system.

Navigation in hypertext through virtual environments

Users of hypertext systems require some form of navigation aid or ‘browser’. Typically these have been produced as schematic representations of the hypertext network. The advent of ‘virtual reality’ technology, and particularly less costly forms of this, offers new possibilities for hypertext navigation whereby information can be presented in the form of a virtual environment. Users can then move around the virtual world in much the same conceptual fashion as they move around the real world. Based upon an extensive review of hypertext navigation problems and the aiding systems proposed to deal with these, four different types of navigation aid have been built; these are schematic and spatial representations in two and three dimensions. Of particular interest is the 3D spatial representation, built as a virtual environment in Virtus Walkthrough; the proposition is that such a virtual world navigation aid will offer substantial usability advantages for hypertext databases.

Using protocol analyses and drawings to study mental model construction during hypertext navigation

This study used protocol analyses and user drawings of their models of the system to investigate the “getting lost” problem in hypertext navigation. The “getting lost” problem is viewed as occurring when routine expectations of naive users, concerning appropriate linear sequences, are violated. Several ways in which users persistently attempt to work within a linear model, despite its inapplicability, are examined. The transition to more hierarchical user models is described.

Three medium-sized hypertexts on CD-ROM

A review of the Macintosh CD-ROM versions of The Manhole , the Time Table of History , and the Electronic Whole Earth Catalog with emphasis on their usability and their support of hypertext navigation. Based on the discussion of these hypertexts the following general principles are found to be useful for analyzing hypertext user interfaces: Navigational dimensions and their explicitness, directionality and literalness, landmarks, locational orientation, history lists, and backtrack mechanisms.