Effectiveness of expert semantic knowledge as a navigational aid within hypertext

Hypertext systems parse documents into content nodes connected by machine supported links or relationships. Many hypertext researchers claim that the node-link relationships of hypertext provide an information organization that models the structure of human knowledge and should therefore facilitate information access (Fiderio 1988). Yet, failures of information access occur when users lack an understanding of the overall scope and organization of a hypertext system (Gay and Mazur 1991). To support this understanding, the present research incorporated expert-based domain semantics in the design of prosthetic devices for hypertext navigation. The task domain was documentation for a word processing system. In the first experiment, the pathfinder algorithm (Schvaneveldt 1990) and cluster analysis were used to identify a set of expertbased semantic relationships between word-processing concepts. The results from these analyses contributed to the design of two prostheses to assist hypertext navigation: A hierarchical index and a local semantic browser. These aids were tested in a second experiment, crossing type of on-line documentation (semantically enhanced hypertext or an alphabetically indexed text) with level of subject expertise (novice or expert). Both performance and strategy measures suggest that the semantic prostheses improved the accessibility of information for novice users without hampering expert performance.     

Article Expertext: Intelligent hypertext

Abstract

Intelligent tutoring media can take advantage of hypertext systems and expert systems. Hypertext is text plus an abstraction of the text. In reasoning with this abstraction, a hypertext system manifests expertise. This intelligent hypertext is called expertext. When the abstraction of the text is a semantic network, spreading activation and inheritance methods may help people appreciate the structure of the hypertext. When predicates and implications are included in the abstraction, logical deductions can be performed. Queries can be logically answered and then a sequence of relevant text blocks can be provided as an explanation of the answer. Distributed expertext systems use knowledge bases about the domain of the text and about the users. Distributed expertext systems have been developed which guide people in searching for information and in creating information.     

Signposts on the digital highway: The effect of semantic and pragmatic hyperlink previews

In this article, the effect of a local, content (as opposed to structure) oriented navigation tool is investigated, i.e. mouse-over hyperlink previews. A usability experiment is described in which three groups of participants were exposed to three different versions of a website: without hyperlink previews, with content oriented, semantic previews, and with task-oriented, pragmatic previews. Participants were asked to execute search and recall tasks, and to evaluate task and hypertext. The results showed a decisive overall advantage for previews in terms of efficiency, but no effects on effectiveness or appreciation. Although semantic and pragmatic previews did not differ significantly, a post hoc analysis showed a learning effect of pragmatic previews that was absent in the semantic preview condition. It was concluded that previews fit in with the step-by-step goal orientation of hypertext users. Once users are acquainted with them, pragmatic previews speed up decision making.Apart from the experimental part, the article surveys research into the usability of navigation tools, thereby focusing on the analysis of navigation tools. The bottom line of this review is that most navigation tools as they are used in the experiments provide users with different types of information, e.g. local vs. global, content vs. structure oriented. This complicates the unequivocal explanation of their effect and may explain, together with user and task differences, the variety and inconsistencies observed in the results.     

Sleuthing in HyperHolmes : aTM an evaluation of using hypertext vs. a book to answer questions

Although hypertext offers exciting new ways of presenting and accessing information, there is little research which systematically compares the usability of hypertext against traditional media with an eye to improving the design of the hypertext. This paper presents the results of an experiment which examined the performance and navigation strategies of users engaged in a question-answering task using either a hypertext encyclopedia of Sherlock Holmes facts (the HyperHolmessy^TMstem) or the traditional paper form. The results showed that, overall, the hypertext users were marginally more accurate in answering questions, and excelled at questions where the key information was embedded in a text entry. The book users were marginally faster overall, but excelled only in answering questions based on graphics. Hypertext users showed a preference for those tools which most closely mimicked use of a conventional book. They used a hierarchical structure to guide their navigation strategy in early trials, but soon learned to navigate in a non-hierarchical, flat way.     

Using XML for Supplemental Hypertext Support

Our overall research goal is providing hypertext functionality through the WWW to hypertext-unaware information systems with minimal or no changes to the information systems. Information systems dynamically generate their contents and thus require some mapping mechanism to automatically map the generated contents to hypertext constructs (nodes, links, and link markers) instead of hypertext links being hard-coded over static contents. No systematic approach exists, however, for building mapping routines to create useful links that give users direct access to the ISs' primary functionality, give access to metainformation about IS objects, and enable annotation and ad hoc (user-declared) linking. This paper contributes a procedure for analyzing ISs and building mapping routines that supplement information systems with hypertext support. This paper also contributes an eXtensible Markup Language (XML) DTD that declares a set of elements and attributes for representing mapped information in a human-readable, machine-readable, structured, and semantic way. We implemented a prototype to demonstrate the feasibility of using XML to represent mapped information.     

The electronic business card: an experiment in half-dead hypertext

Abstract

Half-dead hypertext has links where the user has to do some work to retrieve the destination nodes (for example mount a CD-ROM or send an email message). Also, response times may be so slow that users do not have the normal hypertext feeling of freely navigating an information space. This is in contrast to normal live hypertext where the nodes appear immediately upon activation of a link anchor and dead hypertext where the links are simple cross-references to material that is not available on the computer and thus cannot be retrieved at all. Half-dead hypertext can be used in cases where live links are technically difficult or impossible to support. One example is the electronic business card, which is a link to further information about its owner. Electronic business cards can be transmitted between personal digital assistants and will allow the recipient to link to much more extensive information than can be transmitted and stored on a PDA platform. Also, electronic business card links can be printed in brochures, research papers, and other non-electronic media from which access to the server can be made with human intervention.     

Are expert users always better searchers? Interaction of expertise and semantic grouping in hypertext search tasks

The facilitative effect of expertise in hypertext information retrieval (IR) tasks has been widely reported in related literature. However, recent theories of human expertise question the robustness of this result, since previous works have not fully considered the interaction between user and system characteristics. In this study, the constraint attunement hypothesis (CAH) is considered in order to predict that the effect of expertise in IR would appear only when the user and system characteristics can be combined successfully. Results from an experiment revealed that expert users outperformed novice users in IR when the elements of a system interface are organized semantically, but not when organized randomly. Results are discussed in the framework of the CAH supporting the interactive nature of human behaviour in HCI.     

Are expert users always better searchers? Interaction of expertise and semantic grouping in hypertext search tasks

The facilitative effect of expertise in hypertext information retrieval (IR) tasks has been widely reported in related literature. However, recent theories of human expertise question the robustness of this result, since previous works have not fully considered the interaction between user and system characteristics. In this study, the constraint attunement hypothesis (CAH) is considered in order to predict that the effect of expertise in IR would appear only when the user and system characteristics can be combined successfully. Results from an experiment revealed that expert users outperformed novice users in IR when the elements of a system interface are organized semantically, but not when organized randomly. Results are discussed in the framework of the CAH supporting the interactive nature of human behaviour in HCI.     

Trams: Transportation-related air-management system

Transportation and air-quality issues are complex, coupled with the dynamic evolution of regulations, trends, and implications. The need for planners and decision makers to access current and expert information on air-quality trends, transportation planning, and applicable legislation to assist them in transportation-related air-quality management encouraged the development of the Transportation-Related Air-Management System (TRAMS). This hypertext, hypermedia system enables planners and decision makers to dynamically retrieve current information at their desktops. Transportation and air-quality information on a wide variety of related topics is organized into a branching hierarchy and presented in a consistently structured hypertext environment, allowing users to direct their own path through the resources integrated in the system design including graphics, glossary terms, crossreferences, original text materials, and expert contact information.     

An assisting,constrained 3D navigation technique for multiscale virtual 3D city models

Virtual 3D city models serve as integration platforms for complex geospatial and georeferenced information and as medium for effective communication of spatial information. In order to explore these information spaces, navigation techniques for controlling the virtual camera are required to facilitate wayfinding and movement. However, navigation is not a trivial task and many available navigation techniques do not support users effectively and efficiently with their respective skills and tasks. In this article, we present an assisting, constrained navigation technique for multiscale virtual 3D city models that is based on three basic principles: users point to navigate, users are lead by suggestions, and the exploitation of semantic, multiscale, hierarchical structurings of city models. The technique particularly supports users with low navigation and virtual camera control skills but is also valuable for experienced users. It supports exploration, search, inspection, and presentation tasks, is easy to learn and use, supports orientation, is efficient, and yields effective view properties. In particular, the technique is suitable for interactive kiosks and mobile devices with a touch display and low computing resources and for use in mobile situations where users only have restricted resources for operating the application. We demonstrate the validity of the proposed navigation technique by presenting an implementation and evaluation results. The implementation is based on service-oriented architectures, standards, and image-based representations and allows exploring massive virtual 3D city models particularly on mobile devices with limited computing resources. Results of a user study comparing the proposed navigation technique with standard techniques suggest that the proposed technique provides the targeted properties, and that it is more advantageous to novice than to expert users.     

Task-based method for creating usable hypertext

Although large hypertext documentation systems have many benefits in the commercial world, they can be difficult to build and use. To help overcome both these obstacles, a method under development at Hewlett-Packard assists authors in creating usable hypertext. A Wizard of Oz experiment was done with traditional on-line documentation and hypertext documentation to see what users liked and disliked. The experiment showed the need for a set of hypertext construction rules to ensure usability. Following these rules, and with computer assistance, authors are expected to do a task analysis of users' activities, to identify critical objects and create content nodes for them, to create links between nodes within clearly defined and cognitively justified limits, and to conduct usability tests on the resulting hypertext volume. Whilst this method recognises the importance of good clear writing, the rules and suggested prectices are not primarily about writing or screen design, but about creating a coherent navigational web that ensures success among commercial users of hypertext. The authoring system described in this paper has been developed for the HP Help system, which has been adopted as the common help delivery system for developers of Common Open Systems Environments on Unix-like platforms.     

Hierarchical search support for hypertext on-line documentation

Effectively finding relevant passages in a full-text database of software documentation calls for a user interface that does more than mimic a printed book. A hypertext approach, with a network of links among passages, offers great flexibility but often at the cost of high cognitive overhead and a disorienting lack of contextual cues. A tree-based approach guides users along branching paths through a hierarchy of text nodes. The “natural”, sequential implementation of such hierarchical access, however, is psychologically inept in large databases because it is order-dependent, discriminates awkwardly among key terms, clarifies each node's context incompletely, and often involves much semantic redundancy. An alternative, mixed approach, recently implemented in the on-line documentation system at the National Energy Research Supercomputer Center (NERSC), overcomes three of these four problems. It displays only local tree structure in response to “zoomin” or “zoomout” commands issued to focus a search begun with typical hypertext moves. This combination approach enjoys the benefits of cued, spatially interpreted hierarchical search while avoiding most of its known pitfalls. Usage monitoring at NERSC shows the ready acceptance of both zoom commands by documentation readers.     

An authorization model for a distributed hypertext system

Digital libraries support quick and efficient access to a large number of information sources that are distributed but interlinked. As the amount of information to be shared grows, the need to restrict access only to specific users or for specific usage will surely arise. The protection of information in digital libraries, however, is difficult because of the peculiarity of the hypertext paradigm which is generally used to represent information in digital libraries, together with the fact that related data in a hypertext are often distributed at different sites. We present an authorization model for distributed hypertext systems. Our model supports authorizations at different granularity levels, takes into consideration different types of data and the relationships among them, and allows administrative privileges to be delegated     

Spatial metaphors and disorientation in hypertext browsing

Abstract

The spatial metaphor can be used as a framework for explaining and designing tools that alleviate disorientation problems in hypertext systems. The approach based on this metaphor would involve developing tools analogous to navigational aids in physical environments and applying analogous concepts from research on human spatial processing and navigation in physical spaces. Research on hypertext browsing with respect to the spatial metaphor is reviewed and contrasted with the larger task context where users are trying to explore, learn, analyse, and summarize the contents of the hypertext space.     

The Micro Gallery: an evaluation of the hypertext system in The National Gallery,London

Abstract

The paper reports on a user evaluation of the Micro Gallery hypertext system of Western European Paintings at The National Gallery in London. A combination of data collection methods was used, including questionnaires before and after the use of the system and direct observation with talk aloud, to examine the impact of the interface features on searching behaviour. The diagnostic analysis highlights difficulties encountered with starting off, access points, navigation, orientation and the touch screen interaction. Linear and non-linear approaches to searching arc compared for first time and experienced users and arc discussed in terms of the completeness of user mental models.     

Metadoc: An adaptive hypertext reading system

Presentation of textual information is undergoing rapid transition. Millennia of experience writing linear documents is gradually being discarded in favor of non-linear hypertext writing. In this paper, we investigate how hypertext — in its current node-and-link form — can be augmented by an adaptive, user-model-driven tool. Currently the reader of a document has to adapt to that document — if the detail level is wrong the reader either skims the document or has to consult additional sources of information for clarification. The MetaDoc system not only has hypertext capabilities but also has knowledge about the documents it represents. This knowledge enables the document to modify its level of presentation to suit the user. MetaDoc builds and dynamically maintains a user model for each reader. The model tailors the presentation of the document to the reader. The three-dimensionality of MetaDoc allows the text presented to be changed either by the user model or through explicit user action. MetaDoc is more a documentation reading system rather than a hypertext navigation or reading tool. MetaDoc is a fully developed and debugged system that has been applied to technical documentation.     

A layered framework supporting personal information integration and application design for the semantic desktop

With the development of inexpensive storage devices, space usage is no longer a bottleneck for computer users. However, the increasingly large amount of personal information poses a critical problem to those users: traditional file organization in hierarchical directories may not be suited to the effective management of personal information because it ignores the semantic associations therein and bears no connection with the applications that users will run. To address such limitations, we present our vision of a semantic desktop, which relies on the use of ontologies to annotate and organize data and on the concept of personal information application (PIA), which is associated with a user’s task. The PIA designer is the tool that is provided for building a variety of PIAs consisting of views (e.g., text, list, table, graph), which are spatially arranged and display interrelated fragments of the overall personal information. The semantic organization of the data follows a layered architecture that models separately the personal information, the domain data, and the application data. The network of concepts that ensues from extensive annotation and explicit associations lends itself well to rich browsing capabilities and to the formulation of expressive database-like queries. These queries are also the basis for the interaction among views of the PIAs in the same desktop or in networked desktops. In the latter case, the concept of desktop service provides for a semantic platform for the integration of information across different desktops and the web. In this paper, we present in detail the semantic organization of the information, the overall system architecture and implementation aspects, queries and their processing, PIAs and the PIA designer, including usability studies on the designer, and the concepts of semantic navigation in a desktop and of interoperation in a network of desktops. This work was partially supported by NSF Awards ITR IIS-0326284 and IIS-0513553. A preliminary version of this paper was presented at the First International Workshop on the Semantic Desktop—Next Generation Personal Information Management and Collaboration Infrastructure, Galway, Ireland, November 2005 (in association with the International Semantic Web Conference): “A Multi-Ontology Approach for Personal Information Management,” by Huiyong Xiao and Isabel F. Cruz.     

Interface Alternatives for Hypertexts

This paper seeks to make explicit the ranges of design choices among which authors select whenever they create a particular hypertext. These choices are grouped into five categories: the links authors provide which influence the routes that readers can take within the text; the design features relating to the initiation of jumps within the hypertext; the visual characteristics of the destination of a jump; the navigation support that can be offered to readers; the design implications of the tasks that people will be trying to accomplish using the hypertext. It is suggested that the interface characteristics which are most helpful for hypertexts written as tutorials may differ from those design features which benefit users wishing to gain access through hypertexts to large (encyclopaedic) information sources, or hypertexts used by people as a means of personal information management. Although there is little evidence about which design features work best in which circumstances, an understanding of the range of interface options may help authors appreciate the tradeoffs they often have to make when designing hypertexts.     

Semantic similarity measures for enhancing information retrieval in folksonomies

Collaborative tagging systems, also known as folksonomies, enable a user to annotate various web resources with a free set of tags for sharing and searching purposes. Tags in a folksonomy reflect users’ collaborative cognition about information. Tags play an important role in a folksonomy as a means of indexing information to facilitate search and navigation of resources. However, the semantics of the tags, and therefore the semantics of the resources, are neither known nor explicitly stated. It is therefore difficult for users to find related resources due to the absence of a consistent semantic meaning among tags. The shortage of relevant tags increases data sparseness and decreases the rate of information extraction with respect to user queries. Defining semantic relationships between tags, resources, and users is an important research issue for the retrieval of related information from folksonomies. In this research, a method for finding semantic relationships among tags is proposed. The present study considers not only the pairwise relationships between tags, resources, and users, but also the relationships among all three. Experimental results using real datasets from Flickr and Del.icio.us show that the method proposed here is more effective than previous methods such as LCH, JCN, and LIN in finding semantic relationships among tags in a folksonomy.