The user interface in a hypertext, multiwindow program browser

The program browsing problem is discussed, with particular emphasis on a multiple-window user interface and its implications for recording acquired knowledge, navigation, and attention-tracking. Hypertext systems are considered as an implementation of browsing techniques for nonprogram text. A classification scheme for text-viewing systems is offered, and then browsing is discussed as a nonintrusive, static technique for program study.

Multiple techniques are synthesised into a coherent plan for a multiwindow program study tool, based on theories of program browsing and the use of hypertext. A test system, HYBROW, emerged from the plan for studying the application of several hypertext multiple-window techniques to program browsing, especially window replacement. HYBROW is a hypertext, multiple-window program browser. This generic tool is applicable to any source language, although certain aspects of the preprocessing and the hierarchical browser presentation are specific to the C language. The tool permits opening an arbitrary number of text windows into an arbitrary number of files, rapid window switching, multiple-window search, placemarking, automatic screen organisation, and services for the creation, maintenance and production of study notes. An informal usability study was conducted.     

Introduction

We describe an SQL relational database schema for representing the objects in HyperCard, along with a technique for automatically populating this schema from a HyperCard stack using the facilities in HyperTalk with calls to the database manager. The standard relational database query language SQL can then be used to perform more general hypertext searches than are possible with the string search feature found in most hypertext browsing environments. Semiautomatic updates of the content of a hypertext are also possible using SQL updates on the object representations in the database to trigger corresponding HyperCard updates on the objects themselves. We describe a prototype implementation and present several example queries and updates to motivate this approach. These techniques, although demonstrated here specifically using HyperCard and Oracle for Macintosh, are generally applicable to a wide range of hypertext systems and relational databases.     

HyperFile: A data and query model for documents

Non-quantitative information such as documents and pictures pose interesting new problems in the database world. Traditional data models and query languages do not provide appropriate support for this information. Such data are typically stored in file systems, which do not provide the security, integrity, or query features of database management systems. The hypertext model has emerged as a good interface to this information; however,finding information using hypertext browsing does not scale well. We developed a query interface that serves as an extension of the browsing model of hypertext systems. These queries minimize the repeated user interactions required to locate data in a standard hypertext system. HyperFile is a prototype data server interface. In this article, we describe HyperFile, including a number of issues such as query generation, query processing, and indexing.     

Interactive information services using World-Wide Web hypertext

Most World-Wide Web information servers provide simple browsing access to collections of static text or hypertext files. This paper describes some interactive World-Wide Web servers that produce information displays and documents dynamically rather than just providing access to static files. The PARC Map Viewer uses a geographic database to create and display maps of any part of the world on demand. The Digital Tradition folk music server provides access to a large database of song lyrics and melodies. These applications take advantage of the multimedia capabilities of World-Wide Web to deliver graphical and audio content as well as formatted text. Hypertext links are used not only for navigation, but also for setting search and presentation parameters. In these applications the HTML format and the HTTP protocol are used like a user interface tool kit to provide not only document retrieval but a complete custom user interface specialized for the application.     

Effectiveness of Information Retrieval Systems Used in a Hypertext Environment

In most hypertext systems, information retrieval techniques emphasize browsing or navigational methods which, unfortunately, are not thorough enough to find all relevant material, especially when the number of nodes and/or links becomes very large. This paper reviews briefly the main query-based search techniques currently used in hypertext environments. Next, after explaining our own experimental methodology, this study concentrates on the retrieval effectiveness of these retrieval strategies. Based on our results, some discussion points are clarified and some interesting avenues for improving search effectiveness are promoted.     

Information Filtering Using User's Context on Browsing in Hypertext

Browsing is one of the most popular ways to gather information in database with hypertext structure. In order to support a user to browse, modeling of the user's interests is one of the most important issues. Although there are several promising methods to infer the interests from the user's browsing behavior, they assume that the interests are consistent during the browsing. However, the user's interests are often strongly dependent on the local context of the browsing. This paper describes a method to model the user's shifting interests from the browsing history. An information filtering method using the model of the interests has been implemented. We call it ‘context-sensitive filtering’. The results of an experimental evaluation, by real users' browsing for an encyclopedia in CD-ROM format, are also reported. This revised version was published online in July 2006 with corrections to the Cover Date.     

Information retrieval and hypertext: competing technologies or complementary access methods

Abstract. Information retrieval typically involves accessing textual information from a database in response to a user's vague information need. Hypertext or hypermedia, on the other hand, involves a user browsing through a database of textual or multimedia information in response to a variety of types of information need. Thus information retrieval can be said to have a searching metaphor while hypertext has a browsing analogy. Initially, these two technologies for information access appear to be very different, almost competitive in nature. In this paper information retrieval systems are briefly reviewed and hypertext systems are also examined. These two techniques for accessing information have been integrated into a prototype system which is described. The system dynamically generates guided tours in response to a user's query and the tour guides the user through the hypertext. Some experiments reporting on the effectiveness of this as an information access strategy are given.     

Retrieving information from hypertext: issues and problems

One of the most important developments in information science and in information systems in recent years has been the emergence of hypertext as a way of organizing information. Hypertext uses a browsing rather than a searching strategy and hypertext systems have found applications in a number of diverse areas. One of the strengths of using a hypertext system is the freedom it gives to users in the choice of information they wish to see, but this is also one of its drawbacks. This paper examines the effectiveness of hypertext as a way of retrieving information and reviews conventional information retrieval techniques which are the alternative strategy. Previous attempts at combining information retrieval and hypertext are considered and a prototype system outlined which has been developed to generate guided tours for users, to direct them through a hypertext to information they have requested. Finally, how adding this kind of intelligent guidance to a hypertext system would affect its usability as an information system is discussed.     

Using hypertext for college course information

A hypertext browsing system was compared with a linearly based command-line system for accessing information concerning college transfer courses. Usability engineering guidelines were used in ascertaining student expectations and in designing the hypertext system. A prototype was tested against a linearly based command-line system. Performance in completing two tasks was significantly faster using the hypertext system. User perceptions of the hypertext system were more favorable than those of the linearly based system. These results are discussed relative to other studies which have not found a preference for hypertext systems. Differences in the type of task used as well as the need for incorporating usability engineering guidelines are emphasized.     

Development of an HL7 interface engine, based on tree structure and streaming algorithm, for large-size messages which include image data

A basic assumption of Health Level Seven (HL7) protocol is 'No limitation of message length'. However, most existing commercial HL7 interface engines do limit message length because they use the string array method, which is run in the main memory for the HL7 message parsing process. Specifically, messages with image and multi-media data create a long string array and thus cause the computer system to raise critical and fatal problem. Consequently, HL7 messages cannot handle the image and multi-media data necessary in modern medical records. This study aims to solve this problem with the 'streaming algorithm' method. This new method for HL7 message parsing applies the character-stream object which process character by character between the main memory and hard disk device with the consequence that the processing load on main memory could be alleviated. The main functions of this new engine are generating, parsing, validating, browsing, sending, and receiving HL7 messages. Also, the engine can parse and generate XML-formatted HL7 messages. This new HL7 engine successfully exchanged HL7 messages with 10 megabyte size images and discharge summary information between two university hospitals.     

Automatic generation and refinement of hypertext links

Abstract

Current generation of hypertext systems suffer from the limitations that they are static in nature, and they do not support the automated process of link creation very well. Because of the efforts involved in manually creating links, the hyperbases created using these systems are seldom modified even when they were found not to fully support the requirements of the intended users. This paper studies the development of automated tools to aid in the process of link creation, browsing, and link refinement. Only relation links are considered in this study. The automated tools are developed to help in three of the major stages of developing and using hypertext applications: (a) during authoring to generate a set of relation links between pairs of nodes; (b) during browsing to recommend an optimal set of starting nodes for the users to begin browsing, and to guide the users at each stage of browsing by suggesting a set of “next” nodes to traverse; and, (c) during training to modify, remove and add links based on users' feedback data collected. The training will result in long-term changes in the hypertext structure.

In order to test the effectiveness of the training process objectively, a navigator is built to simulate the browsing activities of the users. The effects of training have been evaluated on two text collections using a variety of objective measures. The results indicate that the training process has improved the effectiveness of the hyperbase to support browsing.     

Age differences in the performance of hypertext perusal as a function of text topology

The present study examined the extent to which age had impacts on the performance of hypertext browsing and navigation as a function of text topology. Twenty senior adults and 20 younger adults (mean ages = 68.95 and 23.60 respectively) participated in an experiment where three levels of text linearity were manipulated. Results showed the older adult accessed fewer numbers of text nodes than the younger counterpart, which suggests that the aged appear at a disadvantage in browsing breadth. The older adult's less oriented browsing was evidenced by the larger number of nodes repeatedly visited, particularly when the network topology was perused. As for navigation, older people experienced greater disorientation given that they searched more links to locate the target node. This age difference was mainly derived from the disorientation occurring at the hybrid and network levels, with the hybrid condition resulting in the severest navigation confusion due to its mixed text structure. Implications for the design of hypertext that accommodates the age differences are discussed.     

Interactive search and browsing interface for large-scale visual repositories

Due to the rapid proliferation of both user-generated and broadcasted content, the interfaces for search and browsing of visual media have become increasingly important. This paper presents a novel intuitive interactive interface for browsing of large-scale image and video collections. It visualises underlying structure of the dataset by the size and spatial relations of displayed images. In order to achieve this, images or video key-frames are initially clustered using an unsupervised graph-based clustering algorithm. By selecting images that are hierarchically laid out on the screen, user can intuitively navigate through the collection or search for specific content. The extensive experimental results based on user evaluation of photo search, browsing and selection as well as interactive video search demonstrate good usability of the presented system and improvement when compared to the standard methods for interaction with large-scale image and video collections.     

Hypertext Access and the New Oxford English Dictionary

While hypertext access to the New Oxford English Dictionary would seem to be potentially beneficial, the conversion of such a text to a hypertext document and the generation of semantic links may not be feasible. Rather than attempting either the conversion of the text or the designation and storage of specific hypertext links, a prototype frontend called READER has been developed that provides hypertext access to the Dictionary. The emphasis in this work has been to provide the user with the browsing approach typical of hypertext rather than the more traditional query-oriented approach to accessing full-texts. The prototype is based on a dynamic hypertext model which facilitates browsing through the dynamic instantiation of implicit links existing in the text of the Dictionary.     

Age differences in the performance of hypertext perusal as a function of text topology

The present study examined the extent to which age had impacts on the performance of hypertext browsing and navigation as a function of text topology. Twenty senior adults and 20 younger adults (mean ages = 68.95 and 23.60 respectively) participated in an experiment where three levels of text linearity were manipulated. Results showed the older adult accessed fewer numbers of text nodes than the younger counterpart, which suggests that the aged appear at a disadvantage in browsing breadth. The older adult's less oriented browsing was evidenced by the larger number of nodes repeatedly visited, particularly when the network topology was perused. As for navigation, older people experienced greater disorientation given that they searched more links to locate the target node. This age difference was mainly derived from the disorientation occurring at the hybrid and network levels, with the hybrid condition resulting in the severest navigation confusion due to its mixed text structure. Implications for the design of hypertext that accommodates the age differences are discussed.     

Spatial metaphors and disorientation in hypertext browsing

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.     

超文本学习状态空间模型与学习控制

超文本教学材料的路径控制是超文本教育应用中存在的一个重要问题。文中以知识空间理论和一般的关系型超文本数学模型为基础,相入超文本学习状态空间的概念;通过定义学习状态空间的数学模型和学习状态跃迁阈值,实现对状态空间学习路径的控制,避免学生“走弯路”,提高了超文本的教学效果。在这种控制方式下,学生在学习状态内部有充分的自由浏览各个知识点;在学习状态之间学生的浏览则受到合理的控制,从而达到了自由与控制的统     

Information Foraging with a Proximity-Based Browsing Tool

This paper describes a user friendly, powerful information foraging tool. Document sets are presented through combinations of traditional ranked lists and 2-dimensional proximity-based visualisations, created by uniting graph-theoretic clustering and force-directed layout techniques, where article positions are determined by inter-document similarities. By using Gestalt principles and information encoding, the simple layout improves search efficiency by leveraging human cognitive strengths that have generally been under-utilised in commercial GUI development. In this paper, design and realisation of the layout technique are described in the context of an article browsing framework. Results of an indicative comparative laboratory study, which evaluates the client application – and in particular Graph-Theoretic Force-Directed (GTFD) visualisations against traditional search engine interfaces – are then presented. This study demonstrates the advantage of graphical presentations when browsing an article collection. Finally, potential improvements identified during the study are discussed, as are future directions for this approach to collection browsing     

A Comparative Study of Computer-Based Document Manipulation Techniques

Techniques to aid the manipulation of a computer-based document were tested by a group of 38 novice users. The subjects were given a period of time to browse the document (which employed a simple book metaphor), and were subsequently given a set of goal-related tasks in a question/answer session. The techniques tested were sequential paging, index referral, text find and embedded hypertext links. In the latter case, 3 differing types of link mechanisms were assessed and compared with each other. It was found that sequential paging and index referral were the most commonly used of the techniques. Text find was employed more for goal-related tasks than for browsing. The hypertext link technique was generally unpopular, especially for goal-related tasks. In order to establish the importance of the text find technique, the effect on reading strategies without this facility was also investigated. For browsing operations, an increase in paging and a decrease in hypertext linking was observed. In the case of goal-directed searching, an increase was observed in paging and index referral techniques.     

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.