A hybrid system approach for supporting digital libraries

A digital library (DL) consists of a database which contains library information and a user interface which provides a visual window for users to search relevant information stored in the database. Thus, an abstract structure of a digital library can be defined as a combination of a special purpose database and a user-friendly interface. This paper addresses one of the fundamental aspects of such a combination. This is the formal data structure for linking an object oriented database with hypermedia to support digital libraries. It is important to establish a formal structure for a digital library in order to efficiently maintain different types of library information. This article discusses how to build an object oriented hybrid system to support digital libraries. In particular, we focus on the discussion of a general purpose data model for digital libraries and the design of the corresponding hypermedia interface. The significant features of this research are, first, a formalized data model to define a digital library system structure; second, a practical approach to manage the global schema of a library system; and finally, a design strategy to integrate hypermedia with databases to support a wide range of application areas. Received: 15 December 1997 / Revised: June 1999     

基于面向对象技术的多媒体开发工具YH－MMDT

ＹＨ－ＭＭＤＴ（ＭｕｌｔｉＭｅｄｉａＤｅｖｅｌｏｐｍｅｎｔＴｏｏｌｋｉｔ）是针对多媒体作品的特点，并基于面向对象技术而设计的一个多媒体开发工具包。我们提出了一个新的多媒体作品管理模型ＷＮＣＨ，该模型以作者／读者辩证统一的观点为基本观点，以结点对象为基本信息单位，以内容对象处理多媒体信息，以热区对象处理超链接功能，进而形成了一组完整的多媒体开发工具。本文首先分析了多媒体作品的特点，然后介绍了ＹＨ－ＭＭＤＴ的体系结构，并详细描述了超媒体作品管理模型ＷＮＣＨ，最后讨论了ＹＨ－ＭＭＤＴ系统的主要管理功能（如创作、阅读、导航等）和技术。     

Automatic authoring and construction of hypermedia for information retrieval

This paper describes the complete process and a tool for the automatic construction of a multimedia hypertext starting from a large collection of multimedia documents. Through the use of an authoring methodology, the document collection is automatically authored, and the result is a multimedia hypertext, also called a hypermedia, written in hypertext mark-up language (HTML), almost a standard among hypermedia mark-up languages. The resulting hypermedia can be browsed and queried with Mosaic, an interface developed in the framework of the World Wide Web Project. In particular, the set of methods and techniques used for the automatic construction of hypermedia is described in this paper, and their relevance in the context of multimedia information retrieval is highlighted.     

A scenario-based object-oriented hypermedia design methodology

This paper defines an object-oriented methodology for developing hypermedia information systems. The methodology consists of six phases: domain analysis; object modeling; view design; navigation design; implementation design; and construction. Users' requirements are analyzed with a responsibility-driven technology using scenarios. Object-oriented views are generated as the result of object modeling, and then used for the subsequent navigation and implementation design. The implementation design phase deals with database schema, page structure and flow, and user interface. This methodology integrates enterprise databases with distributed hypermedia systems via Internet, Intranet, or Electronic Commerce.     

Reading skills and children’s navigation strategies in hypertext

Prior research has identified two important navigation strategies that have a clear impact on hypertext comprehension: link selection and overview processing strategies. The first relate to the order in which students select hyperlinks while trying to comprehend a hypertext, whereas the second relate to when and for how long students process navigation overviews, a text device that conveys the text structure by displaying sections, titles and their relations. Most prior research in navigation strategies has been conducted with undergraduate students. We extend prior research by exploring the navigation strategies used by sixth-graders while reading a hypermedia system. We also investigate how reading skills relate to the use of navigation strategies, and how both shape students’ comprehension in hypertext. Results from an electronic reading study replicated in sixth-graders the results on navigation strategies previously found in undergraduate samples. In addition, the results revealed that reading skills predicted the use of link selection but not of overview processing strategies. We discuss our results in light of new models of electronic reading proficiency, and propose some instructional guidelines to improve children’ electronic reading proficiency.     

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.     

A User-Configurable Hypermedia-Based Interface Via the Functional Model of the Link

Hypermedia management systems often make use of database management systems for the persistent storage of links and of the linked information components. In this paper, we argue that a hypermedia management system with its support for reader-directed navigation provides an attractive type of database system interface in that it facilitates ease of database access or more specifically, of locating (‘discovering’) relevant information.

Furthermore, our approach to hypermedia management, based on the Functional Model of the link, provides for extensive user-configurability of that interface. This configurability particularly applies to fully dynamic links, which free the user from much of the link creation and maintenance duties.

A prototype system incorporating this approach is overviewed in this paper.     

Linking Active Anchors: A Stage in the Evolution of Hypermedia

With the advent of multimedia technology, hypertext has evolved into hypermedia, in which the elements that are linked together can include animations, video clips, music recordings, and database queries. The critical hypertext function of link traversal must undergo a parallel evolution to support the dynamic aspects of these new types of information.

This paper introduces the concept of active anchors within dynamic information and explores the design issues involved in linking to active anchors. Scenarios from our hypermedia system, Intermedia, illustrate the use of active anchors in a university setting. General conclusions recommend characteristics that may facilitate the implementation of this concept in other hypermedia systems.     

Modeling the dynamic behavior of hypermedia applications

Hypermedia applications can be defined as collections of interactive and multimedia documents that are organized as a hypertext net. The development of hypermedia applications poses specific problems, such as the need for modeling sophisticated navigational structures, interactive behaviors, and harmonic presentations involving the synchronization of contents. Moreover, the increasing popularity of Internet based systems has put stress on the lack of mechanisms to formally specify security policies when designing hypermedia applications. Traditional design models and methodologies are not suitable for hypermedia applications and the up-to-now developed hypermedia oriented models do not cover the whole set of design needs. In this context, we present Labyrinth, a hypermedia oriented model providing formal elements to describe the static structure and dynamic behavior of this kind of nonlinear, multisensory, and interactive applications     

一个超文本,面向对象和关系三者统一的数据模型

本文论述了ＥＤＢＭＳ的一个超文本、面向对象和关系三者统一的数据模型－Ｈｙｐｅｒ－ＯＲ，用以全面支持ＣＡＤ／ＣＡＭ和ＣＩＭＳ应用领域整个产品开发周期全过程的数据管理和工具集成任务。     

TIME – a multi-leveled framework for evaluating and designing digital libraries

Even though these are early days for digital libraries, three decades of research on human-computer interaction in general, and the recent history of hypermedia research in particular, indicate that whatever else occurs, the usability of digital library applications will prove crucial to widespread acceptance. In the present paper an evaluation framework (termed TIME) is outlined. TIME offers designers and implementers of digital libraries a framework to address key human factors in a user-centered manner. Bridging all levels of human factors, from the ergonomic to the user goal, TIME is a multilevel framework that highlights the interplay of multiple issues affecting user response to digital documents. Received: 15 December 1997 / Revised: June 1999     

Conceptual modeling of data-intensive Web applications

Many of the Web applications around us are data-intensive; their main purpose is to present a large amount of data to their users. Most online trading and e-commerce sites fall into this category, as do digital libraries and institutional sites describing private and public organizations. Several commercial Web development systems aid rapid creation of data-intensive applications by supporting semiautomatic data resource publishing. Automatic publishing is typically subject to the constraints of database schemas, which limit an application designer's choices. Thus, Web application development often requires adaptation through programming, and programs end up intricately mixing data, navigation, and presentation semantics. Presentation is often a facade for elements of structure, composition, and navigation. Despite this frequently unstructured development process, data-intensive applications, based on large data sets organized within a repository or database, generally follow some typical patterns and rules. We describe these patterns and rules using WebML as a conceptual tool to make such notions explicit. WebML is a conceptual Web modeling language that uses the entity-relationship (ER) model for describing data structures and an original, high-level notation for representing Web content composition and navigation in hypertext form.     

Cognitive style, hypermedia navigation and learning

This study examined the influence of cognitive style, spatial orientation and computer expertise on hypertext navigation patterns and learning outcomes when participants interacted with a hypermedia presentation. A sample of 306 undergraduates was pre-tested both on their cognitive style and on their self-reported frequency and ability in using computers. From the initial sample, 40 students were selected to form four groups with the following characteristics: (a) 10 high computer users – sequential thinkers, (b) 10 high computer users – holistic thinkers, (c) 10 low computer users – sequential thinkers and (d) 10 low computer users – holistic thinkers. All participants completed a self-report questionnaire measuring spatial orientation and were then requested to browse freely a hypermedia presentation on the ancient Mayan civilisation. Finally, the students completed a post-test to assess the recall of the hypermedia presentation and the cognitive organisation of the acquired knowledge. The results indicated that hypermedia navigation behaviour was linked to computer skills rather than to cognitive style and that learning outcomes were unaffected by cognitive style or by computer skills. However, learning outcomes were positively affected by specific search patterns, that is by re-visiting hypermedia sections and visiting overview sections in the early stages of hypermedia browsing. Further, navigating overview sections and holistic processing fostered knowledge representation in the form of maps. These findings suggest that individual differences can affect hypermedia navigation even though their role in learning is complex and the impact of cognitive style on learning outcomes was proved to be less important than initially predicted.     

Web页面两种模型对照研究

Web技术可实现Internet上跨平台超文本和超媒体的链接,使得信息查询和发布方便快捷,于是Web页面的相关技术有了深入的发展,出现了静态和动态两种页面模型。对这两种模型页面的模型及其原理、页面制作、信息（数据）传送方式、数据库的连接与访问技术等四个方面进行了对照研究。     

Effect of Web navigation style in elderly users

The population is gradually aging, but only 4% of elderly people are Internet users. These data indicate the need to take action to bridge this digital divide.Several studies show that learning and memory processes are faster when there is familiarity with the learning object, and the user finds a clear internal correspondence between the previous experience and the current experience. The elderly make up one of the groups most affected by the digital divide, with less Internet access, knowledge, and use. The Internet is by definition an almost infinite structure of hypertext, where the user navigates by using information in an active way, and where the elderly lack previous experience with hypertextual applications. The aim of this study is to test the navigation variable by comparing two designs of the same email Web application with different navigation styles: linear vs hypertextual navigation.The study consisted of usability testing, employing the method of task analysis. Other assessment tools were also used, such as the eye tracker and post-session self-report questionnaires designed ad hoc for this study.A sample of 34 users from 60 to 83 years old and with heterogeneous previous experience with new technologies participated in the study. They performed A/B testing with a counterbalanced within-subject design. The linear navigation condition, compared to the hypertextual condition, obtained a higher success rate, lower performance time, better satisfaction ratings and greater user preference.The main contribution of this study is to demonstrate the relevance of navigation in systems oriented toward the elderly, indicating that linear navigation is more suitable for these users.     

Hypermedia as an Interpretive Act

This essay will explore the epistemological foundations of hypertext and hypermedia, focusing on the need for an especially acute awareness of cognitive issues in the design and execution of academic data bases. Since hypertext as a technology has the potential to organize massive bodies of primarily academic information, we will address a number of basic interpretive and pedagogical concerns about the interpretive ‘freighting’ which such electronic intellectual archives might unintentionally produce.

At this stage of development, there is a great deal of interest and enthusiasm from the computer community in hypertext and hypermedia, but we must not ignore the ideological and hermeneutical implications of what may appear to be simple technical decisions. This essay will explore some of the implications of such ‘technical decisions’, suggesting that academicians as ‘gatekeepers’ of knowledge, must be aware of this cognitive overhead and consciously incorporate strategies in future hypertext databases which attempt to clarify their creators' critical assumptions. While hermeneutical neutrality is not possible in this cognitive universe, future hypertext and hypermedia systems must be self-consciously aware of cognitive issues.     

基于面向对象技术的数据库管理系统设计

基于面向对象技术的数据库管理系统是当今软件界研究的一个热点 ,本文结合实例就系统设计中的关键技术面向对象数据模型进行深入探讨 ,并提出了面向对象数据模型向数据库结构转换的策略     

Courseware review

David Graham is an Associate Professor of French in the Department of French and Spanish at the Memorial University of Newfoundland. His current research interests include studying picture-text links in a hypermedia database of 16th-century French emblem books and a consideration of the novels of Claude Simon as hypertext.