DOCSLIB.ORG

Extending an Open Hypermedia System to a Distributed Environment

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

University of Southampton Research Repository ePrints Soton Copyright © and Moral Rights for this thesis are retained by the author and/or other copyright owners. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the copyright holder/s. The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the copyright holders. When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given e.g. AUTHOR (year of submission) "Full thesis title", University of Southampton, name of the University School or Department, PhD Thesis, pagination http://eprints.soton.ac.uk University of Southampton Extending an Open Hypermedia System to a Distributed Environment by Gary John Hill A thesis submitted for the degree of Doctor of Philosophy in the Faculty of Engineering and Applied Science Department of Electronics and Computer Science May, 1994 UNIVERSITY OF SOUTHAMPTON ABSTRACT FACULTY OF ENGINEERING AND APPLIED SCIENCE DEPARTMENT OF ELECTRONICS AND COMPUTER SCIENCE Doctor of Philosophy Extending an Open Hypermedia System to a Distributed Environment by G.J. Hill The hypermedia approach to the structuring information has received a great deal of attention in recent years. Many authoring systems exist to aid in the creation of hypermedia documents, and many commercial applications utilise hypermedia techniques to implement facilities such as online help. However, these 'closed' systems are typically based upon proprietary formats and thus have limited wider applicability. This has led to the creation of so-called 'open' hypermedia systems which are able to offer an underlying, extensible hypermedia service to a wide range of applications. This thesis describes the filter-based architecture of Microcosm, an open hypermedia system developed at the University of Southampton. The functionality of the system is provided in a modular manner, allowing its facilities to be easily adapted to the requirements of the users of the system, and offering a stable platform for the investigation of novel hypermedia functionality. The extension of this model to a distributed environment is then described. The resulting system complements the flexibility of the stand-alone model with a flexible approach to the provision of distributed functionality. This allows a range of network models to be supported, from traditional client/server interaction to cooperation between users. The system is also able to support the integration of other existing distributed information services. Contents List of Figures vi List of Tables ^ Acknowledgements 1 1. Introduction 2 1.1. The Concept of Hypertext 2 1.2. Recent History of Hypertext 3 1.3. The Growth of Electronic Information Delivery 4 1.4. Overview of the Work in this Thesis 5 1.5. Declaration 7 2. The Open Approach to Hypermedia 8 2.1. Why we Need Open Hypermedia Systems 8 2.2. The First Visions 9 2.3. Defining Open Hypermedia Systems 12 2.3.1. Broadening Hypermedia Principles 12 2.3.2. Hypertext Interchange 13 2.3.3. Industrial Strength Hypermedia 14 2.3.4. Seven Issues Revisited 18 2.4. Hypermedia Standardisation 21 2.4.1. Dexter Reference Model 21 2.4.2. HyTime 22 2.4.3. MHEG Standard 23 2.5. Summary 23 3. Existing Open Hypermedia Systems 26 3.1. Introduction 26 3.2. Notecards 26 3.3. Intermedia 27 3.4. Sun's Link Service 28 3.5. Virtual Notebook System 30 3.6. HyperBase 31 3.7. PROXHY 32 3.8. Hyper-G 34 3.9. DeVise Hypermedia 36 3.10. Multicard 37 3.11. Hyperform 39 3.12. Summary 40 4. Distributed Information Systems 45 u 4.1. Introduction 45 4.2. The Dream of a Global Information Network 45 4.3. A New Generation of Distributed Information Servers 47 4.3.1. Wide Area Information Server (WAIS) 48 4.3.2. Gopher 49 4.3.3. Prospero 50 4.3.4. Other Systems 51 4.4. Hypermedia Systems with Restricted Distribution 52 4.4.1. HAM/Neptune 52 4.4.2. Knowledge Management System 53 4.4.3. Intermedia 54 4.4.4. HyperForm 54 4.4.5. Virtual Notebook System 54 4.4.6. Sun's Link Service 55 4.4.7. Summary 56 4.5. Truly Distributed Hypermedia Systems 57 4.5.1. World Wide Web 57 4.5.2. Hyper-G. 60 4.5.3. DHT 61 4.5.4. Summary 62 4.6. Conclusions 63 5. The Microcosm Framework 65 5.1. The Aims of Microcosm 65 5.2. Design History 66 5.3. Development of Microcosm 2.0 69 5.3.1. Loosely Coupled Independent Processes 69 5.3.2. Document Control System 74 5.3.3. Filter Management System 75 5.3.4. Document Viewers and Filters 75 5.3.5. Docuverse 78 5.3.6. System Configuration 79 5.4. Microcosm in Action 81 5.4.1. Open Hypermedia as an Educational Resource 82 5.4.2. Open Hypermedia as the Basis of an Integrated Environment 84 5.5. Summary 86 6. Filters and Filter Management 87 6.1. The Role of the FMS 87 m 6.2. Building a Hypermedia System with Filters 88 6.3. Simple Filter Management 92 6.3.1. Design of the FMS 92 6.3.2. Implementation and Refinement 94 6.3.3. Limitations of the Filter Chain Topology 95 6.4. Summary 104 7. Advanced Filter Management 105 7.1. Introduction 105 7.2. Active Filter Management Methods 106 7.3. Initial Implementation 108 7.3.1. Filter/FMS Interface 108 7.3.2. Message Routing 110 7.3.3. Other Aspects 113 7.4. Analysis of Performance 116 7.5. Summary 122 8. A Flexible Architecture for Distributed Hypermedia Systems 123 8.1. Introduction 123 8.2. Requirements for an Open, Distributed Hypermedia System 124 8.3. Design of the Microcosm Distributed Model 125 8.3.1. Basic Elements of the Distributed Version of Microcosm 125 8.3.2. Flexible Distribution Using Filters 126 8.3.3. Extending the Microcosm Docuverse 129 8.3.4. Providing an Open, Heterogeneous System 130 8.4. Implementation Details 131 8.4.1. Extending the Active FMS 131 8.4.2. Extending the Microcosm Docuverse 140 8.4.3. Improving Performance 142 8.4.4. Possible Improvements 143 8.5. System Testing 144 8.5.1. Performance Issues 144 8.5.2. Heterogeneous Interactions 148 8.6. Summary 149 9. Future Work 150 9.1. Development based on the Active FMS 150 9.1.1. Additional Automation of Filter Configuration 150 9.1.2. Automatic Menus 151 9.1.3. Access to Filter Configuration Details 152 IV 9.1.4. Improved Message Passing 152 9.2. Extensions to the Distributed Microcosm system 153 9.2.1. Refining the Distributed Filter Model 153 9.2.2. Computer Supported Collaborative Work 154 9.2.3. New Network Facilities 154 9.3. Future Open Hypermedia Issues 156 10. Conclusions 158 10.1. The Requirement for Open Hypermedia Systems 158 10.2. The Provision of Distributed Hypermedia Facilities 160 10.3. An Integrated Information Environment 161 A. Distributed Message Formats 163 A.l Introduction 163 A.2. Inter-FMS Messages 163 A.2.1. Locating Microcosm Servers 163 A.2.2. Obtaining Details of Published Filters 163 A.2.3. Connecting to a Remote Filter 164 A.2.4. Transferring Microcosm Messages 165 A.3. Inter-Docuverse Messages 165 Bibliography 167 V List of Figures Figure 1.1: Negroponte's Teething Rings 5 Figure 2.1: The Layers of the Dexter Hypertext Reference Model 22 Figure 3.1: Architecture of Sun's Link Service 29 Figure 3.2: The architecture of the PROXHY model 32 Figure 4.1: The growth of the Internet by network over the past 2.5 years 46 Figure 4.2: General architecture of distributed information services 47 Figure 4.3: Distributed Hypermedia Architecture proposed for Hyper-G 61 Figure 5.1: The Architecture of the Microcosm Version 1.0 Prototype 67 Figure 5.2: Microcosm 2.0 System Model 69 Figure 5.3: A Typical Microcosm Message 71 Figure 5.4: The configuration file architecture used by Microcosm 80 Figure 6.1: Filter Management System configuration dialogue box 88 Figure 6.2: The Microcosm messages understood by basic filter processes 90 Figure 6.3: The initial dual filter chain design of the simple Filter Management System 93 Figure 6.4: The inefficient routing of 'Dispatch' messages through Linkbase filters which do not understand them 97 Figure 6.5: Graph of redundant transfers of Dispatch' messages in the simple, chain-based FMS as the number of link sources increases 98 Figure 6.6: Graph of response time for the chain-based FMS with a simple filter configuration of one Linkbase and one Available Links filter 100 Figure 6.7: Graph of response time for the chain-based FMS when redundant filters are added before the Linkbase and Available Links filters 101 VI Figure 6.8; Graph of response time for the chain-based FMS when redundant filters are added between the Linkbase filter and the Available Links filter...102 Figure 6.9: Graph of response time for the chain-based FMS when multiple Linkbases all locate a certain number of links 103 Figure 7.1: Logical message flow in the passive FMS when a user requests a 'Follow Link' action 107 Figure 7.2: Logical message flow in the active FMS when a 'Follow Link' message is received 108 Figure 7.3: The new filter connection process used by the active FMS 110 Figure 7.4: Conceptual model of relationship between the data structures used by the Active FMS to store filter details 112 Figure 7.5: Configuration dialogue for the active Filter Management System 114 Figure 7.6: The improved user interface of the active Filter Management System.116 Figure 7.7: Comparison of the system response time of the active and passive Filter Management Systems 117 Figure 7.8: Constant system response time for active Filter Management System with redundant filters
Recommended publications
  • The Origins of the Underline As Visual Representation of the Hyperlink on the Web: a Case Study in Skeuomorphism

    The Origins of the Underline As Visual Representation of the Hyperlink on the Web: a Case Study in Skeuomorphism

    The Origins of the Underline as Visual Representation of the Hyperlink on the Web: A Case Study in Skeuomorphism The Harvard community has made this article openly available. Please share how this access benefits you. Your story matters Citation Romano, John J. 2016. The Origins of the Underline as Visual Representation of the Hyperlink on the Web: A Case Study in Skeuomorphism. Master's thesis, Harvard Extension School. Citable link http://nrs.harvard.edu/urn-3:HUL.InstRepos:33797379 Terms of Use This article was downloaded from Harvard University’s DASH repository, and is made available under the terms and conditions applicable to Other Posted Material, as set forth at http:// nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of- use#LAA The Origins of the Underline as Visual Representation of the Hyperlink on the Web: A Case Study in Skeuomorphism John J Romano A Thesis in the Field of Visual Arts for the Degree of Master of Liberal Arts in Extension Studies Harvard University November 2016 Abstract This thesis investigates the process by which the underline came to be used as the default signifier of hyperlinks on the World Wide Web. Created in 1990 by Tim Berners- Lee, the web quickly became the most used hypertext system in the world, and most browsers default to indicating hyperlinks with an underline. To answer the question of why the underline was chosen over competing demarcation techniques, the thesis applies the methods of history of technology and sociology of technology. Before the invention of the web, the underline–also known as the vinculum–was used in many contexts in writing systems; collecting entities together to form a whole and ascribing additional meaning to the content.
  • Hypertext Semiotics in the Commercialized Internet

    Hypertext Semiotics in the Commercialized Internet

    Hypertext Semiotics in the Commercialized Internet Moritz Neumüller Wien, Oktober 2001 DOKTORAT DER SOZIAL- UND WIRTSCHAFTSWISSENSCHAFTEN 1. Beurteiler: Univ. Prof. Dipl.-Ing. Dr. Wolfgang Panny, Institut für Informationsver- arbeitung und Informationswirtschaft der Wirtschaftsuniversität Wien, Abteilung für Angewandte Informatik. 2. Beurteiler: Univ. Prof. Dr. Herbert Hrachovec, Institut für Philosophie der Universität Wien. Betreuer: Gastprofessor Univ. Doz. Dipl.-Ing. Dr. Veith Risak Eingereicht am: Hypertext Semiotics in the Commercialized Internet Dissertation zur Erlangung des akademischen Grades eines Doktors der Sozial- und Wirtschaftswissenschaften an der Wirtschaftsuniversität Wien eingereicht bei 1. Beurteiler: Univ. Prof. Dr. Wolfgang Panny, Institut für Informationsverarbeitung und Informationswirtschaft der Wirtschaftsuniversität Wien, Abteilung für Angewandte Informatik 2. Beurteiler: Univ. Prof. Dr. Herbert Hrachovec, Institut für Philosophie der Universität Wien Betreuer: Gastprofessor Univ. Doz. Dipl.-Ing. Dr. Veith Risak Fachgebiet: Informationswirtschaft von MMag. Moritz Neumüller Wien, im Oktober 2001 Ich versichere: 1. daß ich die Dissertation selbständig verfaßt, andere als die angegebenen Quellen und Hilfsmittel nicht benutzt und mich auch sonst keiner unerlaubten Hilfe bedient habe. 2. daß ich diese Dissertation bisher weder im In- noch im Ausland (einer Beurteilerin / einem Beurteiler zur Begutachtung) in irgendeiner Form als Prüfungsarbeit vorgelegt habe. 3. daß dieses Exemplar mit der beurteilten Arbeit überein
  • Ted Nelson History of Computing

    Ted Nelson History of Computing

    History of Computing Douglas R. Dechow Daniele C. Struppa Editors Intertwingled The Work and Influence of Ted Nelson History of Computing Founding Editor Martin Campbell-Kelly, University of Warwick, Coventry, UK Series Editor Gerard Alberts, University of Amsterdam, Amsterdam, The Netherlands Advisory Board Jack Copeland, University of Canterbury, Christchurch, New Zealand Ulf Hashagen, Deutsches Museum, Munich, Germany John V. Tucker, Swansea University, Swansea, UK Jeffrey R. Yost, University of Minnesota, Minneapolis, USA The History of Computing series publishes high-quality books which address the history of computing, with an emphasis on the ‘externalist’ view of this history, more accessible to a wider audience. The series examines content and history from four main quadrants: the history of relevant technologies, the history of the core science, the history of relevant business and economic developments, and the history of computing as it pertains to social history and societal developments. Titles can span a variety of product types, including but not exclusively, themed volumes, biographies, ‘profi le’ books (with brief biographies of a number of key people), expansions of workshop proceedings, general readers, scholarly expositions, titles used as ancillary textbooks, revivals and new editions of previous worthy titles. These books will appeal, varyingly, to academics and students in computer science, history, mathematics, business and technology studies. Some titles will also directly appeal to professionals and practitioners
  • Topic Name: Www

    Topic Name: Www

    SOS POLITICAL SCIENCE AND PUBLIC ADMINISTRATION MBA FA 401 SUBJECT NAME: COMPUTER APPLICATIONS IN FINANCIAL ADMINISTRATION UNIT-V TOPIC NAME: WWW The World Wide Web (WWW), commonly known as the Web, is an information system where documents and other web resources are identified by Uniform Resource Locators (URLs, such as https://www.example.com/), which may be interlinked by hypertext, and are accessible over the Internet. The resources of the WWW are transferred via the Hypertext Transfer Protocol (HTTP) and may be accessed by users by a software application called a web browser and are published by a software application called a web server. English scientist Tim Berners-Lee invented the World Wide Web in 1989. He wrote the first web browser in 1990 while employed at CERN near Geneva, Switzerland. The browser was released outside CERN in 1991, first to other research institutions starting in January 1991 and then to the general public in August 1991. The World Wide Web has been central to the development of the Information Age and is the primary tool billions of people use to interact on the Internet. Web resources may be any type of downloaded media, but web pages are hypertext media that have been formatted in Hypertext Markup Language (HTML). Such formatting allows for embedded hyperlinks that contain URLs and permit users to navigate to other web resources. In addition to text, web pages may contain references to images, video, audio, and software components which are displayed in the user's web browser as coherent pages of multimedia content. Multiple web resources with a common theme, a common domain name, or both, make up a website.
  • The Media Assemblage: the Twentieth-Century Novel in Dialogue with Film, Television, and New Media

    The Media Assemblage: the Twentieth-Century Novel in Dialogue with Film, Television, and New Media

    THE MEDIA ASSEMBLAGE: THE TWENTIETH-CENTURY NOVEL IN DIALOGUE WITH FILM, TELEVISION, AND NEW MEDIA BY PAUL STEWART HACKMAN DISSERTATION Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in English in the Graduate College of the University of Illinois at Urbana-Champaign, 2010 Urbana, Illinois Doctoral Committee: Professor Michael Rothberg, Chair Professor Robert Markley Associate Professor Jim Hansen Associate Professor Ramona Curry ABSTRACT At several moments during the twentieth-century, novelists have been made acutely aware of the novel as a medium due to declarations of the death of the novel. Novelists, at these moments, have found it necessary to define what differentiates the novel from other media and what makes the novel a viable form of art and communication in the age of images. At the same time, writers have expanded the novel form by borrowing conventions from these newer media. I describe this process of differentiation and interaction between the novel and other media as a “media assemblage” and argue that our understanding of the development of the novel in the twentieth century is incomplete if we isolate literature from the other media forms that compete with and influence it. The concept of an assemblage describes a historical situation in which two or more autonomous fields interact and influence one another. On the one hand, an assemblage is composed of physical objects such as TV sets, film cameras, personal computers, and publishing companies, while, on the other hand, it contains enunciations about those objects such as claims about the artistic merit of television, beliefs about the typical audience of a Hollywood blockbuster, or academic discussions about canonicity.
  • Reusable Hypertext Structures for Distance and JIT Learning

    Reusable Hypertext Structures for Distance and JIT Learning

    Reusable Hypertext Structures for Distance and JIT Learning Anne Morgan Spalter Rosemary Michelle Simpson Department of Computer Science Department of Computer Science Brown University Brown University Providence, RI, USA Providence, RI, USA Tel: 1-401-863-7615 Tel: 1-401-863-7651 E-mail: [email protected] E-mail: [email protected] ABSTRACT System) developed with Ted Nelson in the 1960s[15], Software components for distance and just-in-time (JIT) FRESS (File Retrieval and Editing System), developed in the learning are an increasingly common method of encouraging 1970s and the first hypertext system used to teach a liberal reuse and facilitating the development process[56], but no arts course[21], and IRIS Intermedia in the 1980s[35][73], a analogous efforts have been made so far for designing hyper- UNIX-based networked hypertext system with advanced fea- text components that can be reused in educationalofferings. 1 tures used for teaching undergraduate and graduate courses We argue that such structures will be of tangible benefit to the online learning community, serving to offload a substan- These efforts led to the notion of an electronic book with tialburden from programmers and designers of software, as interactive illustrations, a new form of textbook that took well as allowing educators without any programming experi- advantage of the power of hypertext and the power of 2D and ence to customize available online resources. 3D interactive computer graphics. This model, however, proved difficult to apply for all but the most determined and We present our motivation for hypertext structure compo- privileged educators. Few teachers have the time, inclination, nents (HTSC) and then propose a set of pedagogicalstruc- ability, and support necessary to write a textbook or develop tures and their building blocks that reflect the categories of interactive software, using either hypertextualor linearfor- lecture, laboratory, creative project, playground, and mats (although when they do, the results can be extraordi- game[36].
  • The Nature of Hypertext: Background and Implications for Librarians

    The Nature of Hypertext: Background and Implications for Librarians

    Wilfrid Laurier University Scholars Commons @ Laurier Library Publications Library 3-1999 The Nature of Hypertext: Background and Implications for Librarians Deborah Wills Wilfrid Laurier University, [email protected] Follow this and additional works at: https://scholars.wlu.ca/lib_pub Recommended Citation Wills, Deborah, "The Nature of Hypertext: Background and Implications for Librarians" (1999). Library Publications. 8. https://scholars.wlu.ca/lib_pub/8 This Article is brought to you for free and open access by the Library at Scholars Commons @ Laurier. It has been accepted for inclusion in Library Publications by an authorized administrator of Scholars Commons @ Laurier. For more information, please contact [email protected]. THE NATURE OF HYPERTEXT: BACKGROUND AND IMPLICATIONS FOR LIBRARIANS There has been much talk in recent years about the way electronic information is breaking down the walls of the traditional library, muddying the boundary between what is owned in the library building and what can be accessed from the larger world. However, the advent of electronic hypertext is causing another kind of "breakdown," this time among individual texts. Hypertext allows connections among words or phrases in an electronic environment: highlighted text in one document links directly to other documents or to other parts of the same document. Given the flexibility of hypertext, a group of texts can form a highly complex environment with multiple paths for reading and understanding. The boundaries between individual texts, so easy to identify in the print environment, therefore lose their meaning. Hypertext is affecting the way users read, write, and think about information. Hypertext has been used in various environments, the most familiar being the World Wide Web: a space to which any individual or organization, with the appropriate computer connections, may add documents and links connecting documents.
  • Knowledge Sharing System

    Knowledge Sharing System

    Knowledge Sharing System 武田英明 Hideaki Takeda [email protected] National Institute of Informatics Hideaki Takeda / National Institute of Informatics Outline of the lecture l Scope: To learn information and knowledge sharing techniques, such as Knowledge Representation, Semantic Web and Social Network Science l Category: Artificial Intelligence, Web Informatics l Learning goal: n Conceptual understanding of recent development of the knowledge sharing technologies n Theoretical understanding of basic knowledge representation technologies n Improvement of modeling and programing skills to use the knowledge representation and sharing technologies l Prerequisite: n Some experience of programming (python, ruby, perl, etc) Hideaki Takeda / National Institute of Informatics Outline of this course l Topics: 1. Introduction 2. Information Integration 3. Semantic Web: Introduction 4. Knowledge Representation in AI: Ontology 5. Knowledge Representation in AI: Description Logics and OWL 6. Semantic Web Languages: RDF, RDFS, SPARQL 7. Semantic Web Languages: RDF, RDFS, SPARQL (cont.) 8. Semantic Web Languages: RDF, RDFS, SPARQL (cont.) 9. Linked Open Data 10. Linked Open Data (cont.) 11. Knowledge Graph 12. Knowledge Graph (cont.) 13. Practice l Style of the lecture n 2-3 talks then some small Assignments (exercise and/or presentation) n Final report Hideaki Takeda / National Institute of Informatics Outline of this course l Information sharing n What is the nature of information sharing. We can learn it from the history of Information in our society. We realize that Information sharing is inevitable. n What is the enabling technology for Information Sharing. Information Sharing consists of three layers; the information layer, the semantics layer and the social network layer.
  • CHAPTER 1 Web-Based Educational Hypermedia

    CHAPTER 1 Web-Based Educational Hypermedia

    CHAPTER 1 Web-based educational hypermedia P. De Bra Department of Computer Science, Eindhoven University of Technology, The Netherlands. Abstract The Web has revolutionized the way information is delivered to people throughout the world. It did not take long for learning material to be delivered through the Web, using electronic textbooks. The use of hypertext links gives the learner a lot of freedom to decide on the order in which to study the material. This leads to problems in understanding electronic textbooks, which can be solved using adaptive hypermedia methods and techniques. In this chapter we describe how the field of educational hypermedia benefits from user modeling and adaptation. We also show that the information gathered about the learners and their learning process can be used to improve the quality of electronic textbooks. 1 Introduction For a long time the use of hypermedia in education was limited because of the need for specialized hardware/software platforms for bringing hypermedia to the end user. Some readers may remember the Plato system [1], featuring personal and group notes, threaded discussions, hyperlinks, interactive elements and games, etc. Its use was restricted to institutes equipped with special terminals, connected to large mainframe computers running the Plato environment. A more affordable but also unsuccessful attempt at bringing hypermedia and interactivity to the pub- lic was the introduction of CD-Interactive by Philips and Sony (in 1986). Many other (hypermedia) environments suitable for delivering interactive learning mate- rial have been developed but never became popular. Then, in 1989, Tim Berners Lee started developing the ideas and software for the World Wide Web.
  • Never the Same Stream: Netomat, Xlink, and Metaphors of Web Documents Colin Post Patrick Golden Ryan Shaw

    Never the Same Stream: Netomat, Xlink, and Metaphors of Web Documents Colin Post Patrick Golden Ryan Shaw

    Never the Same Stream: netomat, XLink, and Metaphors of Web Documents Colin Post Patrick Golden Ryan Shaw University of North Carolina at University of North Carolina at University of North Carolina at Chapel Hill Chapel Hill Chapel Hill School of Information and School of Information and School of Information and Library Science Library Science Library Science [email protected] [email protected] [email protected] ABSTRACT value for designers and engineers of studying “paths not taken” during the history of the technologies we work on today. Document engineering employs practices of modeling and representation that ultimately rely on metaphors. Choices KEYWORDS among possible metaphors, however, often receive less Hypertext; XLink; browsers; XML; digital art attention than choices driven by practical requirements such as performance or usability. Contemporary debates over how to meet practical requirements always presume some shared 1 Introduction metaphors, making them hard to discern from the surrounding context in which the engineering tasks take place. One way to The metaphor of the printed page has been a prominent address this issue is by taking a historical perspective. In this and indeed from the earliest implementations of hypertext. paper, we attend to metaphorical choices by comparing two structuring principle of Web documentsd hypertext since in the contrast �irst browser, to the historical case studies of “failed” designs for hypertext on the printed page, as whatever “could not conveniently be netomat (1999), a Web browser created preAlthoughsented Nelsonor represented �irst de�ine on paper” [29, page 96], many by the artist Maciej Wisniewski, which responded to search subsequent hypertext systems treated documents as queriesWeb.
  • Getting Back on the Trail, Combating Information Overload with Topic Maps Thesis for the Cand

    Getting Back on the Trail, Combating Information Overload with Topic Maps Thesis for the Cand

    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by NORA - Norwegian Open Research Archives UNIVERSITY OF OSLO Faculty of Humanities Department of Linguistics and Scandinavian Studies (Humanistic Informatics) Getting back on the trail, combating information overload with Topic Maps Thesis for the Cand. Philol. degree Rolf B. Guescini May 8, 2006 Contents 1 Historical overview and contributions 1 1.1 Vannevar Bush . 1 1.1.1 Memex . 2 1.1.2 Sequential vs. Associative . 2 1.1.3 From Memex to hypertext . 3 1.2 Theodore Nelson . 4 1.2.1 Literary Machines . 4 1.2.2 Project XANADU . 5 1.2.3 Embedded markup . 6 1.2.4 Other visions and projects on the way . 8 1.3 Douglas Engelbart . 12 1.4 Hypertext before the World Wide Web . 14 1.4.1 Modularity, juxtaposing, and editing . 14 1.4.2 Hierarchical structure vs. non-hierarchical link structures . 15 1.4.3 Filtering of information . 16 1.4.4 Extended link functionality . 16 1.4.5 Paths . 17 1.4.6 High level info to combat overload . 18 1.4.7 Tim Berners-Lee and the World Wide Web . 18 1.4.8 Development of the World Wide Web . 19 1.4.9 WWW becomes commercial . 20 1.4.10 The World Wide Web Consortium . 21 2 The World Wide Web and HTML: What is wrong with hypertext at this point? 23 2.1 The hyper in hypertext . 24 2.1.1 Associative links . 25 2.1.2 Link directionality . 26 2.1.3 Broken links .
  • Learning from Hypertext: Research Issues and Findings

    Learning from Hypertext: Research Issues and Findings

    P1: LKK PB378-23 PB378-Jonassen-v3.cls August 26, 2003 20:53 Char Count= 0 LEARNING FROM HYPERTEXT: RESEARCH ISSUES AND FINDINGS Amy Shapiro University of Massachusetts—Dartmouth Dale Niederhauser Iowa State University information in the text. In short, there are greater metacogni- 23.1 INTRODUCTION TO THE tive demands on the reader during HAL. RESEARCH ISSUES While the vast majority of research on hypertext is not specif- ically relevant to learning, investigation into its educational util- The question of how we learn from hypertext is more com- ity began to heat up in the 1980s, and many research reports and plicated than that of how we learn from traditional text. Al- articles have been published since then. Chen and Rada (1996) though all the same elements of character decoding, word conducted a metanalytic study of learning from hypertext. Of recognition, sentence comprehension, and so forth remain the 13 studies they found comparing learning outcomes for subjects same, a number of features unique to hypertext produce added using hypertext versus nonhypertext systems, 8 revealed an ad- complexity. It is these features that drive the research of hy- vantage of hypertext. Although the combined effect size was pertext in education and have shaped our discussion in this small to medium (r = .12), it was highly significant (p< .01). chapter. In addition, they report that the effect sizes and significance lev- The most basic feature of hypertext, of course, is its nonlin- els among studies comparing learning from hypertext and linear ear structure. How nonlinear structure alters learners’ mental text were heterogeneous.