Research on open hypermedia systems (OHSs) has been conducted since the late Eighties [Meyrowitz, 1989]. These systems employ a variety of techniques to provide hypermedia services to a diverse range of applications. The World Wide Web is the largest distributed hypermedia system in use and was developed largely independent of the research in OHSs. The popularity of the Web along with problems inherent in its design has motivated OHS researchers to integrate their systems with it. This research has primarily focused on enhancing the functionality of the Web via the services of an OHS. This paper presents three experiments exploring the integration of the Chimera OHS with the Web. While one of the experiments indeed describes work which enhances the Web, the other two investigate ways in which the Web can beneficially enhance an OHS. The paper concludes with a call for both communities to continue research which focuses on integration.

. Collaborative authoring tools generate network effects, where each tool's value depends not just on the tool itself, but on the number of other people who also have compatible tools. We hypothesize that the best way to generate network effects and to add collaborative authoring capability to existing tools is to focus on the network protocol. This paper explores a protocol-centric approach to collaborative authoring by examining the requirements and functionality of the WebDAV protocol. Key features of the protocol are nonconnection -oriented concurrency control, providing an upward migration path for existing non-collaborative applications, support for remote manipulation of the namespace of documents, and simultaneous satisfaction of a wide range of functional requirements. Introduction Despite many compelling research examples of collaborative authoring, so far their impact on actual authoring practice has been limited. While BSCW (Bentley et al., 1997) and HYPER-G (Maurer, 1996...

This paper presents an approach for providing hypermedia services in this heterogeneous setting. Central notions of the approach include the following: anchors are established with respect to interactive views of objects, rather than the objects themselves; composable, n-ary links can be established between anchors on different views of objects which may be stored in distinct object bases; viewers may be implemented in different programming languages; and, hypermedia services are provided to multiple, concurrently active, viewers. The paper describes the approach, supporting architecture, and lessons learned. Related work in the areas of supporting heterogeneity and hypermedia data modeling is discussed. The system has been employed in a variety of contexts including research, development, and education

Links are the key element for changing a text into a hypertext, and yet the WWW provides limited linking facilities. Modelled on Open Hypermedia research the Distributed Link Service provides an independent system of link services for the World-Wide Web and allows authors to create configurable navigation pathways for collections of WWW resources. This is achieved by adding links to documents as they are delivered from a WWW server, and by allowing the users to choose the sets of links that they will see according to their interests. This paper describes the development of the link service, the facilities that it adds for users of the WWW and its specific use in an Electronic Libraries project. Key words: Links, hypertext, open hypermedia, link services, authoring, HTTP proxies. 1 1. INTRODUCTION TO LINK SERVICES Hypertext environments have always provided more functionality than word-processors, and the hyper- part of the environment has been in the form of links. Links are the co...

The design of hypertext systems has been subject to intense research. Apparently, one topic was mostly neglected: how to visualize and interact with link markers.

We report about a series of experiments carried out at the University of Freiburg which demonstrate that apparantly different activities like teaching in class, telepresentation, and the production of high quality courseware can be merged into a single task. More than 20 lectures on Algorithms and Data Structures have been held using a computer whiteboard, transmitted to remote hosts over the internet, and converted into multimedia documents for offline use. We describe the developement and use of the tools required in this context, discuss the problems still to be solved, and comment on our experiences gained in experiments carried out during the last three years. We argue that Authoring on the Fly is a feasible solution to overcome the cost and labor barrier of the traditional method of courseware production.

Interoperability between existing systems, program packages, tools and applications with various degrees of hypermedia awareness is a complex and important challenge facing the hypermedia community. This paper presents a general framework (called the Flag Interoperability Matrix) to discuss and examine hypermedia system interoperability based on the concepts and principles of the Flag taxonomy of open hypermedia systems. The purposes of the Flag Interoperability Matrix are to provide a framework to classify, describe concisely and compare different approaches to hypermedia system interoperability, and provide an overview of the design space of hypermedia system interoperability. The Flag Interoperability Matrix is used to examine existing interoperability approaches. Based on a systematic analysis of possible approaches to hypermedia system interoperability, the paper explores one solution to hypermedia system interoperability that seems particularly promising with respect to handling the growing number of applications with increasing but incomplete awareness of hypermedia structure concepts.

The World Wide Web has since its beginning provided linking to and from text documents encoded in HTML. The Web has evolved and most Web browsers now support a rich set of media types either by default or by the use of specialised content handlers, known as plug-ins. The limitations of the Web linking model are well known and they also extend into the realm of the other media types currently supported by Web browsers. This paper introduces the Mimicry system that allows authors and readers to link to and from temporal media (video and audio) on the Web. The system is integrated with the Arakne Environment, an open hypermedia integration aimed at Web augmentation. The links created are stored externally, allowing for links to and from resources not owned by the (link) author. Based on the experiences a critique is raised of the limited APIs supported by plug-ins.

Abstract: As the amount of material on the World Wide Web continues to grow, users are discovering that the Web's embedded, hard-coded, links are difficult to maintain and update. Hyperlinks need a degree of abstraction in the way they are specified together with a sound underlying document structure and the property of separability from the documents they are linking. The case is made by studying the advantages of program/data separation in computer system architectures and also by re-examining some selected hypermedia systems that have already implemented separability. The prospects for introducing more abstract links into future versions of HTML and PDF, via emerging standards such as XPath, XPointer XLink and URN, are briefly discussed. Background Research on electronic hypertext systems stretches back for more than 30 years to Engelbart's [Engelbart 1968] and Nelson's [Nelson 1987a] astonishingly far-sighted work. A body of hypertext transcends normal textual documents not only by allowing user-specific annotations to be added to the corpus, but also by enabling a set of intra- and inter-document hyperlinks to weave documents together into an associative `web'. Indeed, today's World Wide Web can be regarded as a reification-- albeit flawed and full of compromises-- of what these pioneers had in mind. Over the years the idea of linking has evolved from being a purely text-related activity into the wider world of

This position paper argues that the structural computing workshop should cover more research ground than just structural computing systems. The ongoing research thread on multiple open service systems is close related to the structural computing systems research thread, and as such is very relevant to the workshop. The paper starts with a historical perspective on hypermedia infrastructure research as an attempt to place current research on structural computing systems and multiple open service systems in context. The remainder of the paper focuses on multiple open service systems. The basic ideas, goals and characteristics of multiple open service systems are described.