Open Hypermedia Research Articles

Interview with Niels Olof Bouvin

Niels Olof Bouvin is 45 years old, and is an associate professor at the Department of Computer Science, Aarhus University, Denmark. His 2001 PhD dissertation was on the topic of augmenting the web with open hypermedia. He was a co-winner of the Douglas Engelbart Best Paper Award in 1997 and 2006.

The World Wide Web, Hyper-G and Microcosm: Historical Analysis and Future Integration Directions

ABSTRACT Hypertext systems went through several stages of development and dedicated research efforts. Currently, the World Wide Web is the backbone which links massive amount of hypertext and hypermedia documents published by communities and individuals working from all parts of the universe. However, the history of hypertext systems reveals that there were a competition between the Web and two open hypermedia systems which are Hyper-G and Microcosm. The aim of this paper is to investigate the success factors of the Web and present the ways of including open hypermedia features in the Web. General Terms Web Technology, Information Systems. Keywords Microcosm, Hyper-G, Open Hypermedia, the World Wide Web. 1. INTRODUCTION Hyper-G, Microcosm and the World Wide Web were developed in parallel since 1989 [1, 2 and 3]. The development of the Web is accredited to Tim Berners Lee and other researchers who were working at CERN laboratory, Switzerland [1 and 4]. Moreover, Hyper-G was implemented at the Graz University of Technology in Austria while Microcosm’s development was at the University of Southampton in the United Kingdom [3 and 5]. Hyper-G and Microcosm were retrieving links from link bases rather than embedding them inside documents. Moreover, Microcosm differs from Hyper-G and the Web in that it was originally designed as a peer-to-peer system while the latter two were following the client/server architecture [4]. Therefore, knowing the motives behind the Web’s tremendous victory is essential. In this paper, the reasons are discussed from many perspectives in Section 1 and Section 2. The following section investigates the ways of exploiting open hypermedia features in improving the Web.

An Inquiry-led Personalised Navigation System (IPNS) using multi-dimensional linkbases

The simplicity of the hypertext model behind the World Wide Web is a factor in its success, but this simplicity brings limitations. One of these limitations is embedding links in documents. Open Hypermedia addresses this by instead storing them in separate link databases. Meanwhile, the Adaptive Hypermedia approach seeks to enhance a user's experience by inserting personalised additional content and links on the web page. However, these techniques do not offer the user any control over the adaptation. In this paper, we propose the concept of a multi-dimensional linkbase for adaptive links presentation. Links are created and stored in a single, multi-dimensional, linkbase that provides presentation links based on the user's preferences and profile. We present a web-based system Inquiry-led Personalised Navigation System that implements this multi-dimensional concept for controlling its personalisation of hyperlinks. We give the results of our evaluation, which confirm that user-controlled adaptation is a satisfactory approach to providing users with control over personalisation, and can alleviate the link overload problem.

A schema-based P2P network to enable publish-subscribe for multimedia content in open hypermedia systems

Open Hypermedia Systems (OHS) aim to provide efficient dissemination, adaptation and integration of hyperlinked multimedia resources. Content available in Peer-to-Peer (P2P) networks could add significant value to OHS provided that challenges for efficient discovery and prompt delivery of rich and up-to-date content are successfully addressed. This paper proposes an architecture that enables the operation of OHS over a P2P overlay network of OHS servers based on semantic annotation of (a) peer OHS servers and of (b) multimedia resources that can be obtained through the link services of the OHS. The architecture provides efficient resource discovery. Semantic query-based subscriptions over this P2P network can enable access to up-to-date content, while caching at certain peers enables prompt delivery of multimedia content. Advanced query resolution techniques are employed to match different parts of subscription queries (subqueries). These subscriptions can be shared among different interested peers, thus increasing the efficiency of multimedia content dissemination.

Interview with Uffe K. Wiil

Uffe Kock Wiil is a professor at the Maersk Mc-Kinney Moller Institute, University of Southern Denmark. He holds a M.Sc. in Computer Engineering (1990) and a Ph.D. in Computer Science (1993) from Aalborg University, Denmark. He has previously held positions at Aalborg University and University of Aarhus (both in Denmark). He also spent time visiting Texas A&M University (1991--92) and University of California, Irvine (1996). He has held various academic management positions from 1998--2006 including Department Head and Dean. He has served the hypertext community in many ways including Chair of the Open Hypermedia Systems Working Group (OHSWG) (1997--2001), Program Chair (ACM Hypertext 1999), General Chair (ACM Hypertext 2006), and ACM SIGWEB Treasurer (1997--1999, 2003--2005).

Adaptive hypermedia through contextualized open hypermedia structures

The aim of this article is to produce an alternative view of the adaptive hypermedia (AH) domain from a contextually-aware open hypermedia (OH) perspective. We believe that a wide range of AH techniques can be supported with a small number of OH structures, which can be combined together to create more complex effects, possibly simplifying the development of new AH systems. In this work we reexamine Brusilovsky's taxonomy of AH techniques from a structural OH perspective. We also show that it is possible to identify and model common structures across the taxonomy of adaptive techniques. An agent-based adaptive hypermedia system called HA 3 L is presented, which uses these OH structures to provide a straightforward implementation of a variety of adaptive hypermedia techniques. This enables us to reflect on the structural equivalence of many of the techniques, demonstrates the advantages of the OH approach, and can inform the design of future adaptive hypermedia systems.

Magpie: Experiences in supporting Semantic Web browsing

Magpie has been one of the first truly effective approaches to bringing semantics into the web browsing experience. The key innovation brought by Magpie was the replacement of a manual annotation process by an automatically associated ontology-based semantic layer over web resources, which ensured added value at no cost for the user. Magpie also differs from older open hypermedia systems: its associations between entities in a web page and semantic concepts from an ontology enable link typing and subsequent interpretation of the resource. The semantic layer in Magpie also facilitates locating semantic services and making them available to the user, so that they can be manually activated by a user or opportunistically triggered when appropriate patterns are encountered during browsing. In this paper we track the evolution of Magpie as a technology for developing open and flexible Semantic Web applications. Magpie emerged from our research into user-accessible Semantic Web, and we use this viewpoint to assess the role of tools like Magpie in making semantic content useful for ordinary users. We see such tools as crucial in bootstrapping the Semantic Web through the automation of the knowledge generation process.

Are Laws of Ranganathan Valid in Virtual Libraries?

Defines an empirical law as discovered, defined and formulated by scientists and states their kinds. Explains how S R Ranganathan sensed a lack of normative laws to guide library services and methods and subsequently formulated by Five Laws of library Science in 1920s. Examines the question whether the laws, which worked well in the print on paper paradigm, are still valid in electronic information. Characteristics of virtual libraries and that of ultra modern documents facilitated by the IT are examined. Enumerates the implication of the Laws with respect to the ubiquitous Internet, Electronic publishing, Information Literacy, Virtual Reference Desks, Open Access Archives, Information Transfer, Knowledge Management, Information Marketing, OPACs and Hypermedia. Finds that all the new concepts and processes facilitate the implications of the Laws which square well with the IT enabled services and information society.

Magpie: Experiences in Supporting Semantic Web Browsing

Magpie has been one of the first truly effective approaches to bringing semantics into the web browsing experience. The key innovation brought by Magpie was the replacement of a manual annotation process by an automatically associated ontology-based semantic layer over web resources, which ensured added value at no cost for the user. Magpie also differs from older open hypermedia systems: its associations between entities in a web page and semantic concepts from an ontology enable link typing and subsequent interpretation of the resource. The semantic layer in Magpie also facilitates locating semantic services and making them available to the user, so that they can be manually activated by a user or opportunistically triggered when appropriate patterns are encountered during browsing. In this paper we track the evolution of Magpie as a technology for developing open and flexible Semantic Web applications. Magpie emerged from our research into user-accessible Semantic Web, and we use this viewpoint to assess the role of tools like Magpie in making semantic content useful for ordinary users. We see such tools as crucial in bootstrapping the Semantic Web through the automation of the knowledge generation process.

Extending types to modelling problem-space entities

Structural computing has evolved from work on open hypermedia to aid in the construction of domain-specific software infrastructure and tools. Part of the premise of structural computing has been that by focusing on the abstraction of structure rather than on a concrete data layer, it should make it easier for developers to use appropriate levels of abstraction to build applications. By using the appropriate level of abstraction, the resulting systems can represent components in ways that closely reflect the problem space, instead of forcing the problem into an implementation-centric paradigm. Our previous work has concentrated on how to accomplish these ends through the abstraction of data—this paper concentrates on the benefits of abstraction of type. As our concern is primarily with modelling the problem space in an application domain, we approach ‘type’ initially from a problem-space viewpoint, not from a theoretic model. ‘Type’ is not a monolithic concept: a type may be an interface definition, a set of properties, or a classification. The meaning of a type depends on the individual entity to which the type is being applied, as well as the context in which the typing occurs. The meaning of ‘type’ in a problem domain may differ greatly from ‘type’ in an application addressing that domain, and the distinction must be kept clear. Types, like the entities to which they are applied, are not necessarily static. This observation is especially important in applications addressing domains that involve complex activities. This paper proposes a framework for distinguishing among the varieties of ‘type’ and describes uses for each. In the context of structural programming, we discuss techniques for building context-dependent extensions to existing types (whether interface definitions or classifications) that support applications where both the definitions of types and the classification of items are subject to change. We contextualize this work with respect to related research, and with more general software development concerns.

Patterns of message interchange in decoupled hypermedia systems

Open hypermedia systems provide a decoupled approach to structural computing. This entails that the architecture of the systems are made up of user agents that communicate with distributed link servers. This in turn raises the consideration of the different message exchange patterns that may be implemented in such interaction, which determines the behaviour of systems according to them. The definition of such exchange patterns is critical if interoperability and flexibility are design objectives. This paper describes a structural model for such kind of message patterns, and provides a list of possible courses of interaction. Then, the influence of such heterogeneity of communication patterns is analyzed from the perspective of composing structure in hypermedia, and a framework for their integration is sketched. This represents a first attempt to advance current Service-Oriented specifications for decoupled hypermedia to cover the heterogeneity of potentially diverging system behaviours.

GOHSE: Ontology Driven Linking of Biology Resources

We describe the GOHSE system, an application to support browsing of biology resources. The Conceptual Open Hypermedia Service (COHSE) system enhances web resources through the dynamic addition of hypertext links. These links are derived through the use of an ontology and associated lexicon along with a mapping from concepts to possible link targets. GOHSE applies COHSE to Bioinformatics, using the Gene Ontology (GO) as an ontology and associated keyword mappings and GO associations as link targets. The resulting demonstrator provides both glossary functionality and the possibility of building knowledge based hypertext structures linking bioinformatics resources.

GOHSE: Ontology driven linking of biology resources

We describe the GOHSE system, an application to support browsing of biology resources. The Conceptual Open Hypermedia Service (COHSE) system enhances web resources through the dynamic addition of hypertext links. These links are derived through the use of an ontology and associated lexicon along with a mapping from concepts to possible link targets. GOHSE applies COHSE to Bioinformatics, using the Gene Ontology (GO) as an ontology and associated keyword mappings and GO associations as link targets. The resulting demonstrator provides both glossary functionality and the possibility of building knowledge based hypertext structures linking bioinformatics resources.

Meme media architectures for re-editing and redistributing intellectual assets over the Web

While current Web technologies have allowed us to publish intellectual assets in world-wide repositories, and to browse the resulting massive accumulation, we have no effective tools yet to flexibly re-edit and redistribute such intellectual assets for their reuse in different contexts. Open Hypermedia Systems addressed the problem of augmenting third-party applications in 90 s, and more recently Web augmentation. We need extended OHS technologies for the advanced reuse of Web-published intellectual assets through re-editing and redistributing them. Meme media and meme pool technologies will work as such extended Open Hypermedia Systems technologies to annotate, re-edit, and redistribute Web-published assets. This paper reviews the IntelligentPad and IntelligentBox meme media architectures together with their potential applications, and proposes both the use of XML/XSL or XHTML to define two-dimensional meme media objects. When applied to Web contents, meme media technologies make the World Wide Web operate as a meme pool, where people can publish their intellectual assets as Web pages, access some Web pages to extract some of their parts as meme media objects through drag-and-drop operations, visually combine these meme media objects together with other meme media objects to compose new intellectual assets, and publish these assets again as Web pages. Our framework creates a new vista in the circulation and reuse of our knowledge represented as multimedia documents and/or application programs, especially in the field of science.

Exploiting link types during the conceptual design of websites

With recent developments in World Wide Web technology, expressiveness of websites and web applications is starting to converge to the functionality offered by Open Hypermedia Systems. In this paper, we examine how link typing, and an appropriate link definition can be used during the website design process. Different existing approaches to link categorisation are reviewed before going into closer detail to the concept of link and its properties. Next, four different types of links are defined, with a description of how each of them can be exploited to enhance the design process as well as the usability of the website. Explicitly modelling the links as belonging to one of these four categories during the design phase allows separaration of concerns during the modelling process; provides for clearer design guidelines; allows for better usability, multiple customised presentations, and other automatically generated enhancements to websites (e.g. site map, in-page navigation structures, etc). The approach is presented in the context of WSDM, an audience driven website design method, but the principles are generally applicable.

Structuring primitives in the Callimachus component-based open hypermedia system

Driven by the philosophy of the ‘primacy of structure over data’, Component-Based Open Hypermedia Systems (CB-OHS) present an open set of structure servers providing structural abstractions of different hypermedia domains. To address the emergent requirements and to facilitate the development of structure servers, structure should be handled as a first class entity. We propose patterns for structure, called templates, that define the structural model upon which structure servers operate. We present how structure servers are developed and operate in the Callimachus CB-OHS. Development of structure servers within Callimachus is based on the explicit specification of structure with the use of an atomic structural primitive called the structural element. Explicit structure specification eases the development of structure servers in CB-OHS, making such development less error prone and providing the basis for tailoring domain specific abstractions.

Visualizing and interacting with hypermedia-based process-centric enterprise models

Interoperability and cross-fertilization of multiple hypermedia domains are relatively new concerns to the open hypermedia and structural computing community. Recent work in this area has explored integrated data models and component-based structural service architectures. This paper focuses on the user interface aspects relating to client applications of the structural services. It presents an integrative design of a graphical hypermedia user interface for hypermedia-based process-centric enterprise models. An enterprise model covers various important perspectives of an enterprise (such as processes, information, organization, and systems). In this paper, examples are given to show that these perspectives are presented better using a mixture of hypermedia structures found in several hypermedia domains. The visualization and interaction design for such hypermedia-based enterprise models integrates many features found in navigational, spatial, taxonomic, workflow and cooperative hypertext domains. A use case is provided to show that client applications based on this design allow users to see and interact with an enterprise model from multiple perspectives. In addition, some` initial user experience is also reported.

Discussions at the data border: from generalised hypertext to structural computing

Structural Computing grew from the trend in hypertext research towards generalised systems, it asserts the primacy of structure over data. As a philosophy it has been compared to Structuralism in anthropology and linguistics and has given birth to a new trend in systems design known as Multiple Open Services (MOS). The Fundamental Open Hypermedia Model (FOHM) is an alternative approach to Generalised Hypertext that views the various Hypertext domains as continuous rather than discrete. Its relationships to Structural Computing, Structuralism and MOS have never been fully explored. This paper examines these relationships. We explore how FOHM might be implemented in MOS environments and describe the Data Border, the point where Structure meets Data. We then use this to explore how FOHM and Generalised Hypermedia are related to Structuralism and Structural Computing.

The TrailTRECer Framework: Applying Open Hypermedia Concepts to Trails

The TrailTRECer Framework: Applying Open Hypermedia Concepts to Trails

Open hypermedia for product support

As industrial systems become increasingly more complex, the maintenance and operating information increases both in volume and complexity. With the current pressures on manufacturing, the management of information resources has become a critical issue. In particular, ensuring that personnel can access current information quickly and effectively when undertaking a specific task. This paper discusses some of the issues involved in, and the benefits of using, open hypermedia to manage and deliver a diverse range of information. While the paper concentrates on the problems specifically associated with manufacturing organizations, the problems are generic across other business sectors, such as healthcare, defence and finance. The open hypermedia approach to information management and delivery allows a multimedia resource base to be used for a range of applications and it permits a user to have controlled access to the required information in an easily accessible and structured manner. Recent advancement in hypermedia also permits just-in-time support in the most appropriate format for all users. Our approach is illustrated by the discussion of a case study in which an open hypermedia system delivers maintenance and process information to factory-floor users to support the maintenance and operation of a very large manufacturing cell.