Session 7: (Friday am) Hypermedia Systems
21 IUHM, a hypermedia-based model for integrating open services, data and metadata Nanard Jocelyne, Nanard Marc, King Peter

Hypertext Structure, Open Hypermedia, Semantics, Metadata, Service integration

This paper discusses a new hypermedia-based model known as IUHM. IUHM emerged as a result of the development of the OPALES system, a collaborative environment for exploring and indexing video archives in a digital library. A basic design requirement of OPALES is that it must permit and support the integration of new services throughout its life cycle. Thus, IUHM depends heavily upon the notions of extensibility and openness. Support for openness, extensibility and late binding of services is provided in the IUHM model by a single reflexive mechanism. This uniform mechanism is used for describing all relationships between arbitrary system entities, including services, data and metadata. The mechanism in question consists of a generic, computable hypertext structure with typed links, known as the Information Unit, and is the minimal structural scheme to which all encapsulated entities comply. We describe and justify the design of the Information Unit, as well as the semantics of its four link types, namely role, type, owner, relative. We further describe the minimal kernel of the runtime layer responsible for the dynamic behaviour specified by the IUHM compliant hypertext network. We discuss the mechanisms involved in the dynamic binding of services and service composition. We illustrate these notions by real-world examples of the integration of metadata services within the OPALES system.

22 Structure and Behavior Awareness in Themis Kenneth M. Anderson, Susanne A. Sherba, William V. Lepthien

Open Hypermedia, structural computing, structure, behavior, awareness

The field of structural computing is working to produce techniques and tools to ease the task of developing application infrastructure--infrastructure that provides common services such as persistence, naming, distribution, navigational hypermedia, etc., over a set of application-specific or domain-specific structures. Within structural computing, "structure" refers to a combination of data and relationships over that data. Structure servers support the specification of structure and the manipulation of structures with behaviors (operations). One important aspect of structural computing is the power and flexibility it provides application developers in constructing new applications. We believe a large part of this power is due to structural computing`s ability to provide awareness services over both structure and behavior. The paper provides a definition of awareness services and describes the awareness services provided by the Themis structural computing environment. We evaluate the utility of these services by discussing how they are used within the InfiniTe information integration environment. The paper concludes with a discussion of what these services mean to the open hypermedia field (the field which gave rise to structural computing) and how they might influence the development of new hypermedia services.

23 Increasing the Usage of Open Hypermedia Systems: A Developer-Side Approach Nikos Karousos, Manolis Tzagarakis, Ippokratis Pandis

Short paper: Open Hypermedia, Hypermedia Services, Service Discovery, Web Services, Developer Support

This paper argues that the existence of a developer support framework is a critical issue to the usage of Open Hypermedia Systems (OHSs). For this reason, the OHS Community would benefit by the adoption of both a service discovery mechanism and a set of standards and tools to approach the development of hypermedia clients in a transparent and methodological manner.

24 Storm: Using P2P to make the desktop part of the Web Benja Fallenstein, Tuomas J. Lukka, Hermanni Hyytiälä, Toni Alatalo

Short paper: dangling links, peer-to-peer, location-independent identifiers, content addressable networks

We present Storm, a storage system which unifies the desktop and the public network, making Web links between desktop documents more practical. Storm assigns each document a permanent unique URI when it is created. Using peer-to-peer technology, we can locate documents even though our URIs do not include location information. Links continue to work unchanged when documents are emailed or published on the network. We have extended KDE to understand Storm URIs. Other systems such as GNU Emacs are able to use Storm through an HTTP gateway.