August 2007
The Coming Revolution in Scholarly Communications & Cyberinfrastructure
Screencast link Compound Information Object Demo Screencast
Herbert Van de Sompel, Los Alamos National Laboratory
Carl Lagoze, Cornell University

3. Publishing Compound Objects to the Web

The layer cake metaphor is commonly used to describe information infrastructure, where new layers of functionality build upon existing layers. Tim Berners-Lee has, for example, used this model to describe the semantic web that consists of functionality built on the base web architecture.9 The work of ORE follows the same paradigm. It presumes the web architecture 10 as the de facto foundation for interoperability and positions the ORE standards as a layer over this web foundation. Thereby the ORE work leverages the facilitites provided by the web architecture, adding functionality related to compound objects that is not present in the web foundation layer.

Figure 2

Figure 2. Web Architecture (taken from http://www.w3.org/TR/webarch/).

This web foundation layer (Figure 2) defines architectural notions that allow information systems that compose compound objects to publish them to the web by associating a URI with each of the components of a compound object, thereby making the components URI-identified resources. Web services and applications, such as browsers and crawlers, can use these URIs to obtain representations of the resources via content negotiation.

Figure 3

Figure 3. Publishing a compound object to the web.

When the components of a compound object are published as resources on the web, they may link to each other (e.g., S links to 2 in Figure 3), they may link to other resources (e.g., 1 links to 8 in Figure 3), and other resources may link to them (e.g., 9 links to 2 in Figure3). These links are the basis of the rich information environment that is the web. But, because they are generally un-typed (they are standard hyperlinks), or their types do not conform to any general standard, the links do not define the boundary relationship that exists among the resources that are components of a compound object (Figure 3). The logical whole that is the compound object disintegrates into a set of distinct resources that are indistinguishable from the other resource in the web graph.

Many information systems address this problem by expressing the compound object via a user-oriented html “splash” or “jump-off” page that lists links to all components of the compound object and to a variety of related resources. This is illustrated by Figure 4, where a splash page in the arXiv provides access to the various formats in which a document is available and also to external resources, such as citations. This splash page resource is also shown in Figure 3 as resource S.

Figure 4

Figure 4. Splash page for an arXiv document (http://arxiv.org/abs/hep-th/0507171).

Pages: 1 2 3 4 5 6 7 8

Reference this article
Van de Sompel, H., Lagoze, C. "Interoperability for the Discovery, Use, and Re-Use of Units of Scholarly Communication," CTWatch Quarterly, Volume 3, Number 3, August 2007. http://www.ctwatch.org/quarterly/articles/2007/08/interoperability-for-the-discovery-use-and-re-use-of-units-of-scholarly-communication/

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