September 2, 2002

Objects & ontologies & metadata thoughts.

Should eLF develop an ontology of learning?

To share common understanding of the structure of information among people or software agents

To enable reuse of domain knowledge

To make domain assumptions explicit

To separate domain knowledge from the operational knowledge

To analyze domain knowledge

Abstract: Ontology Development 101: A Guide to Creating Your First Ontology

Some classes, instances, and relations among them in the wine domain. We used black for classes and red for instances. Direct links represent slots and internal links such as instance-of and subclass-of.

One can reuse existing ontologies: There are libraries of reusable ontologies on the Web and in the literature. For example, we can use the Ontolingua ontology library (http://www.ksl.stanford.edu/software/ontolingua/) or the DAML ontology library (http://www.daml.org/ontologies/). There are also a number of publicly available commercial ontologies (e.g., UNSPSC (www.unspsc.org), RosettaNet (www.rosettanet.org), DMOZ (www.dmoz.org)).

A Gazillion references from the Digital Library crowd

An Idiot’s Guide to the Resource Description Framework

The Resource Description Framework (RDF) – developed by the World-Wide Web Consortium (W3C) – provides the foundation for metadata interoperability across different resource description communities. One of the major obstacles facing the resource description community is the multiplicity of incompatible standards for metadata syntax and schema definition languages. This has lead to the lack of, and low deployment of, cross-discipline applications and services for the resource description communities. RDF provides a solution to these problems via a Syntax specification (W3C, 1999a) and Schema specification (W3C, 1998a).

RDF is based on Web technologies and, as a result, is lightweight and highly deployable. RDF provides interoperability between applications that exchange metadata and is targeted for many application areas including; resource description, site-maps, content rating, electronic commerce, collaborative services, and privacy preferences. RDF is the result of members of these communities reaching consensus on their syntactical needs and deployment efforts.

The objective of RDF is to support the interoperability of metadata. RDF allows descriptions of Web resources – any object with a Uniform Resource Identifier (URI) as its address – to be made available in machine understandable form. This enables the semantics of objects to be expressible and exploitable. Once highly deployed, this will enable services to develop processing rules for automated decision-making about Web resources.

RDF is based on a concrete formal model utilising directed graphs that elude to the semantics of resource description. The basic concept is that a Resource is described through a collection of Properties called an RDF Description. Each of these Properties has a Property Type and Value. Any resource can be described with RDF as long as the resource is identifiable with a URI as shown in Figure 1.

An RDF “graph”


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