A posting from Bernard Vatant (Chair, OASIS Topic Maps Published Subjects TC) announces the publication of a final review working draft for Published Subjects: Introduction and Basic Requirements. The document provides an introduction to Published Subjects and specifies requirements and recommendations for publishers of PSI sets. The TC welcomes all relevant and knowledgeable comments from domain experts in information technology areas impacted by the requirements draft, viz., experts in RDF, Semantic Web, Controlled Vocabularies, and Ontologies; also Librarians, Taxonomists, and others who manage the legacy that is likely to provide the main source of Published Subjects. Published Subjects as defined in the draft Specification "provide an open, scaleable, URI-based method of identifying subjects of discourse. They cater for the needs of both humans and applications, and they provide mechanisms for ensuring confidence and trust on the part of users. Published Subjects are therefore expected to be of particular interest to publishers and users of ontologies, taxonomies, classifications, thesauri, registries, catalogues, and directories, and for applications (including agents) that capture, collate or aggregate information and knowledge." The OASIS Topic Maps Published Subjects Technical Committee has been chartered "to promote Topic Maps interoperability through the use of Published Subjects. A further goal is to promote interoperability between Topic Maps and other technologies that make explicit use of abstract representations of subjects, such as the Resource Description Framework (RDF), DAML+OIL, and the Web Ontology Language (OWL)."

Bibliographic Information

Published Subjects: Introduction and Basic Requirements. By Steve Pepper (Ontopia). OASIS Technical Committee Working Draft. Produced in the Topic Maps Published Subjects Technical Committee. Date: 9-March-2003. Document identifier: wd-pubsubj-introduction-01.

Excerpts from the Working Draft

"A subject can be an individual, like Isaac Newton, the apple that fell on his head, or a document (such as this one). It may be a class of individuals, like scientists, fruits, or OASIS specifications. It may also be a more abstract concept like gravity or inevitability. In short, a subject can be any subject of discourse that an author wishes to identify, name, represent, or otherwise make assertions about."

"Applications deal with subjects through formal representations using symbols as proxies. The term topic is used for such symbols in this document, in order to conform to Topic Maps terminology... A topic is thus the representation (inside some application) of a unique, clearly identified, and non-ambiguous subject."

"The goal of any application which aggregates information, be it a simple back-of-book index, a library classification system, a topic map or some other kind of application, is to achieve the 'collocation objective'; that is, to provide binding points from which everything that is known about a given subject can be reached. In topic maps, binding points take the form of topics; for a topic map application to fully achieve the collocation objective there must be an exact one-to-one correspondence between subjects and topics: Every topic must represent exactly one subject and every subject must be represented by exactly one topic."

"When aggregating information (for example, when merging topic maps), comparing ontologies, or matching vocabularies, it is crucially important to know when two topics represent the same subject, in order to be able to combine them into a single topic. To achieve this, the correspondence between a topic and the subject that it represents needs to be made clear. This in turn requires subjects to be identified in a non-ambiguous manner."

"The identification of subjects is not only critical to individual topic map applications and to interoperability between topic map applications; it is also critical to interoperability between topic map applications and other applications that make explicit use of abstract representations of subjects, such as RDF."

"... most subjects are not resources and thus do not have unambiguous and resolvable addresses. This is the case for all of the examples given above (with the exception of 'this document'). The identity of such 'non-addressable' subjects can only be established indirectly. Topic Maps provides a approach for doing this which may also be used in other paradigms, such as RDF. That approach is based around the notion of subject indicators."

"A subject indicator is a resource which provides some kind of compelling and unambiguous indication of the identity of a subject to humans. It may be a textual definition, description or name; it may be a visual, audio or other representation of the subject; or it may be some combination of these. A subject indicator is distinct from the subject that it indicates."

"Since subject indicators, by definition, are resources, they can always be given unambiguous addresses. Those addresses can then be used by computers as a basis for establishing identity (i.e., as unique identifiers for purposes such as automated merging) in almost the same way as computers use the addresses of addressable subjects: If two topics have the same subject indicator, then by definition they represent the same subject and should be treated accordingly. From the perspective of an application, if the identity of two topics is established by subject indicators that have the same address, they should be regarded as representing the same subject. The address of a subject indicator is called a subject identifier."