When we use text-based languages to exchange information, we need a default "semantic map" which is a connection (in the minds of everyone using the language) between terms in the language and the things (concepts, physical objects, ...) being discussed. In working with the RDF Model and semantic web systems, it is clear that many different techniques are being used or may be used to construct that semantic map between identifiers and their denotations.
This survey focusses specifically on the mapping of character strings functioning as identifiers, like noun phrases in English. Other approaches, such as identification-by-query, can be considered a subset of this approach, if you consider the query to be expressed in some language.
Characteristics:
Approach | Syntax | Example | Denotation | Characteristics | ||||
---|---|---|---|---|---|---|---|---|
RFC OK | Exp OK | Emb Def | Immut | Other | ||||
Overloading Web Addresses |
HTTP (etc)URI | http://.../Creator | Both a (possibly non-existant)web page and some other object, which might be documented or formally defined on the page or on a page linked from the page. | no | no | yes | no | possible semantic confusion from overloading |
Dereferencing Terms in Web Page |
HTTP (etc) URI Reference |
...22-rdf-syntax-ns#type | Some object, which might be documented or formally defined on the page or on a page linked from the page. | no | no (?) | yes | no | primary RDF approach |
Dereferencing Web Pages |
deref(HTTP URI) | *http://.../Creator | Some object which might be documented or formally defined on the page. | yes | yes | yes | no | |
Dereferencing Text Strings |
deref("some text") | englishDenotation("The person who...") | Some object which can be unambiguously described in English | yes | yes | yes | yes | may be bulky; easy to misuse through laziness |
Minting New Identifier |
uuid or tag URI | tag:w3.org/1:rdf:type | Some object | no | yes | no | n/a |
Some of these approaches can/should be sub-categorized by what is provided in triples and what is provided at the web address, but the table is already big enough.
Sandro Hawke
$Date: 2001/04/05 17:58:57 $