Domain Name(Space) Identifiers (DNIDs) take advantage of the inherent uniqueness of domain names to allow publishers and users to establish and infer unique identifiers for digital objects available on the Internet. They are intended as a lightweight supplement to existing schemes for unique identification such as Handles, Digital Object Identifiers, and the Crossref System. Currently, DNIDs work best when referring to discrete entities, such as objects in a museum collection, which already have unique identifiers that can be discovered through web-based tools.
"numismatics.org:1858.1.1" is a DNID that uniquely refers to a coin in the collection of the American Numismatic Society (ANS). In this instance “numismatics.org” is the domain name of that institution and “1858.1.1” is the accession number of the first coin donated to the ANS collection. It is likely that when it occurs in a web-page this DNID string is an unambiguous reference to that ANS coin. A Google search on numismatics.org:1858.1.1 shows links to pages that refer to this coin, indicating that the DNID is an actionable identity leading to discovery of relevant information about this object.
This example illustrates another feature of DNID's. They require no new user software to be useful. In fact, the scheme is intended to leverage the ability of Google and other search engines to find particular character sequences on publicly available web pages.
A DNID can be formed from one of the following:
The above is an informal description of the possible forms of DNIDs. A formal declaration is under development.
Examples are:
The first two make use of the unambiguous combination of a domain name and a locally unique identifier. The third takes a valid url - http://classics.uc.edu/troy - and derives a DNID by appending a locally unique id to its host and path components. The fourth uses a valid domain name, an inferred but not official path component, and the accession number of an object to derive a DNID.
DNIDs can appear in many forms. We suggest the following typology of usage and best practices:
numismatics.org:1858.1.1
Placing this string in a web-page will allow that page to appear in response to a search for the DNID.
<a href="http://numismatics.org/dnid/numismatics.org:1858.1.1">numismatics.org:1858</a>
This HTML will associate a DNID with a representation of the object.
<span property="dnid:dnid" content="numismatics.org:1858.1.1">numismatics.org:1858.1.1</span>
RDFa is a W3C standard that allows semantic attributes to be attached to any xhtml element. These attributes also appear in the metainformatioin attributes module of the XHTML 2.0 working draft.
Using RDFa does allow the content of a html/xhtml anchor element to be something other than the DNID:
<a property="dnid:dnid" content="numismatics.org:1858.1.1" href="http://numismatics.org/dnid/numismatics.org:1858.1.1">the first coin donated to the ANS</a>
This is not a preferred usage.
A combination of html-encoded and RDFa-encoded representations is a suggested best-practice:
<a href="http://numismatics.org/dnid/numismatics.org:1858.1.1" property="dnid:dnid" content="numismatics.org:1858.1.1">numismatics.org:1858.1.1</a>
Uniform Resource Names (URNs) are a form of resource identifier intended to be persistent and location-independent (RFC 1737, RFC 2141). A DNID can be represented in the form of a URN by using the prefix “urn:dnid:”.
urn:dnid:numismatics.org:1858.1.1
URN namespaces are assigned by the IANA. Many entities have created URN namespaces on an informal basis and “urn:dnid” is comparable to these.
The most complete implementation of the DNID system is at the American Numismatic Society. This article provides a preliminary discussion of the ability of DNIDs to be “author activated” and “bidirectional”.
As defined in part by Wikipedia, "Collaborative Tagging", also known as “Social Bookmarking” and other related terms, is “the practice and method of collaboratively creating and managing tags to annotate and categorize content.” By this definition, DNIDs are tags by which users can make unambiguous reference to web accessible descriptions of discrete entities.
This blog post mentions an ANS coin with the DNID numismatics.org:1949.100.10 . It is now the case that if you search for that DNID, the post will appear. This search can also be initiated from the ANS website by clicking on “Find pages that refer to this ANS object”.
The blog for DNID-Community is at http://dnid-community.blogspot.com/.
This site is maintained by Sebastian Heath (sebastian<dot>heath<at>gmail<dot>com) and Neel Smith (nsmith<at>holycross<dot>edu). The content of the site has benefited from discussion on the Antiquist e-mail list.