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1.7 has alternative
ExplanationSizeOrderValue SpaceDatatypeThe references resource presents the intellectual content of all or part of the described resource, often in another access mode.0..*UnspecifiedRepertoire of ISO/IEC 10646-1:2000Character-StringIt is possible that a number of alternative resources exist that can substitute for all or some of the described resource, and, also, that one alternative substitutes in a different way than another. If a resource has more than one alternative, the element should be repeated. For example, one alternative may possess captions (for people with hearing impairments), whereas another contains described video (for people with visual impairments). Three alternatives for a digital video about Marshall Mcluhan, one with English captions, one with French, and one with French described video would each have a separate entry and element.
It is expected that there will be local implementations of this element that invoke or use subelements that may use a nested approach. For example, one implementation using IEEE-LOM may use, 1.1 identifier, 1.1.1 catalog and 1.1.2 entry as a unique way to identify the component resource:
hasalternative
1.1 identifier
1.1.1 catalog
1.1.2 entry
Such an implementation may look like the following:
URL http://www.cancore.ca
A Dublin Core implementation would use the definition of identifier as, "An unambiguous reference to the resource within a given context". An example may look like,
If this element is absent, then the resource has no alternatives.
Vocabulary Recommendations
CanCore recommends that the vocabulary values for this element include, but not be limited to, URI, URL, URN, PURL and DOI.
The recommended values are as follows:
URI Uniform Resource Identifier: HYPERLINK "http://www.w3.org/Addressing/" http://www.w3.org/Addressing/ A character string used to identify a resource (such as a file) from anywhere on the Internet by type and location (e.g., HYPERLINK "http://www.cancore.ca" http://www.cancore.ca, HYPERLINK "ftp://www.ibm.com" ftp://www.ibm.com). The document "RFC2396" defines the generic syntax of URI, and provides guidelines for their use (see HYPERLINK "http://www.ietf.org/rfc/rfc2396.txt" http://www.ietf.org/rfc/rfc2396.txt).
URL Uniform Resource Locator: HYPERLINK "http://www.w3.org/Addressing/URL/Overview.html" http://www.w3.org/Addressing/URL/Overview.html An informal name for addresses associated with the Web and other common Internet protocols (e.g., HYPERLINK "http://www.cancore.ca" http://www.cancore.ca, HYPERLINK "ftp://129.128.193.212" ftp://129.128.193.212).
URN Uniform Resource Name: HYPERLINK "http://www.ietf.org/rfc/rfc2141.txt" http://www.ietf.org/rfc/rfc2141.txt "A particular scheme, urn:, specified by RFC2141 and related documents, intended to serve as persistent, location-independent, resource identifiers." (See HYPERLINK "http://www.w3.org/Addressing/" http://www.w3.org/Addressing/). ISBNs may be incorporated or included here, for example, urn:isbn:xxx-xxx-xxx.
PURL Persistent Uniform Resource Locator: HYPERLINK "http://purl.oclc.org/" http://purl.oclc.org/ Functionally, a PURL is a URL. However, instead of pointing directly to the location of an Internet resource, a PURL points to an intermediate resolution service. The PURL resolution service associates the PURL with the actual URL and returns that URL to the client. The client can then complete the URL transaction in the normal fashion. In other words, this is a standard HTTP redirect. PURLs satisfy many of the requirements of URNs, but they do not allow for complete location independence.
DOI Digital Object Identifier: HYPERLINK "http://www.doi.org/" http://www.doi.org/ A system for identifying and exchanging intellectual property in a distributed, digital environment, developed in part by the Association of American Publishers. DOIs have been widely implemented in some contexts, including publishing and government, and are being considered by some educational infrastructure initiatives. DOI systems also provide some digital rights management features. Their use, however, may involve some upfront costs.
Example
Has alternative:
http://www.somewhere.org/captions_en/mcluhan.mov
XML Example
URI
http://www.somewhere.org/captions_en/mcluhan.mov
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