rplante at poplar.ncsa.uiuc.edu
Thu Sep 11 07:58:11 PDT 2003
As Arnold outlined, there is an important driver for persistant,
location-independent identifiers coming from the journals, and I think it
is important we try to get some compatibility between the IVOA and ADEC.
To be a bit more precise, the IVOA Identifier WD describes
organization-dependent identifiers. That is, as long as a single
organization continues to curate a resource, it can freely move its
location or mirror it at several locations (perhaps hiding these details
behind a single interface) without changing the resource's IVOA
However, if curation of a resource is transfered to another organization,
or if another organization decides to curate the resource, it is
considered a new instance of the resource; thus, it will have a different
identifier and metadata description.
Given that we need to distinguish between different instances of a
resource, I believe we need to have a second type identifier to handle
location independence. There is precedence in the internet world for this
in the distinction between URIs and URNs. The latter is what we need;
however, it would help if they were related in some way.
Here's my strawman, with many details missing:
1. we create metadata that allows resource descriptions to say:
* "I am a mirror of this other resource"
* "The following resources are recognized mirrors of me"
2. When a new standard service is defined, it should include an
explanation of what it means for two instances of that service to be
3. Resources use the metadata from #1 to claim a mirror relationship.
4. #3 is not sufficient, because when we have mirrors of mirrors, it is
difficult to traceback through all the relationships. All mirrors
should share a common URN; when someone mirrors another resource,
they adopt that URN.
5. Journals can use the URN to cite datasets in articles.
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