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<p>Hi James,</p>
<p>Fortunately (or unfortunately) I have had quite a few thoughts on
the matter. I have done my best to keep them to the point.<br>
</p>
<p>First, I don't think it is possible to account for the same item
being in multiple repositories. As an individual institutional
repository owner you have no control over other institutional
repositories who may have shared authors on publications and have
the right to make the same publication available on their
institutional repositories. Having a background in the Semantic
Web, trying to determine if two things with different unique
identifiers are actually the same thing is a near impossible
problem to solve definitively. The best you can do is ensure the
same unique identifier is not somehow used for two different
things and also avoid creating and using more unique identifiers
than are absolutely necessary.</p>
<p>EPrints has always had a unique identifier in the form of a URI
(e.g. <a class="moz-txt-link-freetext" href="https://eur03.safelinks.protection.outlook.com/?url=http%3A%2F%2Feprints.example.org%2Fid%2Feprint%2F123&data=04%7C01%7Ceprints-tech%40ecs.soton.ac.uk%7C77295f4a36d24085692708d90a2b1889%7C4a5378f929f44d3ebe89669d03ada9d8%7C0%7C0%7C637552002514220749%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=mppuRMTj6lsZnbgXaKiuD0tfcdsbG7IaTm3XTJQvN3s%3D&reserved=0" originalSrc="http://eprints.example.org/id/eprint/123" shash="HkcVRe+t9ifhx1edoCw4RKVg7PBApqsg5eEp/QbvC495N7b0gft12HmraaF4xm4lklWAt8fzzqUA9l3X6eDTyzoDLfcYPMrAbIbULXbGkHZwLWngXH7DzZ6bYx7aFJW8RhPsv1UO+POCl+tdmGRwX5wRE7LuONUgBNprsbGFyjk=">http://eprints.example.org/id/eprint/123</a>). I would suggest
this is the most appropriate unique identifier to use as every
item in your repository will have one but not every item will
necessarily have a DOI or similar unique identifier. You could
configure your repository to use a DOI minting service (e.g. data
repositories often use DataCite) but this rather breaks the rule
of creating more unique identifiers than are absolutely
necessary. <br>
</p>
<p>One potential problem I have noted with EPrints URIs is that
these were all originally http but if you modify you HTTPS
configuration to ensure HTTPS is used everywhere, then these URIs
will likely also be changed to https, making them non-persistent
which is another big no-no. For this reason, early on in EPrints
3.4 I introduced a configuration properly 'uri_url' to ensure that
you could modify a repository's HTTPS configuration but if you had
this configuration option set you could keep the URIs as http. As
in the context of being a unique identifier, you need to consider
the URI as being a string of characters and if this string of
characters changes, then it is no longer the same unique
identifier, even though it is still describing the same thing. <br>
</p>
<p>I think you also identified another potential problem with the
structure of an EPrints URI, which is if there is a change to the
hostname of the repository itself. Again the uri_url option
should allow you to ensure URIs do not change. Unfortunately,
this may lead to confusion for users who wonder why the hostname
for these URIs is different to the hostname of the repository.
Also, depending what happens to the old hostname's DNS
registration these URIs may become unresolvable. However, there
is no requirement for URIs, as any unique identifier, to be
resolvable.<br>
</p>
<p>If an item has a DOI provided by a journal, an ISBN provided by a
book publisher, etc. then this would typically be more useful than
an institutional repository's URI, as this would be used in a
general context (i.e. you would expect a DOI or ISBN to appear in
the citation for such an item). However, I think to provide the
best possible coverage there is need for both forms for unique
identifier: the one from the original publisher (if that is not
the institutional repository, which would likely be the case for
theses, etc.) and one from the institutional repository. If you
provide export formats that can be ingested by third-party
applications that include both unique identifiers and therefore
build a link between the two, it is possible to build and network
of unique identifiers for a particular item. Then when you get a
journal article that has authors from multiple institutions, it
will be possible to see that a publication from institution A is
the same publication as from institution B.</p>
<p>Regards</p>
<p>David Newman<br>
</p>
<p><br>
</p>
<p>On 28/04/2021 10:02, James Kerwin via Eprints-tech wrote:<br>
</p>
<blockquote type="cite" cite="mid:EMEW3|78d372fc7a2e0bf131f446655293956ax3RA3j14eprints-tech-bounces|ecs.soton.ac.uk|CAKkNZ9BSXLBgD0SKnDo+Xdk66z7YVefph1y=bJi_zGGJJgvpRA@mail.gmail.com">
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<div>
<div dir="ltr">Hi All,<br>
<div><br>
</div>
<div>For once I have not broken anything, just looking for
opinions and advice.</div>
<div><br>
</div>
<div>As part of Plan S we need to have persistent identifiers
for scholarly publications. I have read this EPrints wiki:<br>
<br>
<a href="https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwiki.eprints.org%2Fw%2FPlan_S&data=04%7C01%7Ceprints-tech%40ecs.soton.ac.uk%7C77295f4a36d24085692708d90a2b1889%7C4a5378f929f44d3ebe89669d03ada9d8%7C0%7C0%7C637552002514220749%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=8y2b3nrmxD7PBU08cffAImvkP8cOFnbu9tubx1SggxQ%3D&reserved=0" originalSrc="https://wiki.eprints.org/w/Plan_S" shash="QwOx0KjvfhmYJDDEzrt7ji/MvfeQ+q+gOY2W2rN4JndNp0TmCIyya1nGHXJsCI0ALjQ6JLIjfiCeZwVX6RlL3gPk+ufUXvZ6PD80vu2FO87W7PfR0/+TJ//N4ShD3A2JwcFDDy7WunaFcGwBErDkUlMOM37h/rvFjKxXiE1WV40=" originalsrc="https://wiki.eprints.org/w/Plan_S" shash="go4cYmWcvVK0jyHiciI4Z35ZKw+zZNjb3PfrQE9ir7LIcNhJbkhXba3HU1JzePX3Rt4hNvEbOJ+bB7O1gTUuGzAB14iuAsqbSUTJlryzP5jHKnVJol9U+RfuIPQgIgtPBXsYgh8l5yy/8JP4XuatjwPYupW30vWPOR7qv/NkuIE=" moz-do-not-send="true">https://wiki.eprints.org/w/Plan_S</a><br>
</div>
<div><br>
</div>
<div>At Liverpool we aren't 100% sure about this topic. DOI
would be the obvious choice, but there are some on my team
who reasonably point out that the same item could be in
several repositories and end up having several separate DOIs
associated with it. I'm not sure how much that matters.<br>
<br>
Does anybody have any thoughts on this point? We spoke with
my predecessor, Adam, who was really helpful. Unconvinced
team members have suggested using
<a href="https://eur03.safelinks.protection.outlook.com/?url=http%3A%2F%2Fhandle.net%2F&data=04%7C01%7Ceprints-tech%40ecs.soton.ac.uk%7C77295f4a36d24085692708d90a2b1889%7C4a5378f929f44d3ebe89669d03ada9d8%7C0%7C0%7C637552002514230699%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=b80XBZi8kOEk1Pr5%2F%2FwQySzqR8aqj2HSQQumHxeWVeM%3D&reserved=0" originalSrc="http://handle.net/" shash="xO678dcPaEtLOFIbQ4XDV+xHaVljwtyeTUmOH+c1Z/NPoc5rzWfcFDsvq/h7VjTfxNOhKGr5xbdKBJ7ma4Spv1z2d/x/4SRVgzqPcq4WBxdxH6/K9MWCWNOHK5fqg3F+qwO/f2qpEwJHCsCaOHB3DpJxCdDmhoqH0oy9jZzB/1s=" originalsrc="http://handle.net/" shash="ydX9Isj6MHUAjs48+qIKt2VHdtonMpHUDYR5Zn9ozh67sTk/v7lP+NJ2bGF/vItcGikmscUHRyVa+ZV8hE4nQpP5C6fLmexlQsLXVfzypi+683kRXyVzOKc62JSTm5o+BuUfoV73ZI5PxMMLOq9wnE5yf/BMUyRnwDghX48nDIg=" moz-do-not-send="true">handle.net</a> which I think is
overkill and doesn't necessarily meet the needs of Plan S in
itself.<br>
<br>
Also, the URL/EPrints ID for each item, is this not a
suitable persistent identifier? The wiki linked above does
mention this. There's always the possibility a repository
URL could change in the future, but I would expect some sort
of redirect to overcome this.</div>
<div><br>
</div>
<div>If there is a more suitable place for this type of
discussion please send me there.<br>
</div>
<div><br>
</div>
<div>Thanks,</div>
<div>James</div>
</div>
</div>
<br>
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