Subject: [urn] Maintenance of the URN namespace registrations

From: Juha Hakala <[email-masked]>
Date: Tue, 26 Oct 2010 15:57:17 +0300

Hello all,

Library & publisher communities have registered a number of URN 
namespaces over the years, including namespaces ISBN and ISSN for the 
well-known international standard identifiers for books and serials.

International standards do not change too often in fundamental ways, but 
by coincidence both the new ISBN used since 2007 and the new ISSN 
version released in 2007 deviated from their predecessors in such a way 
that the need to revise RFCs registering their namespaces arose - but in 
different ways.

With ISBN the function of the identifier is still the same, but the 
syntax of the identifier has changed. The old ISBN had 10 digits, the 
new one 13, starting with prefix 978 or 979. This has an impact on how 
the ISBNs are resolved as URNs. The Internet draft written by Maarit 
Huttunen, Alfred Hoenes and myself (see 
http://tools.ietf.org/html/draft-hakala-rfc3187bis-isbn-urn-00) 
describes how to deal with ISBN-13.

With ISSN the syntax of the identifier is still the same, but the ISSN 
functions have changed. Traditional ISSN, which identifies a single 
manifestation of a journal, such as e-version of Scientific American, is 
still there. But the standard defines also something new called Linking 
ISSN. This new identifier will bring together all manifestations of a 
journal.

Syntactically, ISSN-L and ISSN are identical. In practice, ISSN of the 
first manifestation of the journal has a dual role; it is also used as 
the ISSN-L.

In library systems, ISSN and ISSN-L reside in the same bibliographic 
record, but they are stored in different data elements. ISSN-L appears 
in every manifestation of the journal, alongside the ISSN belonging to 
that particular manifestation.

Although ISSN and ISSN-L of the journal are identical, but in library 
system they can be indexed separately (being stored in different 
metadata elements). Thus the library system knows that the two identical 
numbers have different semantics. When searched as ISSN the identifier 
will only retrieve the eldest manifestation of the serial. When searched 
as ISSN-L the user should be able to find all manifestations.

In URN resolution, something has to make it obvious to the URN resolver 
whether the user wants to resolve the number as ISSN or ISSN-L. Given 
the current URN architecture, one way to accomplish this is to register 
two namespaces, ISSN and ISSN-L. Then, in order to resolve 1234-5678 as 
ISSN URN:ISSN will do, and to resolve it has ISSN-L, URN:ISSN-L would 
do. The former query would yield bibliographic metadata about the 
relevant manifestation or its URL, the latter bibliographic metadata 
about all manifestations. There can be several of them, since journals 
increasingly have both printed and e-versions.

Revision of RFC 3044 has not yet started, but Persid project has been in 
contact with the ISSN International Centre on how, when and by whom such 
revision can be accomplished.

Both ISSN and ISBN were developed in 1970s. These recent revisions were 
the first ones that do require URN namespace registrations. All previous 
edits were minor and did not change syntax or the functionality of the 
identifier in a fundamental manner. Thus it would not be right to draw a 
conclusion that identifier standards are in general volatile and that 
this will force us into changing namespace registrations every now and 
then. More likely, the revisions having implications to the namespace 
registrations will be rare events - unless the practice of resolving the 
URNs in the namespace in question shows that the namespace registration 
has to be modified in some manner. This is what happened with the NBN 
(national bibliography number). When the RFC was written, there were no 
NBN-based URNs, while now there are millions of them. Practical 
experienced gained have been used in the preparation of the revised 
namespace registration, available at
http://www.ietf.org/id/draft-hakala-rfc3188bis-nbn-urn-00.txt.

Best regards,

Juha Hakala
-- 

  Juha Hakala
  Senior advisor, standardisation and IT

  The National Library of Finland
  P.O.Box 15 (Unioninkatu 36, room 503), FIN-00014 Helsinki University
  Email [email-masked], tel +358 50 382 7678

---

From: Keith Moore <[email-masked]>
Date: Tue, 26 Oct 2010 10:06:59 -0400

On Oct 26, 2010, at 8:57 AM, Juha Hakala wrote:

> In URN resolution, something has to make it obvious to the URN resolver whether the user wants to resolve the number as ISSN or ISSN-L. Given the current URN architecture, one way to accomplish this is to register two namespaces, ISSN and ISSN-L. Then, in order to resolve 1234-5678 as ISSN URN:ISSN will do, and to resolve it has ISSN-L, URN:ISSN-L would do. The former query would yield bibliographic metadata about the relevant manifestation or its URL, the latter bibliographic metadata about all manifestations. There can be several of them, since journals increasingly have both printed and e-versions.

Another way to accomplish this would be to have the resolution mechanism return metadata of the form (forgive my pseudo-XML):

<ISSN metadata>
   metadata applicable when using this name as an ISSN go here
</ISSN metadata>
<ISSN-L metadata>
   metadata applicable when using this name as an ISSN-L go here
</ISSN-L metadata>

...and let the caller decide whether it wants to use one or both sets of metadata.

But I dislike having two different URN name spaces.    I think this is more a case of a single set of names being used in two different contexts than a case of different name spaces.

Keith

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From: "Martin J. Dürst" <[email-masked]>
Date: Wed, 27 Oct 2010 18:52:45 +0900

Hello Juha,

I was almost able to follow your explanations, but it would help me (and 
maybe others) a lot if you could give some concrete examples of 
"manifestation of the journal".

Regards,   Martin.

-- 
#-# Martin J. Dürst, Professor, Aoyama Gakuin University
#-# http://www.sw.it.aoyama.ac.jp   mailto:[email-masked]

---

From: Juha Hakala <[email-masked]>
Date: Wed, 27 Oct 2010 14:31:11 +0300

Hello Martin,

In order to give a proper understanding of what manifestation means, I 
need to start a little bit further away.

Library community has develop a model (Functional Requirements for 
Bibliographic Records, FRBR) which has four levels:

1. Work, such as Joyce's Ulysses
2. Expression, for instance Finnish translation of Ulysses
3. Manifestation, e.g. paperback version of the Finnish translation of 
Ulysses, or printed version or Web version of Scientific American.
4. Item, a copy of the aforementioned manifestation of Ulysses or set of 
Scientific American volumes in my book shelf.

Traditional library identifiers such as ISBN and ISSN deal with 
manifestations. Usually every one of them, for instance hardcover book, 
paperback book and e-book should get a different ISBN. Whenever an 
e-book is migrated to guarantee its usability, the new version should 
get a new ISBN. These practices are spesified in the identifier 
standards (but are not always followed properly by those responsible of 
the identifier assignment). URN inherits these community practices from 
the namespace level.

There are standard identifiers for works, such as International Standard 
Text Code (ISTC) for textual works. ISTC and its peers (ISAN, ISWC) do 
not have URN namespaces yet.

 From the national library's point of view, eventually (after 200 years 
of storage, for instance) there will be a lot of digital manifestations 
for each (born digital or digitized) work, created via successive 
migrations within the library's long term preservation system (old 
versions will not be deleted from the system). These manifestations will 
ideally be linked directly to one another and to the work level record, 
if one exists. Some manifestations may still be readable, while some 
others may not / will not be.

Any persistent identifier system to be used in this environment must 
support a broad set of services. For instance, if the URN belongs to a 
work, it must be possible to retrieve bibliographic data related to the 
manifestations of this work, or data related to a specific manifestation 
(for instance the first or the latest) of the work, or bibliographic 
data about items related to given / all manifestations.

Best regards,

Juha

-- 

  Juha Hakala