Linking electronic documents and standardisation of URLs

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Linking electronic documents and standardisation
of URLs
Linking digital objects and standardisation of
URLs

• What can libraries do to enhance dynamic linking
  and bring related information within a distance
  of only one click?

Theo van Veen
Koninklijke Bibliotheek, Nationale bibliotheek
van Nederland
2
What can libraries do?

• Standardisation and agreements
• Personal linking page (SFX and OpenUrl)
• Offer additional query responses in XML
• Conversion of references in electronic documents
  to OpenUrl (DOI, CrossRef)
• Local resolution and redirection of OpenUrl
• Disclosure of searchable sites (harvesting,
  OAI-protocol and deep linking)

Koninklijke Bibliotheek, Nationale bibliotheek
van Nederland
3
Trend
Request
telnet,VT100 ASCII

scripting
screensteeling
Z39.50 Z39.50

(dynamic) urls HTML,
javascript
http to Z39.50 Z39.50
to http
OpenUrl HTML, javascript
OpenUrl XML, javascript
XML XML,
javascript
Response
Koninklijke Bibliotheek, Nationale bibliotheek
van Nederland
4
Aspects in standardisation

• What do we want ?
• High degree of interoperability
• Low barrier implementation
• High level of automation
• How (besides reaching agreements)?
• Extendibility Do not reject a response with
  items that are not (yet) in the standard
• Tolerance Do not reject a response if items are
  missing if it is not fatal
• Flexibility Try to allow responses that are not
  requested
• Do not rely on negotiation between http server
  (take it or leave it) and browser (make the
  best of what it gets)
• Keep it simple

Personal remark As interaction between systems
becomes more complex and is moving all the time,
standardisation of request and response might
require a more non-conventional approach.
Koninklijke Bibliotheek, Nationale bibliotheek
van Nederland
5
OpenUrl (simplified)

• OpenUrlBase-url query with standardised syntax
• Example
• Base-url http//my.pc.com/request?
• Query issn12345678year2000vol8spage123
• Usage
• Dynamic and automatic generation of just in
  case links depending on current metadata and
  user preferences.
• Link request for service, search or object

Koninklijke Bibliotheek, Nationale bibliotheek
van Nederland
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Personal link page

• Metadata from anywhere link to any system of the
  users choice
• Let the user set his own base-url (by means of a
  cookie)
• Allow the user to set this base-url when
  presenting the metadata (only one click away)
• The personal link page can analyse the query-part
  of the OpenUrl in the users browser no server
  needed!

Koninklijke Bibliotheek, Nationale bibliotheek
van Nederland
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Personal Link Page
Query
Koninklijke Bibliotheek, Nationale bibliotheek
van Nederland
8
Personal Link Page
Response with javascript to allow setting the
base url to personal link page.
Koninklijke Bibliotheek, Nationale bibliotheek
van Nederland
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Personal Link Page
Personal, context dependent, dynamically
generated links
Next responses will show personal link page as
default for openURL link.
Base-url points to plp
PLP
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van Nederland
10
Record display with option to select personal
link page
Koninklijke Bibliotheek, Nationale bibliotheek
van Nederland
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Example of personal link page for articles
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van Nederland
12
Result obtained via PLP
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Example of personal link page for books
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HTML-page to create plp
Koninklijke Bibliotheek, Nationale bibliotheek
van Nederland
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HTML page with Javascript to get issn from
openurl and present a link
lthtmlgt ltscriptgt srchunescape(location.search) sr
chsrch.substring(1,999) sarraysrch.split("")
issn"" for (i0 iltsarray.length i)
ind_keysarrayi.split("") if (ind_key0
"issn") issnind_key1 function
search() if (issn "") alert("No issn") else
location"http//hognose.kb.nl/cgi-bin/gurl2url.pl
?issn" issn lt/scriptgt This is a very simple
example of a personal link page. Click lta
href"javascriptsearch()"gt here lt/agtto search on
issn. lt/htmlgt
Koninklijke Bibliotheek, Nationale bibliotheek
van Nederland
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Additonal XML-metadata
Koninklijke Bibliotheek, Nationale bibliotheek
van Nederland
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Additional responses

• Related terms
• Results of fuzzy matching
• Index browse (z39.50 scan)
• Short title list
• Number of hits for each term
• Etc.

Koninklijke Bibliotheek, Nationale bibliotheek
van Nederland
18
Additional data in XML
Fuzzy results
Short title list
No hits
Index browse
Index browse Fuzzy results Related terms
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van Nederland
19
Example of additional responses XML

• ltresponsegt
• ltnumber-of-hitsgt0lt/number-of-hitsgt
• ltfuzzy-listgt
• ltfuzzy-termgtabclt/fuzzy-termgt
• ltfuzzy-termgtbcdlt/fuzzy-termgt
• lt/fuzzy-listgt
• ltscan-listgt
• ltscan-termgtabclt/scan-termgt
• ltscan-termgtacclt/scan-termgt
• lt/scan-listgt
• lt/responsegt

• For new tags that are not know to the client
• Adapt XSL (and/or javascript) to display this
  item
• The user application may try to ask for this new
  tag (using the same name) in automatic generated
  urls.

Example of requesting URL http//www.demo.nl/quer
y?keywordtestrequestltfuzzy-listgt
Koninklijke Bibliotheek, Nationale bibliotheek
van Nederland
20
Electronic references, DOI and Crossref

• Author submits article
• Publisher resolves references
• Publisher submits metadata to DOI-agent and
  receives DOI for referenced articles
• Publication is issued
• User requests publication
• User clicks on DOI of reference (link to
  DOI-resolver)
• DOI-resolver presents DOI metadata
• User selects location from DOI metadata
• User requests article from that location

• Remarks
• Not all references have a DOI
• User may not have access to DOI-resolver
• User may not have access to locations specified
  by the metadata from DOI-agent
• The DOI identifies but does not localise objects

Koninklijke Bibliotheek, Nationale bibliotheek
van Nederland
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Retrieval of electronic references
Article Reference 1 Reference 2 Reference 3
Query ?
Referenced article
Search for referenced article
Personal link page
resolved base-url (resolution)
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van Nederland
22
Retrieval of electronic references
Koninklijke Bibliotheek, Nationale bibliotheek
van Nederland
23
Electronic references what can libraries do?

• Convert references via XML or HTML to OpenUrls
• Maintain a local list of journals with the
  base-url of their locations
• Forward the users query to new base-url for
  journals that are on other locations.

Koninklijke Bibliotheek, Nationale bibliotheek
van Nederland
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Distributed query (Z39.50)
Distributed query to the whole world
user query
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25
Central index (web search engines)
Harvesting of the whole world
user query
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Selective query propagation
geographical
subject y
ownership
subject x
Distributed search to selected targets
user query
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27
Selective query propagation (hybride solution)
geographical
subject y
ownership
subject x
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28
Multi target search

• Search for dutchess art search
• Enter new search e.g. Rembrandt
• Query will be send to all searchable targets

Koninklijke Bibliotheek, Nationale bibliotheek
van Nederland
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Metadata and digital objects

• Separation of metadata and digital objects
  (different databases)
• Metadata independent from digital objects (no
  hardcoded file names in bibliographic metadata)
• Structure of digital objects not always known
  (e.g. subject to change e.g. due to preservation
  activities)
• Digital objects can be anything (from single file
  to database of streaming objects)
• Request is not always the whole digital object
  but a role thumbnail, table of contents, title
  page etc.

• Fields to be used in URL to request digital
  objects
• Identification of object (oid)
• Role (standardised)

Examples http//dnep.kb.nl/openurl?oidkb1234ro
lethumbnail http//dnep.kb.nl/openurl?oidkb1234
roletable-of-contents
Koninklijke Bibliotheek, Nationale bibliotheek
van Nederland
31
Conclusions and recommendations

• Make your services OpenUrl-compatible
• Focus on XML for the presented results and as
  transfer format
• Implement the small piece of javascript to allow
  setting of the plp
• Lets come to agreements on extension of OpenUrl
  to allow for fast and low barrier
  implementation of extra services and searches.

Koninklijke Bibliotheek, Nationale bibliotheek
van Nederland