Post on 08-Jan-2016
description
Linking electronic documents and standardisation of URL’s
What can libraries do to enhance dynamic linking and bring related information within a distance of “only one click”?
Koninklijke Bibliotheek, Nationale bibliotheek van Nederland
Theo van Veen
Linking digital objects and standardisation of URL’s
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
Koninklijke Bibliotheek, Nationale bibliotheek van Nederland
Request
Response
OpenUrl HTML, javascriptOpenUrl XML, javascript
XML XML, javascript
(dynamic) url’s HTML, javascript
telnet,VT100 ASCII
Z39.50 Z39.50
scripting screensteeling
http to Z39.50 Z39.50 to http
Trend
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
Koninklijke Bibliotheek, Nationale bibliotheek van Nederland
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.
OpenUrl (simplified) OpenUrl=Base-url + query with standardised syntax
Example:Base-url: http://my.pc.com/request?
Query: issn=12345678&year=2000&vol=8&spage=123 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
Personal link page Metadata from anywhere link to any
system of the user’s 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 user’s browser: no server needed!
Koninklijke Bibliotheek, Nationale bibliotheek van Nederland
Koninklijke Bibliotheek, Nationale bibliotheek van Nederland
Personal Link Page
Query
Koninklijke Bibliotheek, Nationale bibliotheek van Nederland
Personal Link Page
Response with javascript to allow setting the base url to personal link page.
Koninklijke Bibliotheek, Nationale bibliotheek van Nederland
Personal Link Page
Next responses will show personal link page as default for openURL link.
PLP
Personal, context dependent, dynamically generated links
Base-url points to plp
Record display with option to select personal link page
Koninklijke Bibliotheek, Nationale bibliotheek van Nederland
Example of personal link page for articles
Koninklijke Bibliotheek, Nationale bibliotheek van Nederland
Result obtained via PLP
Koninklijke Bibliotheek, Nationale bibliotheek van Nederland
Example of personal link page for books
Koninklijke Bibliotheek, Nationale bibliotheek van Nederland
HTML-page to create plp
Koninklijke Bibliotheek, Nationale bibliotheek van Nederland
HTML page with Javascript to get issn from openurl and present a link
Koninklijke Bibliotheek, Nationale bibliotheek van Nederland
<html>
<script>
srch=unescape(location.search);
srch=srch.substring(1,999);
sarray=srch.split("&");
issn="";
for (i=0 ; i<sarray.length ; i++)
{
ind_key=sarray[i].split("=");
if (ind_key[0] == "issn") issn=ind_key[1];
}
function search()
{
if (issn== "") alert("No issn");
else location="http://hognose.kb.nl/cgi-bin/gurl2url.pl?issn=" + issn
}
</script>
This is a very simple example of a personal link page. Click <a href="javascript:search()"> here </a>to search on issn.
</html>
Additonal XML-metadata
Koninklijke Bibliotheek, Nationale bibliotheek van Nederland
Query
ResponseNO HITSExample : Response with terms that are most alike (fuzzyness)
Fuzzy matching terms:
•Term 1•Term 2•Term 3•Term 4•Term 5
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
Additional data in XML
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Query to different targetsResponses from different targetsFuzzy results
Short title listNo hits
Index browseIndex browseFuzzy resultsRelated terms
Integration of the results allows the user to improve his query and retry a distributed search
Example of additional responses XML
<response><number-of-hits>0</number-of-hits><fuzzy-list> <fuzzy-term>abc</fuzzy-term> <fuzzy-term>bcd</fuzzy-term></fuzzy-list><scan-list> <scan-term>abc</scan-term> <scan-term>acc</scan-term></scan-list></response>
Koninklijke Bibliotheek, Nationale bibliotheek van Nederland
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/query?keyword=test&request=<fuzzy-list>
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
Koninklijke Bibliotheek, Nationale bibliotheek van Nederland
Remarks:
1. Not all references have a DOI
2. User may not have access to DOI-resolver
3. User may not have access to locations specified by the metadata from DOI-agent
4. The DOI identifies but does not localise objects
Retrieval of electronic references
Koninklijke Bibliotheek, Nationale bibliotheek van Nederland
Query ?
Article
Reference 1Reference 2Reference 3
Search for referenced article
Referenced articlePersonal
link pageresolvedbase-url(resolution)
Retrieval of electronic references
Koninklijke Bibliotheek, Nationale bibliotheek van Nederland
Electronic references: what can libraries do?
Convert references via XML or HTML to OpenUrl’s
Maintain a local list of journals with the base-url of their locations
Forward the user’s query to new base-url for journals that are on other locations.
Koninklijke Bibliotheek, Nationale bibliotheek van Nederland
Distributed query (Z39.50)
Koninklijke Bibliotheek, Nationale bibliotheek van Nederland
Distributed query to the “whole world”
user query
Central index (web search engines)
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Harvesting of the “whole world”
user query
Selective query propagation
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Distributed search to selected targets
user query
subject y geographicalownershipsubject x
Selective query propagation (hybride solution)
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target selection for subject x
subject y geographicalownershipsubject x
Distributed query to selected targets
query to gateway or to selected targets directly
Central index (OAI-protocol ?)
Multi target search
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1. Search for : dutchess art search*
2. Enter new search e.g. Rembrandt
3. Query will be send to all searchable targets
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.
Koninklijke Bibliotheek, Nationale bibliotheek van Nederland
Fields to be used in URL to request digital objects:
1. Identification of object (oid)
2. Role (standardised)
Examples:
http://dnep.kb.nl/openurl?oid=kb:1234&role=thumbnail http://dnep.kb.nl/openurl?oid=kb:1234&role=table-of-contents
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 Let’s 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