BALSA by xumiaomaio


An OpenURL resolver for services in
 the JISC Information Environment

 JISC joint programme meeting, 22 May 2003, Warwick
              What is Balsa?
• An OpenURL resolver service developed by
  EDINA within the ZBLSA project
• Part of the Join-Up cluster within the JISC 5/99
• The Join-Up projects have a common interest in
  providing integrated services on journal articles
• Within the 'demand-side' model: Discover, Locate,
  Request, Access, Balsa fulfils the Locate function
Problem: locating journal articles
• Wide range of resources for discovery:
   – A&I databases
   – Electronic table of contents services
• Wide range of resources for access:
   – Full text of journal article from many vendors
   – Shelf copy from institutional library
   – Copy by ILL
• BUT, not always simple for a user to locate an
  access service for a discovered article
          Early linking solutions
•     discover                                  access

      A&I database                               Full text service
• Pros
    – One click from discovery to access
    – No institutional configuration required
• Cons
    – No customisation for institution's preferred provider
      (appropriate copy problem)
    – Links to a single rather than multiple services
    – Links expire
    Dynamic link resolution by broker
        (OpenURL resolution)
•      discover       locate       access

     A&I database               full text service


     Subject portal    broker
                                 Union catalogue

    Library portal
                                document delivery
         Balsa broker operation
• Balsa receives locate request from user:
   – Bibliographic descriptor for the information object
   – Indication of user's institutional affiliation
• Determines service locations that contain the
  object, and for which the user has rights
   – By a priori knowledge of holdings and rights
     (configuration), or
   – By query (e.g. search the OPAC)
• Presents service options to the user as a set of
    Key standard: the OpenURL
• Link designed for dynamic resolution, appropriate
  for the requesting user
• A URL with two components:
   – The base URL (the address of the user's broker)
   – Payload (bibliographic descriptor for the information
• Examples:
            OpenURL features
• Standard URL
   – Basic unit of currency on the Web for linking
   – Easy to generate and manipulate
• Widespread acceptance by the industry
• Forthcoming NISO standard (version 1.0)
• Relevant to any discovery service that provides
  links to articles (not just A&I databases):
   – Library portals, L&T materials, departmental Web
     sites, reading lists, etc., etc.
              Balsa standards
• OpenURL
• Z39.50
  – Only widely available means of accessing library
    catalogues and ToC services
  – Used by the broker to provide the user with links to
  – Standard mechanism for accessing full text services
• Balsa Rights Evaluation Mechanism (REM)
      Broker operation revisited
• Determines service locations by ensuring:
   – The service holds the item
   – The user has access rights
• Two possible approaches:
   – By a priori knowledge of holdings and rights
     (configuration), or
   – By query (REM or OPAC search) in real time
• Most commercial OpenURL resolvers use the first
  method; Balsa uses the second
                    Balsa REM
• Balsa issues a REM query to each service,
  comprising the bibliographic descriptor + the
  identity of requesting user's institution
• Possible responses from publisher's site:
   – Item held/not held
   – If held, user has rights/no rights/available for fee
• Modest implementation cost for service providers
• Three publishers have implemented REM
 Balsa & commercial OpenURL
• Balsa is intended to operate as a subscription-free
  service for UK H&FE
• Minimal institutional configuration
• Lightweight solution for all institutions in UK
  H&FE (not dedicated to a specific institution)
• Commercial products provide a more
  comprehensive solution, at a price, and with an
  ongoing maintenance cost
    New problem for referring
     services: which broker?
• How does the referring service know the
  address of the broker for this user (the
  appropriate broker problem)?
• Various ad hoc methods proposed
• Typically achieved by configuration
• However this gives an R* I scaling problem
  – For referring services
  – For institutions
              Scaling issue
• Referrers               Institutions
      National OpenURL router
• All referring services use a single base URL:
• All institutions register the address of their
  OpenURL resolver with the national router
• The national router routes each OpenURL request
  to the appropriate resolver
• Reduces the cost to a discovery service of
  becoming OpenURL aware
• Reduces the cost to an institution of registering its
  OpenURL resolver with each referring service
              Router model
• Referrers                  Institutions

              Project details
• Project ends 31 December 2003
• Thereafter the aim is to make it available as
  a subscription-free service
• Available for evaluation now:
  – Access directly at
  – Or try via a referring service (Xgrain) at
          EDINA contacts
• Project manager:
  Sandy Shaw

• Technical manager
  Tim Stickland

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