Services on linked data

LD4L Workshop Breakout Session, Tuesday, February 24

facilitator: Jon Corson-Rikert

Risk of not knowing what to search for

  • Providing discovery endpoints
    • ‘hardened’ SPARQL endpoints may be less prone to down time – e.g., Fuseki documentation states that "authentication and control of the number of concurrent requests can be added using an Apache server"
  • publishing starting points with examples and standard extracts may help
    • emulate Social Explorer as a way to query the contents of a larger data source, in that case census data
    • the linked data fragments technology ( may facilitate hosting linked data without the server-side overhead and risk of a public SPARQL endpoint
  • VIVO/Vitro 'rich export' – augmenting standard linked data responses with standard queries
    • e.g., get all a person's publications from a single request rather than client having to issue multiple requests

Synchronizing harvested information

  • Risk of harvested or aggregated information going out of sync
    • Resource sync standard addressed the need to repeatedly synchronize and update
  • Semantic Web crawling leveraging HTML web crawler experience
    • what's attached
    • what has changed

Desire to be able to query on different axes


Reconciliation services

  • not necessarily centralized or monopolies
  • would work best in an iterative mode, with curation and provenance to manage difference of opinion (or evidence)
    • who's made that assertion – differentiate librarians from crowdsourcing
    • some way to express variable confidence levels
  • incorporate feedback from users
  • need protocols – could leverage a common API for reconciliation building on the OpenRefine API — specify as much metadata as you have, get ranked results back
  • surface (publish) the results – known servers, as with annotations – select which servers to request responses or harvest data from
    • notifications of new matches?
    • ability to +1 or thumbs-up the connection to corroborate – Reddit gets a lot of traction that way
    • repeating assertions in multiple repositories
  • but with other expressions for and levels of confidence in the relationship


  • RDF data shapes working group
  • DCMI tutorial on RDF validation
  • Measure the consistency of ontology use
  • Linked data needs mashup tools that test connections and illustrate bringing data together

Ontology extension mechanisms

Ability to push bookmarks

  • Small graphs of data, consumable by others, to a platform similar to Mendeley but not limited to bibliographic material
  • A service where I can push the results of my search, organized by topic
  • Add things to a collection I have 
  • Similar to an annotation service
  • You search, you refine it, you step back — now only save as bookmarks at one level
  • Nobody can use your web bookmarks now
  • Hide the URIs behind a UI

Additional ideas

  • Semantic autotagging
  • Nanopublications – breaking academic articles into independent assertions with a mechanism to agree/disagree
  • Side wikis – a plugin for the Netscape browser where a wiki could be associated with any web page and display additional, user-entered content or commentary on any web page
  • individual libraries will become the authorities for special collections — items, people, events
    • queries to a central area would find a match
    • cache the sameAs so don’t have to re-query; everybody who consumes has the cross-links
    • the sort of thing that OCLC might end up doing — could be any type of object — logical to start with works
  • regular expressions to apply against EAD to suggest what is linked to; feed into a system to validate, then give pointers to the link
  • a clustering algorithm to track the number of times a link between two entities is traversed, effectively shortening the distance between them
  • a better page rank algorithm for linked data
  • anybody a favorite semantic search engine (no – too siloed)
  • visualizations have to be crafted individually



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