Applied Linked Data 2016-12-13

• sanderson (BPL)
• zschoenb
• Lynette Rayle (Cornell)
• Anna Headley (CHF)
• Huda Khan (Cornell)

1. Lynette's update of caching configuration, based on Marmotta's config

   1. Settings in Marmotta web based config for what is available there:

      1. enabled

      2. connection_timeout

      3. data timeout

      4. expiry (default 1 day)

      5. min expiration

      6. if site provides expiration it uses that.

      7. if not it looks for an endpoint

      8. allows you to set a couple of configuration values (expected format, mime type, and cache expiration) on a per-endoint basis

      9. register one with a unique name and tell it what it returns

      10. including a prefix would allow you in some cases to have a per-subauthority cache expiration

      11. you can set a specific expiration just for this endpoint (otherwise it uses the default expiration

   2. Lynette shows us a config class for LinkedDataFragments based on the marmotta config

      1. Lynette will push her work by Thursday so Steven can start on the Blazegraph side.
          
2. Resolving string literals in Linked Data Fragments
   
   1. Getting to string literals can be complex and require the resolution of uris. IE. Can't just search for "prefLabel" or "label" on the data. Could take multiple SPARQL queries to do a good matching literal search if the main object has pointers to objects that then contain its various label.
      1. Example in etherpad related to how MESH is structured. 
         1. Only the prefTerm (like "Myocardial Infarction") is on the main object. To get to alternative terms like "Heart Attack" that a user might search, need to resolve two levels of uri's on that object.
            
            
   2. Discussion indicates that the best place for this type of query functionality is Questioning Authority. It would need to have a configuration that made it aware of Linked Data Fragments. This work has been started in:
      
      1. Questioning Authority fork - https://github.com/ld4l-labs/questioning_authority/tree/linked_data  work for LD4L-Labs to access linked data authorities via QA
      2. README doc:  https://github.com/ld4l-labs/questioning_authority/tree/linked_data#linked-open-data-lod-authorities
          
   3. Linked Data Fragments would need a SPARQL passthrough interface to support queries from Questioning Authority. 
      1. This moves the codebase away from the original spec but no better approach was thought up.
          
3. Feedback from Metadata IG about changing to an IG outside of their umbrella?
   1.  The Metadata Interest Group was fine with this move.
      1. They still had an interest in us attending the monthly meetings there to provide updates from this group's work however.

Next Meeting:  January 10 at 10pst/1est