Tabulator recap

• Firefox extension (or online script)
• Allows graph of things and graph of documents to be browsed together
• Outline mode
• Query by example: subgraph template -> table of matching data
• Query results can have map, timeline, calendar views
• (October 2007 presenttaion on Tabulator then)

2007,8: Tabulator as editor

2007

• Editing in the outline (screencast)
• Modifying existing and adding new data
• Editing in the table mode *
• SPARQL-Update patch to server

2008

• Multiple panes in outline view
• Application-specific panes (FOAF, TAMI)
• ...

Where to store the data?

• Edit one document graph at a time
  • Not WYWIWYG - user browses integrated graph
  • Boring.
• Edit global smushed graph

  Need to figure out where to store data:

  • Update any data cell from its source
  • Add similar cells to same source
  • Add data to anything with one URI in a writeable URI
• Always affect a given graph
  • Needs UI to select target graph
  • Can't modify other graphs, only add
  • Needed for note-taking, annotation
  • (Not currently supported)

Editing via SPARQLUpdate

Write every change back to server

• HTTP header MS-Author-Via: SPARQL [sic]
• SPARQL langauge extended to allow update
  • INSERT ... DELETE ... WHERE
• SPARQL Update message POSTED to document URI
• Server reads doc, modified, writes back (in our case)
• Roll-back on User Interface if edit fails (clash, net error)
• Goal: Never lose user work
• Supported by DIG's data wiki and Begee's ARC2

Server side

• Public wiki available Wiki
• E.g: Open Data Projects
• Algae SPARQL Update engine
• Files read & written every change

Editing via WebDav

• HTTP header MS-Author-Via: DAV
• Client makes change to the graph
• Client re-serialized the graph
• Slower, obviously than sending SPARQL updates
• Issue: Editing graph after inference

Constraining user input

• Choosing predicates and objects
• User is given auto-complete box full of labels of things
• Ideally: RDFS + owl:disjointWith *
• Realistically, not much owl:disjointWith out there
• Please use rdfs:domain & range, not owl:Restriction
• Must be fast

Awareness of source document

• UI Conflict between GGG and WWW metaphors
• Reading: Trust, license, appropriate use*
• Writing: Access policy, license, use policy
• Tabulator: View Data Sources
  • Click on fact to find provenance
  • Click on provenance to get metadata, licensing
  • User-configurable coloring by license
• Area of much more work!

Future work

What about Forms?

• E.g. Fresnel language ('lenses')
• Too inflexible?
• Use forms as tips? Merge forms? Auto-extend forms?
• Generate forms automatcially, let user edit and name

State machines - User-configured workflow?

• E.g Bug tracker, W3C document process, joining a group, voting, etc
• Ontology for state diagram
• Pre-requisites on trnsition
• Form of info to be provided for transition
• Append-only store

Collaborative shared editing

• Goal: When I change something you are looking at, your view changes
• (eg Collabrative editors, Lee Feigenbaum's demo while at IBM, etc)
• Built into widget library?
• Protocol design issues: Reverse HTTP? Hanging HTTP? UDP?
• Peer-peer distribution

Summary: Interesting questions

• Where to store data?
• How to know what properties to propose
• How to know what objects to propose
• Let the user understand the destination of contributions (provenance reversed)
• Forms?
• Workflow in a publishing space?
• User-created systems

Thank you

Random links

Tabulator demo (Firefox, See help.):

Tabulator view links:

• W3C org and docs
• [Restricted] W3C team database.
• [Restricted] Timezones [restricted]

See also:

• Tabulator Help
• Berners-Lee et. al., "Tabulator: Exploring and Analyzing linked data on the Semantic Web" The 3rd International Semantic Web User Interaction Workshop Athens Georgia, November 2006

More Information

• Previous presentation on tabulator (October 2007): http://dig.csail.mit.edu/2007/Talks/1001-tab-tbl/
• This presentation (April 2008): http://dig.csail.mit.edu/2008/Talks/0422-tab-tbl/

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