Minutes: XDI TC Telecon Thursday 2011-08-11

[Drummond Reed <drummond.reed@xdi.org>]

Following are the minutes of the unofficial telecon of the XDI TC at:

Date:  Thursday, 11 August 2011 USA

Time:  1:00PM - 2:00PM Pacific Time (20:00-21:30 UTC)

ATTENDING

Mike Schwartz

Giovanni Bartolomeo

Drummond Reed

THE IDEARPAD LINK FOR TODAY IS:

     http://xdi.idearpad.org/39

1) LINK CONTRACT POLICY EVALUATION AND KYNETX RULES LANGUAGE (KRL)

Mike and Drummond reported on their call with Phil Windley, CTO of Kynetx. Drummond provided Phil's background as the former CIO of the State of Utah, the author of the O'Reilly book on Digital Identity, and the founder of Kynetx and develloper of the Kynetx Rules Language (KRL). Phil has been interested in XDI for a long time because he would like to see a standard API for Kynetx apps (which run in Javascript in the browser) to talk to a user's PDS (personal data store or personal data service).

Phil reviewed the policy evaluation logic at http://wiki.oasis-open.org/xdi/XdiPolicyExpression and found it very clear and compelling. So the balance of the discussion revolved around how link contracts can be used with KRL. We explored how this might be illustrated with a demo Kynetx app that works with both an XDI server (such as the OpenXDI server implementation) and with the KRL rules engine.

2) XDI AND RDF/OWL ONTOLOGY TOOLS

We discussed that some of Mike's customers are starting to ask when we expect to have the same ontology editors, viewers, validators, reasoners, and other tools for XDI that exist to RDF and OWL. Giovanni explained that:

• OWL provides a higher level ontology for RDF that builds on the RDF graph model.

• It has taken a number of years to define OWL (and now OWL 2.0) and build tools that use it, so it is likely to take a significant period to do the same for XDI.

• The XDI graph model has additional semantics that are not currently expressable in RDF and OWL.

Giovanni had a specific suggestion that he has brought up before but which now seems even more relevant: that we (or some other group) could write an OWL ontology that expresses in RDF the additional semantics of the XDI graph model. With that ontology we could solve two problems:

• We could write a spec for how to convert an XDI graph to an RDF graph (and back).

• Once converted, standard RDF/OWL ontology tools could be used to reason on the RDF graph.

Drummond said that he had made good progress on defining the rules for converting an RDF graph into an XDI graph, since the XDI graph model appears to be a superset of the RDF graph model. So when combined with Giovanni's suggestion it could all fit nicely into an XDI/RDF Transformation Spec that could define the rules for making the transformation in either direction.

There was a consensus that this is potentially a very powerful way to finally unite the worlds of RDF and XDI, however it also represents an unknown quantity of work, since none of us yet know how complex an OWL ontology would be needed to describe the semantics of the XDI graph model in RDF. And we are certain we'll need help with it.

We agreed that we should discuss it further with Bill and the rest of the TC members on the next call.

3) NEXT CALL

Since it is August vacation time and several TC members have travel, we decided to set the next call for Thursday September 8 at the regular time.

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ONGOING ISSUES LIST

Each of these is a candidate for the agenda for future calls.

* DO WE NEED SEPARATE METAGRAPH WORDS FOR EQUIVALENCE AND INVERSION? (added 2011-06-30 - Giovanni)

This is an open issue because algorithmic inversion does not have a direct corallary in RDF.

* SYNONYM HANDLING (added 2011-06-30 - Giovanni)

This remains an open issue because it raises challenges with compatibility with RDF.

* TRANSACTIONAL INTEGRITY FOR XDI (added 2011-03-24)

Since  versioning, as one example, involves multiple transactions that must be  commited as a group, we will need to address transactional integrity.  Specifically, we need to define how this will be handled at the protocol  level, vs. the implementation level.

* PROPOSED CONSTRUCTS/OPERATORS FOR XDI

Discuss the following wiki page originally posted by Giovanni:

  http://wiki.oasis-open.org/xdi/XdiNewFoundation

* DICTIONARY STRUCTURE

Mike would like an example of the PDX dictionary as soon as we can do it.

*   EQUIVALENCE SEMANTICS

Close on whether we need an additional $ word that is the equivalent

of Higgins Personal Data Model (PDM)  semantics of h:correlation,

which is not as strong as $is.

      http://lists.oasis-open.org/archives/xdi/201006/msg00036.html

* COOL URIS

Continue previous discussion about the use of standard RDF URIs in XDI:

  http://lists.oasis-open.org/archives/xdi/201006/msg00023.html