Rough Minutes of the Open ODRL WG Meeting

These are the rough minutes of the ODRL WG meeting at the 2007 Virtual Goods Workshop in Koblenz, Germany. I hope it is complete, but I could have unintentionally left out things ... they are reconstructed from notes I typed at the meeting.

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There hasn’t been a face to face ODRL meeting since the last International ODRL workshop in Lisbon in 2005. With ODRL joining forces with the Virtual Goods workshop, the conference also provided an opportunity to have a face to face meeting of the ODRL v2 working group. Three regular contributors from the mailing list were at the meeting: the co-leaders Dr Renato Iannella and Dr Susanne Guth and myself. However, since it is an open meeting, a number of other interested parties were also present, which provided the discussions with some new positions and insights. The other attendees included (and this is not the complete list) Pramod Jamkhedkar (PhD student from the University of New Mexico), GR Gangadharan (PhD student from the University of Trento), Martin Springer (independent contributor to the DMP) and Dr Rüdiger Grimm (from our hosts at the University of Koblenz-Landau).

The main thrust of the meeting was a push to simplify the ODRL v2 model, in an attempt to create a simpler core language; which could then be extended to have different profiles such as licensing and negotiation support. Susanne Guth and I promoted the use of access control as the base model for v2. Pramod Jamkhedkar however promoted the use of database style definition, and maybe the use of tupple calculus and a sound logical (mathematical) structure. In the paper I am due to present at the ACM DRM Workshop in two weeks time, I do present something that bridges these two approaches, and could lay the foundation for the v2 model. I will release a link to the paper on the WG mailing list after I present the paper in Washington in 2 weeks time.

Martin Springer raised the point that a model depends on what we need to describe, and that requires detailed use cases. Susanne Guth countered that detailed use cases would however lead to very specific models, which would not achieve the generality required for ODRL. In this respect, the current approach of stating general requirements (or goals) for the model is much better than specific use cases.

Rüdiger Grimm raised the question on the necessity of the duties element. After all, duties could be reworded as constraints. Pramod Jamkhedkar commented that, everything could be modelled as rights and constraints – and the use of duties and parties are dependent on the level of abstraction we want. It was felt that duties provide an additional level of expressiveness and thus should be retained.

Susanne Guth raised the issue of a container. The container, as defined in ODRL 1 was too complex, and needed to be refined. Susanne proposed a narrower definition of the container, as defined in the current model document. She also suggested the use of XLink for the XML implementation of the concept.

Renato Iannella raised the issue of whether the exclusive attribute needs to be retained. It is a rarely used concept, and I commented that it could easily be expressed as a duty instead of an attribute. It was agreed that this may be the best approach, and an example on how it can be used can be discussed in the model.

Also with duties, the non-performed section was removed, as it can also be expressed as another separate duty. This approach could also have less processing requirements than the current approach of a non-performed section.

In the discussion of the Assets element, it was decided to remove WEMI and metadata. Parts, which aimed to define collections of assets is strictly not necessary, and was thus removed. The inheritance model however needs to be revisited – OMA uses the inheritance model, but it does not strictly belong under the Asset element. Any changes to the inheritance model, would require some clarifications from OMA.

reType, which I introduced to simplify the agreement/offer model was retained. It offers a high degree of flexibility and it was decided that the vocabulary for reType will not be defined (apart from agreement probably).

The tradable attribute was removed, as negotiation support will be a profile and not a core component of the model.

The following elements were removed: signature, encryption, legal and communication.