[provenance-challenge] Re: clarifying queries

[Joe Futrelle]

OPM is intended to be annotated, since it's scoped to just represent the causal relationships. My position is that rather than creeping the scope of OPM beyond causal relationships we need some agreement on how to attach annotations to OPM graphs in various representations. We sorta get that for free in RDF since RDF is already a graph structure where any node can be annotated with terms from any ontology; in XML and SQL we face more choices about how to do it, but fortunately I don't think any of them are very difficult or controversial.

--
Joe Futrelle
Cyberenvironments and Technologies
National Center for Supercomputing Applications
http://www.ncsa.uiuc.edu/People/futrelle

----- "Paolo Missier" <pmissier at cs.man.ac.uk> wrote:

> Paul,
> > I think this is a problem that we should definitely take up, are
> there 
> > ways to commonly refer to values...? I mean right now it's hard to 
> > determine what content is available in the value field of each 
> > artifact, hence, your suggestion of using annotations. Does
> something 
> > like this need to be part of OPM.
> I think the issue of representing (references to) values has come up 
> quite clearly throughout the challenge, with proposals such as using
> the 
> value field to keep refs to values (URIs), and then annotating the OPM
> 
> graph with references to services that are able to de-reference those
> URIs.
> 
> At the same time, I reckon adding annotations to causal graphs will 
> become inevitable at some point -- and these have the advantage over 
> actual values of being generally well-bounded in size, so I suggest we
> 
> address this during the meeting so it is done in a principled way.
> 
> Regards, -Paolo