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Re: A proposed provenance wg draft charter

From: Olaf Hartig <hartig@informatik.hu-berlin.de>
Date: Sat, 23 Oct 2010 23:58:54 +0200
To: public-xg-prov@w3.org
Message-Id: <201010232358.57194.hartig@informatik.hu-berlin.de>
Hello,

I would support a W3C provenance WG. Thanks Paul and Luc for putting together 
the draft charter. However, I have some comments and questions regarding the 
draft:

1.) Regarding Sec.2, third bullet point "Specify how to embed provenance in 
document with RDFa ..." and regarding point (1) in Deliverable D4:
 * Why is this only about embedding provenance in HTML documents? Provenance 
of data retrieved from the Web (e.g. from a Linked Data URI look-up interface, 
or from a SPARQL endpoint) is equally important I would say.
 * Embedding provenance descriptions using RDFa is not a big deal, once one 
agreed on the vocabulary to be used for the representation of provenance 
information. The only issue is associating the provenance description with the 
specific HTML document it is embedded in. This cannot be done by making 
statements that have as subject the URL from which the document was accessed. 
This URL refers to the Web resource in general but not to the specific 
representation serialized in the specific HTML document retrieved at a specific 
point in time. BTW, the same issue exists for RDF graphs that can be retrieved 
by looking up URI via a Linked Data URI look-up interface.

2.) Regarding Deliverable D4: What does "(3) how to query provenance through a 
SPARQL endpoint" mean? What do you have in mind here?

3.) Regarding Sec. 2.2 Out of Scope - Why is database provenance out of scope? 
This charter focus on provenance of things on the Web as far as I understand. 
I think the W3C's understanding of (the future of) the Web is a Web of 
documents _and_ data. This includes SPARQL query services (aka endpoints) as 
an important way to provide access to data on the Web. Hence, the provenance 
of SPARQL result sets retrieved from the Web is one of the things that should 
be addressed by a W3C provenance WG; this provenance includes provenance of 
each single result in the result set. The work by Irini and colleagues is an 
important first step here. The question of SPARQL result set provenance becomes 
even more important when we consider the integration of a simple query 
federation approach (i.e. the new SERVICE clause) in the upcoming new version 
of the query language or when we think about alternative query execution 
approaches that answer queries over data from multiple sources (e.g. my link 
traversal based query execution approach).

4.) Regarding Sec.2 "The Working group will keep this two-pronged approach for 
the mapping to RDF: a simple vocabulary allowing provenance to be asserted 
easily, and an ontology that extends the vocabulary with permitted inference." 
- Why? I'm not familiar with the OPM ontology and what it provides in addition 
to OPMV, but why shouldn't it be possible to satisfy both requirements (ease 
of asserting provenance and permitting inferences) with a single vocabulary?
I would say that it requires at least some investigation whether an easy to 
use vocabulary can or can not provide for all kinds of inferencing possible 
with OWL. For instance, our Provenance Vocabulary provides support for 
inferring additional statements using some of the constructs available in 
OWL2.

Greetings,
Olaf


On Friday 15 October 2010 13:58:35 Paul Groth wrote:
> Hi All,
> 
> Today on the call we are scheduled to talk about preparations for the
> final report. Luc and I feel that to write a compelling final report we
> should be clear about exactly what the report should recommend. There
> has been some consensus that a working group should be formed around the
> recommendations extracted from the scenarios (
> http://www.w3.org/2005/Incubator/prov/wiki/Recommendations_for_scenarios).
> 
> To that end, we have prepared a draft working group charter (
> http://users.ecs.soton.ac.uk/lavm/draft-charter.html ). We note this is
> only *our own* proposal and we see this as a starting point for
> discussion within the group.
> 
> We look forward to any comments, questions, thoughts about this
> proposal. We hope this helps the group to continue to coalesce around a
> way forward.
> 
> Thanks,
> Paul and Luc
Received on Saturday, 23 October 2010 21:59:34 GMT

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