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Re: Linking Across Provenance Bundles - comments

From: Luc Moreau <l.moreau@ecs.soton.ac.uk>
Date: Fri, 30 Nov 2012 17:30:12 +0000
Message-ID: <EMEW3|bbc9af094331e8b349d8948a7f1571b5oAYHUG08l.moreau|ecs.soton.ac.uk|50B8ED24.9080401@ecs.soton.ac.uk>
To: Graham Klyne <GK@ninebynine.org>, W3C provenance WG <public-prov-wg@w3.org>
Hi Graham, all,

The staged document can be found at:
http://dvcs.w3.org/hg/prov/raw-file/default/links/releases/WD-prov-links-20121211/Overview.html

Let me know if you find any bug.

I have added links to the dm/constraints sections that use the term 
'aspect' and I have also
added its informalmeaning.

I didn't understand the conflict you suggested. Can you clarify?

Finally, the notions of observer, perspective, context are a very 
significant departure from what
we currently have, and the dm in general.  I don't feel comfortable with 
them in the document.

Luc

On 11/29/2012 06:15 PM, Graham Klyne wrote:
> http://dvcs.w3.org/hg/prov/raw-file/default/links/prov-links.html
>
> My comments are focused on Section 2, Conceptual Definition of Mention
>
> [[
> An entity e1 may be mentioned in a bundle b, which contains some 
> descriptions about this entity e1: how e1 was generated and used, 
> which activities e1 is involved with, the agents e1 is attributed to, 
> etc. Other bundles may contain other descriptions about the same 
> entity e1. Some applications may want to augment the descriptions of 
> entity e1 found in bundle b with other information. To this end, PROV 
> allows a new entity e2 to be created and defined as a specialization 
> of the preceding entity e1, and which presents at least an additional 
> aspect: the bundle b containing some descriptions of e1. With this 
> relation, applications that process e2 can know that the attributes of 
> e2 may have been computed according to the descriptions of e1 in b.
> ]]
>
> "Some applications may want to augment the descriptions of entity e1 
> found in bundle b with other information" appears to be in conflict 
> with the earlier statement "Other bundles may contain other 
> descriptions about the *same* entity" (my emphasis).
>
> [[
> The mention ◊ of an entity in a bundle (containing a description of 
> this entity) is another entity that is a specialization of the former 
> and that presents the bundle as a further additional aspect.
>
> An entity is interpreted with respect to a bundle's description in a 
> domain specific manner. The mention of this entity with respect to 
> this bundle offers the opportunity to specialize it according to some 
> domain-specific interpretation.
> A mention of an entity in a bundle results in a specialization of this 
> entity with extra fixed aspects, including the bundle that it is 
> described in.
> ]]
>
> I have two concerns here:
>
> This definition leans heavily on the notion of "fixed aspects", but 
> this term is not actually defined anywhere.
>
> Philosophically, I have difficulties with the implication that simply 
> by being mentioned in a bundle somehow changes the entity itself.  
> Suppose you are looking at an elephant, and writing down a description 
> of that elephant.  Then I come along and look at the elephant from a 
> different perspective, and write down a description of what I see.  We 
> may put down different descriptions, but we are describing the *same* 
> elephant. The fact of me doing that doesn't change the elephant in any 
> way, nor does it affect the validity of your description concerning 
> the elephant.  Yet the idea that an observation is a new "fixed 
> aspect" seems to suggest that this is act of observation makes it a 
> different elephant.  (Not allowing Heisenberg/observer effects here.)
>
> What I think is missing from your description is some notion of the 
> perspective ("observation context") from which the descriptions in a 
> bundle are derived.
>
> So here's my attempt to try and capture something of this:
>
> [[
> Statements about an entity are based on information available from 
> some perspective, and the extent of information available may be 
> affected by the context of an observer that records it.  The mention 
> construct provides a way to make additional statements about the 
> entity from the same context or perspective as other statements in a 
> bundle.  For example, one bundle may contain statements about a web 
> page accessed from a network connection in USA which is presented 
> containing comments authored by Americans, and another may contain 
> statements about the same page accessed at the same time from China, 
> which may contain a different set of comments.  Deducible provenance 
> about the contributors to this page may thus vary based on where it is 
> accessed from.
>
> The mention construct provides a way to associate this additional 
> contextual information with an entity, such as the location from which 
> it has been accessed when making some provenance assertions.
> ]]
>
> #g
> -- 
>
>

-- 
Professor Luc Moreau
Electronics and Computer Science   tel:   +44 23 8059 4487
University of Southampton          fax:   +44 23 8059 2865
Southampton SO17 1BJ               email: l.moreau@ecs.soton.ac.uk
United Kingdom                     http://www.ecs.soton.ac.uk/~lavm
Received on Friday, 30 November 2012 17:30:56 GMT

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