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Re: Comments of PROV-DM document (Section 2.1 and 3)

From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
Date: Mon, 10 Oct 2011 17:18:58 +0100
Message-ID: <EMEW3|3dfc57def44a308302368ac732c9d701n99HJ108L.Moreau|ecs.soton.ac.uk|4E931AF2.9070400@ecs.soton.ac.uk>
To: Satya Sahoo <satya.sahoo@case.edu>
CC: Provenance Working Group WG <public-prov-wg@w3.org>, Paolo Missier <Paolo.Missier@ncl.ac.uk>
Hi Satya,

Thanks for your comments. Some responses interleaved with your
comments.

Luc

 > Hi all,
 > I have some review comments on Section 2.1 and Section 3 of the
 > current version of the conceptual document (these do not include
 > typos/language and related issues).
 >
 > Section 2.1 ===== 1. A characterized thing fixes some aspects of a
 > thing and its situation in the world, so that it becomes possible to
 > express its provenance, and what causes these specific aspects to be
 > as such. An alternative characterized thing may fix other aspects, and
 > its provenance may be entirely different.
 >
 > Issue: A "thing" may be characterized differently, that is viewed in
 > distinct ways, but they are still the same thing. Does the above
 > statement refer to the "same" thing characterized differently or
 > distinct things? If the above statement is referring to different
 > characterization of the same thing, how can their provenance be
 > "entirely different"?

The example in section 2.1 illustrates multiple perspectives about a same
resource with a URL. The provenance is different.

Removed word 'entirely'.

 >
 > 2. The provenance of these three characterized things will differ, and
 > may be along the follow lines: a) the provenance of a report available
 > at URL may include: the act of publishing it and making it available
 > at a given location, possibly under some license and access control;
 > b) the provenance of the version of the report available there today
 > may include: the authorship of the specific content, and reference to
 > imported content; c) the provenance of the report independent of where
 > it is hosted over time may include: the motivation for writing the
 > report, the overall methodology for producing it, and the broad team
 > involved in it.
 >
 > Issue: Not sure about the issue that is being illustrated/described
 > here - the three "characterized" things may be the same or
 > different. In case they are the same thing - Report A (version 1.0,
 > only one version was ever published) located at URL
 > www.xyz.com/ReportA_V1.0 can be referred to differently by individual
 > applications according to their requirements: simply as Report A, or
 > as version 1.0 of Report A, or www.xyz.com/ReportA_v1.0 - in this case
 > provenance of the three different characterization will be same.

The point is not that a same thing is referred to differently by
applications. It is that we take different perspectives on it.
An egg vs a set of molecules.

 > Further, we can associate the provenance information for (b) with (a)
 > also, for example reference to imported content? Similarly for (c) and
 > (b), (a), for example the motivation to write the report or broad team
 > involved. I am confused regarding the criteria used to state the
 > particular provenance information can be associated with (a), (b), or
 > (c).

I don't understand this point.


 > In case they are referring to different things (different reports
 > located at same URL, different version of same report etc.), the
 > provenance will be different.

But that's not the same, we refer to the same report.

 >
 > 3. This specification assumes that a partial order exists between
 > events.
 >
 > Issue: Are we excluding overlapping events or events that are
 > "contained" in other events?

Events are instantaneous. Hence, there is no overlap and
containment. Two events occurs at the same instant or not.

 >
 > 4. In our conceptualization of the world, punctual events, or events
 > for short, happen in the world, which mark changes in the world, in
 > its activities, and in its things.
 >
 > Issue: This definition of event seems to be a specialization of a PE?
 > What are the distinguishing features (if any) of an event vis-a-vis
 > PE?

I don't see why they seem to be a specialization. Is it because event 
duration=0?
We have four types of events, two of which are start and end of PE.
So, to me they are very distinct from PE.

 >
 > Section 3 ===== 1. The wasComplementOf relationship is used to denote
 > that two entities complement each other, in the sense that they each
 > represent a partial, but mutually compatible characterization of the
 > same thing.
 >
 > Issue: What does "entity" in the above statement refer to? How can two
 > entities refer to the same thing - assuming that entity is the term we
 > agreed to use for "thing"?

Entity is introduced in previous sentence.
An entity (expression here!) does not refer to a thing, but represents a 
characterized thing.

Entity is not defined here as thing (in this version of the document).

 >
 > 2. Qualifiers can be associated to relations, namely use and
 > wasGeneratedBy, in order to further characterise their nature. Role is
 > a standard qualifier.
 >
 > Issue: Are qualifiers associated with relations only - they can be
 > associated with entities also to further "characterize" it (and
 > thereby create specialized entities)? What do we mean by "standard
 > qualifier"?

Qualifiers are for relations.
Entities have attributes (characterizing them) (and also annotations)

standard replaced by pre-defined

 >
 > 2. Attributes, qualifiers, and annotation are the main extensibility
 > points in the model: individual interest groups are expected to extend
 > PROV-DM by introducing new sets of attributes, qualifiers, and
 > annotations as needed to address applications-specific provenance
 > modelling requirements.
 >
 > Issue: Since annotation have no prescribed meaning, how can they be
 > used to extend the model? What is the difference between attributes
 > and qualifiers? Qualifiers are standard mechanism for specialization
 > (either entities or relations) - new attributes may or may not be used
 > to define specialized entities or relations. For example, a new
 > attribute stating that a Toyota Corolla car hasMileage 100miles does
 > not necessarily extend the entity Toyota Corolla car?

Annotations: we have given example of use of annotation, where application
specific annotations give instructions on how to render provenance.

Attributes are for entities and PEs
Qualifiers are for relations

There is no concept of "specialized entity" in the model. What do you mean?
Entity expressions can be complement of other entity expressions


 >
 > Thanks.
 >
 > Best, Satya
 >


On 09/26/2011 12:14 AM, Satya Sahoo wrote:
> Hi all,
> I have some review comments on Section 2.1 and Section 3 of the 
> current version of the conceptual document (these do not include 
> typos/language and related issues).
>
> Section 2.1
> =====
> 1. A characterized thing fixes some aspects of a thing and its 
> situation in the world, so that it becomes possible to express its 
> provenance, and what causes these specific aspects to be as such. An 
> alternative characterized thing may fix other aspects, and its 
> provenance may be entirely different.
>
> *Issue*: A "thing" may be characterized differently, that is viewed in 
> distinct ways, but they are still the same thing. Does the above 
> statement refer to the "same" thing characterized differently or 
> distinct things? If the above statement is referring to different 
> characterization of the same thing, how can their provenance be 
> "entirely different"?
>
> 2. The provenance of these three characterized things will differ, and 
> may be along the follow lines:
> a) the provenance of a report available at URL may include: the act of 
> publishing it and making it available at a given location, possibly 
> under some license and access control;
> b) the provenance of the version of the report available there today 
> may include: the authorship of the specific content, and reference to 
> imported content;
> c) the provenance of the report independent of where it is hosted over 
> time may include: the motivation for writing the report, the overall 
> methodology for producing it, and the broad team involved in it.
>
> *Issue*: Not sure about the issue that is being illustrated/described 
> here - the three "characterized" things may be the same or different. 
> In case they are the same thing - Report A (version 1.0, only one 
> version was ever published) located at URL www.xyz.com/ReportA_V1.0 
> <http://www.xyz.com/ReportA_V1.0> can be referred to differently by 
> individual applications according to their requirements: simply as 
> Report A, or as version 1.0 of Report A, or www.xyz.com/ReportA_v1.0 
> <http://www.xyz.com/ReportA_v1.0> - in this case provenance of the 
> three different characterization will be same.
>
> Further, we can associate the provenance information for (b) with (a) 
> also, for example reference to imported content? Similarly for (c) and 
> (b), (a), for example the motivation to write the report or broad team 
> involved. I am confused regarding the criteria used to state the 
> particular provenance information can be associated with (a), (b), or (c).
>
> In case they are referring to different things (different reports 
> located at same URL, different version of same report etc.), the 
> provenance will be different.
>
> 3. This specification assumes that a partial order exists between events.
>
> *Issue*: Are we excluding overlapping events or events that are 
> "contained" in other events?
>
> 4. In our conceptualization of the world, punctual events, or events 
> for short, happen in the world, which mark changes in the world, in 
> its activities, and in its things.
>
> *Issue*: This definition of event seems to be a specialization of a 
> PE? What are the distinguishing features (if any) of an event 
> vis-a-vis PE?
>
> *Section 3*
> =====
> 1. The wasComplementOf relationship is used to denote that two 
> entities complement each other, in the sense that they each represent 
> a partial, but mutually compatible characterization of the same thing.
>
> *Issue*: What does "entity" in the above statement refer to? How can 
> two entities refer to the same thing - assuming that entity is the 
> term we agreed to use for "thing"?
>
> 2. Qualifiers can be associated to relations, namely use and 
> wasGeneratedBy, in order to further characterise their nature. Role is 
> a standard qualifier.
>
> *Issue*: Are qualifiers associated with relations only - they can be 
> associated with entities also to further "characterize" it (and 
> thereby create specialized entities)? What do we mean by "standard 
> qualifier"?
>
> 2. Attributes, qualifiers, and annotation are the main extensibility 
> points in the model: individual interest groups are expected to extend 
> PROV-DM by introducing new sets of attributes, qualifiers, and 
> annotations as needed to address applications-specific provenance 
> modelling requirements.
>
> *Issue*: Since annotation have no prescribed meaning, how can they be 
> used to extend the model? What is the difference between attributes 
> and qualifiers? Qualifiers are standard mechanism for specialization 
> (either entities or relations) - new attributes may or may not be used 
> to define specialized entities or relations. For example, a new 
> attribute stating that a Toyota Corolla car hasMileage 100miles does 
> not necessarily extend the entity Toyota Corolla car?
>
> Thanks.
>
> Best,
> Satya

-- 
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 Monday, 10 October 2011 16:19:48 GMT

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