W3C home > Mailing lists > Public > public-prov-wg@w3.org > December 2011

Re: Detailed fedback on PROV-DM document

From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
Date: Fri, 16 Dec 2011 12:42:36 +0000
Message-ID: <EMEW3|9f54ec621e8d4714d3199373de87b60fnBFCge08L.Moreau|ecs.soton.ac.uk|4EEB3CBC.1080307@ecs.soton.ac.uk>
To: public-prov-wg@w3.org
Hi Yolanda,

Thanks for your very constructive input.
I have made a number of edits.
I hope they address some of your questions.

To see the exact edits, you can look at the diffs:

They include a detailed response to your comments.

Some comments have not been addressed because they involve broader 
planned changes (on account),
or are being currently debated (notion of responsibility/agent)

Best regards,

On 12/08/2011 03:44 PM, Yolanda Gil wrote:
> All,
> I went over the PROV-DM and the PROV-O documents, and have some comments.
> My first comment is that overall the documents read reasonably well, 
> orders of magnitude better than the version that was released a couple 
> of months ago.
> I have some suggestions, a few that could be easily and immediately 
> done, others that should probably wait for the next round of 
> revisions.  Some easy edits that I think would improve the readability 
> of the document.  Others may seem to me like easy edits but perhaps 
> you think deserve further discussion, I could not easily discern this 
> for some of the items.
> My comments:
> 1) Section 2.1.1: The sentence "In the world, activities involve 
> entities in multiple ways: they consume them, they process them, they 
> transform them, they modify them, they change them, they relocate 
> them, they use them, they generate them, they are controlled by them, 
> etc." could be improved by stating it as: "In the world, activities 
> involve entities in multiple ways: consuming them, processing them, 
> transforming them, modifying them, changing them, relocating them, 
> using them, generating them, being controlled by them, etc.
> 2) Section 2.1.1: I'd add a sentence at the end of the description of 
> agent to say why it is considered a subclass of entity, something like 
> "PROV-DM considers agents as a type of entity so that the model can be 
> used to represent the provenance of the agents themselves.  For 
> example, a spellchecker software may be an agent of a document 
> preparation activity, but itself can have a provenance record that 
> states who its vendor is."
> 3) At the beginning of section 3, the notion of a "record" is 
> introduced.  I get an idea of what is meant by record, but I don't 
> think it is well motivated.  OWL does not have "records" but it can be 
> used to state assertions about classes and objects, so why do we need 
> this notion of record.  Also, what is there raises several questions 
> that may or may not have the following answers: "A provenance record 
> is composed of a set of entity records, a set of activity records, a 
> set of agent records, a set of generation records, (and so on).  An 
> entity record is a type of provenance record (and so are the others).  
> A provenance record can have in turn its own provenance record, where 
> it would be considered an entity."
> 4) Section 4.1: It took me a couple of backs and forths to realize 
> that e0 is a type while e1...e6 are instances.  I'd suggest to rename 
> e0 to be crime-file, or cf, or something like that.
> 5) Section 4.2: The examples of Activity Records I think would be more 
> clear if they had "edit" instead of "add-crime-in-London" and "edit" 
> instead of "edit-London-New-York".
> 6) Section 4.2: In the examples of Generation Records, I did not 
> understand g1 and g2 at all.
> 7) Section 5.1:  The terms "account", "production", and "record 
> container" pop up out of nowhere.  They should be introduced and 
> motivated a bit.  They should also be related to the notion of 
> "record" better than they are now, this is not very clear.  I suspect 
> there might be plans to discuss this aspect of the model further in 
> the WG.
> 8) Section 5.2.1: I would change the sentence "If an asserter wishes 
> to characterize an entity with the same attribute-value pairs over 
> several intervals, then they are required to assert multiple entity 
> records, each with its own identifier (so as to allow potential 
> dependencies between the various entity records to be expressed)." to 
> clarify the asserting so it says something like: "If an asserter 
> wishes to characterize an entity with the same attribute-value pairs 
> over several intervals, then they are required to directly assert or 
> create axioms to infer assertions for multiple entity records, each 
> with its own identifier (so as to allow potential dependencies between 
> the various entity records to be expressed).".
> 9) Section 5.2.3: The examples of agents could include a spellchecker 
> agent, just to show a bit of diversity in what we consider to be agents.
> 10) Section 5.2.4: The example of the note record should show a link 
> to some provenance record, ideally one that would have been shown as 
> an example in section 5.1 (maybe the g1 and g2 that I mentioned in 
> point 5 above).
> 11) Section 5.3.3: We argue that we don't want to get into 
> "responsibility".  But we introduce the term "responsible" and 
> "subordinate".  I suggest we refer to them as "represented-agent" and 
> "representing-agent" instead.  Also, the section is titled 
> "Responsibility Record", so that will be confusing, maybe "Delegation 
> Record" would be better.
> 12) Section 5.3.3:  The example uses the terms "delegation" and 
> "contract".  Perhaps useful to mention that these are domain terms to 
> make clear that they are not part of the model.
> 13) Section The sentence "To promote take-up, PROV-DM offers 
> a mild version of responsibility in the form of a relation to 
> represent when an agent acted on another agent's behalf." is a bit of 
> an awkard way to introduce this, so I'd replace it by "The definition 
> of agent mentions that an agent is a type of entity that can be 
> assigned some degree of responsibility for an activity.  In many 
> situations, the creators of a provenance record may not have the 
> authority to ascribe responsibility to the various agents that they 
> know are involved in the activity.  For example, the developer of a 
> provenance service using PROV-DM could say that a student and his 
> advisor were both involved in creating a dataset, but might not be in 
> a position to know who has actual responsibility for the dataset.  
> Responsibility often has legal connotations that could deter 
> developers and users of PROV-DM from stating responsibility assertions 
> in provenance records.  To address this, PROV-DM offers a mild version 
> of responsibility in the form of a relation to represent when an agent 
> acted on another agent's behalf.".
> 14) Section The terms "we introduce a PROV-DM reserved 
> attribute STEPS" is used for the first time, no idea what that means.  
> Maybe just say "we introduce a PROV-DM attribute STEPS".  More 
> importantly, I did not understand what steps means.
> 15) Section  Complementarity is very confusing, even its 
> description in the primer was confusing to me.  And I am a planning 
> person used to thinking about entities changing, states, fluents, etc 
> etc.  I even wrote a survey on "Planning and Description Logics" a 
> while back.  But this is actually a very complex area that I don't 
> think is well understood at all.  For my money, I would say this is 
> worth a side chat with Pat Hayes about this particular aspect of the 
> model, to get his guidance.  He originally worked with McCarthy on the 
> frame problem and understands very well all the different issues 
> involved in this type of logic to reason about actions and change.
> 16) Section 5.4.1:  Could use a bit of introduction to introduce why 
> separate provenance records may be created.  For example, in emailing 
> a file there could be a provenance record kept by the mail client, 
> another by the SMPT server, etc.  It would also be useful to give 
> motivating scenarios/examples for how accounts can be nested.
> 17) Section 5.4.1: The example that introduces account acc2 says at 
> the end that the result of the merge violates generation-unicity.  But 
> if I am following this correctly, if a1 and a0 are asserted to be the 
> same then there is no violation.  Perhaps worth clarifying this, or 
> perhaps finding a more real-world example that really really creates a 
> violation.  Otherwise people are going to be scared of merging 
> provenance records, which I think is the opposite of what we want.
> 18) Section 5.4.2: It states "A record container is not a record."  I 
> am puzzled.  This is related to the confusion I raised in point 6.
> 19) Section 6.2: I did not understand why the notion of "traceability 
> record", why is it introduced, and how is it different from a 
> "derivation record".
> 20) Section 6.5: The sentence "Attribution models the notion of an 
> activity generating an entity identified by e being controlled by an 
> agent ag, which takes responsibility for generating e." could be 
> perhaps replaced by "Attribution models the notion of an activity 
> generating an entity identified by e being controlled by an agent ag."
> 21) Section 6.7: I did not understand what a "summary record" is.  I 
> am guessing we want a notion that someone can excerpt some subset of 
> assertions from a provenance record in order to create a summary 
> record.  Is this right?  If so, why would this apply only for entities 
> and not for other parts of the model?  Also: why wouldn't we use 
> PROV-DM terms to express this meta-derivation?  It would make the 
> model easier if we did not need to add an extra notion of "summary 
> record" as here.  Or perhaps I did not understand.
> One more comment that I am pretty certain is more appropriate for 
> future discussions of the model:
> 22) Proposal for hadRoleIn:  This proposal is motivated by agent being 
> a subclass of entity.  Should there be a relation between entity and 
> activity that is subsumes (generalizes) used, generatedby, and 
> wasAssociatedWith?  I think such a relation would allow us to state 
> that an entity had to do with an activity but we don't yet know how 
> exactly it was involved in the activity (eg whether it was an agent, 
> or it was used by it, or generated by it, or...).  I would propose to 
> call this something like <entity hadARoleIn activity>.  We should 
> think about how this aligns with what we now call "roles" (my choice 
> of name for this new general relation is not a coincidence), so in the 
> examples in PROV-DM document section 5.2.3 instead of 
> "[prov:role="sponsor"]" perhaps we could see sponsorOf as a 
> specialization of hadRoleIn and of wasAssociatedWith.
> On a rather pedantic note, maybe "New-York" should be "New York", and 
> that perhaps "half-hexagonal shape" should be "pentagon shape".
> Sorry for the long email...
> Best,
> Yolanda
> Yolanda Gil, USC/ISI
> +1-310-448-8794

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, 16 December 2011 12:45:42 UTC

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