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Re: PROV-ISSUE-331: feedback on PROV-Dm WD5

From: Graham Klyne <Graham.Klyne@zoo.ox.ac.uk>
Date: Sat, 07 Apr 2012 08:20:07 +0100
Message-ID: <4F7FEAA7.3020205@zoo.ox.ac.uk>
To: Paul Groth <p.t.groth@vu.nl>
CC: W3C provenance WG <public-prov-wg@w3.org>
Paul,

Yes, it's largely a document/text quality thing - I feel it doesn't entirely lay 
things out clearly enough for its target audience, and in some cases is actively 
confusing.  This may be "editorial", but I think it's important enough to need 
addressing to move forwards towards LC.  There are a few points of substance 
(mainly stuff that feels superfluous to me), but I wouldn't be surprised to be 
lone voice on that.

I've indicated a number of specific points points in the "details" part of my 
email, with suggested alternative phrasing, though there are many more (similar 
to those I detail) that I've skipped over in passing.

#g
--


On 06/04/2012 21:36, Paul Groth wrote:
> Hi Graham,
>
> Just for clarification, given that you think prov-dm is not ready for
> release, it's important to understand what exactly could be done to
> get it to the point where it is.
>
> Reading through your points, it seems to me that your comments are
> primarily editorial, in that it's the explanation, definition and
> organization of the terms that is the issue. Is that a correct
> interpretation?
>
> If not, can you identify the specific things that would need to be
> addressed for us to move forward on prov-dm?
>
> Regards
> Paul
>
>
> On Fri, Apr 6, 2012 at 9:51 PM, Graham Klyne<graham.klyne@zoo.ox.ac.uk>  wrote:
>> Re:
>> http://dvcs.w3.org/hg/prov/raw-file/default/model/releases/ED-prov-dm-20120402/prov-dm.html
>> (Retrieved on 2012-04-03)
>>
>> While this has many improvements over previous documents, I still feel that
>> there are several respects in which the document does not really serve its
>> intended purpose.
>>
>> Generally, I found the tone and phrasing were more akin to academic rhetoric,
>> whose purpose is to persuade a peer of the truth of some proposition, than a
>> technical standard whose aim should be to *specify*, *inform* and where
>> necessary to *explain*.  Especially for developers who will have to use this
>> material as a reference source.  Thus, I found much of what I read, particularly
>> in the introductory section, had far to much justification (some of which was
>> obvious, other aspects of which were just "noise") which didn't help to to
>> understand what was being presented, or how to use it.
>>
>> I also still have problems with the overall organization.  In particular, I
>> (still) find the example in section 3 breaks the hoped-for flow between the
>> section 2 overview (which I also now think is mis-titled) and the provenance
>> expression details in section 4.  I also don't think the final two subsections
>> of section 2 belong there, as they deal with provenance expression details, not
>> concepts.
>>
>> Finally, I found many examples of unusual or awkward phrasing which I found to
>> be unhelpful, confusing or in some cases just plain wrong.
>>
>> To summarize: if we expect the next public working draft to be nearly ready for
>> last, then I don't think this document is ready for release.
>>
>> Details follow.
>>
>> ...
>>
>>
>> == Abstract ==
>>
>> The phrase "derivations between entities" is strange and confusing.  I think you
>> mean something like "derivation of entities from other entities".
>>
>> "Properties that link entities that refer to a same thing".  I think this is
>> just wrong:  I don't believe that entities *refer*.  I think you mean something
>> like "Properties that link entities that are based on the same thing".
>>
>> "collections of entities, whose provenance itself can be tracked" - this feels
>> vaguely ungrammatical, and I'm not quite sure what this is trying to express.
>> In any case, I'll argue later that I don;t see why this is necessary as part of
>> the provenance core model.  (What I'm not seeing here is anything I can
>> recognize as the notion of accounts, which allow for provenance of provenance to
>> be expressed.)
>>
>> Here, and later in the document, there are references to "natural language".  I
>> believe this is a term of art that is meaningful only to those who have exposure
>> to formal languages, as a way of distinguishing, and may be confusing to some
>> readers.  In the abstract, I'd suggest just dropping this - the rest of the
>> sentence carries the intended meaning.
>>
>> I'm not sure what you mean by "systematically defines".  Just "defines" would
>> do, I think.
>>
>> == Status of this document ==
>>
>> The heading "how to read this document" is, I think, both patronizing and
>> inaccurate.  And the following comments seem to significantly replicate the
>> content of the preceding text.  I'd suggest moving descriptive material about
>> the documents into the preceding text, and drop the stuff that tries to tell
>> people what to read.
>>
>> "Fourth public working draft".  Really!!  Are we really up to 4 with this?  I
>> lose count.
>>
>> == Introduction ==
>>
>> "how it should be integrated with other diverse information sources".  I find
>> this phrase to be vague and unclear, and hence unhelpful.  I'd suggest dropping
>> this, and changing "... help those users to make trust judgements" in the next
>> sentence to read:
>>
>> "... help those users to decide which information to include in their analyses,
>> and which to exclude."
>>
>> "The idea that ... a pragmatiuc approach is to consider ..." add's no useful
>> value.  I suggest replacing all of this with "We consider ...".
>>
>> "the vision is that" is pure noise.  Suggest deleting this.  This whole
>> paragraph seems to be an unnecessary repetition of what the previous says.
>> While I sometimes think that a repeated summary can be useful, in this case I
>> think it would be more helpful to simplify the preceding paragraph.
>>
>> The material that starts with "A set of specifications, ..." seems to be pure
>> repetition of material contained in the "status of this document" - is it really
>> necessary to repeat it here?
>>
>> The listing of "components!" seems to be greatly redundant.  Each component is
>> both numbered (N) and introduced as "component N".  I think a simple numbered
>> list without the "component N" tags would suffice.
>>
>> Two paragraphs starting with "This specification intentionally presents..." -
>> these paragraphs are loaded with unnecessary self-justification.  I think a
>> simpler statement along the lines of:
>>
>> "This specification presents the key concepts of the PROV data model and
>> provenance expressions, without specific concern for how they are applied.  A
>> companion document [PROV-DM-CONSTRAINTS] discusses some possible constraints on
>> the application of this model, and corresponding useful inferences that may be
>> available when those constraints are known to be satisfied."
>>
>> [[The next comment is rendered moot if the previous one is accepted...]]
>> Paragraph: "However, if data changes...".  To an uninitiated reader, it is not
>> at all clear what is meant by "data" here.  I'd suggest something like "If a
>> thing about which provenance is expressed is subject to change, it is
>> challenging to express its provenance precisely (e.g. the data from which a
>> daily weather report is derived will change from day to day)."  Drop the
>> reference to other metadata here - it adds nothing of value.
>>
>> @@(note to self) raise a separate issue about how to describe this "refinement".
>>   I know I have argued for "refinement" over the idea of an "updated" or
>> "modified" provenance model, but the term is still a bit vague.  I find myself
>> leaning toward a notion of a "strict" interpretation of provenance that in turn
>> allows certain inferences to be drawn if the supplied provenance satisfies
>> certain strictness criteria (constraints).
>>
>> == 1.2 PROV namespace ==
>>
>> This section glibly introduces the notion of a "namespace" without explaining
>> (or citing) what it means.
>>
>> "The PROV namespace is http://www.w3.org/prov#".  This is WRONG.
>> http://www.w3.org/prov# is a URI, not a namespace (or, more precisely, it's a
>> string that conforms to URI syntax).
>>
>> What should be said is something like: "The names for concepts, attributes and
>> other reserved names introduced by this document belong to a namespace
>> identified by the URI http://www.w3.org/prov#".
>>
>> And: what is the consequence of these names belonging to a namespace?  I think
>> it would be appropriate to cite the corresponding XML and RDF documents that
>> deal with namespace issues [1] [2].
>>
>> [1] http://www.w3.org/TR/REC-xml-names/
>>
>> [2] http://www.w3.org/TR/REC-rdf-syntax/ (sections 6.1.2, 6.1.4, etc.  These
>> define how RDF/XML forms a URI-reference by appending a local name to a
>> namespace URI.)
>>
>> == Section 2, PROV-DM staring points ==
>>
>> I think this section is mis-titled.
>>
>> I think it should be: "2. Introduction to provenance concepts", since that is
>> what most of the section is about.
>>
>> In light of this, the final two sub-sections seem mis-placed, and I suggest they
>> should be part of the early material in section 4.
>>
>> "... that a novice reader would write in a first instance".  Yuk!  How
>> patronizing!  Also, a reference here to "natural language" (see previous).  I
>> would phrase this whole paragraph thus:
>>
>> "This section introduces provenance concepts with informal descriptions and
>> illustrative examples.  Later (section @@ref), we describe how these concepts
>> are described using PROV-DM types and relations."
>>
>> (where @@ref should be in another section that actually deals with PROV-DM terms.)
>>
>> == 2.1 Entity and Activity ==
>>
>> "The term things encompasses..." - I find this phrasing awkward and potentially
>> confusing - are we talking here about things or entities?  I suggest simply
>> "These encompass ..."
>>
>> The final sentence is mostly noise.  Why not just "Any Web resource may be an
>> entity."?
>>
>> "For the purpose of this specification..." is just noise.  Also, confusing
>> reference to "entities" and "things".  Suggest for this para:  "An entity is a
>> thing one wants to provide provenance for, which may be physical, digital,
>> conceptual, or otherwise; entities may be real or imaginary."
>>
>> "This action can take multiple forms: ..." - this is confusing; are we talking
>> about a single activity having multiple forms, or different activities having
>> different forms.  I think you mean the latter, hence I suggest: "An activity is
>> something that occurs over a period of time and acts upon or with entities. They
>> may include consuming, processing, transforming, modifying, relocating, using,
>> generating, or other associations with entities."
>>
>>
>> == 2.2, et seq. ==
>>
>> I find similar issues with the wording of subsequent sections, but I haven't
>> gone through every one for lack of time.  But I hope you get the general thrust
>> from the above.
>>
>>
>> == 2.3 Agents and other types of entities ==
>>
>> I think this exhibits poor organization of the material.  I think Agents and
>> Plans are related, and suggest a sub-section for them.  Collections and accounts
>> don't have any obvious relationship, and IMO should be separated.
>>
>> Concerning collections, it is not at all clear to me that these need to be in
>> the core PROV-DM.  By including them here, you impose a particular view of
>> collections that may not be appropriate  (somewhere, though I can't immediately
>> find where, there is mention of a collection being a key-value map).  Domains
>> that deal with collections have their own models for these, so why not let this
>> be an aspect for domain-specific extension?
>>
>>
>> I think accounts should have a section of their own, since they underpin the key
>> feature of supporting provenance0-of-provenance.
>>
>> However, I have a problem with the description "An account is an entity that
>> contains a bundle of provenance descriptions."  I think that this should be "An
>> account *is* an entity that is a bundle of provenance descriptions."  That is, I
>> don't think the core DM needs to or should expose the notion of containment,
>> since that begs more questions.
>>
>> == 2.4 Attribution, association and responsibility ==
>>
>> I find the expression of these ideas to be hopelessly muddled, and incoherent.
>> In particular, it seems to be self-contradictory with respect to the notion of
>> "responsibility" (also with section 2.3):
>>
>> "An agent is a type of entity that bears some form of responsibility for an
>> activity taking place."
>> "Software for checking the use of grammar in a document may be defined as an agent"
>> "Agents are defined as having some kind of responsibility for activities."
>> "[an association may be] an XSLT transform launched by a user ..."
>> "An activity association is an assignment of responsibility to an agent for an
>> activity"
>> "Responsibility is the fact that an agent is accountable for ..."
>>
>> At heart, I think the problem here is the notion that agents are "responsible".
>>   Especially when "responsibility" is later defined in terms of accountability -
>> I can't see a software agent as being accountable.  I don't know how to make
>> sense of this, so it's hard for me to suggest alternatives.
>>
>> == Section 2.5, Simplified overview diagram ==
>> == Section 2.6, PROV-N ... ==
>>
>> See earlier comments.  These is about PROV-DM terms, not provenance concepts, so
>> I don't really think they belong here.
>>
>> I'd move them to start start of section 4.
>>
>> == Section 3, Illustration... ==
>>
>> I *still* think the positioning of this example disrupts the logical flow from
>> concepts (section 2) to PROV-DM expressions (section 4).
>>
>> (I haven't reviewed the content of this section.)
>>
>>
>> == 4. PROV-DM types and relations ==
>>
>> The enumeration of components seems to be repetitive.  Numbered items *and*
>> component numbers?  (See earlier comment.)
>>
>> "In the first column, one finds concept names directly linking to their English
>> definition. In the second column, ...".  Why not just use column headings in the
>> table?  The reference to "English" description seems redundant.
>>
>> "In the rest of the section, each concept and relation is defined, in English
>> initially, followed by a more formal definition and some example."  Similar
>> comment.  Suggest:
>> "In the rest of the section, each type and relation is defined informally,
>> followed by a summary of the information used to represent the concept, and
>> illustrated with PROV-N examples."
>>
>> == 4.1.1 Entity ==
>>
>> "An entity is a thing one wants to provide provenance for. For the purpose of
>> this specification, things can be physical, digital, conceptual, or otherwise;
>> things may be real or imaginary."  confuses entities and things again.  Suggest:
>> "An entity is a thing one wants to provide provenance for. It can be physical,
>> digital, conceptual, or otherwise, and may be real or imaginary."
>>
>> "An entity, written entity(id, [attr1=val1, ...]) in PROV-N, contains:" - I
>> think this is wrong - an entity does not (in general) *contain*.  Suggest:
>> "An entity, written entity(id, [attr1=val1, ...]) in PROV-N, has:"
>>
>> "id: an identifier for an entity;" - this is redundant and potentially
>> confusing.  Suggest "id: an identifier".
>>
>> "attributes: an optional set of attribute-value pairs ((attr1, val1), ...)
>> representing this entity's situation in the world." - I find this phrasing
>> awkward and unclear.  Suggest:
>> "attributes: an optional set of attribute-value pairs ((attr1, val1), ...)
>> representing additional nformation about this entity."
>>
>> == 4.1.2, et seq ==
>>
>> (Similar editorial comments to those for 4.1.1 Entity.  I'm not repeating them
>> all now for lack of time.)
>>
>>
>> == Section 4.1.5 Start ==
>>
>> I find this whole section is confusing.  Starting with:
>>
>> "trigger: an optional identifier (e) for the entity triggering the activity;" -
>> do you really mean to allow *any* entity here, rather than just agents?
>>
>> Looking forward to the example, I find the idea that an email (qua entity) can
>> "trigger" an activity is incoherent.  Suppose the email is drafted and never
>> sent.  It still exists as an entity, but can't be said to actually *trigger*
>> anything.  For me, it is the act of actually sending (or receiving) an email
>> that may trigger something, not the email as a passive entity.
>>
>>
>> == Section 4.1.6, End ==
>>
>> (Similar comments to those above.)
>>
>>
>> == Section 4.1.7, Communication ==
>>
>> It seems strange to me, given the pattern used for other concepts/expressions,
>> that the communicated entity cannot be optionally named.  I find myself
>> wondering if I've understood the definition properly.
>>
>>
>> == Section 4.2.1, Agent ==
>>
>> Continues the muddle about responsibility.  I don't know what it all means
>> (especially when the agent is running software).  See previous comments.
>>
>> Awkward and unnecessary phrase "situation in the world" again.  See earlier for
>> suggested phrasing.
>>
>>
>> == Section 4.3.1 Derivation ==
>>
>> "A derivation is a transformation of an entity into another, a construction of
>> an entity into another, or an update of an entity, resulting in a new one."
>> seems ungrammatical.  Suggest:
>> "A derivation is a transformation of an entity into another, a construction of
>> an entity *from* another, or an update of an entity, resulting in a new one."
>>
>>
>> == Section 4.5 Collections ==
>>
>> I'm not understanding why this needs to be part of the core PROV-DM, and cannot
>> be habdled by domain specific notions of aggregation.
>>
>> The stated goal is that "it is also of interest to be able to express the
>> provenance of the collection itself" - this could be done equally well with a
>> domain-specific collection notion, AFAICT.
>>
>> See also earlier comments.
>>
>>
>> == Section 4.6, Annotations ==
>>
>> I'm still not seeing why these are needed as part of the core DM. There's no
>> associated inference that I am aware of, and additional information can be added
>> via attributes, so I'm not seeing what useful additional expressive capability
>> this affords.
>>
>>
>> == Section 4.7.4 Attribute ==
>>
>> Is an attribute really just a qualified name, or is it a pair consisting of a
>> qualified name and a value?
>>
>>
>> == Section 5, Extensibility points ==
>>
>> This section makes little sense to me.  The obvious extensibility points of
>> sub-typing and sub-properties of defined PROV-DM terms isn't mentioned.
>>
>> The use of new attributes seems reasonable, though it's not entirely clear how
>> they act as extension points, and the mention of "perspective on the world"
>> doesn't mean anything to me.
>>
>> I cannot see how notes, which are defined to be pretty much semantics-free, can
>> be described as an extensibility point - they don't actually add any expressive
>> power that I can see.
>>
>> The remaining points I just don't get.
>>
>> I think this whole notion of extensibility needs to be treated more carefully
>> and comprehensively if it is to be taken seriously.  Otherwise expect developers
>> to ignore this and just use extensibility options in the representation
>> substrate (e.g. RDF) used.
>>
>> == Section 6 ==
>>
>> I think this section is completely redundant and out-of-place, and could be
>> removed without any loss.
>>
>> ...
>>
>> That's it for now.
>>
>> (BTW, my email access is patchy, so I may not be able to respond promptly to any
>> follow-up discussion.)
>>
>> #g
>> --
>>
>>
>>
>>
>>
>
>
>
Received on Saturday, 7 April 2012 15:58:05 GMT

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