W3C home > Mailing lists > Public > public-annotation@w3.org > July 2015

Re: [model] Clarifying annotation architecture

From: Robert Sanderson <azaroth42@gmail.com>
Date: Thu, 23 Jul 2015 09:19:10 -0700
Message-ID: <CABevsUEbiAvq+A7Acq+Zz3R7JMtyvB6HijY_8RONV64HiNj5OQ@mail.gmail.com>
To: Frederick Hirsch <w3c@fjhirsch.com>
Cc: "Denenberg, Ray" <rden@loc.gov>, W3C Public Annotation List <public-annotation@w3.org>
Hi Frederick,

Yes, I totally understand the desire to use plain JSON, and why the
additional objects look unnecessary.  Your JSON looks very good, in that
context.

But that's not what we're doing, and if we were we would have a very
different model that didn't need to have things like SpecificResource at
all.  Again, if people care enough to understand the reasons, then that's
great.  If they don't, that's great, but arguing about whether something is
correct or not without understanding the requirements results in 100s of
emails across multiple threads.  Whether it's valuable of not ... it has
advantages and disadvantages. (see at the bottom if you care).

The context mapping in JSON-LD only the keys and values, it can't change
the structure. So it can't introduce new nodes/objects, move existing ones
around, or delete them.  There's one additional restriction, it can't do
lists of lists, because the processing to disambiguate what is meant at the
RDF level is significant.

So similarly, we can't map from a literal body directly to a body with a
resource/object in the context.  Either of those could be done with a
little bit of code in both the client and server ... but that would defeat
the purpose.

Rob

An overview of the ups and downs of RDF, especially slides 3-18:
  http://www.slideshare.net/azaroth42/rdf-resource-description-failures

Disadvantages:
* This situation where you need to create new resources to (essentially)
reify relationships.

Advantages:
* There's a global graph that everyone contributes knowledge to, rather
than a bunch of documents that are all stand-alone.
* There's rich data that you can use, without transforming it on a case by
case basis, as everything has a unique URI in a standardized framework
* Others can incrementally add information about your resources in a global
crowd-sourcing kind of way



On Thu, Jul 23, 2015 at 8:34 AM, Frederick Hirsch <w3c@fjhirsch.com> wrote:

> (not as chair)
>
> Rob
>
> yes that helps quite a bit.
>
> I still see a problem explaining to JSON (non-turtle, non-RDF,
> non-JSON-LD) people why what looks like straightforward JSON is wrong,
> since they don't care about SpecificResources and triples..
>
> if there were no JSON-LD and no linked data, the following *would be fine*
> JSON, right?
>
> {
>   "kind": "Annotation",
>   "target" : "some-uri.html",
>   "body": {
>     "source: "meme-image.jpg",
>     "role": "commenting"
>   }
> }
>
> This is why the problem is "non-obvious".
>
> Is there a way to transform this via implementation to using
> SpecificResource by default? Did this come up in the JSON-LD discussions?
>
> Does this make the issue clear from the JSON implementer point of view?
>
> regards, Frederick
>
> Frederick Hirsch
>
> fjhirsch.com
> @fjhirsch
>
>
> > On Jul 23, 2015, at 11:02 AM, Robert Sanderson <azaroth42@gmail.com>
> wrote:
> >
> >
> > Sure!
> >
> > Good:
> >
> > _:anno a oa:Annotation ;
> >   oa:hasTarget <some-uri.html> ;
> >   oa:hasBody _:specres .
> >
> > _:specres a oa:SpecificResource ;
> >   oa:motivatedBy oa:commenting ;
> >   oa:hasSource <meme-image.jpg> .
> >
> >
> > Bad:
> >
> > _:anno a oa:Annotation ;
> >   oa:hasTarget <some-uri.html> ;
> >   oa:hasBody <meme-image.jpg> .
> >
> > <meme-image.jpg> oa:motivatedBy oa:commenting .
> >
> >
> > (Or substitute some new predicate like oa:role or whatever, per Tim
> Cole's comment that specific resources aren't really motivated in the same
> way that annotations are)
> >
> > Hope that helps :)
> >
> > Rob
> >
> >
> > On Thu, Jul 23, 2015 at 7:58 AM, Denenberg, Ray <rden@loc.gov> wrote:
> > Rob – still trying to grasp this.  Could you show how this would look
> done the “right” way, I.e. as a specific resource,
> >
> >
> >
> > AND   please write both (the bad example and the good)  in turtle, not
> json-ld.
> >
> >
> >
> > Thanks.
> >
> >
> >
> > Ray
> >
> >
> >
> >
> >
> > From: Robert Sanderson [mailto:azaroth42@gmail.com]
> > Sent: Thursday, July 23, 2015 10:30 AM
> > To: Denenberg, Ray
> > Cc: Jacob Jett; Frederick Hirsch; W3C Public Annotation List
> >
> >
> > Subject: Re: [model] Clarifying annotation architecture
> >
> >
> >
> >
> >
> > We shouldn't (must not) do this:
> >
> >
> >
> > {
> >
> >   "@type": "Annotation",
> >
> >   "target" : "some-uri.html",
> >
> >   "body": {
> >
> >     "@id": "meme-image.jpg",
> >
> >     "role": "commenting"
> >
> >   }
> >
> > }
> >
> >
> >
> > As meme-image.jpg might have another role in a different annotation
> (replacing, in Doug's example)
> >
> >
> >
> > Rob
> >
> >
> >
> >
> >
> > On Thu, Jul 23, 2015 at 6:37 AM, Denenberg, Ray <rden@loc.gov> wrote:
> >
> > Hi Jacob – No, I’m afraid I don’t see that the “sky colored red” example
> applies to my question, however, if you (or someone) could write, in RDF
> syntax, an example annotation, which does specifically what it is we are
> saying we shouldn’t do …  specifically: attach a motivation to a body  (and
> more specifically, where the body is an image or some other non-rdf
> resource) ... that would help.
> >
> > Thanks.
> >
> >
> >
> > Ray
> >
> >
> >
> > From: jgjett@gmail.com [mailto:jgjett@gmail.com] On Behalf Of Jacob Jett
> > Sent: Wednesday, July 22, 2015 5:16 PM
> > To: Denenberg, Ray
> > Cc: Robert Sanderson; Frederick Hirsch; W3C Public Annotation List
> >
> >
> > Subject: Re: [model] Clarifying annotation architecture
> >
> >
> >
> > Hi Ray,
> >
> >
> >
> > This is a distinctly RDF thing. Essentially the triples are all distinct
> assertions.
> >
> >
> >
> > Imagine that I told you, "the sky is red". In ttl we might write the
> assertion this way --
> >
> >      Sky colored Red .
> >
> >
> >
> > This statement is true at certain points in time. Unfortunately RDF does
> not have a way to scope the assertion to certain points in time (or in the
> roles example, specific contexts). So from the SemWeb perspective "Sky
> colored Red ." and "Sky colored Blue ." are both true at all times and in
> all places. Using the specific resource allows us to scope the assertions,
> e.g., Sky@time@place colored Red .
> >
> >
> >
> > Is that example helpful at all?
> >
> >
> >
> > I think Rob's suggestion is a reasonable work around for this role
> issue. It should be invisible to those who don't care about SemWeb issues
> and makes the data reasonably actionable for those who do.
> >
> >
> >
> > Regards,
> >
> >
> >
> > Jacob
> >
> >
> >
> >
> >
> > _____________________________________________________
> >
> > Jacob Jett
> > Research Assistant
> > Center for Informatics Research in Science and Scholarship
> > The Graduate School of Library and Information Science
> > University of Illinois at Urbana-Champaign
> > 501 E. Daniel Street, MC-493, Champaign, IL 61820-6211 USA
> > (217) 244-2164
> > jjett2@illinois.edu
> >
> >
> >
> > On Wed, Jul 22, 2015 at 4:00 PM, Denenberg, Ray <rden@loc.gov> wrote:
> >
> > There is a fundamental piece of this that I’m missing.
> >
> > {
> >
> >   "@type": "Annotation",
> >
> >   "target": "some-uri.html",
> >
> >   "body": {
> >
> >     "@type": "SpecificResource",
> >
> >     "motivation" : "editing",
> >
> >     "source": "meme-image.jpg"
> >
> >   }
> >
> >
> >
> > You create a new resource (specific resource) in order to associate a
> motivation (editing) with the original resource (source).
> >
> >
> >
> > And you do this to avoid  “directly assigning a role to the original
> resource”.
> >
> >
> >
> > I understand the reason why.  What I don’t understand is how it is
> proposed to do the latter in the first place.  In the example, the original
> resource is an image. Not like it’s an RDF description that you can stick
> an RDF  triple into.
> >
> >
> > What am I missing here?
> >
> >
> >
> > Ray
> >
> >
> >
> >
> >
> > From: Robert Sanderson [mailto:azaroth42@gmail.com]
> > Sent: Wednesday, July 22, 2015 2:45 PM
> > To: Frederick Hirsch
> > Cc: W3C Public Annotation List
> > Subject: Re: [model] Clarifying annotation architecture
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > > * Associate the role with the body directly.  Fails because it makes
> the body un-reusable, which for the image/video or similar case is not
> acceptable.
> >
> >
> >
> > This statement is a key issue and I think Doug was asking about this as
> well during the call.
> > The failure scenario is not clear. Un-resuable  : re-used by whom and
> for what?
> >
> >
> >
> > Reused anywhere by anyone for anything, but most importantly reused as a
> body in a different annotation with a different role.
> >
> > As per Doug's example, you could not use the meme image as a comment in
> one annotation and a replacement in another annotation.
> >
> >
> >
> >
> >
> > If I forget the semantic web (for a moment) I can have an object, say a
> body, that has properties, including hasSegment or role and two bodies
> could have different values for the properties.
> >
> >
> >
> > Sure. If I forget that I need to close my tags and put quotes around my
> single token attributes, I end up with SGML ... but that sure isn't XML.
> Or if we conveniently forget about HTTP requirements, we could not worry
> about all those pesky headers. We could just stuff everything in the URL
> ... that would be much simpler, no? Then you would only ever need to do a
> GET, and could type it into your browser bar.
> >
> >
> >
> >
> >
> > The only re-use issue would be an implementation optimization (e.g. I
> don't want to duplicate an embedded image/video to save space)
> >
> > In semantic web terms:
> > annotation1 has body1.
> > annotation1 has body2.
> > body1 hasRole A.
> > body2 hasRole B.
> >
> >
> >
> > annotation2 has body1
> >
> > body1 hasRole B.
> >
> >
> >
> > Now body1 has both A and B roles.
> >
> >
> >
> >
> >
> > so where is the problem, and where is the re-use?
> >
> >
> >
> > There was no problem until someone else (annotation2) also assigned a
> different role to the body, and now it has both of them at once.
> >
> >
> >
> >
> >
> > > * Associate the role (motivation) with a specific resource. Works as
> expected without changing the semantics, breaking linked data, or
> introducing any new classes or properties.
> >
> > isn't a body a resource? If it isn't a resource, what is it?
> >
> >
> >
> > Well... the preferred answer would be yes, it's a resource.  But it's
> also a literal string :P
> >
> > However snark aside, I'm not sure as to what's prompting the question?
> >
> >
> >
> > Perhaps to clarify the bullet:  ... with a oa:SpecificResource.
> >
> >
> >
> > {
> >
> >   "@type": "Annotation",
> >
> >   "target": "some-uri.html",
> >
> >   "body": {
> >
> >     "@type": "SpecificResource",
> >
> >     "motivation" : "editing",
> >
> >     "source": "meme-image.jpg"
> >
> >   }
> >
> > }
> >
> >
> >
> > R
> >
> >
> >
> >
> >
> > --
> >
> > Rob Sanderson
> >
> > Information Standards Advocate
> >
> > Digital Library Systems and Services
> >
> > Stanford, CA 94305
> >
> >
> >
> >
> >
> >
> >
> >
> > --
> >
> > Rob Sanderson
> >
> > Information Standards Advocate
> >
> > Digital Library Systems and Services
> >
> > Stanford, CA 94305
> >
> >
> >
> >
> > --
> > Rob Sanderson
> > Information Standards Advocate
> > Digital Library Systems and Services
> > Stanford, CA 94305
>
>
>
>
>
>


-- 
Rob Sanderson
Information Standards Advocate
Digital Library Systems and Services
Stanford, CA 94305
Received on Thursday, 23 July 2015 16:19:39 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 18:54:38 UTC