Re: [model] Why Motivations cannot be on Bodies

Hi, Rob–

Thanks for taking the time and effort to explain this.

I'm afraid the rationale still eludes me, though I reread your email 
several times.

In particular, I have difficulty justifying the assertion that the 
bodies are by necessity global resources, not local to the annotation. 
Outside the context of the annotation, you lose all other context, 
including the target and the provenance. So, how is a global body 
without context a useful statement? And even granting that it is 
theoretically useful, if the annotation data model is made rather more 
complicated by including this concept, is that a compromise worth making 
in the data model?

I also didn't understand your claim that you can't make an assertion 
about a segment of an image, just because other assertions can be made 
about it.

Maybe I'm simply not understanding something. Perhaps some concrete 
examples, possibly with images, would help? I know that seems like a lot 
of work just for me to understand it, but if I have this difficulty, I 
think others may too, if not in this WG, then out in the community of 
developers.

Regards–
–Doug

On 6/18/15 12:50 PM, Robert Sanderson wrote:
>
> Apologies in advance as this likely reads as lecturing, but there's a
> lot of background that needs to be understood (or at least accepted) to
> explain why motivations cannot be directly associated with bodies.
>
> Linked Data and RDF assume a globally scoped, open world model, in which
> anyone can make any assertion about any resource, and the context of
> that assertion is not at all relevant.  Thus if I make the assertion
> that a photo depicts Paris, and someone else makes an assertion that the
> same photo depicts Tokyo (they both have big towers after all), that's
> completely acceptable.  If this wasn't the case, then there would be
> semantic battles in the same way as wikipedia has edit wars, but in a
> fully distributed system.  Further, if something is not asserted, then
> it is assumed to be unknown, not false.  Just because I've asserted that
> the photo depicts Paris doesn't make it wrong, a priori, that it also
> depicts Tokyo (it could be a montage).  It would also depict many other
> things beyond Paris even if it didn't depict Tokyo.
>
> The side effect of this is that when you want to make explicit claims
> about resources that are only true in a particular context, you cannot
> make the claim about the resource in general.  As bodies (and targets)
> of Annotations are web resources, not properties of the Annotation, if
> we want to make claims about that resource in the context of the
> annotation, we need a new resource ... which is a Specific Resource.
>
> We already have this in the model to enable Selectors, States, Styles
> and Scope.  You cannot make an assertion that an image has a segment
> described by a Selector, as many annotators might annotate different
> segments of the same image.  In the open world, all of those selectors
> are possible and true ... so when looking at the graph you cannot
> distinguish which selector belongs to which annotation.
>
> Thus the Specific Resource stands for the Body or Target in the specific
> context of the Annotation.  We can safely make assertions about the
> Specific Resource, as we just created it for that purpose, without
> colliding with other annotations' assertions.
>
> Given that bodies have the same required features as targets, we have
> Specific Resources for bodies.  For example, we could otherwise not say
> "this part of this web page is about that part of that image".  Or this
> blog at this point in time is about that news article.  This part of
> this video is about that part of that data set. And so forth.
>
> Thus, and there will be a test on this next class, we cannot make
> annotation specific assertions about either the body or the target
> directly on the resource and motivation is (clearly) an annotation
> specific assertion, not a global one. We already have a solution for
> that, which is the specific resource construction.  This leads to the
> proposal to allow motivatedBy on specific resources. (Or potentially and
> more radically, to an alternative to do away with multiple bodies
> completely and have annotation sets as first class objects)
>
>
> Thanks and hope that helps!
>
> Rob
>
>
> --
> Rob Sanderson
> Information Standards Advocate
> Digital Library Systems and Services
> Stanford, CA 94305

Received on Thursday, 18 June 2015 17:32:33 UTC