Use Cases for Choice, Composite, and List

Hi all,

Doug asked about the use cases for the multiplicity types in the current
draft of the model. A well developed set of these use cases (sans examples
in json or ttl) can be found in the Community Group's dpub use cases
document: http://w3c.github.io/dpub-annotation/

A more detailed explanation for where these three things (Choice,
Composite, and List) originated from is as follows.

Section 5 (Mulitplicity) of the data model arose out of a consesus in the
Community Group to accommodate several use cases that were developed during
the early OAC work. A discussion of them can be found in the Community
Group Archives.[1]

The use case for oa:List emerged from work on annotating videos that took
place at MITH (U. Maryland). It quickly emerged that multiple selectors
would be necessary in order for specific time-space regions of videos to be
annotated. This issue appears (somewhat under-developed) in the OACG
wiki[2] and MITH's final report (where an earlier attempt at accommodating
it (oa:CompositeSelector) is illustrated.[3] During one of the early CG
meetings it was pointed out that you wouldn't apply the selectors at the
same time (i.e., "composite" has semantic senses other than that of list or
ordered list) and so oa:List emerged.

Example 63 in the current FPWD showcases the expected pattern for
oa:List.[4]

{
  "@id": "http://example.org/anno1",
  "@type": "oa:Annotation",
  "body": {"@id": "http://example.org/body1"},
  "target": {
    "@id": "http://example.org/sptarget1",
    "@type": "oa:SpecificResource",
    "source": "http://example.org/target1",
    "selector": {
      "@type": "oa:List",
      "members": [
        "http://example.org/selector1",
        "http://example.org/selector2"
      ]
    }
  }
}

Another place where this might be used is in the editing use case. Imagine
a single user who creates a batch of edits through a single annotation
(IIRC this is similar to Bob Morris's Filtered Push and Lutz's use cases).

{
  "@id": "http://example.org/anno1",
  "@type": "oa:Annotation",
  "motivation": "editing",
  "body": {
    "@id": "http://example.org/list_body1",
    "@type": "oa:List",
      "members": [
        "http://example.org/edit1",
        "http://example.org/edit2",
        "http://example.org/edit3",
        "http://example.org/edit4",
        "http://example.org/edit5",
  },
  "target": {"@id": "http://example.org/target1"}
}

There several ways of making this complex annotation even moreso, all
having to do with adding additional bodies or members with different roles.
I'll defer those to a later date (hopefully much later).

List's sister oa:Composite was (as noted above) was the first attempt to
provide something unordered. Unfortunately there's really no such thing as
an unordered list, they just come with an arbitrary order or an enumerated
order. Some early deliberations of the OACG suggested that it be eliminated
altogether[5]

The notion of composites was re-developed to satisfty a use case that came
out of OAC work here at Illinois. Scholars' need to be able to forge a
single target comprising two juxtaposed images [6] (see especially section
4.3 of [6]) was the driving use case for the development of oa:Composite.
And the use case fully developed and documented in the OACG's electronic
publishing oriented use case document[7] at [8] and [9] respectively
(although there are no illustrative examples in this document).

The current FPWD lays out the expected pattern with example 61 (below).[10]

{
  "@id": "http://example.org/anno1",
  "@type": "oa:Annotation",
  "body": {"@id": "http://example.org/body1"},
  "target": {
    "@type": "oa:Composite",
    "item": [
      "http://example.org/target1",
      "http://example.org/target2"
    ]
  }
}

The notion of oa:Choice emerged similarly to that of oa:List. In the
beginning it was intended to operate with Selectors. It quickly became
apparent during the face-to-face meetings that it also had a valuable
purpose in the context of bodies and targets, the generalities of which are
recorded in OACG wiki[11] and the OACG use case document[7], especially at
section 2.3. [12]

The current FPWD lays out the expected pattern in example 59 (below).[13]

{
  "@id": "http://example.org/anno1",
  "@type": "oa:Annotation",
  "body": {
    "@type": "oa:Choice",
    "members": [
      "http://example.org/body1",
      "http://example.org/body2"
    ]
  },
  "target": "http://example.org/target1"
}



1:
https://lists.w3.org/Archives/Public/public-openannotation/2012Oct/0004.html
2: https://www.w3.org/community/openannotation/wiki/Issue_lists
3:
http://openannotation.org/documents/ProjectReports/MarylandFinalReport.pdf
4: http://www.w3.org/TR/annotation-model/#list
5: https://www.w3.org/community/openannotation/wiki/Issue_composite
6:
http://openannotation.org/documents/ProjectReports/EmblematicaFinalReport.pdf
7: http://w3c.github.io/dpub-annotation/
8:
http://w3c.github.io/dpub-annotation/#annotation-comparing-segments-within-a-publication
9:
http://w3c.github.io/dpub-annotation/#annotation-comparing-segments-between-publications
10: http://www.w3.org/TR/annotation-model/#composite
11: https://www.w3.org/community/openannotation/wiki/Issue_choicelists
12: http://w3c.github.io/dpub-annotation/#advanced-annotation-use-cases
13: http://www.w3.org/TR/annotation-model/#choice




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