Multiplicity and Publishing in Open Annotation (tutorial)

Open Annotation Data Model:
Multiplicity and Publishing Modules

Robert Sanderson
azaroth42@gmail.com
Los Alamos National Laboratory
@azaroth42

Paolo Ciccarese
paolo.ciccarese@gmail.com
Harvard Medical School
@paolociccarese

(Community Group Co-Chairs)

Open Annotation Community Group West Coast Open Annotation Rollout
http://www.w3.org/community/openannotation/ April 9th 2013, Stanford, CA, USA 1

Multiplicity

The Data Model allows for multiple bodies and multiple targets
•  Easiest: Multiple instances of hasBody, hasTarget
•  Issue: What are the semantics?

Multiples of hasBody/hasTarget: Treated individually

Requirements:
•  Choice: Only one resource needs to be displayed
•  Composite: All resources are required together, as a set
•  List: All resources are required together, with order


Multiplicity: Choice

Choice: Rendering agent should choose one resource to display
oa:default: The default resource of the Annotation’s producer
oa:item: Another possible resource


Multiplicity: Choice


Multiplicity: Composite

Composite: A set of resources, all of which are required to understand the
Annotation correctly


Multiplicity: Composite


Multiplicity: List


Publishing Annotations

The Data Model is only a model, not a protocol:
•  Does not specify interactions between client/server
•  Does not limit additional descriptive features
•  Does not specify annotation search, retrieval or management

Some aspects related to publishing are important:
•  Serialization of the model
•  Embedding resources
•  Including other graphs
•  Equivalence of resources


Publishing: JSON-LD Serialization

JSON-LD is the latest RDF serialization:
http://json-ld.org/spec/latest/json-ld/

Open Annotation recommends its use over RDF/XML:
•  Easier for developers
•  More web application friendly
•  Looks like JSON (with appropriate context)
•  So special parser not required
•  Easy to generate without special libraries

RDF/XML and Turtle are also recommended, if content negotiation is
supported.


Publishing: JSON-LD Context

JSON-LD has a Context description which maps JSON object keys to
RDF predicates, and assigns namespace prefixes:

{“@context”:{
“oa”: “http://www.w3.org/ns/oa#”,
“cnt”: “http://www.w3.org/2011/content#”,
“dc”: “http://purl.org/dc/elements/1.1/”,
…
“hasBody”: {“@type”:”@id”, “@id”:”oa:hasBody”},
“hasTarget”: {“@type”:”@id”, “@id”:”oa:hasTarget”},
…
“chars”: “cnt:chars”,
“format”: “dc:format”,
“when”: “oa:when”
…
}
}


Publishing: JSON-LD Example

Reuse of the Context definition makes simple annotations simple:

{
“@context”: “http://www.w3.org/ns/oa-context-20130208.json”,
“@type”: “oa:Annotation”,
“hasBody”: “http://www.youtube.com/watch?v=fgg2tpUVbXQ”,
”hasTarget”: ”http://zebu.uoregon.edu/hudf/hudf_300dpi.jpg”
}


Publishing: JSON-LD Example

And complex annotations still (somewhat) readable:

{
“@context”: “http://www.w3.org/ns/oa-context-20130208.json”,
“@id”: “http://www.example.org/annotations/1.json”,
“@type”: “oa:Annotation”,

“annotatedAt”: “2012-11-10T09:08:07”,
“annotatedBy”: {
“@id” : “http://www.example.com/people/rsanderson”,
“@type”: “foaf:Person”,
“mbox”: “rsanderson@example.com”},

“hasBody”: “http://www.youtube.com/watch?v=fgg2tpUVbXQ”,

…


Publishing: JSON-LD Example (cont)

”hasTarget”: {
”@id”: ”urn:uuid:1d823e02-60a1-47ae-bc872081729c”,
”@type”: ”oa:SpecificResource”,
”hasSelector”: {
”@id”: ”urn:uuid:6e353e12-30c2-98a3-39ff2081729c”,
”@type”: ”oa:FragmentSelector”,
”conformsTo”: ”http://www.w3.org/TR/media-frags”,
”value”: ”xywh=10,10,5,5”
}
”hasSource”: {
”@id”: ”http://zebu.uoregon.edu/hudf/hudf_300dpi.jpg”,
”@type”: ”dcterms:Image”
}
}


Publishing: Embedding Resources

Resources other than the body can benefit from being embedded:
•  SVG Selector
•  CSS Style

Potentially other resources:
•  When the resource is offline, and being sent along with the
annotation to a publishing server
•  For preservation
•  To include the exact representation, perhaps otherwise un-
obtainable


The Content in RDF specification is reused:


Publishing: Embedding RDF Graphs
It is useful to embed RDF graphs within the Annotation.
Prefer to use Content in RDF approach, but if Trig/Trix is requested:


Publishing: Embedding RDF Graphs


Publishing: Equivalent Resources
Useful to know that Annotations (and other resources) have been
duplicated between systems:


Publishing: Equivalent Resources


Extending Motivations
The Data Model defines only a few core Motivations

Intent is for communities to extend as necessary:
1.  Create a new ConceptScheme (vocabulary/taxonomy)
2.  Create a new instance of oa:Motivation
3.  Link new instance to at least one existing Motivation if possible
4.  Assign labels and other information to describe its use


Thank You

Robert Sanderson
azaroth42@gmail.com
Los Alamos National Laboratory
@azaroth42

Paolo Ciccarese
paolo.ciccarese@gmail.com
Harvard Medical School
@paolociccarese

(Community Group Co-Chairs)

http://www.flickr.com/photos/hinkeb/5232293964/

http://www.w3.org/community/openannotation/
http://www.openannotation.org/


Multiplicity and Publishing in Open Annotation (tutorial)

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