linked data: building standards and communities
TRANSCRIPT
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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Linked Data in Practice: Building Standards, Building Communities
Robert Sanderson [email protected] // [email protected] // @azaroth42
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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Overview
• Standards • Linked Data: Advantages and Challenges
• Graph Structure • Open World • Ontologies and Identities • Serialization Formats
• Communities
WARNING: Packaged in a Factory Containing Controversy
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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Standards
Standards are essential: Infrastructure like Electricity Like Electricity, there can be more than one but having
the adapters is always a pain Or Standards like USB...
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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Building Standards
Standards are about agreement. Technical side is easy compared to getting community
engagement and support. (Much like herding cats)
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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Building Web Standards
The web has revolutionized communication, especially scholarly communication. Any modern communication standard
needs to be a web standard Web Standards are about linking things together. Web Standards are about data. Linked Data is done using a Graph,
expressed in a technical framework called RDF
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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Graphs
ü Graphs are very powerful for modeling reality ü Tree (like XML) is just a simple Graph ü Don’t end up in semantic/syntactic hell (like XML)
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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Graphs: Structure and Data
Ø Working with graphs must take structure into account
Graph: Structure and Data important, but data currently treated as second class citizen Other: Only Data important, so easier to work with • Can’t think about “documents” as all nodes/edges
are stored together
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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Graphs: Structure and Data
Ø Visualization is difficult to get right Ø … and hard to know when it is right
Ø Documents “easy” to visualize
Ø Graph visualization almost universally terrible … because has to take structure into account
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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Visualization Done Right
http://www.facebook.com/note.php?note_id=469716398919
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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Not So Right
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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Graphs
Other structures don’t get as complicated because they lack the expressiveness of a graph
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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The Open World
ü A Single Global Graph that everyone contributes to ü Great for data re-use ü Global identities ü Richness of data from multiple sources ü Distributed: Can incrementally add to others descriptions ü Fits with the WWW: The Data Web
Technically: If a statement is not asserted, then its truth-value is
unknown, rather than false. Data: Painting has X’s signature Question: Does the painting have Y’s signature? Closed World: No Open World: I Don’t Know
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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The Open World: Global Identities
Jon publishes an Annotation about part of a web page.
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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The Open World: Global Identities
Brewster archives the page … and says where it is.
ü Without modifying the annotation at all!
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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The Open World: Local Complexity
Ø Every assertion is considered true in all contexts
Q: How do we say that Canvas 2 comes after Canvas 1, and Canvas 3 comes after Canvas 2?
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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The Open World: Ordering
Did you think this? Remember anyone can say anything, and it’s global…
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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The Open World: Ordering
Now there are two next links from Canvas 1, and our list is … a graph. Use Case: Manuscript has different page order at different times
Jane
Freya
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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The Open World: Ordering
ORE introduces proxy nodes, as not just order is local. Eg may wish to cite a resource in the context of a set of resources.
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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The Open World: Ordering
Shared Canvas uses multiple classes and the rdf:List construction. Serializations hide the list’s anonymous nodes.
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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Local identity for local context is good practice!
The Open World
Think Globally Identify Locally
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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ü Shared relationships increase interoperability ü dc:title is ‘name’ or ‘label’, not property title or Dr. ü Re-use of semantics makes it easier to build applications ü Communities can develop own ontologies of relationships
independently
ü Shared Identity makes it possible for graph to merge serendipitously ü Everyone can mint own IDs using http URIs ü By reusing ids, graphs will merge, creating new knowledge
Ontologies and Identities
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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Ø “The nice thing about … Ontologies … is that there’s so many to choose from” Ø Too many to choose from, hard to find the right one Ø If almost right, do you reuse and hope for the best, or
specialize and create yet another ontology?
Ontologies and Identities
http://xkcd.com/927/
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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Ø “The nice thing about … Identities … is that there’s so many to choose from” Ø Far far too many to choose from, hard to find the right one Ø As anyone can create identity for anything, they do Ø Identity can have a contextual component – does LANL’s
identifier for Oppenheimer differ from DBPedia’s?
Ontologies and Identities
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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Standards! Communities!
Ontologies and Identities
http://www.flickr.com/photos/clydeorama/6693882429/
House of Representatives from Huffington Post
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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ü The new JSON-LD format is pretty good
Serializations
{! "@context": "http://www.w3.org/ns/oa.json", ! "@id": "http://example.org/anno1", ! "@type": "oa:Annotation", ! "annotatedAt": "2012-11-10T09:08:07", ! "annotatedBy": {! "@id": "http://public.lanl.gov/rsanderson#me", ! "@type": "foaf:Person", ! "name": "Rob Sanderson"! }, ! “hasBody": {"chars": "This... is CNN.”}, ! “hasTarget": “http://www.cnn.com/”!}!
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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Ø The recommended RDF/XML is absolutely terrible Ø “RDF/XML was the Semantic Web’s 3 Mile Island incident”
-- Manu Sporny, http://manu.sporny.org/2012/nuclear-rdf/
Serializations
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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Building Community is hard! • W3C Community Groups • Funding • Engagement not Argument • Early Embedding • Merge when possible
Path may be longer together, but it’s better
Communities
Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA
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Slides: http://www.slideshare.net/azaroth42/
xxx-yyy Open Annotation: http://www.openannotation.org/
http://www.w3.org/community/openannotation/ Shared Canvas: http://www.shared-canvas.org/ http://iiif.io/
Rob Sanderson: [email protected] // [email protected] @azaroth42 // http://public.lanl.gov/rsanderson/
Thank You!