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Linked Data: Building Standards and Communities
This document discusses standards and communities for linked data. It emphasizes that standards are important for infrastructure and interoperability, but getting community engagement and support is challenging. It describes how linked data uses graph structures and the open world assumption to allow data from multiple sources to be connected and new knowledge to emerge. However, the open world assumption also means local contexts need identities. It stresses that communities are important for building consensus around ontologies and identifiers. Different serialization formats for linked data like JSON-LD are also discussed.
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Linked Data: Building Standards and Communities
- 1. Linked Data inPractice: Building Standards, Building Communities rsanderson@lanl.gov Robert Sanderson // azaroth42@gmail.com // @azaroth42 Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA 1
- 2. Overview • Standards • LinkedData: 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 2
- 3. 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 3
- 4. Building Standards Standards areabout 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 4
- 5. Building Web Standards Theweb 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 5
- 6. Graphs ü Graphs arevery 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 6
- 7. Graphs: Structure andData 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 7
- 8. Graphs: Structure andData 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 8
- 9. Visualization Done Right http://www.facebook.com/note.php?note_id=469716398919 LinkedData in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA 9
- 10. Not So Right LinkedData in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA 10
- 11. Graphs Other structures don’tget 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 11
- 12. The Open World ü A Single Global Graph that everyone contributes to ü ü ü ü ü Great for data re-use Global identities Richness of data from multiple sources Distributed: Can incrementally add to others descriptions 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 12
- 13. 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 13
- 14. 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 14
- 15. 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 15
- 16. 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 16
- 17. The Open World:Ordering Jane Freya 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 Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA 17
- 18. 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 18
- 19. 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 19
- 20. The Open World Localidentity for local context is good practice! Think Globally Identify Locally Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA 20
- 21. Ontologies and Identities 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 Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA 21
- 22. Ontologies and Identities 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? http://xkcd.com/927/ Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA 22
- 23. Ontologies and Identities 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? Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA 23
- 24. Ontologies and Identities Standards!Communities! House of Representatives from Huffington Post http://www.flickr.com/photos/clydeorama/6693882429/ Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA 24
- 25. Serializations ü The newJSON-LD format is pretty good {! "@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 25
- 26. Serializations Ø The recommendedRDF/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/ Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA 26
- 27. Communities Building Community ishard! • W3C Community Groups • Funding • Engagement not Argument • Early Embedding • Merge when possible Path may be longer together, but it’s better Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA 27
- 28. Thank You! Slides: http://www.slideshare.net/azaroth42/ xxx-yyy Open Annotation: http://www.openannotation.org/ http://www.w3.org/community/openannotation/ SharedCanvas: http://www.shared-canvas.org/ http://iiif.io/ Rob Sanderson: rsanderson@lanl.gov // azaroth42@gmail.com @azaroth42 // http://public.lanl.gov/rsanderson/ Linked Data in Practice: Building Standards and Communities Yale Digital Collections Center, Nov 19 2013, New Haven CT, USA 28