Semantic MediaWiki is an ideal tool for Linked (Open) Data. Tutorial at SMWCon 2020

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Linked (Open) Data with SMW
#SMWCon, November 26, 2020
Bernhard Krabina

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Semantic MediaWiki
 Collaborative data curation tool
 Metadata tool (Content + Metadata)
 Annotate data in texts
 Knowledge Graph Interface
 Web-based database
 Open-Source, with vibrant community
 Uses Semantic Web Standards
 Internal querying of data
 Importing and exporting of data
 Business logic can be implemented by
customization, without PHP programming

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The Web is evolving…

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Defining Linked Data

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5 Star-Schema of Linked (Open) Data

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Linked Data vs. Open data
26 November 2020 · Seite 6

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Open Data and SMW
 Make your SMW readable by everyone
 editing can still be restricted to logged-in users
 Include an open license
 see https://www.mediawiki.org/wiki/Manual:Copyright
 Make it easy for users to access your data:
 SMW puts a link to the RDF-representation (Special:ExportRDF) in the
HTML automatically, see https://www.semantic-
mediawiki.org/wiki/Help:RDF_export
 create an RDF Dump https://www.semantic-
mediawiki.org/wiki/Help:Maintenance_script_dumpRDF.php
 indicate exporting of data on pages or lists (e. g. vCard, iCalendar,
BibTex, KML)
 provide export pages with explanations and several result formats
(CSV, JSON, RDF)

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Example: FINA Wiki
 https://fina.oeaw.ac.at/wiki

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Linking to external identifiers
 Define a property
 Assign datatype
„External identifier“
 Links to external ids
 Look for other identifiers
 ORCID https://orcid.org/
 GND
 …..
[[Has type::External identifier]]
[[External formatter uri::http://www.wikidata.org/entity/$1]]

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Excursion: Service Links
 Only works in Special:Browse
https://github.com/SemanticMediaWiki/SemanticMediaWiki/issues/4020
Property:WikidataID [[provides service::wikidata]]
MediaWiki:Smw_service_wikidata:
Wikidata|http://www.wikidata.org/entity/$1

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Using External Vocabularies
 Add a page MediaWiki:Smw import foaf
 Instead of local datatype declarations, use
[[Imported from::foaf:familyName]]
on the property page (e. g. Property:Last name)
 To change a datatype, change it on MediaWiki:Smw
import foaf
 https://www.semantic-mediawiki.org/wiki/Help:
Import_vocabulary
 https://github.com/TIBHannover/ontology2smw/tree/issue31_ontologies_wout_aeon
Ad more vocabulary
terms any time…

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Using Page ID a unique ID
 Define a property
 Assign datatype „Text“
 Set property in template
https://fina.oeaw.ac.at/wiki/?curid=10415
 For „Magic Word“ {{PAGEID}} see
 https://www.mediawiki.org/wiki/Help:
Magic_words#Technical_metadata
 https://www.mediawiki.org/wiki/Manual:
Page_table#page_id
{{#set:FINA ID={{PAGEID}}}}

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Excursion: PageIDs
 Set another property PageID
 datatype „Page“
 Use „Query forms“ for an ID
lookup
 See Page Forms extension
 https://www.mediawiki.org/wiki/Extension:
Page_Forms/Creating_query_forms

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Suggest Wikidata property

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Wikidata Mix‘n‘Match
 https://meta.wikimedia.org/wiki/Mix%27n%27match/Manual
 With „Templatefile“ format, it should be possible
to provide a Mix‘n‘match file:
 https://www.semantic-mediawiki.org/wiki/Help:Templatefile_format
 To be used by the M‘n‘M importer
 https://mix-n-match.toolforge.org/import.php

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BEACON
 https://www.semantic-
mediawiki.org/wiki/Help:BEACON

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Reconciliation / OpenRefine
 SMW can provide „result formats“ RDF, JSON,
CSV, etc.
 these an be accessed directly in OpenRefine
 “Reconciliation”
means to look for
data matches with
WikiData
 SMW can re-import
data via DataTransfer
extension

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The Future (of Knowledge Sharing)
 reuse of „Service links“?
 SMW could use the „Reconciliation API“ of
Wikidata
 https://github.com/OpenRefine/OpenRefine/wiki/Reconciliation-Service-API
 Flexibility of SMW property declaration could be
used to map to Wikidata properties
 assign SMW Property:Country to P17
[[Imported from::ow:equivalentClass::P17]]
 this changes RDF output, does not (yet) trigger feature inside SMW
 pushing data to Wikidata (or other repos): should be doable inside
SMW: on a per-entry-base or batch

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Contact
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Bernhard Krabina
 krabina@kdz.or.at
 www.kdz.or.at
 @krabina