Date post: | 16-Mar-2018 |
Category: |
Data & Analytics |
Upload: | enrico-daga |
View: | 138 times |
Download: | 0 times |
Linked Data at the OU: the Story so far
1
Enrico Daga Knowledge Media Ins0tute, The Open University (UK)
‘Making Data Work for You' -‐ 5th October The Open University
Feedback welcome: @enridaga #kmiou
Outline
• Linked Data in a nutshell• Linked Data at the OU: data.open.ac.uk • data.open.ac.uk developer toolkit• Three typical use cases• Issues and perspectives
2
Linked Data in a nutshell
Linked Open Data is a way of publishing structured data that allows metadata to be connected and enriched, so that links can be made between related resources.
• LD uses the World Wide Web as publishing platform• Based on W3C standards - open to everyone• Enables your data to refer to other data• … and other data to refer to yours!
3
hPps://en.wikipedia.org/wiki/Linked_data
Linked Data Technology Stack
• Uniform Resource Identifiers (URIs)– To identify things
• HyperText Transfer Protocol (HTTP)– To access data about them
• Resource Description Framework (RDF)– a meta-model for data representation. – it does not specify a particular schema– offers a structure for representing it
• SPARQL Protocol and Query Language (SPARQL)– To query LD databases directly on the Web
4
RDF Triple
5
RDF Data
6Feedback welcome: @enridaga #kmiou
RDF Data
• Its both human readable and machine readable.• You can represent any type of data structure in RDF!– trees, sequences, sets, tables, graphs, …
• Vocabularies specify schema terms:– FOAF, BIBO, DCAT, OWL, SKOS, QB, …– Explore them: http://lov.okfn.org/
• Especially, you can refer to data outside your dataset
7
Linked Data Applications
• Open Data• Cultural Heritage• Digital Libraries• Scholar Publishing• Enterprise/Corporate, as part of data warehouse
8
Linked Open Data Cloud (2007)
9hPp://lod-‐cloud.net/
Linked Open Data Cloud (2008)
10hPp://lod-‐cloud.net/
Linked Data: The story so far (2009)
11
Linked Open Data Cloud (2010)
12hPp://lod-‐cloud.net/
data.open.ac.uk• data.open.ac.uk is the home of OU linked open data. • From 2010, OU first university in the UK to publish linked
open data.• We collect, interlink and expose data from institutional
repositories of the University, and we make it available as Linked Data in one single database.
13Feedback welcome: @enridaga #kmiou
http://data.open.ac.uk
14
Mathieu d’Aquin (formerly KMi)
Stuart Brown (formerly COMMS)
Datasets
Open Educational Resources• Metadata about educational resources produced or co-produced by The Open
University• OU/BBC Coproductions | OU podcasts | OpenLearn | Videofinder
Scientific Production• Metadata about scientific production of The Open University• Open Research Online
Social Media• Content hosted by social media web sites. Metadata are extracted from public
APIs and aggregated into RDF.• Audioboo | YouTube
15
Datasets
Organisational• Data collected form internal repositories and first made public as linked
data.• The OU's Key Information Set from Unistats | OU People Profiles | KMi
People Profiles | Open University data XCRI-CAP 1.2 | Qualifications | Courses | OU Planet Stories
Data from Research Projects• Linked Data from research projects.• Arts and Humanities Research Council project metadata | The
Listening Experience Database | The UK Reading Experience Database | The Reading Experience Database: DBpedia alignments
16
In numbers
2017• ~7M triples• 37 graphs• ~1M entities• 173 entity types• >1K predicates• >1M links
17Feedback welcome: @enridaga #kmiou
2014 • ~4M triples• 30 graphs• ~700k entities• 125 entity types• ~700 predicates• ~600k links
Daga, E., d’Aquin, M., Adamou, A., & Brown, S. (2016). The Open University Linked Data–data. open. ac. uk. Seman0c Web, 7(2), 183-‐191.
data.open.ac.uk for developers
Toolkit:• Entity Lookup • Data browser• SPARQL Endpoint• Web APIs
18Feedback welcome: @enridaga #kmiou
Data Browser
20
SPARQL Endpoint
21
Results as CSV, JSON, XML, …
SPARQL example: courses and podcasts
22
SELECT DISTINCT ?topic from <http://data.open.ac.uk/context/podcast> where { ?podcast <http://data.open.ac.uk/podcast/ontology/relatesToCourse> <http://data.open.ac.uk/course/ms221> . ?podcast <http://purl.org/dc/terms/isPartOf>/<http://purl.org/dc/terms/subject> ?topic }
List of topics of podcasts related to course MS221
SPARQL example: courses and podcasts
23
Videos from the Open University on YouTube.
YouTube videos are linked to courses and qualifications, which in turn are linked to other entities (OpenLearn units, Podcasts, Audios, and other Courses or Qualifications)
Find OU content related to a YouTube video from the YouTube video id (eg: SYry6PYsL8o)
prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> prefix podcast: <http://data.open.ac.uk/podcast/ontology/> prefix yt: <http://data.open.ac.uk/youtube/ontology/> prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> prefix rkb: <http://courseware.rkbexplorer.com/ontologies/courseware#> prefix saou: <http://data.open.ac.uk/saou/ontology#> prefix dbp: <http://dbpedia.org/property/> prefix media: <http://purl.org/media#> prefix olearn: <http://data.open.ac.uk/openlearn/ontology/> prefix mlo: <http://purl.org/net/mlo/> prefix bazaar: <http://digitalbazaar.com/media/> prefix schema: <http://schema.org/>
SELECT distinct (?related as ?identifier) ?type ?label (str(?location) as ?link)
FROM <http://data.open.ac.uk/context/youtube> FROM <http://data.open.ac.uk/context/podcast> FROM <http://data.open.ac.uk/context/openlearn> FROM <http://data.open.ac.uk/context/course> FROM <http://data.open.ac.uk/context/qualification> WHERE { ?x schema:productID "SYry6PYsL8o" . # change the youtube id to any OU youtube video ?x yt:relatesToCourse ?course . { # related video podcasts ?related podcast:relatesToCourse ?course . ?related a podcast:VideoPodcast . ?related rdfs:label ?label . optional { ?related bazaar:download ?location } BIND( "VideoPodcast" as ?type ) . } union { # related audio podcasts ?related podcast:relatesToCourse ?course . ?related a podcast:AudioPodcast . ?related rdfs:label ?label . optional { ?related bazaar:download ?location } BIND( "AudioPodcast" as ?type ) . } union { # related openlearn units ?related a olearn:OpenLearnUnit . ?related olearn:relatesToCourse ?course . BIND( "OpenLearnUnit" as ?type ) . ?related <http://dbpedia.org/property/url> ?location . ?related rdfs:label ?label . } union { # related qualifications (compulsory course) ?related a mlo:qualification . ?related saou:hasPathway/saou:hasStage/saou:includesCompulsoryCourse ?course . BIND( "Qualification" as ?type ) . ?related rdfs:label ?label . ?related mlo:url ?location } } limit 200
BASIL - Sharing and Reusing SPARQL Queries as Web APIs
24
BASIL API
consumesdata or views
WebAPI
Web developers
REST
tailors WEB API(SPARQL query)
WebAPI
defines view(template)
WebAPI
WebAPI
WebAPI
clones WEB API
Linked Data Cloud
SPARQL
ht tp : / /bas i l .kmi .open.ac.uk/
Listening Experience DatabaseAn open and freely searchable database that brings together a mass of data about people’s experiences of listening to music of all kinds, in any historical period and any culture.
Uses data.open.ac.uk as publishing platform.
25
hPp://led.kmi.open.ac.uk/
Feedback welcome: @enridaga #kmiou
Typical use case #1
Online Student Help CentreUses data.open.ac.uk to get the list of courses, modules, and qualifications.
Gets key data facts for student self-service (reduction of avoidable contact).
Enables students to find the right dept/person to contact in the OU.
26
hPps://help.open.ac.uk
Feedback welcome: @enridaga #kmiou
Thanks: Guy Carberry (Academic Services), Sam Leicester (developer)
Typical use case #2
OpenLearn
Uses data.open.ac.uk to get content recommendations (eg: courses).
data.open.ac.uk drives the click through which turns OpenLearn visitors into OU students!
Publish once, display everywhere (from YouTube, Audioboo, iTunesU, Podcast)
27
hPp://www.open.edu/openlearn/
Thanks: Simon Budgen (OMIL), Michael Brodbin (Psychle)
Typical use case #3
Issues
• Data not (always) complete - sometimes with good reason (private data), sometimes not (organisational).
• Understand data supply: knowing who knows what in the OU is not easy.
• Express data demand: how to ask for data?• Operationalise data integration requires (good and
committed) developers.• Expertise: developing the needed skills might be easier than
expected. KMi can help on that.• Building the tools is neither half the job: maintenance and
curation is crucial.
28
Summary
• data.open.ac.uk started as a research prototype in 2010, today is the hub of OU Linked Data.
• Key services of the OU rely on data.open.ac.uk to support various types of users.
• LD is great for centralised data publishing.• Does not substitute data management platforms, but
integrates with existing workflows.
29
Take-away messages
• A large organisation such the OU cannot afford to rely on separated, autistic systems.• We need systems that TALK to each other.
• LD helps to look at the data life-cycle as a supply-chain, to focus on supply and demand.
• We need a registry: who knows / needs what.• We don’t need shiny user interfaces (we do, but …)• Developers first-class citizens: enable them first.
30Feedback welcome: @enridaga #kmiou
31
"Linking Open Data cloud diagram 2017, by Andrejs Abele, John P. McCrae, Paul Buitelaar, Anja Jentzsch and Richard Cyganiak. hPp://lod-‐cloud.net/"
Thank you
Twitter: @[email protected]