Web Science Synergies: Exploring Web Knowledge through the Semantic Web
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The document discusses exploring web data and knowledge through the semantic web. It describes how the semantic web adds meaning to data through shared vocabularies and schemas. It also discusses challenges with the large number and diversity of linked open datasets, including issues with accessibility, heterogeneity of schemas, and data quality. It proposes approaches to address these challenges, such as dataset profiling, metadata catalogs, and infrastructure for federated querying.
![Open data is more diverse than we think
SPARQL Web-Querying Infrastructure: Ready for Action?,
Carlos Buil-Aranda, Aidan Hogan, Jürgen Umbrich Pierre-Yves
Vandenbussch, International Semantic Web Conference 2013,
(ISWC2013).
Accessibility of datasets?
Less than 50% of all SPARQL endpoints actually responsive
at given point of time
“THE” SPARQL protocol? No, but many variants & subsets
…
SPARQL endpoint availability over time [Buil-Aranda et al 2013]
Shared vocabularies & schemas, but:
…still very heterogeneous [d’Aquin, WebSci13]
…data partially messy an not conformant
(RDFS, schemas) [HoganJWS2012]
Co-occurence graph of data
types in 146 datasets: 144
Vocabularies, 588 highly
overlapping types, 719
Properties
…even widely used reference datasets such as
DBpedia noisy [Paulheim2013]
Assessing the Educational Linked Data Landscape, D’Aquin, M.,
Adamou, A., Dietze, S., ACM Web Science 2013 (WebSci2013), Paris,
France, May 2013.
Type Inference on Noisy RDF Data, Paulheim H., Bizer, C. Semantic
Web – ISWC 2013, Lecture Notes in Computer Science Volume 8218,
2013, pp 510-525
Stefan Dietze
An empirical survey of Linked Data conformance. Hogan, A., Umbrich,
J., Harth, A., Cyganiak, R., Polleres, A., Decker., S., In the Journal of Web
Semantics 14: pp. 14–44, 2012](https://image.slidesharecdn.com/dietze-semanticweb-websciencesynergies-2013-131127104516-phpapp02/85/Web-Science-Synergies-Exploring-Web-Knowledge-through-the-Semantic-Web-6-320.jpg)
Web Science Synergies: Exploring Web Knowledge through the Semantic Web
- 1. Exploring Web Data & Knowledge through the Semantic Web Dr. Stefan Dietze L3S Research Center Stefan Dietze 27/11/13 1
- 2. Pluto & the seven Dwarfs? pluto the dwarf planet ? „…solar system… #pluto“ Stefan Dietze 27/11/13
- 3. “A little semantics goes a long way” (J. 1) Hendler yago:AstronomicalObjects Semantic Web Adding meaning through shared vocabularies and schemas (eg DBpedia) W3C standards RDF & SPARQL for data & knowledge representation and querying Persistent URIs to reference & interlink data on the Web dbp:CelestialBody typeOf typeOf dbp:Pluto dwarfPlanetOf redirectOf dbp:SolarSystem namedAfter dbp:Pluto(mythology) dbp:DwarfPlanetPluto „…solar system… #pluto“ 1 Hendler, J., The Dark Side of the Semantic Web, IEEE Intelligent Systems, Jan/Feb 2007
- 4. Semantic Web / Linked Data De-facto standard for sharing data on the Web Vision: well connected graph of open Web data 350+ datasets and 32 billion triples in LOD Cloud alone Other „incarnations“: Google „HTTP-accessibility“ (SPARQL, URI-dereferencing) Knowledge Graph Facebook Open Graph „Structure“ & „Semantics“ (=> shared/linked vocabularies) http://schema.org BBC Program mes „Interlinked“ „Persistent“ FOAF DBpedia Ontology Geo Ontology Gene Ontology Stefan Dietze Dublin Core BIBO
- 5. That’s awesome, but... Hm, really? …why are there so few datasets actually used? Date reuse and in-links focused on trusted „reference graphs“ such as DBpedia (i.e. Wikipedia) Long tail of LD datasets which are neither reused nor linked to (LOD Cloud alone consists of 300+ datasets) „HTTP-accessibility“ (SPARQL, URI-dereferencing) Explanations? „Structure“ & „Semantics“ (=> shared/linked vocabularies) „Interlinked“ „Persistent“ Stefan Dietze 27/11/13
- 6. Open data is more diverse than we think SPARQL Web-Querying Infrastructure: Ready for Action?, Carlos Buil-Aranda, Aidan Hogan, Jürgen Umbrich Pierre-Yves Vandenbussch, International Semantic Web Conference 2013, (ISWC2013). Accessibility of datasets? Less than 50% of all SPARQL endpoints actually responsive at given point of time “THE” SPARQL protocol? No, but many variants & subsets … SPARQL endpoint availability over time [Buil-Aranda et al 2013] Shared vocabularies & schemas, but: …still very heterogeneous [d’Aquin, WebSci13] …data partially messy an not conformant (RDFS, schemas) [HoganJWS2012] Co-occurence graph of data types in 146 datasets: 144 Vocabularies, 588 highly overlapping types, 719 Properties …even widely used reference datasets such as DBpedia noisy [Paulheim2013] Assessing the Educational Linked Data Landscape, D’Aquin, M., Adamou, A., Dietze, S., ACM Web Science 2013 (WebSci2013), Paris, France, May 2013. Type Inference on Noisy RDF Data, Paulheim H., Bizer, C. Semantic Web – ISWC 2013, Lecture Notes in Computer Science Volume 8218, 2013, pp 510-525 Stefan Dietze An empirical survey of Linked Data conformance. Hogan, A., Umbrich, J., Harth, A., Cyganiak, R., Polleres, A., Decker., S., In the Journal of Web Semantics 14: pp. 14–44, 2012
- 7. Too many/diverse datasets, too little information Which datasets are useful & trustworthy for case XY (eg „learning about the solar system“) ? Which topics (eg „Astronomy“) are covered by dataset X? Which datasets describe/offer videos (slides, publications, statistics etc)? ? ? ? Stefan Dietze 27/11/13
- 8. Data curation and dataset profiling Which datasets are useful & trustworthy for case XY (eg „learning about the solar system“) ? Which topics (eg „Astronomy“) are covered by dataset X? Which datasets describe/offer videos (slides, publications, statistics etc)? Catalog of data (LinkedUp Catalog): classification of datasets according to resource types, disciplines/topics, data quality, accessability, etc Infrastructure for distributed/federated querying describes Stefan Dietze LinkedUp Dataset Catalog 27/11/13
- 9. Dataset profiling: what’s all the data about po:Programme AAISO BBC Programme bibo:Fi bibo:Film bibo:Fil BIBO FOAF <po:Programme …> <po:Series>Wonders of the Solar System</.> <po:Actor>Brian Cox</…> </po:Programme…> Schema mappings yov:Video contains Yovisto Video <yo:Video …> <dc:title>Pluto & the Dwarf Planets</dc:title> … </yo:Video…> Entity disambiguation db:Astro. Objects db:Astro. Objects db:Astronomy Topic profile extraction Dataset Metadata Stefan Dietze LinkedUp Dataset Catalog 27/11/13
- 10. LinkedUp Data Catalog inExplore & query for datasets/types & topics a nutshell http://data.linkededucation.org/linkedup/categories-explorer http://data.linkededucation.org/linkedup/catalog/ Federated queries using type mappings Stefan Dietze 27/11/13
- 11. LinkedUp Challenge: using open data for learning http://linkedup-challenge.org Open Data Competition to promote tools and applications that analyse / integrate (Linked) Web data Organised by LinkedUp project over 2 years (“Veni”, “Vidi”, “Vici”) with 40.000 EUR awards Veni Competition - 22 submissions, 8 shortlisted for presentation at Open Knowledge Conference (17 September, Geneva Switzerland) Stefan Dietze 27/11/13
- 12. st 1 Place: PoliMedia Exploring political debates & events http://www.polimedia.nl/ Cross-media exploration & analysis of political events (parliament debates and media coverage) Automatically generated links between transcripts debates, newspaper articles, and radio bulletins. (Linked) Data available at http://data.polimedia.nl Data sources: 1) newspapers of the historical newspaper archive, 2) radio bulletins of the Dutch National Press Agency (ANP) 9000+ debates (1945 – 1995) Over 3000 media links Martijn Kleppe, Max Kemman, Henri Beunders (Erasmus Universiteit Rotterdam), Laura Hollink Damir Juric (Vrije Universiteit Amsterdam), Johan Oomen Jaap Blom (Nederlands Instituut voor Beeld en Geluid) Stefan Dietze 27/11/13
- 13. Outlook: more “focused” data reuse challenges http://linkedup-challenge.org/ Open Track Focused Track Scalable tools and applications using (Linked) open data for educational purposes LinkedUp data catalog Promotion of selected Veni submissions Simplifying complex information to make it accessible (example: publications from Elsevier) Recommender system for educational resources (courses, MOOCs) relevant to user interests Approx. 20.000 EUR awards budget Final events at 11th Extended Semantic Web Conference (ESWC2014) Submission: 14 February 2014 Stefan Dietze 27/11/13 13
- 14. Thank you! REFERENCES WWW Assessing the Educational Linked Data Landscape, D’Aquin, M., Adamou, A., Dietze, S., ACM Web Science 2013 (WebSci2013), Paris, France, May 2013. See also (data) Generating structured Profiles of Linked Data Graphs, Fetahu, B; Dietze, S., d’Aquin, M., Nunes, B.P., ISWC2013 – 12th International Semantic Web Conference; http://datahub.io/group/linked-education http://data.linkededucation.org http://data.linkededucation.org/linkedup/catalog/ http://lak.linkededucation.org Combining a co-occurrence-based and a semantic measure for entity linking, B. P. Nunes, S. Dietze, M.A. Casanova, R. Kawase, B. Fetahu, and W. Nejdl., ESWC 2013 - 10th Extended Semantic Web Conference, (May 2013). See also (general) Type Inference on Noisy RDF Data, Paulheim H., Bizer, C. Semantic Web – ISWC 2013, Lecture Notes in Computer Science Volume 8218, 2013, pp 510-525 An empirical survey of Linked Data conformance. Hogan, A., Umbrich, J., Harth, A., Cyganiak, R., Polleres, A., Decker., S., In the Journal of Web Semantics 14: pp. 14–44, 2012 http://linkedup-project.eu http://linkedup-challenge.org http://linkededucation.org http://linkeduniversities.org SPARQL Web-Querying Infrastructure: Ready for Action?, Carlos BuilAranda, Aidan Hogan, Jürgen Umbrich Pierre-Yves Vandenbussch, International Semantic Web Conference 2013, (ISWC2013). Stefan Dietze 27/11/13 14