Linguistic Linked Open Data, Challenges, Approaches, Future Work
- 1. Linguistic Linked Open Data LLOD Challenges, Approaches, Future Work Sebastian Hellmann TKE 2016 1
- 2. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 AKSW / KILT in Leipzig Leipzig has become one of the largest Semantic Web centers AKSW has 4 subgroups and 45 PhD students http://aksw.org/Team.html Current position: - Head of AKSW / KILT research group (8 PhD students) - Knowledge Integration and Language Technology (KILT) http://aksw.org/Groups/KILT.html - Project manager for 2 H2020 and 1 German research project (BMWi) - http://freme-project.eu/ , http://aligned-project.eu/ , http://smartdataweb.de/ - Executive Director of the DBpedia Association http://dbpedia.org 2
- 3. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 Outline ● The vision behind Linked Data - a technological introduction ● Linguistic Linked Open Data ● Knowledge Modelling vs. Data Encoding ● LIDER ● Challenges and Approaches 3
- 5. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 Web of Data WWW vs. GGG - https://en.wikipedia.org/wiki/Giant_Global_Graph Data on the Web vs. the Web of Data vs. the Semantic Web RDF - Entity Attribute Value - http://dbpedia.org/resource/Copenhagen Three ways to publish RDF: 1. Linked Data: resource-level access via HTTP request (next slide) 2. SPARQL: query access via triplestore database 3. Dump: dataset-level access via bulk download 5
- 6. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 Linked Data Four rules of https://www.w3.org/DesignIssues/LinkedData 1. Use URIs as names for things 2. Use HTTP URIs so that people can look up those names. 3. When someone looks up a URI, provide useful information, using the standards (RDF*, SPARQL) 4. Include links to other URIs. so that they can discover more things. https://en.wikipedia.org/wiki/Copenhagen vs. http://dbpedia.org/resource/Copenhagen Source: https://www.w3.org/DesignIssues/LinkedData.html 6
- 7. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 Open Data != Open Data Open Access vs Open License Open Access means accessible like a web page (often unclear license) http://opendefinition.org by OKFN: “Knowledge is open if anyone is free to access, use, modify, and share it — subject, at most, to measures that preserve provenance and openness.” 7
- 8. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 8 http://lod-cloud.net/
- 9. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 How is the Linked Data Cloud built? 9 - Open Access as the basis - 50 links between things required to receive a dataset link - http://lov.okfn.org - http://datahub.io - Assessing Quantity and Quality of Links Between Linked Data Datasets by Cir Sebastian Hellmann, Kay Müller, and Martin Brümmer in LDOW 2016 http://ev org/ldow2016/papers/LDOW2016_paper_09.pdf
- 10. Linguistic Linked Open Data 10
- 11. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 Linguistic Linked Open Data ● Movement originated in the context of the Working Group for Open Data in Linguistics (OWLG) at Open Knowledge Foundation (OKFN) ● Open is supposed to mean Open license ● Join community mailing list at http://linguistics.okfn.org/ ● Current information at http://linguistic-lod.org/ maintained by John McCrae -> Instructions on how to join the LLOD cloud 11
- 12. January 2011 12
- 13. 13 February 2012 Linked Data in Linguistics. Representing Language Data and Metadata (http://www.springer. com/computer/ai/book/978-3-642-28248-5 ) Christian Chiarcos, Sebastian Nordhoff, and Sebastian Hellmann (Eds.). Springer, Heidelberg, (2012)
- 14. August 2012 14
- 15. Sept 2012 MLODE 15 Special Issue on Multilingual Linked Open Data (MLOD) Editors: Sebastian Hellmann, Steven Moran, Martin Brümm and John McCrae, Semantic Web, vol. 6, no. 4, pp. 315-317, 2015
- 16. Jan 2013 16
- 17. Sep 2013 17 LIDER FP7 EU Project Start: Nov 2013 Duration: 2 years http://lider-project.eu/
- 18. May 2014 18 LIDER FP7 EU Project Start: Nov 2013 Duration: 2 years http://lider-project.eu/
- 19. Nov 2014 19 LIDER FP7 EU Project Start: Nov 2013 Duration: 2 years http://lider-project.eu/
- 20. May 2015 20 LIDER FP7 EU Project Start: Nov 2013 Duration: 2 years http://lider-project.eu/
- 21. May 2016 21 LIDER FP7 EU Project Start: Nov 2013 Duration: 2 years http://lider-project.eu/
- 22. 22
- 23. Should we all use Linked Data? 23
- 24. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 Should we all use Linked Data? When should we use linked data? How should we use linked data? When should we not use it? 24
- 25. Knowledge Modeling vs. Data Encoding 25
- 26. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 Entity Relationship Diagrams and UML 26 The Metadata Ecosystem of the DataId Ontology, Markus Freudenberg, submitted to MTSR Conf 2016 http://dataid.dbpedia.org
- 27. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 XML encoding variants 27
- 28. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 XML encoding variants 28
- 29. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 XML encoding variants <same> should be symmetric, reflexive and transitive https://en.wikipedia.org/wiki/Equivalence_relation Apples and oranges 29
- 30. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 Who can you ask what XML tags and structure mean and what they are used for? 30
- 31. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 Who can you ask what XML tags and structure mean and what they are used for? 31
- 32. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 Internationalization Tag Set (ITS) 2.0 http://www.w3.org/TR/its20/ ● W3C Recommendation since 29 October 2013 ● defines how to embed Machine Translation and Localisation annotations, so called Data Categories, in (X)HTML and XML ● In addition to the human-readable document two ontologies are referenced that capture the semantics of the standard. ● ITS Ontology as companion ● NLP Interchange Format (NIF) is the recommended format for RDF conversion of ITS2.0 http://persistence.uni-leipzig.org/nlp2rdf/ontologies/nif- core 32
- 33. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 Internationalization Tag Set (ITS) 2.0 33 One of the most efficient and robust ways to annotate HTML in a standardized manner
- 34. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 NLP Interchange Format 2.0 (old example) 34
- 35. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 NLP Interchange Format 2.0 (old example) 35
- 36. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 NIF 2.1 release pending Join W3C Community Group: https://www.w3.org/community/ld4lt/ NIF useful for: ● Adding semantics to NLP tool output and corpora ● Providing and publishing identifiers for text and annotations NIF is compact and scalable (cf. http://wiki-link.nlp2rdf.org/ ): ● Google Wikilinks Corpus with 10.6 million webpages and 31.5 million Wikipedia links (about 3 per page) with a zipped size of 180 GB. ● 533 million triples (other formats 7-27% more) ● 79 GB (12 GB gzipped dumps) in Turtle format (original size 180 GB containing HTML markup) 36
- 37. LIDER Towards a linguistic linked data ecosystem 37 Website: http://lider-project.eu Guidelines: http://lider-project.eu/?q=guidelines
- 38. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 NIF 38
- 39. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 LIDER - Deliverable 2.1.2 39 http://www.lider-project.eu/sites/default/files/D2.1.2-Phase-II.pdf
- 40. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 LIDER Reference Architecture Deliverable 3.1.2. General: lemon - developed by 40 http://www.lider-project. eu/sites/default/files/D3.1.2-v2.0.pdf
- 41. Challenges and Work in Progress 41
- 42. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 Identifier management - Ideal identifiers are stable, i.e. the meaning behind the URI does not change - Unrealistic for most use cases - Easier for individuals, i.e. persons, organisations - Non-trivial for terminology Proposals: 1. Apply software development practices, i.e. versioning, update scripts http: //vocol.org , http://github.org , http://aligned-project.eu 2. ?? 42
- 43. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 Knowledge Fusion - Linking is mostly done manual - Linking 200 datasets pairwise requires maintenance of 40000 mappings - Adding one after the other depends on the merge order - Ideally we would be able to structure all datasets into clusters before linking Proposals: 1. Under discussion with: Erhard Rahm - The Case for Holistic Data Integration ADBIS 2016 Keynote: http://adbis2016.vsb.cz/keynote/ (to appear) 2. Apply software development processes: https://github.com/dbpedia/links 43
- 44. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 The Metadata Challenge Where to publish metadata for your data? - Barrier between data and dataset description - Stale metadata - Single point of truth missing - Metadata too heterogeneous - Download link missing - No (sufficiently) complete view over the web of data possible, discovery failure Proposals: 1. build an index: http://linghub.lider-project.eu/ (Clarin, LRE Map, Metashare, Datahub) 2. create a better schema: http://dataid.dbpedia.org and provide benefits for complying 44
- 45. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 MMoOn - LIDER - Lemon - ODRL - Olia - NIF - Morphology quite complex - Specific to language and to the linguist - http://mmoon.org 45
- 46. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 The Metadata Challenge 2 ● RDF structure is too simple to keep additional metadata ○ Scope ○ Validity ○ Confidence ○ Technical metadata, i.e. collection time Contextualisation is probably already better researched in lexicography than in Semantic Web. 46
- 47. Future work and take home messages 47
- 48. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 ● Data Quality can be defined and measure with the tools. ● http://svn.aksw.org/papers/2014/WWW_Databugger/public.pdf Test-driven Evaluation of Linked Data Quality by Dimitris Kontokostas, Patrick Westphal, Sören Auer, Sebastian Hellmann, Jens Lehmann, Roland Cornelissen, and Amrapali J. Zaveri in Proceedings of the 23rd International Conference on World Wide Web ● Current standard: ○ https://www.w3.org/TR/shacl/ Data quality and verification 48
- 49. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 Open licenses in research 49 Are you willing to publish your data under an open license? Can you make a product out of your data? No Yes Start Congratulations, your paper has been accepted Yes Good luck, we wish you all the best and a high profit No
- 50. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 Entity Linking Verification - new translator job profile ● http://www.freme-project.eu/ ● Business Case: Integrating semantic enrichment into multilingual content in translation and localisation ● In the future, translators and lexicographers might be asked to judge entity linking and verify data 50
- 51. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 Should I invest in publishing linked data? Long-term data strategy, if you: ● Have many expected inbound links ● Persistent ids ● Long term hosting and curation Is no problem for you -> yes (data value increases) One time thing: ● Interest of externals only in the yellow zone -> Publish under open license (let someone else do it) 51
- 52. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 DBpedia Association DBpedia+ ● Maintain identifier space ● Add open and member data to DBpedia+ ● Add data following the LIDER guidelines ● Ability to add your backlinks DBpedia Community meeting on the 15th of September in Leipzig 52
- 53. Sebastian Hellmann - AKSW/KILT Copenhagen TKE 2016 Events in 2016 ● KEKI 2016 Workshop - Uses of Linguistic Linked Open Data http://keki2016. linguistic-lod.org/ Deadline is 1st of July, but might be extended ● http://2016.semantics.cc 53