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A Bottom-Up Approach for Licences
Classification and Selection
1
Enrico Daga (KMi-OU)
Mathieu d’Aquin (KMi-OU)
Aldo Gangemi...
Background
• Licences are important in the web of (linked) data
• We can describe licences/policies (RDF+ODRL)
• Exploitin...
Question
How can we reduce the effort for licence
identification and selection?
3
Hypothesis
An ontology defining relevant classes of
licences, formed on the basis of the key
features of the instances, sho...
Methodology
A bottom-up approach to ontology construction
• RDF License Database
• Ontology production with Contento
• Bas...
Formal Concept Analysis (FCA)
• A data analysis method
• Studies how objects can be hierarchically grouped together
accord...
7
Contento
http://bit.ly/contento-tool
Support the user in the generation and curation of concept
lattices from formal con...
8
Contento
http://bit.ly/contento-tool
Support the user in the generation and curation of concept
lattices from formal con...
RDF License Database
http://datahub.io/dataset/rdflicense *
~140 licences expressed in RDF/ODRL
9
<hCp://purl.org/NET/rdflic...
Formal Context
Objects: Apache 2.0, CC-A-SA 3.0, …
Attributes: duty attribution, permission Copy, prohibition derive, …
10...
Concept Lattice
• Applying FCA, a concept lattice is produced
• The top concept representing All the licences, while the b...
Modeling: Naming & Pruning
• Inspect each concept
• If it is meaningful annotate it
– eg: “should others be allowed
to dis...
• Approach: a concept is
meaningful if it’s intent
introduces new features
(policies)
• If not:
– it is a union of the int...
Modeling: Naming & Pruning
• With this process the lattice has been reduced significantly.
• Almost 20% of the initial latt...
Export as OWL Ontology
15
rdfs:subClassOf
rdf:type
ex:has-­‐aBribute 	
  .	
  .	
  .
give semantics!
Fo Co MR LicEx
contento_ns:7582 rdf:type contento:Concept ;
rdfs:label "Copyleft" ;
rdfs:comment "Should the licence require to share any...
Evaluation The Licence Picker Webapp
http://bit.ly/licence-picker-webapp
17
The user is engaged in
answering questions reg...
Conclusions and Future Work
• A bottom-up approach on ontology building in this scenario opens
new interesting challenges
...
Thank you
Enrico Daga
enrico.daga@open.ac.uk
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A bottom up approach for licences classification and selection

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Presented at the LeDa-SwAn Workshop at ESWC2015

http://cs.unibo.it/ledaswan2015

#ledaswan2015

Licences are a crucial aspect of the information publishing process in the web of (linked) data. Recent work on modeling of policies with semantic web languages (RDF, ODRL) gives the opportunity to formally describe licences and reason upon them. However, choosing the right licence is still challenging. Particularly, understanding the number of features - permissions, prohibitions and obligations - constitute a steep learning process for the data provider, who has to check them individ- ually and compare the licences in order to pick the one that better fits her needs. The objective of the work presented in this paper is to reduce the e↵ort required for licence selection. We argue that an ontology of licences, organized by their relevant features, can help providing support to the user. Developing an ontology with a bottom-up approach based on Formal Concept Analysis, we show how the process of licence selection can be simplified significantly and reduced to answering an average of three/five key questions.

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A bottom up approach for licences classification and selection

  1. 1. A Bottom-Up Approach for Licences Classification and Selection 1 Enrico Daga (KMi-OU) Mathieu d’Aquin (KMi-OU) Aldo Gangemi (CNR & Universite’ Paris13) Enrico Motta (KMi-OU) June  1st,  2015     Interna0onal  Workshop  on  Legal  Domain  And  Seman0c  Web  Applica0ons     ESWC  2015  Workshop   hCp://cs.unibo.it/ledaswan2015
  2. 2. Background • Licences are important in the web of (linked) data • We can describe licences/policies (RDF+ODRL) • Exploiting these descriptions for license selection is hard due to the high number of different features 2
  3. 3. Question How can we reduce the effort for licence identification and selection? 3
  4. 4. Hypothesis An ontology defining relevant classes of licences, formed on the basis of the key features of the instances, should facilitate the selection and identification of a suitable licence. 4
  5. 5. Methodology A bottom-up approach to ontology construction • RDF License Database • Ontology production with Contento • Based on Formal Concept Analysis • User can annotate and prune concepts • Produces an OWL Ontology • License Picker Ontology (LiPiO) • Evaluation: License Picker Webapp 5
  6. 6. Formal Concept Analysis (FCA) • A data analysis method • Studies how objects can be hierarchically grouped together according to their common attributes • Input is a Formal Context – a binary matrix of objects/attributes • Basic unit is a Concept: – (O,A) => (Extension,Intension) – Operator ’ … (O,A) is a concept when O’=A and A’=O • Classifies concepts hierarchically in a concept lattice – Top: all objects, no attr, bottom: all attributes, no obj 6
  7. 7. 7 Contento http://bit.ly/contento-tool Support the user in the generation and curation of concept lattices from formal contexts and use them as semantic web ontologies. Formal   Context Concept   LaNce Modeling   (Naming  &   Pruning) Export  as   OWL   Ontology
  8. 8. 8 Contento http://bit.ly/contento-tool Support the user in the generation and curation of concept lattices from formal contexts and use them as semantic web ontologies. Formal   Context Concept   LaNce Modeling   (Naming  &   Pruning) RDF  Licence   Database Licence   Picker   Ontology Export  as   OWL   Ontology Fo Co MR LicEx
  9. 9. RDF License Database http://datahub.io/dataset/rdflicense * ~140 licences expressed in RDF/ODRL 9 <hCp://purl.org/NET/rdflicense/cc-­‐by-­‐nc4.0>              a              odrl:Policy  ;              rdfs:label  "Crea0ve  Commons  CC-­‐BY-­‐NC"  ;              rdfs:seeAlso  <hCp://crea0vecommons.org/licenses/by-­‐nc/4.0/legalcode>  ;              cc:legalcode  <hCp://crea0vecommons.org/licenses/by-­‐nc/4.0/>  ;              dct:alterna0ve  "CC  BY-­‐NC"  ;              dct:hasVersion  "4.0"  ;              dct:language  <hCp://www.lexvo.org/page/iso639-­‐3/eng>  ;              dct:publisher  "Crea0ve  Commons"  ;              dct:0tle  "Crea0ve  Commons  -­‐  ACribu0on-­‐NonCommercial  4.0  Interna0onal  -­‐  CC  BY-­‐NC  4.0"@en  ;              odrl:permission                  [  odrl:ac0on  cc:Distribu8on  ,  ldr:extrac8on  ,  ldr:reu8liza8on  ,  cc:Deriva8veWorks  ,  cc:Reproduc8on  ;              odrl:duty    [  odrl:ac0on  cc:ABribu8on  ,  cc:No8ce]  ]  ;              odrl:prohibi8on                              [  odrl:ac0on  cc:CommercialUse  ]  ;              foaf:logo  <hCp://i.crea0vecommons.org/l/by-­‐nc/2.0/88x31.png>  . Fo Co MR LicEx (*) Victor Rodrıguez-Doncel, Serena Villata, and Asuncion Gomez-Ṕerez. A dataset of RDF licenses. In Rinke Hoekstra, editor, Legal Knowledge and Information Systems. JURIX 2014: The Twenty-Seventh Annual Conference. IOS Press, 2014. 

  10. 10. Formal Context Objects: Apache 2.0, CC-A-SA 3.0, … Attributes: duty attribution, permission Copy, prohibition derive, … 10 RDF     Licence   Database Licence,Policy,Bool   Apache,Duty  No0ce,True   …   (as  CSV) Fo Co MR LicEx
  11. 11. Concept Lattice • Applying FCA, a concept lattice is produced • The top concept representing All the licences, while the bottom concept, None, includes all the attributes, and no licence. • However, this lattice need to be interpreted… 11 Fo Co MR LicEx
  12. 12. Modeling: Naming & Pruning • Inspect each concept • If it is meaningful annotate it – eg: “should others be allowed to distribute the work?” • … otherwise delete it – and the hierarchy is adjusted accordingly – objects are present in direct upper concepts, attributes in direct lower 12 Fo Co MR LicEx
  13. 13. • Approach: a concept is meaningful if it’s intent introduces new features (policies) • If not: – it is a union of the intents of the respective upper concepts, – the respective licences will be present in (at least one of) the upper concepts, – no new question need to be asked to identify them. 13 Modeling: Naming & Pruning Fo Co MR LicEx
  14. 14. Modeling: Naming & Pruning • With this process the lattice has been reduced significantly. • Almost 20% of the initial lattice • Labels being synthetic names referring to policies/attributes that have been introduced in that point of the hierarchy • Each concept has a Question 14 Fo Co MR LicEx
  15. 15. Export as OWL Ontology 15 rdfs:subClassOf rdf:type ex:has-­‐aBribute  .  .  . give semantics! Fo Co MR LicEx
  16. 16. contento_ns:7582 rdf:type contento:Concept ; rdfs:label "Copyleft" ; rdfs:comment "Should the licence require to share any derived or combined content under the same terms?" ; rdfs:subClassOf contento_ns:7856 , contento_ns:7678 , contento_ns:7956 . contento_ns:7586 rdf:type contento:Concept ; rdfs:label "Read" ; rdfs:comment "Should the licence permit to read (access) the data?" ; rdfs:subClassOf contento_ns:7648 . contento_ns:7632 rdf:type contento:Concept ; rdfs:label "ND" ; rdfs:comment "Should the licence prohibit derivative works?" ; The Licence Picker Ontology http://bit.ly/licence-picker-ontology Can be exploited as a decision tree! 16 Focus is on Key Questions Fo Co MR LicEx
  17. 17. Evaluation The Licence Picker Webapp http://bit.ly/licence-picker-webapp 17 The user is engaged in answering questions regarding her requirements By applying the Licence Picker Ontology (LiPiO), this task is reduced to answering an average of 3/5 questions and assessing the best licence from a small set of choices.
  18. 18. Conclusions and Future Work • A bottom-up approach on ontology building in this scenario opens new interesting challenges • The RDF description of licences is an ongoing work • Data has been curated in advance (harmonised) • Data has impact on the whole process! – explore methods to automate some of the curation tasks (especially pruning) – to integrate changes in the formal context incrementally – to support the ontology designer in the adaptation of the ontology • New features: type of asset, jurisdiction … • Contento: a generic tool, need user-based evaluation 18
  19. 19. Thank you Enrico Daga enrico.daga@open.ac.uk

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